Litocladius, Humberto F. Mendes, Trond Andersen & Ole A. Saether, 2004

Humberto F. Mendes, Trond Andersen & Ole A. Saether, 2004, A review of Antillocladius Saether, 1981; Compterosmittia Saether, 1981 and Litocladius new genus (Chironomidae, Orthocladiinae), Zootaxa 594, pp. 1-82 : 72-74

Litocladius new genus

Type species

Litocladius mateusi new species.

Diagnostic characters

The imagines can be separated from other orthoclad genera by having scalpellate acrostichals, long virga with lateral lamellae, short costal extension, setae on squama and long anal point with lateral setae . The male may have a few setae apically on the wing, while the female has numerous setae on the wing membrane. The pupa can be separated from that of Gymnometriocnemus Goetghebuer by lacking frontal setae and by having all thoracic setae reduced. The larva is not known.

Etymology

From Greek, litos, meaning plain, simple, referring both to the reduced pupa and the “normal “ inferior volsella; and – cladius, a common ending among orthoclads.

Generic diagnosis

Imago

Small to medium sized species, wing length about 1.4 mm.

Female antenna with 5 flagellomeres. Male antenna with 13 flagellomeres, groove beginning at flagellomere 3, sensilla chaetica on flagellomeres 2, 3 and 13. Male antennal ratio about 1.5.

Head. Eye naked, without dorsomedial extension. Temporal setae divided into weak inner verticals, stronger outer verticals, postorbitals absent or few. Third palpomere with about 3 sensilla clavata apically, longest about 20 µm long.

Thorax. Antepronotum well developed, lobes meeting medially along short suture. Acrostichals short, anterior few simple, posterior scalpellate, beginning close to antepronotum, prealars uniserial; supraalar 0–1; scutellars uniserial.

Wing. Anal lobe developed. Costa at most moderately extended. R2+3 running and ending midway between R1 and R4+5; R4+5 ending slightly distal to M3+4; FCu far distal to RM; Cu1 straight; An ending proximal to FCu. Veins bare in male. Membrane with apical setae in female; male with or without few weak setae apically in cell r4+5, Squama setose.

Legs. Pseudospurs, sensilla chaetica and pulvilli lacking. Comb and tibial spurs normal.

Abdomen. Tergites with irregularly arranged setae .

Hypopygium. Anal point long, pointed, with few lateral setae , without microtrichia near apex. Phallapodeme and aedeagal lobe well developed. Anterior margin of sternapodeme weakly arcuate, oral projections moderately developed. Virga consisting of 2 long, strong spines with lateral lamellae. Inferior volsella with anterior dorsal triangular part and a more rounded ventral, posterior part.

Gonostylus without heel; crista dorsalis rounded and well developed. Megaseta normal.

Female genitalia. Gonocoxapodemes curved and meeting anterior of vagina. Gonocoxite well developed, with a few long and some short setae . Tergite IX divided. Gonapophysis IX apparently with large ventrolateral lobe covering apodeme lobe, and narrow, line­like dorsomesal lobe. Labia relatively large, pointed. Cerci small. Seminal capsules small to medium­sized, circular, with triangular neck. Spermathecal ducts not observable on available specimen.

Pupa

Small, total length 2.3 mm.

Cephalothorax. Frontal setae absent. Frontal apotome smooth. Antennal sheath with basal pearl row. Ocular field with 2 reduced postorbitals. Thoracic horn absent. Three weak precorneals situated in narrow triangle. Two weak antepronotals. Dorsocentrals very small, in two groups of two. Thorax and wing sheath smooth.

Abdomen. Tergite I–VIII covered with coarse shagreen except along anterior margin; tergite IX with strong shagreen except along posterior margin. Sternites I–IV bare; sternite V with median shagreen; sternites VI–VII with slightly more extensive median and lateral shagreen; sternite VIII with extensive shagreen; sternite IX with anterolateral shagreen. Tergite II without posterior hooklets. Tergites without posterior row of weak spines. Conjunctives bare. Pedes spurii A and B absent. Apophyses weak, nearly straight. Segment II –VIII with 2 weak, hair­like L setae . Anal lobe without macrosetae; male genital sac overreaching anal lobe.