Shaw's Sea Snake

Hydrophis curtus, also known as Shaw's Sea Snake, short sea snake, but often includes Hydrophis hardwickii^[2] 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.^[3] It is collected for a variety of purposes including human and animal food, for medicinal purposes and for their skin.^[4]

Description

This species is characterized by a wide variation in number of ventral scales and degree of parietal scale fragmentation.^[2] Both sexes possess spiny scales along their bodies but males have more highly developed spines. This sexual dimorphism in spines may play a role in courtship or in locomotion by reducing drag.^[2]

Distribution

It is a widely distributed species and like most sea snakes is restricted to warmer, tropical waters. Its range includes:

• Persian Gulf (Oman, Bahrain, United Arab Emirates, Iran)
• Indian Ocean (Bangladesh, Pakistan, Sri Lanka, India)
• South China Sea (north to the coasts of Fujian and Shandong)
• Strait of Taiwan
• Indo-Australian Archipelago
• North Coast of Australia (Northern Territory, Queensland, Western Australia)
• Philippines (Panay)
• Pacific Ocean (Myanmar, Thailand, Indonesia, China, Japan, New Guinea)
• Andaman & Nicobar Islands, Cambodia and Singapore ^[1]

Taxonomy

Originally considered to be two species of the genus Hydrophis: Hydrophis curtus and Hydrophis hardwickii. Gritis and Voris (1990) examined the morphological variation of over 1,400 specimens across its geographic range and concluded it is most likely a single species.^[2][4] As is convention, the species name reverts to the first description by Shaw in 1802. DNA and morphological analysis restored its phylogenic status as a single species.^[5] An analysis of the population in 2014 found strong evidence of deep divergence and genetic isolation across the geographical range, supporting a division of the species to Indian Ocean and West Pacific groups and high likelihood of cryptic taxa within those groups.^[6]

Hydrodynamic sense

They have corpuscles (scale sensillae) concentrated on the front of their head which may be a hydrodynamic receptor.^[7] A study measuring brain response to water vibration found that L. curtus is sensitive to low amplitude (100–150 Hz) water motions.^[8] Sensing water motion is useful in locating prey, predators, or potential mates and has been demonstrated in other aquatic animals (e.g. lateral line in fish, whiskers in harbour seals).^[9]

References

Notes

Sources

• Anderson, J. 1871 A list of the reptilian accession to the Indian Museum, Calcutta, from 1865 to 1870, with a description of some new species. J. Asiat. Soc. Bengal, Calcutta, 40, part 11(1): 12–39.
• Rasmussen, A. R. & I. Ineich 2000 Sea snakes of New Caledonia and surrounding waters (Serpentes: Elapidae): first report on the occurrence of Lapemis curtus and description of new species from the genus Hydrophis. Hamadryad, 25(2): 91–99.