Scaptognathus tridens Trouessart, 1889

Abé, Hiroshi, 2021, Taxonomic review of the subfamily Lohmannellinae (Acari: Trombidiformes Halacaridae) with morphological comparisons among genera, Zootaxa 4980 (2), pp. 201-255 : 236

Scaptognathus tridens Trouessart, 1889

Diagnosis. Glp-1 not found. Ds-2 on membranous cuticle. PE with 1 dorsal seta. GA bipartite in female and male. Female with 6 Pgs. Male with 20 Pgs and 6 Sgs. Tr I–IV with 1-0-1-1 setae; Bf I–IV with 2-2-1-1 setae; Tf I–IV with 4-3-3-3 setae, 2-1-0-0 Bp setae; Gn I–IV with 4-4-2-3 setae, 2-1-0-0 Bp setae; Tb I–IV with 8-7-7-7 setae, 5-4-4-4 Bp setae; Ta I–IV with 3-3-3-3 dorsal setae, without Bp setae. Lc I with unidentate accessory process. Idiosoma length 370–450 in adult. Idiosoma width 236 in female (body length 650), 285 in male ( idiosoma length 418). Gnathosoma length 280–330 in adult. Gnathosoma width 133 in female ( gnathosoma length 273). Ratio of gnathosoma to idiosoma 0.67–0.79. Ratio of P-2 to P-1 2.63.

Remarks. This species is distinguished from congeners by the shape of AD, the lack of Glps on dorsum, and the absence of Bp setae on Ta I–IV. Female and male are known.

Habitat. Sublittoral zone: Sandy sediment, sediment with algae, and coarse or shell gravels at 6–18 m depth.

Distribution. North Atlantic Ocean: Roscoff (Bay of Morlaix), Le Croisic (Bay of Biscay) [ France]. West Cork [ Ireland]. Plymouth, Down [ UK]. Mediterranean: Île Riou [ France].

References. Abé (1990c), Abé & Green (1994), André (1940, 1946), Bamber (1982), Bartsch (1978b, 1979a, 1986b, 1994b), Green & Macquitty (1987), Halbert (1915), Lohmann (1893b, 1901), Monniot (1964), Somerfield (1991), Trouessart (1889a, 1893, 1896a), Trouessart & Neumann (1894a, 1894b).

Depository. MNHNP (?).