Eotrechus pilicaudatus, Duc, Tran Anh & Zettel, Herbert, 2006

Duc, Tran Anh & Zettel, Herbert, 2006, Notes on Eotrechus Kirkaldy, 1902 (Heteroptera: Gerridae), with descriptions of two new species, Zootaxa 1353, pp. 39-51 : 40-43

Eotrechus pilicaudatus sp.n.

( Figs. 1–8 )

Material examined. Holotype (apterous ɗ): INDIA (NE), Meghalaya, 3 km E Tura, 1150 m, 25°30'N 94°14'E, leg. L. Dembicky & P. Pacholatko, 18 Apr. 1999 ( NHMW).

Description of apterous male. Size: length 6.50 (from head to hind margin of 8th tergite), width 2.40.

Colour. Body mainly brown dorsally and pale yellowish ventrally; dorsum with scattered silvery or golden pubescence; venter also with silvery scattered pubescence. Head with median yellowish stripe, anterolateral areas and hind margin yellowish; antennae dark brown; pronotum with median longitudinal yellow stripe and two U­shaped yellow markings (sub­)laterally; yellowish markings on mesonotum almost as wide as brown markings; metanotum and abdominal terga mostly dark brown; pro­, meso­, metasternopleura dark brown, with dense silvery and reflective pubescence; legs: fore and mid coxae and trochanters yellowish; hind coxa and trochanter more yellow than brown; fore femur and tibia yellow, mid and hind femora and tibiae brownish, all tarsi and claws brown.

Structural characteristics: Head width across eyes 1.53; interocular width 0.70; eye kidney­shaped on dorsal view, eye size 0.69. Antennae about 1.07x of body length (6.95: 6.50), lengths of segments 1–4: 2.33: 1.70: 1.04: 1.88; first segment with two black spinelike hairs apically. Pronotum broader than long, shorter than median head length (1.00: 1.50). Lengths of mesosternum and metasternum: 2.20 and 0.55. Lengths of leg segments (femur: tibia: tarsal segment 1: tarsal segment 2) as follows, fore leg: 2.73: 2.40: 0.24: 0.43; mid leg: 8.10: 7.10: 0.60: 0.74; hind leg: 8.20: 7.50: 0.63: 0.79. Fore femur ( Fig. 1 ) incrassate at base and tapering toward apex, length about 4.27x maximum width (2.73: 0.64), ventral surface without spinelike hairs; fore tibia slightly S­curved, with some long black spinelike hairs apically. Mid and hind femora slender and longer than body. Mid and hind trochanters with some black spines, mid and hind femora with numerous black spines; those spines shorter and stouter on mid trochanter and ventral surface of mid femur ( Figs. 2–3 ). Claws stout, lengths of fore, mid, hind claws 0.20: 0.26: 0.26. Abdomen relatively short, venter slightly depressed from segment 3–7, length of abdominal venter from sternum 2 to sternum 7: 1.09; sternum 7 about 2.08x length of two preceding sterna combined (0.50: 0.24), posterior margin moderately emarginated: width of median notch equal to length of sternum 7 (0.50), depth less than one­third length of sternum 7 (0.16: 0.50), margin with long, soft, brown hairs ( Fig. 4 ). Segment 8 relatively wide, with almost straight posteroventral margin ( Fig. 4 ). Genital segments relatively large: proctiger slightly smaller than pygophore, with paired long, bristlelike, black hair tufts on slightly produced distolateral margins ( Fig. 5 ); pygophore broad, sub­oval, with paired long, bristle­like, black hair tufts lateroventrally, hind margin with paired, small, pointed, black processes consisting of tightly packed thick setae ( Figs. 6–8 );. Paramere very short, blunt, with some long soft hairs on apex.

Apterous female, macropterous female, and macropterous male: unknown.

Etymology. The species epithet is an adjective derived from the Latin pilus (= hair) and cauda (= tail or genitalia) and refers to the dense, long hair­tufts on the genitalia of the male.

Remarks. This new species resembles Eotrechus pingae Andersen, 1998 and Eotrechus hygropetricus Andersen, 1982 in having patches of long hairs laterally on the pygophore and the proctiger. However, it differs from E. pingae by the simple shape of the proctiger (in E. pingae , this is produced laterally), and from E. pingae and E. hygropetricus by the simple fore femur, without basal tubercle and without stout hairs. Eotrechus pilicaudatus is distinguished from other described species of Eotrechus by the following combination of characters: broad yellow markings on head, pro­ and mesonotum; relative length of mesosternum, about 4.0x metasternum (greater than the maximum ratio 3.6x provided by Andersen (1982) in his generic description); fore femur incrassate at base and tapering toward apex, without spinelike hairs; sternum 7 of male much longer than preceding two sterna combined (in generic description by Andersen (1982), sternum 7 only subequal to or shorter than sterna 5 and 6 combined); pygophore and proctiger with dense bundles of bristlelike hairs; posterolateral processes of pygophore very short. See also remarks for E. luaae sp.n.

So far, this is the fifth Eotrechus species recorded from India (previous records are E. brevipes Andersen, 1982 from West Bengal and Sikkim, E. longipes Andersen, 1982 from Uttar Pradesh and West Bengal, E. terrestris from Sikkim, and E. kalidasa from Meghalaya).

Figures

FIGURES 1 – 8. Eotrechus pilicaudatus sp. n. (male): (1) right fore leg; (2) abdominal venter (genitalia excluded); (3) mid trochanter and part of femur; (4) hind trochanter and part of femur; (5) proctiger (dorsal); (6) pygophore, dorsal view; (7) same, ventral view; (8) same, lateral view.