Talomius weldensis, Mesibov, Robert, 2018

Mesibov, Robert, 2018, Cambaloid millipedes of Tasmania, Australia, with remarks on family-level classification and descriptions of two new genera and four new species (Diplopoda, Spirostreptida), ZooKeys 827, pp. 1-17 : 1

Talomius weldensis sp. n. Figs 3, 4

Holotype.

Male, dissected, with pieces in genitalia vials (see Remarks), Mt Weld altitudinal transect, Tasmania, - 42.9981 146.6167 ± 100 m (originally UTM 55G "468762 5239322", GDA94 datum), ca 600 m a.s.l., pitfall 5U emptied 28 March 2012, M. Driessen and N. Doran, QVMAG QVM:2018:23:0118.

Paratypes.

In QVMAG: 2 males, dissected and without gonopods (see Remarks), details as for holotype, QVM:23:54522.

Other material.

None.

Name.

For the type locality, Mt Weld.

Description.

In alcohol, specimens grey-brown with lighter annular band at rear of metazonite. Largest male (paratype) with 36+4 body rings, 1.9 mm midbody diameter. Head smooth, clypeus moderately setose. Ocellar area lenticular; ca 20 ocelli in 4 rows in largest male (paratype), dorsal> ventral 6,6,5,3. Antennae short, just reaching rear of ring 2 when extended dorsally; relative antennomere lengths (2=3=6)>(4=5); antennomere 6 widest; 4 apical cones. Gnathochilarium (Fig. 3A) with lateral edges of mentum slightly convex; mentum wider than combined lingual plates, anterior edge strongly concave, posteriorly with wide medial depression, the posterior lip of the depression sharply defined, broadly “U” -shaped; promentum triangular with base of triangle convex. Collum strongly convex, almost symmetrical around transverse axis, the corners bluntly acuminate. Ring 2 with ventrolateral margin slightly produced, rings 3 and 4 similarly produced but less so. Prozonites and metazonites (Fig. 3C) smooth, shiny; shallow waist with weakly defined suture line, most distinct dorsally; indistinct, fine horizontal striae in lower 1/3 of trunk rings, anteriorly bending upwards and extending anteriorly onto the prozonite, past an imaginary continuation of the suture. Limbus lamellar, undivided. Ozopore on ring 6 at ca 1/2 ring height, slightly higher on subsequent rings; ozopores small, round, located ca 1/3 the distance between suture and posterior metazonite margin. Telson with preanal ring smooth; posterior margin only slightly extended over anal valves medially, not forming distinct epiproct; hypoproct with gently convex dorsal margin. Midbody legs ca 2/3 ring diameter in length; relative podomere lengths (prefemur=femur=tarsus)>postfemur>tibia.; claw ca 1/2 as long as tarsus. No prefemoral tab on any legs.

Leg 1 (Fig. 3B) with coxa laterally produced, anteroposteriorly flattened, with a few setae on distal margin lateral to prefemur; prefemur reduced, with normally long setae; distal podomeres as in walking legs, with normally long setae; relative podomere lengths femur>tarsus>postfemur>tibia>>prefemur; claw ca 1/2 tarsus length. Leg 2 with penis forming a small plate at posterodistal end of elongated coxa.

Aperture (Fig. 3D) V-shaped (apex to rear), the margin thickened and slightly raised posteriorly. Gonopods (Figs 3D, 4) in situ forming small, compact complex strongly tilted posteriorly. Anterior gonopod coxa short, bulbous, cradling base of telopodite laterally; coxal process arising distomedially and extending as flattened tab curving posteriorly and partly sheltering telopodite medially. Telopodite (Fig. 4A, B) erect, taller than coxal process, broad basally and strongly tapered. the tip curving posteriorly; pseudoflagellum wide, branching off medially at ca 2/3 telopodite height, paralleling telopodite but not as high, broadly rounded at apex; posterior surface of telopodite with narrow, flattened ridge bearing a few setae, continuing distally on pseudoflagellum; prostatic groove running along posteromedial surface of telopodite base, curving anterodistally and following outer margin of telopodite, terminating at posteriorly directed telopodite tip.

Posterior gonopods (Fig. 4C) separate, less than 1/2 anterior gonopod height; cradled within coxal recess and partly sheltered distally by telopodite base; fingertip-shaped with flattened anteromedial surface distally and with 5 or 6 short apical setae.

Distribution.

Known only from the type locality (Fig. 5B).

Remarks.

When sorting spirostreptidan millipedes for an article on Tasmanian Iulomorphidae ( Mesibov 2017a), I set aside the three Mt Weld males as " Cambalidae ", because the males had a small, compact gonopod complex like the Tasmanian cambalids described above, and the legs lacked the prefemoral tabs found in Australian Iulomorphidae . The males also had apparently ambulatory first legs, which so far as I am aware have not been reported before in any iulomorphids. When preparing the current article, I removed the gonopods of two of these “cambalids” and cleared and imaged one of the undissected complexes. Unfortunately, I then lost the two gonopod complexes, leaving only one of the three males intact. Rings 7 and 8 of that male were removed for SEM imaging of the gonopod complex (Fig. 3D), but with only a very thin coat of metal applied. The rings were returned to alcohol and the gonopods dissected and illustrated here; this specimen has been designated the holotype.

I regret not having additional material of T. weldensis n. sp. for study and description, but the type locality is in Tasmania’s southern mountain district, which in 2019 remains a remote and little-sampled wilderness area. The three known specimens of T. weldensis n. sp. were in pitfall traps emptied on 28 March 2012 at 600 m on Mt Weld, during a biological monitoring study along an altitudinal transect. They were among ca 50 Amastigogonus verreauxii (Gervais, 1847) ( Iulomorphidae ) in pitfalls emptied on the same day at the same elevation ( A. verreauxii records in Mesibov (2006-2019)). The Mt Weld study generated its invertebrate samples in 2001-2002 and again in 2011-2012. I did not observe any other T. weldensis n. sp. specimens among the millipedes pitfall-trapped in the two sampling periods.