Perrinia

Herbert, D. G., 2012, A revision of the Chilodontidae (Gastropoda: Vetigastropoda: Seguenzioidea) of southern Africa and the south-western Indian Ocean, African Invertebrates 53 (2), pp. 381-381 : 464-465

Genus Perrinia H. & A. Adams, 1854

Perrinia : H. & A. Adams 1854 in 1853–54: 419. Type species: Monodonta angulifera A. Adams, 1853 , by subsequent designation (Pilsbry 1890 in 1889–90: 15).

Shells of Perrinia species are small (length <20 mm) with relatively flat-sided whorls, resulting in a trochiform spire. The suture is frequently strongly indented and the periphery often angular and/or keeled. The apical whorls are sculptured only with axial pliculae and subsequent whorls with both spiral cords and axial pliculae that interact to produce a cancellate or foveolate sculpture (not obviously beaded). The columella has a single, relatively weak tooth or knob near its base, there is no inductural callus shield, the umbilicus is generally closed, and the interior of the outer lip bears spiral ridges that extend deep into the aperture. The juvenile microsculpture is granular and lacks vermiform spiral threads, and the adult microsculpture of close-set, scratch-like, axial marks is well developed.

Perrinia has long been regarded as a subgenus of Turcica H. &A.Adams, 1854 (type species Turcica monilifera A. Adams, 1854 , by monotypy), but I consider Perrinia species to form a relatively well defined group which can be reasonably easily separated from the much larger Turcica s.s. species on account of their smaller size, stouter shells and strong spiral lirae inside the outer lip of the aperture. In the absence of data suggesting otherwise, I therefore accord Perrinia full generic status.

It should be noted that Kano et al. (2009) have shown that Turcica belongs within the Calliotropidae . This may also prove to be the case for Perrinia when sequence data become available, but I consider the overall facies of the shell of Perrinia to be closer to that of the Chilodontidae and thus maintain it here for the present.