Brazil is the world's hotspot for miniaturized Craniata, with the smallest members of Squamata, Amphibian and Actinopterigii from across continental America being endemic to Brazil. More than that, our smallest Amphibia and Actinopterigii are the smallest in the entire Western Hemisphere and are among three of their groups worldwide. The smallest Brazilian Squamata is second in New World only to some nanolizards in the Caribbean on the continent.
Actinopterigii ▸ two of them three smallest Actinipterigii (and smallests among all eight pisces classes) are two Brazilian species from endemic genus Leptophilypnion (Eleotridae), L. fittkaui T. R. Roberts, 2013 known only from Rio Negro in Amazonas state, and L. pusillus T. R. Roberts, 2013 known only from Tapajós River in Para state (Roberts et al., Int. Jour. Icth., 2013), with mature lengts of 9.1 to 9,3mm. Over a hundred of Neotropical fishes run as miniaturized, with mature age below 26mm (Piza et al., Neotropical Ichtyology, 2014).
Amphibia ▸ Brachycephalus didactylus Izecksohn, 1971 (Brachycephalidae) is the third smallest amphibia worldwide (Rittmeyer, PlosOne, 2012), known only from the central part of the state of Rio de Janeiro and Serra das Torres in extreme southern Espírito Santo state, both in SE Brazil, in forested areas (AmphibiaWeb), with 9 to 10.2 mm in adult forms. Other small member of this genus, B. hermogenersi, is the sixth smallest known amphibia.
Squamata ▸ smallest squamata from Brazil and South America, possibly in mainland New World, is Coleodactylus natalensis Freire 1999 (Sphaerodactylidae), known only from remants of Atlantic Forest in Rio Grande do Norte state, NE Brazil, with males and females reach a maximum snout-vent length of 22 and 24 mm (Lisboa, Sales & Freire, Zoologia, 2012). Other species in this genus are very small, and are distributed from Venezuela, Guianas and Brazil except southern parts. Miniaturized lizards also occur in Gymnophthalmidae.
