Burmapogon bruckschi, Dikow & Grimaldi, 2014

Dikow, Torsten & Grimaldi, David A., 2014, Robber flies in Cretaceous ambers (Insecta: Diptera: Asilidae), American Museum Novitates 3799, pp. 1-19 : 3-9

† Burmapogon bruckschi , new species

Figures 1–6

ZooBank LSID: C3FD7954 -CCD6-4512-BD36-03D3908236B3

(http://zoobank.org/urn:lsid:zoobank.org:act:C3FD7954-CCD6-4512-BD36-03D3908236 B3).

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ETYMOLOGY: This species is named aher Klaus-Peter Brucksch of Kuranda, Queensland, Australia, who acquired the amber piece containing the male holotype in the Hukawng Valley in Myanmar.

DESCRIPT ION: Approximate specimen length 6.5 mm (male holotype AMNH-BuKB1) and 8.0 mm (female AMNH-JZC Bu163 paratype). Head (fig. 3B): wider than high in anterior view; face wide, three times as wide as adjacent ommatidia, anterior ommatidia distinctly larger than lateral ones; mystax comprised of nine light-colored, stiff setae (male holotype AMNH-Bu-KB1), arranged in a single, transverse row on clypeal-facial margin; facial swelling not developed; frons markedly and abruptly diverging dorsolaterally; vertex sharply depressed; ocellar triangle prominent with a few, short ocellar (oc) setae; postocular (pocl) setae long, lightly angled anteriorly in distal half; median occipital sclerite without macrosetae; proboscis straight; maxillary palpus two-segmented, about 1/4 length of proboscis. Antenna (fig. 3A): scape and pedicel cylindrical, about equal in length, pedicel dorsally and ventrally microsetose; postpedicel parallel sided throughout, laterally compressed, microsetose throughout (particularly evident distally on anteroventral margin), about 1.5 times as long as combined length of scape and pedicel; stylus short, about 1/8 length of postpedicel, comprised of one element, stylus tapering distally, asetose, but densely covered by microtrichia, and positioned at dorsodistal tip of postpedicel, tipped with distinct apical, setalike sensory element.

THORAX: Pronotum divided into ante- and postpronotum, postpronotum much wider than antepronotum, antepronotal (aprn) and lateral postpronotal (lat pprn) setae present; postpronotal lobes only slightly extending medially, short setose; scutum covered with short posteroclinate setae, longer laterally and posteriorly, acrostichal (acr) and dorsocentral (dc) setae not distinguishable from scutal setation; no evidence of notopleural (npl), supraalar (spa), or postalar (pal) macrosetae; scutellum large, discal scutellar (ds sctl) and apical scutellar (ap sctl) setae present, all of same length; superoposterior anepisternum setose (but not macrosetose), anatergite asetose, katatergite setose; metakatepisternum small and not visible between mesothoracic and metathoracic coxae; postmetacoxal bridge absent, postmetacoxal area entirely membraneous.

WING: (figs 1C, 4): Length 4.0–4.1 mm; densely covered by microtrichia, veins brown; cells r1, r4, r5, m3, and cu p open; anterior margin of wing straight (C not bulging anteriorly), C circumambient; apex of R2+ 3 arching sharply anteriorly to meet C; R4 and R5 diverging from each other, R4 terminating very slightly anterior to and R 5 posterior to wing apex, R4 relatively straight (not sinuate); supernumerary stump vein (R3) at base of R4 absent; r-m distinct, positioned at the midline of cell d; distal end of cell d formed by base of M 2 and m-m in nearly a straight line; M1, M2, and M3 all reaching wing margin, CuA1 and CuA2 distinct, reaching wing margin, CuA2 approximating A1, but not closing cellup p; alula reduced in size to small lobe; microtrichia on posterior margin developed in a single plane; halter light brown.

LEGS: (figs. 1D, 5): Coxae directed ventrally, setose (not macrosetose), anterior metathoracic coxa without any protuberance; metathoracic trochanter simple, setose medially; femora of equal size (metathoracic femur slightly more expanded), setose (not macrosetose); prothoracic tibia straight, 3 posteroventral macrosetae (fig. 5C–D): 1 weak macroseta at slightly less than 1/2 length, 1 strong macroseta at 2/3 length, 1 strong macroseta at 4/5 length; 3–4 short anterodorsal macrosetae in distal 1/2, several short macrosetae at distal tip; mesothoracic tibia straight, 1 posteroventral macroseta at 2/3 length, several short antero- and posteroventral macrosetae in distal 1/2, several long macrosetae at distal tip; no evidence of prothoracic tibial projections (neither a small posteroventral S-shaped spur nor a large anteroventral spine); metathoracic tibia straight, expanded distally with a marked ventral indentation in distal 9/10 (fig. 5A–B); primarily macrosetose, shorter proximally, longer and stronger distally (particularly ventrally), long macrosetae at distal tip; ventral tip with distinct, long, trowel-shaped, partly laterally compressed macroseta (longer than adjacent “regular” macrosetae), with median surface hollow and facing tibia and tarsus; prothoracic and mesothoracic tarsomere 1 longer than tarsomeres 2–3 combined, metathoracic tarsomere 1 longer than tarsomeres 2–4 combined, each tarsomere short, macrosetose, and distally with 1 long anterior and 1 long posterior macroseta; empodium 2/3 length of claw, slightly curved dorsally; claws abruptly angled distally, pointed; pulvilli present, as long as claws, with two dorsal ridges.

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ABDOMEN (fig. 1A): Somewhat dorsoventrally flattened; tergites entirely sclerotized dorsally and smooth; tergites short, densely setose, marginal and medial macrosetae absent; T2 wider than long, T2–3 rectangular (not forming a distinct “waist”), T6 similar to T5 and not concealing distal tergites and terminalia.

MALE T ERMINALIA (figs 1E, 6B): T1–T7 well developed (T8 cannot be examined in detail), T7 and following tergites and terminalia partly retracted under T6; hypopygium not rotated and pointing posteriorly; epandrium separated medially and joining proximally, surstylus absent; epandrium and hypandrium not approximating (separated by gonocoxites); gonocoxites long setose distoventrally and protruding beyond tip of epandrium.

FEMAL T ERMINALIA (figs. 2D, 6A): T7 normally developed; T8 and following segments comprising ovipositor, T8 with erect setae, T8 with anterior rectangular apodeme (entirely fused to tergite); S8 platelike, slightly emarginate mediodistally, macrosetose posteriorly especially posterolaterally; T9 small and triangular, T10 divided into two heavily sclerotized acanthophorite plates with five acanthophorite spines on each plate, T 9–10 entirely fused.

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MAT E RIAL EXAMINED: Holotype male (fig. 1): Complete specimen ( AMNH-Bu-KB 1, ex Klaus-Peter Brucksch), in excellent condition, clearly visible with very little obfuscation by other inclusions. Proboscis partly obscured by right prothoracic leg and air bubble, hh side of head deformed by expanded air bubble, hh scutum and thorax partly covered by air bubble, and right mesothoracic tibia broken off. Paratype female (fig. 2): Complete specimen ( AMNH-JZBu- 163, in James Zigras Collection) in good condition, but in a rather turbid piece of amber in which not all morphological features are clearly visible. Portions of head and thorax obscured by air bubbles and abdomen damaged and disarticulated from T6 onward, but all structures remain embedded in the amber close to the main portions of the body. Both specimens agree in external morphology and can therefore be regarded to represent the same species without any apparent sexual dimorphism.

Figures

FIG. 1. Photomicrographs of †Burmapogon bruckschi (male holotype AMNH-Bu-KB1). A. Whole specimen lateral habitus (Morphbank: #832135). B. Head and antennae in lateral view (#832137). C. Wing (#832139). D. Leh metathoracic tibia and tarsus in median view (#832141). E. Male terminalia in lateral view (#832143).

FIG. 2. Photomicrographs of †Burmapogon bruckschi (female paratype AMNH-JZBu-163). A. Whole specimen lateral habitus (Morphbank: #832146). B. Right legs in lateral view (#832148). C. Head and antennae in lateral view (#832150). D. Disarticulated female terminalia in dorsolateral view showing acanthophorite spines (#832152

FIG. 3. †Burmapogon bruckschi (male holotype AMNH-Bu-KB1). A. Antennal postpedicel and stylus in lateral view. B. Head in anterior view (antennae omitted; note: hh side of head deformed by expanded air bubble and here reconstructed from right side).

FIG. 4. Wing of †Burmapogon bruckschi (male holotype AMNH-Bu-KB1)

FIG. 5. †Burmapogon bruckschi (male holotype AMNH-Bu-KB1). A. Tip of fteh metathoracic tibia and tarsomere 1 in median view. B. Tip of right metathoracic tibia and tarsomere dorsolateral view. C. Distal half of right prothoracic tibia in dorsal view. D. Tip of fteh prothoracic tibia in median view

FIG. 6. Terminalia of †Burmapogon bruckschi A. Female terminalia in dorsal view (female paratype AMNH-JZBu-163). B. Male terminalia in lateral view (male holotype AMNH-Bu-KB1