Eocypraea novasumma, (NELSON, 1925)

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 : 24-26

EOCYPRAEA NOVASUMMA ( NELSON, 1925)

FIGS. 8A–C

Ovula novasumma Nelson, 1925 . p. 398, chart opposite p. 402, 425; pl. 57, fig. 2. Keen and Bentson, 1944. p. 183. Zinsmeister and Paredes-Mejia, 1988. p. 12.

Eocypraea (Eocypraea) novasumma (Nelson) . Schilder, 1932. p. 214 [as E. (E.) novasumma ]. Schilder, 1941. p. 102. Weaver, MS [1959]. p. 480; pl. 21, figs. 1, 2. Groves, 1992. p. 106. Groves, 1993. p. 11. Groves, 1997. p. 7. Groves, 2011. p. 46 (table 1).

Cypraea novasuma [sic] (Nelson). Ingram, 1947a. p. 60, 98, pl. 3, fig. 9. Ingram, 1947b. p. 147.

Eocypraea (Eocypraea) sabuloviridis ( Whitfield, 1892) . Schilder and Schilder, 1971. pp. 66, 137. Not Eocypraea sabuloviridis ( Whitfield, 1892) .

Eocypraea novasumma (Nelson) . Zinsmeister, 1974. p. 129; pl. 13 [not pl. 8 as in text], figs. 8, 9; Zinsmeister, 1983. pp. 64, 69, pl. 3, figs. 1, 2. Groves and Squires, 2021. p. 227 (as Cypraea ), 232. Fehse, 2021. p. 42.

Eocypraea novasumma (Nelson) . Paredes-Mejia, 1989. p. 195, 196, pl. 4, figs. 8–10. Perrilliat, 2013. p. 134, figs. 4.3, 4.4. Not Eocypraea novasumma ( Nelson, 1925) .

Holotype and Type Locality— UCMP 30499 ( Figs. 8A–C ), length 15.8 mm, width 11.9, height 9.3 mm. UCMP Locality 3776,north side Meier Canyon , south side of Simi Valley , Ventura County, southern California.

Referred Specimens—Hypotype (of Zinsmeister, 1974, 1983) UCR 6871/13 (not UCR 3776/1), UCR Locality 6871, from the Santa Susana Formation on the north side of Simi Hills, Simi Valley, Ventura County, southern California. Hypotype (of Paredes-Mejia, 1989) IGM 4388, PU Locality 1334, Mesa San Carlos, Baja California, México (= hypotype IGM 4367 of Perrilliat, 2013).

Occurrence— Middle Paleocene, southern California to northern Baja California, México. Selandian Stage: Santa Susana Formation (lower part), north side Simi Valley, Ventura County, southern California ( Zinsmeister 1974, 1983; Groves 1992, 1993, 1997, 2011).

Etymology— Originally from Latin novasumma ‘new ones’ … a new species.

Description— Shell small and smooth; inflated; left-lateral side more inflated than right-lateral side (thereby producing moderate “lop-sided” shape. Shell widest medially. Basal surface slightly inflated. Left-lateral posterior side of shell lowly protruding. Spire covered (involute?). Aperture straight, widens anteriorly, and prominently curved posteriorly adxially (to the left). Outer lip broad, flattish and with very subdued small teeth. Inner lip teeth also subdued and apparently more numerous and more closely spaced than those on outer lip.

Remarks— Preservation of the holotype of this species’ dentition is very poor. The anteriormost end of the holotype is missing. Only a few specimens are known of the small-sized species. In the Simi Hills, E. novasumma occurs only low in the Santa Susana Formation in Runkle and Meier canyons, where its type locality is in the vicinity of the type locality of Propusularia kemperae , whose geologic age was discussed earlier in this present paper and is of Selandian age. A poorly preserved specimen from the Santa Susana Formation, Quarry Canyon area, Santa Monica Mountains, Los Angeles County, California ( LACMIP 11677.1, LACMIP Type 14927), LACMIP Locality 11677, may be E. novasumma . An additional poorly preserved internal mold from the Sepultura Formation, Santa Catarina, Baja California, México ( LACMIP 6364.1, Type LACMIP 14928) ( LACMIP Locality 6364) may also be E. novasumma .

Schilder and Schilder (1971) listed E. novasumma as a synonym of E. sabuloviridis ( Whitfield, 1892, pp. 223, 224, pl. 32, figs. 20–22), of the Eocene Greensand Marls of New Jersey but they offered no explanation for this assignment. The holotype of E. sabuloviridis is a poorly preserved internal mold, which does not resemble E. novasumma .

In the Sepultura Formation, Mesa San Carlos, Baja California, México, Eocypraea novasumma has been reported from the same area as where specimens of Propustularia kemperae ( Paredes-Mejia 1989: p. 503; Perrilliat 2013: p. 29) were reported. However, the specimen, with different IGM hypotype numbers, reported by both Paredes-Mejia (1989) and Perrilliat (2013) is poorly preserved and does not favorably compare to the holotype and is likely another species.

Figures

Figure 8A–C. Eocypraea novasumma (Nelson, 1925), Santa Susana Formation (Paleocene, Thanetian Stage), Runkle Canyon, north side Simi Hills, Ventura County, southern California. Basal (A), dorsal (B), and right-labral (C) views, 3.2x, length 17 mm, width 11.6 mm, height 9.3 mm, of holotype UCMP 30499, UCMP Locality 4776. D–F. Eocypraea takeosusukii Groves, 2011, “Martinez” Formation (Paleocene, Thanetian), Lower Lake area, Lake County, northern California. Basal (D), dorsal (E), and left-lateral (columellar) views, 2.6x, length 18.8 mm, width 14.4 mm, height 11.2 mm, of holotype LACMIP 7045.1, LACMIP Type 13645, LACMIP Locality 7045 [ex CIT Locality 1580]. G–I. Eocypraea sp., cf. E. inflata (Lamarck, 1802), “Domengine Formation” (Eocene, “Domen- gine Stage”), Reef Ridge, Kings County, central California. Basal (G), dorsal (H), and right (labral) (I) views, 1.8x, length 26 mm, width 17.7 mm, height 13 mm, of hypotype UCMP 15815, Locality UCMP A-1282. J–L. Eocypraea sp. Lodo Formation (basal part) (Paleocene, Thanetian Stage), Tumey Hills, Fresno County, central California. Basal (J), dorsal (K), and right (labral) (L) views, 1.5x, length 33 mm, width 21.5 mm, height 19 mm, of hypotype CASG 61666.04 [ex LSJU 10236], CASG Locality 61666 [ex LSJU Locality 2073; = UCMP Locality A-9717]. M–P. Grovesia castacensis (Stewart, 1926 [1927]), Tejon Formation (Eocene, “Tejon Stage”), Tehachapi Mountains, Kern County, southern California. Basal (M), dorsal (N), and left (columellar) (O) views, 4.5x, length 12.2 mm, width 7.8 mm, height 5.9 mm, of holotype UCMP 11690, Grapevine Canyon, UCMP Locality 452. Basal (P) view, 3.4x, length 15.5 mm, width 9.1 mm, height 6.9 mm, of hypotype LACMIP 41206.2, LACMIP Type 14941, base of Metralla Sandstone Member, Live Oak Canyon, LACMIP Locality 41206.