Equestrigonus tasmaniensis, Mesibov, Robert, 2017

Mesibov, Robert, 2017, Iulomorphid millipedes (Diplopoda, Spirostreptida, Iulomorphidae) of Tasmania, Australia, ZooKeys 652, pp. 1-36 : 25-26

Equestrigonus tasmaniensis sp. n. Figs 11, 12, 13

Holotype.

Male, Sideling Range, Tas, -41.2358 147.4131 ± 100 m [label "EQ 345 348" (= 55G 534500 5434800, AGD66)], 550 m a.s.l., 7 July 1993, T. Kingston, QVM 23:54173 (ex 23:11638).

Paratypes.

3 males, Sideling Range, Tas, -41.2303 147.4117 ± 100 m [label "EQ 344 354" (= 55G 534400 5435400, AGD66)], 550 m a.s.l., 15 June 1992, T. Kingston and R. D’Orazio, QVM 23:12719; 6 males, same details but 13 September 1993, T. Kingston et al., QVM 23:54057; 6 males, same locality but -41.2411 147.4106 ± 100 m [label "EQ 343 342" (= 55G 534300 5434200, AGD66)], 540 m a.s.l., 14 September 1993, T. Kingston et al., QVM 23:54094; 2 males, same locality but -41.2394 147.4083 ± 100 m [label "EQ 341 344" (= 55G 534100 5434400, AGD66)], 500 m a.s.l., 14 September 1993, T. Kingston et al., QVM 23:54095; 1 male, details as for holotype, 23:11637; 1 male, details as for holotype, QVM 23:11638.

Other material.

1013 males, 82 probable females and 12 possible juveniles from 68 unique localities in Tasmania; details in Suppl. material 1.

Description.

Living animals (Fig. 12A) have dark grey rings with annular pale band at rear of each metazonite; head, collum and last 1-2 rings before telson tinged with light brown; legs pale. With long storage in alcohol, ring colour fades to dark blue-grey, annular band darkens to light grey; often with brownish tinge on anterior rings; head and legs pale golden yellow (Fig. 11B).

Mature males (Fig. 11B) with (34+4) rings, 2.0 mm midbody diameter to (50+1) rings, 3.0 mm. Head (Fig. 12B) smooth, frons flattened, vertigial sulcus reaching to level of dorsalmost ocellar row. Posteroventral margin of cardo thickened and extended ventrally as large, rounded lobe (Fig. 12B; ce). Ocellar area narrow-triangular, triangle apex medial; ca 27 ocelli in 4 more or less regular horizontal rows, dorsal>ventral typically 9+8+6+4. Antennae short, barely reaching past posterior edge of collum when manipulated dorsally; relative antennomere lengths (2=3)>6>(4=5); antennomere 6 widest; 4 apical cones; socket ca 1 socket diameter from lateral margin of head capsule. Gnathochilarium (Fig. 12E) with lateral edges of mentum (Fig. 12E, me) slightly convex, mentum wider than combined lingual plates (Fig. 12E, lp); mentum-promentum (Fig. 12E, pm) junction nearly straight or slightly concave anteriorly; a prominent pit (Fig. 12E, sp) with small seta anteriorly on each gnathochilarial stipes (Fig. 12E, gs). Collum convex, laterally narrowing with rounded corner, margins straight. Ventral margin of ring 2 swollen posteriorly. Prozonites only slightly narrower than metazonites; prozonites with weakly defined annular striae anteriorly; suture weakly defined; fine longitudinal striae on lower half of metazonite, anterior end of each stria bent obliquely upwards towards suture; prozonites and metazonites with surface otherwise smooth, free of setae. Ozopores small, beginning ring 6, opening just above 1/2 ring height at ca 1/3 the distance between suture and posterior metazonite margin. Limbus lamellar, undivided. Preanal ring smooth, epiproct broadly rounded, extend ing slightly over anal valves; hypoproct with margin slightly convex dorsally. Midbody legs short, ca 2/3 ring diameter when extended; relative podomere lengths (prefemur=femur)>tarsus>(postfemur=tibia), claw ca 1/2 tarsus length. Prefemur distally with ventral flattening and conical prefemoral pad ca 1/2 femur length on midbody legs; pads first appear on ring 5 legs, diminish in posterior 1/3 of body and are greatly reduced or absent on last few legpairs.

Legpair 1 (Fig. 12C, D) separate on coxosternite, each leg 1 composed of broad basal and leg-like distal portion. Basal portion here assumed to be prefemur; widest at base, tapering medially, extending anterolaterally at base as large lobe (Fig. 12D; all) with a few distal setae; prefemur marked with several quasi-annular chitinous ridges and anteriorly bearing small field of coarse setae (Fig. 12D; sf), with large subquadrate tab (Fig. 12D; at) extending anteriorly. Distal portion with 3 well-demarcated podomeres, here assumed to be femur, postfemur and fused tibia+tarsus; femur widest, the tibia+tarsus narrowest and longest and with faint annular subdivision; all 3 podomeres sparsely and shortly setose; no claw.

Leg 2 (Fig. 12C, F) incrassate with large claw, prefemur reduced, coxa expanded anteriorly and distally with thick, tab-like apex (Figs 12C, F; ct); penis (Fig. 12F; pe) arising basally on posterior coxal surface, barrel-shaped with a few long setae in distal, marginal crown.

Coxae not elongated on near-aperture legs. Rear portion of gonopod aperture flat, not raised behind gonopods.

Anterior gonopods (Figs 11A, 13A) with coxite process (Figs 11A, 13A; cx) tapering to blunt spine extending further distally than telopodite (Figs 11A, 13A; te), and with short, spine-like process (Fig. 13A; pr) arising on anterior surface at level of pseudoflagellum on telopodite and directed distally. Telopodite tapering strongly, apex spatulate with spreading, marginal crown of ca 15 long, well-spaced setae; pseudoflagellum (Figs 11A, 13A; ps) branching off at ca 3/4 telopodite height on anterior surface, tapering to blunt tip and curving medially to terminate proximal to telopodite apex.

Posterior gonopods (Fig. 13B) ca 1/2 length of anterior gonopods, tapering from base, apex truncate distolaterally with apical crown of long setae; lateral process arising at ca 1/2 gonopod height, terminating at same level as body of gonopod, tip slightly expanded and flattened with convex distal margin.

Mature females (specimens in QVM 23:54050 and 23:54467) a little larger than males with same ring number; cardo not extended ventrally as in male.

Distribution.

Wet eucalypt forest and cool temperate rainforest in northern Tasmania (Fig. 7D), from 50 m to at least 900 m elevation; not yet collected south of 41°30'S latitude. Wanders on the forest floor and climbs tree trunks at night; shelters during the day in and under rotting logs and in leaf litter.

Name.

For the occurrence of this species in Tasmania; adjective.

Remarks.

The distinctive tips of the anterior gonopods invariably protrude from the gonopod aperture (Fig. 11A), allowing males of Equestrigonus tasmaniensis gen. n., sp. n. to be recognised without dissection. Western Tasmanian males are generally a little larger in diameter than eastern males.