Revised descriptions of New Zealand Cenozoic Mollusca from Beu and Maxwell (1990)
(Pl. 25h): holotype, Pakaurangi Point, Kaipara Harbour, Altonian (TM1288, GNS)
Beu & Maxwell (1990): Chapter 11; p. 228; pl. 25 h.
Synonymy: Verconella bartrumi Laws 1941b, p. 147
Description: Small for genus (height c. 60 mm), broadly fusiform, spire 0.4 total height. Protoconch relatively small, mamillate, of 2 smooth, strongly convex whorls. Teleoconch of 8 whorls, convex at first, then becoming sharply shouldered, angulation near middle of whorl at first, then moving much lower. Last whorl with basal subangulation, broadly excavated below, with long, slightly recurved neck. Axial sculpture of prominent, rounded costae reaching from suture to suture on early whorls, later becoming obsolete on all except lower part of sutural ramp and slightly tubercular on periphery, dying out on base of last whorl; 7 costae per whorl. Spiral sculpture of fine threads over whorl surface, with a stronger thread on periphery and several of similar strength on base and neck. Aperture ovate; columella strongly concave above, twisted to left below; siphonal canal moderately long, slightly curved, shallowly notched.
Comparison: Penion bartrumi is distinguished from most New Zealand fossil Penion species by its small size and small protoconch. P. parans (Altonian, Clifden) is similar but has a considerably larger protoconch, more prominently angled teleoconch whorls, the shoulder at a higher position on adult whorls, and somewhat stronger spiral sculpture. These species probably represent a warmer-water group of Penion than the large, contemporaneous species from North Otago and Canterbury (e.g., P. marwicki, Pl. 20m), and the small protoconch is shared with Australian fossil and living Penion species (Ponder 1973).
Distribution: Altonian, Pakaurangi Formation, Pakaurangi Point, Kaipara Harbour (type) (rare).
Cite this publication as: "A.G. Beu and J.I. Raine (2009). Revised
descriptions of New Zealand Cenozoic Mollusca from Beu and Maxwell (1990). GNS
Science miscellaneous series no. 27."
© GNS Science, 2009
(Included with a PDF facsimile file copy of New Zealand Geological Survey Paleontological Bulletin 58 in CD version from: Publications Officer, GNS Science, P.O. Box 30368 Lower Hutt, New Zealand)