Hypoaspis muellerae, Halliday, R. B., 2005

Halliday, R. B., 2005, Predatory mites from crops and pastures in South Africa: potential natural enemies of redlegged earth mite Halotydeus destructor (Acari: Penthaleidae), Zootaxa 1079, pp. 11-64 : 32-34

Hypoaspis muellerae sp. nov. (Figs 16–20)

Specimens examined: Holotype female, Plettenberg Bay, 18.viii.1994, roadside picnic area, T. K. Qin coll., clover and capeweed, site 30–13 (= 94­13). Paratypes, 6 females, same data as holotype.

Description (Female)

Dorsal idiosoma (Fig. 16). Length 575–662 µm, maximum width 374–412 µm (n=5). Dorsal shield oval shaped, posteriorly truncate, surface smooth with some indistinct posterior polygonal ornamentation, with ca. 90 setae, many irregularly placed and asymmetrical, several unpaired median setae in the Zx region, most setae minute, 9–18 µm long, except Z5 much longer, ca. 45 µm.

Ventral idiosoma (Fig. 17). Tritosternum with rectangular base and lightly pilose laciniae; pre­sternal shields conspicuous, oval shaped, not fused with sternal shield, sternal shield wider than long, with three pairs of conspicuous setae, with polygonal ornamentation anteriorly, posteriorly smooth; genito­ventral shield large, expanded behind coxae IV, with one pair of genital setae and polygonal ornamentation, flanked by abutting elongate metapodal plates; metasternal setae inserted in soft skin between anterior margin of genital shield and triangular exopodal shields; anal shield triangular, anterior margin covered by posterior margin of genital shield, bearing a pair of para­anal setae and an unpaired post­anal seta, cribrum very narrow; soft skin laterad of genital shield with ca. 10 pairs of opisthogastric setae, each inserted in a minute platelet; dorsal shield extending slightly onto ventral idiosoma; peritrematal shields extending from anterior margin of coxa I to behind coxa IV, with a pointed post­stigmatal extension.

Gnathosoma . Hypostomal groove with 6 transverse rows of denticles, each with 3–4 blunt teeth; anterior hypostomal seta (h1) and interior posterior hypostomal seta (h3) subequal in length (ca. 40 µm), exterior posterior hypostomal seta (h2) and palp coxal seta shorter (ca. 16 µm) (Fig. 18); corniculae robust, extending to anterior margin of palp femur. Fixed digit of chelicera with two blunt teeth and a terminal hook, pilus dentilus fine, short, dorsal seta short, curved; movable digit with two triangular teeth and a terminal hook (Fig. 19). Epistome curved, with a few minute serrations (Fig. 20). Palp tarsal claw with two subequal tines.

Legs. Chaetotaxy: Leg I. coxa 0 0/1 0/1 0; trochanter 1 0/2 1/1 1; femur 2 2/1 3/3 2; genu 2 3/2 3/1 2; tibia 2 3/2 3/1 2. Leg II. coxa 0 0/1 0/1 0; trochanter 1 0/2 0/1 1; femur 2 3/1 2/2 1; genu 2 3/1 2/1 2; tibia 2 2/1 2/1 2; tarsus 3 3/2 3/2 3 + mv, md. Leg III. coxa 0 0/ 1 0/1 0; trochanter 1 0/2 0/1 1; femur 1 2/1 1/0 1; genu 2 2/1 2/1 1; tibia 2 1/1 2/1 1; tarsus 3 3/2 3/2 3 + mv, md; Leg IV. coxa 0 0/1 0/0 0; trochanter 1 0/2 0/1 1; femur 1 2/1 1/0 1; genu 2 2/1 3/1 1; tibia 2 1/1 3/1 2; tarsus 3 3/2 3/2 3 + mv, md. All setae fine, smooth, pointed. All legs with two well­developed claws and a rounded membranous pulvillus.

Notes

It is difficult to place this species in a genus and/or subgenus in existing classifications. In the keys of Evans & Till (1966) and Van Aswegen & Loots (1970) it runs to Pneumolaelaps , on the basis of the chaetotaxy of genu IV (2 2/1 3/1 1), the presence of uniformly short needle­like dorsal idiosomal setae, and the presence of unpaired setae Zx. However, in the classification of Evans & Till (1979) this species is excluded from Pneumolaelaps because the opisthogastric cuticle is not hypertrichous, and it runs to Hypoaspis sens . lat. Furthermore, species of Pneumolaelaps are stated to be exclusively associated with bumblebees. In Karg's (1979) key to species of Hypoaspis , this species would be a member of the Hypoaspis (Holostaspis) tridentata species group. It differs from all other members of that group in having uniformly very short dorsal shield setae (with the exception of Z5), none of which are long enough to reach the next seta in series. However, it does not agree with Holostaspis in the sense of Evans & Till (1979), because it has long normally­developed cheliceral digits (movable digit ca. 37 µm long). This situation is typical of the highly unsatisfactory state of the classification of the freeliving Laelapidae , especially of the species placed in Hypoaspis sens . lat.