Petra sierwaldae Shear, Marek, Bond & Wesener 2022, new species
Creators: name: Shear, William A.
name: Marek, Paul E.
name: Bond, Jason E.
name: Wesener, Thomas
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Diplopoda
Chordeumatida
Striariidae
Petra
Petra sierwaldae

description: Petra sierwaldae Shear, Marek, Bond & Wesener, new species
Figs 1–14
Types: Male holotype, two male paratypes and three female paratypes from Beauty Creek, Panhandle National Forest, 47.6018°N, - 116.6405°W, collected 4 November 2004 by W. Leonard, C. Richart and J. Baugh; male paratype from Beauty Creek Road (FSR438), 1.3 mi SE of SR97, 698' asl, 47.6015°N, - 116.6579°W collected 18 October 2009 by W. Leonard and C. Richart; Beauty Creek, 2.5 mi E of Lake Coeur d'Alene, 3202' asl, 47.6124°N, - 116.6355°W, 14 April 2004, W. Leonard, J. Baugh; male paratype from Bumblebee Creek, Panhandle National Forest, 2240' asl, 47.6325°N, - 116.2965°W, 6 November 2004, W. Leonard, C. Richart, J. Baugh. All localities are in Kootenai County, Idaho, USA. Parts of a male paratype are on SEM stub WS36-16. All specimens, including SEM stubs, deposited in Field Museum of Natural History, Chicago IL, USA (FMNH).
Etymology. As for the genus, the specific epithet is a patronym in honor of Petra Sierwald.
Diagnosis. As for the genus, see above.
Description. Based on male holotype from Beauty Creek. Length, 3.8 mm, greatest width 0.56 mm. Twentyeight rings (collum + 26 leg-bearing rings + telson).
Head (Figs 1, 2, 5) densely setose, with single ommatidium (om, Fig. 2) on each side. Lateral corners of labrum (lab, Fig. 5) rounded. Mandibular stipes (m, Fig. 5) with distal, short, acute process.
Collum (col, Fig. 1) with distinct anterior rim, notched at position of lateralmost segmental seta (cn, Fig. 2), crests short, limited to posterior fourth of collum, sixth crest marginal.
Subsequent rings (Figs 1, 3) with crests extending full length of metazonite, subequal in height. Metazonital setae long, with brush-like tips.
Telson (tel, Fig. 4) short, lacking crests, lateral lobes suppressed but middle lobe obvious. Spinnerets directed posterioventrad. Paraprocts (pp, Fig. 4) with three setae, ornamented with elongate tubercles. Hypoproct (hp, Fig. 4) with two setae, similar tubercles.
First leg pair (L1, Fig. 5) encrassate, without needle-like setae, few flattened, twisted setae on distal podomeres. Second leg pair (L2, Fig. 1) reduced, femora clavate. Leg pairs 3–7 strongly encrassate, third leg pair (L3, Fig. 6) lacking coxal flasks; fourth leg pair (L4, Fig. 6) the largest, coxae slightly excavated anteriorly; coxae of fifth leg pair (L5, Fig. 6) enlarged, with blunt anterior lobes set with acute tubercles (Fig. 7); sixth and seventh leg pair coxae unmodified. Proximal segments of all legs ornamented with typical flattened setae (Fig. 8).
Gonopods (Figs 9, 10, 12, 13) with broad sternum (s, Fig. 9) bearing lobes extending laterally. Coxae (cx, Figs 9, 13) with 3–5 setae, long coxal process (cxp, Figs 10, 12, 13) parallels anterior angiocoxites (aac, 9, 10, 12, 13). Posterior angiocoxae (pac?, Fig. 12) sheaths single, large flagellocoxite (fc, Figs 12, 13). Colpocoxite (cc, Figs 10, 12, 13) as elongate, fimbriate, weakly sclerotized branch. Tips of gonopod elements insert into cavities in ninth leg pair telopodites (see Fig. 9). Ninth leg pair (Figs 11, 14) with weak, narrow sternum, coxae and telopodites appearing fused; coxal part with mesal group of acute setae, telopodite portion laterally heavily tuberculate, with setae somewhat ensiform, mesally a large, smooth lobe envelopes tips of gonopods. Tenth coxae unmodified, with gland openings.
Female paratype similar to male but lacking secondary sexual modifications, 4.2 mm long.
description: Published as part of Shear, William A., Marek, Paul E., Bond, Jason E. & Wesener, Thomas, 2022, The millipede family Striariidae Bollman, 1893. VII. Petra sierwaldae, n. gen., n. sp. a minute millipede from Idaho, USA (Diplopoda, Chordeumatida, Striariidae), pp. 287-293 in Zootaxa 5213 (3) on pages 289-290, DOI: 10.11646/zootaxa.5213.3.6, http://zenodo.org/record/7360003