Pomerantziidae Baker

Fan, Qing-Hai & Chen, Yan, 2005, A review of the Pomerantziidae (Acari: Prostigmata: Pomerantzioidea), with the description of a new genus, Zootaxa 1037, pp. 1-22 : 2-4

Pomerantziidae Baker

Pomerantziidae Baker, 1949: 269 ; Cunliffe, 1955: 213; Krantz, 1970: 159; Price, 1971: 395; Krantz, 1978: 255; Kethley, 1982: 126.

Type genus: Pomerantzia Baker, 1949: 269 .

Diagnosis

ADULT FEMALE

Gnathosoma ( Figs. 1–3 ). Projecting in front of podosoma. Chelicerae ( Fig. 1 B) basally separate, conical, each with a subterminal seta (cha); movable digit blade­like, fixed digit vestigial; with a pair of small peritremes at bases of chelicerae. Palps ( Fig. 1 C) stout, tibial claw prominent, accessory claw conical; terminal palptarsal eupathidia setiform; counts of setae and solenidia from coxa to tarsus: 1 elcp, 0, 1, 1, 2 + 1 terminal claw + 1 accessory claw, 4 + 1 + 4 eupathidia. Subcapitulum ( Fig. 2 B) stumpy, with 2 pair of rostral setae and 1 pair of subcapitular setae (m).

Idiosoma ( Figs. 1–2 ). Narrow, elongate. Prodorsum ( Fig. 1 A) with a large shield bearing 1 pair of vertical setae and 2 pairs of scapular setae. Trichobothria and eyes absent. Dorsal hysterosoma with 5 shields and 5 series of dorsal idiosomal setae: c, d, e, f, and h (pseudanal setae ps1–3 are associated with the anal opening and often terminally located); c ­series with 2 pairs of setae; d ­series and e ­series each with 1 pair of setae; f ­series and h ­ series each with 2 pairs of setae. Ventral idiosoma ( Fig. 2 A): coxae II and III widely separate; ventral setae 1a, 2a, 3a and 4a present; with a pair of ventrolateral shields prior to coxae III, separate or fused with coxae III; ventral opisthosoma with a fused aggenital shield which bearing 2–4 pairs of aggenital setae; genital valves surrounded by aggenital shield, bearing 2–5 pairs of genital setae, genital opening longitudinal, with an ovipositor and 3 pairs of genital discs inside; anal valves apart from genital valves, bearing 3 pairs of pseudanal setae.

Leg ( Fig. 3 ). Leg I and IV obviously longer than leg II and III; all tarsal claws stout and nude; empodium absent; counts of setae and solenidia on legs I–IV: coxae (including 1a, 2a, 3a and 4a) 4 + 1–2 pegs, 4, 3–4, 3–4; trochanters 1, 1, 2, 1; basifemora 5, 4, 3, 3; telofemora 5, 5, 4, 5; genua 10–12 + 1, 5, 5, 5–6; tibiae 12 + 3, 5 + 1, 5 + 1, 8–9 + 1; tarsi 16–19 + 6–8, 13–14 + 2–6 + 1, 11, 11–12.

ADULT MALE

Unknown.

TRITONYMPH

Similar to adult female, but differs in: genital valves with 2–4 pairs of setae; aggenital valves with 3 pairs of setae; counts of setae and solenidia on genu I: 10–11 + 1; tibia IV: 7–8 + 1; tarsi I–II: 16–19 + 6–7, 13–14 + 2–5.

DEUTONYMPH

Similar to adult female, but differs in: genital valves with 2 pairs of genital discs and 1–2 pairs of genital setae; aggenital valves with 2 pairs of setae; counts of setae and solenidia on coxae I–IV: 4 + 1 peg, 4, 4, 2; basifemora I–IV: 5, 3, 3, 1; telofemur IV: 4; genua I and IV: 8 + 1, 5; tibiae I and IV: 10 + 2, 6–7 + 1; tarsi I, II and IV: 17 + 5–6, 13–14 + 2, 11.

PROTONYMPH

Similar to adult female, but differs in: genital valves with 1 pair of genital discs and 1 pair of genital setae; aggenital valves without setae; counts of setae and solenidia on coxae I–IV:? + 1 peg,?, 3, 0; trochanter IV: 0; basifemora II and IV: 3, 0; telofemur IV: 0; genua I and IV: 7 + 1, 0; tibiae I and IV: 9 + 2, 2; tarsi I, II and IV: 17 + 5, 13 + 3, 8.

LARVA

Peritreme absent; rostrum with 1 pair of setae; with a pair of urstigmata between coxae I and II; without genital discs, genital and aggenital setae; leg IV absent; counts of setae and solenidia on legs I–III: coxae 2 + 1 peg, 1, 2; trochanters 0, 0, 1; basifemora 1, 1, 1; telofemur 5, 5, 4; genua 5 + 1, 5, 5; tibiae 8 + 2, 5 + 1, 5 + 1; tarsi 16 + 2, 12 + 2, 11.

Remarks

At first, the family was considered to be closely related to Raphignathidae­ Stigmaeidae­Caligonellidae complex and Pseudocheylidae ( Baker 1949) . Cunliffe (1955) listed the family in the superfamily Raphignathoidea, but mentioned that it might belong elsewhere. Having noticed the unusual characters of having genital suckers, numerous solenidia on tarsus I and lacking tarsal a pulvillus, Southcott (1957) excluded Pomerantziidae from Raphignathoidea. In his key to families of Raphignathoidea, Summers (1966) also omitted it from the superfamily. Although Krantz (1970, 1978) included Pomerantziidae in the Raphignathoidea in his authoritative books most acarologists have not followed his opinion. Presently, it is retained in its own superfamily Pomerantzioidea Wainstein, 1965 ( Kethley 1982, 1990). The phylogenetic relationships of Pomerantzioidea are yet clearly resolved. However, the cladograms proposed by Norton et al. (1993) provided a reasonable hypothesis for the position of Pomerantzioidea within the Prostigmata. The clade Eleutherengona is strongly supported by the lack of a naso. Members of Pomerantzioidea have the following ancestral characters: (1) cheliceral setae present, (2) leg femora subdivided, (3) larval instar having urstigmata between coxae I and II, (4) postlarval instars with genital papillae, and (5) adults with eugenital setae, which are shared by Paratydeidae , Stigmocheylidae, Pseudocheylidae and some Heterostigmata. Members of Pomerantzioidea and (((Tetranychoidea and Cheyletoidea) Raphignathoidea) Pterygosomatoidea) share the following derived characters: (1) prodorsum without trichobothria, (2) opisthosoma of larval and postlarval instars with five segements (C, D, E, F and PS), (3) legs without bothridial setae.

Several characters indicate that mites in Pomerantziidae are adapted to the underground soil habitat. The stout claws, missing empodia and greatly enlarged legs I are suitable for digging. The elongate cylindrical­shaped body allows easy movement through the soil. The enlarged ventral setae on tibiae and tarsi II–IV provide support points for forward movement.

Characters for separating stages and species are listed in Table 1 and Table 2 . Keys to stages of the family and to genera and species are provided below.

Figures

FIGURE 1. Pomerantzia subterranea sp. n. (adult female). A, dorsal view of idiosoma; B, dorsal view of gnathosoma; C, palp.

FIGURE 2. Pomerantzia subterranea sp. n. (adult female). A, ventral view of idiosoma; B, subcapitulum; C, genito­anal area; D, E, ovipositor.

FIGURE 3. Pomerantzia subterranea sp. n. (adult female). A, leg I; B, leg II; C, leg III; D, leg IV.