Paleolimnological inferences based on Oligocene ostracods (Crustacea: Ostracoda) from Tremembé Formation, Southeast Brazil

Abstract

Non-marine Oligocene ostracods from Tremembé Formation (Taubaté Basin, Southeast Brazil) are studied for the first time. The study reveals rich assemblages which are probably composed of many new taxa, two of which are described here. The sixteen ostracod species registered are classified in the genera Cypretta Vávra, Strandesia Stuhlmann, Potamocypris Brady, Heterocypris Claus, Eucypris Vávra, Herpetocypris Brady and Norman, Cytheridella Daday and Limnocythere Brady. Two new species of the latter are herein proposed: L. mandubi sp. nov. and L. katu sp. nov. The succession of ostracod assemblages along the studied core changes conspicuously in composition, abundance and preservation, and are characterized by the following associations: Herpetocypris-Cytheridella (lower), Limnocythere-Cypretta (middle) and Potamocypris-Heterocypris (upper). It is assumed that these associations represent different ecological phases of the paleolake Taubaté which is in accordance to previous stratigraphic and paleontological studies in the basin. The results from this pioneering taxonomic and paleoecological study on ostracods from Tremembé Formation reinforce the potential of these fossils for paleolimnological researches in Brazilian Cenozoic deposits.

New Oligocene Cyprididae species (Crustacea, Ostracoda) from the Tremembé Formation, Taubaté Basin, Brazil, and their paleolimnological significance

“…nov. to a younger and more unstable (shallow), or even temporary water bodies in the marginal area of the lake. These data reinforce previous interpretation by Bergue et al (2015b) related to the shallowing trend in the final deposition of the Tremembé Formation (Oligocene), toward the overlying Pindamonhangaba Formation (Late Miocene-Pliocene), during the fourth phase of development of basin (Cognè et al, 2013).…”

“…Brito & Ribeiro, 1975;Bernardes-de-Oliveira et al, 2002), yet it has never been studied. The first work published on ostracods of the Tremembé Formation was that by Bergue et al (2015b), who obtained some paleolimnological inferences based on the taxonomic study of 16 species. This implies that much is still to be done concerning the study of ostracods in this basin.…”

Morphological re-description and molecular characterization of Heterocypris salina (Brady, 1868), a new recorded ostracod species in Egypt.

“…Some authors recorded the presence of these tubercles in both the anterior and the posterior margins of the right valve of H. salina (Petkowski et al, 2000;Sars, 1928;Meisch and Broodbakker, 1993). However, the examination of the studied species recorded the presence of small 25 tubercles in the posterior edge of right valve only, which is agree with the observation of Bergue, et al (2015).…”

“…2-The first endite of Maxillula has blunt pilose, as well as four smooth setae and two biserrated setae while blunt pilose is disappeared in H. salina described by Kubanç et al(2007). Generally, the results of morphological study, when compared with previous studies (Meisch and Broodbakker 1993;Hollwedel and Scharf 1988;Petkowski et al, 2000;Meisch 2000;Kubanç et al, 2007;Karanovic 2012;Bergue et al 2015) implied that the studied species is H. salina, inspite of limited differences. These differences could be explained on the bases of that the genus Heterocypris is characterized by morphological plasticity which often is related to environmental factors (Benzie, 1984).…”

Ostracods, Charophytes, and Pollen from the Baynunah Formation

“…Taphonomy is an important source of non-taxonomic paleolimnological data (Bergue et al 2015). Degrees of carapace articulation, dissolution and preservation are particularly informative in ostracod assemblages (Cohen 1987).…”