Hydrophis semperi

Hydrophis semperi
Conservation status
	; Vulnerable (IUCN 3.1)
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Squamata
Suborder:	Serpentes
Family:	Elapidae
Genus:	Hydrophis
Species:	H. semperi
Binomial name
	Hydrophis semperi; Garman, 1881
Synonyms
	Distira semperi; — Boulenger, 1896; Leioselasma semperi; — Kharin, 1984; Hydrophis semperi; — Sanders et al., 2012;

Last updated August 16, 2023

Hydrophis semperi, commonly known as the Lake Taal snake,^[1]^[2]Garman's sea snake,^[3] the Philippine freshwater sea snake,^[4] and the Luzon sea snake,^[5] is a rare species of venomous sea snake found only in a single lake on the island of Luzon in the Philippines.^[1]^[4] It is noted for being one of two known species of sea snakes that are known to be found almost-exclusively in freshwater.^[2]^[6] The other freshwater sea snake species is Laticauda crockeri.^[2]

Etymology

H. semperi was named after Carl Semper, a German ecologist who discovered the species in the mid-19th century.^[3] Locally, the snake is known as duhol matapang.^[5]^[6]

Taxonomy

H. semperi is classified with the rest of the "true" sea snakes in the subfamily Hydrophiinae of the family Elapidae.^[2]^[7]^[8]

Description

Like all "true" sea snakes, H. semperi is a rather heavyset snake, elongated with a small head. It possesses the characteristic flattened, paddle-like tail found in the members of its subfamily. This particular species is considered short in comparison to the rest of the family; adult specimens of H. semperi that have been caught have a total length (including tail) of 50 to 70 cm (20 to 28 in). The snake is colored much like a typical sea snake, having a dark blue or black body with narrow yellow (sometimes white) crossbands. Like its close relatives, its nostrils are located almost dorsally, with valves that prevent water from entering its nasal (and oral) cavities when the snake is submerged.^[9]

Habitat and evolution

H. semperi is known to be found only in the waters of Lake Taal (formerly known as Lake Bombon) in the province of Batangas in the Philippines. The only freshwater sea snake in the country, it lives the entirety of its life within the confines of the lake, feeding and breeding in its slightly acidic waters. The lake itself is a volcanic crater lake, which was formerly saltwater but gradually lost its salinity after the lake was closed off from the sea by an eruption in the 16th century. It is this unique aspect of the lake's formation and history that led to the evolution of several once-saltwater species, including H. semperi. Thus, this species is relatively young, having been accustomed to freshwater for less than a millennium.

Diet

As with "true" sea snakes, H. semperi is piscivorous, feeding primarily on the numerous fish species that are known to dwell in Taal Lake's murky waters.

Biology

Very little is known about the life history of H. semperi, including its ecology and breeding cycles.

Conservation status

Since so little is known about the reproductive habits of the species H. semperi, there have been virtually no estimates of the snake's population. Like many other species endemic to the lake, it is vulnerable as a species to any anthropogenic effects on the lake's ecosystem, both direct and indirect. Pollution is always a major issue when it comes to enclosed bodies of water with numerous surrounding human settlements. The numerous commercial establishments, towns and plantations dumping chemicals and sewage into the lake, combined with the dense population of fish farms in the lake's waters may yet have an adverse effect on the health of the species as a whole. In addition, while the snake itself has no commercial value and is not harvested, it suffers from the typical human stigma that is often attributed to snakes. Fishermen that frequently encounter the docile snakes have been known to kill them simply because of what they are.^[6]

Related Research Articles

Elapidae is a family of snakes characterized by their permanently erect fangs at the front of the mouth. Most elapids are venomous, with the exception of the genus Emydocephalus. Many members of this family exhibit a threat display of rearing upwards while spreading out a neck flap. Elapids are endemic to tropical and subtropical regions around the world, with terrestrial forms in Asia, Australia, Africa, and the Americas and marine forms in the Pacific and Indian Oceans. Members of the family have a wide range of sizes, from the 18 cm (7.1 in) white-lipped snake to the 5.85 m king cobra. Most species have neurotoxic venom that is channeled by their hollow fangs, and some may contain other toxic components in various proportions. The family includes 55 genera with some 360 species and over 170 subspecies.

Hydrophiinae is a subfamily of venomous snakes in the family Elapidae. It contains most sea snakes and many genera of venomous land snakes found in Australasia, such as the taipans (Oxyuranus), tiger snakes (Notechis), brown snakes (Pseudonaja) and death adders (Acanthophis).

Taal Lake, formerly known as Bombón Lake, is a freshwater caldera lake in the province of Batangas, on the island of Luzon in the Philippines. The lake fills Taal Volcano, a large volcanic caldera formed by very large eruptions between 500,000 and 100,000 years ago.

Hydrophis nigrocinctus is a species of marine venomous snakes in the family Elapidae.

Hydrophis brookii is a species of venomous sea snake in the subfamily Hydrophiinae of the family Elapidae. The species is native to bodies of water in Southeast Asia.

Hydrophis cyanocinctus, commonly called the annulated sea snake or the blue-banded sea snake, is a species of venomous sea snake in the family Elapidae.

Hydrophis fasciatus, commonly known as the striped sea snake, is a species of venomous sea snake in the family Elapidae (Hydrophiinae).

Hydrophis spiralis, commonly known as the yellow sea snake, is a species of venomous sea snake in the family Elapidae.

Hydrophis annandalei, commonly known as Annandale's sea snake or the bighead sea snake, is a species of venomous snake in the subfamily Hydrophiinae of the family Elapidae. The species, which is sometimes placed in its own genus Kolpophis, is native to parts of the Indian Ocean.

Hydrophis curtus, also known as Shaw's Sea Snake, short sea snake, but often includes Hydrophis hardwickii is a species of sea snake. Like most Hydrophiinae sea snakes, it is a viviparous, fully marine, and front fanged elapid that is highly venomous. It is collected for a variety of purposes including human and animal food, for medicinal purposes and for their skin.

Hydrophis viperinus, commonly known as the viperine sea snake, is a species of venomous sea snake in the family Elapidae (Hydrophiinae).

Sea snakes, or coral reef snakes, are elapid snakes that inhabit marine environments for most or all of their lives. They belong to two subfamilies, Hydrophiinae and Laticaudinae. Hydrophiinae also includes Australasian terrestrial snakes, whereas Laticaudinae only includes the sea kraits (Laticauda), of which three species are found exclusively in freshwater. If these three freshwater species are excluded, there are 69 species of sea snakes divided between seven genera.

Hydrophis is a genus of sea snakes, venomous snakes in the subfamily Hydrophiinae of the family Elapidae. Species in the genus Hydrophis are typically found in Indo-Australian and Southeast Asian waters. Currently, around 36 species are recognized as being valid.

Hydrophis peronii, commonly known as the horned sea snake, Peron's sea snake, and the spiny-headed seasnake, is a species of venomous snake in the subfamily Hydrophiinae of the family Elapidae. The species is endemic to the western tropical Pacific Ocean. It is the only sea snake with spines on the head. It is sometimes placed in its own genus Acalyptophis.

The yellow-bellied sea snake is a venomous species of snake from the subfamily Hydrophiinae found in tropical oceanic waters around the world except for the Atlantic Ocean. For many years, it was placed in the monotypic genus Pelamis, but recent molecular evidence indicates it lies within the genus Hydrophis.

Hydrophis donaldi, or the rough-scaled sea snake is a unique species of sea snake from Australia's Gulf of Carpentaria first described in 2012. It is a yellow to brown, striped snake that reaches up to a meter in length. It gives live birth and is venomous enough to be dangerous to humans. The primary distinguishing trait of the rough-scaled sea snake is the presence of a single spine on every scale covering the snake's body. The snake's tough, spiny scales may protect it from being buffeted against the rocks of its stony estuary habitats by the action of the waves and currents. Other less spectacular traits distinguishing it from other members of the genus Hydrophis include the lack of a groove running through the scales underlying its abdomen, a larger and rounder skull, differing numbers of scales around the circumference of different bodily regions, and a larger number of stripes than many sea snakes have.

Enhydrina zweifeli is a species of snakes found from New Guinea to Australia. In the past they were thought to be Enhydrina schistosa, but after DNA testing are now provisionally identified as Enhydrina zweifeli. DNA test have shown they are not related to Enhydrina schistosa.

Vladimir Yemelyanovich Kharin (1957–2013) was a Russian zoologist, ichthyologist, herpetologist, and a specialist in sea snakes.

The slender-necked sea snake, also known commonly as Cogger's sea snake, is a species of marine venomous snake in the subfamily Hydrophiinae of the family Elapidae. The species is native to waters around western Australia and the southern Pacific Ocean.

Hydrophis czeblukovi, also known commonly as the fine-spined sea snake, the geometrical sea snake, and the geometrical seasnake, is species of venomous snake in the subfamily Hydrophiinae of the family Elapidae. The species is native to waters off northern Australia.

References

1 2 3 Gatus, J. (2010). "Hydrophis semperi". IUCN Red List of Threatened Species . 2010: e.T176747A7296443. doi: 10.2305/IUCN.UK.2010-4.RLTS.T176747A7296443.en . Retrieved 20 November 2021.
1 2 3 4 5 Hydrophis semperi at the Reptarium.cz Reptile Database. Accessed 9 April 2019.
1 2 "Hydrophis semperi ". UNEP-WCMC Species Database. United Nations Environment Programme. Archived from the original on 2007-09-30. Retrieved 2007-02-02.
1 2 "Philippine freshwater sea snake/Garman's sea snake". Snakes in the Philippines. Retrieved 9 April 2019.
1 2 Beolens, Bo; Michael Watkins; Michael Grayson (2011). The Eponym Dictionary of Reptiles. Baltimore: Johns Hopkins University Press. xiii + 296 pp. ISBN 978-1-4214-0135-5. (Hydrophis semperi, p. 240).
1 2 3 Diesmos, Arvin C. [in French]; Rafe M. Brown [in French]; Marefe C. Lagda; Norydel F. Tresnado (2005-03-07). "The "sea" snake of Taal Lake". Features. Haribon Foundation for the Conservation of Natural Resources. Archived from the original on 2 March 2007. Retrieved 2007-02-02.
↑ "Hydrophis semperi ". Integrated Taxonomic Information System . Retrieved 13 January 2007.
↑ Bischoff, Joe; Mikhail Domrachev; Scott Federhen; Carol Hotton; Detlef Leipe; Vladimir Soussov; Richard Sternberg; Sean Turner. "Hydrophis semperi ". National Center for Biotechnology Information Database. U.S. Library of Medicine. Retrieved 2007-02-02.
↑ Uetz,Peter. EMBL Reptile Database: Subfamily Hydrophiinae (Sea Snakes). Family Elapidae (cobras, coral snakes, and seasnakes etc.). European Molecular Biology Laboratory (EMBL) Heidelberg 2006-04-04