Asphalidesmus Silvestri, 1910

Mesibov, Robert, 2011, New species of Asphalidesmus Silvestri, 1910 from Australia (Diplopoda, Polydesmida, Dalodesmidea), ZooKeys 93, pp. 43-66 : 44-45

Asphalidesmus Silvestri, 1910

Asphalidesmus Silvestri 1910: 362. Attems 1914: 242, 1926: 153, 1931: 77, 1940: 205. Brölemann 1916: 547. Verhoeff 1932: 1587, 1936: 12. Jeekel 1971: 313, 1982: 12, 1984: 85, 1986: 46. Hoffman 1980: 150. Mesibov 2002: 532, 2009: 67. Golovatch 2003: 53. Golovatch et al. 2009: 3. Mesibov 2009: 67.

Type species:

Asphalidesmus leae Silvestri, 1910, by original designation.

Atopodesmus Chamberlin 1920: 153. Attems 1926: 134, 1940: 356. Verhoeff 1932: 1562. Jeekel 1971: 313, 1984: 85, 1986: 46. Hoffman 1980: 186. Mesibov 2002: 532 (synonymised). Golovatch et al. 2009: 3. Mesibov 2009: 67.

Type and only species:

Atopodesmus parvus Chamberlin, 1920, by original designation.

Other included species:

Asphalidesmus allynensis sp. n., Asphalidesmus bellendenkerensis sp. n., Asphalidesmus carbinensis sp. n., Asphalidesmus dorrigensis sp. n., Asphalidesmus golovatchi Mesibov, 2009, Asphalidesmus magnus sp. n., Asphalidesmus minor sp. n., Asphalidesmus otwayensis sp. n.

Diagnosis.

Small Dalodesmidea (4-6 mm long as adults) with head + 19 rings; adults yellow-brown and often encrusted with soil particles, juveniles pure white and not encrusted; collum, metatergites and preanal ring with 3-6 transverse rows of small, uniform tubercles, each bearing a single seta with a slightly flared tip; ring 2 paranotum expanded, extending forward to partly cover collum edge and backward to lie under anterior edge of ring 3 paranotum; all paranota lying low on sides, flexed downward and covering legs, with a few indistinct outer marginal lobes; pore formula normal, each ozopore opening on short, columnar structure arising just dorsal to the centre of the paranotum base; legs short, without sphaerotrichomes; gonopod aperture transversely ovoid, posterior rim slightly raised; gonocoxae entirely contained within aperture, small, distally tapered, lightly joined (not fused) medially; gonopod telopodites slender, parallel and close together, more or less straight, reaching bases of legpair 4 or 5 when retracted.

Remarks.

The genus description I offered nine years ago ( Mesibov 2002) still largely applies to Asphalidesmus golovatchi and the seven new species described below. The only significant changes are in number of transverse rows of tubercles on midbody tergites (varying from 3-6 in the genus, rather than 5-6) and in gonopod telopodite structure, which varies considerably from species to species. An Asphalidesmus adult can be easily recognised by its colour, by the size and position of the ring 2 paranota, and by the characteristic dorsal tuberculation, and can be distinguished using these features alone from similar-looking Australian Pyrgodesmidae and species of Agathodesmus Silvestri, 1910. However, whereas each of the latter taxa has a distinctive telopodite form as well as unique non-gonopodal features, Asphalidesmus telopodites are remarkably dissimilar (see descriptions and illustrations below).

In particular, there does not seem to be a common location on the telopodite for the opening of the prostatic groove. In the descriptions below I have avoided using the word ‘solenomere’ for the process with this opening, because doing so might suggest that those processes are homologous across the genus, and I doubt that they are. The prostatic groove opens on anterior and posterior branches in different Asphalidesmus species (with no sign of torsion in the course of the groove), on the tips of processes and subapically, and on the medial and lateral sides of the telopodite.

In his review of volvatory Polydesmida , Golovatch (2003) noted that the two Tasmanian Asphalidesmus species known at that time had only limited ability to coil (Fig. 1C), yet both had several anatomical features found in tightly-coiling ‘oniscoid’ polydesmidans in other families: short legs, downward-flexed paranota and a slight overlap of paranota on successive rings. Three of the new Asphalidesmus species are known to coil tightly (Fig. 1B), although in these species the paranota are short (on anterior-posterior axis) and do not overlap.