Aipysurus foliosquama

Geographic Range

Aipysurus foliosquama (leaf-scaled seasnake) is endemic to the Ashmore Reef and the Hibernia Reef located in the Timor Sea off the Northwestern coast of Australia (Cousteau, 2008). Recently, a new population was discovered in Shark Bay (D’Anastasi et al., 2016). Several scattered reports exist of A. foliosquama being seen outside of these three locations, however it is believed that these individuals do not represent breeding populations (Cogger, 2000).

• Biogeographic Regions
• australian australian
  • native native
• oceanic islands oceanic islands
  • native native
• indian ocean
  • native native

Habitat

Aipysurus foliosquama prefers the shallow areas along the edges of reefs and has never been recorded at depths greater than 10 meters (Minton et al., 1975). A new, recently discovered population of leaf-scaled seasnakes was recently discovered to be living in the sea grass beds of Shark Bay in Australia (D’Anastasi, 2016).

• Habitat Regions
• tropical tropical
• saltwater or marine saltwater or marine

• Aquatic Biomes
• reef reef
• coastal coastal

• Other Habitat Features
• intertidal or littoral intertidal or littoral

Physical Description

Leaf-scaled seasnakes were named for the shape and pattern of their closely overlapping scales, which resemble leaves (Cousteau, 2008). These snakes are typically 60 to 90 centimeters long (Cogger, 2000; Heatwole 1999). The dorsal side is often dark reddish brown to purple, with lighter bands down the back (Cousteau, 2008). While males and females are similar in appearance, females often tend to be larger than their male counterparts (Cousteau, 2008).

• Other Physical Features
• ectothermic ectothermic
• heterothermic heterothermic
• bilateral symmetry bilateral symmetry
• venomous venomous

• Sexual Dimorphism
• female larger

Development

Leaf-scaled seasnakes are viviparous. Females give birth to small numbers of young at a time after a gestation period of approximately six months (Cousteau, 2008; Department of Sustainability, Environment, Water, Population and Communities, 2012). It takes up to two years for individuals to reach maturity and they have long life spans, 8 to 10 years (ICUN Red List, 2017).

Reproduction

There have been no published studies that describe the specific mating systems of A. foliosquama . Other sea snakes, in addition to most squamate reptiles, have been observed to be polygynandrous (Madsen et al., 2005). Fertilization is internal, and males have hemipenes which are used during mating. The male and female entwine during mating, which involves the snakes having to come to the surface for air multiple times. The female snake seems to determine when the mating pair takes breaths of air and when the mating process is concluded (Heatwole, 1999).

• Mating System
• polygynandrous (promiscuous) polygynandrous (promiscuous)

Leaf-scaled seasnakes are viviparous and give birth to small numbers of offspring at a time after a gestation period of approximately 6 to 7 months (Department of Sustainability, Environment, Water, Population and Communities, 2012). Due to the length of this interval, it is believed that Leaf-scaled Seasnakes may breed less frequently than once a year (Cogger, 2000; Department of the Environment, Water, Heritage and the Arts, 2006; Heatwole 1999).

• Key Reproductive Features
• iteroparous iteroparous
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• viviparous viviparous

There is little research to date on the parental investment of A. foliosquama specifically, however most sea snakes (and reptiles in general) produce highly precocial young and it can be assumed that this is true of the Leaf-scaled Seasnake as well (Voris and Jayne, 1979). Females certainly provision their young by yolking eggs, and may also provision growing embryos with bodily nutrients as well, though this needs further study (Heatwole 1999).

• Parental Investment
• pre-fertilization
  • provisioning
  • protecting
    • female
• pre-hatching/birth
  • provisioning
    • female

Lifespan/Longevity

A. foliosquama has a presumed life span of approximately 8 to 10 years. This long life span is believed to compensate for the long time that it takes for these snakes to reach sexual maturity, at roughly 2 years (ICUN Red List, 2017).

Behavior

The three known populations of A. foliosquama are believed to represent three largely isolated breeding populations separated by open ocean waters that are difficult for individuals to cross (ICUN Red List, 2017). Leaf-scaled sea snakes are solitary creatures with the exception of mating and occasional sightings of small groups (Guinea and Whiting 2005).

• Key Behaviors
• natatorial natatorial
• motile motile
• solitary solitary

Home Range

There is apparently no specific published information to date on the home range or territorial inclinations of individual Leaf-scaled Seasnakes.

Communication and Perception

There is little information available on communication in leaf-scaled seasnakes. They are a solitary species (Guinea and Whiting 2005). Little specific information exists on how this species perceives its environment but in other species of sea snake, vision is important (Hibbard and Lavergne, 1972). In addition, sensing water vibrations probably plays a key role in their marine environment (Westhoff et al. 2005), and the vomeronasal organ (sensing chemical "odors" and supplied by the tongue) is undoubtedly important to these snakes, as it is other snakes.

• Communication Channels
• visual visual
• tactile tactile
• chemical chemical

• Other Communication Modes
• pheromones pheromones
• vibrations vibrations

• Perception Channels
• visual visual
• tactile tactile
• vibrations vibrations
• chemical chemical

Food Habits

Leaf-scaled seasnakes feed primarily on shallow reef dwelling fish such as Halichoeres species and Eleotridae . In addition, they eat certain types of eels ( Anguilliformes ) which are found in the same shallow, reef habitats (Department of Sustainability, Environment, Water, Population and Communities, 2012). Leaf-scaled seasnakes find prey by sticking their head into holes and crevices in coral reefs. They then bite and immobilize prey through envenomation (McCosker 1975).

• Primary Diet
• carnivore carnivore
  • piscivore piscivore

• Animal Foods
• fish

Predation

The predators of A. foliosquama have not been described in the literature.

Ecosystem Roles

Leaf-scaled seasnakes are top predators and may play a role in the population control of the species that it eats, such as small fish and eels (McCosker 1975). Occasionally algae and barnacles use this snake as a host. To prevent this, leaf-scaled seasnakes shed their skin frequently, approximately once every 2 to 6 weeks (Department of Sustainability, Environment, Water, Population and Communities, 2012).

Economic Importance for Humans: Positive

Leaf-scaled seasnakes may play a role in controlling the populations of various reef fishes and eels that it eats, although the types of fish that these snakes eat are generally of little or no commercial importance to people (Department of Sustainability, Environment, Water, Population and Communities, 2012).

Economic Importance for Humans: Negative

The venom of A. foliosquama is potentially fatal to humans. Reported instances of envenomation are apparently rare (Cogger, 2000; Heatwole, 1999).

• Negative Impacts
• injures humans
  • venomous venomous

Conservation Status

Leaf-scaled seasnakes are listed as critically endangered (ICUN Red List, 2017).

Additional Links

Encyclopedia of Life

Contributors

Molly Schools (author), Michigan State University, James Harding (editor), Michigan State University, Tanya Dewey (editor), University of Michigan-Ann Arbor.

References

Cogger, H. 2000. Reptiles and Amphibians of Australia . Sanibel: Ralph Curtis Books.

Cousteau, F. 2008. Ocean . London: Penguin.

D'Anastasi, B., L. Van Herwerden, J. Hobbs, C. Simpfendorfer, V. Lukoschek. 2016.

New range and habitat records for threatened Australian sea snakes raise challenges for conservation

Guinea, M., S. Whiting. 2005. Insights into the distribution and abundance of sea snakes at Ashmore Reef. The Beagle , 1: 199-206.

Heatwole, H. 1999. Sea Snakes . Malabar, FL: Krieger Publishing Company.

Hibbard, E., J. Lavergne. 1972. Morphology of the retina of the sea-snake, Pelamis platurus . Journal of anatomy , 112: 125.

Madsen, T., B. Ujvari, M. Olsson, R. Shine. 2005. Paternal alleles enhance female reproductive success in tropical pythons. Molecular Ecology , 14: 1783-1787.

McCosker, J. 1975. Feeding behavior of Indo-Australian hydrophiidae. The biology of sea snakes , 1: 217-232.

Minton, S., H. Heatwole, W. Dunson. 1975. Sea snakes from reefs of the Sahul Shelf. University of Maryland Press , 1: 141-144.

Voris, H., B. Jayne. 1979. Growth, reproduction and population structure of a marine snake, Enhydrina schistosa (Hydrophiidae). Copeia , 2: 307-318.

Westhoff, G., B. Fry, H. Bleckmann. 2005. Sea snakes ( Lapemis curtus ) are sensitive to low-amplitude water motions. Zoology , 108: 195-200.

Department of the Environment and Water Resources, Canberra

Final Report Survey 2005: Sea snakes of Ashmore Reef, Hibernia Reef and Cartier Island

2014. " Aipysurus foliosquama SMITH, 1926" (On-line). Reptile Database. Accessed December 03, 2017 at http://reptile-database.reptarium.cz/species?genus=Aipysurus&species=foliosquama .

Australian Government-Department of the Environment and Energy. Aipysurus foliosquama — Leaf-scaled Seasnake. Canberra: Department of Sustainability, Environment, Water, Population and Communities. 2012.

2017. "ICUN Red List" (On-line). Accessed December 03, 2017 at http://www.iucnredlist.org/details/176714/0 .