Galeodea sutterensis, DICKERSON, 1916

Squires, Richard L., 2019, Revision of Eocene warm-water cassid gastropods from coastal southwestern North America: implications for paleobiogeographic distribution and faunal-turnover, PaleoBios 36, pp. 1-22 : 7-8

GALEODEA SUTTERENSIS DICKERSON, 1916

FIG. 3E–M

Galeodea sutterensis Dickerson, 1916 . p. 492; pl. 40, figs. 1a, 1b. Schenck, 1926. p. 84, figs. 1, 2 (both refig- ured from Dickerson 1916). Vokes, 1939. p. 150; pl. 19, fig. 15. Turner, 1938. p. 92; pl. 18, fig. 19. Schenck and Keen, 1940. pl. 12, figs. 3, 4. Weaver, 1942. p. 402; pl. 78, figs. 6, 7.

Galeodea susanae Schenck, 1926 . p. 85; pl. 15, figs. 3–7. Turner, 1938. p. 92; pl. 18, fig. 18. Schenck and Keen, 1940. pl. 12, figs. 5, 6. Weaver, 1942. p. 402; pl. 78, figs. 2, 3.

Galeodea (Gomphopages) susanae Schenck. Durham, 1942 . p. 184. Givens, 1974. p. 78; pl. 8, fig. 4. Squires, 1984. p. 27; fig. 7k.

Galeodea (Gomphopages) sutterensis Dickerson. Durham, 1942 . p. 184; pl. 29, fig. 2. Givens, 1974. p. 78; pl. 8, fig. 4.

Galeodea cf. G. susanae Schenck. Givens and Kennedy, 1979 . p. 86.

Galeodea sp. Squires and Demetrion, 1992. p. 32; fig. 85.

Galeodea (Mamabrina) [sic] susanae Dickerson. Squires, 2008 . fig. 24.

[non] Galeodea sutterensis Dickerson. Clark and Woodford, 1927 . pl. 19, fig. 21 [= Galeodea meganosensis ].

Primary Type Material— Of G. sutterensis , holotype UCMP 11782 , Locality UCMP 1853 , Capay Shale, Sutter Buttes (= Marysville Buttes ), Sutter County, northern California . Of G. susanae , holotype CASG 1753 , Locality CASG 372 , Llajas Formation, north side Simi Valley , southern California ; paratypes CASG 1754 , 1755 , Llajas Formation ; paratype CASG 1756 , Lookingglass Formation, Glide , Douglas County, southwestern Oregon .

Material examined— The forty-two specimens include: Hypotypes LACMIP 13425, 14831-14833, and the following unfigured specimens: one from LACMIP Locality L1165, two from LACMIP Locality 2777, three from LACMIP Locality 7206, four from LACMIP Locality 7207,ten from LACMIP Locality7210, three from LACMIP Locality 22362, and fifteen from LACMIP Locality 40371.

Emended description— Shell small to medium size (up to 55 mm high, complete). Shape globose with small spire and large subquadrate last whorl. Protoconch small and smooth, naticoid, about three whorls. Teleoconch about 3.5 large whorls. Spire partly submerged. No sutural cord. Penultimate whorl commonly unevenly submerged. Last whorl subquadrate, spiral sculpture much stronger than axial sculpture, with posterior two-thirds of whorl having widely spaced two or, less commonly, three carinae (anteriormost carina can become obsolete toward the outer lip). Carinae bear tubercles, either spinose and long or, less commonly, narrow; tu- bercules unaligned between rows; carina on shoulder with 7 to 12 nodes. Teleoconch covered by numerous, closely spaced fine spirals, not necessarily minutely cancellate; fine spirals can alternate in strength and can be strongest on last whorl neck. Inner lip and columellar lip callus merge, with resultant callus extensive, project- ing laterally short distance, creating two false umbilici (one adjacent to neck and one adjacent to anterior end of canal). Neck constricted. Anterior canal long, slender, reflected sideways (laterally to the left) approximately 42°, and unnotched. Aperture moderately wide but constricted (grooved) at posterior end. Episodic varices normally lacking. Terminal varix narrow or phlange-like refection with exterior and interior smooth.

Stratigraphic occurrence— Lower to middle Eocene, southwestern Oregon to Baja California Sur, Mexico. “ Capay Stage ”: Lookingglass Formation, Douglas County, southwestern Oregon ( Turner 1938; Weaver 1942); Capay Shale, Sutter Buttes, Sutter County, northern California ( Dickerson 1916); Lodo Formation, Cerros Shale Member, Urruttia Canyon, north of Coalinga, Fresno County, northern California ( Vokes 1939) [ UCMP Locality 1817, for updated locality details, see Squires (1988c)]; Juncal Formation, Pine Mountain area, Ventura County, southern California ( Givens 1974); Juncal Formation, Whitaker Peak (near basement contact), Los Angeles County, southern California ( Squires 1987); Juncal Formation, Elsmere Canyon, Los Angeles County, southern California ( Squires 2008). Maniobra Formation (near basement contact), Orocopia Mountains, Riverside County, southern California ( Squires and Advocate 1986; Squires 1991); Bateque Formation, Baja California Sur, Mexico ( Squires and Demetrion 1992). “ Domengine Stage ”: Domengine Formation, Coalinga area, San Benito County, northern California ( Vokes, 1939). Llajas Formation (shallow-marine [transgressive] facies), Devil Canyon, Santa Susana Mountains, just east of northern side of Simi Valley, Los Angeles County, southern California ( Schenck 1926; Squires 1984). Ardath Shale, San Diego, San Diego County, southern California ( Givens and Kennedy 1979). Juncal Formation?, northern Lockwood Valley, Ventura County, southern California ( Squires 1988b) [for age update, see ( Squires 2000)]. “ Tejon Stage ”: Tejon Fm, probably Liveoak Member [=including new information: LACMIP Locality 22340; for locality details, see Squires (1989: appendix)], Tehachapi Mountains, Kern County, southern California.

Remarks— Galeodea sutterensis and G. susanae are considered to be synonyms because of their closely similar morphology, which is not unique to either one. Galeodea sutterensis , which has been reported previously from lower Eocene (“Capay Stage”) strata, commonly has three rows of spiral nodes on the last whorl. Galeodea susanae , which has been reported previously from middle Eocene (“Capay/Domengine” boundary strata and “Domengine Stage”) strata, commonly has two rows of spiral nodes on the last whorl. Galeodea susanae , however, can have three spiral rows ( Fig. 3 K-M).

The anterior canal is broken on all known specimens of G. sutterensis , except for a single specimen from the middle Eocene Llajas Formation in northern Simi Valley, southern California. This specimen, which has retained its long anterior canal ( Fig. 3H–J ), is remarkably similar to Galeodea turneri Gardner (1939: p. 25 , pl. 8, figs. 1, 4) from lower Eocene strata in Bastrop County, Texas. Galeodea sutterensis differs by having a less submerged spire and a ramp without weak to moderately weak axial ridges extending to each node on the shoulder of the last whorl.

Galeodea sutterensis is recognized herein for the first time in the Tejon Formation. It co-occurs there with the cassid Echinophoria trituberculta ( Weaver, 1912) at LACMIP Locality 22340. The Tejon Formation G. sutterensis specimens are small-medium in size (up to 38 mm height) and can have good preservation, except they are incomplete and most consist of large fragments of the last whorl with widely spaced spines.

Figures

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