Orthorhachis yabbra, 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 : 46-48

Orthorhachis yabbra n. sp.

Fig. 30; map Fig. 32B

Holotype: Male. 1 male, Yabbra State Forest , NSW, 2 April 1992, collector unknown. In AM, KS36844 .

Paratypes: In AM: 2 males , Yabbra State Forest , NSW, 27 February 1992, M. Gray & D. Charley, KS36833 .

In QM: 2 males, ' The Head', via Killarney, Qld, 1974–75, G. & S. Monteith, rainforest, pitfall 22B, S83693 .

Other material examined: In AM: 1 male, 1 stadium 7 female, Acacia Plateau and Wilsons Peak area, Kooreelah State Forest , NSW, 28º16'S 152º27'E, 11 December 1988, A.P. Smith, H.B. Hines, D. Pugh & P. Webber, pitfall trap AP7, subtropical rainforest, sheltered slope, Focal Peak Survey, UNE, KS39398 ; 1 male, Goanna Creek Road, 1.8 km from junction with Sandy Creek Road, Richmond Range State Forest, NSW, 28º36'S 152º42'E, 4 February–9 April 1993, M. Gray & G. Cassis, pitfall 04 AG, KS94870 ; 1 male, same details but Bennetts Road , ca. 10 km W of Urbenville, Beaury State Forest, NSW, 28º25'S 152º27'E, pitfall 01 BG, KS94879 ; 1 male, same details but Goanna Creek Road, Richmond Range State Forest, NSW, 28º37'S 152º42'E, KS 103054 .

In QM: 1 male, Plateau S of ' The Head' , via Killarney, Qld, 1974–75, G. & S. Monteith, rainforest, pitfall 21B, S83692 ; 1 male, same details but Cunninghams Gap, Qld, pitfall 31A, S83694 ; 1 male, Teviot Falls via Boonah, Qld, 1975–76, G. & S. Monteith, rainforest, pitfall 58, S83695 ; 1 male, Mt Clunie via Woodenbong, NSW, 1975–76, G. & S. Monteith, rainforest, pitfall 49A, S83696 ; 1 male, 2 females, Lions Road , Richmond Gap via Grevillea, NSW, 1978–79, G. Monteith, rainforest, pitfall 92, S83697 ; 1 male, 1 female, Atrichornis Track , Gibraltar Range National Park, NSW, 1980–81, G. Monteith, rainforest, pitfall 105, S83698 .

Diagnosis: Gonopod telopodite bent posterodistally above pronounced constriction at one-third telopodite height; anterior surface with line of evenly spaced teeth; medial process well separated from solenomere base, forked, with lateral branch flexed basally.

Description: As for the genus. Male/female approximate measurements: length 16/ 17 mm, midbody prozonite diameter 1.4/ 1.5 mm, midbody width across paranota 2.5/ 2.7 mm. In alcohol, well-coloured specimens near-uniform medium brown. Antennal sockets separated by 2X a socket diameter. Antennae slender, relative lengths of antennomeres 2>(3,6)>(4,5). Collum D-shaped, as wide as head and narrower than tergite 2. Metatergite sculpture very indistinct, apparently Pattern A. Paranota with anterior margin slightly convex; lateral margin very slightly convex. Legs slender, leg 6 tarsus 1.6X as long as femur. Brush setae with forked tips.

Gonopod aperture ovoid, as wide as long, one-third the width of the ring 7 prozonite, rim raised posterolaterally. Telopodite ( Fig. 30) short, base swollen and with long setae on posterolateral surface; telopodite abruptly constricted at about one-quarter telopodite height, more or less cylindrical, curving posteriorly from anterior portion of base, with row of ca. 6 well-spaced, small, rounded teeth along anterior surface from about one-half telopodite height to just above branching point; branching beginning at between two-thirds and three-quarters telopodite height. Solenomere thin, cylindrical, tapering gradually, directed first posterodistally, then curving distally, tip truncate. Medial process not closely applied to solenomere base, very short, divided; medial portion directed posterodistally and with broadly rounded tip, lateral portion finger-like, curving posterobasally with rounded tip. Prostatic groove running laterodistally for short distance on anterior surface of telopodite, then distally, then laterodistally on lateral side of anterior row of teeth to solenomere, and terminating at solenomere tip.

Female slightly larger than male, legs not swollen. Genital aperture with posterior margin barely raised. Cyphopods not examined.

Distribution: Known from ca. 5000 km 2 across the border between southeastern Queensland and northeastern New South Wales, from Cunninghams Gap south ca. 170 km to the Gibraltar Range ( Fig. 32B). Overlaps in range with O. monteithi and O. serrata , possibly with O. kerewong ; possibly parapatric with O. pallida near Cunninghams Gap.

Etymology: Noun in apposition, for the type locality, Yabbra State Forest.

Remarks: O. yabbra varies a little in size across its range.