Archaeognoriste primitiva, BLAGODEROV & GRIMALDI, 2004

BLAGODEROV, VLADIMIR & GRIMALDI, DAVID, 2004, Fossil Sciaroidea (Diptera) in Cretaceous Ambers, Exclusive of Cecidomyiidae, Sciaridae, and Keroplatidae, American Museum Novitates 3433 (1), pp. 1-76 : 12

Archaeognoriste primitiva , new species

Figures 7, 8 , Plate 1D

DIAGNOSIS: As for genus.

DESCRIPTION: Body length = 1.58 mm (ho­

lotype)/ 1.47–1.61 mm (paratypes); wing length = 0.98/ 0.95–1.10 mm. Head: Posterior surface flat, with scattered setulae. Frons membranous. Eyes large, hairy. Ocelli not seen. Scape and pedicel slightly wider than flagellomeres, subconical. Flagellum 14­segmented, flagellomeres cylindrical, width about equal to length. Palpi 3­segmented, segments cylindrical. Penultimate segment about 0.75Χ the length of apical one and 2Χ the length of antepenultimate. Thorax: Scutum irregularly covered with short setae and bearing long lateral and acrostichal setae. Scutellum with two pairs of long setae and several short ones. Antepronotum and preepisternum with 6–8 long setae. Anepisternal suture declines posteriorly. Anepisternum with small cleft. Mediotergite setose, laterotergites bare. Dorsal edge of mesepimeron protruding toward laterotergite. Metepisternum with deep cleft, height more than width. Wing membrane without macrotrichia. C not reaching wing tip, ends one­fourth distance between tips of R 5 and M 1. All veins bear setae. Sc very short, free. R 1 about 0.6Χ the length of wing. RS base distinct, at the level of Sc tip. Crossvein r­m fused with tb, oblique. Stem of M and base of M 1 and M 2 fork absent. M 3+4 base very weak. M and CuA veins weak. Legs: Fore coxae densely setose, mid and hind coxae with setae on apical half, all coxae about equal in size. Tibial and tarsal trichia not in rows. Abdomen setose, with exception of 1st and 2nd sternites. Seventh sternite short, 8th small and retractable. Ninth tergite small, rectangular, with well­developed, short, one­segmented cerci apically. Gonocoxites straight. Gonostyli saberlike, thinner to apex, with one apical and one very long curved basal processes.

MATERIAL: Holotype AMNH Bu­1539, male; paratypes AMNH Bu­412a and Bu­ 412b, 2 males in the same piece, Bu­485, Bu­ 693, males. Myanmar: Katchin , from amber mines near Myitkyina.

ETYMOLOGY: The species epithet is from Latin primitivus meaning ‘‘the first or earliest of its kind’’ and is a reference to the basal position of the species within Lygistorrhinidae .

COMMENTS: Venation of the species is almost identical to Palaeognoriste sp. ( Grimaldi and Blagoderov, 2001: figs. 5a, 6a), with bases of RS and r­m somewhat reduced and shifted proximally. Characters such as reduced palpi, membranous frons, the wing venation, simplified genitalic structure, and a large metepisternum (presumably plesiomorphic) with deep anteriodorsal cleft obviously refer the species to the Lygistorrhinidae , but compared to more derived species the new species has many plesiomorphies: presence of RS base and a distinct r­m, unmodified legs, and gonostyli with long processes.

Figures

Figs. 7–11. Archaeognoriste, n.gen. and Lebanognoriste, n.gen. 7. A. primitiva, n.sp., holotype AMNH Bu­1539 8. A. primitiva, male genitalia. 9. L. prima, n.sp. holotype AMNH JG268/1. 10. L. prima, male genitalia dorsally. 11. L. prima, male genitalia ventrally.