Nidilaelaps annectans (Womersley)

Joharchi, Omid, Ueckermann, Edward A., Döker, Ismail, Khaustov, Vladimir A. & Hänel, Christine, 2021, Some free-living laelapid mites (Acari: Mesostigmata: Laelapidae) from Tristan da Cunha and Nightingale Islands, with description of a new species of Gaeolaelaps Evans & Till (Acari: Laelapidae) and the first afrotropical record of the genus Nidilaelaps Shaw, Zootaxa 5026 (2), pp. 271-285 : 280

Nidilaelaps annectans (Womersley)

( Figs 23–29 )

Gymnolaelaps annectans Womersley, 1955: 419 .

Gymnolaelaps annectans .— Farrier & Hennessey, 1993: 73.

Hypoaspis nidicorva . — Evans & Till, 1966: 179 (synonomy by Domrow, 1973: 63).

Pseudoparasitus annectans .— Hunter, 1966: 12.

Pseudoparasitus (Gymnolaelaps) annectans . — Karg, 1978b: 206; 1981: 218; Tenorio, 1982: 268.

Hypoaspis (Laelaspis) nidicorva . — Karg, 1979: 100.

Specimens examined. Four females, Edinburgh Settlement, Tristan da Cunha Island, 37°06’ S, 12°30’ W, 20 Feb. 2005, alt. 100 ft., C. Hänel coll., from Chicken meal; four females, Nightingale Island , 37°25’ S, 12°28’ W, 03 April 2005, C. Hänel coll., from tussock grassland riddled with sea-bird burrows .

Remarks. The type species of the genus, Nidilaelaps annectans , was described from Australia ( Womersley, 1955) where it was recorded from nesting material in burrows of the mutton bird. It has been recorded from nests of birds or small mammals and soil, from Argentina, Papua New Guinea, Australia, New Zealand, Great Britain, Hawaiian Islands and is now recorded from Tristan Da Cunha and Nightingale Islands for the first time. It was found there in both a native habitat and imported stored food. Domrow (1973) considered N. annectans as a junior synonym of Hypoaspis nidicorva Evans & Till, 1966 . However, Domrow (1973) did not provide any explanation for this decision, nor did he provide the details of the examined specimens. Hypoaspis nidicorva was described from Great Britain ( Evans & Till, 1966), where it was found in the nest of a jackdaw. We have not had the opportunity to examine the type specimens of these species. Nonetheless, in the process of comparing the descriptions and figures of these species with our observations of the Tristan and Nightingale specimens, they agree very well with the description given by Evans & Till (1966). We could not find any authentic distinguishing morphological differences, except that the dorsal shield setae are slightly longer in H. nidicorva , especially the central and opisthonotal setae, which mostly reach to base of next setae in H. nidicorva (see Fig. 23 ), while in N. annectans dorsal shield seta shorter and never reach to base of next setae (see Fig. 1 , in Shaw, 2012). We believe that such morphological difference could be due to intraspecific variation among two different geographical zones. Therefore, in this study, we follow Domrow’s (1973) treatment and provisionally retain these two species as synonyms until further comparative studies based on directly examining the type material of both species is possible to clarify their relationship. Shaw (2012) suggested Nidilaelaps is endemic to the Australopapuan region and the presence of N. annectans in other regions is facilitated by its many phoretic associations, particularly with birds and rodents. We agree with his postulation but with our findings, this genus is now recorded from Afrotropical realm for the first time. The species may be recognised primarily by the dorsal shield bearing 39 pairs setae plus one to two supernumerary Jx setae between J4 setae ( Fig. 23 ), sternal shield reticulate throughout and posterior margin of sternal shield usually with mild medial point ( Figs 24 & 25 ), genito-ventral shield furnished with lateral zone of longitudinally aligned cells and bears four pairs setae (st5, Zv1, Jv1, Jv2) (see Figs 24 & 26 ), poststigmatal plate shield fused to exopodal IV ( Fig. 27 ), deutosternal groove wider anteriorly with six deutosternal rows of 5–10 denticles ( Fig. 28 ), epistome with a smooth edge ( Fig. 29 ).

Figures

FIGURES 23–29. DIC micrographs of Nidilaelaps annectans (Womersley, 1955), female. 23, dorsal idiosoma; 24, ventral idiosoma; 25, sternal shield; 26, genital shield; 27; details of peritrematal shield; 28, subcapitulum; 29, epistome.

FIGURES 1–4. 1–2. DICmicrographs of Cosmolaelaps claviger (Berlese, 1883), female. 1, dorsal idiosoma; 2, ventral idiosoma. 3–4. DIC micrographs of Gaeolaelaps aculeifer (G. Canestrini, 1884), female. 1, dorsal idiosoma; 2, ventral idiosoma.