Dineutus lethicus Guignot, 1957: 101

Gustafson, Grey T., Hájek, Jiří & Miller, Kelly B., 2016, Description of two new species of Dineutus sensu stricto from Southeast Asia (Coleoptera: Gyrinidae) with a key to the known species of the subgenus, Acta Entomologica Musei Nationalis Pragae 56 (2), pp. 629-643 : 641

Dineutus lethicus Guignot, 1957: 101

This species was described from Réunion Island and placed within Dineutus s. str. by GUIGNOT (1957). By this point in time, however, BRINCK (1955) had presented a diagnosis for members of the subgenus Protodineutus Ochs, 1926 as species with females without the setose furrow on the posterior surface of the ultimate protarsomere and distribution primarily in Africa. Therefore, the African distribution of D. lethicus suggests the species may belong to Protodineutus . The first author was able to examine the holotype and paratypes of D. lethicus (MNHN) and found that not only is it member of Protodineutus , but it is also identical with D. indus ( Fabricius, 1798) . The population from Réunion was described by RÉGIMBART (1882a) as separate subspecies D. indus olivaceus Régimbart, 1882 . Although its status was subsequently doubted by some authors, e.g. PESCHET (1917), we follow the only revisional work of BRINCK (1955) and consider the subspecies as valid. Therefore, Dineutus lethicus Guignot, 1950 syn. nov. is here formally synonymized with D. indus olivaceus Régimbart, 1882 . It appears that Guignot (1950) was unaware of D. indus , a widespread endemic to the Mascarenes, since he only compared his new species to D. proximus Aubé, 1838 , present only on Madasgascar, and none of the species known from the Mascarenes.