Subepona leahae, 2023

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 : 12

SUBEPONA LEAHAE SQUIRES AND GROVES N. SP.

FIGS. 4O–Q

Cypraea species indeterminate. Squires, 1988. p. 12, fig. 23. Groves and Squires, 2021. p. 227.

Eocypraea (Eocypraea) castacensis ( Stewart, 1926 [1927]). Squires, 2000. p. 896.

Zoobank ID — LSID: urn:lsid:zoobank.org:act:363755AA-DB51-40D7-B996-A9EBA6EBBD85

Holotype and Type Locality— LACMIP 40374.79 , LACMIP Type 14936 ( Figs. 4O–Q ), length 29.5 mm, width 13.9 mm, height 15.1 mm. LACMIP Locality 7242 [= LACMIP 40374 ; ex CSUN Locality 374], Llajas Formtion, “Stewart bed,” Las Llajas Canyon , north side of Simi Valley , Ventura County, southern California.

Paratype — LACMIP 16178.1, LACMIP Type 7704, length 23.2 mm, width 17.1 mm, height 13.8 mm, LACMIP Locality 16178 [= LACMIP Locality 40984; ex CSUN Locality 984) Lockwood Valley, Ventura County, California. This specimen was formerly hypotype LACMIP 7704 (of Squires, 1988: p. 12, fig. 23), of Eocypraea castacensis ( Stewart, 1926 [1927]).

Occurrence —“ Domengine Stage”: Juncal Formation?, Lockwood Valley , Ventura County, southern California ; Llajas Formation, Las Llajas Canyon (“Stewart bed,” ex CSUN Locality 374), Ventura County, California .

Etymology— Named for Leah Rose Regan, granddaughter of R.L. Squires (who collected the type material).

Description— Shell medium size, moderately inflated, aperture fairly straight except for moderate bend posteriorly, fossula smooth, teeth numerous and small on entire lengths of both lips, with those on the outer lip becoming slightly coarser near anterior end of shell. Posterior end of shell with outer lip projecting out over the inner lip. Anterior end with an elongate, linear projection on each lip.

Remarks— The two known specimens of Subepona leahae have good preservation. The holotype is from the “Stewart bed” of the Llajas Formation, and the paratype is from the Juncal Formation?, Lockwood Valley, Ventura County, southern California.

Squires (1988: p. 12, fig. 23) reported a specimen (hypotype LACMIP 7704) of “ Cypraea species indeterminate” [now identified as Subepona leahae ] from LACMIP Locality 40984 [ex CSUN Locality 984] in the Juncal Formation? in Lockwood Valley, Ventura County, southern California. This locality is in the upper 100 m of the Juncal Formation, based on work by Squires (2000: p. 896), who identified this same specimen as Eocypraea (Eocypraea) castacensis and revised its age to the younger “Domengine Stage,” instead of the previously reported ( Squires 1988) “Capay Stage.”

Subepona leahae differs from S.goedertorum by having much finer denticulation.

Figures

Figure 4 (previous page). A–C. Nucleolaria cowlitzensis Groves, 1994, Cowlitz Formation (middle Eocene, upper “Tejon Stage”), Vader area, south-central Lewis County, Washington. Basal (A), dorsal (B), and left (columellar) side (C) views, 1.9x, length 27.2 mm, width 17.3 mm, height 11.3 mm, of holotype UCMP 39837, UCMP Locality D-8040. D–H. Propustularia kemperae (Nelson, 1925), Santa Susana Formation, (Paleocene, Selandian Stage), north side Simi Hills, Ventura County, southern California. Basal (D), dorsal (E), and right (labral) side (F), and views, 2.2x, length 21 mm, width 17.3, height 12 mm, of holotype CASG 391.01 [ex CASG 987], Locality CASG 391. Dorsal (G) view, 2.6x, length 18.2 mm, width 14.9, height 11.2 mm, of hypotype LACMIP 22307.6, LACMIP Type 14918 (LACMIP Locality 22307). Basal (H) view, 2.2x, length 21 mm, width 17.3, height 12 mm, of paratype UCMP 30541, UCMP Locality 3764. I–N. Subepona goedertorum (Groves and Squires, 1995), Crescent Forma- tion (Eocene, “Capay Stage”), Black Hills, Thurston County, Washington. Basal (I), dorsal (J), left (columellar) lateral (K), and right (labral) (L) views, 2.8x, length 19.4 mm, width 12.3, height 10.8 mm, of holotype LACMIP 16655.23, LACMIP Type 12375, LACMIP Locality 16655 [=LACMIP Locality 41563; ex CSUN Locality 1563]. M–N, Juncal Formation, Canton Canyon, Whitaker Peak area, Ventura County, southern California. Basal (M) and dorsal (N) views, both 2.4x, length 19.4 mm, width 13.9, height 9.4 mm, of hypotype LACMIP 40807.1, LACMIP Type 14935 (LACMIP Locality 40807 [= LACMIP Locality 16191, ex CSUN Locality 807]). O–Q, Subepona leahae n. sp., Llajas Formation (Eocene, “Domengine Stage”), north side Simi Valley, Ventura County, southern California. Basal (O), dorsal (P), and left (labral) side (Q) views, 1.6x, length 29.5 mm, width 13.9, height 15.1 mm, of holotype LACMIP 40374.79, LACMIP Type 14936, (LACMIP Locality 40374).