taxonID	type	description	language	source
03C78796D845A119FF1AF8EFFB53FB08.taxon	type_taxon	Type species Paropiona gardneri Shear & Marek, new species.	en	Shear, William A., Marek, Paul E. (2025): Additions to the millipede family Caseyidae Verhoeff, 1909. IV. Two new genera and three new species (Chordeumatida, Striarioidea, Caseyidae). Zootaxa 5631 (3): 533-547, DOI: 10.11646/zootaxa.5631.3.7, URL: https://doi.org/10.11646/zootaxa.5631.3.7
03C78796D845A119FF1AF8EFFB53FB08.taxon	diagnosis	Diagnosis. Species of this genus are unique among caseyids in entirely lacking gonopod colpocoxites. Differing from Vasingtona Chamberlin, 1941 and Ochrogramma Gardner & Shelley, 1989 in lacking the ventral lamina of the mandible in males seen in those genera. From Caseya Cook & Collins, 1895, the new genus differs in not having the coxae of the seventh legpair of the male greatly enlarged and with complex processes. In species of Opiona Chamberlin, 1951, the gonopods have colpocoxites and flagellocoxites; these are absent in species of Paropiona gen. nov. In addition, the reduced telopodites of the male ninth legs of Opiona species are rounded and button-like, while in species of Paropiona they are narrow and sinuously curved. From Opionoides gen. nov., Paropiona species differ in lacking gonopod flagellocoxites (possibly vestigial in one species); Opionoides gonopods have both flagellocoxites and colpocoxites and have a crown of thorny processes on the anterior angiocoxites. The posterior angiocoxites are densely fimbriate on their mesal surfaces in Opionoides; these features are not found in Paropiona species. The ninth leg telopodites of Opionoides cataracta, sp. nov., are like those of Opiona species.	en	Shear, William A., Marek, Paul E. (2025): Additions to the millipede family Caseyidae Verhoeff, 1909. IV. Two new genera and three new species (Chordeumatida, Striarioidea, Caseyidae). Zootaxa 5631 (3): 533-547, DOI: 10.11646/zootaxa.5631.3.7, URL: https://doi.org/10.11646/zootaxa.5631.3.7
03C78796D845A119FF1AF8EFFB53FB08.taxon	etymology	Etymology. The name of the new genus is feminine in gender and conveys its relationship to the genus Opiona.	en	Shear, William A., Marek, Paul E. (2025): Additions to the millipede family Caseyidae Verhoeff, 1909. IV. Two new genera and three new species (Chordeumatida, Striarioidea, Caseyidae). Zootaxa 5631 (3): 533-547, DOI: 10.11646/zootaxa.5631.3.7, URL: https://doi.org/10.11646/zootaxa.5631.3.7
03C78796D845A119FF1AF8EFFB53FB08.taxon	description	Description. Caseyid millipedes with 30 rings, about 8 – 12 mm long (Figs 30, 31) Mandibles of males not modified. Male first legpair (Fig. 1) somewhat reduced, with few elongate, flattened, spiral setae on postfemur and tibia; tarsi with sparse ventral tarsal comb. Male second legpair (Figs 2, 13) with long coxal gonapophyses slightly curved, subequal in length to reduced telopodites; telopodite femora long, more distal podomeres much shortened. Gonapophyses with opening of vas deferens at base, more distal accessory pore present. Male third legpair (Figs 3, 13) with prominent, flattened, rounded coxal lobes tightly appressed in midline, lacking apical tuft of modified setae. Telopodites attached midway distal on coxae, with four podomeres; prefemora not flattened or enlarged. Male legpairs four to seven slightly encrassate, otherwise unmodified. Gonopods (Figs 4 – 7, 14 – 16) with coxae and sternum fused without midline suture. Anterior angiocoxites slightly inclined posteriorly, simple, erect or sinuously curved. Posterior angiocoxites present or absent. Flagellocoxite absent or possibly vestigial in P. gardneri sp. nov. Gonopod telopodites large, robust, erect and divergent or passing anteriorly between angiocoxites. Colpocoxites absent. Male legpair nine (Figs 8 – 10, 17 – 20) with elongate coxae bearing divided coxal process, the mesal branch thin and appressed to telopodite. Coxal pore present at base of coxal process. Telopodite single podomere, narrow, elongate, with apical tuft of stout setae directed mesally. Male legpair 10 (Figs 11, 12, 21) with enlarged coxae bearing large, frequently everted glands and hooked coxal process; trochanters with small, distal, bifid process; prefemora and femora with a ventral row of acute denticles.	en	Shear, William A., Marek, Paul E. (2025): Additions to the millipede family Caseyidae Verhoeff, 1909. IV. Two new genera and three new species (Chordeumatida, Striarioidea, Caseyidae). Zootaxa 5631 (3): 533-547, DOI: 10.11646/zootaxa.5631.3.7, URL: https://doi.org/10.11646/zootaxa.5631.3.7
03C78796D845A119FF1AF8EFFB53FB08.taxon	discussion	Notes. The modifications of the pregonopodal legs of the males in the two species of Paropiona are very similar to those found in species of Opiona. However, we noted a feature of the gonapophyses of the second legs that has not been seen before in any caseyids: an accessory pore distal to the opening of the vas deferens, which is situated at the base of the gonapophysis. An examination of a few species of Opiona confirms that at least in those species, this pore also occurs. This accessory pore is not present in species of the subfamily Ochrogrammatinae (Shear & Marek 2024) nor in species of Caseya. The gonopods of the two species of Paropiona differ strongly from those of Opiona species in lacking colpocoxites, arising from a coxosternum and lacking flagellocoxites (a single vestigial flagellocoxite may be present in P. gardneri sp. nov.), which are numerous in those species, and often complexly sheathed by the posterior angiocoxites. Paropiona gonopods are in fact so different from those of any other caseyids that establishing even tentative homologies among them is difficult. The gonopods proper arise from a coxosternite and consist of two divisions: anterior and posterior. The anterior division is angiocoxal and in Paropiona gardneri sp. nov., consist of anterior and posterior angiocoxites, while in Paropiona aenigma sp. nov., there is only a single angiocoxite. While functional flagellocoxites appear to be absent in both species of the genus, a small vestigial branch arising from the posterior surface of the anterior angiocoxite in P. gardneri gonopods may be flagellocoxal. In P. aenigma sp. nov., the posterior angiocoxites and any trace of flagellocoxites are apparently absent. We are referring to the posterior divisions of the gonopods as telopodites because they appear to arise from sockets in the coxosterna. It is possible that these structures could also be heavily sclerotized homologs of what we have called the colpocoxites in other caseyids. However, caseyid colpocoxites are very lightly sclerotized and amorphous in shape. If our interpretation is correct, colpocoxites are absent in species of Paropiona. Telopodites are uncommon as a component of the gonopods of most of the families of Chordeumatida, the functional gonopod divisions developing primarily from the coxae. The ninth legs of the males of Paropiona species are reduced to the coxae and single telopodite podomeres, as is typical of caseyids; however, instead of being rounded, globular and button-like, they are elongate and curved, with tufts of stout, ensiform setae in a mesal group at their tips. The coxal processes are bifid, as in many Opiona species, but the lateral branch is small, thin, and usually closely appressed to the telopodite so that its presence is sometimes obvious only in SEM images. The mesal branch is much more robust, sinuously curved and as long or slightly longer than the telopodite. At the base of this mesal branch is a small pore; we have also observed such a pore in species of Ochrogramma (Shear & Marek 2024) and think this pore is homologous to the much larger pores of the tenth coxae, where spermatophores are formed. While the majority of collections of both species of Paropiona gen. nov., were collected from November to March, as expected for winter-active chordeumatidan millipedes, some were taken as early as September and as late as June, indicating perhaps a longer period of activity than in other chordeumatidans in the region.	en	Shear, William A., Marek, Paul E. (2025): Additions to the millipede family Caseyidae Verhoeff, 1909. IV. Two new genera and three new species (Chordeumatida, Striarioidea, Caseyidae). Zootaxa 5631 (3): 533-547, DOI: 10.11646/zootaxa.5631.3.7, URL: https://doi.org/10.11646/zootaxa.5631.3.7
03C78796D847A11CFF1AFD37FE72FE18.taxon	description	Figs 1 – 12	en	Shear, William A., Marek, Paul E. (2025): Additions to the millipede family Caseyidae Verhoeff, 1909. IV. Two new genera and three new species (Chordeumatida, Striarioidea, Caseyidae). Zootaxa 5631 (3): 533-547, DOI: 10.11646/zootaxa.5631.3.7, URL: https://doi.org/10.11646/zootaxa.5631.3.7
03C78796D847A11CFF1AFD37FE72FE18.taxon	materials_examined	Types: Male holotype from east of Frontage Road on Rose Valley Road, Cowlitz Co. Washington, 46.1692 ° N, - 122.7080 ° W, collected 29 April 2007 by W. Leonard and C. Richart (collection number CR 1840). Two male and four female paratypes from Ellsworth Creek Preserve, 46.431 ° N, - 123.890 ° W, collected 23 November 2003 by W. Leonard et al. Parts of the paratype males are mounted on SEM stubs WS 37 - 18 and WS 38 - 6.	en	Shear, William A., Marek, Paul E. (2025): Additions to the millipede family Caseyidae Verhoeff, 1909. IV. Two new genera and three new species (Chordeumatida, Striarioidea, Caseyidae). Zootaxa 5631 (3): 533-547, DOI: 10.11646/zootaxa.5631.3.7, URL: https://doi.org/10.11646/zootaxa.5631.3.7
03C78796D847A11CFF1AFD37FE72FE18.taxon	etymology	Etymology. We are pleased to name this unusual species for Michael R. Gardner, coauthor of the first comprehensive review of the family Caseyidae (Gardner & Shelley 1989).	en	Shear, William A., Marek, Paul E. (2025): Additions to the millipede family Caseyidae Verhoeff, 1909. IV. Two new genera and three new species (Chordeumatida, Striarioidea, Caseyidae). Zootaxa 5631 (3): 533-547, DOI: 10.11646/zootaxa.5631.3.7, URL: https://doi.org/10.11646/zootaxa.5631.3.7
03C78796D847A11CFF1AFD37FE72FE18.taxon	diagnosis	Diagnosis. Distinct from Paropiona aenigma sp. nov., the only other known species in the genus, in having both anterior and posterior angiocoxites of the gonopods. Only a single angiocoxite is present in P. aenigma.	en	Shear, William A., Marek, Paul E. (2025): Additions to the millipede family Caseyidae Verhoeff, 1909. IV. Two new genera and three new species (Chordeumatida, Striarioidea, Caseyidae). Zootaxa 5631 (3): 533-547, DOI: 10.11646/zootaxa.5631.3.7, URL: https://doi.org/10.11646/zootaxa.5631.3.7
03C78796D847A11CFF1AFD37FE72FE18.taxon	description	Description. Holotype male. 11.0 mm long, about 1.1 mm in diameter (Fig. 30). Triangular eyepatch of 21 ommatidia. Thoracic rings smooth, cylindrical, pale brownish gray irregularly marked with cream white. Ring macrosetae short, acute, in nearly straight row across posterior margin of metazonite. First legpair (Fig. 1) short, stout, coxae fused in midline; postfemur, tibia with few elongate, slightly flattened setae. Second legpair (Fig. 2) with coxae bearing long, curved gonapophyses (ga) sparsely setose on anterior surface; vas deferens (vd) and accessory pore (ap) both basal; telopodites (t 2) reduced, femora long, postfemora and tibiae very short, tarsi button-like, clawless. Third legpair (Fig. 3) with elongate coxae (cx 3) extended into broad, flattened, sparsely setose lobes (cl); reduced telopodites (t 3) of four podomeres attached at base of coxal lobes, femora not flattened or enlarged, tarsi with single, long, apical setae. Fourth through seventh legpairs scarcely enlarged. Gonopods (Figs 5 – 7) arising from and fused to coxosternum. Anterior angiocoxites (aac) broad, sigmoid, curved first posteriorly, then anteriorly; posterior angiocoxites (pac) extending anteriorly between anterior angiocoxites, with broad lateral lamella, curved, acute tip. Telopodites (t) large, robust, following curve of posterior angiocoxites, distally divided into many fine microfibers (Fig. 6). Possible vestigial flagellocoxite (f?, Fig. 7) attached to posterior surface of anterior angiocoxite. Ninth legpair (Figs 8 – 10) coxae (cx 9) elongate, with bifid coxal process; medial branch of process (mcp) shorter than telopodite, strongly hooked, with lateral groove or channel running to tip from pore at base of process; lateral branch (lcp) thin, flattened, appressed to mesal surface of telopodite, divided at tip into fine fibers. Telopodite (t 9) narrow, elongate, with apicomedial cluster of many stout setae (Fig. 9). Tenth legpair (Fig, 11, 12) with much enlarged glandular coxae (cx 10) carrying long, posterior, curved process. Telopodite smaller than those of adjacent legs, trochanter (tr 10) with small, bifid process (trp), prefemora (pf 10) and femora (f 10) with rows of short, acute tubercles. Paratype female. 11 mm long, 1.2 mm in diameter. Nonsexual characters as in male. Vulvae not modified, sparsely setose.	en	Shear, William A., Marek, Paul E. (2025): Additions to the millipede family Caseyidae Verhoeff, 1909. IV. Two new genera and three new species (Chordeumatida, Striarioidea, Caseyidae). Zootaxa 5631 (3): 533-547, DOI: 10.11646/zootaxa.5631.3.7, URL: https://doi.org/10.11646/zootaxa.5631.3.7
03C78796D847A11CFF1AFD37FE72FE18.taxon	materials_examined	Records. In addition to the holotype and paratype localities: WASHINGTON: Pacific Co.: Ellsworth Creek Preserve, 14 March 2003, W. Leonard, m, f; Same, 1 mile north on Parapala Road, 46.415 ° N, - 123.892 ° W, 20 June 2003, W. Leonard, m; North Nemah River, 46.492 ° N, - 123.824 ° W, 20 September 2008, C. Richart (collection number CHR 3192), mm; 5.9 mi south of Rt. 6 on Trap Creek, 46.541 ° N, - 123.660 ° W, 334 ’ asl, 19 November 2005, W. Leonard, C. Richart, m.	en	Shear, William A., Marek, Paul E. (2025): Additions to the millipede family Caseyidae Verhoeff, 1909. IV. Two new genera and three new species (Chordeumatida, Striarioidea, Caseyidae). Zootaxa 5631 (3): 533-547, DOI: 10.11646/zootaxa.5631.3.7, URL: https://doi.org/10.11646/zootaxa.5631.3.7
03C78796D842A113FF1AF8C9FB00FFB4.taxon	description	Figs 13 – 21, 31 Types. Male holotype, two male and two female paratypes from Tolmie State Park, 61 st Avenue NE, Olympia, Thurston Co., Washington, 47.120 ° N, - 122.776 ° W, 20 ’ asl, collected 4 February 2003 by W. Leonard. Parts of paratype males are mounted on SEM stub WS 38 - 7.	en	Shear, William A., Marek, Paul E. (2025): Additions to the millipede family Caseyidae Verhoeff, 1909. IV. Two new genera and three new species (Chordeumatida, Striarioidea, Caseyidae). Zootaxa 5631 (3): 533-547, DOI: 10.11646/zootaxa.5631.3.7, URL: https://doi.org/10.11646/zootaxa.5631.3.7
03C78796D842A113FF1AF8C9FB00FFB4.taxon	etymology	Etymology. The species name, a Latin noun in apposition, refers to our original indecision concerning the placement of this species in Opiona or a new genus.	en	Shear, William A., Marek, Paul E. (2025): Additions to the millipede family Caseyidae Verhoeff, 1909. IV. Two new genera and three new species (Chordeumatida, Striarioidea, Caseyidae). Zootaxa 5631 (3): 533-547, DOI: 10.11646/zootaxa.5631.3.7, URL: https://doi.org/10.11646/zootaxa.5631.3.7
03C78796D842A113FF1AF8C9FB00FFB4.taxon	diagnosis	Diagnosis. Distinct from P. gardneri sp. nov. in the undivided angiocoxite of the gonopods (divided in gardneri), relatively shorter telopodites of legpair 2 and in having the coxal processes of legpair 9 spirally curved rather than hooked.	en	Shear, William A., Marek, Paul E. (2025): Additions to the millipede family Caseyidae Verhoeff, 1909. IV. Two new genera and three new species (Chordeumatida, Striarioidea, Caseyidae). Zootaxa 5631 (3): 533-547, DOI: 10.11646/zootaxa.5631.3.7, URL: https://doi.org/10.11646/zootaxa.5631.3.7
03C78796D842A113FF1AF8C9FB00FFB4.taxon	description	Description. Holotype male. 8.0 mm long, 0.75 mm wide (Fig. 31). Other nonsexual characters as described for P. gardneri. First legpair short, stout, arising from fused coxosternum, lacking specialized setae, tarsal comb obscure. Second legpair (Fig. 13) with gonapophyses (ga) short, diverging, bearing long setae on anterior surface; vas deferens and accessory pore not observed; telopodite (t 2) with five podomeres, terminal podomere button-like, clawless. Third legpair (Fig. 13) with short, convergent coxal lobes (cl) sparsely setose, single long terminal seta; telopodites (t 3) with four podomeres, terminal podomere with long, single seta. Gonopods in anterior view (Fig. 14) bilaterally fused as coxosternum (cxs, Fig. 16), undivided angiocoxites (ac) simple, semiquadrate. In posterior view (Fig. 15) angiocoxites (ac) slightly spatulate. Telopodites (t) as large as angiocoxites, emerging from distinct sockets in coxae, laterally flattened, diverging, with long terminal process tipped with minute spicules. In oblique lateral view (Fig. 16), angiocoxites (ac) cupped inward, telopodites (t) basally broad. Ninth legpair (Figs 17 – 20) sternum (s 9) narrow, elongated coxae (cx 9) widely separated; coxal processes (cp) with mesal branch thin, short, acute, lateral branch robust, spirally curved, with pore (p) at base; telopodites (t) slightly longer than coxal processes, narrow, with small tuft of stout setae at tip (Fig. 20). Tenth legpair (Fig. 21) sternum (s 10) broad, coxae (cx 10) globular, enlarged, with large pores (p), short, curved, blunt coxal processes (cp); prefemora and femora with rows of acute tubercles. Paratype female. 8.0 mm long, 0.8 mm in diameter. Nonsexual characters as in male. Vulvae not modified, sparsely setose.	en	Shear, William A., Marek, Paul E. (2025): Additions to the millipede family Caseyidae Verhoeff, 1909. IV. Two new genera and three new species (Chordeumatida, Striarioidea, Caseyidae). Zootaxa 5631 (3): 533-547, DOI: 10.11646/zootaxa.5631.3.7, URL: https://doi.org/10.11646/zootaxa.5631.3.7
03C78796D842A113FF1AF8C9FB00FFB4.taxon	description	Records. In addition to the holotype and paratype locality: WASHINGTON: Clallam Co.: Deer Park Road, 6.1 mi north of US 101, 1123 ’ asl, 14 June 2003, W. Leonard, m. Grays Harbor Co.: Canyon River, 47.304 ° N, - 123.509 ° W, 514 ’ asl, 3 October 2003, W. Leonard, m, ff; Canyon River, 6 mi west, 1.5 mi north of Matlock, 47.436 ° N, - 123.874 ° W, 26 May 2003, W. Leonard, mm; 47.314 ° N, - 123.540 ° W, 13 October 2003, W. Leonard, m, f.; Canyon River, 47.303 ° N, - 123.509 ° W, 22 June 2002, W. Leonard, m, f. Jefferson Co.: Queets River Road, 0.8 mi from US 101, Olympic National Park, 3 June 2003, W. Leonard, mf; same, but 4.8 mi from US 101, mm; Nolan Crook at US 101, 47.701 ° N, - 124.320 ° W, 3 March 2002, W. Leonard, m, ff; Willoughby Creek at Hoh River, 3.5 mi east of US 101, 28 March 2003, W. Leonard, mm; Satsop River, Grady Road, 2 mi north of US 101, 22 June 2001, W. Leonard, m, f. Lewis Co.: seep beside road along Cowlitz River, east of Riffle Lake, 46.462 ° N, - 122.163 ° W, 650 ’ asl, 9 April 2004, C. Richart, W. Leonard, m; Road # 4000, southwest of Pe El MacDonald Road, 46.524 ° N, - 123.194 ° W, 650 ’ asl, 3 January 2005, W. Leonard, mm, ff. Mason Co.: Potlatch State Park, Shelton, 47.361 ° N, - 123.157 ° W, 20 ’ asl, 17 February 2002, W. Leonard, m; Skokomish Valley Road at US 101, Purdy Canyon near George Adams Salmon Hatchery, 47.301 ° N, 123.182 ° W, 15 February 2003, W. Leonard, m; Kennedy Creek, 0.6 mi upstream from US 101, 47.090 ° N, - 123.095 ° W, 8 February 2003, W. Leonard, m, f; same, but 47.087 ° N, - 123.091 ° W, 30 March 2003, mm; same but 47.090 ° N, - 123.095 ° W, 8 December 2004, m. Pacific Co.: Trap Creek, 1.1 mi north of State Route 12, 3 May 2003, W. Leonard, mm; Middle Nemah River drainage, WDFW Type N study basin, 3576 A 3300 Road, 46.468 ° N, - 123.809 ° W, 1900 ’ asl, 7 June 2006, C. Richart, m. Thurston Co.: Priest Point (Squaxin) Park, East Bay Drive Northeast, Olympia, 47.070 ° N, - 122.894 ° W, 100 ’ asl, 16 February 2003, W. Leonard, m; Wetland bedside Kennedydell Park, 46.987 ° N, - 122.970 ° W, 50, asl, 4 April 2004, W. Leonard, mm; Capitol State Forest, tributary to Kennedy Creek, 47.023 ° N, 123 ° 013 ’, 948 ’ asl, 13 September 2003, W. Leonard, mm; Capitol State Forest, unnamed tributary to Perry Creek, 47.062 ° N, - 123.069 ° W, 950 ’ asl, 17 October 2003, W. Leonard, m; Woodard Bay Natural Resource Conservation Area, 2 March 2001, W. Leonard, mm; McAllister Springs, 47.049 ° N, - 122.795 ° W, 23 February 2004, W. Leonard, mm, ff; McAllister Creek, 5 m south of Steelacom Road, 47.057 ° N, - 122.713 ° W, 100 ’ adl, 11 December 2004, W. Leonard, mm; Beach Trail, Evergreen State College campus, Olympia, 47.079 ° N, - 122.978 ° W, 100 ’ asl, 22 December 2003, m. Wahakiakum Co.: State Route 4 at milepost 23.7, 19 September 2003, W. Leonard, m; Allison Springs, Olympia, 47.048 ° N, - 122.983 ° W, 29 September 2003, W. Leonard, m; Rock Creek at Elochoman River, 46.276 ° N, - 123.280 ° W, 317 ’ asl, 10 January 2004, W. Leonard, C. Richart, mm, ff; Rock Candy Mountain Road, 1 mi south of US 101, Capitol State Forest, 28 June 2003, W. Leonard, mm, ff.	en	Shear, William A., Marek, Paul E. (2025): Additions to the millipede family Caseyidae Verhoeff, 1909. IV. Two new genera and three new species (Chordeumatida, Striarioidea, Caseyidae). Zootaxa 5631 (3): 533-547, DOI: 10.11646/zootaxa.5631.3.7, URL: https://doi.org/10.11646/zootaxa.5631.3.7
03C78796D84DA113FF1AF97EFC3BFECC.taxon	type_taxon	Type species: Opionoides cataracta Shear & Marek, new species. Monotypic.	en	Shear, William A., Marek, Paul E. (2025): Additions to the millipede family Caseyidae Verhoeff, 1909. IV. Two new genera and three new species (Chordeumatida, Striarioidea, Caseyidae). Zootaxa 5631 (3): 533-547, DOI: 10.11646/zootaxa.5631.3.7, URL: https://doi.org/10.11646/zootaxa.5631.3.7
03C78796D84DA113FF1AF97EFC3BFECC.taxon	diagnosis	Diagnosis: Distinct in the form of the gonopods (Figs 24 – 27) from all other caseyid genera. The anterior angiocoxite is distally crowned with an array of stout cuticular spines (not setae) and the large posterior angiocoxites, which project anteriorly between the anterior angiocoxites bear a complex array of feathery, fimbriate processes. Large, poorly sclerotized colpocoxites are present, and a small, fimbriate branch may represent a vestigial telopodite.	en	Shear, William A., Marek, Paul E. (2025): Additions to the millipede family Caseyidae Verhoeff, 1909. IV. Two new genera and three new species (Chordeumatida, Striarioidea, Caseyidae). Zootaxa 5631 (3): 533-547, DOI: 10.11646/zootaxa.5631.3.7, URL: https://doi.org/10.11646/zootaxa.5631.3.7
03C78796D84DA113FF1AF97EFC3BFECC.taxon	etymology	Etymology. The genus name is a Greek neologism, “ like Opiona ” and should be considered feminine in gender.	en	Shear, William A., Marek, Paul E. (2025): Additions to the millipede family Caseyidae Verhoeff, 1909. IV. Two new genera and three new species (Chordeumatida, Striarioidea, Caseyidae). Zootaxa 5631 (3): 533-547, DOI: 10.11646/zootaxa.5631.3.7, URL: https://doi.org/10.11646/zootaxa.5631.3.7
03C78796D84DA113FF1AF97EFC3BFECC.taxon	description	Description. As for the single known species, described below.	en	Shear, William A., Marek, Paul E. (2025): Additions to the millipede family Caseyidae Verhoeff, 1909. IV. Two new genera and three new species (Chordeumatida, Striarioidea, Caseyidae). Zootaxa 5631 (3): 533-547, DOI: 10.11646/zootaxa.5631.3.7, URL: https://doi.org/10.11646/zootaxa.5631.3.7
03C78796D84EA117FF1AFF2FFC7CFD24.taxon	description	Figs 22 – 29, 32	en	Shear, William A., Marek, Paul E. (2025): Additions to the millipede family Caseyidae Verhoeff, 1909. IV. Two new genera and three new species (Chordeumatida, Striarioidea, Caseyidae). Zootaxa 5631 (3): 533-547, DOI: 10.11646/zootaxa.5631.3.7, URL: https://doi.org/10.11646/zootaxa.5631.3.7
03C78796D84EA117FF1AFF2FFC7CFD24.taxon	materials_examined	Types. Male holotype, three male and two female paratypes from Golden and Silver Falls State Natural Area, 43.483 ° N, - 123.933 ° W, 96 m asl, Coos Co., Oregon, collected 27 May 2007 by C. Richard & A. Fusek. Parts of paratype males are mounted on SEM stub WS 38 - 5.	en	Shear, William A., Marek, Paul E. (2025): Additions to the millipede family Caseyidae Verhoeff, 1909. IV. Two new genera and three new species (Chordeumatida, Striarioidea, Caseyidae). Zootaxa 5631 (3): 533-547, DOI: 10.11646/zootaxa.5631.3.7, URL: https://doi.org/10.11646/zootaxa.5631.3.7
03C78796D84EA117FF1AFF2FFC7CFD24.taxon	etymology	Etymology. The species epithet, a Latin noun in apposition, “ waterfall, ” refers to the type locality.	en	Shear, William A., Marek, Paul E. (2025): Additions to the millipede family Caseyidae Verhoeff, 1909. IV. Two new genera and three new species (Chordeumatida, Striarioidea, Caseyidae). Zootaxa 5631 (3): 533-547, DOI: 10.11646/zootaxa.5631.3.7, URL: https://doi.org/10.11646/zootaxa.5631.3.7
03C78796D84EA117FF1AFF2FFC7CFD24.taxon	diagnosis	Diagnosis. As for the genus.	en	Shear, William A., Marek, Paul E. (2025): Additions to the millipede family Caseyidae Verhoeff, 1909. IV. Two new genera and three new species (Chordeumatida, Striarioidea, Caseyidae). Zootaxa 5631 (3): 533-547, DOI: 10.11646/zootaxa.5631.3.7, URL: https://doi.org/10.11646/zootaxa.5631.3.7
03C78796D84EA117FF1AFF2FFC7CFD24.taxon	description	Description. Male paratype. Length about 10 mm, width 1.0 mm. 30 rings (Fig. 32). Twenty-four ommatidia in triangular eyepatch. Color pale tan, heavily marked anteriorly and dorsally with purplish brown, pale tan areas around segmental setae. Segmental setae in straight row across posterior margin of metazonites. First legpair (Fig. 22) short, stout, with few flattened, spiral setae distal on femur, postfemur and tibia; tarsus with setal comb. Second legpair (Fig. 23) with gonapophyses (g) distally attenuate, curved, with long setae anteriorly, vas deferens and accessory pore not observed; telopodites (t 2) with five podomeres, as long as or slightly longer than gonapophyses, femora elongate. Third legpair (Fig. 23) coxae (cx 3) with narrow lobes slightly curved inward, setose, prominent tuft of apical setae. Third legpair telopodites with five podomeres, prefemur (pf 3) strongly expanded, flattened, tarsus minute. Lepairs four to seven not enlarged. Gonopods in lateral view (Fig. 24) with anterior angiocoxite (aac) broad, curved, bearing distal crown of many acute spines, not setae (Fig. 26); posterior angiocoxite (pac) large, spiculate, sheathing at least four flagellocoxites (f); colpocoxite (cc) saclike, weakly sclerotized. In mesal view, posterior angiocoxite (pac) projecting anteriorly between anterior angiocoxites, bearing many feathery branches and spicules; small fimbriate branch may represent vestigial telopodite (t). Ninth legpair (Fig. 28) with coxae (cx 3) having posterior humps and coxal processes with widely separated branches (cp); lateral branch short, stout, flattened, mesal branch longer, narrow, curved anteriorly. Ninth leg telopodites of single article but with deep sulcus that appears to divide them, deeply excavate mesally. Tenth legpair (Fig. 29) with broad sternum (s 10), coxae (cx 10) elongate, with stout distal, curved processes (cp), large coxal glands (cg); telopodites (t 10) reduced. Paratype female. Length about 11.0 mm, width 1.0 mm. Nonsexual characters as in male. Vulvae not modified. Records. Known only from the type locality.	en	Shear, William A., Marek, Paul E. (2025): Additions to the millipede family Caseyidae Verhoeff, 1909. IV. Two new genera and three new species (Chordeumatida, Striarioidea, Caseyidae). Zootaxa 5631 (3): 533-547, DOI: 10.11646/zootaxa.5631.3.7, URL: https://doi.org/10.11646/zootaxa.5631.3.7
03C78796D84EA117FF1AFF2FFC7CFD24.taxon	discussion	Notes. The pregonopodal leg modifications of this species are similar to those of Opiona species and related caseyid genera. However, the gonopods are unusual and unique, due to the spines crowning the distal crest of the anterior angiocoxite and the feathery branches of the posterior angiocoxite. While these branches may recall similar structures on the gonopods of ochrogrammatines, in detail they are very different and probably represent a parallel or convergent development. Unlike the foregoing genus, colpocoxites are present, as well as a small branch which may represent a vestigial telopodite. In addition, there are at least four and perhaps more flagellocoxites, which are a feature of Opiona gonopods, but not those of Paropiona. These are sheathed in the posterior angiocoxite as is the case in Opiona. The ninth legpair is also closer to the Opiona pattern, rather than Paropiona, with rather button-like telopodites. As noted by Gardner and Shelley (1989), some species of Opiona have a prominent sulcus in the single telopodite podomere of the ninth legpair which can give the impression that two podomeres are present instead of just one, and this is the case for Opionoides cataracta, sp. nov. The elongate coxae of the tenth legpair are not found in any Opiona species we have examined, but we have not seen them all.	en	Shear, William A., Marek, Paul E. (2025): Additions to the millipede family Caseyidae Verhoeff, 1909. IV. Two new genera and three new species (Chordeumatida, Striarioidea, Caseyidae). Zootaxa 5631 (3): 533-547, DOI: 10.11646/zootaxa.5631.3.7, URL: https://doi.org/10.11646/zootaxa.5631.3.7
