Nearctomeris inexpectata, Wesener, Thomas, 2012

Wesener, Thomas, 2012, Nearctomeris, a new genus of Pill Millipedes from North America, with a comparison of genetic distances of American Pill Millipede Genera (Glomerida, Glomeridae), Zootaxa 3258, pp. 58-68 : 63-65

publication ID	https://doi.org/ 10.5281/zenodo.210225
DOI	https://doi.org/10.5281/zenodo.6167710
persistent identifier	https://treatment.plazi.org/id/B12887FD-FFAC-2B29-FF73-FF25FE60FEF8
treatment provided by	Plazi
scientific name	Nearctomeris inexpectata
status	sp. nov.

Treatment

Nearctomeris inexpectata View in CoL , new species

Etymology. inexpectata , adjective, meaning 'unexpected', referring to the surprise of the describer when he found a second, undescribed genus and species among the sample of Onomeris sinuata specimens.

Material examined. Holotype: 1 M, ZFMK MYR 008, USA, Alabama, Huntsville, Monte Sano State Park, under logs and in leaf litter next to limestone outcrops, NE shadow, 34°44'10.30" N, 086°30'00.10" W, leg. T. Wesener & H. Walsh, 30.iii.-01.iv.2010. Gen Bank # JQ 074186 View Materials

Paratypes: 1 F, ZFMK MYR 005, same data as holotype; 1 F, 1 imm. ZFMK MYR 010, same data as holotype; 4 imm., ZFMK MYR 011, same data as holotype; 1 F TWAL 16 FMNH-INS 0 0 0 0 0 73 489.

Other material. 2 M, 6 F, VMNH, USA, North Carolina, Macon County, Wayah Bald, Natahales, coll. RL Hoffman, 03.vi.1953 (together with 1 imm. M, 1 F Onomeris ); 4 F VMNH (labeled as 'Types' by R.L. Hoffman, not selected as types of N. inexpectata because they are female), Tennessee, Polk County, Tellico Gorge, coll. L. Hubricht, 11.vi.1953.

Diagnosis. Small-bodied (<6 mm), darkly colored ( Fig. 2 View FIGURE 2 A) pill-millipede. Co-occurs with Onomeris species. See key for a distinction between Nearctomeris inexpectata and different Onomeris species.

Description. Measurements: largest female of type series: 5.3 mm long, thoracic shield 2.6 mm wide, tergite 5 2.85 mm wide, thoracic shield 1.8 mm high. Holotype male fragmented due to dissection and tissue extraction, smaller than female.

General coloration ( Fig. 2 View FIGURE 2 A) blackish-brown, each tergite laterally with a lighter, central, almost white area (muscle insertion?). Head, antenna and legs dark brown. In the field, specimens are of a shiny appearance, resembling micro-gastropods.

Head with a setose labrum covered by eight marginal setae ( Fig. 2 View FIGURE 2 C). Lateral margins well-rounded. Head like tergites sparsely covered with minute setae ( Fig. 2 View FIGURE 2 D).

Ocellaria black, ocelli 6+1 (in smaller specimens also 5+1 or 4+2); lenses convex ( Fig. 3 View FIGURE 3 C).

Antennae with four large apical cones, antennomere 6 approximately 2 times as long as broad. Antennomere 3 as long as 1 and 2 combined ( Fig. 2 View FIGURE 2 C).

Organ of Tömösváry elongate, about 2.4–2.5 times as long as broad ( Fig. 2 View FIGURE 2 C).

Gnathochilarium ventrally without any peculiarities ( Fig. 2 View FIGURE 2 D), not dissected, endochilarium unknown.

Mandible ( Figs 3 View FIGURE 3 A, B) with large basal joints ( Fig. 2 View FIGURE 2 D). Inner tooth 5-combed; seven rows of pectinate lamellae; large intermediate area consisting of sclerotized, finely combed teeth between pectinate lamellae and molar plate ( Fig. 3 View FIGURE 3 B). Condylus absent, or a barely detectable 'bump' ( Fig. 3 View FIGURE 3 A).

Collum with two transverse striae ( Fig. 2 View FIGURE 2 F), covered sparsely with minute, short hair like the rest of the tergites.

Thoracic shield with weakly developed schism, its caudal edge not protruding above tergal contour ( Fig. 2 View FIGURE 2 E). Weak, almost slit-like impression present in front of schism. Shield with few transverse striae, of which only one crosses the dorsum ( Fig. 2 View FIGURE 2 E). Two more incomplete striae present dorsally ( Fig. 2 View FIGURE 2 E: str2 & str3) The complete stria and one short stria lie below, several inside, and two very short ones above the impression ( Fig. 2 View FIGURE 2 E). Thoracic shield, like other tergites, sparsely covered with numerous minute pits ( Fig. 2 View FIGURE 2 E), a short seta arising at each pit.

Following tergites 3–11 covered with numerous short setae, usually inserting in pits. Anterior margin of tergites with a well rounded marginal ridge ( Fig. 2 View FIGURE 2 E). Tergites laterally with a single discernable stria, lateral edges not projecting posteriorly ( Fig. 2 View FIGURE 2 A).

Mid-body legs ( Fig. 3 View FIGURE 3 G) at mesal margin with numerous setae. Femur 2.0 times longer than wide, tarsus slender, tapering towards apex, 3.9–4.0 times longer than wide. Tarsus with 9–12 ventral spines, one apical spine, and additional 6 or 7 dorsal spines. Claw long and slender.

Male anal shield well-rounded, without any kind of notch or a concave posterior margin ( Fig. 2 View FIGURE 2 B).

Male first leg pair ( Fig. 4 View FIGURE 4 A) similar to mid-body legs, but coxae mesally elongated into a process carrying a single long spine. Tarsus with only seven ventral spines.

Male second leg pair ( Fig. 3 View FIGURE 3 D) similar to mid-body legs, but coxae mesally with single spine of mediumlength. Femur slender, 3.0 times longer than wide. Gonopore covering mesal 1/3 of coxa.

Male gonopore ( Figs 4 View FIGURE 4 E, F) consisting of a single opening covered by an apparently membranous operculum. Bursa apico-mesally with a field of long setae.

Male leg 17 ( Fig. 4 View FIGURE 4 B) particularly strongly reduced, with a low, broad, rounded coxal lobe and a 3-segmented vestigial telopodite. First and second podomere with a mesal, third podomere with an apical spine.

Male leg 18 ( Fig. 4 View FIGURE 4 C) less strongly reduced, with a syncoxial notch, coxite mesally elongated into a short process carrying a large spine. Apically of syncoxite with a 4-segmented telopodite, podomere 4 with strongly developed spine ( Fig. 3 View FIGURE 3 A).

Telopod ( Figs 4 View FIGURE 4 D–G) strongly robust, with a high, rounded, subtrapeziform ( Figs 4 View FIGURE 4 F, G) syncoxital lobe flanked by setose, apically simple horns. Inner horns mesally with single spine whose base is curved 90°. Prefemur with strongly developed trichostele. Femur with trichostele approximately a third of the length of the prefemoral one, posteriorly with very large, well-rounded process (= distal finger). Femur with a field of sclerotized teeth located centrally on the posterior face of finger ( Fig. 4 View FIGURE 4 D). Tibia, tarsus, and distal finger forming a chela ( Fig. 4 View FIGURE 4 D). Tibia with a small field of sclerotized teeth at its base ( Fig. 4 View FIGURE 4 D). Tarsus long, massive, basally curved 45–65 degrees towards syncoxite ( Fig. 4 View FIGURE 4 E). Apex of tarsus well-rounded, posteriorly with long spine. Telopod posteriorly only sparsely covered with few, isolated setae, on anterior side glabrous.

Intraspecific variation. Specimens from North Carolina (VMNH) show the following measurements: small male: 4.9 mm long, at thoracic shield 2.5 wide, with 5+1 ocelli, largest female 5.6 mm long, at thoracic shield 2.7 wide, with 6+1 ocelli.