Orthorhachis catherinae, Mesibov, 2008

Mesibov, Robert, 2008, The millipede genera Gephyrodesmus Jeekel, 1983 and Orthorhachis Jeekel, 1985 in southeastern Australia, a new Lissodesmus Chamberlin, 1920 from Victoria, and observations on male leg setae, spinnerets and metatergite sculpture (Diplopoda: Polydesmida: Dalodesmidae), Zootaxa 1790, pp. 1-52 : 20-22

Orthorhachis catherinae n. sp.

Figs. 6C, 13; map Fig. 31

Holotype: Male. Kosciuszko National Park , NSW, 1 km NW of junction of Long Plain Road and Snowy Mountain Highway , 35º42'49"S 148º31'26"E, 1320 m, edge of forest/alpine vegetation boundary, in fine leaf litter, 14 November 2006, C.A. Car. In AM, KS 103044.

Paratypes: In AM: 1 male , Mt Kosciuszko , NSW, 9 February 1979, D.K. McAlpine & B.J. Day, KS36825 ; 1 male , details as for holotype, KS 103045 .

Other material examined: None available.

Diagnosis: Gonopod telopodite with solenomere divided into mediolaterally expanded basal section and narrow distal section, and with medial process bearing a short posterior projection with expanded tip. Posterior sternites with median tab-like structure along posterior edge.

Description: As for the genus. Male approximate measurements: length 21 mm, midbody prozonite diameter 1.7 mm, midbody width across paranota 2.4 mm. Holotype near-uniform medium brown. Antennal sockets separated by just under 2X a socket diameter. Antennae slender, relative lengths of antennomeres (2,3)>5>(4,6). Collum D-shaped with slightly produced posterior corners; wider than head but narrower than tergite 2. Metatergite sculpture distinct, Pattern A ( Fig. 6C). Paranota with anterior and lateral margins forming a single smooth, convex curve ( Fig. 6C). Legs slender, leg 6 tarsus 1.7X as long as femur. Brush setae with forked tips. Sternites of posterior rings (10–18?) with a small, median, rounded, two-lobed tab on posterior edge, less evident on anterior rings in the tab-bearing set.

Gonopod aperture ovoid, slightly wider than long, about one-third the width of the ring 7 prozonite, rim raised posterolaterally. Telopodite ( Fig. 13) short, proximal portion cylindrical, slightly flared at base; long setae on posterolateral surface to just over one-third telopodite height; branching beginning at between onehalf and two-thirds telopodite height. Basal section of solenomere bending slightly posteriorly at base, swelling medially and laterally to about half telopodite width. Distal section of solenomere arising from posterolat- eral corner of swollen tip of basal section, narrow, cylindrical and tapering, bending first posteriorly and laterally and curving anteriorly, then posteriorly near the tip, the posterior surface roughened on the anterior curve. Medial process cylindrical at base, as wide as solenomere and well-separated from it, C-shaped (concave posteriorly); expanded at tip with broad, shallow, terminal depression; terminating at about two-thirds height of distal section of solenomere; with narrow rod-like projection arising at about two-thirds medial process height, directed posteriorly and slightly laterally, slightly expanded at tip, terminating posteriorly no further than anterior curve of distal solenomere section.

Female not yet recognised.

Distribution: Known only from two high-elevation sites in Kosciuszko National Park, southeastern New South Wales ( Fig. 31). One site is close to the only known O. cavatica locality.

Etymology: For Catherine Car, student of Paradoxosomatidae and collector of the holotype.