Taxonomy of Deep-sea Trachyleberidid, Thaerocytherid, and Hemicytherid Genera (Ostracoda)

Abstract

of Deep-Sea Trachyleberidid, Thaerocytherid, and Hemicytherid Genera (Ostracoda). Smithsonian Contributions to Paleobiology, number 96, xii + 216 pages, 95 figures, 3 tables, 2015.-We conducted a comprehens ive systematic revision of deep-sea Trachyleberididae, Thaerocytheridae, and Hemicytheridae (Ostracoda, Crustacea) covering almost all Cenozoic genera using high-resolution scanning electron microscopy. Trachyleberididae, our main focus, is one of the most diverse and abundant ostracod families, but its genus-level taxonomy is still confusing. Approximately 700 specimens from 177 species from 47 genera were examined. The studied samples range in age from the Cretaceous to the present day and cover all major oceans in the world, including the Atlantic, Pacific, Indian, and Southern Oceans, the Mediterranean Sea, and the Gulf of Mexico. Five new genera and 45 new species are described:

Marine Ostracoda (Crustacea) from the Late Oligocene Gellibrand Marl, Otway Basin, Victoria, Australia

“…The comprehensive reassessment of the Trachyleberis genus by Brandão et al (2013) retained only 17 species (pending review of the many hundreds of taxa previously regarded as Trachyleberis). Yasuhara et al (2015) revised the taxonomy of deep-sea Trachyleberididae and erected four new genera. Their emended diagnoses of Actinocythereis, Cythereis and Trachyleberis removed the confusion over trachyleberids displaying varying degrees of spinous alignment.…”

“…Their emended diagnoses of Actinocythereis, Cythereis and Trachyleberis removed the confusion over trachyleberids displaying varying degrees of spinous alignment. The emended generic concept of Trachyleberis Brady (1898) by Brandão et al (2013) that required the genus to display an ocular ridge and internal snap-knob structure was further restricted by Yasuhara et al (2015) to only include species of the genus occurring in shallow marine areas of midlatitude northwestern Pacific (~20°N-40°N)" (Yasuhara et al 2015). Yasuhara et al (2015) emended the diagnosis for the Genus Cythereis Jones, 1849 to include many species previously placed in Trachyleberis, Glencoeleberis, Taracythere, Acanthocythereis, Actinocythereis and Cytherina.…”

“…The emended generic concept of Trachyleberis Brady (1898) by Brandão et al (2013) that required the genus to display an ocular ridge and internal snap-knob structure was further restricted by Yasuhara et al (2015) to only include species of the genus occurring in shallow marine areas of midlatitude northwestern Pacific (~20°N-40°N)" (Yasuhara et al 2015). Yasuhara et al (2015) emended the diagnosis for the Genus Cythereis Jones, 1849 to include many species previously placed in Trachyleberis, Glencoeleberis, Taracythere, Acanthocythereis, Actinocythereis and Cytherina. Their diagnostics for Cythereis are: amphidonttype hinge; shallow, often indistinct primary reticulation (with some exceptions); distinct ventero-lateral ridge continuing into the anterior marginal rim; generally well developed subcentral tubercle; distinct anterior and posterior marginal rims; absence of ocular ridge; V-shaped frontal scar; no internal snap-knob structure at ventral midlength; subtriangular-subtrapezoidal outline; presence of eye tubercle not a requirement (Yasuhara et al 2015).…”

Ecology, palaeontology and taxonomy of Echinocythereis Puri, 1954 (Crustacea: Ostracoda) with a focus on the North Atlantic species

“…Yasuhara et al . (in press, fig. 48.T–48.U) studied the specimens labelled as ‘topotype of Echinocythereis garretti’ from the ‘type locality, Middle Miocene’ housed in the National Museum of Natural History Museum (Smithsonian Institution, Washington DC, USA) collection (number P3287).…”

“…However, based on their excellent SEM photographs, the Recent specimens from the Gulf of Mexico (Yasuhara et al . in press, fig. 48.P–48.S) are conspicuously more circular, and less elongated than the topotypes of E. garretti (their fig.…”