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Mesoginella strangei (Angas, 1877) Diagnosis: Shell small, white, somewhat narrowed anteriorly; spire low to medium height; aperture moderately narrow, widening anteriorly; lip smooth or denticulate, moderately to strongly thickened internally, thickest centrally, not thickened in posterior quarter; external varix present; siphonal notch absent; posterior notch weak; ventral callus absent; columella with four strong plaits occupying about half the aperture, 4th fold remote. Size: Adults 2.5–3.5 mm in length. Distribution: Australian Museum Collection: off Manning River, NSW, to south-western WA, including Tasmania. Moderately common in 7-457 metres, occasionally recorded as a beach shell. Comparison: This species is similar in shape to M. inconspicua, but is smaller. A useful identification feature of mature shells is the shape of the lip - much thickened centrally, but not in the posterior quarter. (See Identification of beach specimens) Synonymy: The typical form is shown in Fig. 1a. Laseron described three new species which are forms of this species. Marginella sinuata Laseron, 1948 (Fig. 1b) is based on a type lot of mature shells with the sinuate lip typical of the species (NEW SYNONYM). Marginella frequens Laseron, 1948 (Fig. 2a) and Marginella pipere Laseron, 1948 (Fig. 2b) are both based on type lots that are juvenile, without the adult thickened lip, and are more elongate than the typical form (NEW SYNONYMS). Fig.1a: Off Nelson Head, NSW (C.070620) Fig 1b: Syntype of Marginella sinuata Laseron, 1948; off Point Halliday, NSW (C.103359) Fig. 2a: Syntype of Marginella frequens Laseron, 1948; off Sydney (C.103372) Fig. 2b: Syntype of Marginella pipere Laseron, 1948; off Twofold Bay, NSW (C.103370) |
