Alavesia latala, Sinclair & Grimaldi, 2020

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 : 17

Alavesia latala , new species

Figures 1F , 2E , 13C

DIAGNOSIS: Wing short, broad, L/ W 2.15, apex broadly rounded (fig. 13C); R 4 +5 and M 1 parallel for entire length; apex of CuA strongly recurved, anal lobe absent. Postpedicel triangular, L/ W 2.48, arista 0.54 × length of postpedicel .

DESCRIPTION: Male. Coloration not preserved. Head: Scape short, setose; pedicel slightly larger, quadrate, postpedicel an elongate triangle, lanceolate (fig. 1F), L/ W 2.48; stylus relatively short, thick, 0.54 × length of postpedicel, with two minute basal articles.

Thorax: Macrosetae thickened; acrostichals not fully visible; dorsocentrals ending in stout pair of long prescutellars; postpronotal lobe with 3 short setae; notopleurals not fully visible, but 3 well-developed ones visible; 1 postsutural supraalar seta, 1 postalar seta; 3 pairs scutellar setae, apical pair upturned and crossed, lengths ~2 × that of lateral-most pair.

Legs: Forecoxa with dense setae on anterior surface. Forefemur with some fine ventral spinules, but complete distribution not visible; mid and hind femora with spinelike setae near apex only. Tibiae with long apical, ventral seta(e): 1-2-2. Hind tibia with dorsal row of ~6 thicker setae, lengths about half width of tibia; posterior surface with short brush of fine setulae.

Wing: Length 1.55 mm (fig. 2E), vein C terminating slightly beyond M 1+2; Sc nearly reaching costal margin; R 4+5 perfectly parallel to M 1+2; crossvein r-m at middle of cell dm; apex of M 4 equidistant between M 1+2 and CuA+CuP; CuP recurved, in line with bm-cu; apex of cell cua truncate; cell cua shorter than cell bm; vein A well developed but incomplete; anal lobe very narrow.

Abdomen: About same length as thorax; setation mostly not visible. Terminalia mostly not visible, but ventral margins of epandrium with fringe of long setae; surstyli very slender, digitiform.

TYPE MATERIAL: Holotype, male: AMNH Bu-1476. The fly is complete but preserved in turbid amber (fig. 13C), which obscures some details (i.e., of genitalia). Despite the preservation, the distinctive wing shape and venation allowed a reliable diagnosis of this species.

ETYMOLOGY: In reference to the broad wing, from Latin latus (broad) and ala (wing).

Figures

FIGURE 2. Wings of six species of Alavesia in Burmese amber. All are males, to the same scale. Specimens: A. USNM PAL 726867. B. AMNH Bu-494. C. AMNH Bu-496. D. USNM PAL 726868. E. AMNH Bu-1476. F. JZC Bu-556.

FIGURE 13. Alavesia spp. in Burmese amber. A. A. lanceolata, USNM PAL 726868. B. A. pankowskiorum, USNM PAL 726869. C. A. latala, holotype, AMNH Bu-1476. D. A. longicornuta, holotype, JZC Bu-556

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.