Microtendipes eocenicus, Published, 2007

Published, First, 2007, Chironomid midges from early Eocene amber of France (Diptera: Chironomidae), Zootaxa 1404, pp. 1-66 : 53-55

Microtendipes eocenicus n. sp.

( Figs. 51 –53)

Etymology: This species is named for the Eocene age of the fossil.

Diagnosis: RM oblique to R 4+5; wing apically rounded; 13 flagellomeres; apex of fore tibia lacking spur; squama fringed; no patch of posteriorly directed setae on the apicomedial part of its fore femur; anal point apically spatulate; gonocoxites small.

Description: Head 0.6 mm long; ocelli absent; antenna 1.04 mm long, much longer than head, distinctly hairy, with 13 flagellomeres covered with long setae, pedicel broad and short, rounded, 13 th flagellomere very long; eye bare but deformed, with strong parallel­sided dorsomedial extension, with 6 rows of ommatidia at minimum width; mouthparts lacking functional mandibles; 5 palpomeres with numerous setae; clypeus with few dorsal setae; postocular, frontal, inner vertical, and outer vertical setae not visible. Thorax 1.02 mm long, 0.37 mm wide, 1.25 mm high; scutum with distinct longitudinal median groove; postnotum bare, with distinct longitudinal median groove; surface of scutellum with few long setae; scutal tubercle absent; prealar and supraalar setae not visible; anterior acrostichal setae not visible, few dorsocentrals and uniserial setae. Wing macropterous, apically rounded, 2.4 mm long, 0.62 mm wide, hyaline, without macrotrichia but with fine punctution; anal vein An 2 absent; radius with 3 branches R 1, R 2+3 and R, R 2+3 not divided into R 2 and R 3; costa ending at level of insertion of last branch of radius; only M 1+2 and M 3+4 present; cross­vein MCu absent; squama fringed. Halter 0.27 mm long. Fore femur 1.2 mm long, tibia 0.9 mm long, tarsus 3.1 mm long; mid femur 1.18 mm long, tibia 0.94 mm long, tarsus 1.4 mm long; hind femur 1.22 mm long, tibia 1.18 mm long, tarsus 1.88 mm long; fore tibia without spur or spine; hind tibial combs separate; mid and hind tibiae with 2 spurs, 1 on each comb; ta4 of all legs cylindrical, not cordiform; claw of all legs simple; pulvilli absent. Abdomen 2.95 mm long, 0.65 mm wide; gonostylus with long setae in outer surface and few short setae on inner surface, 0.18 mm long, 0.05 mm wide; delimited from gonocoxite, very short, 0.11 mm long, 0.02 mm wide, with long setae on outer surface; anal point narrow and elongate, apically spatulate, 0.15 mm long, 0.07 mm wide at base; inferior volsella elongate, apically rounded and with strong setae, 0.13 mm long; median volsella not visible, superior volsella sickle­shaped.

4+5

FIGURE 52. Microtendipes eocenicus n. sp., holotype PA 1683, photograph of male genitalia.

FIGURE 53. Microtendipes eocenicus n. sp., holotype PA 1683, drawing of male genitalia; a, ventral view; b, dorsal view (scale bar = 0.3 mm).

Discussion: This fossil is in the chironomine genus Microtendipes because of the following combination of characters (Cranston et al. 1989): RM oblique to R 4+5; wing apically rounded; 13 flagellomeres; apex of fore tibia lacking spur; and squama fringed. The only character of Microtendipes that is not present in Microtendipes eocenicus is the presence of a patch of posteriorly directed setae on the apicomedial part of its fore femur. This character justifies a specific (if not generic) separation from all extant species of Microtendipes .

Material: Holotype PA 1683 (male).