Fedrizzia sellnicki Womersley

Seeman, Owen D., 2007, Revision of the Fedrizziidae (Acari: Mesostigmata: Fedrizzioidea), Zootaxa 1480, pp. 1-55 : 29-30

Fedrizzia sellnicki Womersley

Fedrizzia sellnicki Womersley, 1959: 18 .

Fedrizzia sp. cf. grossipes Canestrini ( Womersley, 1959: 16)

Type specimens. Holotype, F, AUSTRALIA, Queensland: Mt Lamington, 1946, M. Sellnick, ex passalid beetle (N1952295a-d). In SAMA. Paratype, Queensland: M, same data as holotype (N1952296a-c).

Other specimens. Queensland: 3 F, Mt Glorious, 6.ii.1951, E. H. Derrick, on passalid; 2 F, 2 M, Dalby, 28.ii.1925, H. Geary, on passalid (N1952297-N1952306). In SAMA. Queensland: 3 F, 3 M, Mt Glorious, 6.v.1995, O. Seeman ( S74048 -53); M, Mt Glorious, 8.xi.1995, O. Seeman (S74054); 2 F, M, LNP, Duck Ck, 20.iii.1995, D. E. Walter (S740555-57); M, LNP, Blue Pool, 25.ii.1996, O. Seeman ( S74058 ); F, M, Main Range National Park, 11.ii.1996, O. Seeman (S74059-60); M, F, Mt Glorious, 6 May 1995, O. Seeman (S74061-62); M, F, Paradise, BM, 13 Feb 1996, O. Seeman (S74063-64). All collected from M. quaestionis and deposited in QM.

Specimens identified as F. sp. cf. grossipes : AUSTRALIA, Queensland: 5 F, 8 M, Imbil, 11.ix.1946, F. J. Gay, from passalid beetles (N1952480a-c, N1952481a-e, N1952482-N1852497); 2 F, 2 M, Yarraman, 29.viii.1935, A. R. P., unknown host (N1952498-N1952499, N19524501-N1952502); M, Dalby, 25.xii.1952, H. Geary, ex Aulacocyclus sp. (N1952503). In SAMA. New South Wales: M, Tenterfield, 8.x.1956, G. F. Bornemissza, ex P. dilatatus (N1952500). In SAMA.

Diagnosis. Both sexes: idiosoma 1020 –1070 long, with 8–10 large pores; ventral and ventrianal shield with mesh-like pattern, marginal shield with mesh-line to lineate reticulation; anterolateral corner of ventrianal shield fused with ventral shield; exopodal patterning between CxII–III spotted; pedofossae III absent; CxIV-marginal suture absent; femur III and IV without lamellae, seta pv1 not significantly thickened; femur IV elongated; seta h1 unmodified. Female: setae st2-4 4–9 long; lyrifissure stp2 anterior of stp x; sternogynial shield with honeycomb-like reticulations, loosely flanked by a cluster of pores, and surrounded by a smooth area extends only 20–30 posterior of genital shield. Male: sternoventral shield with suture behind genital opening demarking anterior smooth and posterior reticulated areas; genital opening not flanked by pores; seta h3 positioned posterior of h2.

Remarks. The holotype is in very poor condition. The paratypes of F. s e l l n i c k i are in poor to good condition; the best female is N1952298, the best male is N1952303.

Fedrizzia sellnicki is remarkably similar to F. sp. cf. grossipes , described by Womersley (1959), and was separated by sternogynial shield length (141 in sp. cf. grossipes , 117 in F. sellnicki ), ventrianal shield size (400 x 140 in sp. cf. grossipes , 450 x 185 in F. s e l l n i c k i) and idiosoma dimensions (1160 x 870 in F. sp. cf. grossipes, 1195 x 928 in F. s e l l n i c k i). My collections of this species have a sternogynial shield of 128–133 long (thus intermediate), a ventrianal shield size of 490–550 wide and 150–168 long, and idiosoma dimensions of 1160–1260 long and 910–1010 wide.

Womersley (1959) found that the size of the idiosoma , ventrianal shield and the shape of the mite were all highly consistent and useful characters for distinguishing species of Fedrizziidae . This observation is partially true; the size of the idiosoma is a useful feature, it does seem somewhat consistent, but it does vary and ± 5% would be typical for a species. Ventrianal shield size also varies, but also suffers from being an ambiguous measurement in species of Fedrizzia (like F. s e l l n i c k i) that have the anterolateral corners of the ventrianal shield fused with the ventral shield. Unless measurements are exceptionally different, this character is of little use. Finally, the shape of F. sp. cf. grossipes and F. s e l l n i c k i is not different, although Womersley’s observation of species having certain shapes is true for some species. For example, N. vidua and N. tragardhi have similar idiosomal dimensions, but the former species looks round whereas the latter is elongated. Therefore, I have decided that the species described as F. sp. cf. grossipes is best considered as F. sellnicki .

The specimens of F. sp. cf. grossipes in Womersley’s collection contain two slides of “? Fedrizzia grossipes deutonymphs”. These specimens are Uropodidae . Most slides are ruined or in poor condition; the best slides are N1952499 (M) and N1952483 (F, squash mount). I have collected over 650 adult F. sellnicki from M. quaestionis and M. sp. nr australasicus , and just 9 specimens from P. dilatatus . Both occasions of F. sellnicki occurring on P. dilatatus were in logs it cohabited with M. quaestionis . Therefore, the occurrences of this mite species on P. dilatatus are unusual or misidentifications of host species.