Hydromedusa maximiliani (Mikan 1825) – Brazilian Snake-necked Turtle, Maximilian’s Snake-necked Turtle, Cágado-da-Serra, Cágado-Pescoço-de-Cobra

Summary. – Maximilian’s Snake-necked Turtle or the Brazilian Snake-necked Turtle, Hydromedusa maximiliani (family Chelidae), is a relatively small freshwater turtle species, with male and female straight-line carapace lengths (SCL) up to 203 mm and 169 mm, respectively. The species occurs primarily in higher-elevation lotic environments, and is endemic to the Atlantic rainforest of southeastern and eastern Brazil, inhabiting streams and rivers in hilly terrain, often using submerged logs, rocks, and streambank crevices as refuges. Individuals are largely sedentary, although males and gravid females exhibit large seasonal movements associated with reproductive periods. Clutch size ranges from 1–3 eggs, but usually two. The species is carnivorous, feeding on aquatic macroinvertebrates, crustaceans, insects, and other small prey, as well as carrion. Habitat loss from deforestation, mining, burning, and pollution are major threats, and populations from outside protected areas are more vulnerable to decline. Conservation efforts need to focus on habitat protection and monitoring of populations.

Distribution. – Brazil. Endemic to hilly regions of the southeastern and eastern Brazilian Atlantic Rainforest, occurring in Bahia, Espírito Santo, Minas Gerais, Rio de Janeiro, and São Paulo.

Synonymy. – Emys maximiliani Mikan 1825, Chelodina maximiliani, Hydromedusa maximiliani, Hydraspis maximiliani; Emys maximiliana Gray 1830 (nomen novum), Hydromedusa maximiliana; Chelodina flavilabris Duméril and Bibron 1835, Hydromedusa flavilabris, Chelomedusa flavilabris; Hydromedusa subdepressa Gray 1854; Hydromedusa depressa Gray 1856 (nomen novum), Chelomedusa depressa; Hydromedusa bankae Giebel 1866.

Subspecies. – None recognized.

Status. – IUCN 2026 Red List: Endangered (EN A2ce+4ce; assessed 2023 [in press]); Previously: Vulnerable (VU, assessed 1996); CITES: not listed; Brazil: Least Concern (LC) (national), LC (São Paulo); VU (Minas Gerais); VU (Espírito Santo); EN (Bahia).