Willungella rufusanus Seeman & Palmer

Seeman, Owen D. & Palmer, Christopher M., 2011, Parasitism of Apteropanorpa tasmanica Carpenter (Mecoptera: Apteropanorpidae) by larval Leptus agrotis Southcott (Acari: Erythraeidae) and Willungella rufusanus sp. nov. (Acari: Microtrombidiidae), Zootaxa 2925, pp. 19-32 : 23-25

Willungella rufusanus Seeman & Palmer sp. nov. ( Figs 1–6; Table 3)

Material examined

Holotype. Larva, AUSTRALIA (Tasmania), Mt Rufus, 23 April 2002, C.M. Palmer, ex Apteropanorpa tasmanica . Holotype deposited in TMAG.

Paratypes. AUSTRALIA (Tasmania): 15 larvae, same data as holotype. Two paratypes deposited in TMAG. Thirteen paratypes deposited in QM.

Other material examined. 6 larvae, Mt King William I, 24 April 2002, C.M. Palmer, ex Apteropanorpa tasmanica . Deposited in QM.

Differential Diagnosis

With characters of the genus, but femur I–III has 6, 6, 4 setae, respectively (compared with 6, 5, 4 in other species), and genu I–III has 3, 2, 2 solenidia, respectively (compared with 2, 1, 1 solenidia).

Description

Larva. Slightly to partially fed specimens flattened on slides. Measurements in Table 3. Idiosoma 430–544 long, 265–349 wide. Stolascutum punctate, concave at level of eyes, bearing three pairs of setae (AM, AL, PL) and a pair of sensilla (S). Setae AM and AL smooth, PL barbed; seta AL closer to PL than to AM. Eyes, anterior largest than posterior, on common sclerite.

Gnathosoma . Capitulum 97–104 long, subcapitular setae barbed, 15 long, protorostral setae smooth, 9 long. Stephanostome with external cuticular sheath weakly annulate, internal sheath horse-shoe shaped, open dorsally, smooth. Palp trochanter reduced, palp femur and genu each with small dorsal seta. Palp tibia with 2 setae, 1 of these at base of odontus, odontus 9–11 long and trifurcate. Palp tarsus with 6 setae, solenidium, and eupathidium. Cheliceral blade sickle-shaped and with two minute subapical teeth.

TABLE 3. Measurements (ranges, μm) for Willungella rufusanus sp. nov. larvae collected from Apteropanorpa tasmanica (n = 22).

Code Range in µm Code Range in µm Notes: Set of standard measurements and indices follows Southcott (1961).

Hysterosoma with barbed setae c1–3, d1–3, e1–3, f1–2, and ps1–3, and smooth setae h1–2; some specimens with extra seta in row d (d x in Figure 1). Setae c1 on punctate scutellum, setae c2 on separate scutella, setae d1 on separate scutella, remaining hysterosomal setae on small sclerites except h2. Seta h2 96–104 µm long. Posterior dorsal scutum smooth, 72–81 long, 190–195 wide. Anus 32–35 long.

Coxal setae: 1a smooth or with small fork, 43–46 long; 1b forked, 39–49 long; 2b forked, 45–47 long; 3a barbed, 35–38 long, on small platelets; 3b barbed, 39–44 long. Coxal plates punctate. Claparade’s organ 18–24 wide.

Legs. Segmentation 6-6-6. Setal counts (trochanter to tarsus): Leg I 1, 6, 4, 6, 18; Leg II 1, 6, 2, 5, 14; Leg III 1, 4, 2, 5, 12. Modified leg setae: GeI, microseta к and 3 solenidia σ; TiI, microseta к and 2 solenidia φ; TaI, solenidia ω, famulus ε, and eupathidia ξ1 (ξ2 absent); GeII, microseta к and 2 solenidia σ; TiII, microseta к + 2 solenidia φ; TaII, solenidia ω and famulus ε; GeIII, 2 solenidia σ. Leg I–II pretarsus comprising single trifurcate claw, empodium and apical eupathidium. Leg III truncate distally, with long anterior claw, apical stout claw, empodium, lophotrix (with 7 branches, 1 with setules) and barbed scopa.

Etymology

The specific epithet refers to the type locality.

Remarks

Although leg morphology is illustrated in detail, Southcott (1994) did not use leg setal characters for diagnoses in his major revision of the Microtrombidiinae . However, W. rufusanus has additional solenidia on genu I–II, and an extra seta on femur I, but still belongs in Willungella as defined by Southcott (1994).

Leg chaetotaxy is an essential component of any acarine systematic work that deals with higher classification, and the Microtrombidiidae is no exception. However, W. rufusanus is very similar to other Willungella species except for leg chaetotaxy, supporting Southcott’s reluctance to use leg chaetotaxy to define genera. Therefore, uncertainty over the usefulness of leg chaetotaxy, combined with the inability to correlate most larval and post-larval taxonomy, means an informative, phylogeny-based classification of the Microtrombidiidae is untenable at present.