Argopecten ventricosus impostor (Hanna, 1924)
HANNA, G. D. 1924. Rectifications of nomenclature. Proceedings of the California Academy of Sciences [4th Series], 13 (10): 151-186. [p. 177]
1917 Pecten proteus Nomland 1917
1924 Pecten impostor Hanna, 1924 [nomen novum pro Pecten proteus Nomland, 1917]
1924 Pecten impostor Hanna, 1924 [nomen novum pro Pecten proteus Nomland, 1917]
Pecten proteus, n. sp.; J. O. Nomland, 1917, The Etchegoin Pliocene of Middle California, plate 6, figures 2, 2a-2c.
|
«Pecten proteus Nomland, Univ. Calif. Publ. Geol., Vol, 10, 1917, p. 232, pl. 6, figs. 2, 2a, 2b, 2c, Etchegoin Pliocene, California.
Not Pecten proteus Sowerby, Thes. Conch., 1847, p. 59, pl. 13, figs. 53, 54. Four other references are given to the name by Von Teppner in C. Diener, Foss. Catalogue, Pars 15, p. 197, 1922. Nomland's name is an exact homonym of the well-known species of Sowerby. The other references given by C. Diener have not been checked. There is also a Pecten protei Munster²² (cited by d'Orbigny in his Prodrome) which would probably throw out even Sowerby's name upon a strict application of the rules. Monterosato²³ proposed the genus name "Proteopecten" for some species named "Pecten proteus" but not the one of Moody.» ²² Beitrag. 1841, Vol. 4, p. 72, pl. 7, fig. 6. ²³ Journ. Conch., Vol. 47, 1899, p. 187. GEORGE DALLAS HANNA, 1924
|
«Original description.— "Shell thin, equilateral, equivalve, compressed, with smooth regularly convex margins. Dorsal margins slightly concave; apical angle about 95 degrees. Right valve ornamented externally by 21-24 wide, moderately high, rounded ribs; on each side of major ribs is usually a faint auxiliary riblet; interspaces between major ribs less than width of ribs; anterior ear slightly longer than posterior, sculptured by about five low radial ridges and indistinct incremental lines; posterior ear ornamented with about seven low, radial ridges and nearly invisible incremental lines. Left valve in general similar to right, but has higher, more strongly rounded, major ribs with narrow interspaces; anterior ear with about seven radiating lines. Dimensions of rather small left valve of type: height, 37 mm.; width, 33 mm.; width of hinge line, 17 mm."
Holotype.—UCMP 11089. Type locality.— UC 2991. Fresno County, Calif. Upper Etchegoin Formation, Pliocene. Comparison.— "Specimens of this species found in the Coalinga region have heretofore been identified as Pecten deserti Conrad. On comparison of P. deserti from the type locality at Carrizo Mountain, San Diego County, with P. proteus, n.sp., several marked differences may be observed. In P. deserti the ribs are higher, flatter above, with more nearly vertical sides; on the left valve the ribbing continues without interruption from ears over the outer depressed dorsal margins, while in P. proteus, n. sp., the corresponding areas have no ribs. The ears of P. deserti are larger, more strongly curved, and have less depression where ears join dorsal margins of shell; also the dorsal margins show less marked concavity." (Nomland, 1917a, p. 232) Argopecten circularis impostor differs from the living California A. circularis Sowerby and its allies in having a smaller thinner shell and smaller ears. Argopecten deserti appears to have not quite so many ribs, and at least some specimens have ribs on the lateral areas; on A. c. impostor the lateral areas are smooth. A. ci.rcularis eldridgei is smaller than A. circularis impostor and has a thicker shell. (Woodring and others, 1940, p. 91) Comments.— The holotype is a small, moderately thick-shelled, slightly inequilateral left vaive. The left valve ribs are grooved along the edges, and they, and the narrower interspaces, seem to have been covered by imbricated microsculpture. Geographic range.—Middle and southern California. Geologic range.— Pliocene. Occurrence in Califomia.— Cascajo Conglomerate Member, San Joaquin and upper part of Etchegoin (Woodring and others, 1940) Formations.» MOORE, E. J. 1984. Tertiary Marine Pelecypods of California: Propeamussidae and Pectinidae. United States Geological Survey Professional Paper, 1228-B: iv. B1-B112 p., figs. 1-2, pls. 1-42. [p. B36]
|
Argopecten circularis impostor (G D. Hanna); E. J. Moore, 1944, Tertiary Marine Pelecypods of California, plate 10, figure 1.
|
«Aequipecten was found only in the San Joaquin formation. Aequipecten circularis impostor (Hanna) is locally abundant in the Pecten zone (pI. 13, figs. 3, 4, 6-9), and fragmentary remains of a similar form occur in the Cascajo conglomerate member. The Pecten zone variety differs from the living California A. circularis Sowerby and its allies in having a smaller thinner shell and smaller ears. These fossils were identified by Arnold as A. deserti Conrad, the type of which is from the Colorado Desert. They are probably very closely related to that species, which, however, appears to have not quite so many ribs, and at least some specimens have ribs on the lateral areas. On the Pecten zone fossils the lateral areas are smooth. A. circularis eldridgei (Arnold) (pI. 24, figs. 10-13), found only in the Cascajo conglomerate of South Dome, is smaller than A. circularis impostor and has a thicker shell. The Cascajo specimens are smaller and less inflated than specimens from the type locality near McKittrick, where they occur in strata suggested in the present report as representing the equivalent of the Cascajo. This small pecten was heretofore recorded only at the type locality. (W. P. W., R. S.)»
WOODRING, W. P., R. STEWARD & R. W. RICHARDS. 1940. Geology of The Kettleman Hills oil field California. United States Geological Survey Professional Paper, 195: 1-170, pls. 1-57. [p. 91]
|
Aequipecten circularis impostor (Hanna); Woodring, W. P., R. Steward & R. W. Richards, 1940, Geology of The Kettleman Hills oil field California, plate 13, figures 3, 4, 6-9.
|