Nidilaelaps holdsworthi, Shaw, Matthew D., 2012

Shaw, Matthew D., 2012, Re-evaluation of Pseudoparasitus (Gymnolaelaps) annectans (Womersley): a new genus and two new species (Acari: Mesostigmata: Laelapidae), Zootaxa 3453, pp. 25-42 : 32-36

Nidilaelaps holdsworthi sp. nov.

( Figs 9–16 )

Specimens examined. Tasmania. Holotype female, Melaleuca, 43 25’11” S 146 09’44”E, 16 Jul 1999, M. Holdsworth coll., ex nest of Neophema chrysogaster Orange-bellied Parrot, in nestbox, MP1, NEST 320 (on left hand side of slide, circled), to be deposited in Tasmanian Museum & Art Gallery, Hobart; 1 paratype female QM S 90159 , Wilsons, nr Melaleuca, 43º 25’11” S 146º 09’44”E, 17 Jul 1999, M. Holdsworth coll., ex nestbox occupied by Neophema chrysogaster in Jan 1999, Rallinga 2, NEST 262; 1 paratype female, 5 paratype males QM S 90160 - 5, Melaleuca, 43º 25’11” S 146º 09’44”E, 17 Jul 1999, M. Holdsworth coll., ex nestbox occupied by Neophema chrysogaster in Jan 1999, NEST 263; 1 paratype female QM S 90166 , Melaleuca, 43º 25’11” S 146º 09’44”E, 3 Sep 2002, M. Holdsworth coll., occupied by Petrochelidon nigricans Tree martin , used by Neophema chrysogaster at other times, RS2, NEST 497; 11 females, 21 males, Melaleuca, Tasmania, 43º 25’11” S 146º 09’44”E, 17 Jul 1999, M. Holdsworth coll., ex nestbox occupied by Neophema chrysogaster in Jan 1999, NEST 263; 2 females, 3 males, same data as NEST 263 above, Lag 3, NEST 264; 5 females, 1 male, Melaleuca, Tasmania, 43º 25’11” S 146 º 09’44”E, 3 Sep 2002, M. Holdsworth coll., ex nestbox occupied by Petrochelidon nigricans Tree Martin , used by Neophema chrysogaster at other times, RS2, NEST 497; 3 females, Melaleuca, Tasmania, 43º 25’11”S 146º 09’44”E, 4 Sep 2002, M. Holdsworth coll., ex nestbox occupied by Cecropis nigricans , used by Neophema chrysogaster at other times, NEST 499.

South Australia. 2 females, QM S 90167 , Stoke's Bay, Kangaroo Is, 35º 37’S 137º 12’E, South Australia, 18 Nov 1998, Bill Prime coll., tree hollow nest of Calyptorhynchus lathami halmaturinus Glossy Black Cockatoo , active 5 months prior to collection, NEST 44-KKO;

Western Australia. 1 female, QM S 90168 , 16 km SW of Moora, 30º 40’S 115º 50’ E, 27 Nov 1998, P. Mawson, CALM, coll., ex active tree hollow nest of Calyptorhynchus latirostris Carnaby’s Black Cockatoo, NEST 45.

Description of females (n=10): Dorsum: Dorsal shield 645 (500–665) x 390 (325–445). Dorsal shield usually covers entire dorsum, some compressed specimens have 20 μm of unarmed cuticle bordering shield. Shield bears 39 pairs setae plus 1–3 supernumerary Jx setae at level of J4 ( Fig. 9 ). Seta j1 (23–25). Marginal and anterior podonotal setae moderately long, j2 40(37–50), r3 48(35–48), S1 57(45–58), S5 51(42–57), Z5 57(40–57), J5 46(38–50);central setae shorter, j5 44 (34–44), j6 44(34–39), z5 (32–40). All setae smooth except Z5 often with one to two barbs.

Gnathosoma: Movable digit 54 (45–60) with two teeth. Fixed digit with strongly divided apex and one strong additional tooth, distal of pilus dentilis ( Fig.11 ). This tooth opposes the distalmost of the movable digit teeth. Internal malae with weak lateral arms that fall short of corniculi tips ( Fig. 12 ). Cheliceral segment II 147 (120–147) long, cheliceral segment I 51 (44–60) long. Strong corniculi, 30 (21–32) long. h1 34 (34–41), h2 18 (14–20), h3 57 (49–58), capitular seta 38 (33–41). Deutosternal groove parallel-sided with six deutosternal rows of ca. 5 denticles each. Epistome a simple lobe ( Fig. 10 ).

Venter: Tritosternal base 32 (18–32) long to suture. Laciniae fork 17 (10–18) above suture. Free portion of laciniae 88 (70–88) long. Anterior edge of sternal shield is subcuticular, obscure. Cornua are narrow sclerites that arch over coxa II. Sternal shield 120 (107–131) deep by 128 (103–134) wide. Shield mostly smooth, anterior and lateral margins with some striae. St1 immediately external to central puncta of first lyrifissure. Sternal shield setae 1–3: 49 (40–54), 56 (46–57), 55 (44–58). Posterior margin of sternal shield with mild medial point. Genito-ventral shield ( Fig. 13 ) bearing only st5 and rarely Zv1 (e.g. RHS of paratypes QMS 90159, 90160). Shield 198 (160–200) long and 110 (91–123) wide at level of st5. Maximum width ca. 170 between Zv1 and Jv1. Zone of longitudinal striae represented as a fine margin of genito-ventral shield extending posteriorly beyond Zv1 as far as ca. Jv1. Transverse striae in 6–7 broad, serially-regular rows, with 5–6 striae at or below level of Zv1. Genito-ventral shield almost reaches anal shield [if the soft cuticle between these shields is folded during specimen preparation the shields may be seen to abut or overlap (e.g. Fig. 13 )]. Endopodal plate narrow and not capturing st4. Principal metapodal platelet 38 (30–40) long and 7 (6–11) wide. Secondary (inner) metapodal platelet 14 (8–18) long x 4 (2–5) wide. Paragenital platelets absent. Peritrematal shield separate from exopodal IV. Poststigmatal plate bearing usual 3 pore-like structures, posterior pore-like structure borne on plate margin. R series appear holotrichous, with R1–3 present anterior of pore Rp. Baseplates surrounding alveoli of opisthogastric setae expanded posteriorly for the same or less than diameter of setal insertions. Anal shield 84 (55–77) long by 87 (72–91) wide at cribral pores. Three regularly arranged rows cribral spicules present. Paranal setae 30 (26–32); postanal 50 (36–50).

Legs: Most setae simple and acicular except genu and femur II have av seta slightly thickened relative to other ventral setae (2–3 μm at base). Tibia II with av1 also thickened but only very slightly more than other ventral setae on distal leg segments such as tibia II pv1. Leg segment lengths shown in Table 3. Pretarsal opercula bear 6–7 tines.

I II III IV

Femur 96 (82–103) 80 (47–80) 80 (51–87) 109 (81–118) Genu 84 (63–87) 66 (55–76) 53 (39–56) 75 (56–80) Tibia 88 (73–91) 64 (53–66) 52 (40–57) 83 (64–87) Tarsus 142 (115–143) 111 (85–114) 118 (88–122) 160 (128–171) Description of male (n=10): As for female, except where noted.

Dorsum: Dorsal shield 385–440 x 240–300. 2–4 supernumerary Jx setae at ca. level of J4. Seta j1 setiform (16–27). Anterior podonotal, marginal and terminal setae longer, j2 (25–33), r3 (25–40), S1 (32–44), S5 (33–39). Central setae shorter, j6 (20–35), z5 (26–35).

Gnathosoma: Corniculi 18–22, h 1 25–29, h 2 13–16, h3 32–39, capitular seta 24–31. Deutosternal groove with 6 denticulate rows, flanked by 4 transverse lines. Movable digit 31–44 with single tooth. Fixed digit with divided tip only, i.e. with a single cusp. Spermadactyl free for most of its length, tapering gradually to a terminal bore of ca 2μm, tip with sharp triangular point ( Fig. 15 ). Second cheliceral segment 88–102, first cheliceral segment 32–45. Venter: Male opening oval-shaped, wider than deep 19–28 x 10 –13. Opening positioned anteriorly with posterior edge ca. level with st1 ( Fig. 14 ).

Legs: Femur av1 stout (ca. 12 x 4) with blunt rounded tip ( Fig. 16 ). Leg segment lengths are shown in Table 4.

I II III IV

Femur 63–78 40–70 40–60 59–82 Genu 50–67 45–60 30–43 45–62 Tibia 57–76 44–60 34–46 49–65 Tarsus 96–113 70–80 72–90 105–132

Remarks. Aside from Tasmanian collections, Nidilaelaps holdsworthi sp. nov. was recovered from natural nest hollows used by cockatoos in SW Western Australia and on Kangaroo Island, South Australia. On Kangaroo Island, of 12 Calyptorhynchus lathami halmaturinus cavity nests sampled, N. holdsworthi was found in only 2 nests, both of which were natural tree hollows. Most N. holdsworthi specimens recovered in this study were from nestbox collections in Tasmania. Of 40 such nestboxes sampled, N. holdsworthi sp. nov. was found in 7 that were used by Orange-bellied Parrots [ Neophema chrysogaster (Latham) ], or by Tree Martins [ Petrochelidon nigricans (Vieillot) ], or both of these species. It was the most common mesostigmatan mites in these nestboxes.

The chelicerae and corniculi of N. holdsworthi are more compact than N. annectans and with a relatively reduced dentition. However such robust chelicerae suggests that N. holdsworthi is probably a predator. Putatively related taxa that are known bloodfeeders e.g. Androlaelaps penelope (Domrow) have more slender chelicerae. Supporting this hypothesis, its presence in nestboxes that were without nesting birds for five months or more prior to collection suggests that it is not haematophagous, at least not obligately so. Rather, I suggest that N. holdsworthi may prey upon small arthropods, including haematophagous mites, that also occur in these nests. In the Tasmanian samples, N. holdsworthi co-occurred with Pellonyssus reedi (Zumpt & Patterson) and Dermanyssus hirundinus (Hermann) . In South Australia, N. holdsworthi co-occurred with Ornithonyssus bursa (Berlese) . In Western Australia, N. holdsworthi occurred in the same type of tree hollow nests as O. bursa , although it was not detected in the same individual nests. It is noteworthy that all three of these haematophagous mite species are non-native.

Etymology. Named for Mark Holdsworth (Tasmania), one of the conservation scientists trying to help endangered parrots, and who collected many of these nest samples.

Figures

FIGURES 9 – 13. Female Nidilaelaps holdsworthi sp. nov. 9, Dorsal shield, paratype (QM S 90160), scale = 100 μm; 10, Epistome, scale = 50 μm; 11, Chelicera, NEST 497, scale = 50 μm; 12, Gnathosoma, holotype, scale = 100 μm; 13, Ventral idiosoma, paratype (QM S 90160), scale = 100 μm.

FIGURES 14 – 16. Male Nidilaelaps holdsworthi sp. nov. 14, Ventral idiosoma, paratype (QM S 90165), scale = 100 μm; 15, Chelicera, paratype (QM S 90162), scale = 50 μm, 16, Femur II, ventral view, paratype (QM S 90164), scale = 25 μm.