Maderomegapus, Lundblad, 1941

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 : 348-350

SUBGENUS MADEROMEGAPUS (LUNDBLAD, 1941)

Diagnosis: Integument lineated, muscle attachments unsclerotized; Cx-1 + 2 with truncated posterior margin and well developed, laterally directed apodemes of Cx-2; I-L-5 subrectangular, with more than one ventral seta at the centre of the segment, narrow setal interspace, strong, blunt I-L-6 with subparallel dorsal and ventral margin, weakly curved; genital field triacetabulate, excretory pore sclerotized, Vgl-1 separate from Vgl-2; palp with ventral projection on P- 2 in both sexes and sword seta P-4 inserted between ventral hair insertions; secondary sexual characters in the shape of I-III-L, P-2 and P-4.

Males: I- and II-L-3/4 inflated and densely covered by long hairs, also III-L with thickened central segments; genital field anteriorly with a pit embraced by a horseshoe-shaped sclerite collar on a medial projection, medial setae restricted to the level of Ac-1, lateral setae at regular distances from the posterolateral edge of Ac-1 until the caudal margin; mediocaudal margin weakly indented; P-2 with ventral projection strongly protruding, truncated, with irregular surface, P-4 thickened, ventral margin 1: 1: 1, sword seta strong, with a shallow longitudinal groove.

Females: I-L-3/4 thickened, but without particular setation, genital field with longish genital plates, P-2 projection much less projecting, and P-4 more slender than in males.

Discussion: For discussion of the significance of various character states for the subgeneric division of Atractides see ‘Taxa above and below species level’, above. As Maderomegapus is a monotypic taxon, the diagnosis includes several characters without phylogenetic significance, but useful for the taxonomic recogniton of the only known species. Two characters found in males only, but highly distinctive, justify the taxon’s separate placement: the extreme modification of I-III-L, and the presence of a deep pit at the anterior margin of the genital plate.

ATRACTIDES HYSTRICIPES (LUNDBLAD, 1941)

( FIG. 94A–H )

Maderomegapus hystricipes Lundblad, 1941b

Type series: Holotype ♂ SMNH 2898 . Typ. Maderomegapus hystricipes Ldbl. ♂. Madeira. Wattenfall vid 25 Fontes. 25.7.1935, leg. O. Lundblad. State of conservation: dorsum/ventrum separate, genital skeleton preparated, both I- L, and left II-IV-L separate, gnathosoma in situ, both palps separate, laterally, chelicerae in situ; mounting fluid in good state . Paratype ♀ SMNH 2899 . Allotyp, labelled like holotype. State of conservation: dorsum/ventrum separate , one egg, both I-L, left II-L, right III/IV-L separate, gnathosoma and both palps separate, laterally, one chelicera missing, the other damaged; mounting fluid in good state.

Description:

General features dorsal integument: lineated; muscle attachments: smooth coxal field: medioposterior margin of Cx-1 + 2 truncated, no secondary sclerotization; suture line Cx-3 and - 4 in its medial part directed posteriorly such that medial margin of the Cx-3 + 4 plate is made up only by Cx-3 I-L: sexual dimorphism in shape and setation of I-L-3/4; I-L-5 with more than one ventral seta and setae S-1/2 strong, little distanced; I-L-6 with dorsal and ventral margins subparallel, equally curved excretory pore: sclerotized; Vgl-1: separate from Vgl-2 palp: P-2 with ventrodistal extension, P-4 1: 1: 1, sword seta between insertions of ventral hairs, sexual dimorphism in shape of P-2/4 and sword seta of P-4

Males

Holotype genital field: anterior margin medially projecting, embracing a central pit anteriorly from the gonopore, gonopore and Ac rather large, posterior margin weakly indented; genital setae: 42, one medial group on the level of Ac- 1, a further group regularly lined along the posteriolateral margin.

palp: projection of P-2 extended, truncate, with ir-regular surface, ventral margin P-4 with a basal concavity, at the insertion of ventral hairs (without denticles) convexly protruding, sword seta knife-like, distally flattened and with a longitudinal groove.

idiosoma L/W 616/426; glandularia –

coxal field L 325; Cx-3 W 336; Cx-1 + 2 mL 126, IL 243, W 270

I-L-5 dL 132, vL 103, dL/vL 1.28, HA-HC 36, 43, 47, dL/HB 3.07

S-1 L 65, L/ W 9.3, S-2 L 51, L/ W 5.7, interspace 8, L S-1/2 1.27

I-L-6 L 108, HA-HC 24, 22, 23, dL/HB 4.91; L I-L-5/6 1.22

genital field L/W 108/121, Ac-1–3 L 53, 45, 49

gnathosoma vL 153; chelicera –

Figures

Figure 94. Atractides hystricipes. A, D, G, H, holotype ♂ SMNH 2898; B, C, E, F, paratype ♀ SMNH 2899. A, ♂ I-L; B, ♀ I-L; C, ♀ palp, medial view; D, ♂ palp, medial view; E, ♀ Vgl-1/2 and excretory pore; F, ♀ genital field; G, ♂ coxal field; H, ♂ genital field. Scale bars = 100 µm.