Oedipina petiola, Mccranie, James R. & Townsend, Josiah H., 2011

Mccranie, James R. & Townsend, Josiah H., 2011, Description of a new species of worm salamander (Caudata, Plethodontidae, Oedipina) in the subgenus Oedopinola from the central portion of the Cordillera Nombre de Dios, Honduras, Zootaxa 2990, pp. 59-68 : 62-63

Oedipina petiola sp. nov.

Figures 2–3

Oedipina gephyra . McCranie 1996: 29, García-París & Wake 2000: 45 (part), McCranie & Wilson 2002: 155 (part), McCranie & Castañeda 2005: 7, McCranie 2006b: 7 (part), McCranie & Castañeda 2007: 116 (part), McCranie et al. 2008: 4, Sunyer et al. 2010: 31.

Holotype. USNM 343462, subadult male, from south slope of Cerro Búfalo, 15°39’N, 86°48’W, Parque Nacional Pico Bonito, Cordillera Nombre de Dios, 1580 m elev., Atlántida, Honduras, collected 18 February 1995, by James R. McCranie.

Diagnosis. A moderate-sized (holotype is a subadult male with 42.6 mm SVL; Figure 2 ) member of Oedipina , subgenus Oedopinola. Distinguished from Oedipina (Oedopinola) gephyra and Oedipina (Oedopinola) tomasi by having narrower hind feet with less discrete digits ( Figure 3 ; hind foot width / SVL 0.019 in O. petiola versus 0.024–0.028 in four adult males, 0.021–0.028 in ten adult females, and 0.028 in one subadult O. gephyra and 0.028 in one adult male O. tomasi ; discrete digital groves in O. petiola versus distinct grooves in O. gephyra and O. tomasi ; no transverse grooves at proximal edges of digits in O. petiola versus distinct grooves at proximal edges of digits in O. gephyra and O. tomasi ). Oedipina petiola differs from the other described Honduran species of the subgenus Oedopinola ( O. elongata ) in having narrower hind feet (hind foot width / SVL 0.019 versus 0.032 in one male O. elongata ), in having 34 maxillary teeth (maxillary teeth usually absent in O. elongata ), and in lacking distinct pale markings (distinct pale markings present on top of head and anterior portion of body in O. elongata ). The new species differs from all other Honduran species of Oedipina ( O. ignea , O. kasios , O. leptopoda , O. quadra , O. stuarti , and O. taylori ) by having 17 costal groves (19–21 in those six species). In addition, O. petiola differs in mtDNA from all other members of the genus Oedipina in which that data is known ( Table 1 ), being 4.0–4.2% divergent for 16S and 6.6% divergent for cyt b from its closest known relative, O. gephyra (Table 2).

Description of holotype. Subadult male with SVL of 42.6 mm. Snout truncate in dorsal aspect, bluntly rounded in profile; head width 3.8, SVL / head width 11.2, head width / SVL 0.089; head length 6.9 mm, SVL / head length 6.2; nostrils small, situated near tip of snout; distinct nasolabial groove extending from lower-posterior margin of each nostril to lip; labial protuberances small; canthus rostralis moderately arched; eyes not protuberant, not visible beyond margin of jaw when viewed from below; suborbital groove distinct; postorbital groove shallow, extending posteriorly from eye before turning sharply ventrally to connect with gular fold, another branch proceeding sharply ventrally just posterior to mandible, extending across throat anterior to gular fold; no dermal glands on head or body; mental gland only faintly indicated; 34 maxillary teeth, extending posteriorly to a point two-thirds distance through length of orbit; two enlarged premaxillary teeth, located posterior to lip and in line with maxillary teeth; 20 vomerine teeth, in long, single, arched series, extending beyond outer edge of internal nares; axillarygroin length 26.0 mm; 17 costal grooves (18 trunk vertebrae inferred); tail incomplete, thick, broadly rounded at base, barely constricted at base; tail width 2.4 mm, SVL / tail width 17.8; tail depth 2.6 mm, SVL / tail depth 16.4; postilliac gland not visible; limbs short, 11 costal folds not covered when fore- and hind limbs adpressed along side of body; hind limb length 6.5 mm, SVL / hind limb length 6.6; hind foot width 0.8 mm, SVL / hind foot width 53.3, hind foot width / SVL 0.019; digits I and II and III and IV on forelimbs fused and without indentation in webbing between digits II and III; digits I and II fused on hind limbs, dorsal grooves discrete between digits II–IV and absent at proximal edges of all digits; relative length of digits I<IV<II<III on forelimbs, I<V<II<IV<III on hind limbs; cloacal papillae present.

Color in life: dorsum of body and tail Jet Black (89), that of head and limbs slightly paler black; ventral surface of body slightly paler black than dorsum of body; subcaudal surface Jet Black.

Color in alcohol: dorsum of head and body grayish black, that of tail black, that of limbs brownish gray; ventral surface of head pale brown with black mottling; gular fold pale brown; ventral surface of body grayish black, that of tail black; ventral surfaces of limbs brown; tiny white iridophores present on body, especially laterally.

Habitat and distribution. The single known specimen was under a log during February 1995 in primary broadleaf cloud forest (Lower Montane Wet Forest formation of Holdridge 1967) at 1580 m elevation. Other salamanders found at the same time and locality were representatives of the Nototriton barbouri and Bolitoglossa porrasorum complexes. The single specimen of the Nototriton was also under a log and the Bolitoglossa were common in arboreal situations. The collection site was reached by climbing from the Quebrada de Oro at 950 m elevation along the side of a large landslide. The site is located about 50 m W of the edge of the landslide. A return trip to the type locality for three days during late May 1996 failed to find additional specimens of the Oedipina .

Comment. One anonymous reviewer suggested that the foot morphology of the subadult holotype of the new species might differ from the foot morphology of O. gephyra because the former is known only from a subadult with a SVL of 42.6 mm. Therefore, we compared the foot morphology of O. petiola to a subadult (USNM 343458) of O. gephyra from that species’ type locality. That subadult O. gephyra (SVL 35.7 mm) has a hind foot width / SVL of 0.028 (at the upper level of that ratio for adult O. gephyra ) and better developed digital grooves compared with the larger holotype of O. petiola .

Etymology. The name petiola is from Latin petiolus, meaning diminutive foot, and refers to the narrow feet in the holotype.

Phylogenetic relationships. Both Bayesian and ML analyses ( Figure 4 ) support Oedipina petiola as the sister species to O. gephyra (bootstrap [bs] = 96, posterior probability [pp] = 1.0), forming a clade with their sister taxon O. tomasi (bs = 100, pp = 1.0). Both analyses also recovered clades corresponding to the subgenera Oedipina, Oeditriton , and Oedopinola ( Figure 4 ), and support inclusion of O. petiola and the rest of the O. gephyra group in Oedopinola. Although only a single sample of O. petiola is available, intraspecific variation in its sister species is very low (0.0–0.2% for 16S, 0.0% for cyt b) compared with the interspecific divergence between O. petiola and O. gephyra (4.0–4.2% for 16S, 6.6% for cyt b). Based on sequence divergence (Table 2), O. petiola is well differentiated from the remaining species of the subgenus Oedopinola (5.9–10.1% for 16S, 16.1– 25.3% for cyt b).

Figures

FIGURE 2. Subadult male holotype of Oedipina petiola (USNM 343462; SVL = 42.6 mm) in life.

FIGURE 3. Comparison of foot morphology between the holotype of Oedipina petiola (USNM 343462; SVL = 42.6 mm) and subadult (USNM 343458; SVL = 35.7 mm) and adult (USNM 530585; SVL = 54.1 mm) O. gephyra; A) dorsal (left) and ventral (right) views of right hind foot of O. petiola, B) dorsal (left) and ventral (right) views of right hind foot of a subadult O. gephyra, C) dorsal (left) and ventral (right) views of right hind foot of an adult O. gephyra.

FIGURE 4. Bayesian phylogram based on concatenated and partition 16 S and cyt b dataset, showing phylogenetic hypothesis for the genus Oedipina and its three subgenera and relationships of O. petiola sp. nov. Maximum likelihood bootstrap values and posterior probabilities less than 60 and 0.6 are not shown.