Scaptognathus ventridiscus Abé, 1990

Abé, Hiroshi, 2021, Taxonomic review of the subfamily Lohmannellinae (Acari: Trombidiformes Halacaridae) with morphological comparisons among genera, Zootaxa 4980 (2), pp. 201-255 : 237

Scaptognathus ventridiscus Abé, 1990

Diagnosis. Glp-1 not found. Ds-2 on membranous cuticle. PE with 1 dorsal seta. GA bipartite in female, fully sclerotized plate and separated membranous disc in male. Female with 6 Pgs and 6 Sgs. Male with 29–39 Pgs and 6 Sgs. Tr I–IV with 1-1-1-1 setae; Bf I–IV with 2-2-1-1 setae; Tf I–IV with 4-4-3-3 setae, 2-1-0-0 Bp setae; Gn I–IV with 4-5-3-3 setae, 2-1-0-0 Bp setae; Tb I–IV with 9-7-7-7 setae, 6-4-4-4 Bp setae; Ta I–IV with 3-3-3-3 dorsal setae, 1-0-0-0 Bp setae. Lc I with unidentate accessory process. Idiosoma length 350–384 in male (holotype 358), 375 in female, 258 in DN, 133 in LV. Idiosoma width 200–236 in male (holotype 200), 200 in female, 142 in DN, 100 in LV. Gnathosoma length 192–217 in male (holotype 196). Gnathosoma width 100–108 in male (holotype 100). Ratio of gnathosoma to idiosoma 0.55 in male holotype, 0.57 in female, 0.58 in DN, 0.69 in LV. Ratio of P-2 to P-1 4.00 in male holotype.

Remarks. This species is distinguished from other species by the ventral membranosum disc in male. Female, male, DN, LV are known.

Habitat. Intertidal zone: Coarse sands at tidal line.

Distribution. North Pacific Ocean: Oshoro Bay (Hokkaido) [ Japan].

References. Abé (1990a, e), Abé & Green (1994), Bartsch (1994b).

Depository. NSMT, USNMNHW.