Castriidinychus robynae, Dylewska & Błoszyk & Halliday, 2010

Dylewska, M., Błoszyk, J. & Halliday, R. B., 2010, Three new species of mites in the genus Castriidinychus Hirschmann from Tasmania (Acari: Uropodidae), Zootaxa 2546 (1), pp. 1-30 : 20-27

Castriidinychus robynae sp. nov.

Types. Tasmania. Holotype. Female. Big Sassy Creek , 21 km NNW of Little Swanport, site 2, litter, 42°09'S 147°55'E, 17.v.89, P. Greenslade coll., TAS-195 (in ANIC) . Paratypes. Tasmania. 2 males, 1 DN, same data as holotype; 1 female, Pirates Road, Tasman Peninsula, 2.5 km SW of Eaglehawk Neck, south track, Nothofagus cunninghamii , moss on fallen log, 43°03'S 147°55'E, 21.iii.89, J. Diggle coll., TAS-045; 1 female, Pirates Road, Tasman Peninsula, 2.5 km SW of Eaglehawk Neck, south track, Nothofagus cunninghamii , litter, 43°03'S 147°55'E, 21.iii.89, P. Greenslade and J. Diggle coll., TAS-052; 1 female, 1 male, Old Farm Road, Mount Wellington , Eucalyptus forest, litter, 42°54'S 147°14'E, 20.vi.89, P. Greenslade coll., TAS-183; 1 male, Big Sassy Creek , 21 km NNW of Little Swanport, site 1, litter, 42°09'S 147°55'E, 12.v.89, P. Greenslade coll., TAS-193 (in AMU and ANIC) .

Female. Dorsal idiosoma ( Fig. 20 ). Length 461–530 µm (mean 503 µm), width 323–380 µm (mean 346 µm) (n = 4). Dorsal shield oval, with very strong ornamentation of circular and irregular pits. Dorsal setae numerous and massive, smooth, 49–55 µm long. Marginal shield narrow, clearly demarcated from dorsal shield, setae j1 and three pairs of anterior marginal setae z1, r2, r3 long (44–62 µm), massive, serrated.

Ventral idiosoma ( Fig. 5C , 21 ). Tritosternum with narrow base and four forked laciniae. Sternal shield with very strong lateral ornamentation of circular pits. Sternal/genital region with four pairs of short, simple sternal setae, one near camerostome and three lateral of epigynum, st4 located at level between coxae III and IV. Epigynial shield tongue-shaped, articulated at level of coxae IV, ornamented with circular pits, length 112– 122 µm (mean 116 µm), width 73–80 µm (mean 76 µm) (n = 4). Opisthosoma with strong punctate ornamentation and five pairs of ventri-anal setae, postero-lateral pair longest (32 µm). Anal opening small, oval, flanked by two pairs of adanal setae, Ad1 shorter than Ad2, post-anal seta Pa longer. Submarginal ventral setae long and smooth. Peritreme with characteristic U-shaped bend, stigmata at anterior level of coxae II.

Gnathosoma ( Fig. 8E ). Hypostomal setae h1 long (27 µm), massive, smooth, h2 shorter than h1 (22 µm), serrated, h3 longer than h2 (31 µm), medially serrated, h4 shortest (13 µm), massive, serrated. Ventral setae on palp trochanter long, serrated.

Male. Dorsal idiosoma. Length 480–530 µm (mean 515 µm), width 310–390 µm (mean 388 µm) (n = 5). Structure and chaetotaxy as for female.

Ventral idiosoma ( Fig. 22 ). Intercoxal region strongly ornamented, with five pairs of very short simple setae. Setae st4 and st5 situated lateral to genital operculum. Genital operculum oval, smooth (46–58 x 27–41 µm), without setae. Chaetotaxy and sculpture of opisthosoma as in Fig. 22 .

Gnathosoma . Structure and chaetotaxy as for female.

Deutonymph. Dorsal idiosoma ( Fig. 23A ). Length 439 µm, width 288 µm (n = 1). Dorsal shield with characteristic ornamentation of large irregular pits and long, massive, simple setae; marginal shield wide.

Ventral idiosoma ( Fig. 23B ). Sternal shield elongate, narrowed between coxae IV; ornamented with large irregular pits, with five pairs of simple sternal setae and one pair of lyrifissures. Peritrematal, metapodal and pericoxal shields fused. Ventri-anal shield trapezoidal, lightly ornamented, with four pairs of ventral setae, two pairs of adanal setae, Ad2 longer than Ad1, and unpaired post-anal seta Pa. Opisthosomal integument with one pair of long smooth setae inserted on small platelets lateral to ventri-anal shield. Anal opening small and oval. Peritreme longer and less convoluted than in adult.

Etymology. This species is named in honour of Dr. Robyn Coy, who collected many of the specimens used in this study.

Notes. Castriidinychus robynae has been found at only three localities in southeastern Tasmania (Fig. 24). The vegetation in this area is mainly Eucalyptus forest, with small remnants of Sassafras ( Atherosperma moschatum ) and Nothofagus . It occurred in leaf litter under Sassafras, in moss and litter under Nothofagus , and in litter under Eucalyptus .

FIGURE 24. Distribution of Castriidinychus spp. in Tasmania. = C. tasmanicus ; ● = C. longisetosus ; = C. robynae .

Figures

FIGURE 5. Castriidinychus spp., females, intercoxal area and genital shield. A, C. tasmanicus; B, C. longisetosus; C, C. robynae. Scale bar 100 µm.

FIGURE 8. Castriidinychus spp., hypostome. A. C. tasmanicus female; B. C. tasmanicus male; D, C. longisetosus female; D, C. longisetosus male; E, C. robynae female. Scale bar 50 µm.

FIGURE 20. Castriidinychus robynae, female, dorsal idiosoma. Scale bar 100 µm.

FIGURE 21. Castriidinychus robynae, female, ventral idiosoma. Scale bar 100 µm.

FIGURE 22. Castriidinychus robynae, male, ventral idiosoma. Scale bar 100 µm.

FIGURE 23. Castriidinychus robynae, deutonymph. A, dorsal idiosoma; B, ventral idiosoma. Scale bar 100 µm.