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Isotriphora tasmanica (Tension-Woods, 1876)

Description: Shell variable in size, sinistral. Protoconch relatively large, lecithotrophic, of about 2 whorls, with 2 strongly nodulose spiral cords. Teleoconch whorls with 4 beaded spiral cords and axial costae; spirals 1 and 3 start immediately after protoconch, spiral 2 after 1 or 2 whorls. Spirals 1-3 attain similar size by penultimate whorl. Spiral 4 a fine rib exposed on all whorls. Another 2 spirals on base (numbered 5 and 6), smooth, spiral 6 faint. Axial costae number 19-30 on penultimate whorl. Outer lip of aperture flared, anterior siphonal canal upturned, posterior canal a simple wide notch. Colour yellowish brown with reddish brown between nodules on spiral 3 (on rare fresh specimens); beach specimens uniformly orange brown.

Size: Adult shells 5.5 - 10.8 mm in length. .

Distribution: Endemic to Australia: Angourie, NSW, southwards and around southern Australia, to Eyre Peninsula, SA, including Tasmania.

Habitat: Subtidal, down to 200 m, with one record of 549 m. Moderately common. Very rarely known from beach washup.

Comparison: This species has a distinctive protoconch with strongly nodulose spiral cords.

Synonymy: Isotriphora echina Laseron, 1954 is a previously recognised synonym

Figs. 1, 2: Off Lakes Entrance, Victoria (C.113423)

 

Copyright Des Beechey 2015