Propustularia kemperae, (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 : 9-10

PROPUSTULARIA KEMPERAE ( NELSON, 1925)

FIGS. 4D–H

Cypraea kemperae Nelson, 1925 . pp. 397, chart op- posite 402, 424; pl. 56, figs. 9, 10; pl. 57, fig. 4. Ingram 1942. p. 104; pl. 9, figs. 8, 9. Keen and Bentson, 1944. p 152. Ingram, 1947a. p. 97; pl. 7, figs. 2, 3. Ingram, 1947b. p. 147. Zinsmeister and Paredes-Mejia, 1988. p. 12.

Propustularia kemperae (Nelson) . Schilder, 1932. p. 158 [as P. kemperae ]. Schilder, 1941. p. 89. Weaver, MS [1959]. p. 483; pl. 21, fig. 4. Schilder and Schilder, 1971. pp. 59, 125. Zinsmeister, 1974, p. 130; pl. 13 figs. 5–7 [as kempera]. Paredes-Mejia, 1989. p. 196–198; pl. 4, figs. 4, 5. Groves, 1992. p. 106. Groves, 1993. p. 11. Lorenz, 2017. p. 211. Groves and Squires, 2021. pp. 227 (as Cypraea ), 286 (as kempera).

Propustularia kemperea [sic] (Nelson). Zinsmeister, 1983, pp. 64, 68, pl. 2, figs. 22–24 [as kempera].

Holotype and Type Locality— CASG 391.01 [ex CAS 987 ] (Figs. 4D–F), length 20.8 mm (anterior end missing), width 17.3 mm, height 11.9 mm. CASG Local- ity 391, Santa Susana Formation, between Runkle and Meier canyons, north side of Simi Hills , Ventura County, southern California.

Paratype — UCMP 30541 (Fig. 4H), length 21.0 mm (portion of anterior end missing), width 16.9 mm. height 11.7 mm , UCMP Locality 3764, in vicinity of the type locality of this species.

Referred Specimens—Hypotype LACMIP 22307.6, LACMIP Type 14918 (Fig. 4G), LACMIP Locality 22307 [ex UCLA Locality 2307], Santa Susana Formation, Meier Canyon, Simi Hills Ventura County, southern California. Hypotype (of Zinsmeister, 1974, 1983) UCR 4573/20. Two additional specimens from UCMP Locality A6737, Simi Valley, Ventura County, California and one complete specimen (length 19.5 mm, width 14.8 mm and height 10.07) and four fragments CASG 391.03 (topotypes) from CASG Locality 391 are noted.

Occurrence—Selandian Stage: Lower part of Santa Susana Formation, north side of Simi Hills, Ventura County, southern California ( Nelson, 1925) (see remarks below).

Etymology– Originally named for the late Mrs.Dorothy Kemper Palmer [1897-1947] ( UCMP).

Description— Shell small size. Moderately inflated, dorsum mostly smooth. Base and adjacent rostrate mar- gins heavily calloused with crenulations (elongated spiral ribs continuous with apertural teeth). Aperture generally straight or strongly curved anteriorly to left; aperture significantly widening anteriorly. Apertural crenula- tions prominent, numerous, long, and extending across both outer and inner lips and extending short distance onto both sides of last whorl. Approximately 12 strong crenulations on right-lateral side of base; approximately 21 weak to strong crenulations (seven of which on the medial area weakest and shorter) on left-lateral side of base; and crenulations on right-lateral side stronger than those on left-lateral side. Fossula prominent and moder- ately long. Posterior terminations somewhat extended on both sides of base. Anterior terminations less obvious.

Remarks— The 11 known specimens (see above) of Propustularia kemperae range in preservation from poor to moderately good. The holotype is figured in the present report with its anterior end complete. That is how is looked when the senior author photographed it. In recent years, however, the left side of the anterior end was broken off, and its whereabouts are unknown.

In the NEP region, P. kemperae is known only from the Santa Susana Formation in the Simi Hills of south- ern California. This species occurs only low in the Santa Susana Formation, and the type locality of this species is on a divide between Runkle and Meier canyons, where it co-occurs ( Nelson 1925) with the gastropods Mesalia martinezensis ( Gabb, 1869) and Heteroterma trochoidea Gabb, 1869 . The geologic range of the former is late Danian to early Thanetian ( Squires and Saul 2007), and the range of the latter is late Danian to early Selandian ( Saul 1988). Based on the overlap of the geologic ranges of these two species, an early Selandian age is indicated for P. kemperae .

The hypotypes of Paredes-Mejia (1989: pp. 196–198, pl. 4, figs. 4, 5 [ IGM 4389]) and Perrilliat (2013: p. 133, figs. 3.41, 3.42 [ IGM 4365]) are the same specimen, with different IGM hypotype numbers, of a so-called Propustularia kemperae from the Paleocene Sepultura Formation on the northwest flank of Mesa San Carlos, Baja California Sur, México. This specimen is very worn and/or weath- ered, and it cannot be identified with certainty.

Propustularia kemperae is similar to the middle Mio- cene P. neugeboreni ( Hoernes and Auinger, 1880: pp. 58, 59, pl. 7, figs. 5, 6) from Lapugy (= Lăpugiu de Sus), Romania. Dolin and Lozouet (2004: p. 60, pl. 27, figs. 3a–3c, 4), Fehse (2009: pp. 14, 53, fig. 38, pl. 14, fig. 1), and Lorenz (2017: p. 211; 2018, pl. 328, fig. 2) also fig- ured P. neugeboreni . Propustularia kemperae has much stronger and more laterally expansive sculpture on the base of its shell.

Lorenz (2017: p. 211) reported the geologic range of Propustularia to be Eocene to Holocene but based on new information concerning Propustularia kemperae , the earliest record of this genus is the Paleocene (Selandian Stage).