Atractides laetus, LUNDBLAD

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 : 303-305

ATRACTIDES LAETUS LUNDBLAD, 1962

Syn. to A. samsoni ( Sokolow, 1936) : syn. nov.

Type series: Holotype ♀, SMNH 5325 . Typ.; Atractides laetus Ldbl. ♀ Blek. Kristianopel Bäck vid Brämsebro 14.6.1934 Leg. O. Lundblad. State of conservation: dorsum of idiosoma lost, gnathosoma in situ, both palps and I-L separate, laterally.

Discussion: Lundblad’s original description of A. laetus was based on two female specimens, and he restricted the discussion of diagnostic features to a comparison with A. tener . Biesiadka (1978) provided a description of the male and additional morphological details of females, but again compared the species only with A. tener . Both authors were unaware of the similarity to A. samsoni from Russia. In view of the characteristic combination of a striated integument, smooth excretory pore, Vgl-1 + 2 not fused, slightly modified I-L with homoiomorphic S-1 and -2, and a palp with ventrodistal protrusion in both sexes, there is much evidence that the population described by Biesiadka is conspecific with the types of A. laetus from Sweden. On the other hand, a comparison of measurements including a detailed analysis of Biesiadka’s figures reveals only minor differences in absolute values with the type of A. samsoni , but a nearly perfect agreement in all proportions. Differences which concern the most important dimensions in the type of A. samsoni (e.g. L I-L-5/6 170/145 Mm, S-1 and -2 longer with wider interspace, genital field larger) are possibly the effect of different measurement standards. The extension of the male genital field in A. samsoni has been increased by crushing and by the presence of an additional supranumerary acetabulum. A further slight difference found in the position of the sword seta on P-4 (halfway between the ventral hairs in the types of A. laetus and A. samsoni , but nearer the distoventral hair in the Polish population) could at best indicate a genetic separation of the Polish specimens. However, the insertion of this seta was found to be variable to a certain extent also in other species. There is thus no reason to doubt the synonymy of A. laetus with A. samsoni .

ATRACTIDES NEUMANI (LUNDBLAD, 1962)

( FIG. 73A–F )

Atractides nodipalpis neumani Lundblad, 1962b

Type series: Holotype ♂, SMNH 5318 Typ., Atractides neumani Ldbl. ♂ Hälsingland: Färila. Svartån vid Kilbo 15.6.1923 leg. O. Lundblad. State of conservation: perfect, gnathosoma in situ, both palps and both I-L separate, laterally, genital skeleton separate, posteriorly . Paratype ♀, SMNH 5319 . Allotyp, label and state as holotype .

Description:

General features dorsal integument: striated; muscle attachments: smooth coxal field: slender, with rather long median suture Cx-1 + 2

I-L: I-L-5 robust, with homoiomorphic S-1 and -2

excretory pore: smooth; Vgl-1: not fused to Vgl-2

palp: weak sexual dimorphism

Male

Holotype genital field: anterior margin convex, posterior margin weakly indented, Ac triangular; genital setae: 44, in a dense row flanking the gonopore, but in scattered arrangement at the lateral and posterior margins palp: ventral margin P-2 convex, but not forming a ventrodistal projection, P-

3 straight, P-4 2: 2: 1, slightly elevated near insertion of proximoventral hair, sword seta near proximoventral hair idiosoma L/W 500/405; glandularia 22 coxal field L 310; Cx-3 W 338; Cx-1 + 2 mL 136, IL 210, W 265 I-L-5 dL 159, vL 116, dL/vL 1.37, HA-HC 40, 47, 54, dL/HB 3.38 S-1 L 79, L/ W 11.3, S-2 L 70, L/ W 7.8, interspace 13, L S-1/2 1.13 I-L-6 L 121, HA-HC 24, 19, 17, dL/HB 6.37; L I-L-5/6 1.31 genital field L/W 112/121, Ac-1–3 L 32, 37, 32 gnathosoma vL 108; chelicera –

Figures

Figure 73. Atractides neumani. A, B, paratype ♀ SMNH 5319, C–F, holotype ♂ SMNH 5318. A, ♀ palp, medial view; B, ♀ genital and postgenital field; C, ♂ I-L-5 and -6; D, ♂ palp, medial view; E, ♂ coxal field; F, ♂ genital and postgenital field. Scale bars = 100 µm.