E.—17 specimens: A narrow dark stripe from snout, through nostril and eye, over tympanum, to vent, enclosing a unicolor dorsum (reddish tan to yellowish tan in life); heels pale tan or yellow above; anal patch black. A faint dermal ridge from posterior edge of eyelid to rump, or part way to rump.
F.—2 specimens: Mottled brown and cream-color above; upper lips and upper arms white. A dermal fold from posterior edge of eyelid to rump; scattered pustules on dorsum.
Some of these color variants are assignable to names proposed by Taylor: "A" and "B" undoubtedly are M. pygmaeus (Taylor, 1936a); "C" probably is M. pygmaeus; "D" is referable to M. minimus (Taylor, 1940d) in most characteristics, although the coloration is more nearly like that of M. lineatissimus (Taylor, 1941a), a larger species characterized by a relatively long hind limb; "E" apparently is M. imitator (Taylor, 1942b); "F" is M. albolabris (Taylor, 1940d). Examination of series of these frogs from other parts of México shows a similar composition of color variants. Of 78 specimens from the Río Sarabia and the village of Sarabia in Oaxaca (UMMZ 115428-37), 57 are "A," six are "D," three are "E," and 12 are "F"; of 22 specimens from Teapa, Tabasco (UMMZ 113829), 11 are "A," five are "D," two are "E," and four are "F"; of 33 specimens from Potrero Viejo, Veracruz (USNM 115447-58, 115461-71, 116840-2, 116864-70), ten are "A," 13 are "E," and ten are "F"; of 31 specimens from La Esperanza, Chiapas (USNM 115477-9, 116827-39, 116849-63), 28 are "A" and four are "F."
It is highly doubtful if these color variants are actually distinct species. Goin (1950 and 1954) in his studies of inheritance of color pattern in West Indian species of the genus Eleutherodactylus has shown that similar color pattern variants come from the same clutch of eggs; furthermore, Goin has worked out the genetic ratios of certain of these variants. Heathwole (in litt.) obtained "normal" specimens and individuals having a broad middorsal stripe ("C" in figure 9) from a clutch of eggs of Eleutherodactylus gollmeri. The presence of a broad middorsal yellow stripe is common in Eleutherodactylus rugulosus.
Perhaps the most interesting aspect of variability in color pattern in Mexican eleutherodactylids is the parallelism between members of the Eleutherodactylus rhodopis-group and some members of Microbatrachylus. In the former group there are white-lipped individuals (Eleutherodactylus beatae Boulenger), individuals having a unicolor reddish or yellowish dorsum (E. dorsoconcolor Taylor), and individuals having a dorsal pattern of irregular longitudinal brown and cream-colored streaks (E. venustus Günther). In the humid forests of southern Veracruz, northern Oaxaca, and Chiapas members of both groups occur sympatrically. A proper understanding of the evolutionary significance of these variants in the two groups, as well as proper allocation of the presently recognized species, must await experimental evidence based on studies of the inheritance of color pattern. Nevertheless, at present it is apparent that certain characters, especially the nature of the dermal folds and pustules, and the color pattern, are of little taxonomic value in distinguishing "species" of Microbatrachylus. The data derived from a study of the large series from Arteaga, together with that from the other series examined, suggests that Microbatrachylus albolabris, imitator, minimus, and pygmaeus are morphotypes of one species. Of these names, pygmaeus is the oldest. Consequently Microbatrachylus pygmaeus has been used here for the series from Arteaga.
Although Microbatrachylus hobartsmithi, a species distinguished from all of the above by the presence of tubercles on the outer edge of the tarsus, is known from Michoacán northward into Nayarit, Microbatrachylus pygmaeus previously has not been known north of Guerrero, where it occurs in habitats similar to that in which it was collected at Arteaga.
Eleutherodactylus augusti cactorum Taylor
Eleutherodactylus cactorum Taylor, Univ. Kansas Sci. Bull., 25:391, July 10, 1939.—20 miles northwest of Tehuacán, Puebla, México.
Eleutherodactylus augusti cactorum, Zweifel, Amer. Mus. Novitates, 1813:20, December 23, 1956.
Cherán; Coalcomán; Uruapan.