Brazilian snake-necked turtle

The specific name, maximiliani, is in honor of German naturalist Prince Maximilian of Wied-Neuwied.[4]

First described as Emys maximiliani by Mikan (1825),[1] it was subsequently moved to the genus Hydromedusa by Wagler (1830).[5] Several other species described later have since been synonymized with this species.[3] There are no recognised subspecies.[3]

The Brazilian snake-necked turtle is a small species reaching a straight carapace length of between 10–20 cm (3.9–7.9 in) with a weight of 120–520 g (4.2–18.3 oz).[3] The carapace of the adult is oval in shape varying in color from dark gray, through to dark or light brown.[3] The plastron is a yellow or cream color. The species has a moderate-sized head with a small snout and yellowish jaws, with no barbels on the chin. The iris is black.[3] The dorsal surface of the head, neck and limbs are olive green to gray in color with a lighter cream-colored ventral surface.[3]

The Brazilian snake-necked turtle is endemic to southeastern Brazil, in the states of Bahia, Minas Gerais, Espírito Santo, Rio de Janeiro and São Paulo.[3] The distribution is associated with the mountainous Atlantic rainforest. As a generalization it is found in mountain streams above 600 m (2,000 ft).[6]

The species is found in shallow streams from 15 to 100 cm (6–39 in) in depth, with clear, cold water and sandy or rocky substrates.[7] Because of the dense canopy and closed understory of the forests the streams receive little sunlight making basking only possible in gaps along the stream.[8]

Some populations of this species, H. maximiliani, occur within protected areas and are hence afforded some protection from deforestation and pollution which are considered major threats.[3] In regions outside these protected areas the species may be becoming fragmented and may therefore become increasingly vulnerable in the future.[3]