Leptodactylus chaquensis Cei 1950

Diagnosis A large-sized Leptodactylus with short legs; snout truncate; postlabial. gland smaller; hollowed dark band on the tympanum; gland on mouth joint curved, slightly larger than tympanum; vocal sacs paired; belly immaculate, posterior surface of the thigh olive green uniform without bands.

Known from Northern Argentina (Córdoba, Chaco, Corrientes, Entre Ríos, Formosa, Jujuy, Salta, Santiago del Estero, Santa Fe, Tucumán), Chaco and western oriental region of Paraguay; northern Uruguay (Artigas and Salto), lowland Bolivia; and parts of western (Acre) and southern Brazil (Mato Grosso do Sul, Rio Grande do Sul).

Adult morphology Snout-vent up to 85 mm in females. Head slightly wider ,than large, rounded. Snout obtuse, more truncate in lateral profile. Upper jaw moderately projecting beyond lower. Nostrils superolateral; their interval larger than their distance from tip of snout, and than the interocular distance, which is narrower than the upper eyelid. Canthus rostralis rounded; loreal region concave. Eyes prominent, laterally located. Maxillary teeth developed; vornerine teeth in two blunt, close patches between grid behind the choanae. Tongue subcircular, slightly notched behind. Tympanum distinct, about 3/4 of the eye diameter, a strong curved supratympanic fold, reaching the axilla; enlarged glands at the mouth joint, slightly larger than tympanum. Fingers free, imperfectly fringed, rounded on the tip. Rate of the finger lengths: II-IV-I-III. Metacarpal tubercles moderate; subarticular tubercles, blunt, prominent. Foot as in Leptodactylus latrans. Males with a marked seasonal cycle. Two paired, blackish vocal sacs. Skin slightly glandular on the back, with five pairs of longitudinal folds. No femoral gland evident. Ventrally smooth; unda surface of thighs granular. Discoidal fold present. Dorsally dark green or brownish, with eight 1ongitudinal light stripes and rounded spots. Posterior surface of thighs greenish. Triangular interocular spot evident. Belly white, unspotted. Larval morphology Very similar to L. latrans, with a few differences in shape of snout, long of tail and position of spiracle.

LC. Least Concern.

Leptodactylus chaquensis Cei

MATERIAL.—USNM 241322 (one specimen dissected, stage 37, SVL 18.1 mm). Collected from a pond in the city of Embarcación, Salta, Argentina, 31 December 1971.

REFERENCE.—The external morphology of the L. chaquensis larva has been reported and illustrated by Cei (1980:351, fig. 148).

VENTRAL ASPECT.—Buccal Cavity: Floor of mouth triangular length about equal width. Two infralabial papillae on each side, 1 pair near midline, much larger pair directly lateral to medial pair; papillae with rough knobby margins; 2 or 3 pustulations anterior to infralabial papillae. Three anteriorly to posteriorly flattened lingual papillae; large one on midline, bifurcated at tip, smaller two lingual papillae posterolateral to larger median one. BFA broadest anteriorly, narrowing gradually posteriorly, then abruptly near posterior limit; 10–15 BFA papillae on each side; largest BFA papillae medial to buccal pockets; most thin and conical, some with bifurcated tips. No prepocket papillae. Five or six papillae lateral to BFA just posterior to medial edge of pockets. Buccal pockets large; transverse; not perforated. Free velar surface of slightly longer than average length; spicular support obvious through epithelium of buccal floor; spicules long, thin, and stiff; posterior edge of ventral velum with 3 long, distinct, posteromedially directed, marginal projections on each side directly above the tops of the 2nd, 3rd, and 4th filter plates and 2 short papillae on either side of median notch; median notch large; very conspicuous secretory pits densely distributed on margin and marginal projections of velum.

Pharyngeal Cavity: Branchial baskets oval, almost round, with long axis from anterolateral to posteromedial; area of both branchial baskets about equal to rest of buccal floor area; branchial baskets deep; filter cavities about same size, 2nd less than 25% larger than 1st and 3rd. Two medial filter plates with gently upwardly curved dorsal edges; more lateral filter plates with straight dorsal margins; filter plate length about equal to height; slightly imbricate; cb 1 with 12 filter rows, cb 2 with 12, cb 3 with 12, cb 4 with 9. Filter mesh dense; extensively branched with conspicuous tertiary folds. Filter rows wide, abutting. Filter canals not as wide as rows, fully canopied. Branchial food traps of average size with conspicuous secretory ridges. Glottis entirely exposed when viewed from above, small with tall, thin lips; no laryngeal disc. Esophageal funnel narrow, but esophagus relatively large.

DORSAL ASPECT.—Buccal Cavity: Mouth relatively narrow, roof 20% longer than wide; long prenarial area, nares about 25% distance from front of mouth to esophagus; median ridge located about 40% distance from front of mouth to esophagus. Prenarial arena with 5 or 6 random pustulations plus a transverse median ridge with a gently curved, biconcave margin and a medial cleft. Nares of moderate size, transversely oriented; anterior narial wall thick, not exceptionally high, ending medially with a medially directed papilla; narial valves thin, 5 times as long as tall, no distinctive projection. Postnarial arena with few pustulations and 1 irregular, short, pustulate papilla on each side. Median ridge triangular, ending in 1 truncate papilla; anterior surface pustulate. Lateral-ridge papillae complex, large, elkhorn-shaped, far lateral and slightly anterior to median ridge. One to four small lateral-roof papillae. BRA triangular, relatively narrow; 5 attenuate, simple BRA papillae on 1 side, 8 on other; 30–40 pustulations scattered evenly about BRA. Glandular zone with distinct anterior margin of secretory pits; zone of uniform anterior to posterior dimension, about length of roof of mouth. Free medial of dorsal velum pustulate and papillate, larger and more medial papillae pointing posteriorly; dorsal velum narrowly interrupted on midline.

Pharyngeal Cavity: Pressure cushions distinct; lateral cushions irregular in shape, more medial cushion oriented in anteromedial to posterolateral plane; medial cushion large, vaguely pyramid in shape. Ciliary groove shallow and wide.

Leptodactylus macrosternum is a species of frogs in the family Leptodactylidae. It is found in northern Argentina and adjacent eastern Bolivia, Paraguay, northern Uruguay, and southern and western Brazil. The specific name chaquensis refers to the area of Gran Chaco in Argentina. Common name Cei's white-lipped frog has been coined for it, although this particular species lacks the light upper lip stripe common in the genus.