Scaptognathus Trouessart, 1889

Bartsch, Ilse, 2015, The genital area of Halacaridae (Acari), life stages and development of morphological characters and implication on the classification, Zootaxa 3919 (2), pp. 201-259 : 229-230

Scaptognathus Trouessart, 1889

Type species. Scaptognathus tridens Trouessart, 1889 .

Adults. Adults with GA by fusion of GP and AP. Female GA often bi- or tripartite, with two or three transversely separated and differently ornamented parts. Posterior part of female GA with two to four pairs of pgs, genital sclerites with zero to two pairs of sgs. Two pairs of internal gac at and just beyond middle of length of GO ( Abé 1990b: fig. 1E, 3F, 2012: fig. 1E). Ovipositor short. Number and shape of genital spines not known. Male GA uniform or bipartite. Posterior part of GA with 5–33 pairs of pgs lateral and posterior to GO ( Newell 1984: fig. 795; Bartsch 1986d: fig. 28, 1993c: fig. 13K). Two to three pairs of sgs on genital sclerites, two pairs of gac within genital cavity ( Abé 1990b: fig. 3E; Bartsch 2003d: fig. 16). Adults with pair of epimeral pores on AE.

Juveniles. With deuto-, protonymph and larva. In deuto- and protonymph GP either separated or immediately adjacent to AP. GP uniformly sculptured or bipartite. Deutonymphal GP with two pairs of internal gac, two pairs of pgs and zero to one pair of sgs ( Bartsch 1973a: fig. 82, 1977b: figs 340, 356). Protonymphal GP with single pair of gac and zero to one pair of setae ( Bartsch 1977b: fig. 355; Abé 1990b: fig. 4F, 2012: fig. 1H). These setae small and close to primordial genital slit. All juveniles with pair of epimeral pores.

Remarks. The genus, with 31 described species, has been found in all oceans, in tropical and temperate zones ( Bartsch 2009a; Abé 2012).