Opiona Chamberlin, 1951

Shear, William A. & Crawford, Rodney L., 2019, Cave millipedes of the United States. XVI. Two new species from Oregon Caves National Monument, Oregon (Chordeumatida, Conotylidae and Caseyidae), Zootaxa 4674 (5), pp. 571-580 : 575

Genus Opiona Chamberlin, 1951

Type species: Opiona columbiana Chamberlin, 1951 .

The most recent revision is Gardner & Shelley (1989); Shear (2011) adds one more species.

Opiona presently includes 14 species and is distributed from central California to the Alexander Archipelago, Alaska ( Gardner & Shelley 1989, Shelley et al. 2007). The single previously described troglomorphic species is Opiona graeningi from caves in the Marble Mountains, Siskiyou Co., California (Shear 2011). Numerous additional surface-dwelling species of Opiona await description and naming.

Opiona is best distinguished from other sympatric caseyid genera by the characteristic modification of the third leg, in which the telopodite arises distal to the midpoint of the elongated coxa and has a strongly inflated prefemur ( Figs. 9, 10 ).

Figures

FIGURES 7–10. Opiona catorycha, new species. Fig. 7. Head and collum, frontal view. Fig. 8. Legpair 1, anterior view. Fig. 9. Legpairs 2 and 3, anterior view; cx3, coxa of leg 3; pf3, prefemur of leg 3; S3, sternum of legpair 3; sp2, spermatic process of coxa 2; t2, telopodite of leg 2; t3, telopodite of leg 3. Fig. 10. Tips of legpair 3 coxae, anterior view.