Hydrops martii, also known commonly as the Amazon water snake and cobra d'água in Brazilian Portuguese, is a species of snake belonging to the subfamily Dipsadinae of the family Colubridae. The species is native to northern South America.
Taxonomy The species, Elaps martii, named after German botanist Carl Friedrich Philipp von Martius (1794–1868), was first described by German herpetologist Johann Georg Wagler in 1824. viii + 75 pp. + Plates I–XXVI. (Elaps martii, new species, pp. 3–4 + Plate II, figure 2. (in Latin and French). The species was reassigned to the genus Hydrops by Wagler in 1930. vi + 354 pp. + one plate. (Hydrops martii, new combination, p. 170). (in German and Latin).
Elaps martii , is the type species of the genus Hydrops . Hydrops is the type genus of the tribe Hydropsini , which consists of the genera Helicops, Hydrops, and Pseudoeryx.
Description Hydrops martii may attain a total length (tail included) of . It has smooth dorsal scales, which are arranged in 17 rows at midbody. 1,073 pp.
Geographic distribution Hydrops martii is found in Brazil, Colombia, Ecuador, Peru, and Venezuela. In Brazil, this species has been found in the Amazonas, (in Spanish). Amapá, Maranhāo, Pará, and Roraima states. H. martii has also been recorded in the Loreto and Ucayali departments of Peru, and has only been documented in the Guainía department of Colombia.
Habitat The preferred natural habitat of Hydrops martii is floodplains within rainforest, at altitudes from sea level to .
Behavior The species Hydrops martii spends the majority of its time in small streams, but it is believed that it may come onto land for foraging.
Biology Sexual dimorphism Males of Hydrops martii are reported to be smaller than females.
Reproduction The species H. martii is oviparous, and clutch size ranges from 7 to 23 eggs. The breeding season of this species is not well known, but pregnant females have been found by researchers in March, July, September, and October.
Diet Hydrops martii has only been reported to eat fish and is therefore is thought to be a fish specialist. (in Portuguese). Stomach contents of H. martii most commonly contained fish belonging to the orders Gymnotiformes, Synbranchiformes, and Siluriformes. (in Portuguese). Confirmed fish species include Callichthys callichthys (cascarudo), Pimelodella cristata (commonly referred to as a bagre in Brazil), Hoplias malabaricus (wolf fish), and Erythrinus erythrinus (red wolf fish). The family Synbranchidae, consisting of swamp eels, has also been found in its diet.
Foraging is normally done during the evening and night, following the activity of its prey.
As prey H. martii has been found in the stomach of Serrasalmus rhombeus (redeye piranha) and has also been reported to be eaten by Micrurus lemniscatus (South American coral snake), caimans, and aquatic fishes and snakes.
Defensive behavior Defensive behavior has not yet been reported in H. martii.
References
Further reading xi + 382 pp. + Plates I–XX. (Hydrops martii, p. 187). 189 pp. (Hydrops martii, p. 100).