Nototriton oreadorum, Townsend, Josiah H., 2016

Townsend, Josiah H., 2016, Taxonomic revision of the moss salamander Nototriton barbouri (Schmidt) (Caudata: Plethodontidae), with description of two new species from the Cordillera Nombre de Dios, Honduras, Zootaxa 4196 (4), pp. 511-528 : 523-525

Nototriton oreadorum sp. nov.

Pico Bonito Moss Salamander Figure 6 B

Nototriton barbouri: McCranie (1996: 28) ,

Nototriton barbouri (in part): McCranie & Wilson (2002: 143), McCranie & Castañeda (2005: 7; 2007: 108). Nototriton sp. (in part): Townsend et al. (2010: 3).

Nototriton cf. barbouri: Köhler (2011: 78) .

Nototriton sp. A.: Townsend et al. (2011a: 277), Rafaëlli (2013: 368), Townsend et al. (2013: 360). Nototriton (Bryotriton) barbouri (in part): Dubois & Raffaëlli (2012: 141), Rafaëlli (2013: 368).

Holotype. USNM 497552 , an adult female from the south slope of Cerro Búfalo (15.66°N, 86.79°W), 1,540 m elevation, Parque Nacional Pico Bonito, Departamento de Atlántida, Honduras; collected 30 May 1996 by S. Gotte and J.R. McCranie; original field number LDW 10 724; GenBank accession number AF199137 (cyt b).

Paratype. USNM 339712 , an adult female from Quebrada de Oro (15.64°N, 86.80°W), 1,210 m elevation, Parque Nacional Pico Bonito , Departamento de Atlántida, Honduras; GenBank accession numbers AF199201 (16S) , AF199136 (cyt b).

Diagnosis. A member of the genus Nototriton diagnosed by possessing 13 costal grooves (>16 costal grooves in Oedipina ), the presence of a sublingual fold and hands and feet longer than broad (sublingual fold absent and hands and feet broader than long in Bolitoglossa ), and small nares (NL/SVL 0.006–0.009; NL/SVL 0.017–0.029 in Cryptotriton and Dendrotriton ). Phylogenetic analysis supports inclusion of N. oreadorum in the subgenus Bryotriton, and is recovered as a member of the northern clade with N. brodiei , N. nelsoni , and N. stuarti ( Fig. 1 ). From the other species of the northern clade of Bryotriton, N. nelsoni can be distinguished from N. brodiei in having a relatively shorter tail (TL/SVL 0.117–0.122, versus 1.420–1.440 in N. brodiei ), relatively longer front limbs (FLL/SVL 0.158–0.178, versus 0.148–0.151 in N. brodiei ), relatively shorter hind limbs (HLL/SVL 0.190– 0.222, versus 0.166–0.180 in N. brodiei ), and fewer maxillary teeth (47–52, versus 60–62 in N. brodiei ); from N. nelsoni in having a relatively shorter and narrower head (HL/SVL 0.178–0.182 and HW/SVL 0.117–0.122, versus 0.185–0.226 and 0.127–0.142 in N. nelsoni ), relatively shorter front limbs (FLL/SVL 0.158–0.178, versus 0.173– 0.198 in N. nelsoni ), and a higher average number of costal grooves between adpressed limbs (6.0 [± 0.7], versus 4.9 [±1.4] in N. nelsoni ); and from N. stuarti by having a relatively narrower head (HW/SVL 0.117–0.122, versus 0.138 in N. stuarti ), shorter tail (TL/SVL 1.111–1.169, versus 1.264 in N. stuarti ), longer hind limbs (0.190–0.222, versus 0.178 in N. stuarti ), smaller nares (NL/SVL 0.006–0.009, versus 0.012 in N. stuarti ), and more maxillary teeth (47–52, versus 36 in N. stuarti ).

From the remaining species of Bryotriton, N. oreadorum can be differentiated from N. barbouri in having relatively broader hind feet (HFW/SVL 0.056–0.057, versus 0.034–0.052 in N. barbouri ); from N. lignicola in having relatively broader hind feet (HFW/SVL 0.056–0.057, versus 0.035–0.046 in N. lignicola ); from N. limnospectator in having a higher average number of costal grooves between adpressed limbs (6.0 [± 0.7], versus 4.4 [±0.8] in N. limnospectator ); from N. mime in having a relatively longer and broader head (HL/SVL 0.178– 0.182 and HW/SVL 0.117–0.122, versus 0.182–0.201 and 0.121–0.138 in N. mime ), a relatively longer tail (TL/ SVL 1.111–1.169, versus 0.698–1.117 in N. mime ), relatively shorter limbs (FLL/SVL 0.158–0.178 and HLL/SVL 0.190–0.222, versus 0.195–0.246 and 0.224–0.254 for N. mime ), more maxillary teeth (47–52, versus 27–46 in N. mime ), and a higher average number of costal grooves between adpressed limbs (6.0 [± 0.7], versus 4.8 [±0.4] in N. mime ); and from N. picucha in having a relatively shorter and narrower head (HL/SVL 0.178–0.182 and HW/SVL 0.127–0.142, versus 0.197–0.198 and 0.140–0.148 in N. picucha ), shorter limbs (FLL/SVL 0.158–0.178 and HLL/ SVL 0.190–0.222, versus 0.195–0.246 and 0.224–0.254 for N. picucha ), more maxillary and vomerine teeth (47– 52 maxillary teeth and 20–22 vomerine teeth, versus 41 maxillary teeth and 16–19 vomerine teeth for N. picucha ), and a higher average number of costal grooves between adpressed limbs (6.0 [± 0.7], versus 4.0 [±0.7] in N. picucha ). One species of Bryotriton, N. tomamorum , is unique among members of the subgenus in having syndactylous feet (well-differentiated digits in N. oreadorum ) and large nares (NL/SVL 0.018, versus 0.006–0.009 in N. oreadorum ). Nototriton oreadorum can be distinguished from N. saslaya , the only species of the subgenus Nototriton found in the Chortís Highlands, by having more maxillary and vomerine teeth (47–52 maxillary teeth and 20–22 vomerine teeth, versus 17–22 maxillary teeth and 3–11 vomerine teeth in N. saslaya ).

The four species of the northern clade of Bryotriton are all allopatric, and are further differentiated from all other species of Nototriton in the Chortís Highlands by model-corrected genetic distances ( Table 2 ), being 1.5% (16S) and 6% (cyt b) divergent from its closest relative, N. brodiei , and 2.3% (16S) and 5.4–5.7% (cyt b) divergent from samples from N. nelsoni , the species with the most geographically proximate population.

Description of holotype. An adult female (SVL = 33.7 mm, total length = 73.1 mm) with a slender body and reduced limbs. The head is slightly rounded and slightly broader than the body; nostrils are relatively small (NL/ SVL=0.009), and the snout is rounded and of moderate length. Shallow nasolabial grooves are present, with nasolabial protuberances also apparent but not pronounced. The eyes are relatively large and protuberant. There are 47 maxillary teeth, 4 slightly enlarged premaxillary teeth in continuous line with the maxillaries, and 22 vomerine teeth in two well-defined arches. The limbs are short (CLL/SVL=0.37), with approximately five costal grooves between the adpressed limbs. The hands and feet are narrow with well-defined digits that bear subdigital pads. The relative length of the digits is I<IV<II<III on the hands and I<V<II<IV<III on the feet, and the tail is longer than the body (TL/SVL=1.169).

Measurements of holotype (in mm). SL 33.7; AG 19.5; TW 4.9; HL 6.0; HW 4.1; TL 39.4; HLL 6.4; FLL 6.0; CLL 12.4; FFW 1.0; HFW 1.9; NL 0.3; eyelid length 1.7; eye width 1.2; interorbital distance 1.3; anterior rim of orbit to snout 1.5; distance separating internal margins of nares 1.1; distance separating external margins of nares 1.6.

Coloration. Color in life of the female paratype (USNM 339712) as described by McCranie & Wilson (2002: 144) is as follows (color names follow Smithe 1975 –1981): dorsal surface of body Mars Brown (223A), all lateral surfaces Mars Brown (223A) with silver flecks; dorsal surface of tail Verona Brown (223B); ventral and subcaudal surfaces Raw Unber (223) with pale gold flecking.

Osteology. Based on examination of digital radiographs for the holotype ( Fig. 6 B), Nototriton oreadorum is a typical member of the genus possessing a single cervical vertebra, 14 trunk vertebrae (13 of which bear ribs), and 2 caudosacral vertebrae; a partially fused skull roof formed through contact of the frontal and parietal bones, with the anterior portion of the frontals unfused and creating a narrow suture; frontal processes of premaxilla fused at point of origin and separate immediately dorsoposterior to origin; preorbital vomerine processes well-developed into a pair of symmetrical elongate arches, each bearing a single row of numerous teeth, extending beyond the outer margins of the choanae; columella absent; phalangeal formulae 1-2-3-2 and 1-2-3-3-2; penultimate phalanges reduced, equaled or exceeded in length by terminal phalanges on digits II, III, and IV of the forelimbs and digits II, III, IV, and V of hind limbs; terminal phalanges slightly expanded at distal tips, expansion more pronounced in digit III of forelimbs and digit III of the hindlimbs; mesopodial elements not mineralized. Examination of radiographs of the paratype (USNM 339712) generally agreed with those of the holotype, with the paratype having less complete fusion of the frontal and parietal elements than the holotype.

Etymology. The specific epithet means “belonging to the mountain nymphs”, referring to the Oreads of Greek mythology. The Oreads were female nature deities associated with mountains and valleys, alluding to the steep and challenging terrain at the type locality.

Geographic and ecological distribution. This species is known only from the vicinity of Cerro Búfalo in Parque Nacional Pico Bonito, Honduras, 1,210–1,540 m elevation. The distribution falls within the Lower Montane Wet Forest formation ( Holdridge 1967), with the habitat at the type locality classified as Broadleaf Cloud Forest ( Townsend 2014).

Natural history. The holotype of N. oreadorum was found during the day under a log on a relatively steep forested slope on the south-southeastern face of Cerro Búfalo ( McCranie & Townsend 2011). This species occurs in sympatry with another endemic semi-fossorial salamander, Oedipina petiola , a species known only from a single specimen collected from under another log located uphill from the type locality ( McCranie & Townsend 2011).

Figures

FIGURE 1. Bayesian phylogram of the genus Nototriton showing phylogenetic relationships based on analysis of a concatenated and partitioned dataset of fragments of the mitochondrial genes 16 S, cyt b, and COI, with Bayesian posterior probabilities and bootstrap support values from a complimentary maximum likelihood analysis shown above supported branches.

FIGURE 6. Digital radiographs of the holotypes of Nototriton nelsoni (A; USNM 578300) and N. oreadorum (B; USNM 497552).