Raptorhydracarinae, Pešić, Vladimir & Gerecke, Reinhard, 2014

Pešić, Vladimir & Gerecke, Reinhard, 2014, Water mites from caves of the Ha Giang province, northern Vietnam (Acari: Hydrachnidia), Zootaxa 3774 (4), pp. 367-380 : 375

Subfamily Raptorhydracarinae subfam. nov.

Diagnosis. Idiosoma flattened, ocular pigment absent; integument lined, dorsum with two unpaired plates, both wider than long; except for postocularia (in central position on anteriror plate), and Dgl-1 and –2 (together with praeocularia on paired transverse frontal platelets) all glandularia and setae in the soft integument of the dorsal furrow, but some of them associated to posterior plate: one pair in an elongate, posteriorly directed indentation of the lateral margin, and two pairs in shallow bays in the lateral part of the posterior margin. Gnathosoma not fused to anteromedial margin of Cx-I. Coxae fused forming a nearly circular disk, posteromedial margin of Cx-IV flanking posterior edge of genital field; suture lines Cx-I/II, Cx-II/III and Cx-III/IV not reaching the medial line; Cx-III without conspicuous glandularia; IV-L insertions covered by rounded extensions of Cx-IV. Legs without swimming setae, I–L-2–5 each with a pair of serrate ventrodistal setae, those of I–L-4/-5 basally thickened and very long. IV-L with simple claws. Genital field bearing three pairs of Ac on paired elongate movable flaps.

Palp: P-1 without setae, P-2 ventral margin straight with rounded ventrodistal edge, a small ventral peg-like seta in proximal half of segment, ventral denticulation indistinct, P-3 with a serrate seta at ventrodistal margin, P-4 bearing 5–8 short, but strong ventral denticles, and a serrate seta at ventrodistal edge, P-5 very long, longer than P-4, gradually tapering to a pointed tip bearing 7–9 short, denticle-like setae on ventral side.

Type genus. Raptorhydracarus gen. nov.

Etymology. The name refers to modifications of P-4 and - 5 forming an unique ‘raptorial’ organ.

Remarks. The combination of acetabula placed on paired elongate movable flaps and P-2 with a peg-like ventral seta suggests to place Raptorhydracarus within the family Limnesiidae , but the character set defining Raptorhydracarus isolates it considerably and requires the introduction of a new subfamily. The following character combination is not found in other limnesiids: (1) Coxal shield posteriorly extending and reaching posterior edge of genital field; (2) Cx-III without Cxgl-4 (often called " Glandulae Limnesiae "); (3) IV–L with simple claws; (4) P-4 and P-5 modified to form a unique ‘raptorial’ organ where the gripping surfaces are formed by the opposing faces of the two successive segments.

The combination of pointed tubercles on ventral side of P-4 and a long, pointed P-5 is found similarly in the monotypic subfamily Kawamuracarinae ( Cook 1974). Species of the genus Kawamuracarus differ in character states such as: (1) presence of Cxgl–4 on Cx-III; (2) dorsum with three small plates; (3) coxae not fused to form a ventral shield flanking genital field and (4) ventral tubercles on P-4 very long, together placed on a broad-based extension.