A New Species of Abronia (Squamata: Anguidae) from a Protected Area in Chiapas, Mexico

Bridging the gap: A new species of arboreal Abronia (Squamata: Anguidae) from the Northern Highlands of Chiapas, Mexico

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.

Selva Zoque, Mexico: an important Mesoamerican tropical region for reptile species diversity and conservation

The Selva Zoque region is characterized by a great variety of ecosystems for which there is little information about reptile species diversity and their conservation status. This study is the first assessment of the species richness, composition, and conservation status of reptiles of this region. Additionally, this information is compared with that of seven other tropical regions in northern Mesoamerica. In total, 141 native reptile species belonging to 81 genera and 29 families are recorded for the Selva Zoque region. Sixty species (42% of the total) recorded in Selva Zoque are in high-risk categories according to the Mexican Ministry of the Environment, the highest number for the Mexican regions of Mesoamerica. According to the IUCN, six species are in high-risk categories, seven species are in Data Deficient, and 23 (16%) have not been evaluated yet. According to the Environmental Vulnerability Scores approach, 28 species (20%) are in the high vulnerability category. The Selva Zoque species composition is most similar to Los Tuxtlas and Lacandona regions, and most dissimilar to Sian Ka´an Biosphere Reserve. The reptilian fauna of Selva Zoque has a distinctive composition, with the highest number (11 species) of endemic reptiles in the northern Mesoamerican, and species from two biogeographic provinces: the Gulf of Mexico and the Mexican Pacific Coast. These results indicate that the Selva Zoque is the most diverse region in native reptile species in northern Mesoamerica, highlighting it as extremely important for the conservation of the reptile fauna at local (southern Mexico) and regional levels (northern Mesoamerica).

Phylogenomics of the Mesoamerican alligator-lizard genera Abronia and Mesaspis (Anguidae: Gerrhonotinae) reveals multiple independent clades of arboreal and terrestrial species

Abronia and Mesaspis are two of the five anguid lizard genera in the subfamily Gerrhonotinae. Their members are restricted to Mesoamerica, and most have allopatric distributions. Species of Abronia are primarily arboreal and occur in cloud and seasonally dry pine-oak forests, whereas those of Mesaspis are terrestrial and inhabit mesic microhabitats of montane forests. Recent molecular studies suggest that although these genera together form a monophyletic group, neither genus is monophyletic. Here we performed a phylogenetic study of Abronia and Mesaspis based on the most comprehensive taxonomic sampling of these genera to date and double digest restriction site-associated (ddRADseq) data. Our reconstructed phylogeny differed considerably from all previously published topologies, consistently recovering multiple independent clades of arboreal and terrestrial species and Abronia and Mesaspis as non-monophyletic. Geography, rather than current taxonomy, provides the best explanation of their phylogenetic relationships. Our analyses consistently recovered two main clades, distributed on the highlands of Middle America east and west of the Isthmus of Tehuantepec, respectively, and each composed of subclades of Abronia and Mesaspis. In the former main clade, members of the subgenus Auriculabronia formed the sister taxon to the Mesaspis moreletii complex, whereas the main clade west of the Isthmus was composed of two clades with a subclade of Abronia and another of Mesaspis each (one clade on the Atlantic versant of the main mountain ranges of eastern Mexico and another one on the Sierra Madre del Sur exclusive of its Atlantic versant) and a third clade with species of the subgenera Abronia and Scopaeabronia. We discuss the taxonomic implications of our results for the classification of the examined taxa and list the morphological characters that diagnose the recovered clades. This study highlights the utility of ddRADseq data to reconstruct the evolutionary history of supraspecific vertebrate taxa.