Opiona graeningi, Shear, William A., 2011

Shear, William A., 2011, Cave millipeds of the United States. XI. Opiona graeningi, n. sp., a troglomorphic caseyid milliped from Siskiyou County, California, with comments on the genus Opiona Chamberlin 1951 (Diplopoda, Chordeumatida, Caseyidae), Zootaxa 3114, pp. 50-56 : 52-54

Opiona graeningi , n. sp.

Figs. 1–10

Types. Male holotype, one female and two male paratypes from Trail Junction Cave, Marble Mountain Wilderness Area, Klamath National Forest, Siskiyou Co., CALIFORNIA, collected 4 July 2010 by G. O. Graening and David Weaver. Types and other specimens deposited in California Academy of Sciences, San Francisco.

Etymology. This species is named for Gary O. Graening, a speleobiologist who has been active in cave conservation for 14 years, and has bioinventoried over 500 caves in California, Arkansas, and Oklahoma, and in the process, has discovered over 20 new troglobiotic taxa, including several millipeds.

Diagnosis. Distinct from other species of Opiona in the fimbriate margins of the angiocoxite branch sheathing the flagellocoxite, the lack of pigmentation and the poorly developed and pigmented ocelli.

Description. Male (fig. 1) about 12.2 mm long, 1.2 mm wide. Ocelli eight, poorly pigmented, irregular in size and shape (fig. 2). Fully extended, antennae reach posterior margin of fifth body segment. Segments cylindrical, lacking or with obscure lateral striae. Body lacking pigment.

First legpair (fig. 3) robust, six-articled, prefemora to tarsi set ventrally with specialized setae (fig. 4). Second legpair (fig. 5) reduced in size, six-articled, coxae with gonapophyses (fig. 5, ga) about 2/3 length of telopodites (fig. 5, t), trochanters swollen, subglobular, tibiae fused with tarsi, claws vestigial; anterior surfaces of gonapophyses set with long, flexuous setae. Third legpair (fig. 5) seven-articled, with coxae (fig. 5, cx3) greatly extended ventrally, tips of coxal projections with flexuous setae, densely set on anterior surface with short, sharply tapering, decurved setae; telopodites attached near distal extremity, prefemora (fig. 5, pf3) flattened, subglobose in anterior view, more distal podomeres greatly reduced in size. Legpairs four to seven without modifications, of normal size.

Gonopods (figs. 8–10; see discussion above for abbreviations on figures) with flattened, band-like sternum broadly extended laterally, partially fused to flattened coxae. Vestigial telopodite arising laterally, single articled, with scattered setae. Anterior angiocoxites with two branches, lateral short, acute, mesal long, curved laterally; posterior angiocoxites as sheath for flagellocoxite, edges fimbriated. Flagellocoxite arising at base of sheath, divided into four or more thin tubes. Colpocoxites lobe-like, poorly sclerotized, seen as collapsed in figs 9, 10. Ninth legpair (fig. 6) with coxosternites fused, bearing coxites broad in lateral or mesal view, with sinuous edge in anterior or ventral view; telopodites laterally flattened, broadly expanded, obvious in lateral view of whole animal (fig. 1). Tenth coxae enlarged, with broadly excavate glands, long, curved, mesodistal hooks (fig. 7). Following legpairs not modified.

Female as male in nonsexual characters.

Additional localities. CALIFORNIA: Siskiyou Co.: Klamath National Forest, Marble Mountain Wilderness Area, Frozen Falls Cave, 5 September 2010, G. O. & Guy Graening, m, f, juvs.; Bigfoot Cave, 3 September 2010, G. O. & Guy Graening, mm, f; Planetary Dairy Cave, 4 July 2010, G. O. Graening & David Weaver, m; Upstairs Downstairs Cave, 4 September 2010, G. O. & Guy Graening, m ff, juvs.

Samples from the following caves consist of females and/or juveniles that are consistent with known females and juveniles of Opiona graeningi ; all are from the Marble Mountain Wilderness Area: Corkscrew Cave, Skunk Hollow Cave, Echoplex Cave, Apogee Cave, Brokedown Palace Cave. All collections by G. O. and Guy Graening, September, 2010.

Notes. The Marble Mountain Wilderness Area consists of about 980 km 2 centered around the Salmon Mountains, part of the Klamath Mountain geomorphic province. The area has a diverse geology but includes much limestone, supporting numerous caves.

The Klamath Mountains geomorphic province contains several marble lenses of Paleo-Pacific Ocean origin that date to the upper Paleozoic and lower Mesozoic Eras. These units were transported across the Pacific Ocean, metamorphosed, and accreted to the western coast of North America in Late Mesozoic time. The Marble Mountains are the most extensive of these lenses, displaying well-developed karstification and subsequent glaciation in an alpine setting with elevations ranging from 1200 to 2000 m. Although small in extent (circa 400 hectares), the Marble Mountains contain a plethora of subterranean openings in the 120-m thick calcitic and dolomitic marble; over 50 km of cave passage have been mapped over a 48-year period by speleologists, and new caves and passages are found each year ( Knutson et al. 1999). This extensive subterranean network has provided a stable and persistent habitat for exapted fauna to colonize. Furthermore, this karst unit is isolated from similar geologic units, and the larger Klamath Mountains is itself considered an "island" of distinct geologic and geomorphic composition, enabling a unique fauna and flora to develop. In fact, the large number of endemic plant and animal species contained in this region (the Klamath-Siskiyou coniferous forests ecoregion) has distinguished it as one of the biodiversity hotspots of North America ( Stein et al. 2000) and one of the world’s most biologically valuable ecoregions (one of the “Global 200”, Olson and Dinerstein 1998). Opiona graeningi is the first troglobiont to be described from inside the Marble Mountains, but other cave-adapted or cave-limited taxa await description, such as another milliped species ( Conotylidae : Lophomus or gen. nov.), a dipluran ( Campodeidae ), a rockcrawler ( Grylloblattidae : Grylloblatta ), and a flatworm (Tricladida). Other narrow endemics have been found inside the caves of the Marble Mountains, such as the Klamath sideband snail ( Bradybaenidae : Monadenia churchi ) and the Pacific sideband ( M. fidelis leonina ). More faunal discoveries are expected as speleologists endure the dangerous conditions inside these caves, such as technical vertical descents, exposure to winds and subterranean stream immersion in temperatures ranging from 3 to 5° C, unstable ceilings, and abrasive surfaces.

Figures

FIGURES 1 – 3. Opiona graeningi, n. sp. Fig. 1, male, lateral view. Fig. 2, eyes, lateral view. Fig. 3, legpair 1, anterior view.

FIGURES 4 – 7. Opiona graeningi, n. sp. Fig. 4, tarsus of leg 1, anterior view. Fig. 5, legpairs 2 and 3, anterior view, see text for labels. Fig. 6, legpair 9, anterior view. Fig. 7, coxae of legpair 10, anterior view.

FIGURES 8 – 10. Opiona graeningi, n. sp., gonopods. Fig. 8, anterior view. Fig. 9, posterior view. Fig. 10, lateral view. See text for labels.