Burmapsilocephala evocoa, 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 : 77-79

Burmapsilocephala evocoa , new species

Figures 26A–C , 58

DIAGNOSIS: Distinguished from B. cockerelli (fig. 26D) also in Burmese amber, by possession of 14 thoracic macrosetae (vs. 12) as follows: 1 pair of notopleural setae (vs. 2), 2 pairs supraalars (vs. 1), 2 pairs postalars (vs. 1); notopleural setae distinctly shorter than in cockerelli ; R 5 ending at wing tip (vs. posterior to it), crossvein r-m at middle of cell d (vs. in basal third); A 2 and anal lobe more developed (possibly sexually dimorphic).

DESCRIPTION: Based on male. A slender, delicate, gracile fly with long, slender legs and abdomen. Body length 4.38 mm; thorax length 1.00 mm; abdomen length 2.87 mm; wing length ca. 2.90 mm; hind leg length 4.57 mm. Head: Dorsal surface flattened, broad. Eyes completely bare (no interfacetal setulae), holoptic in male, occupying most of head dorsally, frontally, laterally; medial margins of eyes meeting from ocellar triangle to just above bases of antennae, small portion of frons exposed; anteromedian margins of eyes slightly emarginate around bases of antennae; facets on dorsal surfaces ca. 2× diameter of ventral and lateralmost facets. Ocelli on small, low tubercle on posterodorsal margin of head capsule, with several stiff setulae in triangle. Face, including clypeus, deeply recessed, clypeus not visible. Antenna: Basal three segments stout, approximately equal in length; scape short, cylindrical; pedicel scoop shaped (longer setulae ventrally). Basal flagellomere asymmetrically drop shaped, attached dorsally to ventral apex of scape. Terminal article of antenna aristalike; long, flagellate, with short pubescence, length of article approximately equal to length of head. Occiput behind posterior margin of eyes with fringe of long, stiff, very fine setae. Mouthparts: Proboscis short, slightly flattened laterally, only labellum visible beyond oral margin; palp and number of pseudotracheae not visible. Thorax: Virtually bare of setulae, with only very sparse setulae on scutum and coxae. Bristlelike macrosetae as follows: 1 pair scutellars (apical), 1 postpronotal; 1 notopleural; 2 supraalars, 2 postalars. Scutum slightly arched, dorsum of scutellum slightly below that of scutum, scutellum small, no proscutellum present. Tranverse suture short, S-shaped, fully lateral. Wing: Slender, middle portion of wing obscured due to preservation and folding. Tip of Sc reaching nearly to middle of wing; tip of R 1 slightly beyond middle of wing. R 1 and R 2+3 very straight, nearly parallel; R 4 -R 5 forked, base of fork slightly distal to level of apex of cell d; R 4 slightly sinuous, tip of R 5 ending at apex of wing. Crossvein rm at middle of cell d. Cell br significantly longer than cell bm. Cells m3 and cup present (CuA 1 + A 1 meeting before wing apex). A 2 well developed but apically evanescent; anal lobe well developed, alula and upper calypter not developed. Legs: Metacoxa with well-developed knob on posterior surface. All tibiae with dorsal and ventral longitudinal rows of short, erect macrosetae (lengths of setae approximately equal to width of tibia), as follows: protibia with 2 dorsal, 2 ventral setae; mesotibia with 3 dorsal, 5 ventral; metatibia with 8–10 dorsal, 5–6 ventral setae. Apices of tibiae with circlet of approximately 4 small setae. Tibial spurs absent. Leg segment lengths: tibia> femur> tarsomere 1> tarsomere 2> 3> 4 = 5. Tarsomeres 1–4 on all legs with circlets of minute setae. Pulvilli slender, slightly shorter than claw; empodium tiny, bristleform. Abdomen: Long, slender, nearly cylindrical. Eight tergites exposed; lateral margins of tergites and sternites meeting. Terminalia (male): Projected posteriad, not flexed dorsad or ventrad. Epandrium apparently widely divided into pair of flat, setose lobes dorsally. Pair of small, setose lobes between epandrium and gonocoxae, probably the cerci. Gonocoxae setose, entirely free from epandrium and hypandrium, longer than gonostyli; gonostyli with only microtrichia (no setae), slightly pointed apically, without teeth; gonocoxae and gonostyli apparently articulating in oblique plane. Aedeagus not visible.

TYPE: Holotype, male, AMNH Bu-SE2/4.

ETYMOLOGY: Taken directly from the name of the type genus of Evocoidae , to which this fossil seems related.

Figures

FIG. 26. Burmapsilocephala spp. (Apsilocephalidae) in Burmese amber. A–C. Burmapsilocephala evocoa, new species. D. B. cockerelli Gaimari and Mostovski (ex: Gaimari and Mostovski, 2000). A. Head, oblique frontal view. B. Male terminalia, oblique lateral view. C. Wing of B. evocoa (portion are not fully observable). Arrows indicate diagnostic venational differences. D. Wing of B. cockerelli. Panels A, B to same scale.

FIG. 58. Burmapsilocephala evocoa, new species (Apsilocephalidae), holotype AMNH Bu-SE2/4. A. Habitus, left lateral. B. Head and thorax, left lateral.