Opisotretus Attems, 1907

Golovatch, Sergei I., Geoffroy, Jean-Jacques, Stoev, Pavel & Spiegel, Didier Vanden, 2013, Review of the millipede family Opisotretidae (Diplopoda, Polydesmida), with descriptions of new species, ZooKeys 302, pp. 13-77 : 23-27

Genus Opisotretus Attems, 1907

Opisotretus Attems, 1907: 113.

Opisotretus - Attems 1940: 150; Chamberlin 1945: 4; Hoffman 1980: 176, 188; 1982: 722; Simonsen 1990: 53.

Diagnosis.

A genus of Opisotretidae with 19 (♂) or 20 (♀) body segments. ♂ vertex with or without modifications. Metaterga with three regular, transverse rows of bacilliform setae. Frontal margin of midbody paraterga devoid of obvious shoulders. Ozopore usually lying close to very close to caudal margin of paratergite’s caudolateral corner.

Gonopod telopodite elongate, unciform, unipartite; distal part beset with ornamentations (small spines, bacilli or setae) and at least with one evident process, either devoid of or supplied with a short solenomere, but with both an evident accessory seminal chamber and a hairy pulvillus (Figs 8D, 18 B–D, 20C, D, 21, 23C, D, 25, 26F, G).

Type species.

Opisotretus kraepelini Attems 1907, by monotypy.

Remarks.

In addition to the type species, the genus currently contains two described congeners: Opisotretus euthus Chamberlin, 1945 and Opisotretus mimus Chamberlin, 1945. Because the gonopods of Opisotretus euthus are indeed very similar to those of Opisotretus kraepelini as depicted by Chamberlin (1945), the former species is definitely congeneric with the latter one. The identity of Opisotretus mimus , however, remains uncertain, but superficially it strongly reminds of Peronorchus parvicollis Attems, 1907, a species we think belongs in the family Fuhrmannodesmidae . It was originally described from Buitenzorg (= Bogor), Java, Indonesia ( Attems 1907) and seems to be very similar to an opisotretid in showing long bacilliform tergal setae arranged in three transverse rows, notably reduced paraterga, and the ozopores located near the paratergite’s caudal corner. Interestingly, Mauriès and Geoffroy (1999), when redescribing Peronorchus parvicollis from material taken on Mauritius, Indian Ocean, assigned this genus to the family Trichopolydesmidae , as opposed to Hoffman (1980) who had left Peronorchus among the genera of Polydesmidea of uncertain status and family position.

Four new species described below also belong in Opisotretus . A key to all seven Opisotretus species, including Opisotretus mimus , is given below.