Ptychohyla zoque, Caviedes-Solís, 2017

Caviedes-Solís, Itzue W., 2017, A new species of treefrog of the genus Ptychohyla (Anura: Hylidae) from Southern Mexico, Zootaxa 4317 (2), pp. 279-290 : 280-286

Ptychohyla zoque sp. nov.

Zoque Treefrog, Rana arborícola zoque ( Figures 1–2 )

Ptychohyla sp. nov. — Aguilar-López, Pineda, Luría-Manzano, and Canseco-Márquez (2016).

Holotype. UNAM-MZFC 24004 (original field number RLM 062), an adult male ( Fig. 1 A) from 6.5 km SSE Paso del Moral , Uxpanapa, Veracruz, Mexico (17° 10.84' N, 94° 35.13' W; 76 m elevation) collected on 6 July 2008 by Ricardo Luría-Manzano and José Luis Aguilar-López.

Paratypes. Eight specimens. UNAM-MZFC 1 8667 (adult female) from Chalchijapa ( Chimalapas region ), Oaxaca (17° 3.25’N, 94° 39.23’ W; 600 m elevation), collected on 9 May 1993 ; three females MZFC 24005-06 and UTA A 59271 ( Fig. 1 B) from Paso del Moral , Veracruz (17° 10.8’ N, 94° 35.39’ W; 230 m elevation), collected 5– 6 March 2009 ( Fig. 1 B) ; CARIE 1135 (adult male, Fig. 1 C) same locality as the holotype, 10 April 2013 ; CARIE 1138 (adult male) 16 May 2013 and CARIE 1215–16 (one adult male and one adult female, Fig. 1 D) 12 June 2013, from Arroyo Zarco, Uxpanapa , Veracruz (17° 11.34’ N, 94° 29.2’ W; 246 m elevation).

Measurement Males Females

(n = 4) (n = 5)

SVL 35.0–36.4 (35.8) 46.2–57.8 (54.3) Tibia length 20.3–22.0 (20.9) 28.9–35.6 (32.9) Foot length 14.2–16.7 (15.4) 20.9–26.3 (24.2) Head length 12.0–12.9 (12.5) 17.2–20.7 (19.3) Head width 12.1–13.5 (12.9) 17.4–21.7 (20.3) Diameter of eye 4.0–4.8 (4.4) 5.2–5.6 (5.5) Diameter of tympanum 1.9–2.3 (2.1) 2.4–3.0 (2.7) Diagnosis. Ptychohyla zoque is placed into the genus Ptychohyla because of characteristics described below. It has a green dorsal coloration with brown blotches and numerous irregular white spots, and the iris is pale pink with brown reticulations. There is a marked sexual size dimorphism, with males attaining 36.4 mm in SVL, and females 57.8 mm. Breeding males have small nonspinous nuptial excrescences, and lack glands on the venter (either ventrolateral or chest). Ptychohyla zoque may be distinguished from all other species in the genus Ptychohyla by its green dorsal coloration and iris pale pink. Although it superficially resembles P. acrochorda , P. erythromma , and P. sanctaecrucis in regard to dorsal coloration, P. zoque may be distinguished by its iris of pale pink with brown reticulations (whitish or silver in P. acrochorda , red in P. erythromma , and pale tan in P. sanctaecrucis ). Ptychohyla zoque can also be distinguished by the presence of small nonspinous nuptial excrescences (dark nuptial excrescences composed of spines in P. acrochorda and P. sanctaecrucis , unknown in P. erythromma ). Additionally, the new species is distinguished from P. acrochorda and P. sanctaecrucis by the absence of a chest gland in breeding males (present in the latter two species). Ptychohyla zoque and Duellmanohyla ignicolor have similar dorsal color patterns of brown blotches and numerous irregular white spots, and both share a pinkish iris. However, P. zoque can be distinguished from D. ignicolor by having nuptial excrescences and lacking noticeably thickened and extended ventrolateral gland.

Description of the holotype. An adult male, SVL 36.4 mm, tibia length 20.9 mm; tibia length/SVL 0.57; foot length 15.4 mm; foot length/SVL 0.42; head length 12.7 mm; head length/SVL 0.34; head width 12.8 mm; head width/SVL 0.35; eye diameter 4.8 mm; tympanum diameter 1.9 mm; tympanum/eye 0.39. Snout in lateral view truncate, slightly rounded in dorsal view; canthus distinct and slightly angular; loreal region concave; lips moderately thick, not flared; nostrils protuberant; internarial distance 2.2 mm; top of head flat; interorbital distance 4.3 mm. Supratympanic fold well developed, extending from posterior corner of eye above tympanum to point above insertion of forearm, covering upper edge of tympanum; tympanum distinct, rounded. Forearm moderately robust; ulnar tubercles unequally elevated. Prepollex ossified, large and blunt. Nuptial excrescences small and nonspinous, located on prepollical protrusion, inner and outer surface of Finger I, and dorsal surface of webbing between Fingers I and II; subarticular tubercles rounded, distal one on Fingers III and IV bifid; discs on fingers large, disc of the third finger slightly smaller than diameter of the tympanum; webbing formula II 1 ½— 3 III 2½— 2 IV ( Fig. 2 ). Heels overlapping when hind limbs adpressed at right angle to body; tibiotarsal articulation extending slightly beyond nostril; row of tubercles forming dermal ridge on the tarsus, extending from heel to disc of fifth toe; heel tubercle present; subarticular tubercles rounded; length of toes from shortest to longest 1-2-3-5-4; webbing formula I 1— 2 II 1½— 2 III 1— 2 IV 2 — 1 V ( Fig. 2 ). Toes moderately long; discs of toes about same size as those on fingers ( Fig. 2 ). Cloacal opening directed posteroventrally at midlevel of thighs with several curved folds below cloacal opening; cloacal sheath short; a few white tubercles below and lateral to vent. Skin on dorsum smooth; that of throat, chest, belly and ventral surface of thighs granular. Ventrolateral glands absent. Tongue cordiform with posterior notch; vomerine teeth five on right side, six on left, situated on small, elliptical elevations between ovoid internal nares. Vocal slits present on both sides.

Table 2. Selected characteristics of all species of the genus Ptychohyla . Data of P. acrochorda were obtained from Campbell and Duellman (2000), and the data of other species were obtained from Duellman (1963, 2001).

P. P. P. P. P. P. P. acrochorda dendrophasma erythromma euthysanota hypomykter legleri leonhardschultzei Distribution and Atlantic slopes of Sierra Northwestern edge of Pacific slopes of the Pacific slopes from West central Pacific slopes of the Pacific slopes

elevation Juarez, Oaxaca, México at the Sierra de los Sierra Madre del Sur southeastern México Guatemala to north- Sierra de Talamanca , of the Sierra Madre del 594 – 900 m elev. Cuchumatanes, of Guerrero at 700 – (Chiapas and extreme central Nicaragua at eastern Costa Rica Sur in Oaxaca and Huehetenango, 950 m elev. Oaxaca) and pacific 340 – 2070 m elev. and western Panamá Guerrero, Mexico at Guatemala at 1270 m slopes of Guatemala, at 700 – 1600 m elev. 700 – 2000 m elev. elev. Honduras and El

Salvador at 600 – 1200 m

elev.

…continued on the next page In life, dorsum of head, body, forelimbs, and hind limbs green with brown blotches and numerous irregular white spots concentrated on posterior part of dorsum; well-defined white stripe along upper jaw; flanks mottled with irregular white spots on pale brown background; narrow white stripe on ventrolateral edge of forearm and hand, and on ventrolateral edge of tarsus and foot; brown stripe parallel to white stripe on forearm, extending onto Finger IV; similar brown stripe on tarsus. White stripe above cloacal opening; brown patch with a few small white spots below cloacal opening. Belly, chin, chest, and ventral surfaces of limbs white. Ventral surface of Finger IV, and webbing between Fingers III and IV, dark brown; and all ventral surface of foot, including webbing, dark brown. Iris pale pink with brown reticulations.

Variation. Marked sexual size dimorphism is evident, with a ratio of sexual dimorphism of 1.52, and females attaining the greater SVL ( Table 1). Variation in body measurements among four males and five females is summarized in Table 1. Two males (CARIE 1138, 1216) and three females (MZFC, 18667, 24005; CARIE 1215) lack the scattered white spots on dorsum; additionally, one male (CARIE 1135) and two females (MZFC 24006; CARIE 1215) have a concentration of black spots along the edge of the lower lip, and UTA A 59271 have concentrated brown spots on the chin and chest that are absent in the other specimens. Variation in vomerine teeth is as follows: 5/7 (MZFC 18667); 5/4 (MZFC 24005); 6/5 (MZFC 24006); 6/6 (UTA-A 59271); 4/5 (CARIE 1135); 5/7 (CARIE 1138); 4/5 (CARIE 1215) and 4/5 (CARIE 1216).

Advertisement call. The description of the advertisement call is based on one male (SVL = 36.1 mm) recorded at 0 140 h on 4 May 2014, when it was calling on a leaf at 92 cm above ground, over a quiet pool next to a stream, in the locality of Arroyo Zarco, Uxpanapa, Veracruz (17° 11.46’ N, 94° 29.30’ W; 216 m elevation). The advertisement call of P. zoque is very soft and difficult to hear because of noise produced by other species of frogs (mainly Exerodonta bivocata ), insects, and the stream. It consists of two notes with different structure ( Fig. 3 ); in some cases the first note is immediately followed by the second, but in some instances the notes seem to be emitted independently. The first is a short, pulsed note (n = 9), with a mean number of pulses of 9.6 ± 4 (range 3–14), mean pulse duration 0.008 ± 0.003 s (range 0.005–0.011), mean interpulse interval 0.015 ±. 0 0 7 s (range 0.005–0.027), mean dominant frequency 2516.9 ± 103.5 Hz (range 2325.6–2670.1), and mean note duration 0.249 ± 0.136 s (range 0.043–0.395). The second note is shorter than the first, and is not pulsed (n= 8), it has a mean dominant frequency 2024.1 ± 220.8 Hz (range 1808.8–2497.8), and a mean note duration 0.01 ± 0.003 s (range 0.005–0.013).

Distribution and ecology. Ptychohyla zoque occurs in evergreen tropical forest, and is known from three localities in southern Mexico in the Selva Zoque, two in southern Veracruz (Paso del Moral and Arroyo Zarco) and one in northeastern Oaxaca (Chalchijapa) ( Fig. 4 ). Known elevational range is 76–600 m asl. Seven of the nine specimens that comprise the type series plus 20 additional specimens not collected (18 adult males, one adult female, and one juvenile) were observed at night, on branches or leaves at 20–228 cm above ground, and close to streams. Exceptions from this pattern were the female from Chalchijapa (MZFC 18667), which was sleeping on a leaf at 0 830 h near a stream, a male from Paso del Moral (CARIE 1135), which was found on the ground at 1504 h near a stream, and a juvenile of undetermined sex (not collected), which was on a leaf at 1730 h, approximately 30 m away from the nearest stream. Twenty-five of the 29 frogs were found in the dry season (March-May), whereas only four were observed in the beginning of the rainy season (June-July). All males had well developed nuptial excrescences regardless of month collected. An amplexing pair (CARIE 1215 and 1216) was collected in Arroyo Zarco, and was held overnight in a plastic bag, where 341 eggs were deposited a few hours later. Although all males appeared to be in breeding condition, only two observed on 11 March and 4 May 2014 in Arroyo Zarco, were calling from perches on leaves 228 and 92 cm above the ground, respectively.

Ptychohyla zoque is sympatric with other species of amphibians including Agalychnis moreletii , Anotheca spinosa , Incilius macrocristatus , I. valliceps, Hyalinobatrachium fleischmanni, Craugastor alfredi , C. berkenbuschii , C. loki, Eleutherodactylus leprus, Duellmanohyla chamulae , Exerodonta bivocata , Hypopachus ustus , Rhinella horribilis , Smilisca baudinii , S. cyanosticta, Lithobates vaillanti, Bolitoglossa alberchi, B. rufescens and B. veracrucis . The new species is relatively common in the evergreen tropical forests, being more abundant than other members of the family Hylidae such as Duellmanohyla chamulae , Agalychnis moreletii and Anotheca spinosa , but less abundant than Exerodonta bivocata and anurans in other families represented by Craugastor berkenbuschii and Incilius macrocristatus . This species appears to be sensitive to anthropogenic forest degradation, since it has been observed only in undisturbed evergreen tropical forest sites ( Fig. 5 A and B), but not in altered environments ( Fig 5 C and D) such as cattle pastures, rubber plantations and secondary forests (Aguilar- López, 2010).

Etymology. The species epithet, zoque , is an indeclinable word and refers to the Selva Zoque, a region comprised of tropical forest and covering the areas about Uxpanapa (Veracruz), Chimalapas (Oaxaca) and El Ocote (Chiapas). This region includes part of the historical range of Zoque culture, an ethnic group that has inhabited this region since pre-Columbian times.

Figures

FIGURE 1. Specimens in life of Ptychohyla zoque. A: Male holotype (MZFC 24004, 36.4 mm SVL); B: Female paratype (UTA-A 59271, 55.65 SVL); C: male paratype (CARIE 1135); D: Female and male paratypes in amplexus (CARIE 1215 and 1216).

FIGURE 2. Ventral aspect of hand and foot of Ptychohyla zoque, holotype (MZFC 24004). Scale bar = 3 mm.

FIGURE 3. Advertisement call of Ptychohyla zoque, recorded in the locality of Arroyo Zarco, municipality of Uxpanapa, Veracruz. Oscillogram (A), and audio spectrogram (B) of two calls composed by two notes with different structure.

FIGURE 4. Geographic distribution of the species of Ptychohyla in Mexico.

FIGURE 5. General habitat at Arroyo Zarco (A); Section of a stream at the same locality (B); modified habitat near the type locality (C, D).