Chimeromyia burmitica Grimaldi & Cumming

Grimaldi, David A., Cumming, Jeffrey M. & Arillo, Antonio, 2009, Chimeromyiidae, a new family of Eremoneuran Diptera from the Cretaceous, Zootaxa 2078, pp. 34-54 : 36-39

Chimeromyia burmitica Grimaldi & Cumming , sp. n.

( Figs. 1–3 )

Diagnosis. Immediately distinguished from all other species in the family by the loss of vein R2+3; vein M very faint, anal lobe of wing highly reduced, CuA2 + CuP veins highly reduced to small spur at base of wing; male terminalia with glabrous, sclerotized epandrium; surstyli simple, base enlarged, apical half slender and digitiform. In Burmese amber.

Description. A minute fly, body length 1.1 mm. Body apparently yellowish, no apparent color patterns. HEAD: Eyes reddish, without interfacetal setulae, occupying most of lateral surface of head, no differentiation of facets. Two pairs ocellar setae, posterior pair slightly behind posterior ocelli, anterior ocellars slightly posterior to anterior ocellus; ocellar triangle not particularly tuberculate. No setae on frons. One pair of long inner vertical setae present, plus smaller postoculars. Antenna with pedicel cup-shaped, no visible setae; basal flagellomere setulose, lobe-like, with depression and possibly with inserted condyle on mesal surface; rest of flagellum aristate, having two small basal articles and a long, fine, setulose terminal article. Clypeus large, protrudent, apex with pair of thick, stiff setae. Palpus and labellum small; details not visible. THORAX: Mesoscutum with one row of acrostichal setulae; two long rows dorsocentrals flanking acrostichals (slightly larger than acrostichals); each postpronotal lobe with erect seta. Mesoscutellum with single pair of setae (apicals), slightly erect. Wing: Broadly rounded on apex, base narrow, with anal lobe lost.

Sc incomplete, apically evanescent; C ending at apex of R5; R1 short, apex reaching to midline of C; R2+3 lost; vein R4+5 forked with R4 widely divergent from R5, approximately 80° divergent from R5. Vein M very faint, basally and apically evanescent; M2 present, barely connected to M 1 in short basal fork; crossveins r-m and bm-cu nearly in line, with gap where M intersects. CuA1 basally sclerotized, portion apical to bm-cu is faint. CuA2 + CuP highly reduced to small, spur-like vein at base of wing. Legs: Simple, with no distinctive setation or spines, save for row of ca. 6 longer, thin, stiff setae on ventral surface of fore femur. ABDOMEN: fairly long and narrow, tapered apicad, with eight tergites fully visible. Male terminalia: Epandrium short, seemingly heavily sclerotized (darker than rest of sclerites), glabrous save for row of 4 stiff setulae on posterior surface; posteroventral margin with slight notch. Cerci fused medially, long and narrow in lateral view, extended slightly beyond apex of surstyli. Surstyli apparently articulated with epandrium, with basal half broad and apical half slender and digitiform; apparently bare of setulae. Only apex of phallus visible, extended to three-quarters the length of surstyli. Postgonites present, with small dorsal lobe bearing apical seta, several other stiff setae. Hypandrium setulose, simple and lobe-like. Female terminalia (best seen in AMNH Bu298, where abdomen is cleared, but spermathecal capsules not visible): Cerci lost or not apparent, sternite VIII subtriangular, minute triangular sclerite on ventral surface of apex; no acanthophorite spines.

Types. All types in amber from northern Myanmar, Kachin state, near the village of Tanai (ca. 100 km NW of the Mytchkina), coll. 1999 by Leeward Capital Corp. Holotype, male, AMNH Bu352; Paratypes, two females, AMNH Bu298, AMNH Bu504. The holotype is particularly well preserved, though the wings are folded (reconstructed in Fig. 2 B).

Etymology. Taken directly from the former name of the Republic of Myanmar.

Figures

FIGURE 1. Chimeromyia burmitica, n. sp., in Burmese amber. A. Holotype, AMNH Bu 352, left habitus. For detail of male terminalia see fig. 3 B B. Paratype male, AMNH Bu 504, oblique right lateral habitus. C. Paratype female, AMNH 298, right habitus, for detail of terminalia see fig. 3 C. The abdomen is cleared, but spermathecae are not visible.

FIGURE 2. Chimeromyia burmitica, n. sp., in Burmese amber. A. Wing of paratype, AMNH Bu- 170. B. Left habitus of holotype male, AMNH Bu 352, slightly reconstructed to show left wing (which is folded over the abdomen in specimen). C. Dorsal habitus exclusive of wings, AMNH Bu 352.

FIGURE 3. Chimeromyia burmitica, n. sp. A. Head, paratype AMNH Bu 504, oblique dorsal view. Slightly reconstructed (eyes collapsed in specimen). B. Male terminalia of holotype, AMNH Bu 352, left lateral view. C. Female terminalia of paratype, AMNH Bu 298.