Aquatic Snake Blog

Helicops carinicaudus (Wied-Neuwied 1825)

Helicops carinicaudus (Wied-Neuwied 1825) Coluber carinicaudus Wied-Neuwied 1825: 300. Holotype: AMNH 3365, a 909 mm specimenHomalopsis carinicaudus — Schlegel 1837: 350Helicops carinicaudus — Wagler 1830: 170. Distribution. Brazil (Espirito Santo, Rio Grande do Sul), Colombia. Read more

July 10, 2016
Helicops apiaka Kawashita-Ribeiro, Ávila & Morrais, 2013

Holotype: UFMT-R 8512, adult male, collected on 27 October 2009 by Carolina L. Cavlac. Diagnosis. Helicops apiaka sp. nov. is distinguished from all congeners by the following combination of characters: (1) dorsal scales in 21/21/19 rows in males and 23/21/19 rows in females; (2) subcaudals 79–103 (n = 14; 95.1 +/- 5.8) in males and 80–84 (n… Read more

July 10, 2016
Helicops gomesi Amaral 1921

Helicops Gomesi Amaral 1921: 7 Holotype: Institute Butantan 1,843. Type locality: Costa Pinto Station, Railway Sorocaba, São Paulo, Brazil. Distribution: Brazil (Sao Paulo). Original description. Amaral, A. 1921. Contribution to the knowledge of the Brazil snakes. Part I Four nine species of snakes brasileires. Anex. Mem. Inst. Butantan 1 (1): 1-37, Read more

July 10, 2016
Helicops hagmanni Roux 1910

Helicops hagmanni Roux 1910:439. Holotype: NMBA 6281, a 630 mm male (G. Hagmann). Type locality: Santarem, Brazil. Distribution: N Brazil (Pará etc.), Colombia ?, Venezuela (TF Amazonas), Peru. Original description. Roux, J. 1910. Eine neue Helicops-Art aus Brasilien. Zool. Anz. 36: 439-440 Read more

July 10, 2016
Helicops infrataeniatus Jan 1865

Helicops infrataeniatus Jan 1865: 253. Lectotype: ZMH – R04331 (formerly no. B88 da) The other syntype from Brazil is deposited in Essex Inst. Salem according to Jan (1865). Types: ZMH R04340-4 (5 specimens) type locality “Mexico” in error. The type specimens of Calopisma septemvittata are a species inquirenda (Smith & Taylor , 1945), and cannot allied… Read more

July 10, 2016
Helicops danieli Amaral 1938

Helicops danieli Amaral 1938: 232 Holotype: Instituto Butantan 9872, juvenile female. Type locality: Colombia, Santander, Carare. Original description. Amaral, A. D. 1938. Estudo sobre ophidios neotropicos 34. Novas notas sobre a fauna da Colombia e descripcao de uma especie nova de Colubrideo aglypho. Mem. Inst. Butantan 11 [1937]: 232-240 Read more

July 10, 2016

The most basal Thamnophiine clade recovered by Zaher et al. (2019) included the Liodytes, Clonophis, Haldea, and Virginia genera. These are a mixture of fossorial, terrestrial, and semi-aquatic species. Clonophis exploits an unusual aquatic habitat – crayfish burrows; both Haldea and Virginia are small fossorial species. Liodytes contain some of the most aquatic North American snakes.
The ancestor of North American natricids immigrated from Eurasia sometime before the early Miocene (~19–18 Ma). We know this because the earliest known Western Hemisphere natricid fossils date to the early Miocene, and we know they shared an ancestor because of shared anatomy and DNA.

There are no highly specialized aquatic pythons that converge with the anacondas – the highly aquatic boas. However, some python species are best considered semi-aquatic. The largest pythons (Malayopython reticulatus, Python sebae, Python natalensis, Python bivittatus) use aquatic situations to hunt and thermoregulate. The largest pythons are habitat generalists, but they are also frequently associated with water. The large body size may be possible because of their buoyance in water, making movement more efficient.

The highly aquatic and unique file snakes have loose, baggy skin and minor, rough scales, each with sensory organs. Their short tails are round, prehensile, flat, and sword-like; the eyes and valvular nostrils are dorsally or dorsolateral. Their lack of muscle tone is spectacular and can only be fully appreciated by handling one, a physiological feature restricting them to an entirely aquatic lifestyle. The rough, file-like surface of the skin and its loose folds are used in catching and holding slippery, mucus-covered fish. Their maxillary teeth are similar in size, long, and fluted on the sides and posterior surfaces. The fluted condition is found in many fish-eating snakes.

The two species that compose the genus Farancia are considered some of the most aquatic snakes in North America, but both species are known to wander overland (Steen et al. 2013). Droughts may trigger their movement from a wetland, and excessive rainfall may also trigger their movement. Females will also move overland to nest. Both species take aquatic prey. Semlitsch et al. (1988) have described juvenile emergence in both the Fall and Spring and note that hatchlings may benefit from Fall emergence by feeding before their first winter. However, Fall emergence may present the hatchlings with dried or reduced aquatic habitats, while spring emergence would have abundant habitat and food (larval salamanders).
The members of the genus are known to have maternal attendance of eggs, a highly specific diet of elongated prey, American eels (Anguilla rostrata), and the eel-like salamanders of the genera Siren and Amphiuma.

The largest boas, the highly aquatic anacondas (Eunectes), are relatively well known. The oldest and largest member of the clade (Titanoboa) was aquatic, and today, the most aquatic members of the family are the anacondas of the genus Eunectes.

Anacondas are Neotropical snakes found east of the Andes. Four extant species and one fossil species compose the genus. The clade includes the largest snake, the Green Anaconda, Eunectes murinus, which reaches at least 8 m and has the greatest mass (in females) of any extant snake (250 kg). Eunectes is derived from a Greek word that means “good swimmer.” The aquatic habitats of these snakes are well documented. Pizzatto et al. (2007) found an aquatic habitat to be a synapomorphy for this genus. The large body size, a relatively long tail, and the dorsal positioning of the eyes and nares are all traits associated with life in water.

Aquatic Snake Blog

Helicops carinicaudus (Wied-Neuwied 1825)

Helicops apiaka Kawashita-Ribeiro, Ávila & Morrais, 2013

Helicops gomesi Amaral 1921

Helicops hagmanni Roux 1910

Helicops infrataeniatus Jan 1865

Helicops danieli Amaral 1938