Opiona catorycha Shear & Crawford, 2019

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 : 575-578

Opiona catorycha Shear & Crawford , new species

Figs. 6–14

Material examined: Type specimens. Male holotype ( UWBM) from Oregon Cave, Oregon Caves National Monument , Josephine Co., Oregon (42.0974º N, -123.4099º W), collected 31 August 1992 by a drift net intercepting the inflow of the main cave stream “River Styx” where it flows from an impenetrable opening into a passage along the cave’s tour route . Male and female paratypes from No Name Cave , 17.8 km south-southwest of Grants Pass , Josephine Co., Oregon (42.2880 º N, -123.2519 º W), collected 11 November 2018, by Neil Marchington and 8 August 2011, by Darrell Ubick ( Ubick specimens deposited in the California Academy of Sciences , CASC).

Diagnosis. Opiona catorycha can be confused with no other Opiona species, due to the extraordinary complexity of the anterior gonopods, featuring numerous flagelliform branches of at least five distinct types combined with its troglomorphic adaptations ( Figs. 11, 12 ).

Description. Male holotype. Length about 13 mm, width 1.0 mm. Eyes absent ( Fig. 7 ). Rings cylindrical. Metazonital setae short, slightly clavate. Fourth ring enlarged, trunk flexed at fourth ring ( Fig. 6 ). Unpigmented (both preserved and when alive). First legpair incrassate, podomeres with distinctive ensiform setae ventrally, coxae with large posterior lobes bearing five or six peg-like setae ( Fig. 8 ). Second legpair reduced to six podomeres, coxal gonapophyses about as long as prefemora, with fine, tightly appressed setae; distal three podomeres with curled setae ( Fig. 9 ). Third legpair with coxae greatly extended ventrally into subclavate lobes with apical tufts of setae, prefemora greatly shortened, flattened, ventrolaterally expanded; femora, postfemora, tibiae and tarsi much reduced, and tarsus without claw ( Figs. 9, 10 ). Anterior gonopods ( Figs. 11–12 ) extraordinarily complex, sternum (s, Figs. 11, 12 ) well sclerotized anteriorly and posteriorly, with sigmoidially curved, fimbriate lateral processes. Anterior angiocoxite (aac, Figs. 11, 12 ) in anterior view with two relatively broader branches: the lateralmost shorter, acute; the more medial longer, broader, with subapical tooth—medial to these is a series of curved, flattened, blade-like pseudoflagella (pf, Figs. 11, 12 ), and more medial still a few fine, fimbriate pseudoflagella. In posterior view, additional pseudoflagella are seen, these with knobbed tips, knobs set with fine filaments ( Fig. 12 ). Near lateral base of angiocoxite on each side, a single thin filament (f, Fig. 12 ) with fine branches. Posterior angiocoxite (pac, Fig. 12 ) with posteriorly curved, fimbriate branch, more anterior, erect, flattened branch; at least 3 strong pseudoflagella with blunt, slightly bifurcate tips arise behind posterior colpocoxite. Colpocoxites (cc, Fig. 12 ) lobe-like, poorly sclerotized. Ninth legpair with three-branched coxal processes, branches curved, acute. Telopodite article typically swollen, flattened, cordate in lateral view ( Fig. 13 ). Tenth legpair typical of genus, coxae with large, deep glands, posterior hooked process ( Fig 14 .).

Female paratype. Length about 13.2 mm, width 1.0 mm. Similar to male in nonsexual characters. First and second legpairs reduced. Third legpair with sternum strongly modified, cupped anteriorly, partially enclosing vulvae.

Distribution. Known only from the type and paratype localities, but possibly occurring in other marble caves in the region. Numerous small lenses of marble are scattered through the area between Oregon Cave and No Name Cave, many of them with small caves (N. Marchington, pers. com. to WAS).

Notes. The differences between the scanning electron micrograph of the gonopods ( Fig. 11 ) and the drawing ( Fig. 12 ) are instructive. The drawing of the anterior gonopods was made from material temporarily mounted in glycerine on a microscope slide and the gonopods were flattened from their normal position by the cover glass, expanding and pushing apart the tightly clustered pseudoflagella, thereby allowing the several types to be distinguished. The pressure of the cover glass also changed the orientation of a number of features of the gonopods. Shear (2011) discussed in detail the gonopod structure of species of Opiona , recognizing two groups, but found the gonopods of O. graeningi to be somewhat intermediate. The gonopods of O. catorycha have a shape similar to that of O. graeningi , the main differences being the deeply divided anterior angiocoxites of the former, and the very numerous pseudoflagella. The coxal process of the posterior gonopods of O. graeningi is flattened and blade-like, while that of O. catorycha is three-branched.

Figure 6 depicts a freshly preserved specimen from No Name Cave. As in other species of Opiona , the fourth ring is enlarged to accommodate powerful muscles attached to the third legpair and the trunk flexes at almost a right angle at this point. It seems safe to assume that the male third legpair is involved somehow in mating, but there have been no observations of mating in any caseyid.

Although the holotype was intercepted in stream flow, we assume that the species is terrestrial and that the specimen was washed downstream from a cave passage not accessible to humans. No specimens of this species (or any caseyid) were taken at other times in the year-long baited pitfall trapping throughout Oregon Cave. No Name Cave is also a paratype locality for the unique relict spider Trogloraptor marchingtoni Griswold, Audisio & Ledford, 2012 , which is the only described species of the family Trogloraptoridae Griswold, Audisio & Leford, 2012 .

Etymology, The species epithet (Latinized Greek) is an adjective meaning “underground, in caves.”

Figures

FIGURE 6. Opiona catorycha, new species. Freshly preserved male from No Name Cave, lateral view; g, gonopod; L1–L3, legs 1–3, respectively; R4, ring 4; t9, telopodite of leg 9; tL3, telopodite of leg 3 (small object just to right of label).

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.

FIGURES 11, 12. Opiona catorycha, new species. Fig. 11. Gonopods, posterior view (scanning electron micrograph); aac, anterior angiocoxite; cc, colpocoxite; pac, posterior angiocoxite; s, gonopod sternum. Fig. 12 Drawing of same; labels as in Fig. 11, pf, pseudoflagellar branches..

FIGURES 13, 14. Opiona catorycha, new species. Fig. 13. Left leg 9, anterior view. Fig. 14. Legpair 10, anterior view.