Paradiplogynium nahmani Seeman

Seeman, Owen D., 2007, A new species of Paradiplogynium (Acari: Diplogyniidae) from Titanolabis colossea (Dohrn) (Dermaptera: Anisolabididae), Australia’s largest earwig, Zootaxa 1386, pp. 31-38 : 32-37

Paradiplogynium nahmani Seeman , sp. n.

Material examined. Holotype female (QM S73814): AUSTRALIA, Qld, Lamington National Park, Duck Ck, 15 Nov 1996, O. Seeman coll. ex adult Titanolabis colossea ( Dermaptera : Anisolabididae ) from beneath bark of a large rotting log ( Fig. 1 ). Paratypes: two males (QM S73815), same data. Holotype and one paratype deposited in Queensland Museum, Brisbane, one paratype deposited in the Australian National Insect Collection, Canberra.

Description. FEMALE ( Figs 2 , 4, 6–9 ): Dorsal idiosoma 910 long, 660 wide. Podosoma with 20 pairs of setae (j1, j3–6, z1, z3–6, s2–6, r2–6) and one unpaired seta (j2); opisthosoma with 13 pairs of setae (J1–5, others tentatively designated as Z1, S1–3, S5, R1–3). Setae j1 53, barbed, setae S5, Z5, J5 postero­marginal, S5 at least 115, barbed, Z5 83, smooth. Other setae in series jJ, zZ and sS 17–30, rR series 25–33, all weakly barbed. Dorsal shield covered with fine reticulation. Sternal shield with anastomosing network of reticulation, concave posteriorly, 100 long in midline, 173 long from anterolateral to posterolateral corner, 235 wide at widest point; with 3 pairs of setae and 2 pairs of lyrifissures. Setae st1 33, st2 33, st3 23, smooth, st1 and st2 stout. Distance between setae st1–st1 108, st2–st2 100, st3–st3 adjacent, st1–st2 13, st1–st3 95. Setae st4 18, on free paired metasternal shields, which have their anterior edges beneath the posterior margin of the sternal shield. Tritosternum lost during dissection. Genital shields. Latigynial shields each 143 long, 88 wide, with 1 pair of pores and 1 pair of setae, anterior and medial margins (to mesogynial shield) thickened, anterior margin invaginated, shields covered with linear to anastomosing pattern of reticulation. Mesogynial shield rectangular, 55 long, 25 wide, overlapped by latigynial shields in anterolateral region. Vaginal sclerites present, meeting medially at a porose plate; bent in specimen. Ventral shield fused with exopodal shield and embracing a membranous anal region; reticulation linear­anastomosing; with 4 pairs of smooth setae 18–25 long, and 6 pairs of irregularly placed pores anterior of anus; 2 pairs of smooth setae 28–30 long, one pair of pores and a pair of lyrifissures laterad and posterior of anus. Anal plates surrounded by membranous region 113 long, 143 wide. Without an unpaired postanal seta. Marginal shield with 6–7 pairs of pores and 1 pair of setae; shields meeting behind ventral shield and posteriorly fused with dorsal shield. Gnathosoma with 4 pairs of weakly barbed setae, h1 40, h2 55, h3 35, palpcoxal seta 30. Corniculi horn­like, 53 long. Gnathotectum triangular, with ventro­median keel, mounted laterally so tip not discernable. Palps unspecialised, setal counts from trochanter 2­5­7­15 setae; tarsus unclear, with 15–16 setae, apotele 2­tined. Fixed digit of chelicerae with 9 teeth (anterior 2 tiny), minute pilus dentilis, cheliceral seta, and serrated process; moveable digit with 7 teeth (most anterior tiny) and 3 excrescences: one short and brush like, one with minute papillae and only slightly longer than cheliceral digits, the other extending 45 past tip of moveable digit and covered with numerous papillae.

Leg chaetotaxy: CxI 2 (av, pv), TrI 6 (ad1, pd1, pl1, av1, pv1, pv2), FeI 1­2/2;2/2­1 (ad1, ad2, pd1, pd3, al1, pl1, av2, av3, pv1, pv2), GeI 1­3/1;2/1­1 (ad1, ad2, ad3, pd1, pd3, al1, pl1, av1, pv1), TiI 2­3/2;2/2­2 (ad1, ad2, ad3, pd1, pd2, al1, al2, pl1, pl2, av1, av2, pv1, pv2); TaI with ca. 28 setae before tarsal tip; tip with 2 long setae and about 6 sensilla. CxII 2, TrII 5, FeII 2­2/1;2/2­1 (ad1, ad2, pd1, pd2, al1, al3, pl1, av1, pv1, pv3), GeII 1­3/1;2/1­1 (ad1, ad2, ad3, pd1, pd3, al1, pl1, av1, pv1), TiII 1­1/1;2/1­1 (ad1, pd1, pd2, al1, pl1, av1, pv1), TaII 4+15 (ad1, ad2, ad3, ad4, pd2, pd3, pd4, al1, al2, al3, al4, pl1, pl2, pl4, av1, av2, av3, pv1, pv2). CxIII 2, TrIII 5, FeIII 1­2/1;2/1­0 (ad1, ad2, pd1, pd2, al1, av1, pv1), GeIII 1­2/1;2/1­1 (ad1, ad2, pd1, pd2, al1, pl1, av1, pv1), TiIII 1­1/1;2/1­1 (ad1, pd1, pd2, al1, pl1, av1, pv1), TaIII 4+15 (same as TaII). CxIV 1, TrIV 5, FeIV 1­2/1;2/1­1 (ad1, ad2, pd1, pd2, al1, pl1, av1, pv1), GeIV 1­2/1;3/1­1 (ad1, ad3, pd1, pd2, pd3, al1, pl1, av1, pv1), TiIV 1­1/2;2/1­1 (ad1, pd1, pd2, al1, pl1, av1, av2, pv1), TaIV 4+(2)+15 (same as TaII­III but with av4 and pv4 on intercalary sclerite that is fused with tarsus).

MALE ( Figs 3 , 5 ): Dorsal idiosoma 850–860 long, 600–610 wide. Dorsal setae as in female, S5 198, barbed, and Z5 85–98, smooth. Holoventral shield with anastomosing network of reticulation. Setae st 1 15– 18, flanking tritosternum base, st2 and st3 33, stout, adjacent and on raised tubercles that also bear modified stp1. Setae st 4 20–23, well behind (130) st2 and st3. Setae st 5 18–20 long. Tritosternum bifurcating, laciniae barbed. Genital opening beneath anterior margin of holoventral shield. Holoventral shield fused with exopodal shield and embracing a membranous anal region; 4 pairs of setae and 3 pairs of irregularly placed pores between anterior margin of anal membrane and CxIV; 1 pair of pores and 1 pair of setae lateral to anal membrane; 1 pair of setae, lyrifissures and pores posterior of anal membrane. Anal membrane 103–108 long, 120– 125 wide. Marginal shield with about 10 pairs of pores and 1 pair of setae; shields meeting behind ventral shield and posteriorly fused with dorsal shield. Gnathosoma with 4 pairs of weakly barbed setae, h 1 25–30, h2 58–60, h 3 28–30, palpcoxal seta 30. Corniculi horn­like, 38–40 long. Gnathotectum with rounded tip. Chelicerae as in female, except the short brush­like and short papillate excrescences are absent; instead, the base of the chelicera has 3 small lobes and a larger (40–43 long) somewhat sclerotised blade­like excrescence. Legs same as female.

Etymology. This species is described to celebrate the birth of Archie Oliver Nahman.

Remarks. This species is considerably larger than P. panesthia (910 vs 696 long), has one seta on each latigynial shield (instead of two), only two pairs of long marginal setae (instead of several pairs), and lacks a fine line linking the membranous anal region with the ventral shield. The species also differs in host, but I regard this host association as tentative because only three specimens were collected from a single earwig. However, I have collected extensively from logs in Lamington National Park (e.g., Walter et al. 1998), including numerous cockroaches that have their own species of Paradiplogynium allied to P. panesthia ( Seeman 2002) , and I have not encountered this species elsewhere, thus strengthening the possibility that this mite is closely associated with Colossus Earwigs.

Figures

FIGURE 1. Titanolabis colossea (Dohrn), host specimen for Paradiplogynium nahmani sp. n. Host specimen length = 45 mm.

FIGURE 2. Sternal, genital and ventral shields of Paradiplogynium nahmani sp. n., female. Marginal shields are not shown.

FIGURE 3. Sternoventral shield of Paradiplogynium nahmani sp. n., male. Marginal shields are not shown.

FIGURES 4 – 6. Paradiplogynium nahmani sp. n. 4, female chelicera; 5, male chelicera; 6, female leg I.

FIGURES 7 – 9. Paradiplogynium nahmani sp. n., female. 7, leg II; 8, leg III; 9, leg IV. Arrows designate an alternative interpretation of tarsal setae applicable to tarsi II – IV.