Circulocryptus, Golovatch, Sergei I., 2016

Golovatch, Sergei I., 2016, The millipede family Cryptodesmidae in Indochina (Diplopoda, Polydesmida), ZooKeys 578, pp. 33-43 : 36-37

Taxon classification Animalia Polydesmida Cryptodesmidae

Circulocryptus gen. n.

Diagnosis.

Cryptodesmidae with gonopod telopodite stout, subcircular, clearly twisted (= seminal groove mostly running on lateral face) and vaguely bipartite, supplied with a mesal prefemoral process at base; a considerable, spiniform, retrorse solenomere terminating a sigmoid seminal groove and placed near telopodite midway; neither an accessory seminal chamber nor a hairy pulvillus.

Name.

To emphasize the subcircular gonopods; gender masculine.

Description.

Small-sized Cryptodesmidae (adults about 1 cm long and 3 mm wide) with 20 segments (trunk composed of collum plus 17 podous and one apodous rings, plus telson); a flabellate collum covering the head from above. Antennae clearly clavate. Paraterga short and very broad, slightly declined, mostly squarish laterally, lobulate and/or radiate anteriorly, laterally and posteriorly; ozopores invisible, pore formula untraceable. Middle parts of metaterga with seriate transverse rows of abundant setigerous knobs/tubercles partly extending onto paraterga; tergal setae present, simple; neither sternal cones nor leg modifications. Gonopod aperture subcordiform; gonopod telopodites in situ held parallel to each other, each vaguely bipartite and complex, with a mesal, parabasal, prefemoral process; basal part of telopodite clearly twisted and surmounted by a long, spiniform solenomere terminating a sigmoid seminal groove and situated at about telopodite midway. Neither an accessory seminal chamber nor a hairy pulvillus.

Type-species.

Circulocryptus faillei sp. n.

Remarks.

Globally, the Cryptodesmidae is a relatively small family that encompasses almost 40 genera and nearly 130 species and ranges from Mexico to Argentina in the Americas, occurring also in tropical Africa and tropical to subtropical Asia to Papua New Guinea and Japan in the East ( Minelli 2015). Only three genera have hitherto been known in the entire family, in which the gonopod shows a distinct prefemoral process arising mesally near the origin of the seminal groove: Astrolabius Verhoeff, 1931, with 2 species from Papua New Guinea ( Golovatch et al. 2010), Dyakryptus Hoffman, 1961, monobasic, from Eastern Malaysia, Sabah, Borneo ( Hoffman 1961, 1980), and Sarissocryptus Hoffman, 1993, monobasic, from Eastern Malaysia, Sarawak, Borneo ( Hoffman 1993). This process can be completely mesal ( Astrolabius ) or be twisted laterad ( Dyakryptus and Sarissocryptus ). Based of the above synapomorphy in gonopod structure, i.e. the presence of a basal prefemoral process, coupled with a coherent distribution pattern in Borneo and New Guinea, these three genera form the tribe Dyakryptini Hoffman, 1973 ( Golovatch 2015). Circulocryptus gen. n. definitely joins this trio, but differs in the gonopods being especially elaborate and subcircular (versus far from so elaborate and not too strongly curved), the telopodites distinctly twisted basally (versus not twisted), and the solenomere lying much more basally, close to telopodite midlength (versus subapical). The range of Dyakryptini is thus considerably extended into continental SE Asia.