AUSTRALIAN BIODIVERSITY RECORD - Calodema

Australian Biodiversity Record, 2007 (8): 1-124to humans. Urgent medical attention should always be sought in the event of a bite from thisspecies, although there have been no known fatalities recorded.Survival Status: Protected under the Qld Nature Conservation Act (1992), the Territory Parksand Wildlife Conservation Act (1998) and the WA Wildlife Conservation Act 1950 (asamended). Listed as a Marine Protected Species under the Australian EnvironmentalProtection and Biodiversity Conservation Act (1999). Probably not under threat, but itsrestricted distribution in Australian waters could potentially make it vulnerable in some parts ofits range.Etymology: The name 'melanosoma' refers to the black bands on the body.Hydrophis vorisi Kharin, 1984Hydrophis vorisi Kharin, V.E. (1984): Zool. Zh. 63(4): 630-632. Type data: holotype AMNH58869. Type locality: eastern bank of Fly River, opposite Sturt Island, Western Province,Papua New Guinea.[Note: Previous records of this species in Australian waters were misidentifications of thesoutheast Asian species Hydrophis obscurus Daudin, 1803]Description: This is a medium-sized seasnake with a very small narrow head that is notdistinct from the neck, a very elongate forebody and a deep, compressed posterior body. Thebase body colour is pale greyish to whitish, with the head darker. There is prominenttransverse banding that encircles the entire body and tail, and there are usually no othermarkings within the pale interspaces along the body, with the exception of the extremeposterior portion where small blackish lines or flecking may be also present. The large series(70-80) of dark, almost black, crossbands are wider on the dorsum than the pale interspaces,but laterally, they taper somewhat to be about the same width as the paler interspaces. Insome specimens the dark bands are broken or interrupted along the vertebral line on thebody. The tail may have in addition to the banding pattern, scattered black marks within thepale interspaces. Some of the significant features of this species’ morphology are: headshields enlarged, symmetrical; parietal bone contacting the prefrontal; anterior part of maxillaarched upwards, the tip of the longer fang on a line connecting the tips of the solid maxillaries;6 maxillary teeth following fang; nasal separated from preocular by high 2nd supralabial; 3rdand 4th supralabials contacting orbit; mental groove present and distinct; mental triangular,broader than long, and not partially hidden in the shallow mental groove; anterior chin scaleslarge, and usually bordering mental groove; fewer than 25 body scale rows at neck; mid-bodyscales in 29-37 rows; body scales smooth and weakly imbricate anteriorly, but keeledposteriorly; ventrals 330-350, small, each about as wide as, or only slightly wider thanadjacent body scales, and never foliform; posterior ventrals distinct and mostly undivided.Attains a maximum total length of only around 0.6 m.Distribution: Known only from a relatively small part of Australia and New Guinea, centred onthe Torres Strait area of Queensland and adjacent parts of near coastal Papua New Guinea.Habitat: This species has been detected living mainly around coral reefs in shallowcontinental waters, but has also been recorded from inshore estuarine conditions as well.Biology/Ecology: This appears to be at least a partly diurnal species that feeds on a variety ofsmall fishes. Ovoviviparous.Toxicity: This is a small species that rarely attempts to bite under normal circumstances, butcaution should nevertheless be exerted, because its venom is likely toxic to humans. Urgentmedical attention should always be sought in the event of a bite from this species.Survival Status: Protected under the Qld Nature Conservation Act (1992). Listed as a MarineProtected Species under the Australian Environmental Protection and BiodiversityConservation Act (1999). Probably not under threat, but its restricted distribution in Australianwaters could potentially make it vulnerable in some parts of its range.41