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

Dahinten-Bailey, Hellen, Serrano, Marcelo J., Alonso-Ascencio, Margarita, Cruz-Font, Jose J., Rosito-Prado, Isabella, Ruiz-Villanueva, Kennedy J. A., Vásquez-Almazan, Carlos & Ariano-Sánchez, Daniel, 2021, A new species of Bolitoglossa (Caudata: Plethodontidae) of the Bolitoglossa franklini group from an isolated cloud forest in northern Guatemala, Zootaxa 4966 (2), pp. 202-214 : 205-209

Bolitoglossa qeqom sp. nov.

Fig. 1 A–F , Tables 2 & 3

Holotype. Adult male, UVG-A7015, collected on 4 June 2018 by Kennedy Ruiz-Villanueva in Pamac II natural reserve, Cerro Guachmalén (15.411282 N, - 90.602701 W; 1,862 m elevation), San Cristobal Verapaz, Alta Verapaz, Guatemala. The individual was found active at night crawling above the leave of an understory palm ( Chamaedorea sp. ).

Paratype. Adult female, UVG-A7016, collected on 2 January 2019 by Marcelo Serrano and José Cruz-Font within Pamac II natural reserve (15.409986 N, - 90.605156W; 1,947 m elevation), Cerro Guachmalén , San Cristobal Verapaz, Alta Verapaz, Guatemala. The individual was found active at night climbing on a tree fern ( Cyathea sp. ) .

Additional topotypes. A series of eight individuals ( UTADC 9633–9640 ), collected on 15 August 2020 by Isabella Rosito-Prado, Hellen Dahinten-Bailey, José Cruz-Font, and Marcelo Serrano ( Figs. 2 & 3 , Table 3 ). All individuals were found active at night, on understory fern leaves and some were coming out from the debris and rotten trunks at the type locality .

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 ).

9640) of Bolitoglossa qeqom .

Coloration in life. The color description is based on high-resolution photographs taken of specimens. The ground color of the dorsal surface of the head, trunk, and tail was a dark uniform black tone. When exposed to direct light, the coloration seemed more purplish black-toned, as uniform as previously described. The patch around the nostrils had a pinkish coloration. The upper surfaces of forelimbs and hind limbs presented the same dark purplishblack color, except that under direct light there were pinkish colored areas specifically in the elbows and knees. The hands and feet were a pale translucent dark gray, being almost translucent at the fingertips and darker in the interdigital webbing. The lateral surfaces of the head, body, and tail had this same uniform dark black coloration. The iris was a dark brown with some darker spots. The ventrolateral surface of the head, the ventral surface of the body, and limbs were lighter grayish black. Numerous very fine circular brown and grayish chromatophores were evident in all the trunk, base skin of limbs to insertion of limbs and the head. The chromatophores were more condensed in the gular region making it notably paler than the rest of the ventral surfaces. The ventral surface appearance of the tail is the same as the ventral surface of the trunk.

Description of the holotype. A medium sized male (SVL= 49.9mm); TL 42.7, AG 28.9, FLL 13.9, HLL 12.4, SGF 13.1, PECW 8.1, HWD 6.5, FW 7.6, LiiiF 7.8, LiiiT 7.8, LvT 6.6, HW 10.3, DBE 2.6, EN 2.4, DN 3.6. The head was broad (HW/SVL = 0.21) with a large and bulging mental gland (LMG= 4.47mm). Maxillary teeth numerous (28 on the left side and 25 on the right side), 3 premaxillary teeth (enlarged), 10 right and 8 left vomerine teeth. Premaxillary teeth anterior to the line of maxillary teeth, and the vomerine teeth extending in a row past the outer edge of internal nares. Limbs relatively long with adpressed limbs separated only by one costal fold. Tail relatively long, with a TL/SVL ratio of 0.86. Webbing reduced, digit III with the first two phalanges free of webbing on hands and with the first phalange free of webbing on feet. Phalangeal formulae are 1-2-3-2 for hands and 1-2-3-3-2 for feet. The tips of the toes are broad and blunt.

Color after preservation. Dorsal surface of body, head, tail, and limbs, and lateral surface of body and tail, uniform black purplish. The upper surface of the feet is light brown. Ventral surface of body black-purplish with some light grey at the insertion of forelimbs, pectoral area, and mental gland. Gular region light black purplish with a faint band of light grey extending across gular region anterior to gular fold, the chromatophores are prominent with light brown coloration. The underside of the tail is black purplish, with a white line at the center. The underside of limbs, hands, and feet are light grey.

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.

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.

Figures

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.

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 3. Dorsal view of left hands of Bolitoglossa qeqom topotypes (UTADC 9633–9640). Identification letters correspond to the codes shown in Table 3.

FIGURE 4. Mitochondrial gene tree from Maximum Likelihood analysis of 16S and cytb genes (concatenated sequence of 1078bp) from several salamander species including Bolitoglossa qeqom. Branch lengths are proportional to substitutions. Bootstrap (ML) proportions (%) from RAxML analysis are given outside parentheses and posterior probabilities from MrBayes analysis are inside parentheses.

FIGURE 5. Non-metric multidimensional scaling (NMDS) plots detailing the differences between Bolitoglossa franklini, B. lincolni, B. meliana, B. qeqom, and B. tenebrosa based on morphological measurements. Measurements of the holotype (UVG- A7015), paratype (UVG-A7016), and topotypes (UTADC 9633–9640) are included in the analysis for B. qeqom. Measurements of B. tenebrosa correspond to specimen USAC 2114.

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), B. qeqom (red triangle), and B. tenebrosa (black triangles).