Prolipiniella magnifica, Published, 2007

Published, First, 2007, Chironomid midges from early Eocene amber of France (Diptera: Chironomidae), Zootaxa 1404, pp. 1-66 : 47-49

Prolipiniella magnifica n. sp.

( Figs. 43, 44)

Etymology: This species is named after the wonderful state of the type specimen.

Diagnosis: Small species, otherwise as described for the genus.

Description: Head 0.38 mm long; ocelli absent; antenna 0.7 mm long, much longer than head, distinctly hairy, with 10 flagellomeres covered with long setae (shortest 0.02 mm long, longest 0.38mm long) with apical nipple and strong setae, pedicel broad and short, rounded, 10 th flagellomere 0.44 mm long; eye bare but deformed, with strong parallel­sided dorsomedial extension, with 4 rows of ommatidia at minimum width; mouthparts lacking functional mandibles; 5 palpomeres with numerous setae; 3 postocular setae; frontal and inner vertical and outer vertical setae not visible. Thorax 0.58 mm long, 0.2 mm wide, 0.52 mm high; postnotum bare, with longitudinal median groove; surface of scutellum with long setae; scutal tubercle present; prealar and supraalar setae absent; acrostichal setae absent; dorsocentrals uniserial; preepisternum bare. Wing macropterous, more than 1.18 mm long, 0.34 mm wide, hyaline, without macrotrichia; anal vein An 2 absent; radius with 3 branches R 1, R 2+3 and R 4+5, R 2+3 not forked into R 2 and R 3; only M 1+2 and M 3+4 present; cross­vein MCu absent; squama bare. Halter 0.16 mm long. Fore femur 0.6 mm long, tibia 0.3 mm long, tarsus 1.6 mm long; mid femur 0.58 mm long, tibia 0.42 mm long, tarsus 0.68 mm long; hind femur 0.54 mm long, tibia 0.56 mm long, tarsus 0.94 mm long; fore tibia with scale rounded, without spur; median and hind tibial combs each with 1 spine; combs closely approximated but separated; ta4 of all legs cylindrical, not cordiform, pulvilli absent. Abdomen 1.2 mm long, 0.36 mm wide; no ventral setae on sternite VI; gonostylus with inner and outer long setae, 0.07 mm long, 0.03 mm wide; fused to gonocoxite 0.09 mm long, 0.01 mm wide; anal point narrow and rounded (0.05 mm wide at base, 0.09 mm long); inferior volsella well developed, elongate and cylindrical, 0.11 mm long, 0.01 mm wide, with setae on inner surface, not bowed dorsoventrally; median volsella absent; superior volsella with basal part bearing long setae and apically narrow and elongate, without setae, 0.05 mm long.

Discussion: This fossil falls in the Chironomini & Pseudochironomini based on the characters stated above (see Endochironomus eocenicus n. sp.). Prolipiniella n. gen. does not correspond to any of the described Holarctic genera because it has only 10 flagellomeres. It falls near couplet ‘29’ (group of genera of Chironomus ) in the key of Cranston et al. (1989), for the following reasons: antenna with less than 13 flagellomeres; fore tibia with scale rounded, without a spur; inferior volsella well developed, elongate and cylindrical, not bowed dorsoventrally; no ventral accessory setae on sternite VI; and superior volsella with basal part bearing long setae. Within this group of genera, Prolipiniella does not fit in the genus Einfeldia Kieffer, 1924 , because Prolipiniella has no acrostichals and its anal point is narrow. Baeotendipes Kieffer, 1913 , is excluded because it has acrostichals and its anal point is truncate. Chironomus Meigen, 1803 , is excluded because it has acrostichals. Lipiniella Shilova, 1961 , has no acrostichals, but Prolipiniella differs from it as follows: small species; antenna with 10 flagellomeres; and scutum overreaching antepronotum. Prolipiniella has no prealar or scutellar setae; the median and hind tibial combs each have only one spine, instead of two; and pulvilli are not visible.

In the key to Afrotropical genera of Freeman (1957), Prolipiniella would fall near the genus Paratendipes Kieffer, 1911 , because of the following characters: hind tibia with two spurs; no visible pulvilli; fore tibia without spur or spine at apex of scale; and squama bare. However, Paratendipes has 14 flagellomeres instead of 10, as in Prolipiniella , and the latter does not fit any of the Australian described genera of Chironomini and Pseudochironomini listed by Cranston (2000).

FIGURE 44. Prolipiniella magnifica n. gen., n. sp., holotype PA 9182, drawing of habitus (scale bar = 0.5 mm), drawing of male genitalia (scale bar = 0.1 mm).

Because there is no world revision of the genera of the Chironomini and Pseudochironomini and several genera need a complete revision ( Ashe 1983), a comparison of Prolipiniella with all recently described genera is difficult. Among the recent genera sufficiently known to be compared with Prolipiniella ( Ashe, 1983) , Yama Sublette & Martin, 1980 , has an apically forked anal point, male antenna with 12 flagellomeres, and acrostichals ( Sublette & Martin 1980). The enigmatic Tripelma Kieffer, 1913 , differs from Prolipiniella by its 12 flagellomeres, and shorter three­segmented palps ( Kieffer 1913). Aedokritus Roback, 1958 , and Brunieria Kieffer, 1921 (a dubious recent genus) have 13 flagellomeres ( Kieffer 1921, Roback 1958). Harrisius Freeman, 1959 , has 14 flagellomeres ( Freeman 1959). Megacentron Freeman, 1961 , Conochironomus Freeman, 1961 , Imparipecten Freeman, 1961 , Stictochironomus Kieffer, 1919 , Parvitergum Freeman, 1961 , and Paraborniella Freeman, 1961 , have 14 flagellomeres ( Freeman 1961).

Among the fossil Paleogene genera (listed by Evenhuis 1994), the Chinese Eocene Amberaspinus Evenhuis, 1994 (replacement name for Aspinus Hong, 1981 ) probably has 11 flagellomeres and very different male genital appendages ( Hong 1981). The other Chinese Eocene genus, Fushunitendipes Hong, 1981 , is poorly known, but seems to have fore tibia with a long apical spur and very different male genitalia. Bythomyia Zhang, 1989 , is also poorly known, but seems to have very short, nonplumose antennae, distinctly shorter than those of Prolipiniella and a male hypopigium rotated through 180 degrees ( Zhang 1989). The Baltic amber genus Jentzschiella Meunier, 1899 , is poorly described, without any known diagnostic character that could be used to compare it with our fossil ( Meunier 1899). Other Baltic amber genera of Meunier are even more poorly described.

Material: Holotype PA 9182, (male).