Halacarus perditus Newell, 1984

Bartsch, Ilse, 2011, Halacarus socius (Acari: Halacaridae), description of the male and diagnoses of species of the Halacarus actenos group, Zootaxa 2800, pp. 18-40 : 33-34

Halacarus perditus Newell, 1984

Halacarus perditus: Newell (1984: 56, figs 108–109) .

Diagnosis. Length of female 588 µm. AD long, slender, frontal spine extending to or beyond distal end of P-2. Length of spine equalling 0.4 and almost 0.2 times that of AD and idiosoma, respectively. Posterior part of AD triangular. Pair of glp-1 at 0.7 relative to length of AD. Pair of ds-1 situated at 0.8, i.e. about halfway between glp-1 and posterior margin of AD and distinctly posterior to level of glp-1. Ocular plate ovate, rather wide, without cornea; canaliculus in posterior margin of OC. Pair of ds-5 anteromedial to glp-4, ds-6 medial to glp-5, both ds-5 and ds-6 removed from gland pores by a distance equalling about three times glp diameter. Anterior margin of female GA widely ovate ( Newell 1984: fig. 109), according to the text ( Newell 1984: 56), anterior margin of GA cordiform and cerotegument absent in anteromedian part of GA (absence not shown in fig. 109). Distance from anterior pair of pgs to margin of GA same as interval between anterior margins of GA and GO.

Integument of legs punctate. Trochanters I to IV with 1, 1, 3, 1 setae. Both ventromedial setae on tibia II bipectinate. Tarsi I to IV with 2, 1–2, 1, 1 ventral setae ( Newell 1984: 50, 56). Tarsi III and IV with four and three dorsal setae, respectively. Paired claws of all tarsi with accessory process but without pecten.

Remarks. According to Newell (1984: 56), females of H. perditus have a cordiform anterior GA margin, but this is not illustrated ( Newell 1984: fig. 109), the other characters are typical of species which belong to the H. actenos group.

Halacarus perditus has rather wide OC and the ds-1 are distinctly posterior to the gland pores, at 0.8 relative to the length of AD. Characters to distinguish between H. nitidus and H. perditus are mentioned above. Distribution and ecology. A single record is from the southeastern Pacific, collecting data 43°15’S and 97°41’W, at 178–265 m depth.