Tuesday, July 28, 2020

[Herpetology • 2020] Tropidophis steinleini • A New Species of Tropidophis (Squamata: Tropidophiidae) and Molecular Phylogeny of the Cuban Radiation of the Genus


Tropidophis steinleini  
 Díaz & Cádiz, 2020

Photos: L. M. Díaz. 

ABSTRACT
Cuba has the highest diversity of snakes in the genus Tropidophis, representing 53 % of all the known species. Tropidophis steinleini sp. nov. is described from the eastern region of Cuba, raising the number of species to 17 in this archipelago. The new species is most closely related to T. wrighti, T. spiritus and T. morenoi. We discuss the phylogenetic relationships of this new species and other species of the genus in Cuba, based on molecular data, and classified them within three species groups according to the obtained tree topology.

Keywords: Caribbean Islands, snakes, dwarf boas, DNA, classification, species groups

Figure 1. Tropidophis steinleini sp. nov., two different views of the female holotype MNHNCu 5079 in life. Photos: L. M. Díaz.

Maximum likelihood phylogeny of sampled snakes of the genus Tropidophis based in two mitochondrial and one nuclear gene, showing the three major Cuban clades and the position of Tropidophis steinleini sp. nov. The nominal, representative species of each group: T. pardalis, T. melanurus and T.  maculatus, are respectively illustrated. Voucher’s catalog numbers are listed in Appendix 1. Tree is rooted with T. haetianus (from Hispaniola). Black circles: bootstrap = 100; yellow circle: bootstrap 81–99; no circle: bootstrap ≤ 80. Photos by L. M. Díaz. 

Tropidophis steinleini sp. nov.

Diagnosis. Species in the Tropidophis pardalis species group as defined in the herein-presented molecular phylogeny (see  Fig. 3, also Fig. 6  for  species comparisons, and  the  Discussion). Body  slender  and  laterally compressed;  head  distinctive  from  neck;  6  rows  of  dark  blotches around body; some of the paravertebral and lateral blotches are longitudinally fused; 23 scale rows around midbody; 188 ventral scales; an evident groove above the supralabial scales; first supralabial slightly higher than second. Regarding morphology and the phylogenetic relationships, the new species is most similar to T. spiritus, T. morenoi and T. wrighti (Table I; Fig. 6 F, G, H, respectively). In the three species the first supralabial scale is much lower than second one; the head is gradually tapered in profile compared with the flat head top and a higher snout of the new species; a groove over the supralabial scales is absent (Fig. 2). T. wrighti has four rows of large blotches around body instead of 6, contrasting on a homogenous gray to white-colored background (Fig. 6H); some of the blotches are fused at the mid-dorsum but not in a distinctive longitudinal way; ventral scale counts (192–222) are higher than in Tropidophis steinleini sp. nov. T. morenoi and T.  spiritus have 183–200 ventral  scales, widely overlapping with Tropidophis steinleni sp. nov., and similar coloration considering that the three species have 6 rows of blotches around the midbody and pale lower flanks; however, the head shape is different (Fig. 2) as mentioned above. The snout is slightly shorter in available T. spiritus and T. morenoi (30–33 % of head length, x = 31 %, n = 7) compared with Tropidophis steinleini sp. nov. (34 %); paravertebral blotches are not longitudinally enlarged in T. spiritus and T. morenoi (Fig. 6 F, G), but instead some transversal fusion may exist, giving them a banded appearance (a condition not present in the new species); head is darker in T. spiritus and T. morenoi, with more evident and contrasting pattern of blotches and stripes which is somewhat diffuse or barely evident in Tropidophis steinleini sp. nov.

Etymology. The species is named with gratitude, after our German colleague Claus Steinlein, for his support of the authors’ herpetological research in Cuba.


 Figure 6. Cuban snakes of the Tropidophis pardalis species group. 
A,  T. pardalis, female, from Boyeros, La Habana Province; B, T.  pardalis, female, from Soroa, Candelaria, Artemisa Province; C, T. xanthogaster, male, from La Bajada, Guanahacabibes, Pinar  del  Río  Province;  D, T.  hardyi,  male,  from  Río  Jutía,  Guajimico,  Cienfuegos  Province; 
E, Tfuscus,  female, from Altiplanicie de El Toldo, Humboldt National Park, Holguín province; F, T. spiritus, female, from Alturas de Banao, Sancti Spiritus Province; G, T. cf. morenoi, male, from Jobo Rosado, Villa Clara Province; H, T. wrighti, from Altiplanicie de El Toldo, Humboldt National Park, Holguín Province. Photos: L. M. Díaz. 



 Luis M. Díaz and Antonio Cádiz. 2020. A New Species of Tropidophis (Squamata: Tropidophiidae) and Molecular Phylogeny of the Cuban Radiation of the Genus [Una nueva especie de Tropidophis (Squamata: Tropidophiidae) y filogenia molecular de la radiación cubana del género] Novitates Caribaea. 16; 1-19. DOI: 10.33800/nc.vi16.222 

Resumen: Cuba tiene la mayor diversidad de serpientes del género Tropidophis, lo cual representa 53 % de todas las especies conocidas. Tropidophis steinleini sp. nov. es descrita de la región oriental de Cuba, lo cual eleva a 17 el número de especies en este archipiélago. La nueva especie está más cercanamente emparentada con T. wrighti, T. spiritus y T. morenoi. Se discuten las relaciones filogenéticas de la nueva especie y otras del género en Cuba, sobre la base de datos moleculares, y se clasifican en tres grupos de acuerdo con la topología del árbol obtenido.