Alavesia longistylata Zhang and Wang

Sinclair, Bradley J. & Grimaldi, David A., 2020, Cretaceous diversity of the relict genus Alavesia Waters and Arillo (Diptera: Empidoidea: Atelestidae), American Museum Novitates 2020 (3961), pp. 1-40 : 25-26

Alavesia longistylata Zhang and Wang

Figures 1H , 3A , 6B–C , 9E , 11A , 14B–C

Alavesia longistylata Zhang and Wang in Zhang et al., 2020.

DIAGNOSIS: Like A. longicornuta , sp. nov., males characterized by greatly lengthened aristalike stylus (2 × length of postpedicel) (fig. 14B, C), bearing an apical, flaglike expansion; palpi elongate, narrow, projecting; CuA strongly recurved, cell cua truncate; M 1+2 and R 4+5 parallel. Differences with A. longicornuta given in diagnosis of that species.

REDESCRIPTION: Male. Coloration, except stylus, not preserved. Head: Scape and pedicel quadrate, subequal in size and length. Postpedicel greatly lengthened (fig. 1H), L/ W 3.3, tapered throughout, longer than head height. Stylus with two small basal articles, apical aristalike stylus 2 × length of postpedicel; apex of stylus with darkened, flaglike flattened expansion, twice width of apex of postpedicel. Palpus slender and elongate, tapered apically (fig. 9E), length about two-thirds as long as eye height; ventral edge with short, erect setulae; apex with several longer, curved setulae.

Thorax: Chaetotaxy thickened: uniserial row of short acrostichal setae; dorsocentral setae similar to acrostichals, ending in pair of long prescutellar dorsocentral setae; 1 anterior and 1 posterior postpronotal seta; 4 anterior notopleural setae of variable lengths, 1 posterior notopleural seta; 1 postsutural supraalar seta; 1 postalar seta; 1 pair of apical scutellar setae.

Legs: Forecoxa with short erect anterior setae; anteroapical setae longer and stouter. Femora (fig. 11A) with anteroventral row of short setae. Mid and hind coxae with 2–3 stout lateral setae on apical half. Tibiae with biserial row of short, stout ventral setae; apex of tibiae with long, apical ventral seta; hind tibia with dorsal row of setae, length about half width of tibia.

Wing: Length 1.9 mm (fig. 3A), costa terminating slightly beyond M 1+2; Sc nearly reaching costal margin; R 4+5 parallel to M 1+2, slightly divergent near wing margin; crossvein r-m opposite near middle of cell dm; apex of M 4 equal distance between M 1+2 and CuA+CuP; CuA straight, strongly recurved; apex of cell cua truncate, length of cell cua shorter than cell bm; CuA+CuP mostly straight, curved subapically to wing margin.

Abdomen: Setae short, without distinct posteromarginal setae. Segments 1–5 broad, remaining segments retracted with segment 5. Terminalia (fig. 6B, C): cercus finely setose; truncate apically. Epandrium U-shaped with broad dorsal bridge anterior to cerci; row of ~7 long setae along posteroventral margin, half length of epandrium. Surstylus very narrow and elongate, digitiform, projecting nearly vertically from epandrium, slightly shorter than apical epandrial setae; surstylus having thinner, shorter dorsal lobe. Phallus slender, sclerotized projection; strongly bent subapically with apex arched ventrally, tip microsetulose.

MATERIAL EXAMINED: Male, USNM PAL 726872.

Figures

FIGURE 3. Wings of three species of Alavesia in Burmese amber. All are to the same scale. Specimens: A. USNM PAL 726872. B. USNM PAL 726873. C–E. A. pankowskiorum, see figure for specimen numbers. F. Undetermined species.

FIGURE 6. Male terminalia of three species of Alavesia in Burmese amber, shown in various views, to the same scale except for B. A. A. lanceolata, USNM PAL 726868, dorsolateral view. B, C. A. longistylata, USNM PAL 726872. B. Lateral view of abdominal apex. C. Epandrium and genitalia, posterolateral view. D, E. A. magna, AMNH Bu-KL2-7. D. Ventrolateral view. E. Dorsal view. Abbreviations: cer, cercus; ep, epandrium; pg, postgonite; pg+ph, postgonite + phallus (integrated); ph, phallus; st8, sternite 8; sur, sustylus; t8, tergite 8.

FIGURE 9. Mouthparts of Burmese amber Alavesia. A. A. zigrasi head, lateral view, AMNH Bu-KL9-21. B. A. zigrasi (same specimen as A), mouthparts, showing labellum with pseudotracheae, labrum, hypopharynx. C. A. longicornuta, holotype, JZC Bu-556, showing setose palps. D. A. longicornuta, paratype, USNM PAL 726871, showing setose palps. E. A. longistylata, USNM PAL 726872, showing slender, setose palps.

FIGURE 11. Legs of Alavesia sp., showing the longitudinal furrows on the femora and tibiae (arrows). A. A. longistylata, fore and mid femora. B. A. magna, holotype, fore and mid femora, posterior surface. C. A. magna, holotype, hind tibiae. D. A. pankowskiorum, hind femur posterior/lateral surface, USNM PAL 726869. E. Alavesia sp., mid and hind femora, female, JZC Bu-1729. F. Alavesia sp., fore femur, posterior/lateral surface, same specimen as in E. G. Alavesia sp., right fore femur lateral surface, female, USNM PAL 726874.

FIGURE 14. Alavesia spp. in Burmese amber. A. A. longicornuta, paratype male, USNM PAL 726871. B, C. A. longistylata, USNM PAL 726872.

FIGURE. 1. Antennae of Burmese amber Alavesia species, lateral views. All are males except N, O, P. Some antennae were reversed in direction for optimal comparison; longicornuta and longistylata are slightly reconstructed to account for curvature of the stylus. All are to the same scale. Specimen numbers: A. USNM PAL 726867. B. AMNH Bu-494. C. AMNH Bu-496. D. USNM PAL 726868. E. AMNH Bu-KL2-7. F. AMNH Bu-1476. G. JZC Bu-556 (AMNH). H. USNM PAL 726872. K. USNM PAL 726869. L. AMNH Bu-KL7-18. M. JZC Bu-282. N. Undetermined species. O. A. zigrasi. P. A. zigrasi.