SHORTER COMMUNICATIONS Journal of Herpetology, Vol. 45, No. 2, pp. 167–168, 2011 Copyright 2011 Society for the Study of Amphibians and Reptiles
Rediscovery of the Grenada Bank Endemic Typhlops tasymicris (Squamata: Typhlopidae) MEL JOSE´ RIVERA RODRI´GUEZ,1 EHREN J. BENTZ,2,3 DANIEL P. SCANTLEBURY,4 REBECCA R. JOHN,5 DANIEL P. QUINN,6 JOHN S. PARMERLEE JR.,7 ROBERT W. HENDERSON,8 AND ROBERT POWELL9,10 1
Department of Biology, University of Puerto Rico, Mayagu¨ez, Puerto Rico 00681 2 Feather River College, Quincy, California 95971 USA Department of Biology, University of Rochester, Rochester, New York 14627-0211 USA 5 Departments of Environmental Studies and Biology, University of California, Santa Cruz, California 95064 USA 6 Department of Biology, Truman State University, Kirksville, Missouri 63501 USA 7 Department of Biology, Johnson County Community College, Overland Park, Kansas 66210 USA 8 Section of Vertebrate Zoology, Milwaukee Public Museum, Milwaukee, Wisconsin 53233 USA 9 Department of Biology, Avila University, Kansas City, Missouri 64145 USA 4
ABSTRACT.—Typhlops tasymicris was known previously from only two specimens, both immature females collected on Grenada in 1968. In June 2010, we rediscovered the species on Union Island, St. Vincent and the Grenadines, where we encountered five individuals (and captured four) on the forested slopes above Chatham Bay. The new specimens agree closely with the two previously reported individuals for all scale characters and coloration, but they differ in sizes and proportions. At least two of the new specimens are adults, but all seem to be females. This first record of a typhlopid snake in the Grenadines suggests a greater range than indicated by the earlier specimens. Although suitable habitat occurs nowhere else on Union Island, the species could occur elsewhere in the Grenadines where relatively mature forests persist. DNA sequence data clearly show a closer affinity with South American species than with any West Indian congeners. Forty-three years have passed since the only known specimens of Typhlops tasymicris were found on Grenada, West Indies. Thomas (1974) described the species on the basis of a single specimen (UF 21547) collected in 1968, and Wallach (2000) provided data on a second specimen (MVZ 84060), also an immature female collected in 1968. Efforts to find additional specimens included searches and questioning residents, some of whom indicated that they had encountered wormlike snakes. Despite 20 years of such effort, no new information has emerged. All data included in compendia (Thomas, 1976, 1989; Schwartz and Henderson, 1991; Germano et al., 2003; Yorks et al., 2003; Henderson and Berg, 2006; Henderson and Powell, 2009) are based on one or both of the previously known specimens. Herein, we describe the rediscovery of the species on the basis of five snakes found on Union Island, St. Vincent and the Grenadines. MATERIALS AND METHODS From 4 to 22 June 2010, we conducted surveys of the forest floor on the north- and west-facing hillsides above Chatham Bay, Union Island (12u35.8009N, 61u26.7009W), at elevations of 31–234 m on the northwestern slope of Mt. Taboi (Fig. 1). We recorded ground-level air temperatures in the field by laying a Fluke 51 digital thermometer with type-K thermocouples (Fluke Corp., Everett, WA) on the substrate at the exact spot where the animal was detected. We used a Garmin ETrex Venture HC handheld GPS device accurate to approximately 15 m (Garmin International, Inc., Olathe, KS) for locations and elevations. We preserved specimens in 85% ethanol for subsequent DNA extraction. We measured total length to the nearest millimeter with a clear plastic scale and tail length to the nearest 0.1 mm by using electronic calipers (Mitutoyo Corp., Aurora, IL). We also counted scales or evaluated characters as described in Thomas (1974, 1976).
FIG. 1. The circle marks the location where Typhlops tasymicris was rediscovered on the west-facing slope above Chatham Bay, Union Island, St. Vincent and the Grenadines. Contour interval 5 30.5 m (100 ft).
DISCUSSION Union Island is characterized by a relatively dry climate with an average annual rainfall of 1,000 mm (Daudin, 2003). The old secondary forest above Chatham Bay (Fiard, 2003) has an average canopy height
RESULTS On 5 June 2010, on the west-facing slope above Chatham Bay (Fig. 1), we collected four T. tasymicris, including adults (Fig. 2), and we saw another T. tasymicris that eluded capture. All were under cover in moist substrate, with an average ground-level temperature of 28.1 6 0.2uC at elevations of 159–179 m. Two T. tasymicris were found under deep leaf litter, two (including the individual that escaped) were under rocks, and one was under a termite mound. The four new specimens agree closely with those collected previously for all scale characters and coloration (Thomas, 1974, 1976): 20-20-20 scale rows, nasal divided, inferior suture contacting second supralabial, lacking postnasal concavity, one postocular, T-III supralabial imbrication pattern, parietals and occipitals transversely enlarged, 13 middorsal scale rows pigmented). However, the new specimens differ in size and proportions (Table 1). 3
Present address: Department of Biology, Oregon State University, Corvallis, Oregon 97331 USA 10 Corresponding Author: E-mail:
[email protected]
FIG. 2. Adult female Typhlops tasymicris (MPM 33551) from the westfacing slope above Chatham Bay, Union Island, St. Vincent and the Grenadines. Photograph by Mel Jose´ Rivera Rodrı´guez. Color reproduction supported by the Thomas Beauvais Fund.
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TABLE 1. Sizes, proportions, and meristics of the six known specimens of Grenada Blind Snakes (Typhlops tasymicris). University of Florida (UF) 21547 is the holotype (Thomas, 1974) and Museum of Vertebrate Zoology (MVZ) 84060 is the second known specimen (Wallach, 2000), both are from Grenada. Milwaukee Public Museum (MPM) 33551–2 and 33991–2 are from Union Island on the Grenada Bank. Specimen Character Sex
Total length (TL), mm Tail length (TA), mm TL/TA Middorsal scales Subcaudals
UF 21547 Immature female
181 2.6 70 429 5
MVZ 84060
MPM 33551
Immature female
196 2.5 78 427 7
of 10–15 m and is characterized by loose soil, numerous rocky outcrops, and deep leaf litter. Comparable habitat is not found anywhere else on the island. This forested area is one of the last remaining mature secondary forests in the Grenadines. This report represents the first record of a typhlopid snake in the Grenadines. This discovery extends the range of the species into the central Grenadines, which are part of the Grenada Bank, and suggests the possibility of a much greater range than indicated by the two previously known specimens. Because the species has now been recorded from Grenada and Union Island, T. tasymicris might very well occur on other Grenadine islands with some remaining stands of relatively mature forest. Carriacou, which is situated between Union and Grenada, is a likely candidate. Sphaerodactylus kirbyi, previously known only from the northern Grenadines (Hite et al., 2008), was recently discovered on Union Island (J. P. Burgess, pers. comm., 15 May 2010), where it occurs in the same habitat as T. tasymicris, and on Carriacou (Boone and Scantlebury, unpubl. data). The phylogenetic relationships of this species are poorly known, and it was not included in the latest molecular phylogeny of typhlopid snakes by Vidal et al. (2010). Thomas (1974, 1976), based on morphological evidence, indicated that T. tasymicris resulted from a recent dispersal event into the southern Lesser Antilles, that T. tasymicris is a very close relative of T. trinitatus from Trinidad and Tobago, and that both species are related to T. lehneri of northern South America. Dixon and Hendricks (1979) proposed a Caribbean Arc group that included those three species; all Central American species; and species from Cuba, the Cayman Islands, and the Bahamas (the T. biminiensis species group) based on head scalation. Thomas (1989) included a cladogram showing affinity between T. tasymicris and the T. biminiensis species group. However, like a number of other taxa from the southern Lesser Antilles (e.g., the Anolis roquet species group, Gonatodes daudini), DNA sequence evidence (S. B. Hedges, pers. comm., 20 August 2010) from the newly collected material clearly shows that T. tasymicris is more closely related to South American species (T. brongersmianus and T. reticulatus) than to any other West Indian taxa. Acknowledgments.—S. B. Hedges provided data from DNA sequencing and reviewed an earlier draft of this manuscript. C. Spencer arranged for the loan of the MVZ specimen. Permits to conduct research on Union Island were issued by B. Johnson, Director, Department of Forestry, St. Vincent and the Grenadines. Protocols were approved by the Avila University Animal Care and Use Committee (IACUC 2007-01). Fieldwork was funded by a grant from the National Science Foundation (USA) to RP (DBI-0851610).
MPM 33552
MPM 33991
Female
Female
Female
263 3.2 82 417 8
232 3.3 70 429 7
218 3.6 60 408 8
MPM 33992 Immature (?) female
190 2.3 83 426 7
LITERATURE CITED DAUDIN, J. (ED.). 2003. A Natural History Monograph of Union Island. De´sormeaux, Martinique. DIXON, J. R., AND F. S. HENDRICKS. 1979. The wormsnakes (Family Typhlopidae) of the Neotropics, exclusive of the Antilles. Zoologische Verhandelingen 173:1–39. FIARD, J.-P. 2003. The phytosociologic and dynamic outline of the main forestry groups of Union Island. In J. Daudin (ed.), A Natural History Monograph of Union Island, pp. 47–53. De´sormeaux, Martinique. GERMANO, J. M., J. M. SANDER, R. W. HENDERSON, AND R. POWELL. 2003. Herpetofaunal communities on Grenada: a comparison of altered sites, with an annotated checklist of Grenadian amphibians and reptiles. Caribbean Journal of Science 39:68–76. HENDERSON, R. W., AND C. S. BERG. 2006. The herpetofauna of Grenada and the Grenada Grenadines: Conservation concerns. Applied Herpetology 3:197–213. HENDERSON, R. W., AND R. POWELL. 2009. Natural History of West Indian Reptiles and Amphibians. University Press of Florida, Gainesville. HITE, J. L., D. S. STEINBERG, AND R. POWELL. 2008. Sphaerodactylus kirbyi. Catalogue of American Amphibians and Reptiles 852:1–2. SCHWARTZ, A., AND R. W. HENDERSON. 1991. Amphibians and Reptiles of the West Indies: Descriptions, Distributions, and Natural History. University of Florida Press, Gainesville. THOMAS, R. 1974. A new species of Lesser Antillean Typhlops (Serpentes: Typhlopidae). Occasional Papers of the Museum of Zoology, Louisiana State University (46):1–5. ———. 1976. Systematics of Antillean Blind Snakes of the Genus Typhlops (Serpentes: Typhlopidae). Unpubl. Ph.D. diss., Louisiana State University, Baton Rouge. ———. 1989. The relationships of Antillean Typhlops (Serpentes: Typhlopidae) and the description of three new Hispaniolan species. In C. A. Woods (ed.), Biogeography of the West Indies: Past, Present, and Future, pp. 409–432. Sandhill Crane Press, Gainesville, FL. VIDAL, N., J. MARIN, M. MORINI, S. DONNELLAN, W. R. BRANCH, R. THOMAS, M. VENCES, A. WYNN, C. CRUAUD, AND S. B. HEDGES. 2010. Blindsnake evolutionary tree reveals long history on Gondwana. Biology Letters 6:558–561. WALLACH, V. 2000. Typhlops tasymicris (Grenada Blind Snake). Maximum length and second known specimen. Herpetological Review 31:180. YORKS, D. T., R. W. HENDERSON, AND R. POWELL. 2003. Typhlops tasymicris. Catalogue of American Amphibians and Reptiles 780:1–2. Accepted: 7 October 2010.
