Caudals and Calyces: The Curious Case of a Consumed Chiapan Colubroid
A new genus and species of colubroid snake is described from the isolated highlands of western Chiapas. This enigmatic little snake possesses a unique suite of characters that defies placing it in any known genus and clearly distinguishes it from all known genera. Several of the most unusual features include subcaudals undivided throughout the length of the tail and a simple hemipenis completely adorned with calyces and having a sulcus spermaticus that remains unbifurcated until the apical portion of the organ. Neither of these characteristics is known for any other colubroid of the Western Hemisphere. Consideration of morphology places the new snake in the Dipsadidae and suggests that Adelphicos, Atractus, Geophis, and Chapinophis are among its closest relatives. Se describe un nuevo género y especie de serpiente colubrina de las montañas aisladas del oeste de Chiapas. Esta enigmática y pequeña serpiente posee un conjunto único de caracteres que impide su asignación a cualquier otro género y claramente la distingue de cualquier género conocido. Varios de las características inusuales incluyen subcaudales no divididas a lo largo de toda la cola y un hemipene simple, completamente cubierto de cálices, y con un surco espermático que permanece no bifurcado hasta el ápice del órgano. Ninguna de estas características es conocida de cualquier colúbrido en el hemisferio occidental. Examen de morfología sugiere que la nueva serpiente pertenece a la familia Dipsadidae y su afinidad esta con Adelphicos, Atractus, Geophis, y Chapinophis.Abstract
Resumen
Cenaspis aenigma (holotype, UTA R-10544, 258 mm total length), drawing reconstructing species in life.
Cenaspis aenigma (holotype, UTA R-10544, 258 mm total length), dorsal (A) and ventral (B) aspects of preserved specimen.
Cenaspis aenigma (holotype, UTA R-10544), dorsal (A), lateral (B), and ventral (C) aspects of head of preserved specimen.
Cenaspis aenigma (holotype, UTA R-10544), volume rendering of dorsal (A), lateral (B), and ventral (C) aspects of skull.
Comparison between segmented skulls of Cenaspis aenigma (UTA R-10544) (A–C) and Adelphicos quadrivirigatus sargii (UTA R-22680) (D–F). Dorsal (A and D), lateral (B and E), and ventral (C and F) aspects; quadrate shown in red, palatomaxillary arch in yellow, mandible in green, and cranium in blue. The quadrate of the C. aenigma holotype was digested on the left side, so the right one is shown (although somewhat digested).
Comparison between segmented bones of Cenaspis aenigma (UTA R-10544) (A–C) and Adelphicos quadrivirigatus sargii (UTA R-22680) (D–F). Palatomaxillary arch (A and D; yellow), mandible (B and E; green), and quadrate (C and F; red). Left palatomaxillary arches shown in dorsal, lateral, medial, and, ventral views (top to bottom); left mandibles shown in dorsal, medial, lateral, and ventral views (top to bottom); right quadrate shown for C. aenigma (C) in lateral (left) and medial (right) views, and left quadrate for A. quadrivirigatus sargii (F) in medial (left) and lateral (right) views.
Selected hemipenes of Nuclear Central American snakes. (A) Adelphicos latifasciatus from Oaxaca, UTA R-12246 (left hemipenis, 204 mm snout–vent length [SVL], 54 mm tail length); (B) Cenaspis aenigma holotype from Chiapas, UTA R-10544 (left hemipenis, 222 mm SVL, 36 mm tail length); (C) Cryophis hallbergi from Oaxaca, UTA R-12272 (left hemipenis, 478 mm SVL, 137 mm tail length); (D) Geophis rhodogaster from Guatemala, UTA R-28349 (right hemipenis, 223 mm SVL, 59 mm tail length). Sulcate (left) and asulcate (right) views shown. Note that, except for the hemipenis of C. aenigma, all other organs are spinous and show a well differentiated capitulum, slightly bilobed in Geophis rhodogaster.
Contributor Notes
ZooBank ID: lsid:zoobank.org:pub:981A3DDB-53F9-49D2-B3CD-874A1CEF84C0
