AUSTRALIAN BIODIVERSITY RECORD - Calodema

Australian Biodiversity Record, 2007 (8): 1-124grey dorsally and whitish ventrally, although the ventral area of the neck may be blackish;mid-laterally, there is a zone where the darker upper, and paler lower body base colourationssmoothly merge. Patterning in adults is confined to a series (about 50-70) of dark - almostblack - transverse bands on the body, and these are broadest and darkest vertebrally (wherethey create a wide blotched pattern to the dorsum). The body bands gradually narrow andfade laterally to form continuous greyish banding to the ventrals. Sometimes the body bandsmay be split or completely separated at the vertebral line, and the banding of the neck iscontinuous with the black ventrals. The dark banding of adults tends to be also more intenseanteriorly, often with secondary bands or blotches between the main bands. The tail is oftendark with banding less pronounced, with the tip greyish, and this is a paler colour than thedarker cross-bands, when bands are present on the tail. The dorsum of the head is dark greyfleckedwith pale whitish flecks. The juvenile or immature pattern is much more pronounced,with distinctive black bands encircling the body; the anterior of the venter is black. The headand throat of juveniles is black, with pale flecking or tiny spotting on the snout, and there is ayellowish spot on each temporal area (just behind each eye). Some significant features of thisspecies’ morphology are: head shields enlarged, symmetrical; anterior part of maxilla notarched upwards, the tip of the fang projecting conspicuously below a line connecting the tipsof the solid maxillaries; 5-8 maxillary teeth following fang; nasal separated from preocular byhigh 2nd supralabial; usually the 3rd, 4th, and 5th supralabials contacting orbit; mental groovepresent and distinct; mental triangular, broader than long, and not partially hidden in theshallow mental groove; anterior chin scales large, and usually bordering mental groove; bodyscales imbricate, in 39-49 rows at mid.body; posterior ventrals distinct, mostly undivided;ventrals 320-430, small, about as wide as, or only slightly wider than adjacent body scalesand never foliform. Attains a maximum total length of around 1.5m.Distribution: Known from tropical Australian and New Guinea seas, being mainly found in theGulf of Carpentaria and Torres Strait in Queensland and the Arafura Sea near the NorthernTerritory.Habitat: This species lives mainly around coral reefs, but also found in muddy waters of riverdeltas, bays, estuaries and gulfs on continental shelf areas.Biology/Ecology: This is a fast-swimming, diurnal species, which feeds on a variety of smallfishes. Very little has been recorded on the reproductive biology of this species, oviducaldevelopment occurs in the Dry Season, so it likely that the young are born during or followingthe Wet Season. A gravid female carrying 17 developing young has been reported.Toxicity: This species rarely attempts to bite under normal circumstances, but caution shouldnevertheless be exerted, because its venom is highly toxic to humans. Urgent medicalattention should always be sought in the event of a bite from this species.Survival Status: Protected under the Qld Nature Conservation Act (1992) and the TerritoryParks and Wildlife Conservation Act (1998). Listed as a Marine Protected Species under theAustralian Environmental Protection and Biodiversity Conservation Act (1999). Probably notunder threat, but its restricted distribution in Australian waters could potentially make itvulnerable in some parts of its range.Etymology: The name ‘pacifica’ probably refers to the Pacific geographic area, but this wouldbe somewhat of a misnomer as this species is only known from the edge of the region.Genus Microcephalophis Lesson, 1834Microcephalophis Lesson, R.P. (1834). Reptiles. [Pp. 289-336]. In: Bélanger, C. (Editor):Voyage aux Indes-Orientales, par le Nord de l'Europe pendant les Années 1825, 1826, 1827,1828 et 1829. Paris: Arthus Bertrand xxxix 535 pp. [p. 320] [?non Hydrus gracilis Shaw,1802]. Type species: Microcephalophis gracilis Lesson, 1834 by monotypy. AlthoughMicrocephalophis was based on illustrations in Russell (1801), none refer to Hydrus gracilis ofShaw (1802). The determination of the Type Species was done by Smith (1926), and laterfollowed by McDowell (1972) [see Cogger (1983): Zool. Cat. Aust., 1 Amphibia Reptilia]45