168. On Estherites, new genus

Abstract

Fossil estherids are so similar to Posidonia and a few other genera of Pelecypoda that they are easily mistaken, but when well preserved, they can readily be distinguished from the pelecypodgenera by their shell-substance, absence of hinge teeth as well as adductor scars and notably by their surface sculpture. Futhermore, BILL and WRIGHT reported the soft parts of Estheria minuta (?) and Limnestheria adra respectively through which the conchostracan nature of the fossil esthrids was thoroughly proved.
Unfortunately, however, Estheria RUPPEL, 1837, cannot be used because it is preoccupied by Estheria ROBINEAU-DESVOIDY, 1830. Likewise, Isaura JOLY, 1841, is preoccupied by Isaura SAVINGNY, 1817. When DADAY classified the living estherids into 5 families and 11 genera, Estheria dahalacensis RÜPPEL, the type of Estheria, was referred to Leptestheria.
There are no less than eleven fossil-genera which have been referred to the Limnadidae or Estheriidae, but Estheria is the only genus which is quite similar to living estherids, especially to caenestherids, cyzicids and leptestherids. While leptestherids generally have reticulated sculptures, cyzicids and caenestherids more commonly possess puncated or granulated ones. However neither one of these sculptures can be used for the generic distinction of the groups, and accordingly Estheria cannot be replaced by any living genus. Therefore Estherites is proposed here to be used for fossil Estberia, and Estheria mitsuishii KOBAYASHI and HUZITA, 1942, is selected for the type of Estherites.