Descriptions of New Hylid Frogs From Mexico and Central America

Axillary membrane absent; arms robust, forearm not noticeably heavier than upper arm; distinct transverse fold on wrist. Fingers long, moderately slender; length of fingers from shortest to longest, 1-2-4-3; discs moderately large, that on third finger larger than tympanum; webbing vestigial; subarticular tubercles small, conical; terminal tubercle on fourth finger somewhat flattened; supernumerary tubercles small, in one row on proximal segment of fourth finger and in two rows on proximal segments of other fingers; prepollex greatly enlarged, barely bifurcate; spines not protruding through skin; distal spine much longer than proximal one (Fig. 2). Heels overlap by about one-third length of shank when hind limbs adpressed; tibiotarsal articulation extends slightly beyond snout; heavy transverse dermal fold on heel; inner tarsal fold heavy, extending full length of tarsus; outer tarsal fold absent; inner metatarsal tubercle high, elliptical, visible from above, outer metatarsal tubercle absent. Toes long, slender; length of toes from shortest to longest, 1-2-5-3-4; fifth toe nearly as long as third; discs small; subarticular tubercles small, round; supernumerary tubercles small, in single row on proximal segment of each digit; toes about three-fourths webbed; webbing extending from base of disc of first toe to base of penultimate phalanx of third, from base of disc of third to base of penultimate phalanx of fourth to base of disc of fifth toe.

Anal opening directed posteroventrally at level of mid-thigh; anal sheath long with membranous connection to posterior surfaces of thighs. Skin on dorsal surfaces finely tuberculate; that on throat, chest, belly, and ventral surfaces of thighs granular, that on ventral surfaces of arms and shanks smooth. Tongue nearly round, free posteriorly for about one-fourth its length, barely notched behind. Upper jaw shallowly notched medially. Maxillary-premaxillary teeth 38-35; prevomerine teeth 5-5, situated on small elliptical elevations between quadrangular choanae; vocal slits absent.

Color (in preservative): uniform dull brown above and creamy yellow below; flanks brown with creamy yellow mottling and dark brown spots in groin; anterior surfaces of thighs creamy yellow with two broad, vertical, dark brown bars proximally and two narrower, dull brown bars distally; posterior surfaces of thighs brown with dark brown vertical bars, interspaces cream-colored or brown. Ventral surfaces of shanks creamy yellow with bold brown reticulations.

Variation.—The paratypes are smaller, having snout-vent lengths of 48.3 and 41.8 mm. In these specimens the ratio of the length of the tibia to the snout-vent length is 55.9 and 57.9 per cent, and the ratio of the diameter of the tympanum to the diameter of the eye is 47.3 and 43.6 per cent, respectively. Both specimens have 4-4 prevomerine teeth; one specimen has 37-36, and the other has 40-37, maxillary-premaxillary teeth. In these small specimens the supratympanic fold is thin, and the arms are not so robust as in the holotype. In one specimen (KU 58873) the tongue is not notched posteriorly. The terminal subarticular tubercle on each fourth finger is broad and flattened in UIMNH 40837, but conical in KU 58873. Both specimens have bold creamy-yellow and dark brown mottling on the flanks and dark brown reticulations on the ventral surfaces of the shanks. There are two dark brown vertical bars on the anterior and posterior surfaces of each thigh in KU 58873 and three bars on each surface in UIMNH 40837.

Comparisons.—Plectrohyla hartwegi differs from all known species in the genus by having boldly mottled flanks, dark reticulations on the ventral surfaces of the shanks, and dark vertical bars on the shanks. In all of the other species the anterior and posterior surfaces of the thighs are unmarked, and the flanks are either plain or marked with small spots or flecks. Structurally, P. hartwegi belongs in the guatemalensis group of the genus, containing avia, glandulosa, guatemalensis, and pycnochila. The species in this group lack vocal slits and have either large, rectangular, or bifid prepollices. Plectrohyla hartwegi differs from all of these species, except pycnochila, by having a tuberculate, instead of a smooth, dorsum, and hartwegi differs from pycnochila by having a bifid, instead of a rectangular, prepollex.

Remarks.—The known distribution of Plectrohyla hartwegi includes three localities at elevations of 1000 to 2050 meters in the Sierra Madre of Chiapas and extreme eastern Oaxaca. The specimen from Parajé El Triunfo was found in a rocky stream in cloud forest at an elevation of 2050 meters. One Plectrohyla sagorum was obtained from the same stream.

Eizi Matuda sent the holotype to the late Dr. Norman Hartweg, who recognized that the specimen was unique but was reluctant to name the species on the basis of a single specimen. Now that two additional specimens are available, it seems appropriate to associate Hartweg's name with this new species of Plectrohyla, a genus that Hartweg first adequately defined.

LITERATURE CITED

Adler, K.

Duellman, W. E.

Starrett, P.

Transmitted July 11, 1967.

PLATE 17

Upper figure, Hyla xanthosticta (KU 103772);
lower figure, Hyla pseudopuma infucata (KU 101770). × 2.

PLATE 18

Upper figure, Hyla pellita (KU 100973);
middle figure, Hyla pellita (KU 100970);
lower figure, Hyla siopela (KU 100977). × 2.

PLATE 19

Upper figure, Hyla altipotens (KU 101001);
lower figure, Plectrohyla hartwegi (UMMZ 94428). × 1.

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