Orthocladiinae, Edwards, 1929

Published, First, 2007, Chironomid midges from early Eocene amber of France (Diptera: Chironomidae), Zootaxa 1404, pp. 1-66: 41-42

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Orthocladiinae   genus and species C

Description: Head 0.3 mm long, deformed; ocelli absent; antenna 0.52 mm long, much longer than head, distinctly hairy, with 13 flagellomeres covered with long setae (shortest 0.008 mm long, longest 0.31 mm long), pedicel broad and short, rounded, 13 th flagellomere 0.24 mm long, without subapical setae; eye bare, with strong parallel­sided dorsomedial extension; mouthparts lacking functional mandibles; 5 palpomeres with setae; 3 postocular setae visible, frontal and inner and outer vertical setae not visible. Thorax 0.52 mm long, 0.24 mm wide, 0.44 mm high; postnotum bare with distinct median groove; 4 setae on surface of scutellum; no scutal tubercle; no acrostichals, dorsocentrals uniserial; scutum without median longitudinal groove; about 4 prealar and 1 supraalar setae; epimeron II and preepisternum bare. Wing macropterous, more than 0.7 mm long, hyaline, wing membrane covered with few macrotrichia; anal vein An 2 absent; radius with 2 branches R 1 and R 4+5, R 2+3 absent; only M 1+2 and M 3+4 present; cross­vein MCu absent; squama bare. Halter 0.15 mm long. Fore femur 0.38 mm long, tibia 0.46 mm long, tarsus 0.62 mm long; mid femur 0.36 mm long, tibia 0.36 mm long, tarsus 0.58 mm long; hind femur 0.24 mm long, tibia 0.4 mm long, tarsus 0.5 mm long; ta4 of all legs cylindrical, not cordiform; fore tibia with 1 long spur, mid and hind tibiae with 2 long spurs, hind tibial comb well developed. Abdomen 0.76 mm long; gonostylus simple, elongate, 0.04 mm long and 0.01 mm wide, without strong apical megasetae, shorter than gonocoxite; gonocoxite 0.07 mm long, 0.03 mm wide at base, with few long setae on outer surface; anal point narrow and elongate, 0.05 mm long and 0.03 mm wide at base, inferior volsella visible.

Discussion: In the key to Holarctic orthocladiine genera of Cranston et al. (1989), this orthocladiine falls in couplet 35 because of the following characters: wing well developed; without thick clavus; scutum without median longitudinal groove; eye bare; wing covered with few macrotrichia; gonostylus simple; anal point distinct; and eye with strong dorsomedial extension. The apex of the wing cannot be seen to determine if the costa is produced. Thus, we cannot precisely determine the affinities of this fossil, but it is different from those already described from the Oise amber.

Material: Specimen PA 461, (male).