Gisortia undetermined

Groves, Lindsey & Squires, Richard L., 2023, Revision of northeast Pacific Paleogene cypraeoidean gastropods, including recognition of three new species: implications for paleobiogeographic distribution and faunal turnover, PaleoBios 40 (10), pp. 1-52 : 20-22

GISORTIA SP.

FIGS. 6K–M

Gisortia clarki Ingram, 1940 . Squires, 1987. p. 35, figs. 39–41 [as Gisortia new species? in caption]. Not Gisortia clarki Ingram, 1940 .

Referred Specimen—Hypotype (of Squires, 1987) LACMIP 16243.1 , LACMIP Type 7466 (Figs. 6K–M), LAC- MIP Locality 16243 [= Locality 40848 [ex CSUN Locality 848]), Juncal Formation, Canton Canyon, Ventura County, California.

Occurrence— Juncal Formation. “Capay Stage,” Turritella uvasana infera fauna, LACMIP Localities 16156 [= LACMIP Locality 40837; ex CSUN Locality 837] and 16243 [= LACMIP Locality 40848; ex CSUN Locality 837], in an area just east of Sharps Canyon and southeastward toward Canton Canyon, Whitaker Peak area, Los Angeles County, southern California.

Description— Shell large, length 122 mm, width 75 mm, height 51 mm. Shell ovate. Anterior and posterior ends flattened somewhat and projecting. Aperture nar- row, curving left posteriorly but becoming less curved anteriorly. Outer lip (anterior half) with several small teeth; presence of any dentition on rest of aperture is not known.

Remarks— A large complete specimen is known,but it is poorly preserved as a partial internal mold (steinkern). In addition, a large fragment (length 90 mm) was found in same-age rocks of the Juncal Formation approximately 0.5 km to the west in Sharps Canyon of the Whitaker Peak area ( Squires 1987), LACMIP 40837.1, LACMIP Local- ity 16156 [= LACMIP Locality 40837; ex CSUN Locality 837]. Most of the dorsal shell convexity of the complete specimen is represented by an internal mold (steinkern),

Figure 7A–C. Cypraeidae , genus and species indeterminate, Lodo Formation (basal) (Paleocene, Seldanian Stage), Tumey Hills, Fresno County, central California. Basal (A), dorsal (B), and right (labral) (C) views, 1.3x, length 39 mm, width 25 mm, height 22 mm, of hypotype CASG 61666.06, CASG Locality 61666. D–F. Eocypraea batequensis (Groves, 2011) , Bateque Formation (Eocene, “Capay Stage”), Mesa La Salina, Baja California Sur, México. Basal (D), dorsal (E), and right (labral) (F) views, 4.8x, length 9.4 mm, width 6.5 mm, height 5.1 mm,

of holotype IGM 5174 , LACMIP Locality 16951 [ex CSUN Locality1220b]. G–I. Eocypraea crescentensis (Groves, 2011) , Crescent Formation (Eocene, “Capay Stage”), Larch Mountain , Black Hills area , Thurston County, Washington. Basal (G), dorsal (H), and left (columellar) (I) views, 3.9x, length 10.9 mm, width 7.6 mm, height

6.1 mm, of holotype LACMIP 16655.40 , LACMIP Type 13646, LACMIP Locality 16655 [= LACMIP Locality

41563; ex CSUN Locality 1563]. J–L. Eocypraea jimgoederti (Groves, 2011) , lower McIntosh Formation (middle Eocene, “Transition Stage” to “Tejon Stage”), Doty Hills, Lewis County, Washington. Basal (J), dorsal (K), and left (columellar) side (L) views, 3.5x, length 12.7 mm, width 8.2 mm, height 6.9 mm, of holotype LACMIP 41573.1, LACMIP Type 13647, LACMIP Locality 41573 [ex CSUN Locality 1573]. M–O. Eocypraea judithsmithae n. sp., Llajas Formation (Eocene, “Domengine Stage”), north side Simi Valley, Ventura County, southern California. Basal (M), dorsal (N), and left (labral) (O) views, 1.5x, length 26.6 mm, width 18.4 mm, height 12.6 mm, of holotype LACMIP 40372.1, LACMIP Type 14940 ( LACMIP Locality 40732).

and its spire is obscured by matrix. The Juncal Forma- tion specimen of Gisortia sp. differs from Gisortia clarki by having an ovate shell, a narrower shell, a narrower inner lip, and the presence of wide, flattened anterior and posterior margins.

The Juncal Formation specimens of Gisortia sp. are somewhat similar to a specimen of Gisortia gigantea Münster in Keferstein, 1828, from India as illustrated by Vredenburg (1927: p. 59, 60, pl. 13, fig. 2). Gisortia gigantea , which is of middle Eocene (Lutetian age) and known from France, England, and India, can have a wide range of variation in its posterior canal region owning to the absence or presence of elaborately shaped phlanges and/or wide spines. These variants usually have been assigned to subspecies of Gisortia gigantea or assigned a different species name. See Pacaud (2008) for clarifi- cations. The Juncal Formation species of Gisortia differs from G. gigantea by having a more elongate shell shape with a posterior flattening of the shell and no evidence of any posterior phlanges.