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 : 212-213

ATRACTIDES BARSIENSIS ( SZALAY, 1929)

Megapus barsiensis Szalay, 1929

Syn. to A. loricatus ( Piersig, 1896) : Lundblad, 1956, Schwoerbel, 1957

Type series: Missing. Locus typicus: Szklenófürdö, Wilkensbach, 15.VI.27, 1 ♂; collecting site of the first female described ( Szalay, 1935b): stream of the Goldbrunner Tal near Körmöcbánya (Kom. Bars ) coll. E. Dudich 12.VIII.1933 .

Material examined: SMF 4996 Atracides barsiensis (Szalay) ♂ ♀; Jugoslavien Gospic¢ 29.8.1934 Quelle Viets leg. 4996. State of conservation: good, dorsal skin damaged, ♂ Gsk and chelicerae missing, ♀ left I-L damaged, III/IV- L missing .

Description. Male (original description): idiosoma L/W 475/375 Mm, integument striated; dorsalia and ventralia well developed as sclerite plates, glandularia surrounded by extended sclerite rings with irregular margin, Dgl-3 fused laterally to the platelet formed by postoc and D-1, Dgl-4 embedded in the plate of D-4; coxal field total L 267, maximum W of Cx-4 333, Cx-4 caudally, and particularly laterally with extended secondary sclerotization; I-L-5 dL 108, HB 41, S-1 67, S-2 50, I-L-6 dL 83 Mm, dL ratio I-L-5/6 1.30; genital field L/W 112/125 Mm, anterior margin straight, posterior margin slightly incised; excretory pore unsclerotized, Vgl-1 fused to Vgl-2; palp measurements, P-1–5, L/H 17/25, 50/33, 50/33, 83/28, 33/12, total L 233 Mm, ventral margin of P-4 divided by the insertion of ventral hairs in three sectors equal in L, sword seta inserted in the middle between these two hairs.

Male ( SMF 4996): idiosoma L/W 410/290 Mm, integument striated (11/10 Mm) coxal field L 220, Cx-3 W 238 Mm, slender, mediocaudal margin Cx-1 tongueshaped, apodemes of C-2 strong, forming an obtuse angle; I-L-5 ventral and dorsal margins diverging, dL 103, ventral L 84, HA–C 32, 35, 37 Mm (low difference HA/B due to ventral seta inserted far distally) S-1/2 L 48/42, I-L-6 L 77, HA–C 22, 21, 21 Mm, ratio dL I-L-5/6 1.34; ventralia small but clearly visible as sclerotized dots; genital field L 94, W 103 Mm, with anterior incision filled with secondary sclerotization, anterior margin of secondary sclerite straight, Ac-3 caudally extending far over the level of the postgen, external margin of genital field between Ac-2 and Ac- 3 slightly concave, excretory pore unsclerotized, Vgl-1 fused to Vgl-2; palp measurements, P-1–5 L/H 23/19, 51/37, 52/30, 79/24, 25/10, total L 230 Mm, with slightly protruding ventrodistal edge of P-2.

Female ( Szalay, 1935b): idiosoma dL (without tips of Cx-1) 567, W 433 Mm; integument finely granulated, glandularia and sclerites as in males; coxal field L 283, maximum W 367 Mm; I-L-5 dL 142, HB 45, S-1/2 L 67/ 58, I-L-6 L 100, HB 25 Mm, dL ratio I-L-5/6 1.42; genital field L 175, W 167, gonopore L 117, genital plates L 100 Mm; genital plates with a narrow border of secondary sclerotization, pregenitale with strongly sclerotized posterior margin, but thin sclerotization anteriorly; gnathosoma L 100, chelicera total L 142, claw 58 Mm, palp measurements P-1–5, L/H 25/–, 67/ 50, 75/42, 100/28, 33/–, total L 300 Mm

Female ( SMF 4996): similar to male, but sclerites generally smaller, partly not fused, only narrow borders of secondary sclerotization; idiosoma L/W 383/ 256, coxal field 220, Cx-3 W 243 Mm, Cx-1 + 2 mL 81, lL 157, W 144 Mm; I-L-5 dL 113, vL 92, HA–C 33, 36, 37, S-1/2 L 55/52, I-L-6 L 83, HA–C 24, 22, 22 Mm, ratio dL I-L-5/6 1.36; genital field L 126, W 144 Mm; palp measurements P-1–5 L/H 23/20, 56/37, 63/31, 81/ 23, 29/9, total L 252 Mm, ventrodistal edge of P-2 not protruding, P-4 with lower density of dorsal hairs.

Discussion: In the original description, Szalay discussed only diagnostic differences between A. barsiensis and A. lacustris , a species with dorsal sclerotization at that time known only from a preliminary description. A. lacustris is extremely different, e.g. in shape of mouthparts and legs, and belongs to the subgenus Tympanomegapus . Only when he described the female did Szalay (1935b) become aware that A. barsiensis is similar to A. loricatus ; he noted differences in the general shape of the idiosoma (roundish in A. loricatus , more elliptical in A. barsiensis ) the terminal segment of I-L, and the genital organ (without explicating the character of differences he enumerated). From a comparison with Piersig’s table 46 (to which Szalay refers) one may deduce that he referred to the narrower pregenitale (surely due to the juvenile state of the specimen depicted by Piersig) but no morphological differences of I-L-6 become evident. With good reason, Szalay asked for a revisional redescription of A. loricatus . Lundblad (1956), who discussed the loricatus -like water mites without having seen Piersig’s types, proposed the concept of an A. loricatus very variable with regard to the extension of idiosoma sclerotization (including an excretory pore with or without sclerite ring); he treated A. barsiensis as a variety of A. loricatus , differing only in a slightly longer I-L-6. Schwoerbel (1957) came to the conclusion that A. barsiensis is probably a synonym of A. loricatus , a concept finally accepted also by Szalay (1970).

On the other hand, Láska (1960) proposed the following diagnostic characters, as compared with A. loricatus: Prefr not fused to the anterior platelets (made up by postoc, D-1 and Dgl-3); all sclerite platelets smaller; male genital field more slender, caudally deeply indented and with oval, not subtriangular Ac; in both sexes, excretory pore without sclerite ring. Numerous other authors followed this proposal and continued to use both names separately (for a complete list, see K. O. Viets (1987). Further detailed discussions of loricatus -like water mites were published by Bader (1975, 1994). His observations are however, devalued by the fact that his interpretation of the types of A. loricatus was wrong (for a discussion see under A. loricatus and A. placocallosus Bader, 1994 ).

My observations of the types of A. loricatus and numerous additional preparations of loricatus -like mites suggest that they cannot be considered conspecific. That conclusion notwithstanding, A. barsiensis is really a synonym of A. loricatus . The differentiation proposed by Láska was based on taxonomically useful characters, but what he interpreted as A. barsiensis is actually A. loricatus , while the specimens attributed by him to A. loricatus represent another taxon, discussed below (see A. brendle sp. nov.).

The specimens from the Tatra mountains ex coll. Láska used here for the redescription of A. loricatus agree closely with the original description of A. barsiensis . The specimens from Croatia ( SMF 4996) are notably smaller, but do not differ in proportions and general idiosoma and gnathosoma morphology.