A new genus, Tuberocandona gen. nov. (Crustacea, Ostracoda, Candonidae) and past to present ostracod species diversity in Texas (USA)

Abstract

A new ostracod genus, Tuberocandona gen. nov., was collected from Honeycut Hollow Springs, Texas, USA Morphological comparisons and cladistic analyses showed that the new genus displays several different features (e.g. presence of two tubercules on each of the valves, numbers of A1 segments, shape of A2 claws, shape and presence of two claw-like setae on the clasping organs, absence of d2 and dp setae on T2 and T3, absence of alpha and beta setae on Md, shape of hemipenis) from other genera of the tribe. Including the new species, the number of non-marine ostracods known from inland waters of Texas is now 118 species in 45 genera. With the aim of documenting ostracod biodiversity in Texas (USA) by including fossils, we sought documents published from 1927 to 2022 and were able to list 673 ostracod taxa belonging to 142 genera. Among the fossils, 73 ostracods were the oldest records during the Pennsylvanian period (ca. 310 mya), while there were only 42 taxa reported from the Holocene. The Eocene had the highest number of ostracods (126 taxa). In comparison, the living species had only 18 of 673 taxa that were considered nonmarine forms. There are only six species in common with the fossils and recent records. These results suggest the potential for relatively high ostracod species richness and diversity in Texas. This is indeed strongly supported by the present study and the described new genus and its type species (Tuberocandona leonidasi sp. nov.).