Species / Austroaporrhais Stilwelli
Stromboidea
Original Description of Austroaporrhais stilwelli by Zinsmeister and Griffin, 1995
- "Shell moderately large-sized, with a very high turreted spire of about 10 whorls; spire angle of 28-30 degrees; protoconch of two smooth convex whorls; keel initially faint, but rapidly strengthening into a moderately strong angulation with both anterior and posterior portion of whorl slightly concave; keel located slightly anterior to mid-point of whorl, second poorly developed keel present on body whorl; shell surface ornamented with numerous spiral threads, averaging about 24-28 on penultimate whorl; axial ornamentation on penultimate whorl consists of about 18 sharp, slightly elongated, opisthocline nodes, especially strong on keel; aperture sublenticular, elongated, with strongly curved anterior process excavated by siphonal canal; outer lip expanded into subquadrate wing, inclined at about 25 degrees to shell axis and produced into two long, almost straight, thin digitations with the posterior one longer; interior surface of digitation has narrow groove, which becomes obsolete near the proximal end; outer margin of wing slightly thickened; inner lip of aperture covered by very thin callous pad."
Locus typicus: Seymour Island, James Ross Island group, Antarctic Peninsula, Antarctica
Stratum typicum: Maastrichtian part of the López de Bertodano Formation, upper Cretaceous
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