Cretasolva burmitica, Grimaldi, 2016

Grimaldi, David A., 2016, Diverse Orthorrhaphan Flies (Insecta: Diptera: Brachycera) In Amber From The Cretaceous Of Myanmar: Brachycera In Cretaceous Amber, Part Vii David A. Grimaldi, Bulletin of the American Museum of Natural History 2016 (408), pp. 1-132 : 12-14

Cretasolva burmitica , new species

Figures 3 , 34

DIAGNOSIS: As for genus, by monotypy.

DESCRIPTION: Based on unique female. Slen- der bodied with slender wings, legs of moderate length. Body length (excluding antennae, including cerci) 4.69 m; thorax length 1.66 mm; wing length 3.60 mm; abdomen length (including cerci) 2.50 mm. Head: Slightly broader than thorax, occiput slightly concave. Frons relatively broad, width slightly greater than distance between outside margins of lateral ocelli. Face concave (clypeus not observable). Eye: Relatively large, occupying most of head surface in lateral, frontal, and dorsal views. Margins with frons parallel. Eye completely bare, facets not differentiated. Ocelli slightly raised above surface of frons. Antenna: Submoniliform, with 8 flagellomeres evenly tapered from broad basal one to narrow apical flagellomere, apical one with minute style. Flagellomere lengths: 8> 7> 6 = 1> 2–5. Scape and pedicel small; antennal sockets very close, situated in ventral half of frons. Mouthparts: Palps directed forward; 2-segmented, basal palpomere slender; apical one oval, nearly twice width of basal palpomere. Proboscis short, only labellum exposed; labellum large, fleshy, laterally flattened. Thorax: Dorsum of scutum, scutellum, portion of anepisternum with dense, very fine, setigerous punctation, denser on scutellum; no macrosetae or long pilosity. Transverse suture short, mostly lateral (pleural), with faint impression dorsolaterally. Scutellum narrow in dorsal view, longer than wide, without spines; small, short but distinct proscutellum present. Pleural sutures not easily observed in unique specimen; pleura large oblique (vs. vertical). Wing: Long, slender, W/L 0.30, veins well developed, most are well sclerotized, lightest ones are R 2+3 and base of M (latter faint, not sclerotized). Minute setulae on R veins (except R 2+3) and M veins (except for stem), none on Cu veins. Vein C ends at apex of M 1. No pterostigma. Sc complete, ca. 0.5× wing length; R 1 0.55× wing length, close and parallel to Sc; Rs and R 2+3 short, parallel to R 1; Rs without thickened node or weak area; fork of R 4 -R 5 asymmetrical, R 4 0.66× length of R 5. Crossvein r-m close to base of cell d, M veins connected to apex of cell d; M 1, M 2 parallel; cell m long, slender, nearly reaching to wing margin (M 3 +CuA 1 spur very short); crossvein m-cu present. Cell d long and narrow, W/L 0.3; cells br and bm of equal length. Vein A 1 very long, apex reaching to midlength of wing, cell cup closed. Vein A 2 short; anal lobe and alula present but small. Legs: Robust, of moderate length. Coxae robust, meso- and metacoxae meeting, distant from procoxa. Relative lengths of leg segments: Pro- and mesofemur> tibiae> basitarsomere> combined lengths tarsomeres 2–5. Metatibia> femur> basitarsomere> combined lengths tarsomeres 2–5. Tibial spurs 0-2-2; spurs long and thin, lengths ca. 1.5× apical width of tibiae. No tubercles on ventral surface of hind femur. Pretarsus with well-developed simple claws; pulvilli small, ca 0.5× length of claw; empodium pulvilliform, short and broad. Abdomen: Only slightly longer than thorax, thickness and width tapered to narrow apex. Seven tergites visible, basal 2 tergites fully sclero- tized (no median membranous areas); tergite 1 narrow in dorsal view, width of its posterior margin ca. 0.5× that of tergite 2; tergite 2 large, nearly twice the length of tergite 3; broadest tergites t2, t3. Cerci (female) long, slender, 2-segmented, length approximately equal to length of segments 6+7, basal cercomere slightly longer than apical one; t10 small, lying between bases. Tergites 2–4 with shallow transverse sulci (possibly on t1 and t5 but not fully visible).

TYPE: Holotype, female, AMNH Bu-SE05.

ETYMOLOGY: Derived from English burmite, another name for Burmese amber, and Latinized.

COMMENTS: Specimen is in a small, irregular piece 4 × 5 × 6 mm, with the sides closely surrounding the specimen, providing most views. The fly is complete, but it lies on a weathered internal flow; body of the fly (but not the wings) has a thin, reddish covering over the exocuticle, which, along with some fine fractures, obscures some details. This reddish layer indicates initial stages of pyritization. The section with the fly was trimmed from a cabochen that also contains two small moths, one adult Cicadellidae (Auchenorrhyncha) , and a spider.

Figures

FIG. 3. Cretasolva burmitica, new genus and species (Xylomyidae), AMNH Bu-SE05, holotype. A. Wing. B, C. Apices of meso- and metatibia, respectively, showing spurs. D. Head, lateral view, with detail of antennal apex.

FIG. 34. Cretosolva burmitica, new genus and species, holotype AMNH Bu-SE005 A. Right habitus. B. Right wing.