Sarcohyla floresi Kaplan & Heimes & Aguilar 2020, sp. nov.

Sarcohyla floresi sp. nov.

Holotype. UMMZ 239718 (original field number MK 774), an adult female from Sierra del Alquitran, 2128 m (17° 26’ N 99° 31’ W), south of Chilpancingo and west of Mazatlán, Guerrero, Mexico, obtained by Rafael Aguilar in March, 2003.

Paratypes. UMMZ 239798, El Salado, east of Mazatlán, Guerrero, UMMZ 239739-43, on the Atoyac de Alvarez to Puerto del Gallo road, Guerrero, UMMZ 239744, near Carrizal de Bravo, Guerrero, all juveniles collected by Moises Kaplan, Peter Heimes, Rafael Aguilar, and Juan Manuel Romero Aguilar from March 1-5, 2004; KU 140424–26 (original field numbers MN 4528−30), 5.6 km (by road) NE Yerbabuena, Guerrero, juveniles, collected on 1969; LACM 92416 7−9 mi W Mazatlán, Guerrero, collected by B. Borman and T. Papenfuss on August 16, 1973; IBH 138072, 9 km E El Salitre on road to Nanchititla, collected by G. Parra-Olea and M. Garcia-Paris on April 19, 2002; and MZFC 30710−11 Rio Frio, Municipality of Coyuca de Catalán, collected by Elizabeth Beltrán- Sánchez on December 12, 2007.

Diagnosis. A large, robust tree frog with long fingers, vestigial webbing on fingers, stream-dwelling tadpoles with labial tooth row formulae (hereafter LTRF) 2(2)/3, oral disc of tadpoles completely surrounded by marginal papillae and a single row of large submarginal papillae between the anterior and posterior tooth rows and marginal papillae. The phylogenetic analysis of Zarza et al. (2018) showed that S. floresi is nested within Sarcohyla.

S. floresi can be distinguished from all known species of Sarcohyla, except S. pentheter, by having adults with a bold broad chocolate-brown band (hereafter dorsolateral band) edged by a pale line on side of head from edge of upper lip through nostril and eye, along supratympanic fold and sides of body and similar bands along inner and outer edges of limbs (Figs 1, 2A, 2B).

S. floresi differs from S. pentheter (condition in parentheses) by having dorsum of body, head, and limbs peppered with small dark flecks (dark flecks absent); dark bands on posterior surfaces of limbs wide, peppered with small pale spots (narrow, pale spot absent) (Figs. 1, 2A, 2B, 2E, 2F); dorsolateral bands on head converging medially and extending, as a single broad band, from nostril to upper lip (dorsolateral bands on head reach upper lip independently from one another) (Figs. 2C and 2D); dorsolateral band wide, with jagged dorsal edge, breaking ventrally and posteriorly into long sinusoidal interconnected blotches that cover most of flank (dorsolateral band narrow, lobate on both edges, covering little of flank’s surface, keeping its integrity except for few small disconnected spots nearby) (Figs. 2A and 2B); thin dark band along upper lip not broadening below anterior edge of eye (broadening) (Fig. 1; see Adler 1965 plate I, figs. D and E); thin dark band along lower lip widens at angle of jaw, breaking into irregular dark spots along edge of throat (band narrow at angle of jaw, throat spots absent) (Fig. 1); dark irregular blotches present on body dorsally to arm insertion (blotches absent) (Fig. 1); dorsal fin of tadpole with scattered light blotches in life (dorsal fin with dense pattern of dark blotches [Kohler et al. 2016, Fig. 9e]).

Description of the holotype (measurements in millimeters). snout–vent length (SVL) 55.9; head length (HL) 17.9; head width (HW) 21.2; eye diameter (ED) 6.0; tympanum diameter (TD) 3.3; interorbital distance 4.5; eye to nostril distance 4.3; eye to tip of snout distance 8.2; eye to tympanum distance 2.7; diameter of terminal disc of Finger III 3.7; thigh length 26.9; shank length 29.3; foot length 25.8; inner metatarsal tubercle longest diameter 2.9; outer metatarsal tubercle diameter 0.6; diameter of terminal disc of Toe IV 3.1.

Body robust; head slightly wider than long (HL/HW 0.84); snout long, round in dorsal, ventral and lateral views, extending well beyond jaw in ventral view; canthus rostralis round, barely distinct; loreal region slightly concave; rostral keel absent; eyes small (ED 34 % of HL; tympanum large (TD 55% ED), concealed dorsally by supratympanic fold and ventroposteriorly by skin; tympanic ring distinct, slightly more elevated anteriorly than posteriorly.

Fingers long; webbing marginal between Fingers I and II; webbing formulae II2 -- 3 -- III3 + - 21/2 -IV; distal subarticular tubercles of Fingers II and III large, conical; distal subarticular tubercle of Finger IV large, round, not bifid; proximal subarticular tubercles of Fingers III and IV small, conical; supernumerary tubercles round, small; terminal disc of Fingers II, III, and IV elliptical, large (diameter of terminal disc of Finger III 1.1 times diameter of tympanum); terminal disc of Finger I round, slightly larger than the rest of finger, smaller than discs of other fingers; webbing formulae of foot I1-2II1- 21/2 -III 11/2 -3 + -IV3 + -1V; terminal discs of toes nearly round, less expanded than discs of fingers (diameter of terminal disc of Toe III 84% of diameter of terminal disc of Finger III); inner metatarsal tubercle ovoid; outer metatarsal tubercle present, slightly larger than supernumerary tubercles of foot.

Skin of dorsum of body, head, and limbs smooth; skin of flanks smooth; throat and chest slightly tuberculate; belly and medial part of thighs shagreened; thoracic fold groove-like, complete (not interrupted medially); axillary membrane absent; venter of arms slightly tuberculate; ulnar tubercles distinct, independent, nearly flat, forming row; tarsal fold ridge-like, tuberculate, long, nearly reaching heel; anal opening at midlevel of thighs; anal sheath split by medial, deep, longitudinal groove and several shallow lateral grooves; anal sheath slightly longer medially than laterally; perianal tubercles slightly larger and more prominent than other tubercles of posterior surface of thighs; tongue wide, cordiform, slightly notched posteriorly; vomerine patches ovoid, traverse, elevated, each with 5 to 7 small vomerine teeth, located between two small ovoid choanae.

Lateral surfaces of dorsum peppered with small dark flecks (Figs. 1, 2A, 2B, 2E, 2F). Bold broad dark dorsolateral bands edged dorsally by pale line extend from snout through nostrils and eyes, along supratympanic folds and flank of body. Dorsolateral bands on head converge medially and extend, as a single broad band, from an area below nostrils to upper lip. Side of head posterior to eye, including tympanum, very dark, indistinguishable from dorsolateral band. Upper and lower lips bordered by narrow dark bands; band on lower lip widens at angle of jaw, breaking into irregular dark spots that extend along edge of throat. Dorsolateral bands extend posterior to arm insertion along flank of body, breaking ventrally and posteriorly into long sinusoidal mostly interconnected blotches that cover most of surface of flank (Figs. 2A and 2B). Large, irregular dark blotches present on body dorsally to arm insertion (Fig. 1). Dorsum of limbs sparsely peppered with small dark flecks. Posterior surfaces of limbs covered by wide medium dark bands peppered with small pale spots (Figs 1, 2A, 2B, 2E, 2F). Dorsal edges of bands on thighs jagged. Anterior surfaces of thighs and arms covered with light reticulations and dark band, respectively. Ventrum of body and head immaculate except for dark spots on the periphery of throat (Fig. 1).

In preservative, dorsum of body, head, and limbs pale grayish brown with soft reddish hue; dorsum of Fingers I and II and terminal discs of toes dull yellow; ventrum of body, head, and limbs yellow, slightly paler on belly; ground color of flank pale cream; dorsolateral bands on head, body, and limbs dark chocolate-brown; band on snout and head posterior to eye, including tympanum, dark chocolate-brown; row of flat ulnar tubercles whitish.

In life (Fig.1) dorsum of body and head beige; dorsum of limbs and loreal region of head reddish dark beige; tips of fingers and toes yellowish brown; dorsolateral band on head, body, and limbs as well as blotches on flank, throat, and chest dark chocolate- brown; hidden surfaces and ventrum of body and limbs pale yellow; flank of body dorsal to arm insertion dark yellow; row of ulnar tubercles pale yellow; iris copper.

Natural history. The holotype was found inside a fissure of a large boulder on a mountain crest far from a body of water. The type locality consists of dry deciduous forest characteristic of the Pacific slopes of the Sierra Madre del Sur of Guerrero (Rzedowski, 1978). All tadpoles were found during the day in pools formed in streams.

Variation. Adults LACM 92416, KU 140424 -26, and IBH 13807 have snout truncate in dorsal view and IBH 13807 has band on upper lip broadening below eye.

All juveniles (UMMZ 239798, 239739–43, 239744) (SVL 35.3–41.9) have dorsolateral bands partially fused to one another at the midline; loreal regions very dark, almost indistinguishable from dorsolateral bands; dorsolateral band on body short, breaking anterior to arm insertion into large, mostly independent, round or elongated spots that cover most of surface of pale to whitish flank; dark, sinuous, and mostly interconnected spots forming reticulated pattern over posterior surfaces of thighs; flank cream-yellow, hidden surfaces yellow-orange, anal sheath reaching ventral level of thighs, and thoracic grooves medially interrupted. Juveniles can lack dark flecks on dorsum of body and limbs (UMMZ 239743), have band of upper lip broaden below eye (UMMZ 239798), and flank surface partially covered by dark spots (UMMZ 239744).

Description of the tadpole (UMMZ 23992) (Stage 36) (measurements in millimeters). Total length 55.8; body length 17.4; tail length 38.4; height of caudal musculature (at base of tail) 6.4; width of caudal musculature (at base of tail) 5.4; tail maximum height 9.5; maximum height of dorsal fin 2.7; maximum height of ventral fin 2.7; body width 9.8; body height 8.3; eye diameter 2.2; interorbital distance 3.6; nostril length 5.0; snout to opening of spiracle distance 11.7; oral disc diameter (traverse) 4.9.

Body ovoid (Fig. 4A), elongate in dorsal view, widest posterior to eyes at level of spiracle, slightly wider than high, not depressed in lateral view; eyes moderate in size, round, situated dorsolaterally; nostril oval, directed anterolaterally, situated closer to eye than to tip of snout; spiracle sinistral, forming round aperture, situated on midline, slightly closer to tip of snout than to posterior end of body; vent tube dextral; caudal musculature robust, highest at base, gradually tapering to pointed tip; caudal fin tip rounded; dorsal and ventral fins of nearly equal heights throughout their lengths.

Oral disc large (Fig. 4B), not emarginated, completely bordered by marginal papillae; marginal papillae single, short, and densely packed at anterior and posterior ends of oral disc, double, long, and flexible at lateral, anterolateral, and posterolateral parts of oral disc; one complete row of large submarginal papillae between anterior tooth row and submarginal papillae and one row of small submarginal papillae between posterior tooth row and marginal papillae; 15 to 20 small submarginal papillae clump laterally to anterior and posterior tooth rows and slightly anterolaterally and posterolaterally to them; LTRF 2(2)/3; A1 slightly longer than A2; P2 and P3 as long as A2, slightly longer than P1; relative lengths of labial teeth A1, A2, P1> P2> P3. Lower sheath, well cornified; upper sheath poorly cornified except on lateral extensions; serration on upper sheath larger and better defined than that of lower sheath.

In preservative, dorsum of body yellowish brown, belly dark bluish gray; tail musculature beige; blotches on tail musculature and fins light brown, small, rounded, denser on posterior 2/3 of tail; anterior 1/5 of tail musculature unpigmented in dorsal view; subdermal white blotches on sinistral flank of body; scattered white subdermal pigment on other parts of ventrum of body.

In UMMZ 239925, upper sheath of oral disc very small, cornified only medially and along lateral extensions, not serrated.

Etymology. This species is named after Oscar Flores Villela, a researcher and teacher at the Museo de Zoologia, Facultad de Ciencias, Universidad Nacional Autonoma de México, to recognize his life-long commitment to the science and conservation of amphibians and reptiles in México.