Thursday, May 6, 2021

[Herpetology • 2021] Bolitoglossa qeqom • A New Species of Bolitoglossa (Caudata: Plethodontidae) of the Bolitoglossa franklini Group from An Isolated Cloud Forest in northern Guatemala

Bolitoglossa qeqom 
Dahinten-Bailey, Serrano, Alonso-Ascencio, Cruz-Font, Rosito-Prado, Ruiz-Villanueva, Vásquez-Almazán & Ariano-Sánchez, 2021

We describe Bolitoglossa qeqom sp. nov. from an isolated cloud forest in Cerro Guachmalén, Alta Verapaz, Guatemala, based on multiple lines of evidence (morphological, molecular, and biogeographic data). This region comprises a mountain ridge without previous herpetological surveys. The new species is a large salamander with uniform purplish-black coloration and is distinguished by having relatively long legs with only one costal groove between adpressed limbs, numerous maxillary teeth, few vomerine teeth, only one phalange free of webbing in digit III of feet, and a relatively short tail. It is geographically closest to its sister clade of B. lincolni + B. franklini and the xeric Chixoy river canyon appears to be the major biogeographic barrier that isolated the new taxon. The cloud forest inhabited by this species has undergone severe habitat destruction in the region and land conservation actions are urgent.

Keywords: Amphibia, Bolitoglossa franklini species group, 16S, cytb, restrict endemism, Chixoy River

FIGURE 1. General view in life (A), after preservation (B), left hand (C), left feet (D), lateral view of head (E), maxillary and premaxillary teeth (F), and landscape view of the type locality (G) of the holotype of Bolitoglossa qeqom (UVG-A7015), SVL 49.9 mm.
Drawings by M. Alonso-Ascencio.

Bolitoglossa qeqom sp. nov. 
Diagnosis. This is a large uniformly purplish-black colored Bolitoglossa of the franklini species group (Stuart 1943), subgenus Magnadigita (Taylor 1944). We have assigned it to Bolitoglossa because it lacks a sublingual fold and to Magnadigita based on its reduced interdigital webbing, well-defined digits with broad tips, and its phylogenetic relationships according to molecular data. Molecular data shows that B. qeqom is the sister taxon of B. lincolni + B. franklini with high support (bootstrap proportion [BS] = 91, posterior probability [PP] = 1) with relatively large genetic distances from other members of this clade (Fig. 4). Bolitoglossa qeqom differs from all other species of the sub-genus by its large adult size except from B. franklini Wake & Lynch 1982, B. lincolni Elias 1984, B. meliana Wake & Lynch 1982, B. omniumsanctorum Campbell et al. 2010 and B. tenebrosa Vásquez-Almazán & Rovito 2014. The new species differs from B. franklini, B. lincolni, B. meliana, B. tenebrosa, and B. tzultacaj Campbell et al. 2010 by having only one phalange free of webbing in digit III of feet and relatively longer legs with only one costal groove between adpressed limbs (Table 2). Differs from B. franklini, B. lincolni, B. meliana, and B. tzultacaj (sub-adult) by having more maxillary + premaxillary teeth, and two phalanges free of webbing in digit III of hand. The new species can be distinguished from B. franklini, B. meliana, and B. tenebrosa by having fewer vomerine teeth, relatively shorter tail, and by having only one phalange free of webbing in digit III of feet. The new taxon can be distinguished from other related species through the combination of several morphometric characteristics as is shown in the NMDS analysis (Fig. 5).

Etymology. The specific epithet is taken from the Poqomchi Mayan language word q’eqom that means dark, in allusion to its uniformly purplish-black coloration and the overwhelming darkness of the nights within the restricted patch of forest where we found this species. The species name is a noun in apposition to the genus name.


FIGURE 2. Lateral view of the head of Bolitoglossa qeqom topotypes (UTADC 9633–40). Identification letters correspond to the codes shown in Table 3.


FIGURE 6. Map of Sierra de los Cuchumatanes, Cerro Guachmalén, Chixoy river canyon, and Sierra de Yalijux, Guatemala, showing the distribution of Bolitoglossa lincolni (white circles), B. meliana (black diamonds), Bolitoglossa qeqom (red triangle), and B. tenebrosa (black triangles).

Distribution and habitat. The species is known only from Cerro Guachmalén, San Cristóbal Verapaz, Alta Verapaz (Fig. 6) at around 1,900 m elevation in a cloud forest. The vegetation is characterized by the presence of the following species: Cojoba arborea, Fabaceae; Quercus spp., Fagaceae; Alfaroa guatemalensis, Juglandaceae; Dendropanax arboreus, Araliaceae; Amphitecna montana, Bignoniaceae; various species of Lauraceae and the recently described Magnolia poqomchi (Serrano et al. 2020), Magnoliaceae. The broadleaf cloud forest in this area is isolated from other montane forests by lower elevations surrounding it, where the habitat is highly fragmented by subsistence maize crops and migratory farming. 

Life history and ecology. Bolitoglossa qeqom seems to be a mainly terrestrial salamander as most individuals (including the holotype and paratype) were found in very low understory vegetation or coming out from the debris and loose bark of fallen logs. This species seems to be restricted to a very small area at the type locality where a water spring emerges, as we were unable to find other specimens of this species in the rest of Cerro Guachmalén after several field trips. This salamander is relatively abundant at this site, with usually 10–15 salamanders being found on every trip of different age classes and sexes in this tiny forest patch (~ 5 ha). A large gravid female was found during August at the site. 

Hellen Dahinten-Bailey, Marcelo J. Serrano, Margarita Alonso-Ascencio, Jose J. Cruz-Font, Isabella Rosito-Prado, Kennedy J. A. Ruiz-Villanueva, Carlos R. Vásquez-Almazán & Daniel Ariano-Sánchez. 2021. A New Species of Bolitoglossa (Caudata: Plethodontidae) of the Bolitoglossa franklini Group from An Isolated Cloud Forest in northern Guatemala. Zootaxa. 4966(2); 202–214.  DOI: 10.11646/zootaxa.4966.2.7

Estudiantes de biología de Guatemala descubren nueva especie de salamandra en bosque de Alta Verapaz
El nombre científico de la salamandra es “Bolitoglossa qeqom”, proviene del vocablo q’eqom del idioma maya poqomchi’ y significa oscuro, en alusión a su color negro azulado profundo y a la oscuridad del bosque prístino donde se encontró esta especie”.