Telmatobius thompsoni Wiens 1993

Telmatobius thompsoni belongs to a clade where there are no proposed synapomorphies supporting the monophyly of Telmatobius, Telmatobiini, Telmatobinae, or Leptodactylidae, though the presumptive synapomorphies for the group are (1) frontoparietals fused posteriorly, and (2) nuptial excresence on Finger 1 only (which are not universal across all Telmatobius). T. thompsoni differs from its congeners by the following combination of characters: (1) Premaxillary teeth present, (2) tympanum absent, (3) nuptial spines small, distinctly conical, and on dorsal and ventral sides of thumb, (4) dorsal coloration is a dull gray or brown with fine speckling of small dark spots, ventral coloration is a dull yellow with small, dull gray or brown spots, (5) max SVL for males is 68.9 mm, and 77.3 for females. T. thompsoni’s nuptial spines are slightly larger than those present on T. brevipes and T. ignavus which it shares its distribution. Head is equal to or slightly narrower than the body; head is wider than it is long (head length is 28.7-33.1% SVL, head width is 39.2% of SVL). Nostrils are located at anterior terminus of snout. Canthus rostralis is indistinct when viewed dorsally or laterally. Tympanum is absent with an annulus still present. Supratympanic fold moderately well developed, extending from the posterior corner of the eyelid to the anterior point of insertion of the forelimb. There is a vertical fold of skin posterior to corner of the jaw extending from the supratympanic fold to the throat. Relative finger lengths are: III>IV>I>II. Length of toes in decreasing order: IV>III>V>II>I.

T. thompsoni is only known from the type locality in the Cordillera Occidental.

The type series was collected in a densely vegetated roadside marsh in an open pasture in very humid Subalpine Páramo life zone. Frogs were active and abundant in pools and running water by day.