Aquatic Snake Blog

Helicops modestus Günther 1861

Helicops modestus Günther 1861: 425. Holotype BMNH 1946.1.14.42. Type locality. Tropical America? Tachyplotus hedemanni Reinhardt 1866 Helicops assimilis Reinhardt 1866: 156. Type locality. Minas Gerais, Brazil. Distribution. Brazil: Minas Gerais, Distrito Federal, Goias, Bahia. Original description. Günther, A. 1861. On the ophidian genus Helicops. Ann. Mag. Nat. Hist. (3) 7: 425-428. Read more

July 10, 2016
Helicops leopardina Schlegel 1837

Homalopsis leopardina Schlegel 1837: 358. Holotype. ? Type locality: unknown Helicops leprieurii Dumeril Bibron & Duméril 1854 750 Helicops leprieurii – Günther 1861: 427 Helicops leopardinus – January 1865 Distribution. Guiana, Suriname, French Guiana, Brazil, Bolivia, Paraguay, northern Argentina,? Colombia? Ecuador, Peru. Original description Schlegel, H. 1837. Essay on the faces of serpents. General section: xxviii + 251 S.… Read more

July 10, 2016
Sea snakes anticipate tropical cyclone.

Abstract Here, we report anticipatory behaviors of sea snakes and provide the first evidence for a sensory mechanism by which they survive a catastrophic cyclone. Sea kraits (Laticauda spp.) are normally abundant in littoral habitats at Lanyu (Orchid Island), Taiwan but disappeared coincident with falling barometric pressure prior to typhoon Morakot, which impacted the island severely during… Read more

July 10, 2016
Brachyorrhos wallacei

Brachyorrhos wallacei Murphy, Mumpuni, de Lang, Gower, and Sanders, 2012a: 510. Holotype: BJE0 1059. Type locality: Jailolo, Halmahera, Indonesia. Brachyorrhos albus – Boulenger, 1893, 1: 305. Distribution: Halmahera, Indonesia (Murphy et al. 2012a). Diagnosis: A fangless homalopsid. Usually lacks preocular, usually seven (rarely six) upper labials, tallest is sixth (rarely fifth). This snake is quite similar to B. raffrayi… Read more

March 29, 2016
Raclitia indica Gray 1842

Raclitia indica Gray 1842 Zoological Miscellany, p. 67. Type locality: Malay Peninsula. Syntypes: BMNH 1946.1.2.36, 1946.1.2.46. Hypsirhina indica – Boulenger, 1896 Catalogue of Snakes in the British Museum.3:4. Enhydris indica – Tweedie, 1957 Snakes of Malaya, p. 89. Diagnosis: A snake with seven upper labials, one postocular, and 19 scale rows on the neck and mid-body, which are… Read more

March 29, 2016
Cerberus schneiderii Schlegel, 1837

Elaps boaeformis Schneider, 1801, 2: 301. Homalopsis molurus: Boie, 1826: 213. Python boaeformis: Merrem, 1820: 89. Homalopsis schneiderii Schlegel, 1837: 341. Homalopsis rhinchops: Cantor, 1847: 91. Cerberus acutus Gray, 1849: 65. Holotype: BMNH 1946.1.2.34. Type Locality: Borneo. Cerberus unicolor Gray, 1849: 65. Holotype: BMNH 1946.1.2.45. Type Locality: Philippines. Cerberus rynchops: Bleeker, 1857a: 233. Cerberus boaeformis: Bleeker, 1857b: 238. Hurria… Read more

March 29, 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 modestus Günther 1861

Helicops leopardina Schlegel 1837

Sea snakes anticipate tropical cyclone.

Brachyorrhos wallacei

Raclitia indica Gray 1842

Cerberus schneiderii Schlegel, 1837