Lestremia deploegi, Nel & Prokop, 2006

Nel, André & Prokop, Jakub, 2006, New fossil gall midges from the earliest Eocene French amber (Insecta, Diptera, Cecidomyiidae), Geodiversitas 28 (1), pp. 37-54 : 41-43

Lestremia deploegi n. sp. ( Fig. 2 )

TYPE MATERIAL. — Holotype specimen PA 1842 2/3, paratype PA 1608 1/7.

ETYMOLOGY. — After our friend Gaël De Ploëg, collector of the type specimen.

DIAGNOSIS (MALE). — Flagellomeres with nodes and necks of nearly equal length, eyes meeting above by only one point; fourth palpal segment is 1.7 as long as the third palpal segment; male gonostylus simple, not divided into a large inner lobe and an apical lobe.

DESCRIPTION

Head 0.11 mm long, 0.13 mm wide, 0.33 mm high; eyes very broad; eye bridge incomplete with eyes meeting in only one point; two ocelli well developed just above the eyes; antenna 1.08 mm long, scape 0.05 mm long, 0.03 mm wide, pedicel 0.04 mm long, 0.02 mm wide, 14 long flagellomeres, of nearly the same sizes, all longer than wide (0.08 mm long, 0.03 mm wide), and with a distinct neck, nodes of flagellomeres slightly shorter than necks (ratio length of node/length of neck 1.7), last flagellomere 0.05 mm long; flagellomeres with three rows of setae, the two basal one being crenulate; digitate sensoria absent on flagellomeres; gena short; palpus very long, 0.17 mm long, with four visible long segments, with palpal segment 1 short and stout, distal three palpal segments elongate, palpal segment 2 0.05 mm long, palpal segment 3 0.05 mm long, palpal segment 4 0.07 mm long; presence of rather long setae on palpal segments 3 and 4.

Thorax 0.38 mm long, 0.36 mm high, 0.25 mm wide, longer than broad.

Wing 1.10 mm long, 0.53 mm wide, hyaline, with microtrichia and macrotrichia, especially in posterior part of wing and along posterior margin; veins of posterior part of wing nearly as strong as those of anterior part; Costa not ending at apex of R5 but continuing around wing, although the strong anterior portion of C ends up with R5; humeral vein present, 0.11 mm from wing base; subcostal vein incomplete, 0.37 mm long, not reaching wing margin; vein R1 short, reaching anterior wing margin 0.44 mm basal of apex of R5; vein Rs emerging from R close to apex of R1 (0.42 mm); cross-vein r-m present but very short, 0.02 mm long; vein M1+2 never fused to Rs; sector of M1+2 basal of fork into M1 and M2 0.18 mm long, distinctly shorter than branches of fork; M1 complete and curved basally; M2 complete basally; vein m-m absent; vein M3+4 distinct, simple and nearly straight, basally vanishing close to M but basally replaced by a fold, very close to base of M; CuA simple, curved; CuP present, parallel to CuA and 0.38 mm long; A1 curved and long, complete basally and ending close to posterior wing margin; A2 not visible, probably absent.

Haltere with large knob, 0.08 mm wide and 0.1 mm long, and stem 0.09 mm long, bearing only two setae at its apex.

Legs slender, without scales; fore femur 0.50 mm long, tibia 0.45 mm long, tarsi 0.70 mm long; mid femur 0.63 mm long, tibia 0.50 mm long, tarsi 0.75 mm long; hind femur 0.65 mm long, tibia 0.58 mm long, tarsi 0.82 mm long; femora and tibiae not especially swollen; tibial spurs absent; tarsal claw with large basal lobe with small teeth; all legs with five tarsomeres, with tarsomere 1 longer than 2.

Abdomen (male) with eight segments before genitalia, 1.05 mm long, 0.38 mm wide, bearing numerous long setae; segment 8 unmodified; parameres not visible, hidden by wings; gonostylus simple, short and broad, curved, 0.21 mm long, 0.09 mm wide, bearing numerous curved setae.

DISCUSSION

For the same reason as Lestremia eocenica n. sp. above, L. deploegi n. sp. falls in the genus Lestremia . L. deploegi n. sp. differs from L. eocenica n. sp. in its simple gonostylus, and also the nodes of flagellomeres slightly shorter than the necks, instead of being distinctly longer. This character of L. deploegi n. sp. is also present in the recent Lestremia species and in the Baltic amber L. pinites ( Kieffer 1913; Jaschhof 1998). Also, the eyes of L. deploegi n. sp. meet dorsally at only one point, unlike those of L. eocenica n. sp. and in the recent Lestremia species in which the eye-bridge is three or four facets broad ( Edwards 1938a: 25). Nothing is known about the eye-bridge of L. pinites , but Meunier (1904) indicated that the male fourth palpal segment of this last species is 1.3 as long as its third palpal segment. In L. deploegi n. sp., the fourth palpal segment is 1.7 as long as the third palpal segment.

Tribe MICROMYINI Rondani, 1856

Figures

FIG. 2. — Lestremia deploegi n. sp., holotype (PA 1842 2/3), general habitus:A, drawing; B, photograph.Scale bars:A, 0.5 mm; B, 1 mm.