Mountain Treefrog

Hyla wrightorum is a species of frog with a snout-vent length of 19 – 51 mm. It has a blunt snout, with a prominent and smooth canthus rostralis that curves inwards. The nostrils sit underneath the edge of the canthus rostralis. The distance between the nostrils is about equal to the distance between the nostril to the eye. The region around the nostrils is somewhat raised. There is a faint shallow groove between the nostrils. The skin is smooth on the back, granular on the underside. There is primitive webbing between the first three fingers, and no webbing on between the other fingers. The fingertips are slightly enlarged. The legs are relatively long, and the toe tips are smaller than the fingertips. The tarsal fold is prominent, as are the inner and outer metatarsal tubercles. The feet are slightly webbed. Two proximal subarticular tubercles are found on the fourth toe. The supernumerary tubercles on the hands and feet are prominent (Taylor 1938, Stebbins 2003).It is similar to H. eximia in appearance, though it is larger in size, has longer legs, a wider and less pointed head, a relatively longer first finger, a darker lower jaw, and a lighter colored thigh. Additionally, H. wrightorum has a shorter, higher frequency call than H. eximia (Taylor 1938).In life, it has a bright green back, with a dark line running down the sides from the nostril, to the eye and tympanum, and sometimes even down to the groin, that may be broken up into smaller sections. The underside is golden and orange, with a slight hint of green. There are uneven dark brown spots and stripes on the arms, legs, and back, as well as dark stripes on the legs and upper arms. The iris is a metallic brown color. In preservative, the backside is gray and lavender in color. The line running down each side is brown, as are the spots and stripes on the back and the limbs. The underside is white, with faint pigmentation on the chin, throat, and the underside of the limbs. The upper legs and groin show some slight brown pigmentation (Wright and Wright 1933, Taylor 1938, Duellman 1970).The dark spots on the back are highly variable between individuals. Additionally, the dark line running down the sides is broken up differently between individuals (Wright and Wright 1933, Taylor 1938, Duellman 1970).The species authority is: Taylor, E. H. (1938). "Frogs of the Hyla eximia group in Mexico, with descriptions of two new species." University of Kansas Science Bulletin, 25(19), 421-445.It is part of the H. eximia species complex. Taylor originally described it as a separate species from H. eximia in 1938, before being reassigned as a subspecies of H. eximia in 1953 by Schmidt, and subsequently as a subspecies of Pseudacris regilla in 1966 by Jameson et al. In 1977, Renaud suggested that H. wrightorum is indeed its own separate species, which was later confirmed in 2001 by Duellman (Sullivan 1986, Gergus et al. 2004, Hammerson 2004).The specific epithet, wrightorum, is named after American herpetologists Anna Allen Wright and Albert Hazen Wright (Taylor 1938).The existence of two disjoint populations, one extending from central Arizona into central western New Mexico, and the other from southern Arizona to Mexico, has led to measurable genetic variation between allopatric individuals. However, it is not enough to fully elevate either population to its own species, suggesting the populations were separated relatively recently (Gergus et al. 2004).

It is found from the mountains of central Arizona, specifically the Petran Montane Conifer Forest Biome along the Mogollon Rim, southeastward to the western part of central New Mexico. There is also an isolated population in Huachuca Mountains, Cochise County, Arizona, that extends southward to the Sierra Madre Occidental of Chihuahua, Mexico. It may extend to the region just north of Mexico City, though this is uncertain due to difficulties differentiating between this species with the similar H. eximia within this contact zone. It has an altitudinal range of 910 – 2900 m asl (Sullivan 1986, Hammerson 2004).

It frequents ponds, slow-moving streams, and other relatively lentic bodies of water in semi-arid regions by pine and fir forests. It can be found on the ground or on trees and other vegetation. Breeding occurs in slow-moving bodies of water. Males call during the breeding season, and the dominant frequency is of their call is inversely proportional to their snout-vent length. The average dominate frequency was 1.86 kHz and ranged from 1.70 - 2.30 kHz with a pulse rate between 83.0 - 156.0 p/s and a call duration lasting between 0.13 - 0.24 seconds (Sullivan 1986, Hammerson 2004).

It is assumed to be common within its range. No other information is available on trends and threats in this species (Hammerson 2004).

Wright's mountain tree frog (Dryophytes wrightorum) is a species of frog in the family Hylidae found in Mexico and the United States. Its natural habitats are temperate forests, temperate grassland, rivers, and freshwater marshes. Dryophytes wrightorum has been regarded as a synonym of Dryophytes eximius, the mountain tree frog, which is listed as the state amphibian of Arizona. As presently circumscribed, Dryophytes eximius is endemic to Mexico and does not occur in Arizona. It is the state amphibian of Arizona.