Echinophoria, SAcco, 1890

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 : 12

ECHINOPHORIA SAcco, 1890

Type species— By subsequent designation ( Dall, 1909), Buccinum intermedium Brocchi, 1814 . Oligocene and Miocene of Italy ( Abbott 1968: p. 96).

Geologic range— Middle Eocene to Recent. Echinophoria is present in middle Miocene to early Pliocene strata, as well as uncommonly in the modern record, in the Dominican Republic and elsewhere in the Caribbean Sea region ( Beu 2010).

Differential diagnosis— Spire height moderately low. Inner lip callus thin or absent and columellar callus absent; no false umbilici created by calluses. Aperture wide. Columella long, anterior siphonal canal strongly twisted, slightly to moderately notched, and fasciolate. Siphonal fasciole very distinct, with posterior edge of anterior canal noticeably producing two long “plica-like” spiral structures extending across ventral surface of siphonal canal and reaching notch area; siphonal fasciole separated from base of last whorl by distinct groove. Previous varices rare (on fossils), absent (on modern specimens). Episodic varices rare on fossils and very rare to absent on modern specimens. Terminal varix on outer lip thin to thickened and reflected ( Beu 2010: p. 231).

Remarks— Beu (2010: p. 242) gave six genus-groups names of Echinophoria . The protoconch of Echinophoria is low-turbiniform, with a well-impressed suture and about three strongly inflated, smooth whorls. Beu (2008, 2010) opined that Echinophoria , with its prominent sculpture resembling that of Galeodea , is likely to have been the stem group of the Phaliinae , evolving from Galeodea late in Cretaceous time.

Durham (1942) was the first to recognize the presence of Echinophoria in the CSWNA region, and he used Echinophoria species to help establish a cassid-biostratigraphic zonation scheme for the Pacific Northwest (PNW). This zonation was developed further and expanded by Armentrout (1975: pp. 18–25). Moore (1984) used the phylogeny of the phaliine genera Echinophoria and especially Liracassis for the purpose of also furthering the PNW cassid-biostratigraphic zones. Prothero and Armentrout (1985) used high-resolution, magnetostratigraphy for refining these zones, and this technique was utilized further by Prothero (2001: fig. 2), Prothero (2003: fig. 1.3), Nesbitt (2003: fig. 4.1), and Nesbitt et al. (2010) to update the cassid zonation. The Galeodea trituberculata zone, which includes the Cowlitz Formation and the tropical-Eocene fauna, is followed, in vertical stratigraphic succession, by the cooler water Echinophoria dalli , E. fax , and Liracassis zones ( Fig. 2). Liracassis is one of several genera that diverged from Echinophoria during the Cenozoic but is now extinct ( Beu 2008: p. 362). Echinophoria differs from Liracassis by having a smaller shell size, absence of strap-like spiral ribs, spiral ribbing never as dominant, nodes never as weak, longer and straighter anterior canal, and weaker development of longitudinal spiral cords on the anterior canal.