AUSTRALIAN BIODIVERSITY RECORD - Calodema

Australian Biodiversity Record, 2007 (8): 1-124Disteira major (Shaw, 1802)Hydrus major Shaw, G. (1802): General Zoology, or Systematic Natural History. [p. 558, pl.124] [Note: other syntype, BMNH iii.9.1.a, referred to Astrotia stokesii]. Type data: lectotypeBMNH 1946.1.9.24. Subsequent designation: Cogger, H.G. (1983): Zool. Cat. Aust., 1.Amphibia and Reptilia. [see p. 246]. Type locality: Indian Ocean (as Indian Seas).Disteira doliata Lacépède, B.G.E. (1804): Ann. Mus. Natl Hist. Nat. Paris 4: 184-211 [199,210, pl. 57 fig. 2]. Type data: type status unknown (presumed lost). Type locality: Australia.Pelamis shavii Merrem, B. (1820): Tentamen Systematis Amphibiorum. [p. 139] [unnecessaryreplacement name for Hydrus major Shaw, 1802].Hydrophis mentalis Gray, J.E. (1842): Monographic Synopsis Water Snakes Hydridae. [p. 62].Type data: holotype BMNH 1946.1.9.24. Type locality: Indian Ocean.Disteira dumerilii Jan, G. (1859): Rev. Mag. Zool. (2)11: 148-157 [p. 149]. Type data: holotypeMNHP 7705. Type locality: Australia.Hydrophis lacepedei Jan, G. (1859) : Prodr. Iconogr. Ophidiens..Rev. Mag. Zool. (2)10 and(2)11-12, 1858 and 1859. [pl. D] [lapsus for Disteira dumerilii Jan, 1858]Distira nasalis De Vis, C.W. (1905): Ann. Qd Mus. 6: 46-52 pl. 15 [p. 48]. Type data: holotypeQM J203. Type locality: QLD coast.Description: This is a more robust-bodied species of sea snake than D. kingii, with a shortdeep head that is barely distinct from the neck. The base body colour is pale greyish-white toolive green, with the head tending to be a shade of olive green or olive-brown, with scattereddarker flecks. The body is boldly marked with a series of around 25-30 large broad darkbrown to black blotches or saddles across the body, each separated by a slightly wider paleinterspace. The large saddle-like blotches extend to about mid-way down the side of thebody. The lower lateral area is creamish-yellow. Within each pale interspace there is a thin(about 1 scale wide) black transverse ‘band’ in the centre, and each ‘band’ extends down thebody to about the mid-lateral area. This pattern forms a double banded appearance withalternating thick and thin dark blotches or bands along the body. In some the lower flanksmay be dark blotched as well, and these large lower blotches are below both the thininterspace bands and the dorsal saddle-like blotches. The overall pattern tends to be moreconspicuous in immatures and less defined in mature individuals. Ventrally, most specimensare dark grey, but some may have dark flecking on the ventrals as well. Some significantfeatures of this species’ morphology are: head shields large and symmetrical; 7-8 (rarely 9)maxillary teeth following fang; supralabials 7-8; preocular present; postoculars 1-2 (usually 2);prefrontal in contact with second supralabial; primary temporals usually 2; anterior chinshields barely contacting mental groove (usually prevented from contact by elongate firstinfralabial); body scales imbricate and bluntly keeled dorsally, but smooth laterally; bodyscales around neck 30-36; mid-body scales in about 33-45 rows; ventrals with two keels;ventrals around about 195-265, small, bicarinate, and only slightly larger than adjacent bodyscales; anal scales enlarged; Attains a maximum total length of around 1.6 m although anaverage adult would be around 1.4 m., and females tend to be somewhat longer than males.Females are sexually mature at 0.7m snout-vent length.Distribution: Largely confined to tropical Australian and New Guinean seas, being foundmainly off the coasts of New Guinea, Queensland, Northern Territory and Western Australia,usually to about Shark Bay, but rarely as far south as Bunbury. Also reaches New Caledonia.Rare sightings may occur in New South Wales waters as well.Habitat: Commonly found in deep (to about 22 metres) turbid waters in the vicinity of muddyor sandy river deltas, including relatively shallow tropical tidal rivers and creeks, as well as ingulf waters and deeper continental shelf waters.32