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 trochidsCidarina cretaceanew species andCidarina betanew species, the ficidBulbificopsis garzanew genus and new species, and the cancellariidMataxa aridanew species are from the Maastrichtian part of the Moreno Formation of north-central California. This is the earliest record ofCidarina, whose previous chronologic range was middle Eocene to Recent.Bulbificopsisis the first record of a Cretaceous ficid from the Pacific slope of North America, andMataxawas previously known only from Upper Cretaceous strata in the southeastern United States and northeastern Brazil. The buccinidEripachya jalamanew species and the fasciolariidCalkota daileyinew genus and new species are from the lower upper Campanian Jalama Formation in southern California.Calkotais also recognized herein as occurring in upper Maastrichtian strata of North Dakota and South Dakota. The new melongenid genus,Pentzia, established forFulgur hilgardiWhite, 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.

A fishy mosasaur: the axial skeleton of Plotosaurus (Reptilia, Squamata) reassessed

“…The material described and illustrated herein consists of both disarticulated and fully articulated skeletons collected from the Tierra Loma Shale and Garzas Sand member of the Moreno Formation, San Joaquin Valley, central California. On the basis of ammonites, gastropods and benthic foraminifers, the mosasaur‐bearing strata have been dated as late Early to early Late Maastrichtian (see Squires & Saul 2003 and references therein).…”

Northeast Pacific Cretaceous record ofPyropsis(Neogastropoda: Pyropsidae) and paleobiogeography of the genus

“…Current summaries of the geological details of nearly all the formations and members containing the study area Pyropsis can be found in the following papers (listed in ascending chronostratigraphic order): Hornbrook Formation, Osburger Gulch Member (Squires and Saul, 2003a); Tuna Canyon Formation, lower part (Alderson, 1988); and Redding Formation, Bear Creek Sandstone Member, Member IV, and Member V (Squires and Saul, 2003b). Comments pertaining to the occurrence of Pyropsis grahami n. sp.…”

Cretaceous opine bivalves from the Pacific slope of North America and palaeobiogeography of subfamily Opinae Chavan, 1969

“…Current summaries of the geological details of most of the formations and members containing study area opines can be found in the following papers (listed in ascending chronostratigraphic order): Frazier Siltstone, Melton Sandstone and Bear Creek Sandstone members of the Redding Formation (Squires and Saul 2003 a ); upper Baker Canyon Member of the Ladd Formation (Squires and Saul 2003 c ); Holz Shale Member of the Ladd Formation (Saul 1982); Haslam Formation (i.e. see under ‘Nanaimo Group) (Squires and Saul 2004 a ); Schulz Member of the Williams Formation (Filkorn 2007); Pigeon Point Formation (Squires and Saul 2003 b ); upper Cedar District Formation (Squires and Saul 2001; Squires and Saul 2006); Punta Baja Formation (Squires and Saul 2005); Gualala Formation (Squires and Saul 2004 b ); Point Loma Formation (Squires and Saul 2001) and ‘Garzas Sand’ and ‘Quinto Silt’ members of the Moreno Formation (Squires and Saul 2003 b ).…”