Herpetology Notes, volume 10: 53-57 (2017) (published online on 27 January 2017)

Discovery of the first male specimen of Tantilla hendersoni Stafford, 2004 (Squamata: Colubridae), from a new locality in central Belize

Erich P. Hofmann1,*, Russell J. Gray2, Larry David Wilson3 and Josiah H. Townsend1

Abstract. Tantilla hendersoni Stafford, 2004 was described based on a single female specimen from Cayo District, Belize, and is the only snake species considered to be endemic to the country. We report the discovery of a second specimen, the first male, of Tantilla hendersoni from a new locality in Stann Creek District, and provide a detailed morphological description of the specimen. We also discuss the distribution, conservation, and taxonomic status of the species.

Keywords: Tantilla hendersoni, Belize, Centipede snake, Central America, Stann Creek District

Introduction single female specimen (BMNH 2002.3) collected near Las Cuevas in Cayo District (Stafford, 2004), The genus Tantilla (Squamata: Colubridae) is and is considered the only species of snake endemic to currently composed of 63 species of small, semi- Belize (Stafford et al., 2010). Since the discovery of the fossorial snakes distributed throughout the Western holotype, one additional individual was photographed Hemisphere (Wilson & Mata-Silva, 2015; Batista et near the type locality, but not preserved (Stafford et al., al., 2016; Koch & Venegas, 2016). Given their size 2010: 385), and no additional specimens of this species and secretive nature, few specimens exist for many have become available for examination. taxa, and 13 of the 63 described species (20.6%) are On 30 August 2016, a single male Tantilla hendersoni known only from the holotype (Wilson & Mata-Silva, was collected during field work at the Toucan Ridge 2015; Batista et al., 2016). Three members of the genus Ecology and Education Society (TREES) Field Station have been reported from Belize (Stafford et al., 2010): near Middlesex in Stann Creek District, Belize (17.0508° T. cuniculator Smith, 1939; T. hendersoni Stafford, 2004; and T. schistosa (Bocourt, 1883). Tantilla moesta N, 88.5689° W; elevation 194 m; datum WGS84; Fig. 1). (Günther, 1863) was considered to occur in Belize by We provide the following morphological data and color Stafford (2004), but not reported for the country by notes for this specimen, the first adult male known for Stafford et al., (2010) or Wilson & Mata-Silva (2015), the species, and discuss the distribution, conservation, and no verified reports from Belize are known to us. and taxonomic status of the species. Tantilla hendersoni was described on the basis of a Methods and materials The Tantilla hendersoni specimen (CM 158957; Figs. 2 & 3) was found deceased in a funnel trap during a study comparing snake community assemblages across 1 Department of Biology, Indiana University of Pennsylvania, anthropogenically altered and undisturbed habitats. Indiana, Pennsylvania 15705–1081, USA The specimen was initially frozen, then later preserved 2 Toucan Ridge Ecology & Education Society, 27.5 using a 10% formalin solution before final storage in Hummingbird Highway, Stann Creek District, Belize 70% ethanol, and deposited in the Carnegie Museum 3 Centro Zamorano de Biodiversidad, Escuela Agrícola Panamericana Zamorano, Depto. Francisco Morazán, of Natural History (CM; Pittsburgh, Pennsylvania, Honduras USA). All measurements were taken to the nearest 0.1 * Corresponding author e-mail: [email protected] mm using digital calipers under a microscope, except 54 Erich P. Hofmann et al.

internasal common suture, with posterior termination at anterior edge of nostril; nasals divided, postnasal 0.79 times the length of prenasals; nostrils relatively large and in broad contact with pre- and post-nasals, with a small suture between both internasals and first supralabial; internasals 2.51 times as wide as they are long, contacting prenasal and postnasal laterally, their length 0.61 times as long as prefrontal common suture, their common suture 0.51 times as long as prefrontal common suture; prefrontals contacting preocular and postnasal laterally, their length 0.51 times snout length, their suture 0.40 times the frontal length; frontal 6- sided, 1.43 times longer than wide, in moderate contact with supraoculars (length of frontal-supraocular contact 0.58 times supraocular length, 1.37 times prefrontal- supraocular contact length); loreal absent; supraocular large, in contact with upper postocular; parietals 1.46 times longer than wide, their length 0.51 times the length of the head; 1/1 preoculars; 2/2 postoculars; supralabials 7/7; first supralabial in contact with rostral, preocular, and postocular; second in contact with postnasal and preocular; third in contact with preocular and orbit; fourth in contact with orbit and lower postocular; fifth Figure 1. Map of Belize showing known localities of Tantilla in contact with lower postocular and anterior temporal; hendersoni. The circle represents the type locality; the star sixth in contact with anterior temporal only; and seventh represents the new locality reported herein. in contact with anterior and posterior temporals; 6/7 infralabials with infralabial 4/5 being the largest, and first infralabial divided into two infralabials on the right side; on the left side, first infralabial in contact snout-vent length and tail length, which were taken to with mental and anterior chin shield, second and third the nearest 1 mm with a stiff ruler. in contact with anterior chin shield, fourth in contact with anterior and posterior chin shields; on the right Description side, first infralabial in contact with mental and anterior Tantilla hendersoni Stafford, 2004 chin shield, second only in contact with first and third infralabials, third and fourth in contact with anterior chin CM 158957: adult male. Dorsal scales in 15-15- shield, fifth in contact with anterior and posterior chin 15 rows, smooth throughout the length of the body; shield; mental 1.13 times longer than wide, in narrow apical pits absent; ventrals 157; cloacal scute divided; contact with anterior chin shields; anterior chin shields paired subcaudals 70, excluding one unpaired scale and large, 2.01 times longer than wide; posterior chin shield terminal spine; snout-vent length 269 mm, tail length 89 length 0.56 times the length of anterior chin shields; 2 mm, total length 358 mm, tail length/total length ratio pairs of gulars; 2 preventrals. 0.249. Head length (from posterior of the jaw to tip of The partially everted hemipenis extends to the margin the snout) 8.73 mm, head width 6.31 mm, eye diameter of the 4th and 5th subcaudal, and has a smooth pedicel; 1.45 mm (0.17 times the length of the head, 2.74 times numerous small spines surround the apical margin of its distance from the lip). the truncus; a single, large, hook-like spine is present Head is slightly broader than the attenuate body; on the asulcate surface of the truncus, with two large, snout extending beyond the anterior end of the lower hook-like spines flanking the sulcus spermaticus on the jaw; rostral wider than high, extending posteriorly sulcate surface; sulcus spermaticus centripetal at least to in dorsal view between internasals, portion of rostral the apical region; apical region not fully everted. visible in dorsal view 0.35 times the length of its Coloration in preservative (following Köhler, 2012; distance from the frontal, slightly smaller in length than color numbers in parentheses): ground color Sepia Discovery of the first male specimen of Tantilla hendersoni from central Belize 55

(286), fading to Vandyke Brown (281) laterally, with a narrow, Cream White (52) middorsal stripe arising 3.5 scale lengths behind the parietals, continuing unbroken to the terminal spine, and entirely confined to vertebral scale row; body is flanked by Smoky White (261) lateral stripes arising 4.5 scale lengths behind temporals, continuing unbroken nearly to the terminal spine, and comprising the upper half of scale row 3 and the lower half of scale row 4; Smoky White nuchal band contacting the parietals and extending approximately 1–1.5 scale lengths around neck, broken in the center by approximately 1 scale width, and separated from the middorsal stripe by approximately 3 scale lengths; venter is uniform Smoky White until approximately Figure 2. Tantilla hendersoni (CM 158957) dorsum (top) and midbody, where the extreme lateral edges of the ventrals venter (bottom). Scale bar = 10 mm. exhibit the Vandyke Brown ground color, continuing to the cloaca; upper paraventral scales dark, in contrast with lower paraventral scales exhibiting the Smoky White ventral color, continuing to the cloaca; the ventral side of the tail is uniform Smoky White, with the subcaudals exhibiting Vandyke Brown at the extreme edges; the anterior of the terminal spine is Smoky White, transitioning into Dark Grayish Olive (275) on the ventral posteriorly; dorsum of head is Sepia (286) with Brownish Olive (292) mottling extending to the tip of the snout; laterally, a Smoky White spot extends from the venter of the head to the dorsal level of the eye, separated from the nuchal band by approximately 1 scale length, partially encompassing supralabial 6, the anterior temporal, and lower postocular, and fully encompassing supralabial 5; a second Smoky White spot partially encompasses supralabials 2 and 3 and the majority of the postnasal, while fully encompassing the first supralabial; the rostral is Glaucous (272) with pale mottling on the ventral edges; the mental is anteriorly Vandyke Brown, Pale Buff (1) posteriorly; infralabials 1–3/1–4 and 5/6 anteriorly Vandyke Brown, with mottled edges and posteriorly Pale Buff; infralabials 4/5 anteriorly Pale Buff, posteriorly Vandyke Brown; gulars Pale Buff. The gallbladder of the specimen appears to have burst or been punctured during preservation, causing discoloration of the ventral scales in that area. CM 158957 differs from the holotype in the following aspects: 358 mm total length (272 mm total length in holotype); 157 ventrals and 70 subcaudals (opposed to 153 and 64, respectively); 6/7 infralabials (opposed to 6/6); broken nuchal band (opposed to unbroken); Figure 3. Tantilla hendersoni (CM 158957): dorsal (top), Vandyke Brown mottling on the lateral edges of the lateral (middle), and ventral (bottom) views of the head. Scale infralabials (as opposed to immaculate). bars = 1 mm. 56 Erich P. Hofmann et al.

Discussion locality (ca. 350 mm) … we suspect that BMNH 2002.3 probably represents a juvenile T. impensa Campbell Stann Creek District represents the second known (1998), and that differences between these two species locality for Tantilla hendersoni, approximately 58 km (size, color pattern features, and ventral scale numbers) NE of the type locality (Fig. 1) and at approximately 386 are attributable to a combination of geographic and m lower in elevation than previously known (holotype ontogenetic variation. As and when additional material collected at 580 m; Stafford 2004). Both the holotype becomes available, we expect T. hendersoni to be of T. hendersoni and CM 158957 were collected in relegated to the synonymy of T. impensa.” CM 158957 evergreen broadleaf forest (Stafford et al., 2010). While differs from T. impensa on the basis of ventral scales the holotype was collected in undisturbed primary (157 in CM 158957, opposed to the range for males forest, CM 158957 was collected in a reclaimed orange of 162–165; Wilson & Mata-Silva, 2015) and dark grove; this secondary growth has been left to regenerate mottling on the lateral edges of the ventrals at midbody for approximately 15 years, and is now dominated (opposed to no mottling; visible in Fig. 2: ventral view). by plants in the family Melastomataceae, heavy liana Additionally, CM 158957 maintains the same dark growth, and thick leaf litter. CM 158957 was found coloration in both the dorsolateral and ventrolateral during a sampling session that immediately followed fields, whereas T. impensa features lighter dorsolateral Hurricane Earl. This storm made landfall in Belize in segments when compared to their ventrolateral fields early August 2016, with winds of up to 128 km per hour (as in Stafford, 2004: 45). These characters were first and sustained heavy rains (Guardian US, 2016), causing used by Stafford (2004) to diagnose T. hendersoni widespread flooding across the country and greatly from T. impensa and supported by the new specimen, altering the forest structure on the TREES property. supporting the continued recognition of T. hendersoni The conservation status of Tantilla hendersoni as a valid taxon. remains poorly understood, as the lack of information Given the morphological similarities apparent in the for the species has prevented an accurate assessment. Tantilla taeniata species group, it is clear that further The IUCN Red List considers Tantilla hendersoni “Data taxonomic investigation involving morphological and, Deficient” (Johnson et al., 2014), and Stafford et al. particularly, molecular techniques is necessary, but the (2010) gave the species an Environmental Vulnerability lack of comparative material and sequence data remain as Score (EVS) of 18, placing it in the upper portion of challenging today as when T. hendersoni was originally the “High Vulnerability” category. Johnson et al. (2015) described. As more samples are found, however, the gave it an EVS of 16, placing it in the lower portion of potential for a full evaluation of the systematics of the the same category. These values are heavily weighted group grows. It is our hope that this finding will further by the lack of information on geographic and ecological renew interest in better understanding the evolutionary distribution for T. hendersoni. It is likely that this is a relationships of these secretive snakes. rare or uncommon species, as previously stated by Stafford (2004); however, given our finding here, it is Acknowledgements. We would like to thank the owners and also probable that the species has escaped detection in managing staff of the Toucan Ridge Ecology and Education other parts of its range, which appears to encompass at Society field station, Mathieu Charette and Vanessa Kilburn, for least the extent of the Maya Mountains. their assistance and use of equipment and facilities. Research Stafford (2004) considered Tantilla hendersoni to permits were obtained through the assistance of Edgar Correa of most closely resemble T. impensa and T. taeniata, the Belize Forestry Department. We also thank José Padial and and placed it as a member of the T. taeniata species Stephen Rogers (CM) for accessioning the specimen. group. This is the largest phenetic group of Tantilla, and currently consists of 22 species (Townsend et al., References 2013; Batista et al., 2016), although only one other Batista, A., Mebert, K., Lotzkat, S., and Wilson, L. D. (2016): A member of this group is found in Belize: T. cuniculator, new species of centipede snake of the genus Tantilla (Squamata: known from lowland elevations in the northern part of Colubridae) from an isolated premontane forest in eastern the country (Wilson & Mata-Silva, 2015). Six years Panama. Mesoamerican Herpetology 3: 949–960. Bocourt, M.F. (1883): Etudes sur les reptiles. Mission Scientifique after the original description, Stafford et al. (2010: 385) au Mexique et dans l’Amérique Centrale, Reserches zoologiques. called into question the taxonomic status of Tantilla Livriason 9: 529–592. hendersoni, stating: “in light of photographs we recently Campbell, J.A. (1998): Comments on the identities of certain examined from a second, larger specimen from the same Tantilla (Squamata: Colubridae) from Guatemala, with the Discovery of the first male specimen of Tantilla hendersoni from central Belize 57

descriptions of two new species. Scientific Papers, Natural History Museum, University of Kansas 7: 1–14. Guardian US. (2016): “Tropical storm Earl bears down on Mexico after tearing through Belize.” The Guardian, New York, New York, USA. Available at: https://www.theguardian.com/ world/2016/aug/04/hurricane-earl-belize-mexico-guatemala. Accessed: 18 October 2016. Günther, A. (1863): Third account of new species of snakes in the collection of the British Museum. Annals and Magazine of Natural History 3rd Series: 348–365. Johnson, J., Ariano-Sánchez, D., Acevedo, M. (2014): Tantilla hendersoni. The IUCN Red List of Threatened Species 2014: e.T203316A2763855. Accessed: 26 September 2016. Johnson, J.D., Mata-Silva, V., Wilson, L.D. (2015): A conservation reassessment of the Central American herpetofauna based on the EVS measure. Amphibian & Reptile Conservation 9: 1–94 (e100). Koch, C., Venegas, P. J. (2016): A large and unusually colored new snake species of the genus Tantilla (Squamata; Colubridae) from the Peruvian Andes. PeerJ 4: e2767; DOI 10.7717/peerj.2767 Köhler, G. (2008): Reptiles of Central America 2nd edition. Offenbach, Germany, Herpeton. Köhler, G. (2012): Color Catalogue for Field Biologists. Offenbach, Germany, Herpeton. Smith, H.M. (1939): Notes on Mexican reptiles and amphibians. Zoological Series of Field Museum of Natural History 24: 15–35. Stafford, P.J. (2004): A new species of Tantilla (Serpentes; Colubridae) of the taeniata group from southern Belize. Journal of Herpetology 38: 133–138. Stafford, P.J., Walker, P., Edgar, P., Penn, M.G. (2010): Distribution and conservation of the herpetofauna of Belize. In: Conservation of Mesoamerican Amphibians and Reptiles, p. 370–404. Wilson, L.D., Townsend, J.H, Johnson, J.D. Eds., Utah, USA, Eagle Mountain Publishing. Townsend, J.H., Wilson, L.D., Medina-Flores, M., Herrera-B., L.A. (2013): A new species of centipede snake in the Tantilla taeniata group (Squamata: Colubridae) from premontane rainforest in Refugio De Vida Silvestre Texíguat, Honduras. Journal of Herpetology 47: 191–200. Wilson, L.D., Mata-Silva, V. (2015): A checklist and key to the snakes of the Tantilla clade (Squamata: Colubridae), with comments on taxonomy, distribution, and conservation. Mesoamerican Herpetology 2: 418–498.

Accepted by Graham Walters