Sunday, August 29, 2010

Tiny Frogs, and a New One from Borneo

Indraneil Das and Alexander Haas have described what has been reported as the world's smallest known frog, Microhyla nepenthicola (Family Microhylidae), in a recent issue of Zootaxa. The frog inhabits Gunung Serapi mountain, located in Kubah National Park, on the island of Borneo. Adult male M. nepenthicola are 10.6 to 12.8 mm and live in the pitcher plant Nepenthes ampullaria,  which has a globe-like pitcher and grows in damp, shady forests.  Females deposit their eggs on the sides of the pitcher, and tadpoles  grow in the water that has collected inside the plant. [Full citation: Das, I. and A. Haas. 2010. New species of Microhyla  from Sarawak: Old World’s smallest frogs crawl out of miniature pitcher  plants on Borneo (Amphibia: Anura: Microhylidae). Zootaxa, 2571 37-52.]

Tiny frog species have been discovered in abundance in recent decades and media reports claiming title to the world's smallest frog have been almost as numerous. The Brazilian Gold Frog, Brachycephalus didactylus (Izecksohn, 1971)(Family Brachycephalidae) grows to a tiny 9.8 mm and appears to still hold the title to the World's smallest frog. But there are many runners-up. Hoogmoed and Lescure described Adelophryne adiastola (Family Eleutherodactylidae) from Letica, Colombia in 1984, it has a body length of 12.9 mm. In 1986, Lynch descibed Nobella (Phyllonastes) heyeri (Family Strabomantidae) from Loja province Ecuador, males were 12.9 to 14.1 mm and females were 13.1 to 15.9 in body length. In the same paper Lynch described Phrynopus bagrecito (Family Strabomantidae)  from Cuzco, Peru; this species has males that are 13.8 to 16.3 mm and  females that are 14.4 to 18.6 mm long. The small  Monte Iberia Eleuth, Eleutherodactylus iberia, Family Eleutherodactylidae), was described from Cuba in 1996 by Estrada and  Hedges; fully grown adult males are 10.5 mm and females are 9.8 mm; it seems to most closely rival Brachycephalus didactylus for the smallest body size in frogs. Nyctibatrachus minimus (Family Nyctibatrachidae) was described by  Biju et al. in 2007 from southern India; its males average 12.3  mm in body length. Lehr and Coloma (2008) described Pristimantis andinognomus (Family Strabomantidae) . They found a maximum snout–vent length of 17.9 mm  with males averaging 12.3 mm and females averaging 15.9 mm. Lehr and Catenazzi (2009) described Noblella pygmaea (Family Strabomantidae), commonly called Noble's Pygmy Frog; females measured less than half an inch (12.5 mm) in body length, whereas males are just a bit longer than 1 cm. More recently,Teran-Valdez and Guayasamin (2010) described Pristimantis minimus from Ecuador with a maximum body length of 13.7 mm.  Below is a group of photos of some of these tiny frogs taken from a variety of sources on the web. Being small allows these species to exploit resources unavailable to larger frogs. JCM

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