Orthorhachis celtica, 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 : 22-24

Orthorhachis celtica n. sp.

Fig. 15; map Fig. 32A

Holotype: Male. Oakes State Forest , Horseshoe Road, 2 km NNE of Killekrankie Mountain, NSW, 30º31'22"S 152º32'59"E, 760 m (GE), 11–24 November 1999, M. Gray, G. Milledge & H. Smith, pit traps, Hotspots NE NSW site 16. In AM, KS61556 ; anterior rings in genitalia vial.

Paratype: In AM: 1 male , Belbucca Road , Irishman State Forest, NSW, 30º32'58"S 152º40'14"E, 520 m (GE), 11–24 November 1999, G. Milledge & H. Smith, pit traps, KS 103046 .

Other material examined: None available.

Diagnosis: Gonopod telopodite with solenomere strongly tapering from wide base, and with third telopodite process on anterior surface, the process partly enclosed within fold of medial branch of telopodite and with small lateral teeth.

Description: As for the genus. Male approximate measurements: length 14 mm, midbody prozonite diameter 1.3 mm, midbody width across paranota 1.8 mm. Body discoloured, near-uniform light brown. Antennal sockets separated by 2.5X a socket diameter. Antennae slender, relative lengths of antennomeres 3>(2,6)>(4,5). Collum D-shaped with rounded corners, narrower than head and tergite 2. Metatergite sculpture very indistinct, possibly Pattern A. Paranota with anterior margin convex, lateral margin more or less parallel to long axis of body. Legs slender, leg 6 tarsus 1.7X as long as femur. Brush setae with forked tips.

Gonopod aperture ovoid, slightly wider than long, about one-third the width of the ring 7 prozonite, rim raised posterolaterally. Telopodite ( Fig. 15) short, broad at base, swollen laterally and posteriorly at one-third to one-half telopodite height; sparse long setae on posterolateral surface to one-third telopodite height; branching beginning at two-thirds telopodite height. Solenomere broad at base, directed slightly posteriorly, rapidly tapering at half solenomere height and curving laterally, with a small tooth-like projection on distomedial surface just below tip. Medial process well-separated from solenomere, slightly C-shaped (concave posteriorly), expanded just above base and somewhat flattened mediolaterally, folded to partly enclose third telopodite process laterally; distally truncate and terminating just proximal to solenomere tip, with a small, short posterior projection at about three-quarters length of medial process. Third telopodite process rod-like, bluntly pointed, with lateral edge produced near base; arising just medial and basal to medial process origin with cuticular ridge extending basally on anteromedial surface of telopodite; process directed parallel to solenomere and terminating at about half solenomere height; with minute teeth on anterolateral surface to onethird process height; partly enclosed medially by fold of medial process. Prostatic groove running laterodistally for short distance on anterior surface of telopodite, then turning distally before running laterodistally lateral to third telopodite process to solenomere base, then following curves of solenomere to tip.

Female not yet recognised.

Distribution: Known only from two sites ca. 12 km apart, south of Dorrigo in northeastern New South Wales, between localities for O. kerewong and O. serrata ( Fig. 32A)

Etymology: Latin celticus, of the Celts, adjective, for the two known localities, Irishman State Forest and Killekrankie Mountain.