Abstract

A new conchostracan species, Anomalonema (Pierrepruvostia) williamsii is described from the shale above the Upper Kittanning coal, Clearfield County, Pennsylvania. This is the first representative of the genus found outside the coal fields of northern France. Novojilov's new genus, Pierrepruvostia, is reduced to subgeneric status, and his subfamily Anomalonematinae is rejected. Two new subgenera of the genus Anomalonema are proposed: Pierrepruvostia and Anomalonema. The former lacks postero-dorsal recurvature and has a non-terminal beak; the latter has postero-dorsal recurvature and a terminal beak. Both subgenera share the generic character of tubercles (interrupted radial lirae) margining growth lines. This feature gives a scalloped appearance to growth line peripheries. Raymond's questionable assignment of Chernyshev's specimens to the Anomalonema is rejected, and these specimens are assigned to the Estheriella. The inferred relationship between Pruvost's "tubercles" and "indentations" on the new species is supported by measurements of distance between any 2 adjacent pairs of each. Almost complete agreement was found between these sets of figures. Comparison with measurements on valves of the living species Caenestheriella belfragei establishes the fact that distances between any 2 adjacent spines or setae bases is a hundredfold less than between any 2 tubercles or indentations. These data indicate that the latter features are "interrupted radial lirae" and could not have been spines or setae bases in the living animal.

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