Paredrodesmus bicalcar, Mesibov, Robert, 2003

Mesibov, Robert, 2003, Two new and unusual genera of millipedes (Diplopoda: Polydesmida) from Tasmania, Australia, Zootaxa 368, pp. 1-32 : 14-15

Paredrodesmus bicalcar n. sp.

Figs. 6 , 8 , 9 , map Fig. 12 C

Holotype: Male , Newall Creek, CP789311 (42°09’45”S, 145°32’02”E), 80m, 27.xii.1993, R. Mesibov, QVM 23 :41188.

Paratypes: Male , details as for holotype, AM KS86291 ; 3 males (1 dissected), Bracken Ridge , DN897308 (43°04’31”S, 146°52’24”E), 360m, 17.i.1995, R. Bashford, QVM 23 : 41198, pitfall 1–4a; 16 females, Little Rapid River , CQ547397 (41°10’51”S, 145°16’03”E), 400m, 6.x.1993, R. Mesibov, QVM 23 :41187.

Other material examined: 25 males, 28 females and 14 juveniles. See Appendix for details.

Diagnosis: Differs from other Paredrodesmus in having an epiproct divided into two large spurs, a long process on the leg 1 prefemur, setose sternal outgrowths between legpairs 3, 4 and 5, and in the unique form of the gonopod.

Description: As for the genus. Males 10–11 mm long, 0.8–0.9 mm in maximum vertical diameter. In alcohol, well­coloured adults are uniformly pale yellow apart from purple mottling on distal anntennomeres. Antennal bases separated by ca. 1.25 times a base diameter, antennomere 6 about 1 and a third times the width of 5 ( Fig. 6 B). Leg 1 with a spurlike prefemoral process extending distad and caudad ( Fig. 6 E); genital opening on leg 2 coxa on a prominent mesal projection ( Fig. 6 A); legpairs 3, 4 and 5 separated by a densely setose sternal projection ( Fig. 6 E), coxae of these 6 legs slightly produced distally and mesally; legpairs 6 and 7 with a wide gap between opposing coxae. Flexed gonopods reach to legpair 5. Epiproct divided into two large spurs ( Fig. 9 ). Gonopod aperture with rear margin raised in the middle. Telopodites ( Fig. 8 ) not closely pressed together. Telopodite base small with a few very long setae; the distal portion of the telopodite arising medially, curving smoothly caudad and expanding into a broad tip with a slightly rounded distal surface. Prostatic groove running along the mesal surface of the telopodite before entering the solenomerite (‘s’ in Fig. 8 ). Solenomerite a small, blunt process which arises from the anteromesal corner of the telopodite tip and curves first cephalad, then proximad, then distad. The lateral edge of the telopodite tip bears a radiating fan of ca. 40 variably long, peglike structures, and two long setae arise on the anterior surface of the telopodite just proximad to the broad tip.

Distribution and habitat: In well­rotted litter, humus and richly organic soil over ca. 20 0 0 0 km 2 in western Tasmania from near sea level to ca. 1000 m, mainly in wet eucalypt forest and Nothofagus rainforest ( Fig. 12 C). Overlaps in range with P. monticolus , P. t a u ­ rulus and possibly with P. p u r p u re u s, co­occurs with P. australis . Over most of its range this species appears to be uncommon.

Etymology: Latin bi, two, + calcar, spur, noun in apposition, referring to the twospurred epiproct in this species.

Remarks: The epiproct spurs are also present in stadium V males, the youngest juveniles examined.

Figures

FIGURE 6. Antennae and legs of Paredrodesmus spp. males. All drawings to same scale, apical cones and setation not shown. (A) Leg 2 of (left to right) P. aceriodendron n. sp., QVM 23: 41165, P. australis n. sp., QVM 23: 41167, P. b i c a l c a r n. sp., QVM 23: 41178, P. monticolus n. sp., QVM 23: 41155, P. p u r p u re u s n. sp., QVM 23: 41524 and P. taurulus n. sp., QVM 23: 41132; (B) antennae of (left) P. b i c a l c a r n. sp., QVM 23: 41178 and (right) P. aceriodendron n. sp., QVM 23: 41165; (C) leg 9 of P. purpureus n. sp., QVM 23: 41524; (D) leg 3 and sternal projection of P. taurulus n. sp., QVM 23: 41132; (E) leg 1 (left, posterior view) and leg 3 and sternal projection (right) of P. b i c a l ­ car n. sp., QVM 23: 41178.

FIGURE 8. SEM views of Paredrodesmus gonopods in situ. (Left) P. australis n. sp., QVM 23: 41169; anterior to right, scale bar = 0.5 mm. (Right) P. bicalcar n. sp., QVM 23: 41178; anterior to right, scale bar = 0.35 mm, ‘ s’ = solenomerite.

FIGURE 9. Dorsal SEM views of epiprocts of (left) male Paredrodesmus taurulus n. sp., QVM 23: 41140, and (right) male P. b i c a l c a r n. sp., QVM 23: 41197. Scale bar in both cases = 0.5 mm.

FIGURE 12. Distributions in Tasmania of Paredrodesmus spp. (A) P. aceriodendron n. sp. (large squares) and unidentified Paredrodesmus females and juveniles (small squares); (B) P. taurulus n. sp. (squares) and P. australis n. sp. (crosses); (C) P. b i c a l c a r n. sp. (squares); (D) P. monticolus n. sp. (crosses) and P. purpureus n. sp. (squares).