Abstract
The genus Thamnodynastes is the most diverse within the tribe Tachymenini, with an extensive and complex taxonomic history. The brief descriptions and lack of robust diagnostic characters are the main sources for identification errors and for the difficulty to assess the diversity estimates of the genus. The Thamnodynastes pallidus group was briefly designated to encompass the most arboreal species of the genus, with thinner bodies and longer tails: T. pallidus, T. longicaudus, T. sertanejo, and a fourth undescribed species. After its designation, no other paper addressed this group and its morphological variation, especially for the hemipenis, is still undetermined. After the analysis of all species of Thamnodynastes we were able to corroborate the distinctiveness of the T. pallidus group and to accurately diagnose its fourth species from the western portion of the Amazonia lowlands. The new species is distinguishable from all congeners, except T. sertanejo, by the absence of ventral longitudinal stripes, 17/17/11 dorsal scale rows, and dorsal dark brown blotches on the anterior third of the body. The new species is distinguished from T. sertanejo by the higher number of subcaudals, lower number of ventrals, and smaller body and head sizes. We also provide additional diagnostic features for the Thamnodynastes pallidus group, including new data on hemipenial variation. Finally, we briefly discuss the defensive behavior and morphological characters associated with arboreality in members of the T. pallidus species group.
References
Alencar, L.R.V., Martins, M., Burin, G. & Quental, T.B. (2017) Arboreality constrains morphological evolution but not species diversification in vipers. Proceedings of the Royal Society B: Biological Sciences, 284, 1–9.
https://doi.org/10.1098/rspb.2017.1775
Bailey, J.R., Thomas, R.A. & Silva Jr., N.J. (2005) A revision of the South American genus Thamnodynastes Wagler, 1830 (Serpentes, Colubridae, Tachymenini). I. Two new species of Thamnodynastes from Central Brazil and adjacent areas, with redefinition of and neotype designation for Thamnodynastes pallidus (Linnaeus, 1758). Phyllomedusa, 4 (2), 83–101.
https://doi.org/10.11606/issn.2316-9079.v4i2p83-101
Bailey, J.R. & Thomas, R.A. (2007) 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. Memoria de la Fundación La Salle de Ciencias Naturales, 166, 7–27.
Barbosa, A.R., Albuquerque, H.N. & Sousa, S.M. (2006) Descrição de desenvolvimento em cativeiro de uma nova espécie do gênero
Thamnodynastes (Wagler, 1830) (Serpente: Colubridae) da Caatinga Paraibana. Revista de Biologia e Ciencias da Terra, 6 (1), 73–83.Bartlett, R.D. & Bartlett, P. (2003) Reptiles and Amphibians of the Amazon. An Ecotourist’s Guide. University Press of Florida, Gainesville, Florida, 291 pp.
Bellini, G.P., Giraudo, A.R. & Arzamendia, V. (2014) Comparative ecology of three species of Thamnodynastes (Serpentes, Dipsadidae) in subtropical-temperate South America. The Herpetological Journal, 24 (2), 87–96.
Bergna, S. & Alvárez, B. (1993) Descripción de una nueva especie de Thamnodynastes (Reptilia: Serpentes, Colubridae) del nordeste argentino. Facena, 10, 5–18.
Bernarde, P.S., Kokobum, M.N.C. & Marques, O. (2000) Utilização de hábitat e atividade em Thamnodynastes strigatus (Günther, 1858) no sul do Brasil (Serpentes, Colubridae). Boletim do Museu Nacional, Nova Série, Zoologia, 428, 1–8.
Cei, J., Bergna, S. & Alvárez, Y.B. (1992) Nueva combinación para el género Thamnodynastes (Serpentes, Colubridae) de Argentina. Facena, 9, 123–134.
Coelho, R.D.F., Souza, K., Weider, A.G., Pereira, L.C.M. & Ribeiro, L.B. (2013) Overview of the distribution of snakes of the genus Thamnodynastes (Dipsadidae) in northeastern Brazil, with new records and remarks on their morphometry and pholidosis. Herpetological Notes, 6, 355–360.
Dixon, J.R. & Soini, P. (1977) The reptiles of the upper Amazon basin Iquitos region, Peru. II. Crocodilians, turtles and snakes. Contributions in Biology and Geology, Milwaukee Public Museum, 12, 1–91.
Dixon, J.R. & Soini, P. (1986) The reptiles of the upper Amazon basin, Iquitos region, Peru. 2nd ed. Milwaukee Public Museum, Milwaukee, Wisconsin,154 pp.
Dowling, H.G. (1951) A proposed method of expressing scale reductions in snakes. Copeia, 131–134.
https://doi.org/10.2307/1437542
Dowling, H.G. (1967) Hemipenes and other characters in colubrid classification. Herpetologica, 23 (2), 138–142.
Franco, F.L. & Ferreira, T.G. [“2002” (2003)] Descrição de uma nova espécie de Thamnodynastes Wagler, 1830 (Serpentes, Colubridae) do nordeste brasileiro, com comentários sobre o gênero. Phyllomedusa, 1, 57−74.
https://doi.org/10.11606/issn.2316-9079.v1i2p57-74
Franco, F.L., Ferreira, T.G., Marques, O.A.V. & Sazima, I. (2003) A new species of hood-displaying Thamnodynastes (Serpentes: Colubridae) from the Atlantic forest in southeast Brazil. Zootaxa, 334 (1), 1–7.
https://doi.org/10.11646/zootaxa.334.1.1
Franco, F.L., Trevine, V.C., Montingelli, G.G. & Zaher, H. (2017) A new species of Thamnodynastes from the open areas of central and northeastern Brazil (Serpentes: Dipsadidae: Tachymenini). Salamandra, 53 (3), 339−350.
Grazziotin, F.G., Zaher, H., Murphy, R.W., Scrocchi, G., Benavides, M.A., Zhang, Y. & Bonatto, S.L. (2012) Molecular phylogeny of the New World Dipsadidae (Serpentes: Colubroidea): a reappraisal. Cladistics, 1, 1−23.
https://doi.org/10.1111/j.1096-0031.2012.00393.x
Gorzula, S. & Ayarzagüena, J. 1995 (1996) Dos nuevas especies del género Thamnodynastes (Serpentes: Colubridae) de lostepuyes de la Guayana Venezolana. Publicación Asociación Amigos DonÞana, 6, 1–17.
Guedes, T.B., Nogueira, C. & Marques, O.A.V. (2014) Diversity, natural history, and geographic distribution of snakes in the Caatinga, Northeastern Brazil. Zootaxa, 3863 (1), 1–93.
https://doi.org/10.11646/zootaxa.3863.1.1
Harrington, S.M., de Haan, J.M., Shapiro, L. & Ruane, S. (2018) Habits and characteristics of arboreal snakes worldwide: arboreality constrains body size but does not affect lineage diversification. Biological Journal of the Linnean Society, 125, 61–71.
https://doi.org/10.1093/biolinnean/bly097
Harvey, M.B. & Embert, D. (2008) Review of Bolivian Dipsas (Serpentes: Colubridae) with comments on other South American species. Herpetological Monographs, 22, 54–105.
https://doi.org/10.1655/07-023.1
Jadin, R.C., Gutberlet, R.L. & Smith, E.N. (2010) Phylogeny, evolutionary morphology, and hemipenis descriptions of the Middle American jumping pitvipers (Serpentes: Crotalinae: Atropoides). Journal of Zoological Systematics and Evolutionary Research, 48 (4), 360–365.
https://doi.org/10.1111/j.1439-0469.2009.00559.x
Keogh, J.S. (1999) Evolutionary implications of hemipenial morphology in the terrestrial Australian elapid snakes. Zoological Journal of the Linnean Society, 125, 239–278.
https://doi.org/10.1111/j.1096-3642.1999.tb00592.x
QGIS Development Team (2019) QGIS Geographic Information System. Open source geospatial foundation project. Available from: http://qgis.osgeo.org (accessed January 2019)
Lacerda, J.V.A., Assis, B., Santana, D.J. & Feio, R.N. (2009) Anurans in bromeliads, Parque Estadual da Serra do Brigadeiro, state of Minas Gerais, southeastern Brazil. Check List, 5 (4), 800–806.
https://doi.org/10.15560/5.4.800
Lillywhite, H.B. & Henderson, R.W. (1993) Behavioral and functional ecology of arboreal snakes. In: Seigel, R.A. & Collins, J.T. (Eds.), Snakes: Ecology and Behavior. McGraw-Hill, New York, New York, pp. 1–49.
Manzanilla, J. & Sánchez, D. 2004 (2005) 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.
Myers, C.W. & Donnelly, M.A. (1996) A new herpetofauna from Cerro Yaviì, Venezuela: first results of the Robert G. Goelet American Museum-Terramar expedition to the northwestern Tepuis. American Museum Novittates, 3172, 1–56.
https://doi.org/10.1206/0003-0090(2001)261<0001:HOTYCM>2.0.CO;2
Myers, C.W. & McDowell, S.B. (2014) New taxa and cryptic species of Neotropical snakes (Xenodontinae), with commentary on hemipenes as generic and specific characters. Bulletin of the American Museum of Natural History, 385, 1–112.
Nóbrega, R.P., Montingelli, G.G., Trevine, V., Franco, F.L., Vieira, G.H., Costa, G.C. & Mesquita, D.O. (2016) Morphological variation within Thamnodynastes pallidus (Linnaeus, 1758) (Serpentes: Dipsadidae: Xenodontinae: Tachymenini). The Herpetological Journal, 26 (2), 165–174.
Pesantes, O.S. (1994) A method for preparing the hemipenis of preserved snakes. Journal of Herpetology, 28, 93−95.
https://doi.org/10.2307/1564686
Peters, J.A. (1964) Dictionary of Herpetology. Hafner, New York, 392 pp.
Pizzatto, L., Almeida-Santos, S.M. & Shine, R. (2007) Life-history adaptations to arboreality in snakes. Ecology, 88, 359–366.
https://doi.org/10.1890/0012-9658(2007)88[359:LATAIS]2.0.CO;2
R Core Team (2013) R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. Available from: http://www.R-project.org/ (accessed 3 March 2021)
Sabaj, M.H. (2020) Codes for Natural History Collections in Ichthyology and Herpetology. Copeia, 108 (2), 593–669.
https://doi.org/10.1643/ASIHCODONS2020
Schargel, W.E. & Castoe, T.A. (2003) The hemipenes of some snakes of the Semifossorial Genus Atractus, with Comments on Variation in the Genus. Journal of Herpetology, 37 (4), 718−721.
Sheehy, C.M., Albert, J.S. & Lillywhite, H.B. (2016) The evolution of tail length in snakes associated with different gravitational environments. Functional Ecology, 30, 1365–2435.
https://doi.org/10.1111/1365-2435.12472
Silva, W.S., Araújo. P.F., França, R.C., Pedrosa, I.M.M.C. & França, F.G.R. (2019) Offspring morphology and early growth of Thamnodynastes pallidus (Linnaeus, 1758) in the Brazilian Atlantic Forest (Serpentes; Thachymenini). Herpetology Notes, 12, 205–209.
Vidal, N., Dewynter, M. & Gower, D.J. (2010) Dissecting the major American snake radiation: a molecular phylogeny of the Dipsadidae Bonaparte (Serpentes, Caenophidia). Comptes Rendus Biologies, 333, 48–55.
https://doi.org/10.1016/j.crvi.2009.11.003
Zaher, H. (1999) Hemipenial morphology of the South American Xenodontine snakes, with a proposal for a monophyletic Xenodontinae and a reappraisal of colubroid hemipenes. Bulletin of the American Museum of Natural History, 240, 1−168.
Zaher, H. & Prudente, A.L.C. (1999) Intraspecific variation of the hemipenis in Siphlophis and Tripanurgos. Journal of Herpetology, 33 (4), 698−702.
https://doi.org/10.2307/1565589
Zaher, H. & Prudente, A.L.C. (2003) Hemipenes of Siphlophis (Serpentes: Xenodontinae) and techniques of hemipenial preparation in snakes: a response to Dowling. Herpetological Review, 34, 295−302.
Zaher, H., Grazziotin, F.G., Cadle, J.E., Murphy, R.W., Moura-Leite, J.C. & Bonatto, S.L. (2009) Molecular phylogeny of advanced snakes (Serpentes, Caenophidia) with an emphasis on South America xenodontines: a revised classification and descriptions of new taxa. Papéis Avulsos de Zoologia, 49, 115–153.
https://doi.org/10.1590/S0031-10492009001100001
Zaher, H., Yánez-Muñoz, M.H., Rodrigues, M.T., Graboski, R., Machado, F., Altamirano-Benavides, M., Bonatto, S.L. & Grazziotin, F.G. (2018) Origin and hidden diversity within the poorly known Galapagos snake radiation (Serpentes: Dipsadidae). Systematic and Biodiversity, 16 (7), 614–642.
https://doi.org/10.1080/14772000.2018.1478910