Tainisopidae

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 : 4

Key to the species of Tainisopidae

This key is provisional because additional species have been discovered that belong to this genus (locations shown in Fig. 1 ; C. Francis personal communication). The two species of Tainisopus Wilson & Ponder, 1992 are included to allow identification for all described members of this family. Pygolabis species are conservative in their overall morphology, as indicated by Figures 2– 13 . Species identification must, therefore, involve fine details, particularly on the pleotelson, uropods and the appendix masculina of the male pleopod 2. Other characters, such as counts of setae on various limbs or relative lengths of limbs, may be useful when detailed morphometric patterns from specimens comprising a large series of each species are known. The variable pleotelson in P. humphreysi presents difficulties in an identification key; we have attempted, therefore, to choose additional features that, although microscopic, will facilitate reliable identification of adults of the various species. Figure 2 explains some of the morphological characters used in this key.

1. Pleotelson anterolateral margins (anterior to uropods) short, uropods inserting anteriorly, posterolateral margin (posterior to uropods) broadly rounded; uropodal rami both distally rounded, endopod straight­sided (not curved) ............................ 5 ( Tainisopus )

– Pleotelson anterolateral margins enlarged, uropods inserting near midpoint of lateral margins, posterolateral margins sinuate, apex projecting; uropodal exopod flattened and distally rounded,endopod curving mediallyand distally pointed, forming robust claw ................................................................................................................... 2 ( Pygolabis )

Figures

FIGURE 1. Distribution of Pygolabis species in the Pilbara and Gascoyne Regions of Western Australia (box in upper right inset shows approximate position within the continent).

FIGURE 2. Selected morphological features used in the key and in the descriptions. A – B, pleotelson lateral inflection points of posterior margin indicated by single arrows: A, closer to uropod insertions that to apex; B, midway between uropod insertions and apex. C, distal tip of the pleotelson showing indentation. D – E, uropods showing comparative lengths of exopod and endopod, and position of small tooth­like setae (curved line marked with “ ts ”): D, endopod length exceeding 1.5 exopod length, with more than 15 small tooth­like setae; E, endopod length less than 1.5 exopod length, with less than 15 small tooth­like setae. F – G, male pleopod 2 appendix masculina distal cup size (see also Fig. 4): F, distal cup narrow, width subequal or narrower than proximal groove width; G, distal cup broad, width greater than proximal groove width. Images (not to same scale) from Pygolabis eberhardi sp. nov. (A, D), P. weeliwolli sp. nov. (B, C, E, F) and P. gascoyne sp. nov. (G)

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.

FIGURE 5. P. eberhardi sp. nov. Holotype male (WAM C 34942), except sternites PN 7 – PLN 1 male (AM P 70408), with and without pleopod 1. Scale bar 1 mm.

FIGURE 6. P. eberhardi sp. nov. pereopods. Male (AM P 70408); female (WAM C 34944). Scale bar 1 mm.

FIGURE 7. P. eberhardi sp. nov. Pleopods in dorsal view. Male 1 (AM P 70408); male 2 (WAM C 34942); female (WAM C 34944). Scale bar 1 mm.

FIGURE 8. P. weeliwolli sp. nov. Holotype male (WAM C 34948). Dorsal view shown in two sections owing to curvature of body. Arrow indicating ventral side of the pleotelson terminal margin. Bold arrow showing indentation on tip of pleotelson. Scale bar 1 mm.

FIGURE 9. P. weeliwolli sp. nov. Holotype male (WAM C 34948); paratype male 2 (AM P 70413). Scale bar: pereopods, 1 mm; pleopods 0.5 mm.

FIGURE 10. P. paraburdoo sp. nov. Holotype male, (WAM C 34951). Bold arrow showing indentation on tip of pleotelson. Scale bar 1 mm.

FIGURE 11. P. paraburdoo sp. nov. Paratype male 2 (AM P 70416); holotype male (WAM C 34951). Scale bar 0.5 mm.

FIGURE 12. P. gascoyne sp. nov. Holotype male (WAM C 34953). Bold arrow showing indentation on tip of pleotelson. Scale bar 1 mm.

FIGURE 13. P. gascoyne sp. nov. Holotype male (WAM C 34953). Scale bar 0.5 mm.