Nannaria sigmoidea (Hennen & Shelley, 2015)

Means, Jackson C., Hennen, Derek A. & Marek, Paul E., 2021, A revision of the minor species group in the millipede genus Nannaria Chamberlin, 1918 (Diplopoda, Polydesmida, Xystodesmidae), ZooKeys 1030, pp. 1-180 : 1

Nannaria sigmoidea (Hennen & Shelley, 2015) Vernacular name: "The Sigmoid Gonopod Twisted-Claw Millipede" Fig. 112

Mimuloria dilatata sigmoidea Hennen & Shelley, 2015: 1-15, figs 20, 21.

Nannaria sigmoidea : Means et al. 2021: S72.

Material examined.

Holotype: United States - Tennessee • ♂; Meigs County, c.a. 7.2 km S Decatur, along country road 4274, 0.8 km from junction of Tennessee highway 58; [35.4378°N, - 84.9140°W]; 14 Oct. 1978; R. M. Shelley, W. B. Jones leg.; NCSM NCSM27946. For detailed collection data see Suppl. material 7.

Diagnosis.

Adult males of N. sigmoidea are distinct from other Nannaria , including the nearby N. blackmountainensis sp. nov. and Nannaria sp. nov. ‘Cratagae’ ( Nannaria wilsoni species group), based on the following combination of characters: Gonopods. Gonopodal acropodite simple and gently curving anteromedially, not straight as in Nannaria sp. nov. ‘Cratagae’ or with medial swelling as in N. blackmountainensis sp. nov. Acropodite with prominent, rounded lateral flange near tip (Fig. 112A , red arrow), not hooked as in N. blackmountainensis sp. nov. or lacking as in Nannaria sp. nov. ‘Cratagae.’ Acropodite tip directed posteriorly, not dorsally as in N. blackmountainensis sp. nov. Telopodite basal zone subequal to length of prefemoral process, not ca. 1/2 length as in N. blackmountainensis sp. nov. or ca. 1/3 length as in Nannaria sp. nov. ‘Cratagae.’ Prefemur with prefemoral process bent at 90° angle at halfway point, directed medioventrally, not straight, acicular as in N. blackmountainensis sp. nov. and Nannaria sp. nov. ‘Cratagae.’ Prefemoral spine reduced to small, blunt lobe at base of prefemoral process (Fig. 112A , red triangle), not fused as a small ridge as in N. blackmountainensis sp. nov. or lacking as in Nannaria sp. nov. ‘Cratagae.’ Color. Color in life unknown.

Measurements.

♂ holotype (NCSM, NCSM27946): BL = 36.1, CW = 5.0, IW = 3.0, ISW = 1.1, B11W = 6.0, B11H = 3.8.

Variation.

No known variation.

Distribution.

Known only from the type locality (Tennessee: Meigs County; Suppl. material 7; Fig. 129 ). Distribution area: N/A; status: MRE.

Ecology.

Hennen and Shelley (2015) note that only that the type specimens were collected from the east side of the Tennessee River.

Etymology.

Hennen and Shelley (2015: 15) stated that "[t]he subspecific name denotes the overall sigmoidal curvature of the prefemoral process, which also passes through numerous vertical planes."

Note on clade membership.

No specimens of Nannaria sigmoidea were collected for this study. Nannaria sigmoidea shares gonopodal characters with members of the Nannaria ambulatrix clade, such as a prominent lateral flange on the acropodite tip, a prefemoral process bent at 90°, and crossing of the acropodites in the medial view (found in N. ambulatrix sp. nov. and N. botrydium sp. nov.). However, due to the wide geographic separation between N. sigmoidea and the Nannaria ambulatrix clade (> 270 km), and the presence of these characters in a member of the Nannaria minor clade ( N. kassoni sp. nov.), the phylogenetic placement of N. sigmoidea in a clade is uncertain.

Type locality.

United States, Tennessee, Meigs County, c.a. 7.2 km S Decatur, along country road 4274, 0.8 km from junction of Tennessee highway 58.

Notes.

In the original publication, Hennen and Shelley (2015: 15) designate a male holotype collected by R. M. Shelley and W. B. Jones on October 14, 1978.

Figures

Figure 112. Nannaria sigmoidea holotype ♂ (NCSM NCSM 27946) left gonopod A anterior view; red arrow indicates lateral flange; red arrow indicates reduced prefemoral spine B medial view C posterior view. Scale bar: 0.5 mm.

Figure 129. Distribution map of Nannaria minor species group collection localities west of the Appalachians.