Pygolabis humphreysi Wilson

Keable, Stephen J. & Wilson, George D. F., 2006, New species of Pygolabis Wilson, 2003 (Isopoda, Tainisopidae, Crustacea) from Western Australia, Zootaxa 1116, pp. 1-27 : 7

Pygolabis humphreysi Wilson ( Figs 3 , 4 A–B)

Pygolabis humphreysi Wilson, 2003: 245 , figs 1–7.

Material examined. Western Australia: Pilbara Region: Newman Borefield: male, bore W157, 23°13.0'S 119°54.0'E, fld. no. BES 3534, 11 xi 1998 (S. Eberhard) ( WAM C34940); male (illustrated), body length 8.9 mm, bore W78, 23°19.75'S 119°51.25'E, fld. no. BES 4833 haul net, 23 vii 1997 (W.F. Humphreys, S.M. Eberhard) ( WAM C34941); male, bore W23­4 south west of ore body 23 Fortescue River catchment, 23°19.03'S 119°51.02'E, fld. no. PSS 002, 10 iv 2003 (J.S. Cocking, S.A. Halse) (AM P70401); 2 females, male, body length 8.8mm, bore W260 at Production Bore K31 Fortescue River catchment, 23°17.51'S 119°52.2'E, fld. no. PSS 003, 13 x 2004 (H.J. Barron, J.S. Cocking) (AM P70402); 2 males, 1 female, bore W28 Great Northern Highway near Newman Airport, 23°24.20'S 119°47.76'E, depth to water 5 m, depth to bottom 8 m, fld. no. PSS 005, 10 iv 2003 (J.S. Cocking, A.E. MacIntosh) (AM P70403, slide STY 002).

Diagnosis. Pleotelson. Distance between uropod insertions and apex subequal to half length of pleotelson, lateral inflection points of posterior margin midway between uropod insertions and apex (or closer to apex than to uropod insertions); apex posterior margin indentation absent. Pleopod 2 male endopod appendix masculina. Teeth on lateral margin barely projecting from lateral margin, separated by less than tooth width for more than half of lateral margin length, proximal teeth subequal to lateral teeth in middle of ridge, lateral margin forming smoothly rounded arc; distal tip with broad (width greater than proximal groove width) cup, medial distal margin rounded. Uropods. Protopod extending beyond pleotelson apex.

Remarks. Wilson (2003) mentioned that this species showed variation in the form of the pleotelson apical projection, with the projection length apparently correlated with body length–larger specimens had larger projections. In Figure 3 , we show a specimen with the short pleotelson projection. We have observed no consistent features that would suggest that this species might contain two distinct taxa.

Distribution. Newman Borefield and surroundings, 23°17–24'S 119°48–53'E, Pilbara Region, Western Australia.

Figures

FIGURE 3. Pygolabis humphreysi Wilson, 2003. Male (WAM C 34941). Scale bar 1 mm. Pleopod 2 endopod scale bar 0.5 mm.

FIGURE 4. Comparison of the appendix masculina (male pleopod 2 endopod, right side) of three species of Pygolabis: P. humphreysi (AM P 64993) A – B; P. eberhardi sp. nov. (AM P 70408) C – F; P. weeliwolli sp. nov. (AM P 70413) G – I. Light micrographs of parts (A, C, G) prior to SEM imaging (B, D – F, H – I). All are in ventral view, except B and I – dorsal view, and F – posterodistal view. Scale bar 100 microns.