Grovesia mathewsonii, (GABB, 1869)

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 : 31-33

GROVESIA MATHEWSONII ( GABB, 1869)

FIGS. 9C–L

Cypraea (Epona) mathewsonii Gabb, 1869 . pp. 164 [as C. (E.) Mathewsonii], 225 [as C. (Epona) Mathewsonii ], pl. 27, figs. 44a, b; Cooper, 1888. p. 280; Arnold, 1906. p. 15; Keen and Bentson, 1944. p. 152 [in part].

Cypraea mathewsonii Gabb. Campbell, 1892 . p. 51. Whiteaves, 1895 [as C. Mathewsonii ]. p. 128 (as mathewsoni ). Dickerson, 1915. pp. 43, 60, pl, 6, fig. 5a. Dickerson, 1916. pp. 421, 438, 448. Anderson and Hanna, 1925. pp. 43, 106, 107; Nelson, 1925. p. 425 (as mathewsoni ). Stewart, 1926 [1927]. p. 371, pl. 28, fig. 5; Ingram, 1942. p. 105, pl. 9, fig. 12; Ingram, 1947a. p. 61, pl. 7, fig. 10. Ingram, 1947b. p. 147; Weaver, 1953. p. 43; Richards, 1968. p. 156.

Cypraea kerniana Anderson and Hanna, 1925 . pp. 44, 104, 105, 107, pl. 13, figs. 9–11. Clark, 1926. p. 115 (as Cyprea ). Stewart, 1926 [1927]. p. 371. Hanna, 1927. pp. 249, 259, 314, pl. 52, figs. 7, 9. Keen and Bentson, 1944. p. 152.

Sulcocypraea mathewsonii (Gabb) . Schilder, 1927. p. 81; Schilder, 1941. p. 104. Groves, 1992. p. 106. Fehse, 2001. p. 22.

Sulcocypraea mathewsonii mathewsonii (Gabb) . Schil- der, 1932. p. 222 (in part) [as S. mathewsonii mathewsonii ]. Schilder and Schilder, 1971. pp. 68 [as Sulcocypraea mat . mathewsonii ], 131. Fehse, 2021. p. 44.

Sulcocypraea kerniana (Anderson and Hanna) . Schil- der, 1932. p. 222 [as S. kerniana ]. Schilder, 1941. p. 104; Schilder and Schilder, 1971. p. 68, 125; Dolin and Dolin, 1983. p. 44.

Cypraea sp. B , Turner, 1938. pp. 19, 35.

Erato mackini Durham, 1944 . pp. 117, 165, 166, pl. 18, figs. 7, 9.

Cypraea sp. B , n. sp. (sp. B of Turner?), Hoover, 1963. p. D-27.

Eratotrivia mackini (Durham) . Schilder and Schilder, 1971. pp. 10, 129.

Luponovula mathewsonii (Gabb) . Dolin and Dolin, 1983. pp. 42–44, 46 (table 1), figs. 28, 29a–c. Dolin and Ledon, 2002. p. 344. Not Grovesia mathewsonii [= G. ganensis Dolin and Ledon, 2002 ].

Sulcocypraea mathewsonii (Gabb) . Squires and Groves, 1993. figs. 2–4. Not Grovesia mathewsonii ( Gabb, 1869) = G. castacensis ( Stewart, 1926 [1927]). Groves and Squires, 2018. p. 88. Groves and Squires, 2021. p. 227 (as Cypraea ).

Prionovolva (Grovesia) mathewsonii (Gabb) . Dolin and Ledon, 2002: pp. 335, 336.

Grovesia mathewsonii (Gabb) . Dolin and Pacaud, 2009: p. 289.

Holotypes and Type Localities— Of G. mathewsonii , holotype ANSP 4217 (Figs, 9C–E), length 10.4 mm, width 7.0 mm, height 5.9 mm, Muir Sandstone near Martinez, Contra Costa County, northern California ( Squires and Groves 1993). Of G. kerniana , holotype CASG 245.02 [ex CASG 816] (Figs. 9F–G), length 17.3 mm, width 11.8 mm, height 9.1 mm, CASG Locality 245, Tejon Forma- tion, Grapevine Creek, Tehachapi Moutains, Kern County, southern California. Of Erato mackini , holotype UCMP 35337, length 9.6 mm, width 7.1 mm, UCMP Locality A1802, Lincoln Creek Formation, Discovery Bay, Jefferson County, Washington ( Durham 1944).

Paratypes — Of G. kerniana : CASG 245.03 (ex CASG 817), length 14.9 mm, width 12.4 mm, height 9.9 mm and CAS 245.04 [ex. CASG 818] length 13.8 mm, width 10.2 mm, height 8.4 mm. Both from CASG Locality 245, Grapevine Creek, Kern County, southern California. Of Erato mackini , two paratypes UCMP 35338 and 35339, both from UCMP Locality A1802, Lincoln Creek For- mation, Discovery Bay, Jefferson County, Washington ( Durham 1944).

Referred Specimens—Hypotype (of Dickerson, 1915: pl. 6, fig. 5) CASG 66608.01 (ex CASG 298 ) , length 16.7, width 12.1 mm, height 9.8 mm, CASG Locality 66608 (= CASG Locality 245), Tejon Formation , Grapevine Can- yon, Kern County, California. Hypotype (of Hanna, 1927: pl. 52, figs. 7, 9 as Cypraea kerniana , as plesiotype) UCMP 30903 (Figs, 9K–L) , length 14.3 mm, width 10.2 mm, height 8.4 mm, UCMP Locality 5085, Ardath Shale , San Diego County, southern California. Hypotype (herein) LACMIP 7155.9 , LACMIP Type 14930 (Figs. 9H–J), LAC- MIP Locality 7155 [ex CIT Locality 707], Tejon Formation, Grapevine Canyon , Kern County, southern California (10 additional unfigured specimens ( LACMIP 7155.10 ) . Additional material examined: LACMIP Localities 7162 [ex CIT Locality 1840] (four specimens, LACMIP 7162.2 , LACMIP Type 14931) , LACMIP Locality 22340 [ex UCLA Locality 2340] (13 specimens, LACMIP 22340.52 , LAC- MIP Type 14932) and LACMIP Locality 43272 (two speci- mens, LACMIP 43272.1 , LACMIP Type 14933), all Tejon Formation, Grapevine Canyon , Kern County, California. One additional specimen ( LACMIP 43273.1 , LACMIP Type 14943) from LACMIP Locality 43273 (= UWBM Locality A 7561), Tukwilla Formation, Poverty Hill area , King County, Washington collected by J.L. Goedert was examined is identified as Grovesia cf. mathewsonii but could represent an undescribed species .

Occurrence— Upper lower to middle upper Eocene, southwestern Washington, southwestern Oregon to southern California. “Domengine Stage”: Tyee Forma- tion, Drain/Comstock area north of Roseburg, south- western Oregon ( Turner 1938). Ardath Shale, San Diego region, San Diego County, southern California ( Hanna 1927). “Tejon Stage” (lower part): Tejon Formation, Li- veoak Member, Grapevine Canyon, Tehachapi Mountains, Kern County, southern California ( Dickerson 1915, 1916; Anderson and Hanna 1925; present report). Galvinian Stage ( Molopophorus stephensoni zone): Lincoln Creek Formation, northern part of southwestern Washington ( Durham 1944). According to Armentrout (1974: p. 37, fig. 2, the M. stephensoni zone is correlative to the middle Galvinian Stage.

Etymology— Originally named for fossil collector Mr. Mathewson (Martinez, Contra Costa County, central California).

Description— Shell small, mostly smooth, moderately low convexity, and left-lateral side can be more inflated than right-lateral side (thereby producing “lop-sided” shape). Spire concealed by callus. Posterior end of shell protruding somewhat. Aperture fairly straight, widening anteriorly, and curved posteriorly. Outer lip teeth few (9 to 10), moderately strong, and widely separated. Inner lip teeth numerous, very small, and closely spaced. Basal surface with transverse ribs, variable in strength and number and not extending very far.

Remarks— At least 40 specimens of G. mathewsonii are documented here (see above) and undoubtedly many others exist in stratigraphic collections. The anterior end of the holotype is missing, and the preservation of the dorsum of the specimen is very poor. The basal view of the holotype of G. mathewsonii , with its distinctive lop-sided shell, is shown here for the first time (Fig. 8O). Additional specimens of G. mathewsonii (other than the type specimens of kerniana ) from the Tejon Formation are also shown here also for the first time. Some worn specimens of mathewsonii appear to not have any spiral ribs on their base, but very low-angle lighting reveals their presence (e.g., see Fig. 9C).

As noted above, there has been considerable confusion in the literature concerning the identification of Grovesia mathewsonii versus G. castacensis . This confusion is most certainly related to their both being found in the Tejon Formation in Kern County, southern California. It is im- portant to mention, however, that Grovesia mathewsonii occurs in the Liveoak Member of the Tejon Formation, whereas G. castacensis occurs in the stratigraphically overlying (i.e., younger; see Nilsen 1987) Metralla Mem- ber of the Tejon Formation. Grovesia mathewsonii differs from G. castacensis by having transverse ribs on the base and by having a lop-sided shell.

Anderson and Hanna (1929) mentioned localities containing “cowries” in the lower part of the Tejon For- mation in the Grapevine Canyon, Kern County, southern California. Most of these localities were demolished, however, by the subsequent building of and widening projects of Interstate 5 highway along the valley floor of this canyon. Fortunately, many well preserved specimens from this area were deposited at CIT, UCLA, and LACMIP by early collectors. Analysis of these specimens by the authors of this present report allowed for confirmation of G. mathewonsii as being present in the lower part of the Tejon Formation in Grapevine Canyon.

The holotype of kerniana (see Fig. 9B-C) is the same specimen figured by Anderson and Hanna (1925: pl. 13, fig. 9). When compared to the image available online ( CASG website), however, the holotype of G. kerniana looks quite different as a large piece of the columellar base is missing.

Based upon careful examination of Erato mackini Dur- ham, 1944 images, this species is herein relegated to the synonymy of Grovesia mathewsonii as the holotype and two paratypes are worn specimens of G. mathewsonii . They are significant specimens, however, as they repre- sent the geologically youngest and farthest north known occurrence of G. mathewsonii .

Turner (1938: pp. 19, 35) in faunal lists included Cypraea sp. B , length 14.8 mm, width 9.0 mm, height 7.4 mm, from the middle Eocene (“Domengine Stage”) Tyee Formation near Comstock near Drain, which is north of Roseburg, Oregon (Fig. 1, locality 8) (= UCMP Locality A-1134). Squires and Groves (1993: p. 83) identified Cypraea sp. B as Sulcocypraea mathewsonii ( Gabb, 1869) , but in the present report this taxon is identified as Grovesia mathewsonii ( Gabb, 1869) .

Dolin and Dolin (1983: table 1) erroneously reported G. mathewsonii , which they identified as Luponovula mathewsonii (Gabb) in France and Italy. Dolin and Ledon (2002: pp. 335, 336) noted that G. mathewsonii and G. ganensis Dolin and Leon (2002) are close morphological- ly, but they are not conspecific. Dolin and Pacaud (2009: p. 289), furthermore, reported that Grovesia is a distinct genus, and this assignment is used in this present report.