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TRIPHORIDAE


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Monophorus nigrofuscus (A. Adams, 1854)

Description: Shell medium-sized, sinistral. Protoconch lecithotrophic, of 2-2 whorls, with 2 spiral threads and numerous axial riblets. Teleoconch whorls convex with 4 beaded spiral cords and axial costae; spirals 1-4 commence immediately after protoconch; spiral 4 entirely exposed on all whorls. Another 2 spiral ribs on base (numbered 5 and 6). Spirals 1-3 of similar size on penultimate whorl. Axial costae of similar strength to spirals, nodulose at intersections, 18-24 on penultimate whorl. Outer lip of aperture flared, anterior siphonal canal slightly upturned, posterior canal a broad triangular notch. Protoconch and earliest teleoconch whorls fawn or white; subsequent whorls either buff-white or reddish to yellowish brown, or maculated; base darker.

Size: Mature specimens 4.5 - 13.3 mm in length.

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

Habitat: Living specimens are known from the intertidal zone on rocky shores. Empty shells are know from beach washup down to about 150 m. Common.

Comparison: This is much more common than most of the NSW triphorids, and is distinguished by having all of the spiral cords starting together immediately after the protoconch.

Synonymy: Triphora cinerea Hedley, 1903 is a synonym.

Remarks: This species varies widely in number of whorls at maturity (9-17) and in shell length (15.5-13.3 mm), as reported by Marshall (1983, p. 28).

Figs. 1, 2: Long Reef, Collaroy, NSW (C.064078)

Fig. 3:  From Hedley, 1903, pl. 33, fig.35

 

Copyright Des Beechey 2015