Atractides

Gerecke, Reinhard, 2003, Water mites of the genus Atractides Koch, 1837 (Acari: Parasitengona: Hygrobatidae) in the western Palaearctic region: a revision, Zoological Journal of the Linnean Society 138, pp. 141-378 : 184-185

ATRACTIDES CURVISETUS ( KOENIKE, 1911)

Megapus curvisetus Koenike, 1911

Species dubia

Type series: Holotype, SMNH 1144 Megapus curvisetus Koen. ♀ Type; Westf., in der Henne Dr Thienemann coll., 18.8.1908. State of conservation: good, left I-L and right IV-L missing.

Description: Female (holotype, male unknown) integument striated (7/10 Mm), glandularia with slightly irregular contour line, but without secondary sclerotization, maximum diameter 36 Mm; mediocaudal margin of Cx-1 + 2 truncate, apodemes of Cx- 2 in a right angle to the median line. I-L-5 thickened with doubled ventral seta, S-1 curved and truncate, probably misshaped (internally with a curious transverse partition line) I-L-6 relatively short (L ratio I-L-5/6 1.53); pregen crescent-shaped, large, genital plates compact, contour without incisions, Ac in an obtuse angle, Ac-1–3 L 46, 46, 60 Mm; excretory pore smooth, Vgl-1 not fused to Vgl-2; palp inconspicuous, with nearly straight ventral margins of P-2 to -4, insertions of ventral hairs of P-4 dividing the ventral margin 1: 1: 1, sword seta halfway between the two hairs, not extremely elongated (as stated by K. Viets, 1936).

Discussion: The original description was provided without any discussion of diagnostic characters, mainly dealing with measurement data and morphological details generally found in all Atractides species. Obviously, Koenike interpreted the shape of S-1, on which he based the name, to be an important feature of this taxon. The strange internal structure of this seta suggests that its shape is caused by developmental disturbance (an interpretation corroborated also by the unusual doubling of the ventral seta in the centre of the segment). Of the species known at that time, A. curvisetus is most similar to A. nodipalpis . In the latter, a wide range of variation of the shape of the pregen can be observed, from a rather short, transverse rod to a sickle-shaped sclerite as in A. curvisetus . A. curvisetus differs from A. nodipalpis only in the truncate posteromedial margin of Cx-1 + 2 with apodemes in right-angled position. Due to the damage and individually aberrant features of the single specimen on which A. curvisetus is based, the species must be designed a species dubia.

ATRACTIDES MONTANUS ( HALBERT, 1911)

( FIG. 23A–D )

Megapus spinipes nov. var. montanus Halbert, 1911

Figures

Figure 23. Atractides montanus, ♀ lectotype (NHMB). A, coxal field; B, genital field; C, palp, medial view; D, I-L-5 and -6. Scale bars = 100 µm.