Orthorhachis inflata, 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 : 30-31

Orthorhachis inflata n. sp.

Fig. 19; map Fig. 32A

Holotype: Male. Wilson River Reserve via Bellangty, NSW, 31º12'S 152º28'E, November 1966, D.K. McAlpine. In AM, KS94159 .

Paratypes: In AM: 1 male , details as for holotype, KS94152 ; 1 male , details as for holotype, KS94160 ; 1 male, 1 female , Fifes Knob Road , ca. 3 km from Fifes Fire Trail, Carrai State Forest, NSW, 30º54'S 152º22'E, 4 February – 9 April 1993, M. Gray and G. Cassis, 38 CM, KS94877 .

In MV: 1 male, Barrington Tops, NSW, January 1926, C. Barrett, K-10688 .

Other material examined: None available.

Diagnosis: Gonopod telopodite with large anterior swelling, with solenomere extending anteriorly above a distinct 'elbow', and with medial process lying posterior to solenomere, terminating in three large lobes and with a dentate lateral margin.

Description: As for the genus. Male/female approximate measurements (see below, Remarks): length 19/ 18 mm, midbody prozonite diameter 1.4–1.6/ 1.7 mm, midbody width across paranota 2.1–2.5/ 2.4 mm. Body discoloured, near-uniform light brown. Antennal sockets separated by 2X a socket diameter. Antennae slen- der, relative lengths of antennomeres 3>(2,6)>(4,5). Collum D-shaped, posterior margin slightly emarginate on either side, as wide as head and narrower than tergite 2. Metatergite sculpture fairly distinct, Pattern A. Paranota with anterior margin convex, lateral margin more or less parallel to long axis of body. Legs slender, leg 6 tarsus 1.5X as long as femur. Brush setae with forked tips.

Gonopod aperture ovoid, slightly wider than long, one-half the width of the ring 7 prozonite, rim raised posterolaterally. Telopodite ( Fig. 19) short, broad at base; long setae on posterolateral surface to one-third telopodite height; branching beginning at between one-half and two-thirds telopodite height. Telopodite basally with a large, rounded anterior swelling from about one-quarter to about one-half telopodite height, and with a small, thin flange with a few marginal teeth on medial surface at the same level as swelling. Solenomere arising anteriorly and slightly laterally, curving slightly laterally, then turning abruptly anteromedially at a distinct 'elbow', then tapering and curving tightly posteriorly at the tip in a plane at right angles to telopodite axis. Medial process arising posteriorly and slightly medially, broad than solenomere at base, anteroposteriorly flattened with lateral margin toothed, expanding distally and terminating just below level of solenomere 'elbow', the distal margin divided into three lobes: a broad lateral projection with a laterobasally directed, bluntly rounded tip; a small, truncate central projection; and a small, bluntly pointed medial projection, with a deep cleft between central and medial projections. Prostatic groove running laterodistally for short distance on anterior surface of telopodite, then distally, then abruptly laterodistally above anterior swelling of telopodite, and following curves of solenomere to tip.

Female with legs not swollen. Posterior margin of genital aperture slightly raised in low, convex arc. Cyphopods not examined.

Distribution: Known from three sites in northeastern New South Wales over a linear range of ca. 150 km ( Fig. 32A). May co-occur with the much smaller O. weiri in the Barrington Tops.

Etymology: Latin inflatus, swollen, adjective, for the large swelling on the anterior surface of the gonopod telopodite.

Remarks: Body sizes given in the description are for partly macerated specimens and are highly approximate.