Thursday, January 4, 2024

[Herpetology • 2024] Abronia cunemicaBridging the Gap: A New Species of Arboreal Abronia (Squamata: Anguidae) from the Northern Highlands of Chiapas, Mexico


Abronia cunemica   
 Clause, Luna-Reyes, Mendoza-Velázquez, Nieto-Montes de Oca & Solano-Zavaleta, 2024

 
Abstract
The mountain forests of Middle America are renowned for their endemic biodiversity, and arboreal alligator lizards (genus Abronia) are high-profile vertebrates endemic to this region. In this work, we describe a new species of arboreal Abronia that is known only from the type locality in the Northern Highlands of Chiapas, Mexico. The new species is diagnosed from all other members of the genus Abronia by the following combination of characters: lack of protuberant or spine-like supra-auricular scales, lack of protuberant or casque-like posterolateral head scales, dorsum of head pale yellow with distinct dark markings, 35–39 transverse dorsal scale rows, lateralmost row of ventral scales enlarged relative to adjacent medial row, and dorsum brown with darker crossbands that are sometimes reduced to rows of spots. We provisionally include the new species in the subgenus Lissabronia based on genomic and morphological evidence, but our results also suggest a close relationship to the subgenus Abaculabronia. The new species is geographically separated from the nearest Lissabronia and Abaculabronia species by the lowland Central Depression of Chiapas. Ongoing habitat loss and other factors imperil the new species, leading us to propose its listing under multiple threatened species frameworks. Because the Northern Highlands have poor coverage of protected areas, we briefly comment on the potential of this new species for stimulating conservation in the region.

Color variation in life of type series of Abronia cunemica sp. nov. from Coapilla, Chiapas, Mexico.
(A) Adult male holotype, MZFC-HE 36544, 127 mm snout-to-vent length (SVL); (B) adult female paratype, MZFC-HE 36545, 113 mm SVL; (C) adult female paratype, MZFZ 4514 (AGC 1492), 110 mm SVL; (D) adult female paratype, MZFZ 4513 (AGC 1491), 107 mm SVL; (E) juvenile male paratype, MZFZ 4512 (AGC 1484), 91 mm SVL.
Photographs by Emmanuel Javier-Vázquez.

Abronia cunemica Clause, Luna-Reyes, Mendoza-Velázquez, Nieto-Montes de Oca & Solano-Zavaleta sp. nov.
 
Dragoncito de Coapilla (recommended Spanish common name)
Coapilla Arboreal Alligator Lizard (recommended English common name)

Diagnosis: Abronia cunemica sp. nov. can be distinguished from all recognized congeners, including all species formerly considered members of the genus Mesaspis, by the following combination of characters: (1) lack of protuberant or spine-like supra-auricular scales; (2) lack of protuberant or casque-like posterolateral head scales; (3) dorsum of head pale yellow with distinct dark markings; (4) 35–39 transverse dorsal scale rows; (5) lateralmost row of ventral scales enlarged relative to adjacent medial row; and (6) dorsum brown with dark crossbands, these sometimes reduced to series of dark spots.

Geographic distribution of Abronia cunemica sp. nov. and nearby arboreal congeners in Chiapas and Oaxaca, Mexico. Inset photographs show characteristic differences in adult dorsal head color between A. cunemica sp. nov. (pale yellow, with dark markings distinct) and the closely related A. morenica (pale gray/tan, with dark markings absent or faint). The holotypes (adult males) of both species are shown; photograph of A. cunemica sp. nov. intentionally mirrored horizontally.
 Photographs by Adam G. Clause. Map layers courtesy of Natural Earth (public domain).

Etymology: The species name is a feminine singular adjective in the nominative case derived from Cuñemo (alternative spellings: Kuñømø or Kujnyä’mä), which is the name for Coapilla in the indigenous Zoque language. Coapilla is derived from the Náhuatl words coatl (snake) and apan (river) and means “river of the snakes,” while Cuñemo has been variously translated as agua entre los árboles (“water among the trees” in English) [85], lugar de la gran capital (“place of the new or great capital”) [86], or corona de cerros (“crown of hills”) according to residents of the area. The chosen name, derived from the Zoque language, thus refers to the ejido and municipality which support the only known population of the new species. Our inquiries with residents of Coapilla about this name received universally positive responses. The recommended English pronunciation is “koon-YEM-ih-kuh.”

Habitat of Abronia cunemica sp. nov. near Coapilla, Chiapas, Mexico.
 (A) Live and dead Pinus chiapensis trees in a cattle pasture, (B) intact Pinus-Quercus forest, (C) microhabitat of Quercus spp. trees laden with epiphytes.
 Photographs taken by Adam G. Clause on 19 February 2022 (A) and 14 August 2021 (B–C).

 
Adam G. Clause, Roberto Luna-Reyes, Oscar M. Mendoza-Velázquez, Adrián Nieto-Montes de Oca and Israel Solano-Zavaleta. 2024. Bridging the Gap: A New Species of Arboreal Abronia (Squamata: Anguidae) from the Northern Highlands of Chiapas, Mexico. PLoS ONE. 19(1): e0295230. DOI: 10.1371/journal.pone.0295230