Spirostreptus unciger ( Attems 1928 )

Mwabvu, Tarombera, Hamer, Michelle, Slotow, Robert & Barraclough, David, 2009, A revision of the taxonomy and distribution of Spirostreptus Brandt 1833 (Diplopoda, Spirostreptida, Spirostreptidae) with descriptions of a new species and a new genus of spirostreptid millipede, Zootaxa 2211, pp. 36-56 : 46-48

Spirostreptus unciger ( Attems 1928)

Figs 5 , 7 d

Triaenostreptus unciger Attems 1928 , p. 365, figs 318–320; Hoffman 1971; Krabbe 1982; Hamer 1998 Spirostreptus unciger: Hoffman 2008

Type material (not examined): SOUTH AFRICA: North West Province: Vryburg ( SAM).

Additional material examined: SOUTH AFRICA: Gauteng Province: 1 3, Pretoria [25 0 44'S, 28 0 11'E], x.1961, H. Fiedler ( NMSA 8896); 1 3, Pretoria [25 0 44'S, 28 0 11'E], 2004, ( NMSA 21939). Mpumalanga Province: 1 3, 1 Ƥ, Barberton, Mpumalanga [25 0 47'S, 31 0 03'E], xii.1909, Miss de Beer ( NMSA 18990). North West Province: 2 3, Barakolalo [25 0 16'S, 25 0 54'E], 14.i.2000, M. Hamer & R. Slotow ( NMSA 21975). Unknown locality: 1 3, iv.1966, G. Lombard ( NMSA 9609).

Diagnosis: Lateral lobe very wide proximally, distal part lying tightly against lateral edge of apical proplica ( Fig. 5 a); telopodite with distal side branch ( Fig. 5 c).

Description: Size: Body length 230–250 mm; minimum and maximum body width 5–8 mm and 11–15 mm; antenna length 12–13 mm.

Number of body rings: 67–73.

Colour: Body black or brownish; legs brown; antennae black or brown.

Collum: Anterior produced laterally into a narrow, rounded lobe, with 3 complete and 1–2 incomplete folds ( Fig. 5 e)

Pre-femoral process of 1st pair of male legs: Proximally U-shaped with short, apical nipple slightly deflected laterally ( Fig. 5 d).

Gonopod: ( Figs 5 a, 5b) 7–8 mm long. Sternite apex extends distally to level of paracoxite apex.

Proplica tapering apically, wider at the level of telopodite spiral. Proplica not overlapping the distal lobe, resulting in much of proximal lateral lobe being visible orally; lateral edge of proximal half of proplica raised more sharply than medial edge.

Distally, metaplica with a rounded hump and nipple-shaped apical extension proximal to distal lobe apex; metaplica width approximately constant along the length except at the level of lateral lobe, a deep depression present at the level of lateral lobe.

Free lateral lobe short and finger-like distally. Proximally lateral lobe broad and vertical. Lateral lobe lying tightly against proplica, does not extend beyond lateral edges of proplica or distal lobe ( Fig. 5 a). Distally lateral lobe widely separated from distal lobe.

Telocoxites parallel, slightly wider apart distal to sternite apex, medial edge straight, distal lobe not extending beyond lateral edge of proplica apex.

Post knee telopodite with a side branch distal to coil ( Fig. 5 c); antetorsal process of telopodite straight, extending past the origin of side branch ( Fig. 7 d).

Distribution: Known only from north-western and north-eastern South Africa

Remarks: The broad and vertical proximal part of the lateral lobe and the side branch on the telopodite distinguish unciger from congeners ( Figs 5 c, 7d). The distal lobes of the gonopods are as in congeners, however, the shape and surface texture suggest closer affinities with heros , batokensis and kruegeri . The position of the lateral lobe in relation to the proplica and distal lobe, and the wide separation of the apical proplica from the distal lobe are unique to unciger .

The type material of S. unciger is supposed to be in the SAM but is missing from this collection and from other institutions in southern African.

Figures

FIGURE 5. Spirostreptus unciger (NMSA 8896). a, oral view of gonopods; b, aboral view of gonopods; c, telopodite; d, oral view of prefemoral lobe of first pair of male legs; e, lateral view of collum. Abbreviations: p, proplica; m, metaplica; llb, lateral lobe; mn, metaplica nipple; dl, distal lobe; d, depression; tp, telopodite; tpb, telopodite branch; at, antetorsal process; pc, paracoxite; st, sternite; cf, collum fold; al, anterior lobe; pfl, prefemoral lobe.

FIGURE 7. Shape of antetorsal process of the telopodites of Spirostreptus species. a, S. heros; b, S. kruegeri; c, S. sebae; d, S. unciger; e, S. batokensis; f, S. tripartitus. Abbreviations: tp, telopodite; tk, telopodite knee; at, antetorsal process.