Opistocladus Carpenter, 1976

Aristov, D. S., 2020, Revision of the genera Heteroptilon, Nugonioneura and Opistocladus from the Lower Permian of USA (Insecta: Cnemidolestida: Tillyardembiidae, Nugonioneuridae and Parmapteridae), Far Eastern Entomologist 401, pp. 1-9 : 7

Genus Opistocladus Carpenter, 1976

Opistocladus Carpenter, 1976: 342 ; 1992: 126; Rasnisyn, 2002, 112; Béthoux & Nel, 2002:

25; Béthoux et al., 2003: 277; Rasnisyn & Aristov, 2013: 686; 2015: 19.

Type species: Opistocladus arquatus Carpenter, 1976, by original designation.

DIAGNOSIS. Forewing with prominent ScA, reaching wing basal third, precostal field narrow. ScP ends at R. Costal field at base of RS equal in width to subcostal one. RS with few branches, starts at wings mid length, its base lies close to apex of ScP. M with prominent М 5, divided into branches at wings mid length,

MA and RS with fissures, where they are connected by transverse vein. М 5 goes into CuA after its first divide into branches. Posterior branch of CuA with fissures where transverse veins merges with it. Anal area modified into clavus.

COMPARISON. Opistocladus is most similar to genus Parmaptera Aristov et

Rasnitsyn, 2015 from Lower Permian locality Chekarda in Russia (Kungurian Stage,

Perm Region) but differs in narrow costal field, fewer number of RS branches and

М 5, merges into CuA after its first branching. In Parmaptera costal field at base of

RS four times wider than subcostal one, RS subpectinate, with five or more branches, М 5 merges into CuA after its second branching. CuP curved at its base.

Anal area not modified into clavus (Aristov & Rasnitsyn, 2015). Lacking of precostal field on holotype of P. permiana is a result of preservation; perpendicular anterior branches at the SC base usually merge with SC and ScA .

SPECIES INCLUDED. Type species only.

NOTE. The taxonomic position of Opistocladus strictus Carpenter, 1976 from

Elmo (Carpenter, 1976) and O. kargalensis Rasnitsyn et Aristov, 2013 from Kargala locality ( Russia: Orenburg Region, Middle Permian, Urzhumian Stage (Carpenter,

1976; Rasnitsyn & Aristov, 2013) are not certain because of these taxa considerably differs from O. arquatus and probably belong to the family Tococladidae .