This species has been recorded from the type locality of Totontepec, Sierra Mixes, and from one other locality west of Zacatepec, very near the type locality in Oaxaca, Mexico. The specimens from the type locality were collected between 1,780 and 1,896m asl, and the specimens from the second locality were collected at 1,360m asl. The exact limits of its distribution are not known, but it is believed to have a restricted distribution.
Habitat and Ecology
It inhabits tropical cloud forest. The adults have been found on vegetation along streams; larvae have been found in a pool in a small stream. It is presumed to be sensitive to habitat modification.
It is known only from the type series, and two other specimens recently collected from the second locality.
The forest at the type locality has been cleared and no suitable habitat remains in the area. It is unlikely that any animals now remain at the type locality (Ustach et al. 2000). The second locality is also suffering from severe habitat fragmentation and the remaining habitat is likely to disappear in the near future. Chytridiomycosis is also a threat to this species, as it is a high-elevation, stream-dweller, and declines due to the disease have already been detected amongst other species of this genus.
The species has not been recorded from any protected areas. Survey work is required to determine the current population status and range of this species, and particularly to ascertain whether or not it still survives at the type locality. In view of the threat of chytridiomycosis, ex-situ populations might need to be established.
This species was previously included in the genus Hyla but has recently been moved to the genus Plectrohyla (Faivovich et al. 2005).
Georgina Santos-Barrera, Joseph Mendelson III 2006. Plectrohyla calthula. In: IUCN 2014