A revision of the South American snake genusThamnodynastes Wagler, 1830

Memoria de la Fundación La Salle de Ciencias Naturales 2007 (“2006”), 166: 7-27

A revision of the South American snake genus Thamnodynastes Wagler, 1830 (Serpentes: Colubridae, Tachymenini). II. Three new species from northern South America, with further descriptions of Thamnodynastes gambotensis Pérez-Santos and Moreno and Thamnodynastes ramonriveroi Manzanilla and Sánchez †Joseph R. Bailey and Robert A. Thomas

Abstract. Three new species of the snake genus Thamnodynastes are described from northern South America: T. ceibae from the Lake Maracaibo Basin of Venezuela, T. dixoni from the Llanos of Colombia and Venezuela, and T. paraguanae from the coastal areas of the Guajira Peninsula of Colombia from the northern Lake Maracaibo Basin and Paraguaná Peninsula of Venezuela. Further descriptions are provided for T. gambotensis and the recently described T. ramonriveroi.

Key words. Serpentes. Colubridae. Xenodontinae. Tachymenini. Thamnodynastes.

Revisión de las serpientes suramericanas del género Thamnodynastes Wagler 1830 (Serpentes: Colubridae, Tachymenini). II. Tres nuevas especies del norte de Suramérica, con descripciones adicionales de Thamnodynastes gambotensis P é rez-Santos y Thamnodynastes ramonriveroi Manzanilla y Sánchez Resumen. Se describen tres especies del género Thamnodynastes del norte de Suramérica: Thamnodynastes ceibae proveniente del sur de la hoya del lago de Maracaibo, T. dixoni de la región llanera de Venezuela y Colombia y T. paraguanae de las áreas costeras de la península de la Guajira en Colombia, norte de la hoya del Lago de Maracaibo y península de Paraguaná en Venezuela. Se presentan descripciones adicionales de Thamnodynastes gambotensis y T. ramonriveroi.

Palabras clave. Serpentes. Colubridae. Xenodontinae. Tachymenini. Thamnodynastes.

Introduction The herpetological literature of northern South America is liberally sprinkled with specimens identified as “T h a m n o d y n a stes sp.” This is due to the fact that Thamnodynastes is among the most misunderstood snake genera in the world, coupled with confusion about the definition of T. strigilis (virtually every Thamnodynastes specimen with keeled dorsal scales is classified as this species). Bailey et al. (2005) resolved the problem by, after examining its syntypes, placing T. strigilis (Thunberg 1787) in the synonomy of T. pallidus (Linnaeus 1758), thus facilitating the assignment of new names and clarifying relationships within the genus.

The following species of Thamnodynastes are components of the Venezuelan and Colombian herpetofaunas: T. chimanta Roze 1958, T. corocoroensis Gorzula and

8

Revision of the South American Thamnodynastes

Ayarzagüena 1995, T. duida Myers and Donnelly 1996, T. marahuaquensis Gorzula and Ayarzagüena 1995, T. pallidus (Linnaeus, 1758) and T. yavi Myers and Donnelly 1996.

Our long-term study of the genus revealed the additional presence of three undescribed species distributed in these two countries, each clearly distinct from one another.

Materials and Methods All scale counts, notations, and terminology used herein follow the standard for snake systematics. We record: numbers of supralabials and note which of those are in contact with the eye; numbers of loreals, pre and postoculars, and temporals (members of this genus most often have primary temporals that touch the rear of the postoculars and secondary temporals that touch the rear of the primaries, and there are often tertiary temporals that touch the secondaries); and infralabials, noting how many touch the primary and secondary genials. Beyond these scale fe a t u re s , Thamnodynastes species have the usual colubrid complement of head scales (one rostral, two internasals, two prefrontals, one frontal, two parietals, two supraoculars, two pairs of nasals, one mental, and two pairs of genials). Any anomalies are mentioned. Ve n t ral scale counts we re taken as suggested by Dowling (1951a); subcaudal counts include the number of double rows as well as the terminal spine.

Scale row reductions are recorded in the manner of Dowling (1951b), with the modifications and summarization model of Thomas (1976).

Measurements of the body were taken in a straight-line with a meter stick: total length is from the tip of the snout to the tip of the tail, tail length from the rear of the cloacal plate to the tip of the terminal spine (for both measurements and counts, specimens lacking an obvious terminal spine were considered to have incomplete tails).

Head measurements were taken with calipers to the nearest millimeter. Head length was measured from the front face of the rostral to the rear margin of the right angle of the jaw; head width was taken at the widest point, and eye length was taken in a straight line from the anterior margin of the eye to the rear margin.

Mention of the projections of the eye are a description of where, on the lateral surface of the head (using named scales as a reference), the measured length of the eye falls when projected forward from the front margin of the eye.

To place size in context, we report the total length size range for the top 25% of specimens. Abbreviations are as follows: Total length TL, snout-vent length SVL, head length HL, head width HW, and subcaudals SC. All tooth counts are of single series and all except the maxillary (most of which were done by cleaning in situ bones) are from prepared skulls. Particular care was taken with the maxillaries to count the smallest anterior tooth (or its socket), which is easily overlooked, thus rendering incorrect counts. When referring to maxillary teeth, “12+2G” means 12 prediastemal teeth followed by two grooved postdiastemal fangs.

The conclusions of this study are based on the examination of specimens borrowed from collections cited in the Acknowledgments section.

Mem. Fund. La Salle de Cienc. Nat. 166

9

Thamnodynastes paraguanae new species Figures 1, 2 and 3 Holotype. MBUCV 1468, from Norte de Paraguaná, Falcón State, Venezuela, collected by a Sr. Toledo, on 21 November 1964.

Etymology. This species is named in allusion to its type locality, the Península de Paraguaná, Falcón State, Venezuela.

Diagnosis. A Thamnodynastes with weakly keeled dorsal scales in 19-19-15 rows; hemipenis very slender without significant spines; maxillary teeth usually 13+2G; infralabials and chin usually heavily pigmented; ventrals and subcaudals generally fewer than neighboring species (see variation below).

Description of holotype. An adult male 477 mm TL, tail 103 mm; tail/TL 21.6%; usual colubrid complement of head scales present; supralabials 8-8, IV&V entering orbit; infralabials 9-9, 5-5 infralabials contacting both genials on each side; loreals single; preoculars single; postoculars 2; temporals 2+3/2+3; ventrals 139; cloacal plate divided; subcaudals 57 and in two rows; dorsal scales keeled with one apical pit; abbreviated dorsal scale row formula 19-19-15, with the following complete formula:

3+4(83)2+3(92) 19(10) ----------17 ---------- 15 (139) 3+4(79)2+3(93) Opisthoglyphous diacranterian (grooved) maxillary teeth 13+2. Slender, head moderately distinct from neck; rostral visible from above; internasals nearly triangular, their common suture about equal to that of the prefrontals which are squarish; frontal slender, longer than its distance from the tip of the snout, equal to the length of the parietals; nasal divided, nostril prominent; eye rather large, its diameter half again its distance from the lip; projected eye length reaches the front of the nostril; supraoculars rather large, at the middle of the eye as wide as the frontal; head length 18.9 mm; head width 10.2 mm.

Color and pattern (in preservative). Above dingy gray with a short nuchal pale stripe from the parietal notch, followed by a series of about 37 median pale spots one scale long before they fade out a few head lengths before the vent; along both sides of the pale-spot row is an inconspicuous row of dark spots about the size of one scale and centering on the 8th scale row; head almost uniformly dark with the eye-angle of jaw and labial markings largely obscured by supplementary pigment; chin dark with contrasting pale centers on the genials and anterior infralabials; throat paler than belly; the characteristic 4-stripe ventral pattern is evident only on the throat; elsewhere supplementary brown suffusion is general. The holotype has several long slits on the belly and the number tag is sewed into the lower jaw.

10

Revision of the South American Thamnodynastes

Variation. There are too few specimens to accurately assess adult size, but the largest male we have is 477 mm TL, and the largest female is 605 mm TL; tail/TL 21.3-24.0% (χ= 22.7±1.2, n= 5) in males, 20.3-23.2% ( χ= 22.1±1.1, n= 7) in females; dorsal scale row formulae 19-19-15(16), scales weakly keeled, with the following summation of scale row reductions (n= 4):

2+3[1]χ= 90.0 3+4[3](84-93) 19(10) ----------------- 17 3+4[3] (84-93) 2+3[1] χ= 89.3

2+3[2]χ= 106.0 3+4[2] (95-113) χ=142.5 ------------------- 15 (136-147) 3+4[1] (98-111) 2+3[1] χ= 106.8

Ventrals 136-152 (χ=146.5±7.3, n= 6) in males, 134-150 ( χ=141.0±5.6, n= 12) in females; cloacal plate divided (17); subcaudals 57-65 (χ= 60.2±3.0, n= 6) in males, 5472 (χ= 60.5±5.0, n= 10) in females; ventrals+subcaudals 193-218(χ= 205.1±10.1, n= 7) in males, 190-211(χ =201.5±6.97, n= 8) in females; supralabials 7(2) or 8(32), supralabials entering orbit 3+4(2) or 4+5(32); infralabials 8(2) or 9(30), with 4(2) or 5(30) touching the genials; preoculars 1(30) or 2(2); postoculars 2(32); temporals 1+1+2(1), 1+2(1), 1+3(1), 2+2(9), or 2+3(14); prediastemal maxillary teeth 12(3), 13(10), or 14(1).

A para-topotype (UMMZ 217112) is almost identical to the holotype except that it has only 136 ventrals, temporals 2+3, and it is the only specimen with two preoculars.

This species overlaps with its geographic neighbors in ventral and subcaudal counts. However, much of the overlap in both counts is due to the inclusion of one female and her progeny (FMNH 5682 [the mother] and FMNH 23780-84, removed from the uterus [one additional embryo was left in place]). Future collections may clarify this situation.

Figure 1.

Thamnodynastes paraguanae holotype (MBUCV 1468). a) dorsal view, b) ventral view.

Mem. Fund. La Salle de Cienc. Nat. 166

11

Figure 2.

Thamnodynastes paraguanae (WWL 3062, from Uribia, Guajira, Colombia). Photo by William W. Lamar.

Figure 3.

Head pattern of Thamnodynastes paraguanae (WWL 3062, from Uribia, Guajira, Colombia). Photo by William W. Lamar.

12

Revision of the South American Thamnodynastes

Distribution. All available specimens of Thamnodynastes paraguanae have come from coastal or near coastal localities on the Guajira Peninsula of Colombia, the northern portion of the Lake Maracaibo Basin and east to the Paraguaná Peninsula in Falcón, Venezuela (Figure 4). According to Hueck and Seibert (1972), the vegetation of the area is thorn or cactus shrub. The annual precipitation at Maracaibo city is less than 800 mm, almost all of which comes during the high-sun period of March through October (Atlas Agrícola de Venezuela 1960). This species inhabits a semidesert region experiencing the lowest rainfall and the highest mean annual temperature (over 28 °C) encountered by any member of the genus. The only other known Thamnodynastes from the Maracaibo Basin is T. ceibae (described below) from coastal Trujillo, a much more humid area at the southeastern corner of the lake.

Natural history and ecology. A specimen from Campo Mara collected in July 1964 contained a Cnemidophorus in its gut.

Identification corrections. Specimens of this species that have been erroneously refe rred to in the lite ra t u re include: Müller (1895: 206; four specimens fro m “Maracaybo” listed as T. nattereri), Brongersma (1940: 128-130; RMNH 7847 from Río Hacha, Goajira Peninsula, Colombia, as Dryophylax strigilis), and Viloria and Calchi La C. (1993:44). Campbell and Lamar (1989: Fig. 561) show a color photo of WWL 3062 from Uribia, La Guajira, Colombia, as Thamnodynastes sp.; Campbell and Lamar (2004, Pl. 1320) say of WWL 3062, “This may represent a population of T. gambotensis.”

Figure 4.

Distributions of Thamnodynastes paraguanae (solid circles), T. dixoni (solid triangles), T. ceibae (open square), T. gambotensis (open triangles), and T. ramonriveroi (solid squares).

Mem. Fund. La Salle de Cienc. Nat. 166

13

Thamnodynastes dixoni, new species Figures 5, 6 and 7 Holotype. TCWC 44896, collected 17 October 1973, by James R. Dixon and Mark A. Staton at Hato La Guanota, 4 km west of San Fernando, Apure State, Venezuela.

Etymology. This species is named after our friend and mentor (for RAT), James R. Dixon, who has published prolifically on the herpetofauna of South America. He spent many years researching a variety of species in the llanos of Venezuela.

Diagnosis. A Thamnodynastes of typical pattern with smooth or weakly keeled scales in 19-19-15 rows; cloacal plate divided; chin with distinct but not strong chin stripes (as the dark markings characteristic of T. paraguanae); ventrals in males 152-160, females 141-150; maxillary teeth 12-15+2G (about 70% have 13-14+2G). A very slender spineless hemipenis.

Description of holotype. An adult female 432 mm TL, tail 95 mm; tail/TL 21.99%; usual colubrid complement of head scales present; supralabials 7-8, III&IV/IV&V entering the orbit; infralabials 9-9; 5-5 infralabials contacting both genials on each side; loreals single; preoculars single; postoculars 2; temporals 2+3/2+3; ventrals 150; cloacal plate divided; subcaudals 64 and in two rows; dorsal scales weakly keeled above the third row; abbreviated dorsal scale row formula 19-19-15, with the following complete formula:

2+3(94) 2+3(103) 19(10) ------------ 17 ------------15 (150) 3+4(94) 2+3(104) O p i sth o glyphous diacranterian maxillary te eth 13+2. Head dark ly stippled dorsally, laterally with a narrow stripe from eye to angle of jaw and a conspicuous teardrop mark from center of eye posteriorly onto the subocular supralabial (Figure 6); chin with infralabials bearing stippling along their genial margins, especially on the fifth infralabial; scattered stippling along the median genial suture (Figure 7); venter generally pale with outer stripes present but not strongly developed, except for a pair of dots on the anterior margin of each ventral; inner stripes very weakly developed and chiefly represented by a lesser row of dots per scale; a few stipplings scattered elsewhere; the outer stripes continuing onto the subcaudals; SVL 334mm, tail 96mm; tail/SVL ratio 28.7%; head length 17.7mm, head width 9.0 mm; rostral visible from above; internasal suture about equal to that between prefrontals; frontal narrow, considerably longer than its distance from the tip of the snout, about equal to the length of the parietals; eye moderate, its diameter greater than its distance from the lip, projected it reaches the center of the nostril; pupil oval.

14

Revision of the South American Thamnodynastes

Variation. Adult size range (based on our largest 25% of specimens) is 495-518 mm total length in males, and 388-484 mm in females; tail/TL 20.2-24.0% (χ=22.4±1.3, n= 14) in males, 20.7-23.1% (χ=22.2±0.75, n= 13) in females; dorsal scale row formulae 1919-15(26), scales weakly but obviously keeled above the third DSR, and with the following summary of scale row reductions (n= 5): 4+5[1] 4+5[1] 3+4[3] χ= (107.2) 3+4[2] χ= 114.2 2+3[1] (96-115) 2+3[2] 99-131 χ= 146.8 19 ---------------------- 17 --------------------- 15 (141-155) 3+4[3] (93-115) 2+3[2] (102-129) χ= 105.4 3+4[2] χ= 114.8 4+5[1]

Ventrals 152-160 (χ =153.5±4.4, n= 15) in males, 141-150 (χ =146.2±3.2, n= 11) in females; cloacal plate divided (26) or single (1); subcaudals 63-72 (χ=66.9±3.2, n= 13) in males, 57-66 (χ=62.0±3.0, n= 10) in females; supralabials 7(15) or 8(39), supralabials entering orbit III+IV(15), III-V(1), or IV+V(38); infralabials 8(1) or 9(40), with 4(1) or 5(49) touching the genials; loreals 1(32) or 2(2); preoculars 1(53) or 2(1); postoculars 2(54); temporals 1+1+3(5), 1+3(2), 2+2(7), 2+2+3(6), or 2+3(31); prediastemal maxillary teeth 12(4), 13(10), 14(7), or 15(4). The cleaned skull of TCWC 46272 has the following tooth numbers: maxillary 14+2G/14+2G (included in above counts), dentary 19/17, palatine 11/9, and pterygoid 21/20.

One neonate had 120 ventral scales anterior to the umbilicus, and 4 ventrals in the umbilical scar.

The projected eye diameter varies from the back of the nostril to the edge of the rostral; single scale pits may be seen in well preserved material.

The hemipenis is partially everted in several specimens; all organs are slender, shallowly bifurcate and spineless. MBUCV 8153 has the organ everted, five subcaudals long and divided at its distal end; the sulcal lips are prominent. The sulcus enters the valley between the lobes, one lip extending into each lobe with the sulcus forming a clear triangle between; tiny spinules adorn the outer two-thirds of the organ except on the sulcal lips.

The chin pigmentation of T. dixoni is somewhat variable. In four specimens it is lacking, in 12 it is pale or weakly developed, and in six there are normal chin stripes.

In none does the chin show the contrasting black and white characteristic of T. paraguanae. Rather, it is stippled giving a pale gray appearance.

Distribution. This species is essentially a resident of the vast llanos of southwestern Venezuela and southeastern Colombia, the extensive seasonal marshes in the Orinoco River Basin (Figure 4). It is a species of low elevations, probably seldom if ever exceeding 500 m. It is not known to co-exist with T. ramonriveroi to the north and east at either high or low elevations in eastern Venezuela and the Guianas. The distribution

Mem. Fund. La Salle de Cienc. Nat. 166

15

Figure 5.

Thamnodynastes dixoni holotype (TCWC 44896). a) dorsal view; b) ventral view. Photo

by R. Katheryn Vaughn.

Figure 6.

Lateral head pattern of the holotype of Thamnodynastes dixoni (TCWC 44896). Photo

by Mickey Bailey.

Figure 7.

Chin and neck pattern of the holotype of Thamnodynastes dixoni (TCWC 44896).

Photo by Mickey Bailey.

16

Revision of the South American Thamnodynastes

to the south is entirely conjectural. A little southeast of El Manteco and the impoundment at El Guri mark the eastern limits of the known range. Clearly much remains to be done to clarify this species’ range limits.

Identification corrections. This species has been referred to as T. strigilis by Roze (1966), Staton and Dixon (1977), and Rivero-Blanco and Dixon (1979: 298, in part, from llanos and Yuruari Savanna).

Thamnodynastes ceibae new species Figure 8 Holotype. UMMZ 218579 (formerly MBUCV 8165), from La Ceiba, Trujillo State, Venezuela, collected by Janis Racenis and Janis A. Roze, 19 May 1963, near sea level.

No other specimens are known.

Etymology. This species is named for its type locality, La Ceiba, Trujillo State, Venezuela.

Diagnosis. A slender Thamnodynastes of ordinary pattern with weakly keeled dorsals in 19-19-13 rows; cloacal plate divided; hemipenis short, very slender without perceptible ornamentation; maxillary teeth 19+2G. Description of holotype. An adult male 583 mm TL, tail 135 mm; tail/TL 23.2%; usual colubrid complement of head scales present; supralabials 8-8, IV+V entering orbit; infralabials 9-9; 5-5 infralabials contacting both genials on each side; loreals single; preoculars single; postoculars 2-3; temporals 2+3/2+3; ventrals 150; clocal plate divided; subcaudals 67, in two rows; dorsal scales weakly keeled with one apical pit; abbreviated dorsal scale row formula 19-19-13, with the following complete formula:

3+4(95) 2+3(108) 2+3(133) 19(10) ------------ 17 ------------ 15 ------------ 13 (150) 3+4(97) 2+3(107) 2+3(138) It is unusual to have three reductions in Thamnodynastes, and this condition in the holotype could be an anomaly.

Opisthoglyphous diacranterian maxillary teeth 19+2. Eye large, its diameter equal to half the distance between nostril and rostral, the lip below orbit equal to about half the eye diameter; nasal partially divided; nuchal stripe present; almost no dark dorsal spots evident unless the skin is stretched, but there is a series of pale median spots an a lateral dark-stripe beginning at about the anterior fifth of the body length; chin pale with a few dark spots representing chin stripes; venter with and outer pair of dark lines and two inner series of streaks plus scattered dots posteriorly; the hemipenis is very slender, about 1.5 mm in diameter and 8 mm (6 subcaudals) long to retractor muscle;

Mem. Fund. La Salle de Cienc. Nat. 166

17

both sulcus and hemipenis divide at 7 mm where the sulcus opens onto the inner surface of the fork which bears no ornamentation; sulcal lips very prominent throughout and many tiny spinules adorn the central portion of the shaft, but they are only a fraction of the height of the sulcal lips at 30x magnification; basally there are some short, blunt tubercles.

Figure 8.

Thamnodynastes ceibae holotype (UMMZ 218579). a) dorsal view, b) ventral view. Photo

by Greg Schneider.

Distribution. This is the only species of Thamnodynastes known from the southern portion of the Lake Maracaibo Basin (Figure 4), which is significantly more humid than more northern localities where T. paraguanae is found.

Hueck and Seibert (1972) described the area surrounding La Ceiba as deciduous mesosphytic tropical forest with a strong component of evergreen species. The mean temperature for the period 1951-1955 were in the range of 24-28 °C (Atlas Agrícola de Venezuela, Map 8, 1960).

Comments and relationships. The relationships of this form are enigmatic. The slender spineless hemipenis allies it with T. paraguanae and T. dixoni, which are geographic neighbors, but it differs from these and all other species except the pallidus group in dorsal scale row reduction to 13 rows before the vent (but differs from the T. pallidus group in lateral rows 3&4 being involved in both reductions vs. 3&4 then 6&7 or 7&8 in T. pallidus). The high maxillary number (19+2G) also suggests the T. pallidus group, but the keeled condition of the scales and presence of a scale pit contraindicate such an affinity; this is the only character that separates this species from T. paraguanae and T. dixoni.

18

Revision of the South American Thamnodynastes

Thamnodynastes gambotensis Pérez-Santos and Moreno Thamnodynastes gambotensis Pérez-Santos and Moreno, 1989a:1-9 (also illustrated in their 1989b paper).

Etymology. The species is named for its type locality: Gambote, Bolívar Department, Colombia.

Diagnosis. A Thamnodynastes with 19 dorsal rows, smooth or weakly keeled; a single scale pit; hemipenis stout and spinous; maxillary teeth 12-14+2G with a mode of 13+2G (76%); chin heavily pigmented, but the larger scales may have contrasting pale centers; frequently seven supralabials (60%).

Description and variation. The description of this species requires amplification.

Adult size range (based on our largest 25% of specimens) is 493-514 mm total length in males, and 404-457 mm in females; tail/TL 18.5-23.4% (χ= 21.6±1.95, n= 14) in males, 18.1-23.8% (χ= 21.1±1.95, n= 14) in females; dorsal scale row formulae 19-19-15(16), scales smooth or weakly keeled, with the following summary of scale row reductions:

χ= 103.1 3+4[7] χ= 118.6 3+4[8](89-118) 2+3[1] (106-132) χ= 154.0 19(10) --------------------- 17 ------------------- 15 (146-161) 3+4[7] (91-118) 2+3[2] (111-131) 4+5[1] χ= 102.6 3+4[6] χ= 117.5 Ventrals 150-164 (χ=157.4±3.9, n= 19) in males, 145-155 (χ= 149.1±2.8, n= 24) in females; cloacal plate divided (22); subcaudals 63-73 (χ=69.0±2.9, n=14) in males, 5372 (χ= 61.6±2.8, n= 24) in females; ventrals+subcaudals 213-235 (χ= 225.6±6.2, n= 14) in males, 201-223 (χ= 210.3±5.5, n= 24) in females; supralabials 7(33) or 8(23), supralabials entering orbit III+IV(33) or IV+V(23); infralabials 8(2) or 9(53), with 4(2), 5(53), or 6(1) touching the genials; loreals 1(56); preoculars 1(54) or 2(2); postoculars 2(56); temporals 1+1+2(1), 1+1+3(2), 1+2(5), 1+2+3(3), 1+3(8), 2+2(23), 2+2+3(12), 2+2+4(1), or 2+3(12); prediastemal maxillary teeth 12(2), 13(19), or 14(4).

This is the only one of a group of geographically neighboring species to have a stout, spinous hemipenis. The high percentage of seven supralabials (ca. 60%) is notable but not diagnostic. Like its geographic neighbors, this species has the dorsal scales smooth (78%) or weakly keeled (22%). The chin and infralabials are usually rather strongly marked as well illustrated in the original description (Pérez-Santos and Moreno 1989a, Figures 1 and 2) and the color photo (ibid, Figure 4).

Distribution. The distribution of Thamnodynastes gambotensis as understood at present is restricted to the lower río Magdalena Basin and the adjacent Caribbean lowlands (Figure 4). However, the known existence of a form with a stout, spinous hemipenes in eastern Colombia east of the Andes leaves the question open to further investigation.

Mem. Fund. La Salle de Cienc. Nat. 166

19

Identificaction corrections. As noted above, the specimen Campbell and Lamar (2004, Pl. 1320) said may be a population of Thamnodynastes gambotensis is actually a specimen of T. paraguanae.

Thamnodynastes ramonriveroi Manzanilla and Sánchez, 2005 Figures 9 and 10 Diagnosis. A northern dwarfed relative of Thamnodynastes strigatus, from which it differs chiefly in its smaller size, lesser development of para-cloacal tubercles in males, a higher modal maxillary tooth count, and in possessing enlarged basal hooks on the hemipenis.

Description of a typical specimen. An adult male (CM 7981), collected by M.G. Netting on January 14, 1930, at Elvécia, Sucre State, Venezuela.

A medium-sized, rather stocky snake with smooth dorsal scales in the formula 1919-15, reducing twice by the loss of the fourth lateral row opposite ventrals 69 and 84, respectively; a single scale pit is distinct on most of the scales that have not slipped; ventrals 147; cloacal plate divided; subcaudals 62 plus a terminal spine; supralabials 88, third (very narrowly) to fifth entering the orbit; infralabials 9-9, the anterior five in contact with the genials; one pre and two postoculars on each side; nasal divided below nostril; loreal with its lower margin nearly twice as long as the upper; two temporals contact the postoculars; paracloacal tubercles scarcely evident; TL 492mm; tail 112mm; tail/SVL ratio 22.8%; HL 18.5mm; orbit 3.3mm, projecting to front of nostril; maxillary te eth 16+2G. Nu chal pale st ripe about 13 scales long befo re being interrupted into a series of mid-dorsal pale spots about the size of the eye; ground color slate gray where scales have slipped and brown where they are present; scales between and on either side of pale dorsal spots are edged with black on the anterior part of the body becoming inconspicuous posteriorly; a dark lateral stripe follows t he fourth lateral row; the top of the head is gray with darker mottlings; the eye to angle of jaw stripe is well developed, meeting the orbit on the postocular suture and continuing anteriorly from orbit to nostril; five pale centered dark spots on the supralabials, the largest on the fifth, plus a few irregular smaller markings; chin bars and scattered dark spots present on the throat; five rows of dark spots with paler centers on the ventrals with additional pigment between the rows, the outermost pair of which are much the darkest and separated from the dorsal color by a narrow pale line, which is not sharply demarcated.

CM 7981 is described in Netting’s field notes as follows: “greenish above with dark blackish spots and light greenish between markings below, iris light brown.”

Hemipenis: right organ dissected; organ stout, nine SC long to retractor muscle, very shallowly bilobed; sulcus divided opposite seventh SC; five enlarged basal hooks inserted opposite fourth SC, the largest para-sulcal, with the anti-sulcal somewhat smaller, all followed by about 22 transverse rows of spines of decreasing size merging into calcyes at about the level of the sulcal fork.

20

Revision of the South American Thamnodynastes

Variation. Adult size range (based on our largest 25% of specimens) is 420-481 mm total length in males, and 345-379 mm in females; tail/TL 20.1-25.8% (χ= 23.5±1.5, n= 16) in males, 22.0-24.8% (χ= 22.6±1.1, n= 7) in females; dorsal scale row formulae 1719-15(1), 19-19-15(35), or 19-19-13(1), scales smooth, with the following summary of scale row reductions (n= 9):

χ= 84.1 3+4[5] χ= 99.1 3+4[9](69-108) 2+3[4] (84-121) χ= 144.4 19(10) ------------------ 17 ------------------ 15 (137-149) 3+4[9] (71-106) 2+3[4] (84-122) χ= 84.3 4+5[5] χ= 98.9 Ventrals 143-155 (χ= 147.5±2.5, n= 25) in males, 137-142 (χ= 139.4±1.7, n= 14) in females; cloacal plate divided (34) or single (6); subcaudals 58-79 (χ=66.4±4.9, n= 23) in males, 54-66 (χ= 60.1±3.2, n= 14) in females; supralabials 8(78) or 9(2), supralabials entering orbit III-V(8), IV+V(70), or V+VI(2); infralabials 6(1), 8(16), 9(59), or 10(4), with 4(1), 5(75), or 6(4) touching the genials; preoculars 1(79) or 2(1); postoculars 2(80); prediastemal maxillary teeth 15(1), 16(11), 17(17), 18(3), or 19(1). Two skulls had the following tooth counts: MVZ 172400 - maxillary teeth 16+2/16+2 (included in previous counts), dentary teeth 21/21, right palatine 14, right pterygoid 18; MVZ 172401 - right maxillary teeth 17+2 (included in previous counts), right dentary 22, palatines 18/18.

Our material separates into two phenotypic and geographic groups, an upland group from Mt. Turumiquire with which the single Brazilian specimen from alto rio Catrimany seems to align, and a lowland group, comprising the sample from Trinidad, the Orinoco Delta, and the coastal Guianas. The ventral statistics of the two lots are presented in table 1. The lowland group is also paler in coloration, especially ventrally.

At this time, we ascribe no taxonomic significance to these observations.

The relative incidence of undivided cloacal plates is particularly high in males from Suriname, which have the undivided and divided conditions about equal. A lowland female from “Guiana” has the last ventral fused to the right half of a undivided cloacal plate. In all other specimens, the cloacal plate is divided.

There is a tendency in the lowland population for the second dorsal reduction to involve a higher dorsal scale row than usual, thus: third (3 times), fourth (10), fifth (9), sixth (2), seventh (1), and eighth (1) as in the pallidus group. In the upland sample comparable data are: third (3), fourth (8). The first reduction is almost always (90%) by loss of the fourth row, with the remaining 10% the third row.

Because fresh coloration is rarely documented and because there appears to be significant variation in details, we offer Netting’s descriptions of specimens in the Elvécia series: CM 7976, male- “olive brown above with two rows small black marks, brown lateral stripes, sides olive green, light greenish below with gray markings, iris red brown.” CM 7977, female- “dark gray brown above with two rows of small black marks, black lateral stripes, sides blackish, white below with many gray markings

Mem. Fund. La Salle de Cienc. Nat. 166

21

which become black posteriorly, iris dark brown.” CM 7979, female- “dark brown above.” CM 7980, male- “brown above, lt. orange between belly and tail markings, iris orange.” CM 7984, male- “brown above with black marks, olive brown laterally, very light pink between belly markings.” CM 7998, male- “brown above.” CM 7999, male“brown above with row of light spots along mid-dorsal line, cream between markings below with light orange cast.” CM 8000, male- “head light ochre brown, iris light red brown, light reddish brown above with black mottlings, cream below with light brown marks.”

Several specimens preserved with hemipenis extruded are similar to the dissected organ of CM 7981 described above.

Table 1.

Variation in ventral and subcaudal numbers in lowland and highland populations of Thamnodynastes ramonriveroi in northern Venezuela.

No. Lowland Highland

17 10

Lowland Highland

16 8

Males Range Mean SD Ventrals 144-153 148.0 2.3 139-149 145.4 2.9 Subcaudals 62-72 67.6 2.7 58-64 62.4 2.7

Females No. Range Mean

SD

14 2

137-145 137-138

140.5 137.5

2.4 -

14 2

57-63 54-55

60.9 54.5

2.2 -

D i st ribution. The dist ribution of T h a m n o d y n a stes ra m o n ri ve roi ( Fi g u re 4) is interesting and has some curious parallels with its southern relative T. strigatus. The elevational distribution is considerable, from near sea level in the lowland populations to at least over 1750 m on Mt. Turumiquire on the Sucre-Monagas-Anzoategui border in Venezuela. The upland and coastal populations differ somewhat as elaborated

Figure 9.

Thamnodynastes ramonriveroi (MBUCV 399). a) dorsal view, b) ventral view.

22

Revision of the South American Thamnodynastes

above, but we do not imply that they are genetically separated from each other. Much more field and genetic data would be needed to prove or disprove such a suggestion.

The only Brazilian specimen, from the alto rio Catrimany (MNRJ 668), rio Branco, was long believed to be the only apparent specimen of Thamnodynastes strigatus from the north, some 3000 km from the nearest conspecific; but there was no other reason to question its provenance. In fact, Franco and Ferreira (2003) recently cited this specimen and another as evidence for a northern population of T. strigatus.

With the discovery of T. ramonriveroi as a valid species, the identity of MNRJ 668 is solved, as it compares perfectly with the type series; however, it’s locality lies some 930 km south of Mt. Turumiquire and 650 km from the closest Guiana records.

Boos (1984) reported the first known specimen from Trinidad (there are now three existing from that island – see Murphy 1997, Boos 2001); he called it Thamnodynastes strigatus.

The only congener sympatric with Thamnodynastes ramonriveroi is T. pallidus, both of which are recorded from Nieuw Nickerie and Paramaribo, Suriname, and from Demerara (Georgetown), Guayana.

All localities are in areas of original forest.

Natural history and ecology. There is considerable evidence that the species is at least semi-aquatic. An Elvécia specimen was noted by Netting: “Caught crawling in a small pool. Swam easily and well. Flattened the entire first half of body and when tormented opened mouth very widely; played possum when struck with a light stick” (the flattening behavior is shown in Manzanilla and Sánchez 2005, Figure 3b). His

Figure 10. Thamnodynastes ramonriveroi from Icacos, Trinidad. Photo by Hans Boos.

Mem. Fund. La Salle de Cienc. Nat. 166

23

field notes for another specimen give the local name as “mapanare del agua”. A preserved specimen from “Guyana” had a small cyprinodontid fish in its mouth, and one from Suriname had eaten a metamorphosing tadpole.

Three gravid females have been examined: CM 7977, 337mm SVL, with five embryos, was taken January 13, 1930; RMNH 990, 365mm SVL, contained four embryos; and in AMNH 36119, 348mm SVL, two eggs were observed.

Comments and relationships. Without question, Thamnodynastes ramonriveroi is closely related to T. strigatus of southern Brazil, Uruguay and Argentina. Aside from size differential, T. ramonriveroi differs in having small broods, slightly high ventral and subcaudal numbers, a higher modal maxillary count, and in having the basalmost spines on the hemipenis noticeably enlarged. Both species share dark, wide outer pair of ventral stripes and prominant labial markings. Some of the largest male T. ramonriveroi have paracloacal tubercles, but they are less evident than those of T. strigatus. This character is, however, a function of size within the species as well as between species.

Identification corrections. Based on specimens examined by us, the following authors have treated Thamnodynastes ramonriveroi specimens using other names: Günther (1858:164), T. nattereri from Demerara; Boulenger (1896:117, specimens Cac), same specimens (BMNH 1967.2201-03); Hoogmoed (1979:253,276), T. strigilis; and Cadle (1984:14), MVZ 172401 (T. sp). Murphy (1997:197-99) described specimens from Trinidad of this species as Thamnodynastes sp. Also, see the comments under “Distribution” above.

The authors have for years had specimens of this species labeled as Thamnodynastes nettingi (our name for the species; now a nomen nudum).

Acknowledgments. James R. Dixon’s collections of Thamnodynastes (now in TCWC) from the llanos of Venezuela, as well as conversations with Carlos Rivero-Blanco and Mark A. Staton, stimulated the junior author to work on the genus. We thank the following curators and collections managers for many courtesies: George Foley, Linda Ford, Charles W. Myers, and Richard G. Zweifel, American Museum of Natural History (AMNH); C. J. McCarthy and Andrew F. Stimson, Natural History Museum of London (BMNH); the late C. J. McCoy, the late M. Graham Netting, and Ellen J. Censky, Carnegie Museum of Natural History (CM); Robert F. Inger, Hymen Marx, Alan Reseter, and Harold K. Voris, Field Museum of Natural History, Chicago (FMNH); the late Alphose R. Hoge and S. Alma R. W. L. Romano, Instituto Butantan (IBSP); the Instituto Ciencias Naturales, Universidad Nacional Colombia, Bogotá (ICNMNH); Robert Bezy and John W. Wright, Natural History Museum, Los Angeles County (LACM); Janis Roze and Janis Racenis, Museo de Biologia, Universidad Central de Venezuela, Caracas (MBUCV); Abdem R. Lancini, Museo de Ciencias Naturales, Caracas (MCNC); John E. Cadle, Patricia G. Haneline, José Rosado and Ernest E. Williams, Museum of Comparative

24

Revision of the South American Thamnodynastes

Zoology, Harvard University (MCZ); the late Antenor Leitao de Carvalho, Museo Nacional, Rio de Janeiro (MNRJ); Harry W. Greene and David B. Wake, Museum of Vertebrate Zoology, University of California-Berkeley (MVZ); Marinus S. Hoogmoed, Rijksmuseum van Natuurlijke Historie, Leiden (RMNH); the late Hermano Nicéforo María, Museo de Historia Natural La Salle, Bogotá (SCN); James R. Dixon and R. Kathryn Vaughan, Texas Cooperative Wildlife Collection, Texas A&M University, College Station (TCWC); Arnold G. Kluge, Ronald Nussbaum, and Greg Schneider, Museum of Zoology, University of Michigan (UMMZ); the late Doris M. Cochran, Steve Gotte, W. Ronald Heyer, Frances I. McCullom, the late James A. Pete rs, Robert P. Reynolds, and George Zug, National Museum of Natural Histo ry, Smithsonian Institution (USNM); Jonathan A. Campbell, University of Texas at Arlington (UTA); William W. Lamar, personal collection (WWL); and Wolfgang Böhme and Paul M. Kornacker, Zoologisches Forschungsinstitut und Museum Alexander Koenig, Bonn (ZFMK).

We also thank those photographers noted in the figure captions. Krista Whittington produced the final versions of the maps, and Lisa M. Boe and Adriana Valdez Avakian helped with translations.

Bibliography.

BAILEY, J. R., R. A. THOMAS AND N. J. DA SILVA. 2005. A revision of the South American snake genus Thamnodynastes Wagler, 1830 (Serpentes: Colubridae, Tachymenini). I. Two new species of Thamnodynastes from central Brazil and adjacent areas, with a redescription of and neotype designation for Thamnodynastes pallidus (Linnaeus, 1758). Phyllomedusa 4: 83101.

BOOS, H. 1984. A new snake for Trinidad. Living World, Journal of the Trinidad-Tobago Field Naturalist’s Club 3(1983/84): 2.

BOOS, H. 2001. The snakes of Trinidad & Tobago. Texas A&M Univ. Press, College Station.

BOULENGER, G. A. 1896. Catalogue of the snakes in the British Museum (Natural History). Vol. 3, British Museum (Natural History), London.

BRONGERSMA, L. D. 1940. Snakes from the Leeward Group, Venezuela and Eastern Colombia.

Studies on the fauna of Curação, Aruba, Bonaire, and the Venezuelan Islands. 2(8): 116-137.

CADLE, J. E. 1984. Molecular systematics of neotropical xenodontine snakes. I. South American xenodontines. Herpetologica 40(1): 8-20.

CAMPBELL, J. A. AND W. W. L AMAR. 1989. The venomous reptiles of Latin America. Cornell University Press, Ithaca, NY. CAMPBELL, J. A. AND W. W. L AMAR. 2004. The Venomous Reptiles of the Western Hemisphere.

Vol. II. Comstock Publishing Company, Ithaca, NY. DOWLING, H. G. 1951a. A proposed standard system of counting ventrals in snakes. British Journal Herpetology 1: 97-99.

DOWLING, H. G. 1951b. A proposed method of expressing scale reductions in snakes. Copeia 1951: 131-134.

FRANCO, F. L. AND T. G. FERREIRA. 2003. Ocorrência de Thamnodynastes strigatus (Serpentes, Colubridae) no Escudo das Guianas, estados do Pará e Roraima, Brasil. Phyllomedusa 2(2): 117-19.

G ORZULA , S. AND J. AYA R Z AG Ü E NA. 1995(1996). Dos nuevas especies del gé n e ro Thamnodynastes (Serp e n tes: Colubridae) de los tepuyes de la Guayana Venezolana.

Publicaciones de la Asociación Amigos Doñana 6: 1-17.

GÜNTHER, A. 1858. Catalogue of the colubrine snakes in the collection of the British Museum.

London. 281 pp.

Mem. Fund. La Salle de Cienc. Nat. 166

25

HOOGMOED, M. S. 1979. The herpetofauna of the Guianan region. Pp. 241-280. In: Duellman, W. E. (Ed.). The South American herpetofauna: its origin, evolution, and dispersal. Museum of Natural History, University of Kansas, Monogr. 7.

HUECK, K. AND P. SEIBERT. 1972. Mapa de la vegetación de America del Sur. Erlauterungen 1:8 millionen. G. Fisher. Stuttgart.

LINNAEUS, C. 1758. Systema Naturæ per Regna Tria. X. Vol 1, Pt. 1. Laurentii Salvii Holmiæ.

MANZANILLA , J. AND D. SÁNCHEZ. 2005 (2004). Una nueva especie de Thamnodynastes (Serpentes: Colubridae) del Macizo del Turimiquire, noreste de Venezuela. Memoria de la Fundación La Salle de Ciencias Naturales 161-162: 61-75.

MÜLLER, F. 1895. Siebenter Nachtrag zum Katalog der herpetologischen Sammlung des Basler Museums. Verhandlungen Naturforschende. Gesellschaft Basel 10: 195-215.

MURPHY, J. C. 1997. Amphibians and reptiles of Trinidad and Tobago. Krieger Publishing Company. Malabar, Florida, USA. MYERS, C. W. AND M. A. DONNELLY. 1996. A new herpetofauna from Cerro Yaví, Venezuela: First results of the Robert G. Goelet American Museum-Terramar Expedition to the northwestern Tepuis. American Museum Novitates (3172):1-56.

PÉREZ-SANTOS, C. E. AND A. G. MORENO. 1989a. Una nueva especie de Thamnodynastes (Serpentes: Colubridae) en el norte de Colombia. Bolletino del Museo Regionale di Scienze Naturali, Torino 7(1): 1-9.

PÉREZ-SANTOS, C. E. AND A. G. M ORENO. 1989b. Addenda y corrigenda al libro “Ofidios de Colombia.” Bolletino del Museo Regionale di Scienze Naturali, Torino 7(1): 1-17.

RIVERO-BLANCO, C. AND J. R. DIXON. 1979. Origin and distribution of the herpetofauna of the dry lowland regions of northern South America. Pp. 281-298. In: Duellman, W. E. (Ed.), The South American herpetofauna: its origin, evolution, and dispersal. Museum of Natural History, University of Kansas, Monograph 7.

ROZE, J. A. 1958. Los reptiles del Chiminantá tepui (Estado Bolívar) Venezuela, colectados por la expedición botánica del Chicago Natural History Museum. Acta Biologica Venezuelica 2(25): 299-314.

ROZE, J. A. 1966. La taxonomía y zoogeografía de los of idios en Venezuela. Ediciones de la Biblioteca UCV, Caracas. 362 pp.

STATON, M. A. AND J. R. DIXON. 1977. The herpetofauna of the central llanos of Venezuela: noteworthy records, a tentative checklist and ecological notes. Journal of Herpetology 11:1724.

THOMAS, R. A. 1976. Comments on the use of dorsal scale row formulae in snakes. Copeia 1976: 839-841.

VILORIA, A. L. AND R. CALCHI L A. C. 1993. Una lista de los vertebrados vivientes de la sierra de Perija, Colombia y Venezuela. Biollania 9: 37-98.

26

Revision of the South American Thamnodynastes

Specimens Examined Thamnodynastes ceibae.VENEZUELA. Trujillo: La Ceiba (UMMZ 218579).

Thamnodynastes dixoni. COLOMBIA. Arauca: Cravo Norte (AMNH 97474).VENEZUELA. Amazonas: Puerto Ayacucho (FMNH 178697, USNM 80684, 22685). Apure: 5.0 km SW Bruzal (TCWC 46274); Hato La Guanota, 4 km W San Fernando de Apure (TCWC 44895896); 6.0 km W San Fernando de Apure, 100 m (TCWC 46270-272); río Cinaruco, 41 km NW Puerto Páez (USNM 162815). Bolívar: Represa El Guri (MBUCV 841-42, 844, 847); 16 km SE El Manteco, 320 m (TCWC 59034). Guárico: Calabozo, represa de Guárico (MBUCV 8153); Espino (MCNC 117); 33.6 km N Corozo Pando (TCWC 47329); ca. 15.0 km N Corozo Pando, Rt. 2 (TCWC 47939); 9.6 km N Corozo Pando, Rt. 2 (TCWC 47937); 8.0 km N Corozo Pando (TCWC 47330-31); 5.0 km N Corozo Pando, Rt. 2 (TCWC 47940); 8.7 km S Corozo Pando (TCWC 46273); 8.7 km N San Fernando de Apure, Rt. 2 (TCWC 47938); El Sombrero (ZFMK 64422).

Thamnodynastes gambotensis. COLOMBIA. No locality: (USNM 14715, 14717). Atlántico: Barranquilla (SCN 727-28, 731, 733; UMMZ 78276); río Guaimaral (USNM 117502-503); Palmar de Varda (ICNMNH 117). Bolívar: Cartagena (SCN 732, IBSP 10302); region of Santa Rosa near Canal del Dique, 12-20 m (MCZ 175758-765). Cesar: 15 km S Bosconia, Finca El Diamonte (LACM 114651). Córdoba: Monteria (SCN 1944, USNM 163482).

Magdalena: río Frio (MCZ 32752); Cienaga (USNM 144175). Sucre: Sincelejo (ICNMNH 442).

Thamnodynastes paraguanae. COLOMBIA. Guajira: río Hacha (RMNH 7847); 0.5 milepost S Pájaro (USNM 151743-44); Uribia (WWL 3062). VENEZUELA. Falcón: Norte de Paraguaná (MBUCV 1468, UMMZ 217112); Capturida (USNM 217238). Zulia: Lake Maracaibo (FMNH 5682, 23780-84); Maracaibo (USNM 56285); La Macura, Urdaneta, about 50 km WSW Maracaibo city (MBUCV 8152); Campo Mara, Maracaibo (MBUCV no number).

Thamnodynastes ramonriveroi. No data. MVZ 172400. BRAZIL. Roraima(?): rio Branco, alto rio Catrimany (MNRJ 668). GUYANA. No locality: (AMNH 36117-20); Demerara (BMNH 19 67. 2 2 01-03). SURINAM: No locality: (RMNH 990, 13593, 20970).

Commowijne: Plantage Marienberg (RMNH 20961). Coronie: East-west road, km 93 (RMNH 20969). Morowijne: Wia Wia (RMNH 13591); Galibi Station (MVZ 172401).

Nickerie: 10km S Nieuw Nickerie (RMNH 20965-66); East-west road, km 177 (RMNH 20971); East-west road, km 182, just N Wageningen (RMNH 20973). Para: road from Sanderij to Overtoom, 33km S Pa ramaribo (RMNH 20967); road Overtoom to Paramaribo, Sanderij (RMNH 20968); road Meursweg to Parbo-Sanderij (RMNH 20972); Paramaribo-Sanderij, 28 km S Parmaribo (RMNH 15101); 26 km S Mokko-Mokko swamp (RMNH 20960); Onverwacht (RMNH 13592a,b). TRINIDAD. Between Chatham and Cedros, S.W. Trinidad (BMNH 1980.1167); W milepost 70 on S Bonasse-Cedros road (FMNH 217230); Cedros Co., Coromandel Junction, Icacos (AMNH 127778); Icacos, SW peninsula (Hans Boos collection, unnumbered). VENEZUELA. Sucre: Elvécia, Monagas (Elvécia is a ranch on Mt. Turumiquire, up the valley from Cumanacoa, just over the divide in the Orinoco-río Amana drainage; altitude of ranch is 1770m, specimen altitudes 16501750 m) (CM 7976-77, 7979-81, 7984, 7998-8000, 8002); Delta Amacuro (MBUCV 399); Delta Amacuro, isla Guasina (MCNC 628, 3237); Mt. Turumiquire, Sucre-Monagas border (AMNH 29312).

Mem. Fund. La Salle de Cienc. Nat. 166

27

Recibido: 14 julio 2004 Aceptado: 8 enero 2007

†Joseph R. Bailey1 and Robert A. Thomas2 1 2

Department of Zoology, Duke University, Durham, NC 27706 USA. Center for Environmental Communications, School of Mass Communication and Department of Biological Sciences, Loyola University, P. O. Box 199, 6363 St. Charles Avenue, New Orleans, LA 70118-6195 USA. rathomas@loyno.edu