Paredrodesmus taurulus, Mesibov, Robert, 2003

Mesibov, Robert, 2003, Two new and unusual genera of millipedes (Diplopoda: Polydesmida) from Tasmania, Australia, Zootaxa 368, pp. 1-32 : 9-11

Paredrodesmus taurulus n. sp.

Figs. 1 , 6 , 7 , map Fig. 12 B

Holotype: Male, Tarraleah , DP472167 (42°17’59”S, 146°21’33”E), 720m, 18.iv.1992, R. Mesibov, QVM 23:25483 .

Paratypes: 3 males, details as for holotype, AM KS86294 ; 7 males, details as for holotype, QVM 23:41104 ; 12 males, Stoodley Plantation , DQ492185 (41°22’59”S, 146°23’32”E), 180m, 19.vi.2003, R. Mesibov, QVM 23:25462 .

Other material examined: 171 males and 1 female (from pair in copula). See Appendix for details.

Diagnosis: Differs from other Paredrodesmus in the greatly swollen podomeres and large claw on leg 2, the median notch on the posterior margin of the gonopod aperture and 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 pale yellow with purple mottling on distal antennomeres and brown speckling near the posterior margin of metazonites and around ozopores. Antennal bases separated by ca. 1.25 times a base diameter, antennomere 6 a little wider than 5. Leg 2 with genital opening on a prominent mesal projection and with greatly swollen podomeres, a curved tarsus and an unusually large claw ( Fig. 6 A). Legpair 3 ( Fig. 6 D) separated by a prominent, densely setose sternal projection. Legpairs 6 and 7 with a wide gap between opposing coxae, legpairs 4 and 5 with a narrower gap containing small, paired brushes of short setae; flexed gonopods reach to legpair 5. Rear margin of gonopod aperture barely raised, with a shallow median notch ( Fig. 7 ).

Telopodites ( Fig. 7 ) pressed close together but not fused, the mesal surfaces flattened, outer surfaces rounded. Telopodite base small with a few short and long setae, tapering smoothly medially to form the distal portion of the telopodite, the latter of fairly uniform diameter but with a rounded posterior bulge at about 0.4 of its length, with a short seta in a deep socket just proximal to the bulge. The tip of the telopodite rounded, extending laterad and slightly proximad in a tapering process which curves distad near its tip, the latter minutely rugose on its anterior surface. Solenomerite a prominent, subcylindrical process with a somewhat flattened, minutely rugose tip, pointing caudad from a deep recess on the posterolateral surface of the telopodite just proximal to the tip. The prostatic groove runs along the mesal surface of the telopodite, crosses the posterior surface of the tip distal to the solenomerite recess and curves back to enter the recess on its far (lateral) side.

Distribution and habitat: In well­rotted litter, humus and richly organic soil over ca. 10 0 0 0 km 2 in northern and northwestern Tasmania from 60 m to at least 1100 m, mainly in wet eucalypt forest ( Fig. 12 B). A male Paredrodesmus from Flinders Island in eastern Bass Strait, northeast of the main island of Tasmania ( Fig. 12 B), is a typical P. taurulus , but a disjunction of this kind is highly unusual in the Tasmanian millipede fauna and the record needs to be confirmed. Overlaps in range with P. bicalcar , co­occurs with P. monticolus . P. taurulus is the most abundant Paredrodesmus in Tasmania, with local populations often averaging 50 individuals per square metre. This species is also common in exotic tree plantations ( Bonham et al. 2002 [as ‘genus C, sp. 1’]; Mesibov, unpublished data).

Etymology: Latin taurulus = diminutive of taurus, bull, noun in apposition, from the resemblance of the paired gonopod telopodites in situ to the head of a bull with widespreading horns.

Figures

FIGURE 1. General views of females of Procophorella innupta n. sp. (left) and Paredrodesmus sp., probably P. taurulus n. sp. (right). Both specimens are ca. 10 mm long.

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 7. SEM views of Paredrodesmus gonopods in situ. (Left) P. taurulus n. sp., QVM 23: 41132; anterior to right, scale bar = 0.45 mm. (Right) P. aceriodendron n. sp., QVM 23: 41165; anterior to left, scale bar = 0.5 mm, ‘ c’ = crimp.

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).