There are many isolated endorheic lakes in the transvolcanic belt of Mexico, which are the result of volcanism or extreme flooding. Organisms living in the lakes have had ample time to differentiate, and endemism is well known and documented, especially among the fishes. Other organisms also show endemism, including salamanders, crayfish, and even birds and mammals. The same is true for the garter snake, Thamnophis eques (Reuss). Seven new subspecies are described in this paper, each from a different lake or from the remnants of a former large lake. Based on morphological differences in coloration and pattern, they are Thamnophis eques cuitzeoensis from El Lago de Cuitzeo, Thamnophis eques patzcuaroensis from El Lago de Pátzcuaro, Thamnophis eques insperatus from La Laguna de Zacapu, Thamnophis eques obscurus from El Lago de Chapala, Thamnophis eques diluvialis from Las Lagunas Atotonilco and Cajititlán and several isolated localities, Thamnophis eques scotti from El Lago de Magdalena, and Thamnophis eques carmenensis from La Lagunilla del Carmen. Among six of these, series of specimens were collected and studied in detail. The seventh (insperatus) is known only from a single imperfect individual.
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22 May 2003
Observations on Garter Snakes of the Thamnophis eques Complex in the Lakes of Mexico's Transvolcanic Belt, with Descriptions of New Taxa
ROGER CONANT
Author Affiliations +
ROGER CONANT*
*Research Associate, Division of Vertebrate Zoology (Herpetology), American Museum of Natural History; Adjunct Professor, Department of Biology, University of New Mexico
*Research Associate, Division of Vertebrate Zoology (Herpetology), American Museum of Natural History; Adjunct Professor, Department of Biology, University of New Mexico
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ARTICLE - INTRODUCTION
- Procedures
- Instruments Used for Recording Data
- Illustrations
- Problems
- USE OF THE NAME THAMNOPHIS EQUES
- The Species Model
- Scutellation: Nine crown scutes (paired internasals, prefrontals, supraoculars, and parietals, and a single frontal). Rostral wider than high and barely visible from above. Two nasals, the anterior bearing the nostril entirely within it. Loreal subtrapezoidal, about as wide as high. One preocular; 3 postoculars. One temporal anteriorly; 2 posteriorly. Supralabials 8, sixth and seventh largest, fourth and fifth entering orbit. Infralabials 10, sixth the largest, and first pair meeting on the midventral line; first five on each side in contact with the corresponding chin shield. Two pairs of chin shields, the posterior longer than the anterior.
- Dorsal scales carinate throughout the length of the body and most of the tail; keels weak on the first row of scales on each side of body. Apical pits, if present, are most apt to be found in the nuchal region. Scale rows most frequently 21–19–17. Anal plate single (undivided). Ventrals variable, subcaudals variable, and total and tail lengths variable.
- Whereas the scutellation is relatively similar in the separate populations, coloration and pattern vary distinctly from one lake to another. They are described in detail for each taxon.
- Pattern: A few more or less constant pattern details are as follows: When three pale longitudinal stripes are present, the central one occupies the middorsal row of scales and parts of adjacent rows depending on the subspecies involved. The lateral stripes occupy scale rows 3 and 4 anteriorly and rows 2 and 3 or row 3 only posteriorly. Small paired yellowish parietal spots. Labials whitish or yellowish, the sutures of the labials black. A yellowish crescent two scales wide posterior to the temporals, followed posteriorly by a black semicrescent two scales wide. When markings are present between the light stripes they are usually black or dark brown, paired but variable in size and position. Venter often gray. A black crossline at the base of each ventral, but hidden or not by the overlapping preceding scute. Underside of tail, chin, and throat whitish or yellowish and unmarked. Anal plate similar in coloration or same color as venter in general.
- In the descriptions of holotypes in the text below all scutellation features are the same as those in the hypothetical specimen, except as indicated. Patterns and coloration are described in full.
- MEXICO'S TRANSVOLCANIC BELT
- INTERNATIONAL INTEREST
- TRANSVOLCANIC BELT ENDEMISM
- EL LAGO DE CUITZEO
- Thamnophis eques cuitzeoensis, new subspecies Figures 2, 3
- Holotype: AMNH 93915, a large gravid female from ∼100 m east of the southern end of the south–north causeway across the Lago de Cuitzeo, Michoacán, Mexico, collected August 5, 1964, by Roger Conant. Total length 1020 mm, tail length 229 mm, tail/total length = 0.225.
- Paratopotypes: AMNH 85141–85146, 87530–87542, 88710, 88711, 93901–93914, 93916–93933 (young born to the holotype in captivity on September 13, 1964), 93934, and 96846–96851, all from near the south end of the causeway, and taken, collectively, on August 16, 1960, August 20, 1961, August 5–6, 1964, and August 3–4, 1965. The nearest settlement, Cato del Porvenir, is 5 km south of the causeway.
- Etymology: Derived from Cuitzeo + the adjectival-forming suffix –ensis (belonging to a place).
- Diagnosis: A race of Thamnophis eques characterized by its virtually uniform, intense black pigmentation. Traces of a striped and spotted pattern may appear in the young, especially on or near the head, and the pattern is sometimes faintly discernible in adults that have just shed their skins or in specimens that have been preserved for many years; in essence, however, the dorsum of virtually all individuals is jet black (fig. 3). The venter is also black and dark gray, with the exception of the chin and throat and the underside of the tail, which are white or cream-colored without dark markings, and are strikingly in contrast with the remainder of the under surface. The anal plate may be light or dark or partly both. Most populations of the T. eques complex from other localities bear pale longitudinal stripes or paired dark lateral spots or both. Neonates and the other young specimens of cuitzeoensis have pale upper labials with dark lines on the sutures. Dorsal scale rows normally 21-19-17, ventrals 144–168, subcaudals 61–83, anal plate usually single (divided in AMNH 85145, a female 561 mm long). Apical pits present.
- Description of the Holotype: In its scalation this specimen agrees with The Species Model, except as follows: There are four postoculars on the left side of the head instead of the normal three. On both sides the lowermost postocular extends slightly forward beneath the eye. A small scale is wedged between the anterior temporal and the parietal on both sides of the head. The rostral is damaged as the result of abrasion while the snake was held in captivity for nearly four years.
- Scale rows 21-19-17, the first reduction resulting from the loss of row 5 at the level of ventral 75 on the left and ventral 72 on the right. Reduction to 17 rows occurs through the loss of row 4 at the level of ventral 93 on the left and ventral 87 on the right. Total ventrals 154, plus a single anal plate that bears a longitudinal groove across its left side; subcaudals 71 pairs. Tip of tail sharply pointed. Total length 1020 mm, tail length 229 mm, tail/total length = 0.225. A summary of scale counts for the entire sample from the Lago de Cuitzeo is in table 1. Several wild-caught specimens have incomplete tails.
- The presence of apical pits was amply demonstrated by an examination of a skin (the stratum corneum) that was shed by the holotype on January 28, 1965, while it was alive in captivity. A large part of the skin was preserved by affixing it in a spread-out position to a white parchmentlike sheet of paper shortly after it was cast. From this it was readily apparent that paired apical pits were present throughout the length of the body; they also extended onto the tail. They apparently occurred on all scales except those of the two lowermost rows on each side of the body, and were faint on scales of the third row. These observations were made within a day or two after the skin was shed. In July 2000 the pits had nearly disappeared when viewed with the naked eye. This was not surprising in view of the difficulty of finding apical pits in long-preserved specimens (Conant, 1961).
- Dorsum virtually uniform black, even after more than 35 years of preservation. Keels of the dorsal scales faintly marked with dark brownish black except on the two or three lowermost rows where they and the anterior portions of the scales of the lowermost row are marked with a slightly paler gray that was not visible in life (fig. 3A). Anterior half of each ventral scute black, posterior half dark gray flecked with darker gray to black; pale halves of ventrals more conspicuous toward posterior part of the body. The chin, throat, and infralabials are cream-colored; some black pigment encroaching on the upper edges of the infralabials, especially the 6th–10th. A few small black spots on the posterior part of throat; cream-colored area terminating rather abruptly at the level of the first enlarged scale anterior to where the ventral count starts. Ventral side of tail uniformly cream-colored, except that dark pigment encroaches slightly from the sides of the tail onto the posterolateral edges of the first 13 or 14 subcaudals, less so on the more posterior subcaudals. Most of the anal plate cream-colored, but with dark pigment at its lateral edges.
- Variation Among the Neonates: Total lengths of 18 neonates born in captivity to the holotype on September 13, 1964, varied from 244 to 264 mm, mean 252.1—10 males 244–264 mm, mean 255.8; eight females 244–253 mm, mean 247.5. Tail/total length in males 0.229–0.246, mean 0.236; in females 0.216–0.225, mean 0.221. Weights recorded on date of birth varied from 4.0 to 4.9 g, mean 4.55. A summary of scale counts for all the neonates is included separately in table 1.
- The general appearance at birth was black, but the head markings common to all races of Thamnophis eques were in evidence, including dark downward streaks on the sutures of otherwise cream-colored supralabials, pale preoculars and postoculars, and a pale crescent at the angle of the jaw (fig. 3). A trace of pale lateral stripes, but none of a middorsal stripe except for a short distance on the nape. Venters black along the anterior edges of the ventrals. Posterior halves of ventrals very dark bluish gray. The lower labials, chin, throat, underside of the tail, and the anal plate were cream-colored and unmarked.
- When the neonates were examined recently, after being preserved for over 35 years, faint traces of a pale middorsal stripe were evident as well as faint indications of dark lateral spots.
- Variation Among the Other Paratopotypes: This series of specimens varied in size from that of the larger neonates to adults approaching the length of the holotype. In life all adults were black except for whitish or cream-colored undersides of heads and tails. Juveniles were similar but they had pale supralabials with dark vertical sutures, a pale crescent at the angle of the jaw, and occasional traces of lateral stripes. In contrast, all adults had black supralabials. Several large adults also had small blackish spots on their throats, and black encroached from the dorsal surfaces of the tails onto the lateral edges of the anterior subcaudals. Keels on the dorsal scales in a few snakes were very dark brown instead of black. Tongue red or reddish, ranging from Vinaceous-Pink and Coral Red to Dragon's-blood Red; tips black. Eye: pupil black narrowly ringed by yellow in juveniles, darker shades in adults; iris dark brown or black. (All capitalized color names from Ridgway, 1912.)
- Food: Small fishes were so abundant in the Lago de Cuitzeo that the snakes never lacked for food. At least five species were involved (Robert R. Miller, personal commun.), viz.: Allophorus robustus, Chirostoma jordani, Goodea atripinnis, Xenotoca variata, and an unidentified member of the genus Skiffia. Examples of the first four were all palpated and removed from live snakes that had recently fed. The small Skiffia was partially decayed and wedged between rocks.
- At home we seined for small fishes in Taunton Lake in the New Jersey Pine Barrens and caught darters (Etheostoma fusiforme), small suckers (Erimyzon oblongus), and small sunfish (Lepomis gibbosus). Our captive Thamnophis eques cuitzeoensis caught the fishes as they were swimming in shallow glass dishes. Other snakes from Mexico's transvolcanic belt fed on the same three species of fish at our home base.
- A large male (AMNH 85141), 833 mm in length, had swallowed a hard, almost round, rubbery object that was revealed by dissection to be lodged in the stomach at the pylorus. The inedible object was dull yellow and measured 20 × 18 mm. When caught, the snake was as active as others collected on August 16, 1960.
- Behavior: Richard M. Blaney (personal commun.) visited Lake Cuitzeo in 1966 and 1979 and, as we had in earlier years, he found both Thamnophis eques and T. melanogaster and the small fishes on which they fed extraordinarily abundant. He made his field notes available to me. From them and subsequent conversations, I summarize the following: Several pregnant T. eques were observed sunning with the posterior loops of their bodies exposed, presumably warming the developing young. Both species of Thamnophis were seen hanging from holes between the rocks along the causeway, head in the water and catching fish as they swam by. Numerous T. eques were observed in open water floating in a single looped position, head submerged near the tail. Close observation revealed that the snakes slowly twitched and wiggled their tails as a lure to attract fish. Two were seen successfully catching small fish in this manner. Blaney was standing in water a foot or more in depth, and he remained motionless as he watched. The turbidity made visibility difficult, but he was close enough to be sure of what he was seeing. His field notes from Lake Cuitzeo concluded with, “While being photographed, specimens continued to display the tail in a manner similar to the behavior observed at the lake.”
- Blaney's findings explain the propensity of snakes of the eques complex to curl their tails. During our own photographic sessions, even in the studio, tail curling was frequent (see fig. 12), and we saw it in living eques from a number of far distant parts of the species' range. Pictures in the Conant collection include tails curled or partly so in snakes of the eques complex from the Mexican states of Chihuahua, Durango, Guanajuato, Jalisco, México, Michoacán, Nayarit, Tlaxcala, and Zacatecas. This suggests that using the tail as a lure for prey is widespread. Probably nowhere is it better perfected than at Lake Cuitzeo where the snakes are black, dorsally and ventrally, except for the whitish undersides of the head and tail. The contrast is the greatest in them. Blaney was apparently the first to observe the tail being used as a lure in this species.
- Similar use of the tail occurs in many kinds of snakes, notably the viperids. Juvenile members of the genus Agkistrodon, for example, have yellow tail tips that are raised and wiggled in imitation of an insect. Included is the cantil, Agkistrodon bilineatus, of Mexico and other parts of Middle America (Gloyd and Conant, 1990: 78).
- Our photo collection of the Thamnophis eques complex includes pictures of venters as well as snakes in normal positions. Curled tails are far more prevalent among the snakes lying upside down, suggesting another serpentine behavior, that is, moving the tail in the presence of a predator, ostensibly to distract attention from the more vulnerable head.
- A female eques, length 915 mm, from Chihuahua remained rigidly supine while being photographed except that every few seconds the tail was coiled in a different position. For a short time the anal opening was expanded and part of the cloaca exposed.
- LA LAGUNA DE YURIRIA Figure 4
- Material: Near the town of Yuriria (AMNH 96852–96863); 10 km west–northwest of Yuriria (AMNH 96864–96868, 118723, 118724); both localities in Guanajuato.
- Among these 19 snakes, all collected near the west and south sides of the lake, most were hidden beneath stones near the water's edge or in stone piles. Others were on the road near Yuriria, one alive and two dead. The majority were small (237–300 mm in length) and patterned with three well-defined pale longitudinal stripes, as in Thamnophis eques eques. They also bore dark lateral spots that varied in size and intensity, but were more prominent and darkest in larger specimens. In comparison, small snakes from the Lago de Cuitzeo were all strongly melanistic with body patterns suppressed and difficult to see. There were variations. AMNH 96864 (435 mm in length) was still well patterned, whereas AMNH 96866 (330 mm) was very dark and the stripes were obscure. For variation in specimens of comparable size see figure 4.
- The largest snake from Yuriria (AMNH 96852, DOR and 670+ mm in length) was jet black and unpatterned both dorsally and ventrally except for the underside of the head and tail, which were whitish and unmarked; it matched adults of cuitzeoensis. In addition to the specimens listed, we found an almost complete shed skin (AMNH 148804) in reeds along a small stream ∼10 km east of Yuriria. It was nearly a meter in length and was preserved by spreading it flat on a sheet of heavy paper. When compared with a similarly prepared shed skin from the type specimen of cuitzeoensis, the Yuriria skin was paler and almost patternless except for faint indications of three pale longitudinal stripes.
- Only a few of the snakes from Yuriria show dark ventral crosslines narrower but comparable with those exhibited by specimens of cuitzeoensis. In the latter melanistic serpents, the anterior half or less of each ventral scute is black, with the posterior portion very dark gray (see fig. 9A). In most snakes taken near Yuriria the dark ventral areas are narrow and confined to the bases of the ventrals.
- The samples we obtained of the eques complex at the Laguna de Yuriria had elements of the patterns and coloration of both the widespread Thamnophis eques eques and the geographically restricted T. e. cuitzeoensis, and they are considered as intergrades between the two subspecies.
- EL LAGO DE PATZCUARO
- Thamnophis eques patzcuaroensis, new subspecies Figures 5–7, 9B
- Holotype: AMNH 93937, a large gravid female from the lakeshore north of the town of Pátzcuaro, Michoacán, Mexico, collected August 7, 1964, by Roger Conant. Total length 1025 mm, tail length 242 mm, tail/total length = 0.236.
- Paratypes: AMNH 93936 same data as holotype; AMNH 93935 ∼11 km north of Pátzcuaro; AMNH 85123–85140, 87548, 87549, 88713 ∼5 km southwest of Quiroga; AMNH 93938–93957 (young born to holotype on August 29, 1964); AMNH 58230; LSUMZ 38558, 38559, 40864; UMMZ 93938, all from the Lago de Pátzcuaro.
- [Note: Virtually all material on which this review is based is from the AMNH collection, but information from a few adult male specimens from the Louisiana State University Museum of Natural Science (LSUMZ) and the University of Michigan Museum of Zoology (UMMZ) is included for two reasons: (1) my material is skewed in favor of females because all 15 snakes shot on mats of tules were of that sex, and (2) the male depicted in figure 7 has an aberrant ventral pattern. See caption for it.]
- Etymology: Derived from Pátzcuaro + adjectival-forming suffix –ensis (belonging to a place).
- Diagnosis: A large three-striped garter snake with the dorsal coloration often subdued and stripes frequently inconspicuous. Lateral stripes on rows 3 and 4 anteriorly; row 3 only posteriorly. Paired dark spots on each side of body between stripes that are best developed in young specimens, becoming less so with age; spots may virtually disappear in large females.
- The best diagnostic characters are on the ventral surfaces. The underside of the head and tail are yellow, often brilliant in life. Dark, often black, lines cross the anterior edge of each ventral. These may vary with age. They are usually narrowest in juveniles, but gradually increase posteriorly in width, darkness, and intensity. They collectively produce a series of dark and lighter crossbands throughout the length of the belly (see fig. 9B).
- Description of the Holotype: The scutellation agrees with that of The Species Model, with the following exceptions: The preoculars extend upward to and slightly involve the weakly developed canthus rostralis on both sides of the head. Three posterior temporals on right, the normal two on left. A small scale wedged between parietal and upper secondary temporal, much larger on right side of head than on left.
- Scale rows 21-(23)-21-19. The short increase to 23 results from the addition of a fifth row of scales from the level of ventrals 26–38 on the left and ventrals 34–39 on the right. The decrease from 21 to 19 results from the dropping of row 5 at the level of ventral 83 on the left and of row 4 at the level of ventral 81 on the right. Total ventrals 150; subcaudals 73 pairs. Tip of tail sharply pointed. Total length 1025 mm, tail length 242 mm, tail/total length = 0.236. A summary of scale counts for the entire sample from the Lago de Pátzcuaro is in table 2. Also see the commentary on the number of dorsal scale rows in the Discussion. In patzcuaroensis there are 23 rows, chiefly for short distances, in 55% of the population sample. Note: many wild-caught specimens have incomplete tails. Aberrations: anal plate grooved (not divided) in AMNH 85134 (female, 1010 mm) and 93943 (male, 243 mm, born in captivity). Anal partially divided in AMNH 85126 (female, 1013+ mm) and 93940 (female, 249 mm, born in captivity).
- In life, the holotype was dark, with the three pale stripes relatively inconspicuous, the paired dark spots between the stripes almost indiscernible (fig. 6). When it was examined 35 years later, considerable fading had occurred, and pattern features were clearly visible. The description of them is from the snake as it appeared in 1999. Coloration in life was recorded on January 9, 1965, as quoted below from my notes.
- The middorsal stripe involves the vertebral row of scales and most of the paravertebral rows. In the nuchal region all three rows are included in full. Farther posteriorly the outer edges of the paravertebrals are invaded by the dark lateral spots as far as the keels. The middorsal stripe narrows to a single row of scales on the head and terminates where it meets the parietal scutes. The lateral stripes are on scale rows 3 and 4 anteriorly, but row 3 only posterior to midbody. The small yellowish parietal spots are slightly elongated, and narrowly edged with black. A yellowish crescent two scales wide posterior to the temporals is followed posteriorly by a black semicrescent two or three scales wide. Two pairs of black spots are present on each side of body between the light stripes; the spots are relatively small, chiefly alternating with each other but variable in size and position.
- The ventral crosslines are faint for about the first 20 ventrals. They then become dark gray, almost black, and extend to the last two ventrals that are invaded in their centers by yellow matching the underside of the tail. The anal plate is mostly yellow, and a short groove is present anteriorly on the right side. The dark crosslines are stippled where they first begin, becoming solid afterward, and occupying the anterior third and more of each ventral. The posterior part of the ventrals are greenish gray and unmarked.
- Neonates:Born August 29, 1964, in a snakebag containing the holotype (AMNH 93937) in transit while returning from Mexico. Eighteen were alive; two others seemingly in perfect condition were dead (crushed under the weight of mother and siblings?). There were also five fairly well-developed embryos, one hard, the others in an advanced state of putrefaction.
- Measurements and color notes were made en route on the 20 young on September 3, 1964. Lengths of the 10 males varied from 217 to 268 mm, mean 250.9; of the 10 females 208–252 mm, mean 239.8. Tail/total length in males 0.237–0.253, mean 0.247; in females 0.221–0.245, mean 0.230. In the absence of a sensitive balance, no record of weights was made.
- Variation Among the Other Paratypes: Pattern notes were made on the 15 large females collected by shooting in 1960 (AMNH 85123–85137) as soon as they were preserved. All but one were dark. The dorsal stripes and spots could be made out only with difficulty. Ventrally, all but one were well marked. Dark crosslines occupied approximately the anterior third to half of each ventral. Most were solid black, but in a few snakes the crosslines consisted of dark stippling that slightly invaded the otherwise unmarked posterior pale green two-thirds or less of each ventral. The undersides of the tail and head were bright yellow. When reexamined in 1999, the preserved snakes looked much the same except for a small amount of fading. The pale snake (AMNH 85130, almost a meter in length) apparently lacked black pigment and it thus resembles the two males discussed below.
- Three adults of patzcuaroensis lacked conspicuous ventral crosslines in life, viz.:
- (1) AMNH 88713, a male 721 mm in length, collected August 15, 1960, hemipenes everted. The venter in life is depicted in figure 7. When examined in 1999, dark crosslines had appeared across approximately the anterior fourth of each ventral, a curious postmortem change. The faint dark longitudinal streaks on the midline of the belly were still visible. The following colors (capitalized colors from Ridgway, 1912) recorded from this snake in life are from my notes: “Middorsal stripe Dull Citrine. Lateral stripes Light Elm Green. Dorsal ground color Brussel's Brown. Below lateral stripe Sudan Brown. Belly Light Hellebore Green. Chin Mustard Yellow. Top of head dark olive-brown. Anal plate and underside of tail Straw Yellow.”
- (2) AMNH 58230, a male 896+ mm, collected at the lake by Rodolfo Ruibal on August 14, 1953. Despite its long period of preservation there apparently has been no change in pattern. The venter is still unmarked except for slight suggestions of crosslines.
- (3) AMNH 85130, a female, 996+ mm, shot August 15, 1960. This snake lacks black pigment and the undersurfaces have no dark markings.
- Other Paratypes: Most of the remaining specimens are small and they resemble the neonates in general. They are chiefly dark but with patterns readily visible in some, obscure in others. In several, the lowermost row of scales bears a continuous row of pale spots. The markings are best seen when the snakes are immersed in fluid. A female (AMNH 93936), 775 mm long, has all the pattern features strongly evident; like the holotype, fading in preservative apparently helped to bring them into sharp focus.
- Food: Snakes of this subspecies eat fishes, salamanders, and doubtless other aquatic organisms. I palpated two fishes from snakes that had eaten them and sent them to Robert R. Miller for identification. Under date of November 23, 1960, he wrote, “The two specimens for Pátzcuaro are a viviparous goodeid, Goodea luitpoldi, and one of the pescados blancos, Chirostoma estor. These two families (Goodeidae and Atherinidae) have undergone explosive speciation in the ‘Lerma System’ of lakes and streams; the genus Chirostoma and virtually all of the numerous goodeids are confined to that basin.”
- Chacón (1993) stated that the “fish fauna [of the Lago de Pátzcuaro] consists of 10 native and 4 introduced species …”. Smaller fishes and the young of all others are probably consumed by Thamnophis eques patzcuaroensis regardless of species.
- LA LAGUNA DE ZACAPU
- Thamnophis eques insperatus, new subspecies Figures 8, 9C
- Holotype: AMNH 87550, a female found run over on the highway 6 km southeast of Zacapu, Michoacán, Mexico, on August 22, 1961, by Roger Conant. A torrential rainstorm was in progress at the time, but it had been hot and sunny all morning. The snake was slightly decayed. The epidermis sloughed off when it was injected and preserved in formalin. The head and forepart of the body are flattened and burst open in two places. The posterior half of the tail is almost severed from the rest of the snake. The snout–vent length is 467 mm; the estimated total length 605 mm. There are no paratypes.
- Etymology: From the Latin insperatus, meaning “unhoped for; unexpected”.
- Diagnosis: A strongly checkerboarded garter snake with lateral spots black and alternated with pale grayish areas. Middorsal stripe present; lateral light stripes vaguely visible. The ventrals are black anteriorly, gray posteriorly (fig. 8).
- Description of the Holotype: The scutellation agrees with that of The Species Model, with the following exceptions: Four postoculars on right side of head, lowermost extending slightly forward beneath eye. Some cephalic scutes distorted or slightly displaced as a result of being pressed against the pavement by a passing vehicle. An example: a movement of the third supralabial on the left that seemingly makes it enter the orbit.
- No discernible apical pits; all apparently were sloughed off with the epidermis. Scales carinate throughout length of body and extending onto tail; keels weak on three lowermost rows of scales, possibly as a result of sloughing. Scale rows 21-19-17, reducing to 19 by the loss of the fourth row at the level of ventral 83 on both sides of the body. Reducing again to 17 by the loss of the fourth row at the level of ventral 109 on left and ventral 110 on right. Ventrals 155 plus a single anal plate. Subcaudals uncountable; posterior half of tail badly mashed. Tip of tail sharply pointed.
- Dorsum strongly checkerboarded with black “rectangles” conspicuous against a pale grayish background (fig. 8). Over a large part of the body each black rectangle involves three transverse dorsal scales and the length of a scale or a scale and a half longitudinally. There is frequent variation and there are no sharp 90° angles. The general effect is as though the dark spots commonly present between the pale longitudinal stripes in various species of Thamnophis had greatly increased in size and intensity at the expense of the stripes. The central stripe occupies the middorsal row of scales and the adjacent halves of the paravertebrals, but it is less conspicuous than in most other forms of garter snakes. Its pale scales are “dusted” with flecks of pale gray. Labials yellow and matching the yellow of the chin and throat. Black lines extend downward, chiefly anterior to the sutures between the labials, but they reach the commissure only on labials 7 and 8. The eighth supralabial is mostly black posteriorly. A partial yellow crescent marked with a few tiny black stipplings curves forward and upward behind the angle of the mouth. It is followed by a black area two scales wide that extends upward to the pale middorsal stripe. There are three rows of black rectangles on each side of the body. A narrow, more or less continuous black line extends along scale row 7 and then row 6 on the posterior half of the body.
- The undersurfaces match snakes from other lakes in the Cuenca de Michoacán. Anteriorly, each ventral is black but the dark pigment is not as wide as in patzcuaroensis. Posteriorly, the ventrals are gray but not as dark as in cuitzeoensis (fig. 9C). The underside of the tail in the holotype is yellowish cream.
- A close look at figure 8 reveals the pale middorsal stripe common to most populations of the Thamnophis eques complex. Less conspicuous are faint indications on scale rows 3 and 4 of lateral stripes. The many black markings appear to represent the dark spots between and beneath the stripes. The resultant drawing bears an almost uncanny resemblance to many of the nine faded, century-old AMNH specimens from Guadalajara. See the discussion about them at the end of the section on diluvialis. The snake depicted lost its epidermis through sloughing as the result of minor decay. Of all the forms of Thamnophis eques examined in this study of variation of Thamnophis eques in Mexico's transvolcanic belt, this is the only one not seen both in life as well as preserved. How regrettable that no other specimens of insperatus were obtained, and even more regrettable was my inability to return to Zacapu after 1965.
- LA CUENCA DE MICHOACAN
- EL LAGO DE CHAPALA
- Thamnophis eques obscurus, new subspecies Figures 10, 11
- Holotype: AMNH 87543, a moderately large male from the town of Chapala, Jalisco, Mexico, collected August 29, 1961, by Roger and Isabelle Hunt Conant. Total length 762 mm, tail length 179 mm, tail/total length = 0.235.
- Paratypes: All from or near settlements bordering the Lago de Chapala. Chapala AMNH 82032–82046, 87544, 87545, 91693–91695; Jamay AMNH 19544, 19545; Jocotepec AMNH 87546, 87547, 96841–96845; 10 km northeast of Sahuayo AMNH 93958.
- Etymology: From the Latin obscurus in reference to the faintness to complete absence of pale longitudinal stripes.
- Diagnosis: A virtually stripeless race of Thamnophis eques. Adults in life lacked pale longitudinal dorsal stripes (fig. 11). A few preserved for many years show faint traces of lateral stripes that now appear bluish. There is no indication of a middorsal stripe in any adult of the sample available. In the young, arbitrarily considered as all specimens less than 300 mm in total length, there may be traces in life of pale stripes immediately posterior to the head.
- The venter is grayish and the anterior edge of each ventral scute is black or dark gray (fig. 11). The resultant crossbanding is prominent, but the components are narrower than those on the venters of snakes from the Cuenca de Michoacán. The chin, throat, and underside of the tail are white and more or less unmarked. The anal plate is undivided and usually white in color, but it is dark in a few specimens.
- Description of the Holotype: Scutellation the same as that of The Species Model, with the following exceptions: Postoculars 4 on left side of the head instead of 3. Three temporals in second row (on left); 2 on right, but with a small scale about as large as the lower secondary temporal wedged between the anterior temporal and the parietal. Scale rows 21-19-17, reducing to 19 by the loss of the fifth row at the level of ventral 81 on the left and the loss of the fifth row at the level of ventral 77 on the right. Reducing again to 17 by the loss of the fourth row at the level of ventral 94 on the left and ventral 98 on the right. Total ventrals 158; subcaudals 73. Both hemipenes everted and of similar shape and appearance as in figure B in Rossman et al. (1996: 32). A summary of scale counts and other data for the entire sample from the Lago de Chapala is in table 3 (also see the Discussion). One of the 31 specimens, AMNH 93958 from near Sahuayo, was found DOR and was so badly damaged that few data could be recorded from it. Some of the others had incomplete tails.
- The holotype was preserved in the field, unfortunately just before unsuspected ecdysis. I had selected a large male as the type, but when I reexamined it in 2000 two soft spots had developed, probably because formaldehyde had not been injected evenly by the person who preserved it. Although the holotype had shed its scales (the stratum corneum) in part, many of the dorsal scales remaining in situ show evidences of apical pits.
- This is a dark brown snake that, in life, showed no signs of a striped pattern but, as in other long-preserved adults, there is a faint bluish gray line on each side of the body on scale rows 3 and 4 anteriorly and 2 and 3 posteriorly, where a prominent pale lateral stripe would have appeared in a living specimen of Thamnophis eques eques, for example. The top and sides of the head are dark brown, and the upper labials are dark gray and virtually unmarked. The two lowermost rows of scales have light centers, but these markings are weak in comparison with several other preserved adults.
- The anterior edge of each ventral is dark gray, almost black, and collectively is part of a long series of crosslines that show clearly through the overlapping part of the preceding scale. The unmarked posterior part of each scale is medium gray in coloration.
- The chin, throat, and infralabials are pale yellow, but the throat is invaded by dark pigment on the two scales preceding the first ventral. There are small black markings on about half of the infralabials. The underside of the tail is also pale yellow, but the outer edges of the first 25 subcaudals are slightly marked with pale brown.
- The anal plate is mostly pale yellow, but the dark pigment of the belly scales intrudes slightly on the right side of the body.
- Variation Among the Paratypes: This subject is discussed in part under the diagnosis of obscurus, but there have been a few notable postmortem changes. Most conspicuous is the development of a row of light spots on each of the two lowermost rows of scales in all of the large- and medium-sized snakes collected during the 1959–1965 period when we visited the Lago de Chapala. The edges of the scales in the two lower rows are dark, whereas the centers are pale, even white. The two light rows of spots are conspicuous in some specimens, less so in others. In the case of AMNH 91693, the two rows of light spots barely showed in life (fig. 11). When examined in 2000, after being preserved in 1959, the light spots were prominent throughout the length of the body, especially on the lowermost row.
- The two oldest specimens (AMNH 19544, 19545), preserved in 1919, have faded to dull gray. Most of their dorsal scales are edged with dark pigment, but the centers are pale. A faint suggestion of lateral stripes is gray rather than bluish.
- Juveniles in life were pale to medium brown dorsally and grayish ventrally. Faint markings appeared dorsally in the form of light stripes near the head. After a long period of preservation most of them now show evidences of both striping and spotting. A particularly well-patterned juvenile female (AMNH 91694), collected at the town of Chapala on July 15, 1959, has faint middorsal and lateral stripes extending rearward to the tail. There are also small brown spots in two longitudinal rows occupying the areas between the faint stripes, and measuring about one scale in width and two scales in depth. There is also a smaller row of brown spots below each lateral stripe. The chin, throat, anal plate, and underside of the tail are unmarked yellow.
- The coloration in life of three snakes from Jocotepec (AMNH 96842, 96844, 96845) was recorded, one soon after our return to base in 1965 and the others after they had been held in captivity for about a year. The following is a condensation of longer descriptions (capitalized color names are from Ridgway, 1912): Dorsal ground color olive. Lateral ground color Light Brownish Olive. Top of head olive. Labials Pistachio Yellow, sutures black. Belly Deep Bluish Gray-Green. Lines across ventrals black. Underside of tail Olive-Buff. Chin and throat pale greenish yellow. Eye: Pupil black ringed by bright yellow, iris olive. Tongue: Dragon's-blood red, tips black.
- Brumwell (1939) published a paper on variation in Thamnophis macrostemma (= T. eques) which included material from Chapala, lake or town not stated. The specimens he examined were from the Edward H. Taylor–Hobart M. Smith collection preserved in earlier years, and his descriptions of them matched those of mine after my snakes had been preserved for decades. According to Brumwell, all juveniles were strongly patterned and the adults had developed pale lateral lines. Neither was true when my snakes were alive. What an advantage I had in being able to study the snakes in life and again after there had been strong postmortem changes.
- Reproduction: At each of the other lakes in Mexico's transvolcanic belt where we collected series of specimens, gravid females were included. We kept them alive until the birth of their young, which were measured and weighed. No such females were found at the Lago de Chapala and thus no data are available on dates of parturition or number of young in obscurus. Several small specimens were obtained during July 1959 at the town of Chapala, some of them in storm sewers. The smallest was 244 mm in total length and another, with much of its tail missing, was 219+ mm. Based on measurements of newborn snakes from other lakes of the region, virtually all the juveniles we and others caught at Chapala were probably recent neonates. The largest specimen, a female also from Chapala, measured 1216 mm in length soon after it was preserved in 1959.
- Behavior: We made pertinent observations on behavior, some of which did not come into focus until the end of July 1965, when we left the Lago de Chapala for the last time. Others, notably Allen G. Brown, had watched the snakes for hours and he permitted me to record many of his observations in my notebook. In the company of the late Charles M. Bogert, Brown and two other students spent a few weeks during 1959 doing fieldwork in the area. We joined them for a few days.
- The town of Chapala is a resort on the lake roughly 40 km southeast of the large city of Guadalajara. A pier with benches and a ramada extended into the lake, and on weekends it was frequented by many people. Both observation and collecting were possible, the first by day, the second by night. I caught the holotype and two other eques by leaning over the edge of the pier at night and using my headlamp. The water was too low for me to reach it, but my wife, Isabelle, clung to my ankles, which gave me enough extra distance “to accomplish the impossible”, as she recorded in her diary.
- Brown (personal commun.) stated that it was normal to see the snakes swimming in the open water from the pier, sometimes far from shore, and even quite small ones moved about on the surface. He also said he watched several of the snakes swim toward the pier across wide stretches of open water. They would advance leisurely until they neared the pier, when they apparently detected motion and possible danger. They came right up to the pier at night. Brown and another student caught AMNH 82037, a female 654 mm in length, swimming far out in the open lake during daytime roughly midway between Chapala and the relatively distant Isla de Alacranes.
- The available sample from the Lago de Chapala of 31 obscurus contains 11 males and 20 females ranging from neonates to large adults, including a heavy-bodied female 1216 mm (almost 4 feet) in length. This is a small number in view of the fact that we visited the lake during the summers of 1959, 1961, and 1964, and were in residence at Jocotepec at its western end for almost the full month of July in 1965. We rented a cottage for a headquarters from which we visited the Lagunas de Atotonilco and Cajititlán and the remnants of the Lago de Magdalena, and we collected almost all the way to the Pacific coast near Tepic. While we were in Jocotepec, I obtained much useful information about the behavior of Thamnophis eques obscurus, almost all of it negative. During the early evening of each of the many nights we were in residence I waded in the shallow water at the edge of the lake looking for snakes. The relatively small Thamnophis melanogaster was abundant and found during every foray, 11 in one evening. It was also available by day, chiefly hidden among rocks or under clumps of vegetation near the water's edge. Thamnophis eques was conspicuous by its absence. I failed to obtain any of that species until the very end of the month when the level of the lake began to rise (about 15 cm in 24 hours on July 27–28). Meantime, a strong east wind drove water into areas that had remained dry all month. On the evenings of July 29–31 I found five obscurus, two of which were gorging themselves on small fishes that had ascended new channels into formerly dry territory. The following paragraph is condensed from my fieldnotes.
- A pattern has emerged. While the lake was low melanogaster was conspicuous, eques totally absent. Apparently, melanogaster is adapted to a riparian habitat that it exploits year round. Contrariwise, eques remains quiescent during the dry season. I had explored the landward side near Jocotepec to where there were weed-choked fields through which a machete would have been necessary to penetrate. The four eques I found nearby were along a narrow ditch where many fishes, which had worked their way upstream when the wind and waves propelled water inland, were trapped when it receded. Does the eques population go through some form of estivation during dry weather? At least at the western end of the Lago de Chapala?
- According to word received from Joseph Jordan of Jocotepec, our landlord for the cottage we occupied, Lake Chapala rose to a very high level after our departure on August 2, 1965. In a letter dated December 16, 1965, he admonished me, “When you make your next visit, do it in August or September, as the lake is real high and there are thousands of large snakes swimming wherever you look, and every little wash has several snakes in it. The lake, by the way, is at its highest level in twenty-one years, and my lower property is under five feet of water. It crossed the road in several places, but it is receding a little now.”
- The Jordans were a middle-aged couple and members of the large American colony in the towns of Ajijic, Chapala, and Jocotepec on the shore of the lake. They owned considerable property, including the weed-choked fields I could not penetrate. I had indoctrinated them soon after we first met in 1964 and had shown them several living examples of the two “water” snakes. I feel confident that Jordan's “thousands” of large snakes were Thamnophis eques obscurus.
- When the water was rising, Paul Ruthling collected two eques along the edges of flooded fields near Jamay at the eastern end of the lake on August 19, 1919. These are AMNH 19544 and 19545, about the first of which Ruthling wrote (personal commun.), “It was very large and fat and 42 inches long.” Snakes approaching or exceeding a meter in length from the Lago de Chapala were all large in girth and heavy bodied, as indeed are large snakes from other lakes of the general region.
- It is obvious that obscurus is a common snake in the Lago de Chapala despite the small size of our sample. Our experiences confirmed once again that “the collector must be in the right place at the right time.”
- A unique feature of the Lago de Chapala in 1959 was the presence of huge masses of water hyacinths of giant size covering the western half of the lake and completely halting all navigation. Manatees, Trichechus manatus, were introduced to eat the hyacinths and by 1965 the pestiferous plants were no longer a menace.
- Food: The following is quoted from correspondence with Robert R. Miller: “The tiny fish trapped by receding waters of Lake Chapala include 12 juveniles of Goodea atripinnis, 2 young of Chapalichthys encaustus, one young of Alloophorus robustus, and 6 young of Poeciliopsis infans. The first 3 belong to the family Goodeidae, the last to the Poeciliidae.” I sent the fishes to him in October 1965. Probably any fish small enough to swallow would be eaten. No evidence is available about other food such as frogs, salamanders, and invertebrates. Captives fed on frogs.
- What of the Future?: There have been many changes at the Lago de Chapala since we worked there in the 1960s. It is the principal water source for Guadalajara, Mexico's second largest city. Water also is drawn for the production of electricity. Pollution is acute. León and Escalante (1993) stated that the inflow stream, the Río Lerma, “drains a basin of almost 52,500 km2 receiving urban, agricultural, and industrial untreated waters.” The inflow to the shallow Lago de Chapala is highly polluted. Many native fishes have been locally extirpated and exotic species now constitute a large part of the catch. What effect are all these problems having on the population of Thamnophis eques obscurus?
- LAS LAGUNAS DE ATOTONILCO Y CAJITITLAN
- Thamnophis eques diluvialis, new subspecies Figures 10, 12, 13
- Holotype: AMNH 93966, a medium-large male from near Villa Corona at the north end of the Laguna de Atotonilco, Jalisco, Mexico, collected August 16, 1964, by Roger Conant. Total length 756 mm, tail length 175 mm, tail/total length = 0.231.
- Paratypes: Several gravid diluvialis gave birth to young after our return from Mexico. Each mother's number below is followed in parentheses by the numbers of her offspring. One female from Atotonilco and one from Cajititlán bore two litters, the second, in each case, about a year after the first. All localities are from the Mexican state of Jalisco.
- Laguna de Atotonilco: AMNH 93959–93978, 93979 (brood 93980–93984), 93985 (brood 93986–94005), 94006 (brood 94007–94029), 94030 (brood 94031–94047), 96806 (brood 96807–96816), 96817, 94006 (2nd brood 96818–96835).
- Laguna de Cajititlán: AMNH 96727–96734, 96736, 96737 (brood 96738–96773), 96774 (brood 96775–96805), 96736 (2 broods not numbered—18 slightly premature, 29 normal).
- Acatlán de Juárez: AMNH 94924, 94925.
- Near Estipac: AMNH 94964.
- Approximately 8 km west of Ixtahuacán de Los Membrillos: AMNH 91692.
- Playa de Santa Cruz: LSUMZ 23578, 23579, 24554–24558.
- Etymology: From the Latin diluvialis, in reference to the overflowing of the land by water when the habitat was created by the huge rises in level of the Lago de Chapala.
- Diagnosis: A large, conspicuously pale-striped snake in which the longitudinal middorsal stripe is a full three scales wide, involving the vertebral and paravertebral rows of scales and frequently small portions of the adjacent scales. Lateral stripes normally on rows 3 and 4 anteriorly, and rows 2 and 3 posteriorly. General dorsal coloration various shades of dark brown. Venter grayish, with a dark line across the anterior edge of each ventral scute. Chin, throat, and underside of tail yellow.
- Description of the Holotype: The scutellation agrees with The Species Model, with the following exceptions: The postoculars are 4 instead of 3, and the lowermost extends slightly beneath the orbit. On the right side of the head a small scale is wedged between the anterior temporal and the parietal.
- Scale rows 21-19-17, reducing to 19 by the loss of row 5 at the level of ventral 90 on the left and the level of ventral 87 on the right. Reducing again to 17 by the loss of row 4 at the level of ventral 116 on the left and ventral 117 on the right. Total ventrals 166; subcaudals 75. Tip of tail sharply pointed. Apical pits present, but difficult to find in this long-preserved specimen. Hemipenes not everted. Total length 756 mm, tail length 175 mm, tail/total length = 0.231. A summary of scale counts for the entire numbered sample from the Lagunas Atotonilco and Cajititlán and vicinity is in table 4. Many wild-caught specimens had incomplete tails.
- Dorsally, this is a dark brown snake strongly patterned at midbody by a wide longitudinal stripe of medium or orange brown. Lateral stripes normally on scale rows 3 and 4 anteriorly; rows 2 and 3 posteriorly. In life, the lateral rows were greenish, but during long preservation they have changed to bluish. A double row of dark brown spots between the stripes on each side of the body that are inconspicuous against the general dorsal ground color of the dorsum. A row of similar dark spots below each lateral stripe. Top of head dark brown and unmarked, except for a faint, very small pair of parietal spots.
- The anterior edge of each ventral is dark gray, approaching black, and collectively is part of a long series of crosslines that show clearly through the overlapping part of the preceding scale. The unmarked posterior portion of each scale is medium gray in coloration.
- The chin, throat, and lower labials are yellow, but the throat is invaded by dark pigment on the scale preceding the first ventral. Most of the sutures between the infralabials are black, but in a few cases the dark pigment is lacking. The underside of the tail is brighter yellow than the chin and throat. The single (undivided) anal plate is colored the same, except for its lateral edges. It bears slight traces of the coloration and pattern of the ventral scutes.
- Variation Among the Paratypes: In life, these were brown snakes, varying from pale to dark brown in general appearance, except for the three pale longitudinal stripes that were usually in strong contrast with the more somber hues of the rest of the dorsum. With the snake in hand, paired and alternating dark spots between the pale stripes were evident, but in photographs (figs. 12, 13) they were scarcely noticeable.
- After being in preservatives for more than a third of a century, there have been many changes in color pattern, drastic in some specimens, minor in others. The broad (three scales wide) middorsal stripes may be in weaker or stronger contrast with the adjacent dark dorsum. The dark spots are visible in all specimens and they stand out in striking fashion in a few. The two lowermost rows of dorsal scales may show dark spots or pale rounded ones. The top of the head is dark brown, unmarked except for tiny parietal spots.
- Dark lines across the anterior edge of each ventral. Remainder of belly usually grayish yellow; greenish or bluish in others. Undersides of chin, throat, and tail unmarked pale yellow. Anal plate similar, but dark pigment may encroach slightly from the sides.
- Neonates in life were more or less replicas of the adults, except that they were paler. After long preservation there were changes, notably fading and a concomitant strengthening of patterns. The paired dark spots between the lateral stripes became conspicuous. Pattern and color descriptions of two specimens are as follows:
- (1) AMNH 94004, 228 mm in total length, a member of a litter of 20 born November 9, 1964; female parent (AMNH 93985) collected at the Laguna de Atotonilco on August 16, 1964. The paired dark spots are prominent and some of them are conjoined with their neighbors. Similar but smaller dark spots are continuous below each lateral stripe. A series of narrow dark lines is present where the dorsal and ventral scales meet and these form a continuous dark line in part. The dorsal stripe widens from a width of 3 scales to 5 on the nape and then narrows to a single scale where it meets the parietals. The result is a heart shape posterior to the almost black head. The belly is similar to that of adults. The chin, throat, and underside of the tail are pale yellow.
- (2) AMNH 96800, total length 244 mm, from a litter of 31 born November 21, 1965, to a female (AMNH 96774) from the Laguna de Cajititlán collected July 28, 1965. Similar to the juvenile from Atotonilco, but the dorsal stripe widens only slightly on the nape. An intermittent dark line at the juncture of the dorsal and ventral scales forms part of the lowermost row of dark spots.
- Reproduction: Unlike our experience with obscurus at the Lago de Chapala where we found no gravid females, eight diluvialis in that condition were collected, five at Atotonilco and three at Cajititlán.
- Dates of collection ranged from July 14 to August 16. Dates of birth of young were from September 7 to November 26. Late dates probably reflect the interruption of normal development of the offspring. The gravid females were kept inert in bags all through the long drive from the lakes to our home bases in and near Philadelphia.
- The number of young in a brood varied from 5 to 36. The total lengths of the offspring were 171–244 mm, and the weights immediately after birth 2.0–4.7 g. One female from each of the two lakes, and which had been caged with one or more males, bore a second litter about a year later. In all, there were 207 young in a total of 10 litters, one litter slightly abnormal. Scale counts are available for most of these and are summarized separately in table 4.
- A large female (AMNH 96736), 1015 mm in length, collected July 28, 1965, at the Laguna de Cajititlán, gave birth to two litters of young in captivity. The first, born September 5, 1965, and numbering 18, was slightly premature. The yolk sacs in all were completely free from the bodies, except for a narrow cord. None of the young showed any indication of crawling, but they extended their tongues, flattened their bodies, and even struck defensively. All hemipenes were inverted, with none visible externally. They were all flabby and did not preserve well. The same snake, caged for a while with a male, bore a normal litter of 29 young on July 26, 1966. Only the adult female was numbered. No scale counts were made on the young. The abundance of data available from neonates born to other females from Cajititlán was more than adequate.
- To analyze all 10 broods would occupy an inordinate amount of space, but details are given below for the components of the largest brood, with information on sizes and weights.
- A gravid female (AMNH 96737) measured 1031 mm in length and weighed 276.5 g immediately after the birth of her 36 young on November 17, 1965. She was collected on July 28, 1965, in the Laguna de Cajititlán. She was confined in a cloth bag on a pile of foam rubber in a storage space beneath the bed in our camper with a number of other gravid snakes. There she remained as we zigzagged across Mexico and then home, where we arrived 17 days and almost 4000 miles later. I inspected our live collection almost daily and each snake was given a chance to drink every few days. The mother ate sporadically at our home base, chiefly on small Rana pipiens. My notes, written on the day the young were born, state, “She is thin and spent but still vigorous, pugnacious, and fairly heavy.”
- Among the 36 young (AMNH 96738–96773), 20 were males and 16 females. The males, after they were preserved and sexed by dissection, measured 214–233 mm in length, mean 224; the females 203–236 mm, mean 219. The live neonates were weighed but not sexed on November 19, 1965. Individual weights varied from 3.4 to 4.7 g, mean 4.0. Several of the tails of both sexes were slightly curled at birth. Two infertile ova were passed with the young.
- Color notes were made after the young were euthanized and before they were preserved. Capitalized color names are from Ridgway (1912). The dorsal ground color was dark brown (Mummy Brown); the lateral coloration was paler (Dresden Brown). The middorsal stripe was an orange-brown (Buckthorn Brown) anteriorly, but it changed to a dark reddish brown (Prout's Brown) for most of its length. The lateral stripes were light green (Deep Lichen Green). Top of head darker than ground color. Chin and throat pale yellow (Straw Yellow); underside of tail similar. Eye: pupil black bordered by yellow; iris Olive-Brown. Tongue: Dragon's-blood Red at base, but becoming Brick Red anteriorly; tip black.
- Occurrence at Guadalajara: Despite a search for one, no map is at hand to show the maximum extent of the lake or lakes that came into existence when the Lago de Chapala rose almost 200 m above its present level and spilled over (Clements, 1963). How far north did it go? Did it reach the area of the present city of Guadalajara, which is now only about 25 km north of the Laguna de Cajititlán? The Atlas Goodrich Euzkadi (1964) shows changes in altitude in color throughout Mexico, and its map 17 indicates that low areas are currently present from Cajititlán all the way to Guadalajara so, presumably, it was possible for the flood waters to extend that far northward even though it was a very long time ago and may have been influenced by tectonic events.
- There is some evidence that it may have extended at least that far. In the herpetological collection of the American Museum of Natural History there are nine specimens from Guadalajara (AMNH 3199–3202, 3206, 3207, and 3438–3440) that were collected a century ago (1899–1901) by L. Diguet, the Duke of Loubat, when the city was much smaller than it is today. All of these snakes are still in good condition, but they have faded and only the black pigment, chiefly that which composes the dark spots between the pale stripes, is conspicuous. The dark spots, which scarcely show in the accompanying illustrations (figs. 12, 13), were visible when the live snakes I collected were in hand during 1964 and 1965. After more than 35 years of preservation, some have changed rather slightly, whereas others have faded, two of them so much that they somewhat resemble the century-old snakes.
- An examination of the nine Guadalajara snakes reveals that the middorsal stripe is three scales wide as in specimens of diluvialis, but occasional small amounts of darker adjacent pigment invade the paravertebral scales. In six specimens, the dark spots are prominent; they are less so in the other three. All are of relatively large size, ranging in length from 539 to more than 800 mm. Tentatively, I place these nine old snakes in diluvialis.
- EL LAGO DE MAGDALENA
- Thamnophis eques scotti, new subspecies Figures 14–18
- Holotype: AMNH 96691, a female from near Magdalena, Lago de Magdalena, Jalisco, collected July 7, 1965, by James D. Anderson, Robert Giacosie, and Roger Conant. Total length 819 mm, tail length 191 mm, tail/total length = 0.233. The holotype gave birth to 18 young on July 31, 1965.
- Paratypes: Several gravid scotti, in addition to the holotype, bore young after our return to base. Each mother's number listed below is followed in parentheses by the numbers of her offspring; other numbers are of individual specimens: AMNH 87496–87529, 94048, 94049, 94050 (brood 94051–94058), 94059 (brood 94060–94077), 94078 (brood 94079–94091 removed by dissection), 94902–94923, 96691 (brood 96692–96709), 96710 (brood 96711–96726).
- Etymology: Named for Norman J. Scott, Jr., who might have been a coauthor of this paper if his superiors had permitted him to remain in Albuquerque. A few years ago, he visited several of the lakes of Mexico's transvolcanic belt and confirmed for me that the snakes were still actively present.
- Diagnosis: A large, usually three-striped garter snake, but subject to wide variation. A majority, in life, were relatively pale in coloration, with the ground color between the lateral spots only slightly darker than that of the middorsal stripe. Others were dark, with the body color in strong contrast with the central stripe. The latter normally involves three to five rows of scales, but it may vary from zero to seven scales wide. Pale parietal spots are tiny or absent. No dark line paralleling each side of the pale middorsal stripe as in T. e. carmenensis. The tail spine is usually short and not part of a long scale as in many forms of T. eques.
- Description of the Holotype: In its scutellation this specimen agrees with The Species Model, except as follows: The postoculars are 4 instead of 3, with the lowermost on each side extending slightly beneath the eye. A small scale is wedged between the temporals and the parietal, larger on the left than on the right.
- Scale rows 21-19-17, reducing to 19 by the loss of row 5 at the level of ventral 82 on the left and ventral 78 on the right. Reducing again to 17 by the loss of row 4 at the level of ventral 105 on the left and ventral 103 on the right. Total ventrals 150; subcaudals 73. Tip of tail bluntly pointed. Apical pits present, but difficult to find in this long-preserved specimen. Total length 819 mm, tail length 191 mm, tail/total length = 0.233. A summary of scale counts for the entire cataloged sample from the Lago de Magdalena is in table 5. An exceptionally large number of wild-caught specimens have incomplete tails.
- This is a “blonde” snake and a good example of the way I remember a majority of the specimens of scotti in life. It may be described as follows: Dorsal coloration yellowish brown, middorsal stripe 3 scales wide and a little paler than ground color between stripes. Lateral stripes pale greenish gray on scale rows 3 and 4 anteriorly, rows 2 and 3 posteriorly. An irregular, relatively inconspicuous double row of black spots between the dorsal and lateral stripes; a similar row on scales of first row. Top of head medium brown with several slightly darker, scarcely visible, more or less longitudinal streaks. Pale parietal spots lacking.
- Anterior edge of each ventral scute marked with stippled pale gray; posterior part of each ventral pale greenish gray. Posterior three-fourths of the ventrals bear pale yellow spots or streaks at the center of their anterior edges that collectively suggest a narrow intermittent yellow midventral line.
- Supralabials pale gray. Infralabials, except along or near sutures, yellow. Chin, throat, anal plate, and underside of tail also yellow, unmarked.
- Variation Among the Neonates: Total lengths of 18 neonates born in captivity to the holotype (AMNH 96691) on July 31, 1965, varied from 193 to 232 mm, mean 220.6—12 males 216–232 mm, mean 225.6; 6 females 193–222 mm, mean 210.8. Tail/total length in males 0.244–0.255, mean 0.248; in females 0.229–0.243, mean 0.235.
- A careful inspection of the 18 neonates revealed that they collectively bridged almost the entire range of color and pattern variation in the large adult sample of scotti available. In the latter, the width of the middorsal stripe normally varies from one to five scales (a few have no stripe and one has such a broad stripe that it measures almost seven scales wide). In the neonates the central stripe varies from one to five scales wide regardless of sex. The paired yellowish parietal spots are tiny or missing, as in the adults. Most of the neonates tended to be pale, whereas in others, where the dark spots between the pale lateral stripes are large and dark, they probably would have grown into the dark morph of scotti illustrated in the upper half of the color plate (fig. 18).
- The head markings of the neonates differ from those of the adults. The posterior half of the preocular and the anterior half of the postocular are whitish. Immediately posterior to the angle of the jaw the whitish color of the throat extends upward for the height of three scales to form a pale, more or less triangular marking at the rear of the head on each side. Posterior to that marking is a dark bar about three scales wide extending diagonally forward to meet the parietals. Top of head dark brown. A few of the neonates have slight variations from the pattern described.
- Among the many snakes collected at the Lago de Magdalena, two of similar size, taken July 7, 1965, and stored in isopropanol rather than ethanol, have retained their coloration and pattern so that they look much as they did in life. They are the holotype (AMNH 96691) and AMNH 96710. They both still agree rather closely with detailed color notes I made on them late in 1965, using the color swatches of Ridgway (1912). The differences involving the two types of preservatives are pronounced. AMNH 96710 would have been chosen as the type, except that a large part of its tail is missing, probably bitten or broken off by a turtle, heron, or other predator. She bore a litter of 16 young on October 11, 1965, and detailed data from that litter, including weights and color notes recorded shortly after birth, are condensed herewith.
- The 16 young of AMNH 96710 include 7 males and 9 females measuring, collectively, 193–217 mm in total length, mean 207.7; weights 2.8–4.0 g, mean 3.4. The head patterns among snakes of this brood are slightly different from those of the young born to the holotype (AMNH 96691). The small dark bars immediately posterior to the head run crosswise and are separated from the parietals instead of extending diagonally forward to meet those large scales. Pale parietal spots present, but faint and tiny.
- The dorsal ground color in life was medium dark brown (Dresden Brown), and the lateral ground color was yellowish brown (Buckthorn Brown). In some of the young snakes the middorsal stripe matched the darker shade of brown; in others they matched the paler one. Top of head dark brown. Supralabials, preoculars, and lower postoculars bright yellow (Wax Yellow). Chin and throat paler (Massicot Yellow). Underside of tail even paler (Olive Buff). Venter yellow with a slight greenish tinge (Reed Yellow). Eye: pupil black ringed by orange-yellow; iris brownish olive. Tongue: Coral Red; tips black. Capitalized color names from Ridgway (1912).
- Variation Among the Paratypes: In life, most specimens were relatively pale and the middorsal stripe was more or less similar in hue with the coloration between the dark spots on the sides of the body. In essence, they more or less matched the snake portrayed in the upper half of figure 17. Other specimens were dark, with the middorsal stripe in sharp contrast with the adjacent parts of the body as in the upper figure on the color plate (fig. 18).
- A recent examination of all the snakes from the Lago de Magdalena revealed many postmortem changes. In a great many there was a darkening, mostly on the sides of the body, but also frequently involving the middorsal stripe. Especially noticeable was a change in the upper labials from a pale gray in some to black in others. In life, the supralabials were usually pale gray to yellowish (figs. 17, 18). Other postmortem changes involved the lower sides of the body. The lateral stripes had become bluish and the two lowermost rows of scales had light centers in dark scales, some black, resulting in continuous rows of light spots. In some that had lost many scales (the stratum corneum), the sides of the body were pale in color.
- Both in the field and when snakes were euthanized after periods of captivity they were thoroughly injected with formalin for hardening. Almost all were then transferred to ethanol, in which preservative they darkened, some of them considerably.
- Reproduction: The gravid females we took home with us gave birth to their young, and some of the mothers that were retained alive with captive males had additional offspring a year or more later.
- Five broods of young were born in captivity from females collected at Magdalena. Dates of collection were July 7 and August 18. Dates of birth ranged from July 31 to November 10. In the case of the latter date, the apparently full-term young were removed by dissection when the mother, held captive in my office at the Philadelphia Zoo, was euthanized after she strained for several hours but was unable to extrude her young.
- The number of young in a brood varied from 8 to 18. The total lengths of the offspring were from 186 to 251 mm. Not all the young were weighed, but those that were varied from 2.3 to 5.5 g. Scale counts for most of these are summarized separately in table 5.
- One large heavy-bodied female, AMNH 94050, collected August 18, 1964, near Magdalena had an unusual record. From her impregnation in the wild she had eight young (AMNH 94051–94058) on September 1, 1964. She was caged with a male and she bore 14 additional young on July 18, 1967. Because so many other neonates were available, the 14 were not tagged, but they were preserved with their dam. She bore another litter on July 26, 1968, that was discarded. The male died during June 1968. On October 17, 1969, the female passed three young, one alive and two full term but dead, probably a case of delayed fertilization, at one time called amphigonia retardata. The female died on October 24, 1971, after living in excess of seven years in captivity. More than half of her tail was missing and she bore a large, well-healed, protuberant rounded scar 30 mm in diameter and 13 mm in depth on the right side of her neck, less than a head length posterior to the angle of the jaws.
- Remarks
- EL VALLE DE MEXICO
- LA LAGUNILLA DEL CARMEN
- Thamnophis eques carmenensis, new subspecies Figures 18–20
- Holotype: AMNH 93842, a female from near El Carmen, Tlaxcala, collected July 8, 1964, by Roger Conant. Total length 691 mm, tail length 142 mm, tail/total length = 0.205. The holotype gave birth to 14 young on July 20, 1964.
- Paratypes: Several gravid carmenensis, in addition to the holotype, bore young in captivity. Each mother's number listed below is followed in parentheses by the numbers of her offspring; other numbers refer to individual specimens: AMNH 93818–93841, 93842 (brood 93843–93856), 93857 (brood 93858–93875), 93876 (brood 93877–93887), 93888 (brood 93889–93900), 94926–94959.
- Etymology: Derived from El Carmen + the adjectival-forming suffix –ensis (belonging to a place).
- Diagnosis: A garter snake of medium size characterized by a narrow pale middorsal stripe. It involves the vertebral and paravertebral scales, but black pigment normally encroaches from the sides to include the keels on the paravertebral scales or even beyond them. The pale central stripe is bordered by a continuous black line a scale or two in width. The paired dark lateral spots are discernible and their upper edges are fused with the black line bordering the middorsal stripe. Many specimens exhibit a tendency toward melanism; others, probably those that had recently passed through ecdysis, have the pale stripes vividly evident against the darker parts of the body. The pale lateral stripes occupy scale rows 3 and 4 anteriorly and 2 and 3 posteriorly, but small black flecks invade the edges so broadly as to reduce the thickness of the stripes. The lowermost rows of scales are punctuated with black spots.
- The portions of both the preoculars and postoculars closest to the orbit are conspicuously whitish or yellowish. A black crescentic mark about two scales wide across the angle of the jaws is preceded by a pale crescent one or two scales wide extending upward for the length of three or four scales. Belly pale bluish or greenish, the black line at the anterior end of the ventrals faint in some, conspicuous in others.
- Description of Holotype: In its scutellation this snake agrees with The Species Model, except that the postoculars on the right are two instead of three. The two lower ones are fused into one long vertical scale.
- Scale rows 21-19-17, reducing to 19 by the loss of row 5 at the level of ventral 82 on the left and the level of ventral 76 on the right. Reducing again to 17 by the loss of row 4 at the level of ventral 111 on the left and ventral 110 on the right. Total ventrals 155; subcaudals 68. Tip of tail sharply pointed. No apical pits found in it or other long-preserved specimens. Total length 691 mm, tail length 142 mm, tail/total length = 0.205. A summary of scale counts from the entire numbered sample from La Lagunilla del Carmen is in table 6. Only four wild-caught specimens had incomplete tails. Other than humans, there apparently were few predators.
- General appearance, both in coloration and pattern, very similar to the snake shown in color in the lower part of figure 18. The dorsal surface consists of a variety of longitudinal areas that differ in coloration. Most prominent is the bright yellow middorsal stripe. It is narrow, involving the vertebral row of scales, but only a small portion of the paravertebral ones. Black pigment extends upward to encompass the keels on the paravertebrals. The black line parallelling the yellow middorsal line is virtually two scales wide because it truncates the tops of the lateral dark spots, although less conspicuously toward the rear of the body. In comparison with other races of Thamnophis eques, the lateral dark spots are small and concentrated largely against the longitudinal stripes. They leave a patternless area between them that is dark olive-green. Lateral stripes olive-yellow, occupying scale rows 3 and 4 anteriorly and rows 2 and 3 posteriorly. Lateral stripes flecked with black, especially along their lower edges.
- Top of head brownish olive. Middorsal stripe widens to three scales on the nape and then reduces to a single scale. Pale parietal spots, each surrounded by black. Both preocular and postocular scales with pale pigment. Upper labials pale olive-yellow, sutures black. Chin and throat, including infralabials, yellow, extending to about the fifth ventral and then becoming greenish gray that darkens slightly toward the tail and continues onto the first 10 or 12 subcaudals. It then changes to dull yellow.
- Variation Among Neonates: Total lengths of 14 neonates born in captivity to the holotype (AMNH 93842) on July 20, 1964, varied from 207 to 227 mm, mean 218.3—8 males 215–227 mm, mean 221.1; 6 females 207–220 mm, mean 214.5. Tail/total length in males 0.223–0.236, mean 0.229; in females 0.203–0.216, mean 0.212. The young were born in Mexico and I euthanized and preserved them the following day in the field.
- In these young the three longitudinal stripes are conspicuous and so are the pairs of dark spots between them. A black line borders the pale middorsal stripe and the upper lateral spots are fused with it. The lower dark spots border the upper edge of each pale lateral stripe. The lowermost rows of scales are flecked, spotted, or vertically barred with black. The venter is whitish to dull gray, with crosslines visible. The chin, throat, and most of the underside of the posterior part of the tail are yellow. The oculars are chiefly white. All have very small yellow, paired parietal spots.
- Four other litters of carmenensis were born in captivity on dates ranging from June 24 to September 19. The numbers of young in the litters were 11, 11, 12, and 18; the shortest individual (a female) measured 163 mm in length, the longest (a male) 218 mm. The second litter of 11 was born presumably on July 24, 1965, while we were in Mexico. The female parent was the holotype of carmenensis, which was caged with a male in my office at the Philadelphia Zoo. The reptile keeper who made the daily inspection found the litter dead and not in prime condition. He froze the juvenile snakes pending my return. They are now AMNH 96836–96840 and 148799–148803. One was so poor that it was discarded.
- The 12 young of AMNH 93888 were weighed soon after birth. They varied from 1.2 to 1.6 g, mean 1.4. They weighed considerably less than neonates from other populations of the complex.
- On August 10, 1965, we collected 36 carmenensis (34 preserved, 2 small ones escaped), among which the great majority were presumably neonates. The largest born in captivity was 227 mm long. Among the wild-caught specimens, 24 were 227 mm or less. The shortest, a male, was 172 mm.
- In coloration and pattern, all captive-born and wild-caught neonates were similar to those born to the holotype and described in some detail above. Ample allowance had to be made, however, for ecdysis. The baby snakes apparently grew gradually duller until they once again shed their skins (the stratum corneum).
- Variation Among Other Paratypes: Neonates constitute a majority of the paratypes. Fifty-five were born in captivity and 24 of those collected are of neonate size. Thus, about 65% of the material from the lagunilla has already been reviewed in the section above.
- The remaining paratypes in general are similar. The smaller specimens are darker, the larger ones more conspicuously marked. The dark lateral spots vary in intensity. In many, the upper row is virtually fused with the black stripe parallelling the yellow middorsal stripe. Pale parietal spots, small to tiny, are present as in the neonates, but they are narrowly margined with black in the larger snakes. AMNH 93818, a female 646 mm in length, has the dorsal surface of the head, including the supralabials, dark and unmarked; on its venter the dark crosslines are strongly evident. These lines vary. They are visible in some specimens, but scarcely show in others.
- The dorsal ground color in life was olive (Buffy Citrine to Sepia). Middorsal stripe Amber Yellow or Wax Yellow. Top of head dark olive. Lateral stripes Strontian Yellow to Yellowish Citrine. Venter greenish (Veronese Green, Kildare Green, or Rainette Green). Chin, throat, and underside of tail Barium Yellow to almost Light Dull Green-Yellow. Eye: pupil black ringed by orange-yellow; iris brownish olive. Tongue: Coral Red, tips black. Capitalized colors are from Ridgway (1912).
- Size: Thamnophis eques is a large garter snake. In every sample examined from single localities and which was sufficiently abundant to provide a good cross-section of size, coloration, and pattern, one or more individuals exceeded a meter in length. AMNH 82039, a female from the Lago de Chapala, the largest specimen on record, is 1216 mm long.
- The population from the Lagunilla del Carmen, on the contrary, is dwarfed. Among the 66 specimens collected from that small body of water, the largest female was only 724 mm long; the largest male 693 mm. From all Mexican localities examined, including those beyond the transvolcanic belt, the largest specimens are females. The longest males fall within the 900 mm bracket and many, especially from the Lago de Magdalena, approach a meter in length. One from the Lago de Pátzcuaro, UMMZ 98938 (from the Museum of Zoology of the University of Michigan), measures 980+ mm. It has only 48 subcaudals and, if the missing scales were present, it would have surpassed a meter.
- The small size of specimens of carmenensis creates the illusion that their heads are exceptionally small. To test that possibility, I measured numerous heads of it and other eques subspecies using the Rossman formula (Rossman et al., 1996: 24). Under that system, the head length from the anterior tip of the rostral to the angle of the jaws is divided by the snout–vent length. The results demonstrated that the heads in carmenensis are proportionately the same length as in the other races of Thamnophis eques.
- Behavior: The young exhibit a strong tendency to arrange themselves in coils, even immediately after birth. The snakes in one litter, when removed from the terrarium in which they were born, were coiled in all cases—on the flat bottom, between their water dish and the side of the terrarium, and on the cork bark provided for their shelter. The head often would be hidden either toward the center or under a loop of the body (fig. 20). Many retained this attribute throughout the length of their captivity and regardless of size.
- When picked up to be photographed, they might be lying in more or less a straight line, but when on the posing table they soon coiled. The photo of the venter (fig. 20, lower), as in the cases of all pictures of undersurfaces, was obtained by restraining the snake inert in an upside-down position.
- Neonates were placed in small safety match boxes to be weighed; afterward, when the box was overturned to free the animal, the coil was retained whether right side up or not.
- The habit of coiling may have survival value. Young in such positions were noted three or four times as we wandered over the shallow habitat, and small boys found two I failed to see. Would a predator overlook an inert coil?
- Only one snake, an adult female, among several of various sizes tested, coiled its tail the way specimens of other subspecies did as, for example, the male diluvialis depicted in figure 12.
- Food: Rana spectabilis was surely the principal food of adult Thamnophis eques carmenensis, and the tadpoles and metamorphs for the young snakes. I collected four voucher frog specimens in 1964 (AMNH A-73392–73395), measuring 33.9–43.9 mm in snout–vent length. I also obtained a transforming one (AMNH A-75255) in 1965 that was being eaten by a snake (AMNH 94931) only 299 mm long. It had begun at the frog's snout and engulfed the left front leg, but it was unable to advance any further. The frog retained a long tail, 40 mm measured ventrally.
- The frogs were abundant in the lagunilla, except in the highly alkaline portions of its lower ends. Two other potential food animals also were present. During our 1965 visit, I did some seining and caught a few small goldfish, Carassius auratus, that I preserved and which were confirmed by Robert R. Miller. They doubtless had been introduced.
- Alcocer et al. (1997: 271) wrote that ambystomatid salamanders are absent in the springs. I failed to find salamanders, but one of the snakes (AMNH 94926) did, not far from the actual ojo. It had half swallowed a salamander when I caught it on August 10, 1965. Because I feared I might damage them, I did not separate the two animals, but permitted the snake to finish engulfing its prey. Several hours later, I euthanized the snake and used a long narrow-gauge needle to inject reptile-strength formalin into its body cavity and also that of the salamander. Back at my home base, I removed the amphibian by dissection and stored it in weaker formalin. Eventually, it was deposited in the American Museum of Natural History where it was cataloged as Ambystoma velasci (A-135815). Total length, measured in April 2001, 114 mm; snout to rear of anal slit 68.7 mm. No indication of external gills. Costal grooves 12, including an axillary and inguinal. Many ill-defined grayish spots on a pale gray background. See Shaffer and McKnight (1996: 419) for a map showing the distribution of Ambystoma velasci.
- Orientation: Alcocer et al. (1997) published a review of the large endorheic basin at the eastern end of the Mexican plateau. They referred to it as the “Oriental”, but it is the equivalent of the Llanos de San Juan indicated on figure 1 of this paper. Much of the area was once occupied by lakes, one of which bears the name of Totolcingo or El Carmen. They have been gradually drying up because of overextraction and channelization of springs for human use. In May 1933, rain water persisted for only one month, and since then “Totolcingo Lake has remained dry.”
- Alcocer et al. (1998) quoted from a government document (Anonymous, 1982, translation) which stated that “the Oriental basin is located almost 100 m above Mexico City, so its extensive ground-water resources are being gravity-transported to satisfy Mexico City's requirements.” The altitude for El Carmen is given as 2340 m above sea level.
- Javier Alcocer, the authority on the “Oriental”, wrote (personal commun.), “Fortunately there are other loci that could serve to preserve aquatic fauna in the area. Not long ago I visited the railway station named Manantiales [‘springs’] where there is at least one large spring left. Also, there are small scattered veneers throughout the lower portion of the basin where El Carmen playa intermittently formed. El Carmen is not an ephemeral lake yet …”. Unhappily, the map published in 2000, as mentioned above, indicates that there is no longer water in the lagunilla where I obtained a large series of snakes during the 1960s.
- Remarks
- LA LAGUNA ALCHICHICA
- DISCUSSION
- Identification
- Tables of Scutellation
- Future Exploration
- ACKNOWLEDGMENTS
- SOURCES OF MAPS AND ATLASES
-
FIGURES & TABLES -
REFERENCES -
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ROGER CONANT "Observations on Garter Snakes of the Thamnophis eques Complex in the Lakes of Mexico's Transvolcanic Belt, with Descriptions of New Taxa," American Museum Novitates, 2003(3406), 1-64, (22 May 2003)
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