We report a range extension and new country record for Scarthyla vigilans in Trinidad, West Indies. The species

was previously known only from populations on mainland South America. We include notes on behavior, habitat and tadpole

development, and discuss the biogeographical significance of the species’ presence in Trinidad, particularly with respect to

consequences for understanding colonization events on this Caribbean island

Charles, S.P.

Downie, J.R.

Dye, R.F.

Murphy, J.C.

Ogilvy, V.

Rutherford, M.G.

Smith, Joanna

Thornham, Daniel

English

University of Worcester Research and Publications

Journal of species lists and distributionChec List574Notes oN GeoGraphic DistributioNISSN 1809-127X (online edition)© 2011 Check List and AuthorsOpen Access | Freely available at www.checklist.org.brScarthyla vigilans (Solano, 1971) is one of only two species in the genus Scarthyla Duellman and de Sá 1988. Originally described from the Maracaibo Lake basin in Venezuela (Solano 1971) and considered, until recently, to be endemic from this bioregion (La Marca 1992; Barrio-Amorós 1998). Recent reports extended the species distribution to include a greater extent of northwest Venezuela (Barrio-Amorós et al. 2006; Lampo et al. 2008) and northeast Colombia (Acosta-Galvis et al. 2006; Armesto et al. 2009). Rojas-Runjaic et al. (2008) record two further disjunct populations on the eastern Caribbean coast of Venezuela and in the Orinoco Delta. Here we report the first records of S. vigilans in Trinidad, West Indies, extending the known distribution of the species beyond mainland South America.In July 2006, JRD and JMS found many striped tadpoles (Figure 1), identified as S. vigilans (following the description in Suarez-Mayorga and Lynch 2001), in a coconut plantation irrigation channel on Columbia Road, South Trinidad (site A in Figure 2: 10°05’03.01” N, 61°53’26.14” W). Tadpoles were positioned vertically in the water column next to submerged grass stems at the edges of the channel. Nine tadpoles were collected and monitored from Gosner stage 36 to metamorphosis. Tadpoles weighed 0.26 ± 0.02 g (mean ± s.e.) and measured 29.7 ± 0.77 mm long (total length) at the start of metamorphosis, with ~64 % of this length represented by the tail. Duration of metamorphosis was 4.40 ± 0.13 days. Post-metamorphic froglets measured ~10mm SVL and had a translucent unmarked green dorsum with a single lateral stripe and a white venter (Figure 3).Additional S. vigilans tadpoles were collected at the same locality in July and August 2007, this time from Abstract: We report a range extension and new country record for Scarthyla vigilans in Trinidad, West Indies. The species was previously known only from populations on mainland South America. We include notes on behavior, habitat and tadpole development, and discuss the biogeographical significance of the species’ presence in Trinidad, particularly with respect to consequences for understanding colonization events on this Caribbean island.1 Anglia Ruskin University, Department of Life Sciences. Cambridge CB1 1PT, U.K. 2 University of Glasgow, College of Medical, Veterinary and Life Sciences, School of Life Sciences. Glasgow G12 8QQ, U.K.3 Amazonia, Strathclyde Country Park. Motherwell ML1 3RT, U.K.4 University of Manchester, Faculty of Life Sciences. Manchester M13 9PL, U.K.5 University of Cambridge, Department of Zoology. Cambridge CB2 3EJ, U.K.6 University of the West Indies, Department of Life Sciences. St. Augustine, Trinidad. 7 Howard University, Department of Biology. Washington, D.C. 20059 U.S.A.8 Division of Amphibians and Reptiles, Field Museum of Natural History. Chicago, IL 60604 U.S.A. * Corresponding author. E-mail: frojo2525@hotmail.comJoanna M. Smith 1*, J. Roger Downie 2, Rebecca F. Dye 3, Victoria Ogilvy 4, Daniel G. Thornham 5, Michael G. Rutherford 6, Stevland P. Charles 7 and John C. Murphy 8Amphibia, Anura, Hylidae, Scarthyla vigilans (Solano, 1971): Range extension and new country record for Trinidad, West Indies, with notes on tadpoles, habitat, behavior and biogeographical significanceCheck List | Volume 7 | Issue 5 | 2011Figure 1. (A) Scarthyla vigilans tadpole collected from Fullarton area, with (B) close-up of mouthpart structure (Photos: V. Ogilvy).Figure 2. Current known distribution of Scarthyla vigilans in Trinidad (A-E) in relation to closest known mainland population in Venezuela (F). Locations: (A) Columbia Road (B) Bowen Trace (C) Southern Main Road (D) Austin Trace (E) Bonasse Swamp (F) Orinoco Delta (Rojas-Runjaic et al.  2008).A B575Smith et al. | First record of Scarthyla vigilans for TrinidadCheck List | Volume 7 | Issue 5 | 2011Figure 3. Scarthyla vigilans metamorph, Austin Trace (Photo: J.C. Murphy).vegetation-choked drainage ditches on the edge of flooded grassland growing beneath the coconut plantation (Figure 4A). Tadpoles were found at water margins where vegetation was thickest and were netted together with tadpoles of Dendropsophus microcephalus, D. minusculus and Scinax gr. ruber. Twelve tadpoles (Gosner stages 24-36) were collected and deposited in the University of Glasgow’s Hunterian Museum (GLAHM 140267, GLAHM 140269).On July 31 2007, between 15:00 and 17:30 h, RFD, DGT, JMS heard adult S. vigilans males calling from a man-made pond (Figure 4B) along the Bowen Trace, southern Trinidad (site B in Figure 2: 10°06’10.92” N, 61°46’49.58” W). Calling activity intensified in breezy conditions and the scratchy twittering call, cricket-like individually, sounded en masse like wind blowing through grass. When approached, frogs would either dive into the water or quickly jump across the water surface and proved difficult to capture. A single frog measuring 17.5 mm SVL (Figure 5A) was collected from this site. No tadpoles were found in several sweeps of the edge margins. Synbranchus marmoratus elvers, cyprinodontid fish Rivulus hartii and juvenile caiman (Caiman crocodilus) were present at the site. Sympatric frog species at this site included: Pseudis paradoxa, and Sphaenorhynchus lacteus.Between 19:30 and 20:30 h on August 06 2007, calling was also heard at the Columbia Road site where the tadpoles had first been found. Calling males were found sitting on leaves of low-growing swamp grass in a flooded field. Four frogs were collected, of which three were calling at time of collection, and measured 16.2 (Figure 5B), 16.5 (Figure 5C) and 16.9 (Figure 5D) mm SVL. Calling frogs were pale green at time of collection, with faint dorsal stripes, a dark lateral stripe and indistinct leg markings (i.e. Figure 5C). One larger silent frog, darker and more strongly marked, was also collected, measuring 18.7 mm SVL (Figure 5E). All frogs had an unmarked, cream-white venter (i.e. Figure 5F). Specimens were deposited in the University of Glasgow’s Hunterian Museum: GLAHM 140268 (immature female, Bowen Trace); GLAHM 140270 (3 males, 1 female, Columbia Road).Figure 4. Scarthyla vigilans habitat at (A) Fullarton and (B) Bowen Trace, Trinidad. (Photos: J.M. Smith).On June 23 2010, between 17:00 and 20:00h MGR, SPC and JCM searched streams and wetlands in the area south of the Southern Main Road between Bonasse and Erin Road. The area is a mosaic of agroecosystems (coconut, rice, cocoa) and herbaceous swamp. Scarthyla adults were first collected about 17:00 h along a weed-choked ditch and its inundated floodplain (site C in Figure 2: 10°05’42.74” N, 61°48’58.03” W). Adult frogs were sitting on stems and leaves from the water level to ~0.5 m above the water. At a second location on Austin Trace (site D in Figure 2: 10°05’43.65” N, 61°47’23.48” W), a large chorus of S. vigilans was present in the emergent vegetation at the edge of a flooded pool. New metamorphs were also present. Dendropsophus microcephalus and Engystomops pustulosus frogs were also calling at the site and we noted  presence of potential predators such as Caiman crocodilus and the cat-eyed night snake, Leptodeira annulata ashmeadi. Nine voucher specimens were deposited in the University of the West Indies Museum: (UWITT 2010.21.10, 3 specimens preserved in formalin / UWITT 2010.21.11, six specimens preserved in alcohol).On 12th July 2010 between 17:00 and 18:00 h, JRD (and colleagues) returned to Austin Trace to check for the presence of S. vigilans tadpoles. Scarthyla adults were heard calling from vegetation at the margins of flooded ditches on both sides of the track. Using large hand nets, we captured many Scinax gr. ruber tadpoles on the south side and many Scarthyla tadpoles on the north side. On the 14th July 2010 between 09:00 and 10:00 h, two of us (JRD, VO) searched Bonasse Swamp (site E in Figure 2: 10°05’42.74” N, 61°48’58.03” W); Scarthyla vigilans adults were calling even at this time. Scarthyla tadpoles were the most abundant species caught, with Scinax gr. ruber and Dendropsophus microcephalus also common. A sample of Scarthyla tadpoles was deposited in the University of the West Indies Museum (UWITT 2010.21.23).These first records for Trinidad extend the distribution of S. vigilans out of mainland South America and are of particular interest in light of the recent discovery of a population of the species in the Orinoco Delta in Venezuela A B576Check List | Volume 7 | Issue 5 | 2011Smith et al. | First record of Scarthyla vigilans for TrinidadFigure 5. Scarthyla vigilans, adult frogs from southern Trinidad: (A) Immature female collected from Bowen Trace, 2007: GLAHM 140268 (B-D) Male frogs collected from Columbia Road, 2007: GLAHM 140270 (E-F) Female frog collected from Columbia Road, 2007: GLAHM 140270. For SVL measurements please see text. (Photos: J.M. Smith).(Rojas-Runjaic et al. 2008). Figure 2 shows the distribution of the known population in Trinidad relative to this recent range-extension. The Orinoco discharge is one of the single biggest influences on the shoreline of Trinidad in terms of sediment delivery (Kenny 2002). During the wet season the volume of freshwater entering the Gulf of Paria from both the Orinoco and Amazon can result in up to an 80% reduction in salinity levels (Alkins and De Souza 1984; Read 1987) creating potentially more favorable conditions for colonizing amphibians and ample opportunity for mainland fauna to colonize via floating rafts of vegetation.The discovery of a new species of amphibian for Trinidad on the southwestern Cedros peninsula is intriguing considering other ‘recent’ amphibian discoveries in the country. The three most recently recorded amphibian species: Dendropsophus minusculus, Leptodactylus nesiotus (Read 1987) and Leptodactylus macrosternum (Kenny 1977) are all exclusively found in this area. Leptodactylus nesiotus is thought to be a Trinidad endemic (Heyer 1994) but both D. minusculus and L. macrosternum have Venezuelan distributions, including the Orinoco Delta (Acosta-Galvis et al. 2008; Heyer et al. 2008). It has been proposed that the presence of both in Trinidad may be representative of recent colonization events from Venezuela (Kenny 1977; Read 1987).A BC ED FIt is difficult to know how recently this ‘colonization’ has taken place in Trinidad. It is possible that the species has been present for a while; certainly the numbers in which it is now present in the South appear considerable. Rojas-Runjaic et al. (2008) discuss the lack of previous records from the historically well sampled areas in Venezuela in which they were working. They suggest that their recent discovery in those areas is either due to an ongoing geographic expansion by the species or that they may have been under-recorded due to their inconspicuous advertisement calls, particularly where other amphibians with louder calls are active. Armesto et al. (2009) and Rojas-Runjaic et al. (2008) both record Scarthyla vigilans in sympatry with Dendropsophus microcephalus and Scinax gr. ruber, species with loud, shrill calls. In Trinidad, Scarthyla vigilans were found sympatrically with Dendropsophus minusculus, D. microcephalus, Engystomops pustulosus, Sphaenorhynchus lacteus, Scinax gr. ruber and Pseudis paradoxa, all of which have louder calls than the obscure, insect-like trill of Scarthyla vigilans. It is possible therefore that, in spite of regular night surveys by teams from the University of Glasgow in the South of Trinidad over the past twenty years, the frog has been missed (particularly if burrowing behaviour observed in frogs under captive conditions (JMS, RFD, DGT, personal observations) is 577Check List | Volume 7 | Issue 5 | 2011Smith et al. | First record of Scarthyla vigilans for TrinidadReceived: January 2011Last Revised: April 2011Accepted: May 2011Published online: September 2011Editorial responsibility: Pedro L. V. PelosoLiterature CitedAlkins, M. and G. De Souza. 1984. Two new freshwater fish records for Trinidad and some comments on the zoogeography of the Southern peninsula. Living World: Journal of the Trinidad Field Naturalists’ Club 1984: 8-12.Acosta-Galvis, A.R., C. Huertas-Salgado and M. Rada. 2006. Aproximación al conocimiento de los anfibios en una localidad del Magdalena medio (Departamento de Caldas, Colombia). Revista de la Academia Colombiana de Ciencias 30 (115): 291-304.Acosta-Galvis, A., R. MacCulloch, J. Manzanilla and J. Hardy. 2008. Dendropsophus minusculus. IUCN 2010. IUCN Red List of Threatened Species. Version 2010.4. Electronic Database accessible at http://www.iucnredlist.org/. Captured July 2010.Armesto, O., J.B. Esteban and R. Torrado. 2009. Fauna de anfibios del Municipio de Cúcuta, Norte de Santander, Colombia. Herpetotropicos 5 (1): 57-63.Acknowledgments: We thank Nadra Nathai-Gayan and David Boodoo of Trinidad Governmental Wildlife Division for permissions to work in the country. For “frogging” help thanks to Naomi Barron and University of Glasgow Trinidad Expedition students (2006/07/10): including Stephanie Ballantyne, Tom Deas, Gillian Carfrae, Leoni de Wert, Zara Gladman, Alison Hunter, Jan Lupton, Matt MacDonald, Vicki Macnab, Darryl McLennan, Amy McKellar and Fraser Murdoch. We also thank Ronnie Hernandez of Simla Research Station, Asa Wright Nature Centre for his help and support. JMS, JRD and DGT were supported by field grants from the Carnegie Trust for the Universities of Scotland. RFD was supported by a Studentship Project Grant from Chester Zoo and an Explorer’s Club Youth Activity Fund Grant.typical). However, the species is one of few in Trinidad which exhibits diurnal calling activity (also reported by Barrio-Amoros et al. 2006; Armesto et al. 2009) and the areas where tadpoles were found in 2006/07 and 2010 have been systematically netted by some of us (JRD, JMS, VO) for around ten years and neither the diurnally active adults nor the very distinctive tadpoles have been found before. This supports the idea that the species has arrived in Trinidad relatively recently or it may simply suggest a recent localized movement. Genetic work to compare mainland populations with Trinidad’s frogs may help to clarify the timescale involved. Furthermore, considering the seemingly fragmented distribution of the currently described populations, genetic analysis of the separated populations is desirable to assess conservation needs for this species.Barrio-Amorós, C.L. 1998. Sistemática y Biogeografía de los anfibios (Amphibia) de Venezuela. Acta Biologica Venezuelica 18: 1-93.Barrio-Amorós, C.L., A. Diaz, J.J. Mueses-Cisneros, E. Infante and A. Chacón. 2006. Hyla vigilans Solano, 1971, a second species for the genus Scarthyla, redescription and distribution in Venezuela and Colombia. Zootaxa 1349: 1-18. Heyer, W.R. 1994. Variation within the Leptodactylus podicipinus-wagneri complex of frogs (Amphibia: Leptodactylidae). Smithsonian Contributions to Zoology 546: 1-124.Heyer, R., J. Langone, E. La Marca, C. Azevedo-Ramos, I. di Tada,  D. Baldo, E. Lavilla, N. Scott, L. Aquino and J. Hardy. 2008. Leptodactylus ocellatus. IUCN 2010. IUCN Red List of Threatened Species. Version 2010.4. Electronic Database accessible at http://www.iucnredlist.org/. Captured July 2010.Jowers, M.J., B.L. Cohen and J.R. Downie. 2008. The cyprinodont fish Rivulus (Aplocheiloidei: Rivulidae) in Trinidad and Tobago: molecular evidence for marine dispersal, genetic isolation and local differentiation. Journal of Zoological Systematics and Evolutionary Research 46 (1): 48-55.Kenny, J.S. 1969. The amphibia of Trinidad. Studies on the Fauna of Curacao and other Caribbean Islands 103: 1-77.Kenny, J.S. 1977. The amphibia of Trinidad: an addendum. Studies on the Fauna of Curacao and other Caribbean Islands 51: 92-95.Kenny, J.S. 2002. The changing coastline of the Cedros Peninsula, Trinidad. Living World: Journal of the Trinidad Field Naturalists’ Club 2002: 1-7.La Marca, E. 1992. Catálogo taxonómico, biogeográfico y bibliográfico de las ranas de Venezuela. Cuadernos Geográficos 9: 1-197.Lampo, M., S. Sánchez, A. Nicolás, M. Márquez, F. Nava-González, C.Z. García, M. Rinaldi, A. Rodríguez-Contreras, F. León, B.A. Han and A. Chacón-Ortiz. 2008. Batrachochytrium dendrobatidis in Venezuela. Herpetological Review 39(4): 449-454.Lynch, J.D. 2006. The tadpoles of frogs and toads found in the lowlands of northern Colombia. Revista de la Academia Colombiana de Ciencias 30 (116): 443-457.Read, V.M.J. 1987. Two new anurans from Trinidad. Bulletin Chicago Herpetological Society 21: 29-31.Rojas-Runjaic, F.J.M., C.L. Barrio-Amorós, C. Molina, J.C. Señaris and I.C. Fedón. 2008. Amphibia, Anura, Hylidae, Scarthyla vigilans: Range extensions and new state records from Delta Amacuro and Miranda states, Venezuela. Check List 4(3): 301-303.Solano, H. 1971. Una nueva especie del género Hyla (Amphibia: Anura) de Venezuela. Acta Biologica Venezuelica 1971: 211-218.Suarez-Mayorga, A.M. and J.D. Lynch 2001. Redescription of the tadpole of Hyla vigilans (Anura: Hylidae) and notes about possible taxonomic relationships. Caribbean Journal of Science 37 (1-2): 116-119.

Amphibia: Anura: Hylidae Scarthyla vigilans (Solano 1971): Range Extension and New Country Record for Trinidad, W.I. With Notes on Tadpoles, Habitat, Behaviour and Biogeographical Significance.

Amphibia: Anura: Hylidae Scarthyla vigilans (Solano 1971): Range Extension and New Country Record for Trinidad, W.I. With Notes on Tadpoles, Habitat, Behaviour and Biogeographical Significance.

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