Middle Eocene Ostracoda from Baja California Sur, Mexico

Abstract

One genus and six new species of ostracodes are described from the Bateque Formation on the Pacific Coast of Baja California Sur, Mexico. Planktonic foraminifers indicate a mid Eocene age and the whole assemblage is characteristic of a shallow warm-water environment. Paijenborchella rnezquitalensis sp. nov. is the second record of the genus Puijenborchella from the Eocene of North America. Except for this species and the new genus Bujacythere, the ostracode association has strong affinities with those described from the lower Tertiary Gulf Coast region. 1. Micropalaeontol. 12 (2): 141-153, December 1993.

A new species of Cythere (Ostracoda) from the Middle Eocene McIntosh Formation, Doty Hills, Washington State, USA, and its significance for the evolutionary history of the genus

“…(2007); 15, Keen(l978); 16, Keij (1957), Guernet (1984), Ducasse et ai. (1985); 17, Szczechura (1977), Monostori (1996);18, Howe (1951); 19, Howe and Chambers(1935) , Stephenson (1944Stephenson ( ,1946, Krutak (1961), Huff (1970); 20, van den Bold(l960); 21, Neufville (1979); 22, Carreno and Cronin (1993); 23, Marianos and Valentine(l958); 24, Hazel and Holden (1971); 25, Ayress (1995); 26, Hornibrook (1953), McKenzie et ai. (1991McKenzie et ai.…”

Biostratigraphy and depositional history of the tepetate formation at Arroyo Colorado (Early-Middle Eocene), Baja California Sur, Mexico

“…The Ostracoda, with the exception of Jugosocythereis monrealensis, a species recognized as related to shallow, warm and temperate seas (Carreño and Cronin, 1993), could not be identified to a specific level. However, most of the genera are robust, highly calcified, ornamented forms ( Pokornella, Trachyleberis and Ambocythere), morphotype indicative of neritic biofacies.…”

Neohornibrookella sorrentae (Chapman and Crespin, 1928) and allied ostracod taxa from the Neogene of southeastern Australia: Systematic and palaeoceanographical relationships, palaeoecology and palaeobiogeography

“…A number of species that possess relatively subdued ornamental features, such as surface ridges, might also belong in this first Hermanites species group. For instance, the species Hermanites batequensis Carreño and Cronin, 1993 from the Eocene of the Pacific coast of Mexico lacks a clear dorsal ridge and posterodorsal loop but is otherwise very similar in general shape and ornamentation to H. cf. H. fungosa (sensu Benson, 1972).…”

“…These occurrences are probably a reflection of increased mid Pliocene, mid-high latitude global warming (e.g. Cronin et al, 1993;Knies et al, 2002). Significant mid Pliocene warming has been related to increased meridional oceanic heat transport associated with stronger thermohaline circulation, which enhanced sea ice retreat and caused a consequent decrease in high latitude albedo (Dowsett et al, 1992;Raymo et al, 1996).…”