Copytus posterosulcus Wang, 1985

Coimbra, João Carlos, Bergue, Cristianini Trescastro & Ramos, Maria Inês Feijó, 2020, Is Copytus Skogsberg, 1939 (Crustacea: Ostracoda) a neocytherideid? With description of a new family and two new species, Zootaxa 4729 (2), pp. 177-194 : 184

Copytus posterosulcus Wang (in: Zhao, Wang & Zhang 1985).

This is a species with a distinct anterior (not posterior as originally described) horizontal sulcus. Wang describes it as being adont with a very wide inner lamella and deep, wedge-shaped vestibulum with few short, straight radial pore canals anteriorly; a shallower crescentic vestibulum occurs posteriorly. The adductors are described as a vertical row of four imprints, but no mention is made of an antennal scar and it is not possible from the illustrations (pl. 21) to be certain of the scars. This is a very small species (l = 0.52–0.55 mm). Jellinek (1993, taf. 8: 184–185), illustrated C. cf. posterosulcus with four adductor muscle scars in a vertical row. Wang’s species was briefly described and illustrated by Titterton & Whatley (2006) based on few valves recorded in the Solomon Islands; unfortunately, nothing was said about the central muscle scars or another internal feature. It is noteworthy that an SEM image ( Titterton & Whatley 2006, pl. 1: 5) shows a rounded group of four adductor muscle scars. Surprisingly, the drawings in figure 4: 1–2, 4–5 show that the authors mixed two different species, and only the illustrations in figure 4: 4–5 are similar to C. posterosulcus , but show the adductor muscle imprints in a vertical row as is typical of Neocytherideis . However, in the PhD thesis of Titterton (1984, pl. 33), she described the central muscle scars of C. posterosulcus as “an ovate patch of 4 adductor scars, dorsal scar ovate, ventral 3 scars wedge-shaped; ovate frontal scar distant to adductor scars”. Zhao & Wang (1988, pl. 1, fig. 24) illustrated a RV (not LV as indicated) of C. posterosulcus , and concluded that this species is part of a group of endemic ostracods living in the East China Sea and the northern part of the South China. Tanaka et al. (2009, pl. 1, fig. 2) illustrated a LV (not RV as originally stated) of C. posterosulcus recovered from the Northeastern Gulf of Tonking, Vietnam.