Galeodea meganosensis, VOKES, 1939

Squires, Richard L., 2022, Revision of Eocene warm-water cassid gastropods from coastal southwestern North America: implications for paleobiogeographic distribution and faunal-turnover, PaleoBios 36, pp. 1-22 : 4-7

GALEODEA MEGANOSENSIS VOKES, 1939

FIG. 3A–D

Galeodea sutterensis “Dickerson. ” Clark and Woodford, 1927. p. 113; pl. 19, fig. 21 [misidentification].

Galeodea sutterensis meganosensis Vokes, 1939 . p. 151; pl. 19, fig. 18.

Galeodea (Gomphopages) meganosensis Vokes. Durham, 1942 . p. 184. Squires, 1987. p. 39; fig. 49. Squires, 1988a. pl. 1, fig. 11.

Galeodea aff. nodosa carinata ( Deshayes, 1835) . Squires, 1988b. p. 13, figs. 30, 31.

Primary Type Material— Of G. meganosensis Vokes, 1939 , holotype UCMP 31244, Locality UCMP 3152, Meganos Formation, Deer Valley, Mount Diablo area, Contra Costa County, northern California. Holotype = the specimen misidentified as G. sutterensis “Dickerson ” Clark and Woodward.

Material examined— The ten specimens include: Plaster replica of holotype, hypotypes LACMIP 7474 , 7711 , 14829 , 14830 , and five unfigured specimens from LACMIP Locality 40827 .

Emended description— Shell small to medium size (up to 33 mm height, incomplete). Shape globose with small spire and large subquadrate last whorl. Spire relatively high, last whorl with two carinae; carina on shoul- der strongest with approximately 11 spinose tubercles; second carina noticeably weaker also with approximately 11 tubercles (rounded, not spinose) becoming weaker toward outer lip and unaligned relative to nodes on shoulder. Spiral thread with minute nodes can be present medially in interspace between carinae, and another spiral thread with minute nodes can be present anterior to second carina. Shell surface otherwise covered with very fine spiral threads, with cancellate patches. Anterior siphonal canal broken but shows twisting. Episodic varix uncommon but thick. Terminal varix narrowly thickened.

Stratigraphic occurrence— Lower Eocene, northern to southern California. “ Meganos Stage ”: Meganos Formation, Deer Valley, north side of Mount Diablo, Contra Costa County, northern California ( Vokes 1939, Clark and Woodward 1927). “ Capay Stage ”: Lodo Formation, Cerros Shale Member [=new information: UCMP locality 1817; for locality details, see Squires (1988c)], Urruttia Canyon, north of Coalinga, Fresno County, northern California. Lower Juncal Formation, Whitaker Peak, Los Angeles County, southern California ( Squires 1987). “ Domengine Stage ”: Juncal Formation?, northern Lockwood Valley, Ventura County, southern California ( Squires 1988b) [for age update, see Squires (2000)].

Remarks— Vokes (1939) recognized that Clark and Woodford (1927) misidentified a new gastropod as Galeodea sutterensis Dickerson,1916 . Vokes (1939) named this new gastropod G. meganosensis and regarded it to be a subspecies of G. sutterensis . Based on its less submerged spire, only two carinae (never three), more nodes, and shell covered otherwise with fine spiral threads, G. meganosensis is regarded herein a distinct species.

Figures

Figure 3. See caption on the bottom of page 7.