Araucocharopa gallardoi gen. et sp. n. de Charopidae (Mollusca: Gastropoda: Stylommatophora) del sur de Chile

Abstract

Araucocharopa gallardoi gen. et sp. n. of Charopidae (Gastropoda: Stylommatophora:
Punctoidea) from Southern Chile. Araucocharopa gallardoi gen. et sp. n. from Southern Chile is described.
It is characterized by a small trochoid shell (mean diameter: 1.8 mm), 4 ½ - 5 convex whorls, body whorl
subcuadrangular; elevated spire (mean height / diameter: 0.74); adult sculpture of high, prominent and vertical
120 axial ribs; periostracal lamelae growing on the axial ribs; protoconch of 1 ¾ whorls with microsculture
consisting of 12 spiral costulae with barely visible irregular rings; semilunate aperture descending basally;
umbilicus very narrow. The ringed spiral costulae of protoconch is a distinctive feature into the family Charopidae.
As part of the discussion, the protoconchs of type species of Stephanoda and Austrodiscus are described for the
first time, the embrionic sculpture of S. dissimilis shows irregular axial and spiral fine ribs, and delicate incisurae;
in A. twomeyi the protoconch begins smooth, showing axial ribs crossed by fine spirals costulae, not well separated
from teleoconch.