Onomeris sinuata ( Loomis, 1943 ) Loomis, 1943

Wesener, Thomas, 2010, Revision of the American Pill Millipedes I: Onomeris and Trichomeris (Diplopoda, Glomerida, Glomeridae), Zootaxa 2725, pp. 28-40 : 36-38

Onomeris sinuata ( Loomis, 1943) new combination

( Figures 4 & 7 )

Trichomeris sinuata Loomis, 1943: 374

Chamberlin & Hoffman 1958: 13; Hoffman 1999: 18 (list species name).

Material examined: Type material: 1 male holotype, in excellent condition except that leg 18 is missing ( MCZ 88115). U.S.A., Alabama, Madison County, Monte Sano State Park 10 km E of Huntsville, along pipeline trail below summit escarpment, coll. L. Hubricht, 12.iv.1941.

Other material examined: 2 M, 4 F (FMNH-INS 56316). Same locality as above, but next to limestone outcrops, NE shadow, 34º44'10.30" N, 086º30'00.10" W, coll. T. Wesener & H. Walsh, 30.iii.2010; 2 M, 1 F, same data as previous, sent as vouchers to the MNHN; 1 M, 1 F, same data as previous, sent as vouchers to the ZFMK; 5 M, 4 F, (FMNH-INS 56302), U.S.A., Virginia, Lee County, Cumberland Gap NP, trail to Skylight Cave, coll. W. A. Shear, 10.vii.1972, dry litter near log; 3 M, 8 F ( VMNH). U.S.A., Tennessee, Monroe County, River Bluff, 1.5 miles E Tellico Plain, coll. C. Hubricht, 23.V.1962

Diagnosis: Differs from O. underwoodi and O. australora in presence of a trichostele on the tibia of the telopod ( Fig. 7 C), a basally wide, triangular tibial process ( Fig. 7 D); the presence of small coxal lobes on the 17th leg pair of the male ( Fig. 7 A), and anal shield very weakly concave medially at caudal edge.

Redescription: Length of non-stretched but unrolled specimens of both sexes ca 4–5 mm, width 2.2–2.8 mm General coloration Dark brown with laterally lighter grey markings. Tergites 2–11 laterally on metazona with oval greyish-white area, which does not reach margins of tergite. Appendages dark brown.

Antenna: third antennomere as large as 2 x second, sixth antennomere as large as first, second, fourth and fifth combined, the latter 2.5 times longer than wide.

Male anal shield at posterior margin weakly concave.

Male 17th leg with weakly developed coxal lobe ( Fig. 7 A)

Male 18th leg with fused coxite and four podomeres, shape typical for genus ( Fig. 7 B).

Telopod as in the genus description, with basally wide, apically slender, triangular tibial process and a short tibial trichostele ( Figs 7 C, D). Subcoxital lobe well-rounded ( Fig. 7 C).

Remarks: The original description of O. sinuata as the type species of Trichomeris Loomis, 1943 is based on erroneous descriptions and drawings. The drawings of the male leg pair 17 as well as the telopod published in the original description by Loomis disagree with the telopod present in the dissected holotype and with those of the new specimens collected at the original type locality. According to the original description ( Loomis 1943: fig. 1), the femur does not feature a trichostele, nor does the tibia. Furthermore, the tibial process of the telopod in Loomis’ original illustration is shorter than it is in the original holotype. The holotype of O. sinuata closely resembles O. underwoodi and O. australora and therefore allows the placement of this species into Onomeris .

To make matters even more complicated, a second, still undescribed genus of pill millipede occurs sympatrically with O. sinuata at Monte Sano State Park, Alabama. However, the possibility that the erroneous drawings by Loomis (1943) could be based on this undescribed genus can be ruled out, since the telopods of the undescribed genus are very distinct from both the original drawings of Trichomeris and the telopods of Onomeris and show little similarity with those of the only other known American Glomerida genus, Glomeroides (see illustrations in Silvestri 1929, Shear 1986, Wesener & VandenSpiegel 2009).

Figures

FIGURE 4. Onomeris sinuata (Loomis, 1943) n. comb. (FMNH-INS 56316) SEM. A: midbody tergite, dorsal view, anterior margin below; B: detailed view of tergite groove with seta. Abbreviation: th-rd = toothed ridge on anterior margin of tergite.

FIGURE 7. Onomeris sinuata (Loomis, 1943) n. comb. topotype (FMNH-INS 56316). A: rudimentary male 17 th leg, anterior view; B: 18 th leg of male; C: telopod pair, anterior view; D: left telopod, posterior view. Scale bars = 1 mm.