Order Pleurotomariida Cox & Knight 1960
Superfamily Pleurotomarioidea Swainson, 1840
Family Portlockiellidae Batten, 1956
Genus Shansiella Yin 1932
Species carbonaria Norwood & Pratten, 1855

Norwood & Pratten (1855) first named Pleurotomaria carbonaria from calcareous shale in Illinois and reported its occurrence as very rare. However, evidence exists that Conrad identified these as Turbo insectus in 1835. There are many problems with Conrad’s work, from his single sentence description, warped illustration, and the loss of the specimen. His long and detailed sentence describes the turbinate and protruding shape, coarse revolving ornamentation, flattened whorl tops, and rounded aperture opening that is half the shell height. However, the illustration is a wreck; it is too tall and has whorls that are too round. Also, the aperture position is too far below to represent what we know today as Shansiella. If his specimen were available today and we could identify it as Shansiella, we would be using the name Shansiella insectus. All was not lost; two of Conrad’s gastropod species names from 1835 are valid today, Turbo tabulatus (=Worthenia tabulata) and Stylifer primogenia (=Strobeus primogenius). Two out of three is not bad. [For more information, see: The Curious Case of Turbo insectus].

Workers continued to report on the genus over the years until Yin (1932) named Shansiella from a specimen in China, and Knight et al. (1960) placed P. carbonaria under the name. Yin’s work was the completion of a colleague, Y. T. Chao’s work on gastropods. Unfortunately, Yin reported that Chao was “taken by bandits” in 1929.

The species is uncommon at SL-6553 and abundant at SL-6445. A few years of collecting resulted in over 100 specimens. The fissile nature of the limestone there helps produce good specimens. The ornament is well preserved but difficult to recover with great detail, as the matrix still sticks between the cords.

Between the spiral corded ornamentation are proscline growth lines on the upper whorls and opisthocline lines on the bottom whorls. Weather exposure produces better specimens at SL-6445, where sun, rain, and wind may remove the adhering matrix between the cords. Some examples expose well-defined details in the aperture. The shells often retain a bright white high magnesium calcite or original aragonite due to the excellent preservation environment at both locations. A microscope can see eroded specimens’ inner shell layer details.

At SL-6553, Shansiella with any detail are nearly impossible to recover. The hard, brittle matrix sticks like glue to the outer shells. I deposited an exceptionally large gastropod (CG-0144, now CM 54698) with a Shansiella form, a well-worn surface, and a selenizone impression to the Carnegie Museum. It could be an example of gigantism in a Paleozoic gastropod species or a lucky individual that survived to old age. It is almost three times larger than my largest Shansiella specimen. No known research exists on this condition, so these theories are pure speculation.

Fig. 1.—Shansiella carbonaria from the Pine Creek limestone at SL 6445. A medium-sized adult specimen showing spiral ridges, growth lines, and selenizone, CG-0516. Scale bar = 5 mm.
Fig. 2.—Shansiella carbonaria from the Pine Creek limestone at SL 6445. Apertural view of a large adult specimen showing spiral ridges, growth lines, and broad depressed selenizone, CG-0527. Scale bar = 1 cm.
Fig. 3.—Shansiella carbonaria from the Pine Creek limestone at SL 6445. A–C, Three views of a large adult specimen showing spiral ridges, growth lines, and selenizone; when uncoated and wet, the inner narce boundary can be seen on the columellar lip, CG-0601. Scale bar = 5 mm.
Fig. 4.—Shansiella carbonaria from the Pine Creek limestone at SL 6445. A, Abapertural view of a medium-sized specimen showing spiral ridges, growth lines, and broad depressed selenizone; B, spire view showing some morphing in the bottom left quadrant; CG-0504. Scale bar = 5 mm.
Fig. 5.—Shansiella carbonaria from the Pine Creek limestone at SL 6445. A, Apertural view of a small specimen showing base to whorl spiral ornament transition, selenizone, and flat columellar lip, CG-0219; B, tiny specimen in apertural view with a crushed base, CG-0537; C, tiny specimen in apertural view, CG-0538. Scale bar = 5 mm.
Fig. 6.—Species of Shansiella from the Pine Creek limestone at SL 6445. A, apertural view of an adult specimen, CG-0282; B, Example of…; CG-0424. Scale bar = 5 mm.
Fig. 7.—The aperture of Shansiella carbonaria showing the boundary of the inner nacre layer compared to the anterior margin of the shell; the shape of the selenizone at the margin can also be inferred from the figure; CG-0424. See Figure X-B for scale.
Fig. 8.—Shansiella carbonaria from the Pine Creek limestone at SL 6445. Apertural, abapertural. and spire views of an adolescent specimen with a gastropod lodged in the aperture, perhaps Meekospira, CG-0281; B, apertural view of a crushed shell, CG-0190. Scale bar = 5 mm.
Fig. 9.—Shansiella carbonaria from the Pine Creek limestone at SL 6445. Apertural, abapertural. and spire views of a crushed adolescent specimen, CG-0190. Scale bar = 5 mm.
Fig. 10.—Shansiella carbonaria from the Pine Creek limestone at SL 6445. Specimen with cleaned aperture showing column structure and detailed selenizone, CG-0669. Scale bar = 5 mm.
Fig. 11.—Shansiella carbonaria from the Pine Creek limestone at SL 6445. Specimen with poor surface details was cut in half and polished to show the shell layers, column, and body chamber profile, CG-0512. Scale bar = 5 mm.

References