Tigraria oregonensis Shear & Marek, 2023

Shear, William A. & Marek, Paul E., 2023, The millipede family Striariidae Bollman, 1893. VIII. Three new genera and four new species of minute millipedes from Oregon and Washington, USA (Diplopoda, Chordeumatida, Striarioidea), Zootaxa 5264 (3), pp. 323-340 : 332

Tigraria oregonensis Shear & Marek , n. sp.

Figs 26–34 , 57–59

Types: All specimens deposited in CAS. Male holotype, two male and four female paratypes from Umatilla National Forest, 0.2 mi E of Tiger Saddle, 45.944417°N, - 118.009433°W, 4766′ asl, collected 24 October 2003 by W. Leonard .

Diagnosis. As for the genus, see above.

Etymology. The species name, an adjective, refers to the occurrence of the species in the state of Oregon.

Description. Male paratype from Tiger Saddle. Length 4.3 mm, width 0.5mm. Twenty-eight postcephalic rings. Color white, with single black ommatidium on each side of head. Antennae robust, clavate; fifth antennomere longest, widest. Head ( Fig. 26 ) except for labrum covered with fine setae and small tubercles. Labrum not flattened, tapering, corners rounded (lab, Fig. 26 ). Mandibular stipes (m, Fig. 26 ) with serrate edge suppressed, distally flattened and extended. Collum (col, Fig. 27 ) ornamented by closely set small tubercles, becoming indistinct crests only mesally on most posterior part. Metazonites with twelve subequal crests ( Fig. 28 ); metazonital setae ( Fig. 29 ) long, prominent, with longitudinal grooves and feathered tips occupying about 1/3 length of seta. Telson with lateral lobes practically obsolete, median lobe slightly projecting; spinnerets directed posteriorly. Legs with specialized flattened setae with median ridges and long, filamentous extensions.

The following secondary sexual characters occur in males. Head ( Fig. 26 ) frontally flattened with slight swellings below antennal sockets; labrum with few setae, distal corners rounded. Mandibular stipes ( Fig. 26 ) with weakly serrate anteriodistal margin, prominent blunt distal tooth. First legpair (L1, Fig. 26 ) enlarged, femora curved, lacking needle setae, distal podomeres with few long, flattened setae ventrally. Second legpair (L2, Fig. 26 ; Fig. 30 ) shorter than first, openings of vas deferentia separate (vd, Fig. 30 ), subtended by long, flattened, ribbon-like setae, femur distally swollen. Third legpair (L3, Fig. 26 ; Fig. 31 ) less robust than first two, coxal flasks absent but coxae complexly excavate; tarsi with special sensory array including comb setae and recessed pore plate. Fourth legpair the largest; prefemora and femora of usual proportions. Fifth coxae (cx5, Fig. 32 ) with prominent projecting knobs densely set with cuticular teeth, sixth and seventh legpairs enlarged; seventh coxae unmodified. Tenth coxae with glands, not modified or enlarged.

Gonopods ( Figs 33 , 57, 58 ) separate from prominent, transverse sternum (s, Fig. 33 ), coxae large (cx, Fig. 33 ), with five or six setae. Anterior angiocoxites curved, distally attenuated (aac, Figs 33 , 57, 58 ), posterior margin not fimbriate, and with long, robust, curved branch arising near base and appearing almost to be articulated. Posterior angiocoxites (pac, Figs 33 , 57, 58 ) smaller than anterior ones, fimbriate, divided into basal and distal parts, sheathing short, curved single flagellum or flagellocoxite (f, Figs 57, 58 ). Colpocoxites (cc, Figs 57, 58 ) membranous-fimbriate, not much reduced. Ninth legs ( Fig. 34 , 59 ) free from sternum, coxae and telopodites fused, coxae with prominent anterior poorly sclerotized lobe lacking obvious gland pore—also with strongly curved single process (cxp, Fig. 34 ) broad at base, distally hooked, with deep recess (pore?) at base; telopodites strongly flattened, setose, with ornament of pointed tubercles (as on other legs). Tenth coxae with pores, not modified.

Females similar in all nonsexual characters.

Notes. Despite the great distance separating their type localities, this species shares some significant characters with Petra sierwaldae, from Idaho, specifically the lack of flasks on the male third coxae and the modified coxae of legpair 5. The gonopods and second and ninth legpairs, however, are very different, justifying a new genus for this Oregon species. Tigraria oregonensis gonopods, however, are more conforming to the plan found in species of Miniaria , with a branched anterior angiocoxite and a two-part posterior angiocoxite. The male ninth legs also suggest a close relationship with Miniaria . The mandibular stipes is unique in that instead of a tooth-like process distally, the stipes is flattened into an extended lamella. Parts of a specimen from near Tiger Saddle are on SEM stub WS35-17.

Figures

FIGURES 24–30. Male striariid millipedes. Figs. 24, 25. Miniaria richarti n. gen., n. sp., male. 24. Gonopods of specimen from Pin Creek, ventral view. 25. Legpair 9 and coxae 10 of specimen from Kennedy Creek, ventral view. Figs. 26–30. Tigraria oregonensis n. gen., n. sp. male. 26. Head and first 3 legpairs, ventral view. 27. Collum, lateral view. 28. Pleurotergites 13, 14, dorsal view. 29. Segmental seta. 30. Left leg 2, ventral view. Abbreviations: aac, anterior angiocoxite; cc, colpocoxite; col, collum; cx, coxa of gonopods; cx (numeral), coxa of numbered legpair; L (numeral), numbered legpair; lab, labrum; m, mandibular stipes; numeral, ring numbers; s, sternite of gonopods; vd, opening of vas deferens.

FIGURES 31–34. Tigraria oregonensis n. gen., n. sp. male paratype. 31. Coxae of third legpair, ventral view. 32. Coxae of fifth legpair, ventrolateral view. 33. Gonopods, ventral view. 34. Legpair 9, anterior view. Abbreviations: aac, anterior angiocoxite; cx, coxa; cx (numeral), coxa of numbered legpair; cxp, coxal process; pac, posterior angiocoxite; s, sternum of gonopods; s9, sternum of legpair 9; t9, telopodite of leg 9.

FIGURES 55–61. Gonopods and ninth legs of male striariid millipedes. Figs. 55, 56. Miniaria richarti n. gen., n. sp. 55. Ninth legpair of specimen from Elochoman River Road, anterior view. 56. Left ninth leg of specimen from Hospital Creek, anterior view. Figs. 57–59. Tigraria oregonensis n. gen., n. sp., male paratype; 57. Right gonopod, mesal view. 58. Same, lateral view. 59. Right ninth leg, anterior view. Figs. 60, 61. Kingaria prattensis n. gen., n. sp., male holotype. 60. Right gonopod, lateral view. 61. Left ninth leg, anterior view. Abbreviations: aac, anterior angiocoxite; cc, colpocoxite; cx, coxa; cxp, coxal process; f, flagellum; pac, posterior angiocoxite; t9, telopodite of ninth leg.