Scaptognathus gibbosus Bartsch, 1977

Abé, Hiroshi, 2021, Taxonomic review of the subfamily Lohmannellinae (Acari: Trombidiformes Halacaridae) with morphological comparisons among genera, Zootaxa 4980 (2), pp. 201-255 : 229

Scaptognathus gibbosus Bartsch, 1977

Diagnosis. Ds-2 on membranous cuticle. PE with 1 dorsal seta. GA bipartite in female and male. Female with 4 or 5 Pgs and 0 Sgs. Male with 12 Pgs and 4 Sgs. Tr I–IV with 0-0-1-1 setae; Bf I–IV with 2-(1,2)-(1,2)-1 setae; Tf I–IV with 2-2-(1,2)-1 setae, without Bp seate; Gn I–IV with 5-4-2-2 setae, 2-0-0-0 Bp setae; Tb I–IV with 6-5-5-5 setae, 3-2-2-2 Bp setae; Ta I–IV with 3-3-3-3 dorsal setae, 1-0-0-0 Bp setae. Lc I with either no or fine accessory process. Idiosoma length 129–182 in female, 151–176 in male, 142–158 in DN, 112–117 in PN. Idiosoma width 86–123 in female, 88–114 in male, 79 in DN, 77 in PN. Gnathosoma length 137, 153 ( idiosoma length 175) in female, 124–135 ( idiosoma length 155–163) in male, 124–133 in DN, 107–112 in PN. Gnathosoma width 60, 74 ( idiosoma length 175) in female. Ratio of gnathosoma to idiosoma 0.78–0.87 in female, 0.80–0.83 in male, 0.84–0.87 in DN, 0.96 in PN.

Remarks. This species is similar to S. pacificus in the body size and the possession of 3 Bp setae on Tb I. However, S. gibbosus is distinguished from the latter by the absence of Bp setae on Tf I and the presence of a single Bp seta on Ta I. A dorsal seta is present at the proximal portion of P- 2 in the Somarian and Brazilian specimens ( Morselli & Mari 1986, Pepato et al. 2011). On the other hand, the proximal seta is not found on P- 2 in the original figuration in Bartsch (1977a). Female, male, DN, and PN are known.

Habitat. Littoral zone: Sediment at littoral zone.

Distribution. South Pacific Ocean: Bartholomé, Santa Cruz (Galapagos Is.) [ Equador]. Indian Ocean: Sar Uanle [ Somalia]. South Atlantic Ocean: São Francisco [ Brazil].

References. Abé (1990c), Abé & Green (1994), Bartsch (1977a, 1994b), Bartsch & Schmidt (1978), Morselli & Mari (1986), Pepato et al. (2011).

Depository. ZIZMH.