Xenochironomus trochanteratus (Thompson, 1869)

Fusari, Lívia Maria, Roque, Fabio De Oliveira & Hamada, Neusa, 2013, Review of Xenochironomus Kieffer, 1921 (Diptera: Chironomidae) with description of six new species, Zootaxa 3646 (2), pp. 101-126 : 107-109

Xenochironomus trochanteratus (Thompson, 1869)

Chironomus trochanteratus Thompson 1869: 445 .

Chironomus (Xenochironomus) trochanteratus (Thompson, 1869) ; Edwards 1929b: 7.

Material examined. Holotype: PHILIPPINES, Manilla, 1 male (SMNH).

Diagnosis. Xenochironomus trochanteratus can be separated from other species in the genus by the following characteristics: male, frontal tubercles present, sternite VI with 14 large dark setae; superior volsella short and large, with posterior region membranous; inferior volsella narrow with setae only on the dorsal region and externally directed; setae of inferior volsella and setae of the inner gonostylus plumose.

Description. Male (n = 1)

Color. Brownish. Femur and tibia dark brown and other segments light brown.

Wing length 2.06 mm, width 0.70 mm.

Head. In poor state of conservation. Flagellomeres and palpomeres lost. Temporals 16–19. Clypeus with 19 setae.

Thorax. In poor state of conservation; could not be observed.

Wing. VR 1.08. Brachiolum with 2 setae. R with 20 setae, R1 with 18 setae, R4+5 with 14 setae, remaining veins bare. Squama with 10 setae.

Legs. Length (µm) and proportions of leg segments as in Table 4 .

Abdomen. In poor state of conservation. Sternite VI with 14 long strong setae.

Hypopygium (Fig. 4 A–C). Laterosternite IX with 3 setae. Anal tergite with 11 setae in median region. Anal point 80 Μm long (bent ventrally); 47 Μm wide at the base, 22 Μm wide at the apex. Phallapodeme 133 Μm long; transverse sternapodeme 81 Μm long. Superior volsella 40 Μm long, 24 Μm wide at the base. Inferior volsella 158 Μm long, 18 Μm wide at the base and 25 Μm wide at the apex. Gonocoxite 209 Μm long. Gonostylus 198 Μm long. HR 1.05.

Female and immatures: unknown.

Comments. Although the specimen examined is not well preserved and mounted which does not allow the visualization of some structures (e.g. head, thorax, abdomen), X. trochanteratus can be recognized as belonging to the genus by having anal point large with T-shaped in cross-section, strongly curved ventrally; short superior volsella and with short setae; anal tergite with long setae; gonostylus with few long setae on disto-median region.

Tables

TABLE 4. Length (in µm) and proportions of legs of Xenochironomus trochanteratus (Thompson, 1869), male (n = 1).

	fe	ti	ta1	ta2	ta3	ta4	ta5	LR	BV	SV
P1	-	780	-	-	-	-	-	-	-	-
P2	900	820	440	220	160	80	60	0.54	4.15	3.91
P3	1040	1000	720	340	300	140	100	0.72	3.14	2.83