Louella R. Saul

A NEW GENUS OF CRYPTIC LUCINID? BIVALVE FROM EOCENE COLD SEEPS AND TURBIDITE-INFLUENCED MUDSTONE, WESTERN WASHINGTON

LOUELLA R. SAUL, RICHARD L. SQUIRES, AND JAMES L. GOEDERT Natural History Museum of Los Angeles County, 900 Exposition Boulevard, Los Angeles, California 90007, Department of Geological Sciences, California State University, Northridge 91330-8266, and 15207 84th Avenue Ct. NW, Gig Harbor, Washington 98329-8765 and Museum Associate, Vertebrate Paleontology, Natural History Museum of Los Angeles County

NEW LATE CRETACEOUS GASTROPODS FROM THE PACIFIC SLOPE OF NORTH AMERICA

Abstract Two new genera and ten new species of shallow-marine, warm-water gastropods are reported from several Upper Cretaceous formations found between British Columbia and southern California. The buccinid Zaglenum new genus is represented by two new species and the turbinellid Fimbrivasum new genus is represented by three new species. The nododelphinulid Trochacanthus pacificus new species is the first record of this genus in the Western Hemisphere, and the procerthiid Nudivagus? califus new species could be the first record of this genus on the Pacific slope of North America. The xenophorid Xenophora (Endoptygma) hermax new species is only the second known Cretaceous species of this genus on the Pacific slope of North America, and this species establishes that Endoptygma Gabb, 1877, is a valid taxon. The neritid Otostoma sharonae new species is only the fourth known Cretaceous species of this genus on the Pacific slope of North America. The ringiculid Ringicula? (Ringiculopsis?) hesperiae new species is the first Campanian record of this genus on the Pacific slope of North America and the first recognition of this subgenus in this area.

NEW LATE CRETACEOUS (CAMPANIAN AND MAASTRICHTIAN) MARINE GASTROPODS FROM CALIFORNIA

Abstract Three new genera and six new species of shallow-marine gastropods are named from Upper Cretaceous strata found mainly in California. The trochids Cidarina cretacea new species and Cidarina beta new species, the ficid Bulbificopsis garza new genus and new species, and the cancellariid Mataxa arida new species are from the Maastrichtian part of the Moreno Formation of north-central California. This is the earliest record of Cidarina, whose previous chronologic range was middle Eocene to Recent. Bulbificopsis is the first record of a Cretaceous ficid from the Pacific slope of North America, and Mataxa was previously known only from Upper Cretaceous strata in the southeastern United States and northeastern Brazil. The buccinid Eripachya jalama new species and the fasciolariid Calkota daileyi new genus and new species are from the lower upper Campanian Jalama Formation in southern California. Calkota is also recognized herein as occurring in upper Maastrichtian strata of North Dakota and South Dakota. The new melongenid genus, Pentzia, established for Fulgur hilgardi White, 1889, is from Campanian strata throughout California; middle Campanian strata on Sucia Island, Washington; and upper Campanian to lower Maastrichtian strata in northern Baja California, Mexico.

NEW CRETACEOUS CERITHIFORM GASTROPODS FROM THE PACIFIC SLOPE OF NORTH AMERICA

Abstract Two new genera and three new species of shallow-marine, warm-water gastropods are reported from outcrops of various Cretaceous formations between British Columbia and Baja California. The potamidid Cedrosia pacifica new genus and species is from Turonian strata on Cedros Island, west coast of Baja California, Mexico. It is the earliest potamidid known from the rock record of the Pacific Slope. Alamirifica corona new genus and species, whose suprageneric relationships are uncertain, is from Turonian strata in southern California. The holotype has a round and rimmed aperture most similar to the photine buccinid Neoteron Pilsbry and Lowe, 1932. The holotype also has a pyramidal spire most similar to some fossil cerithioideans traditionally placed in the potamidid Pyrazus Montfort, 1810, but the type species of Pyrazus does not have a pyramidal spire. Future work might reveal that Alamirifica belongs to a new family. Four other Pacific Slope species are tentatively assigned to Alamirifica: the Aptian A.? harrissi (Allison, 1955); the Coniacian A.? ursa new species; the late Coniacian to early Campanian A.? harveyi (Whiteaves, 1903); and the poorly preserved Turonian Alamirifica? sp. As presently known, Cedrosia and Alamirifica were endemic to the study area, but they strongly resemble some Old World Tethyan gastropods. The distribution of A.? harveyi lends support to a relatively northern site of deposition for the Nanaimo Group.

Review of the bivalve genus Plicatula from Cretaceous and lower Cenozoic strata of California and Baja California

The Cretaceous and early Cenozoic species of the shallow-marine, warm-water bivalve Plicatula from California (United States) and Baja California (Mexico) are reviewed, and three new species are named. All of these species are representatives of Plicatula and not of the closely related taxon Harpax, which is associated with high-latitude and cool-water regions. The earliestknown Cretaceous species of Plicatula from the study area is P. variata Gabb, 1864, from Lower Cretaceous (Hauterivian Stage) strata in northern California, and our studies show it to be conspecific with Plicatula onoensis Anderson, 1958. Plicatula allisoni new species is from Lower Cretaceous (Albian Stage) strata in Baja California, Mexico. Plicatula modjeskaensis new species is from Upper Cretaceous (Turonian Stage) strata in the Santa Ana Mountains, southern California. A possible new species from the same strata is also mentioned. A poorly preserved specimen of Plicatula ? sp. is known from Upper Cretaceous (upper Campanian to lower Maastrichtian) strata in northern California. The only Paleocene species of Plicatula from the study area is P. ostreiformis Stanton, 1896, from lower Paleocene strata of Lake County, northern California, and our studies show it to be conspecific with Ostrea buwaldana Dickerson, 1914. The only previously described Eocene species of Plicatula from the study area is P. juncalensis Squires, 1987, from lower middle Eocene (“Capay Stage”) strata of Los Angeles County, southern California. Plicatula surensis new species is from middle lower Eocene (“Capay Stage”) strata in Baja California Sur, Mexico. In addition, there is a Plicatula ? sp. from Eocene strata of Baja California Sur, Mexico. Although Plicatula is of uncommon occurrence north of Baja California, its thermophilic trait makes it useful in recognizing periods of warm climate.

Volutoderminae (Gastropoda: Volutidae) of Coniacian Through Maastrichtian Age from the North American Pacific Slope

Abstract Specimens of the large, shallow-marine, volutid gastropod Volutoderma Gabb, 1877, herein recognized only from strata of Late Cretaceous (Coniacian through early Maastrichtian) age in British Columbia, Washington, California, and Baja California have commonly been identified as Volutoderma averillii (Gabb, 1864). This review of available specimens assigns them to two genera: Volutoderma and Longoconcha Stephenson, 1941. Twelve species, nine of them new, comprise three morphologic lineages of Volutoderma, i.e., 1) “Typical” includes V. querna n. sp., V. averillii (Gabb), V. blakei n. sp., V. jalama n. sp., V. perissa n. sp., and possibly Volutoderma? n. sp.; 2) “Angelica” includes V. angelica n. sp., V. elderi n. sp., and V. ynezae n. sp.; and 3) “Magna” includes V. santana Packard, V. magna Packard, and perhaps V.? antherena n. sp. A new species of Longoconcha, L. eumeka, is the first Pacific Slope record of this genus, which has a Gulf Coast and Tethyan Old World distribution. A smaller volutid, Retipirula Dall, 1907 is endemic to the study area and was formerly known only from its type species R. crassitesta (Gabb, 1869) of Paleocene age. Two new Retipirula are reported: R. calidula of latest Maastrichtian age and R. pinguis of Paleocene age. Only the Volutoderma lineage containing V. averillii has been found north of San Francisco. Recovery of rudist bivalves from formations yielding Volutoderma suggests that these volutes were warm-temperate to subtropical gastropods. Co-occurrences of these gastropods and rudistids may aid in placing the warm-temperate/subtropical boundary during the Late Cretaceous.

THE PSEUDOMELANIID GASTROPOD PAOSIA FROM THE MARINE CRETACEOUS OF THE PACIFIC SLOPE OF NORTH AMERICA AND A REVIEW OF THE AGE AND PALEOBIOGEOGRAPHY OF THE GENUS

Abstract The Pacific Slope of North Americas paleontologic record of Paosia, a nearshore-marine, pseudomelaniid gastropod primarily associated with the Old World Cretaceous Tethyan realm, is established for the first time. Former workers have almost universally referred to this genus by its junior synonym name Trajanella Popovici-Hatzeg, 1899. Six species, including Paosia pentzensis new species, are recognized, and all are from siliciclastic facies. Their documentable geologic range is late early Albian to early Campanian. Four of the five previously named species were misallocated to genus Acteonina and one was placed in genus “Trajanella.” Paosia originated in western Europe and in the Caucasus Mountains region during the latest Jurassic (Tithonian). It arrived in the study area, possibly in the Aptian, but certainly by the late early Albian and, most likely, by way of Japan and the north Pacific gyre. Worldwide, the genus had its peak diversity during the Albian and Cenomanian. The only other Western Hemisphere records of Paosia are a species from the Campanian of Jamaica and a possible species from the Coniacian of Texas. Paosia had a preference for tropical waters, but its presence in the study area indicates that it could live in temperate-tropical transition areas. Most of the Pacific Slope of North America species are represented by a few specimens, but when plentiful, they display variability in overall shape between juvenile and adults, with the last whorl of the adults becoming more cylindrical with growth. Paosia kollmannii new name is proposed for the homonym Trajanella acuminata Kollmann, 1979.

New upper Paleocene species of the bivalve Plicatula from Southern California

Three new species of the shallow-marine, warm-water bivalve Plicatula are reported from the upper Paleocene Santa Susana Formation of southern California. Plicatula simiensis new species is from the middle part of the formation on the south side of Simi Valley and occurs as a displaced specimen in deep-marine turbidites. Plicatula lapidicina new species and P. trailerensis new species are both from coralline-algal-rich muddy siltstone just beneath a nearshore, coralline-algal limestone interval in the upper part of the formation in the Santa Ynez Canyon area, east-central Santa Monica Mountains. These three new species represent the first late Paleocene records of genus Plicatula on the west coast of North America and the first Paleocene records of this genus in southern California.

NEW EARLY LATE CRETACEOUS (CENOMANIAN) MOLLUSKS FROM OREGON

Abstract Four new molluscan species, a bivalve and three gastropods, are named from shallow-marine, lower Upper Cretaceous (Cenomanian Stage) strata in Oregon. The laternulid bivalve Cercomya (Cercomya) hesperia new species is from the Bernard Formation in east-central Oregon and from the Osburger Gulch Sandstone Member of the Hornbrook Formation in southwest Oregon. It is the first Cenomanian record of this genus. The iteriid gastropods, Vernedia pacifica new species and Sogdianella oregonensis new species, are from unnamed Cenomanian strata in east-central Oregon and represent the first records of these genera in western North America. The actaeonellid gastropod Trochactaeon (Neocylindrites) allisoni new species from these same deposits represents the first record of this genus in Oregon. The new species of Cercomya sensu stricto, Vernedia, and Neocylindrites are very similar to western European species, and the new species of Sogdianella is most similar to a Peruvian species.