With 53 formally described species, the genus Cypretta is one of the most common freshwater ostracod genera in the world. It has a mainly circumtropical distribution. The type species, Cypretta tenuicauda (Vávra, 1895), was described from Zanzibar (Africa) in a superficial way. Therefore, the morphology and identity of this species and of the genus remained problematic until today. Here, we redescribe Cypretta tenuicauda from the original type material and discuss the morphology of the species and the diagnosis of the genus. The species is characterized by the presence of anterior marginal septa in both valves, the sub-triangular carapace shape in lateral view, the right valve overlapping the left valve, the generally wide carapace and the presence of a serrated posteroventral inner list in the right valve. In addition, both α and β setae on the mandibular palp are long and thin, claws Ga and Gp on the caudal ramus are elongated and seta-like, while the caudal ramus itself is equally slender. The caudal ramus attachment is reduced to a simple branch. The present redescription of the type species will assist in creating order in what is now a taxonomically confused genus.
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RBINS Staff Publications 2023
Two species have been attributed to the genus Teretoctopus Robson, 1929: T. indicus Robson, 1929, the type species of the genus, and T. alcocki Robson, 1932. Of the four original T. alcocki syntypes, we relocate and redescribe the remains of two of them, and designate one of them the lectotype. Of three original T.indicus syntypes, it is probable that one is lost permanently, but the whereabouts of two of them remains unknown. What we can discern from remaining T. alcocki type material, augmented with descriptions of these specimens by Anne Massy and Guy Robson, is compared with what is known of the type species of this genus, T. indicus. A rediagnosis of the genus Teretoctopus is proffered, and relationships between this genus and others historically referred to as “inkless octopuses” are evaluated. While Teretoctopus has nomenclatural priority over Vulcanoctopus González et Guerra, 1998 and Muusoctopus Gleadall, 2004, for which it is possibly the senior synonym, and shares many characters and states with Ameloctopus Norman, 1992, further taxonomic resolution of relationships among these genera must await description and molecular analyses of accurately identified Teretoctopus specimens from the Gulf of Oman and northern Arabian Sea.
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RBINS Staff Publications 2026 OA
