Specimen of the Week — Siphonochelus (Pilsbrytyphis) gabbi

I apologize for not posting many photos in the past week. I have been very busy going through several years’ worth of accumulated fossils and trying to organize my collection so I can actually find things when I need them! (The specimen figured below is in fact one that I haven’t been able to find since moving to Pennsylvania two years ago!)

In keeping with my tendency to name typhines as “Specimen of the Week” more often than any other type of muricid, this week’s featured specimen is Siphonochelus (Pilsbrytyphis) gabbi (Brown and Pilsbry, 1911).

Siphonochelus (Pilsbrytyphis) gabbi (click to enlarge)

Siphonochelus (Pilsbrytyphis) gabbi (click to enlarge)

This species was originally described from the Gatun Formation of Panama, although Vokes (1989) mentions having specimens from the Rio Banano Formation of Costa Rica as well. Woodring (1959) referred to the surface ornamentation of Pilsbrytyphis as “peanut-shell” in nature when he first named the subgenus. In 1969, Gertman named two additional species of Pilsbrytyphis from Panama — S. (P.) darienensis, which has “axially directed, longitudinal wrinkles that follow the growth pattern of the shell” (p.180), and S. (P.) woodringi, which also has an axially oriented sculptural pattern, as opposed to the spirally oriented sculpture of S. (P.) gabbi.

Unfortunately, I am not really sure where my specimen comes from. I bought it, and several other fossil typhines from the Western Atlantic region, from an overseas dealer a few years ago. It was labeled as “Laevityphis curvirostrius Weisbrod, Venezuela, Paraguana Formation” (note the misspellings as well as the species-locality mismatch for what I assume was actually intended to be called S. (L.) curvirostratus (Conrad, 1848) from the Oligocene of Mississippi and Mexico). I also received a specimen of what appears to be a typical Siphonochelus (Laevityphis) labeled as “Pilsbrytyphis gabbi Pilsbry & Brown, Venezuela, Mare Formation, Upper Miocene.” So while the locality data and IDs of both specimens are suspect, I believe that this is a legitimate specimen of S. (P.) gabbi, of unknown origins. The color of the matrix does match that of many sites in Venezuela, however. (Perhaps I need to add a “Name That Locality” category to my blog?) 🙂

This is an appropriate time to refresh the reader’s memory of an earlier “Specimen of the Week” post, where I figured specimens of Typhis (Rugotyphis) keenae Gertman, 1969 from the Miocene Chipola Formation of Florida, some of which also have this unusual surface ornamentation.

Typhis (Rugotyphis) keenae Gertman, 1969 (with and without ornamentation)

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References:

Gertman, R. L. (1969). “Cenozoic Typhinae (Mollusca: Gastropoda) of the Western Atlantic Region,” Tulane Studies in Geology and Paleontology, Vol. 7(4), pp. 143-191.

Vokes, E. H. (1989). “Neogene Paleontology in the Northern Dominican Republic. 8. The Family Muricidae (Mollusca: Gastropoda),” Bulletins of American Paleontology 97.

Woodring, W. P. (1959). “Geology and Paleontology of Canal Zone and Adjoining Parts of Panama; Part 2, Description of Tertiary Mollusks (Gastropods: Vermetidae to Thaididae),” U. S. Geological Survey Professional Paper 306-B.