Calvopeza divergens, Grimaldi, 2018

Grimaldi, David A., 2018, Basal Cyclorrhapha In Amber From The Cretaceous And Tertiary (Insecta: Diptera), And Their Relationships: Brachycera In Cretaceous Amber Part Ix David A. Grimaldi, Bulletin of the American Museum of Natural History 2018 (423), pp. 1-97 : 1-97

Calvopeza divergens , new species

Figures 6 , 7 , 32

DIAGNOSIS: As for genus, by monotypy.

DESCRIPTION: (female only). Head: Broader than long, but slightly narrower than thorax. Eyes:

Bare, as preserved silvery, no emargination, large (occupying nearly entire lateral surface of head); no differentiation of facets. Frons without median furrow; with few, scattered fine setulae; no interfrontal, fronto-orbital, vertical, or ocellar setae; frons margins slighly divergent dorsad. Ocelli on low tubercle. Postocular setae reduced to a few fine setulae. Oral margin slightly concave; face flat, vibrissa and genal setae absent. Antenna: Scape small; pedicel ringlike, with distal rim of fine setulae, apex short, conical; arista apical; basal flagellomere ovoid; two minute basal aristomeres present, basalmost one smaller; apical aristomere bare, hardly longer than rest of antenna. Mouthparts: Clypeus short, much broader than long; palp large, oblong, flat, light, without setae (with just setulae and microtrichia); labellum well developed, laterally flattened when closed, with fine setulae on ventral surface.

Thorax: Scutum strongly arched, neck positioned low (slightly below level of scutellum); transverse suture short, restricted to vertical-lateral portion of scutum. Acrostichals extremely fine, short, in 2–3 irregular short rows; no thoracic macrosetae (e.g., dorsocentrals, supraalars, postalars, notopleurals, scutellars). Anepisternum relatively large, katepisternum small; prescutellum absent; thorax deep in lateral view; scutellum relatively small, roughly triangular in dorsal view.

Wing: Entirely clear (no tinting, even between Sc and R 1); pterostigma absent; membrane with fine microtrichia except in cells cup, br and base of bm. Vein C with fine setulae only, lacking thick spinules; C terminates at apex of M 1; Sc and R 1 long, closely adjacent. R veins without setulae or spinules, more sclerotized than other veins. Cell rm narrow, long, bm shorter than cup; crossvein br-m very short; dm-cu distant from wing margin by 3.5× its length (cell dm short); cup large, CuA 2 slightly arched, A 2 spectral. Anal lobe well developed, alula small. Legs: Very slen- der; coxae relatively short; metafemur slightly longer than pro- and mesofemur; bare except for dark bifid scales on tarsi and portions of tibiae, long row of extremely fine setae on dorsum of profemur (lengths about equal to femur width). Dark, bifid scales: row on lateral edge of pro- and mesotibia, plus encircling apex of tibia; 2–3 irregular rows on metatibia; on ventral surface of pro- and mesotarsomeres 1–4. Metatarsus slightly inflated and flattened laterally, tarsomere 2 shortest, tarsomere 3 longest, with 2 ventral rows of bifid setae.

Abdomen: Relatively short, stout; eight tergites visible, 2–4 largest ones; pleural membrane extensive (tergites and sternites not meeting laterally); tergites completely bare of setae or setulae; sternites small, subcircular to almost square, each extensively isolated by membrane, 7 visible.

Female Terminalia: Cercus 1-segmented, digitiform, setulose, hypoproct well developed (~ 0.5× length of cercus).

SPECIMENS EXAMINED: Holotype, female, AMNH BuSE-8. Paratypes JZC Bu212 (female), AMNH Bu-1510. All in Burmese amber. All are completely intact, though the holotype is particularly well preserved.

ETYMOLOGY: The species name refers to the widely divergent M veins.

Figures

FIG. 6. Calvopeza divergens, n. gen., n. sp. (Platypezidae), female holotype, AMNH Bu-SE8, in Burmese amber. A. Right lateral habitus. B. Frontal view of head. C. Lateral view of head. D. Wing. E. Mesotibiae and tarsi.

FIG. 7. Calvopeza divergens (Platypezidae), female paratypes in Burmese amber. A. JZC-Bu212, Dorsolateral habitus. B. Detail of head. C. Metatibiae and tarsi. D. AMNH Bu-1510.

FIG. 32. Calvopeza divergens, n. gen., n. sp. (Platypezidae), in Burmese amber. A, C, D, F. Female holotype, AMNH Bu-SE8. B, E. Female paratype, JZC Bu-212. A. Wing. B. Antenna. C, D. Hind leg, lateral and mesal, respectively. E. Mid leg, mesal. F. Thorax, lateral.