Crassispira (Crassispira)

Crassispira woodringi
Published 22 January 2023

Crassispira is one of those conoid genera that has tended to draw species into it, impelled by the force of its taxonomic gravity. As noted by Powell (1966), various authors have tended to award it any conoid species exhibiting a strong subsutural fold. Among modern species, the recognition of the true Crassispira’s distinctive radula, consisting of a single pair of marginal teeth, has allowed the genus to be restricted to a more natural cluster centred around the tropical western coast of the Americas. Fossil taxa, however, cannot be assessed in this way.

Holotype of Crassispira woodringi, from Olsson (1930).

One fossil species that remains in Crassispira’s orbit is C. woodringi. This species was described by Olsson (1930) from the Eocene-age Talara Formation of northern Peru. Specimens were around three centimetres long, with a bit less than half that length taken up by the aperture, and a bit less than a centimetre wide. Whorls were slightly convex and feebly shouldered. The anal fasciole (the section of whorl above the shoulder marked by growth lines from the anal canal) was broad and sloping but weakly constricted. The anal sinus was deep and narrow, and placed just above the shoulder, some distance below the suture. Growth lines were strong but the remaining sculpture was weak, with axial sculpture represented by eight low knob-like ribs on the last turn of the shoulder, and spiral sculpture of weak but numerous threads. The siphonal canal was moderately long, stout and strongly twisted, sometimes developing a distinct fold at the tip.

As far as I could find, Crassispira woodringi does not appear to have been examined in any detail since Olsson’s original description. Though its Peruvian location does put it within the heartland of modern Crassispira (a statement that admittedly may or may not mean anything by the time we get back to the Eocene), it differs from other members of the genus in interesting ways. The shell is more slender than the average Crassispira, and the siphonal canal is distinctly longer. The anal fasciole appears more strongly constricted in modern Crassispira which thus tend to have a more distinct ‘waist’ below each suture. Whether these distinctions add up to enough to render C. woodringi’s status as a Crassispira into question, I am of course not in the least bit qualified to say. That would have to wait for a more informed analysis.

References

Olsson, A. A. 1930. Contributions to the Tertiary paleontology of northern Peru: part 3, Eocene Mollusca. Bulletins of American Paleontology 17: 1–96, pls 91–12.

Powell, A. W. B. 1966. The molluscan families Speightiidae and Turridae. An evaluation of the valid taxa, both recent and fossil, with lists of characteristic species. Bulletin of the Auckland Institute and Museum 5: 1–184.

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