Chandleromyia anomala, 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

Chandleromyia anomala , new species

Figures 8 , 33

DIAGNOSIS: As for genus, by monotypy.

DESCRIPTION: (male only). Head: Large, broader than thorax. Eyes bare, large, holoptic for ~30 facets (virtually entire length of frons except short segment above antennae). Dorsal facets (~ 70% of eye) large, 2× diameter of ventral facets. Frontal margins of eyes emarginate around bases of antennae, margins slightly divergent ventral to this. Median furrow of frons, interfrontal, fronto-orbital setae (presence/ absence) not observable. Face entirely bare. Ocelli on tubercle, with pair of short posterior setae (length shorter than diameter of ocellus). Vertical setae absent; postoculars minute, except for short row of 4–5 short, thick seate on dorsal portion. Occiput with fine, short, scattered, light setae (lengths ca. equal to diameter of large eye facets); occipital setae do not extend to gena. Vibrissa, genal setae absent. Antenna: Scape small, barely exposed, apparently bare; pedicel small, conical, with apical circlet of setulae; arista terminal; basal flagellomere small, tapered, with incised portion mesally; two small basal aristomeres (lengths ~3× the diameter); apical aristomere long, fine, bare of any micropubescence.

Mouthparts: Oral margin squared; clypeus a broad triangle; labrum broad, apex pointed and sclerotized; labellar lobes deeply separated anteriorly, ~0.65× lobe length; palp very small.

Thorax: Scutum convexed but not arched, flatter anteriorly. Acrostichals completely absent, even minute ones. Only 1 pair of dorsocentrals present, short, prescutellar, no smaller, graded dorsocentrals present. Supraalar setae absent; 4–5 stout notopleural setae present (4 on one side of specimen, 5 on other side); anepisternum and katepisternum bare. One pair of short, stiff postalar setae present. Prescutellum absent. Scutellum with one pair of apical setae only; setae short, stout.

Wing: Length/width 2.4; hyaline, except for faint tint between Sc and R 1. Membrane microtrichia well developed over entire surface of wing, even in cell Sc. Two prehumeral costal setae at base of C; C with spinules, end near apex of R 2+3. Sc relatively short, apex slightly beyond level of crossvein r-m; R 1 straight, bare, length 0.72× the wing length; bases of Sc and R 1 close, divergent for apical half. Pterostigma absent. Vein R 4+5 ends at wing tip; cells rm and dm closed; crossvein br-m slightly basal to level of Sc apex; crossvein dm-cu close to wing margin, separated from margin 0.75× its length. M not forked (M 2 lost); M 1 bent in middle, deflected anteriad. Tip of CuA 1 incomplete; cell cup longer than vein at apex, cell not extremely acute or narrow; CuP slightly curved, not straight; CuP+A 1 tip incomplete. Legs: All femora without macrosetae, spines or tubercles. Dark bifid scales on all tibiae and tarsi: scattered on partial, lateral surface of tibiae, encircling ventral portion of tibial apex; in dense lateral row on tarsi. Metatarsomeres 1–4 flattened laterally, expanded; tarsomere 2 with blunt spine on lateroapical corner; tarsomere 3 with small, light, clavate seta preapically near row of bifid scales. Mesotibia with 2 ventroapical spurs, large one mesally (its length ca. diameter of tibia). Pulvilli well developed; empodium not observable (probably minute, setiform).

Abdomen: Tergites without macrosetae or setulae; 8 tergites visible; anterior 6 broad (1–4 broadest); tergite 7 narrow, longer than wide, tubular, ventroflexed (presumably circumverted); epandrium small, capsular. Male genitalia not observable (preservation insufficient). Sternites well developed, but lateral margins do not meet tergites (pleural membrane exposed).

SPECIMENS EXAMINED: Holotype, male, AMNH Bu-KL30-27, in Burmese amber. The fly is extremely well preserved, complete, though some details are obscured (e.g., small structures of the genitalia).

ETYMOLOGY: In reference to the anomalously early appearance of a platypezine in the mid-Cretaceous.

Figures

FIG. 8. Chandleromyia anomala, n. gen., n. sp. (Platypezidae), male holotype in Burmese amber, AMNH Bu-KL30-27. A. Dorsolateral habitus. B. Head, ventrolateral view. C. Dorsolateral view. D. Metatarsus. E. Male terminalia, left posterolateral view.

FIG. 33. Chandleromyia anomala, n. gen., n. sp. (Platypezidae), male holotype in Burmese amber, AMNH Bu-KL30-27. A. Wing. B. Antenna. C. Metatarsus, lateral. D. Thorax, lateral.