leptodactylid distribution.

ANALYSIS OF CHARACTERS

In México and northern Central America approximately 55 species of eleutherodactyline frogs (Eleutherodactylus, Syrrhophus, and Tomodactylus) are known. Four genera can be recognized on the basis of the nature of inguinal glands, morphology of the hands and feet, and certain osteological features.

Fig. 1. Tomodactylus angustidigitorum (UMMZ 114305, × 4.5) illustrating the lumbo-inguinal gland typical of members of the genus. From a kodachrome by Wm. E. Duellman.

Glands

Leptodactylids have a variety of glands that have been used as generic characters. Smith and Taylor (1948) regarded the so-called inguinal gland as a generic character in Mexican eleutherodaycty-lines. Lynch (1965) showed that Eleutherodactylus and Microbatrachylus cannot be separated by the nature of the gland or the condition of the prevomers (dentate or not). Syrrhophus and Tomodactylus, as defined by Smith and Taylor (1948), are not generically distinct because of overlap in the condition of the prevomers and in the development of the gland. Firschein (1954) stated that Syrrhophus differed from Tomodactylus by having an axillary gland, but it is now known that one species of Syrrhophus lacks the gland.

The inguinal glands of Eleutherodactylus and Syrrhophus, if present, are diffuse, irregular in outline, and generally not prominent; in Tomodactylus the gland is higher on the body (a lumbo-inguinal gland), compact, oval in outline, and prominent (Fig. 1). Axillary glands occur in most Syrrhophus but are not known in Tomodactylus or Eleutherodactylus.

Hands and feet

The tips of the digits are laterally expanded in most Eleutherodactylus, Syrrhophus, and Tomodactylus. Two species of Eleutherodactylus (augusti and tarahumarensis) and two Tomodactylus (angustidigitorum and grandis) lack any expansion of the digital tips. All but two of the species of eleutherodactyline frogs (E. augusti and E. tarahumarensis) have a transverse groove across the tips of the digits (Fig. 2).

Fig. 2. Palmar views of the hands and lateral views of the tip of the third digits of Eleutherodactylus alfredi (left, KU 93994, × 5) and Hylactophryne augusti (right, KU 102594, × 3).