Neocrassicheles, Mašán & Halliday, 2010

Mašán, Peter & Halliday, Bruce, 2010, Review of the European genera of Eviphididae (Acari: Mesostigmata) and the species occurring in Slovakia 2585, Zootaxa 2585, pp. 1-122 : 63-64

Genus Neocrassicheles gen. nov.

Type species: Neocrassicheles sternomus sp. nov.

Description (adults). Dorsal idiosoma ( Figs 113, 116, 117). Idiosoma of female subglobular, almost hemispherical, subcircular in outline, very weakly sclerotised, smooth and transparent, dorsal shield not apparent. Idiosoma of male well sclerotised, dorsal shield entire, suboval, completely covering dorsal idiosoma, lateromarginal strip of dorsal shield expanded onto ventral surface; shield mostly smooth or with weak longitudinal sculptural lines close to ventrolateral margins, fused to anterior sections of peritrematal shields anterolaterally (also in deutonymph), widely expanded ventrally, and bearing 30 pairs of setae of which at least eleven pairs in ventral position. Vertex flat and poorly developed. Dorsal setae simple, mostly fine, short, needle-like, only slightly differing in length; vertical setae j1 relatively short and inserted close to anterior margin ( Fig. 113). Interscutal integument smooth, not striated. Pore-like structures small and subcircular; in females three pairs of pores markedly enlarged.

Ventral idiosoma ( Figs 58, 109). Presternal platelets absent. In female, most of ventral surface very weakly sclerotised, smooth and transparent. Sternal area without distinct shield, but with robust suboval protuberance bearing two pairs of sternal setae st1 and st2 and two pairs of pores; setae st2 placed on additional submedial tubercle ( Fig. 58); setae st3 placed on very weakly sclerotised integument; metasternal setae st4 placed on almost unsclerotised integument, associated pores not visible, metasternal platelets absent. All sternal setae st1–st5 short, needle-like, subequal in length. Perigenital region more sclerotised than other idiosomal surface. Epigynal shield well defined, small, narrow, moderately rounded posteriorly, with hyaline anterior section produced into a long medial point; genital setae outside the shield, genital pores not visible. Male sterno-genital shield oblong, acuminate posteriorly, with conspicuous genital orifice anteriorly, well sclerotised, reticulate anteriorly and marginally, with four pairs of sternal setae and three pairs of small slitlike pores. Endopodal platelets II–III and III–IV elongated, slightly widened, connected each to other (also in deutonymph), and fully (endopodals II–III) or partly (endopodals III–IV) incorporated into sterno-genital shield; this scutal fusion often delicately indicated by sculptural suture; two poststerno-genital sclerites present. In female, endopodal, exopodal and metapodal platelets absent. Anal shield very indistinct in female; in male free, well sclerotised, smooth or weakly ornamented, subtriangular, bearing three needle-like circumanal setae, relatively large anus and well developed cribrum. Opisthogastric integument with nine pairs of setae in female, seven pairs in male (excluding st 5 in both sexes). In male, exopodal platelets I–III absent; exopodals IV narrow and curved; metapodal platelets present, slit-like and poorly sclerotised. Peritremes well developed, long, anterior end reaching beyond anterior margin of coxa I. Peritrematal shields present only in male, developed along the whole peritreme, anteriorly connected to dorsal shield between setae z1 and s2, with short, tapered post-stigmatic section; post-stigmatic pore outside shield. All ventral setae simple and needle-like.

Gnathosoma . Palptarsus without paired macroeupathidia. Cheliceral segments slightly elongated in female ( Fig. 110), shorter and stouter in males ( Fig. 116); cheliceral digits relatively robust (especially in males and deutonymphs); movable digit with two subdistal teeth in female or with one robust subdistal tooth in male ( Fig. 130); short tubular spermatodactyl directed almost perpendicularly to the longitudinal axis ( Figs 129, 130). Epistome with wide flat base produced into long, robust and spiniferous central projection and four to seven lateral spines on each side of the projection ( Figs 122, 123); lateral spines simple or bifurcate; basal part of central projection spiniferous in adults or mostly smooth in deutonymph ( Figs 120, 121).

Legs. Setation of legs I-II-III-IV: coxae 2-2-2-1, trochanters 6-5-5-5, femora 13-11-6-6, genua 10-11-8-7 and tibiae 10-10-7-7 ( Table 3). Lateral lobes of pulvillus on female legs II–IV modified, elongated and distally pointed, projecting beyond claws ( Fig. 111). Male leg segments not spurred.

Etymology. The genus name Neocrassicheles refers to the similarity of the new genus to the related genus Crassicheles .

Notes on the genus. Adults and deutonymphs of Neocrassicheles share a variety of morphological and ecological characteristics with those of Crassicheles and Uroiphis , as follows: (1) distinct sexual dimorphism in the shape of the idiosoma: females subglobular, males dorso-ventrally flattened; (2) pointed anterior margin of epigynal shield in the female; (3) substantial reduction of some setae on the opisthogastric soft integument in males, so only seven pairs are present, excluding st5; (4) sterno-genital shield mostly with four pairs of sternal setae, not capturing sternal setae st5; (5) robust cheliceral segments and digits; (6) unusual phoretic behaviour in which only the males and deutonymphs are phoretic; (7) phoretic preference for flies rather than beetles. The new genus differs from Crassicheles and Uroiphis by the features presented in the Table 6. The genus is monotypic, based on material from Slovakia.