Alavesia lanceolata, 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 : 16

Alavesia lanceolata , new species

Figures 1D , 2D , 6A , 8A , 13A

DIAGNOSIS: A larger species (fig. 13A) (wing length 1.8 mm), male postpedicel broad and large (L/ W 3.4 – 4.0), tapered on apical half, stylus short (0.35x L of postpedicel); 3 pairs of scutellar setae; M 1+2 and R 4+5 parallel for much of their length but slightly divergent at apex (parallel in A. zigrasi ); crossvein dm-m clearly positioned beyond apex of cell bm; CuA arched apically (hybotidlike); female aristalike stylus slightly longer than postpedicel (female with similar CuA and thickened setae).

DESCRIPTION: Male. Coloration preserved: Frons and vertex dark brown. Pleura light including halter, except for anepisternum (which is light, fuscous brown, same color as scutum and dorsum of scutellum). Femora and tibiae light, tarsi dark. Tergites 1–5 dark, posterior ones light. Head: Scape short, pedicel quadrate, postpedicel broad and large (figs. 1D, 8A) (L/ W 3.4 –4.0), tapered on apical half, stylus short (0.35 × L of postpedicel). Palpus very small; proboscis barely projecting beyond oral margin.

Thorax: Macrosetae thickened, acrostichals short, biserial; dorsocentral setae similar to acrostichals, ending in pair of long prescutellar dorsocentrals>2 × length of preceding ones. Postpronotum with 1 small seta, barely larger than setulae; notopleural setae of graded lengths, 3 posterior ones largest; 1 postsutural supraalar seta; 1 postalar seta; 3 pairs scutellar setae, lateral pair ~0.3 × length of apical pair, apical pair upright and crossed.

Legs: Forecoxa with short, decumbent setae on anterior surface. Forefemur with row of short, spinulelike setae on distal 2/3 of ventral surface; none on mid femur, a short distal row on hind femur. Foretibia with long, apical ventral seta; mid and hind tibiae with 2 such setae (1-2-2). Hind tibia with dense dorsal row of setae, lengths about 1/3 width of tibia; posterior surface with fine brush of setae.

Wing: Length 1.8 mm, slender, L/ W 2.66 (fig. 2D). Vein C terminating slightly beyond M 1+2; Sc nearly reaching costal margin; R 4+5 parallel to M 1+2 but diverging at apices; crossvein r-m near middle of cell dm; apex of M 4 slightly closer to CuA+CuP than to M 1+2; CuA arched, not aligned with bm-m; apex of cell cua acute, cell cua longer than cell bm; CuA+CuP slightly curved.

Abdomen: Shorter than thorax; setae short, little differentiated except for margins of sternites 2–5 with short, thick, spinulelike setae. Male terminalia distinctive (fig. 6A): Epandrium short, ringlike, ventral lobe with relatively shorter setae ~0.5 × length of epandrium; posterior surface of terminalia extensively membranous, cerci small and separated by distance about equal to their diameter. Surstylus short, digitate, simple (no apparent dorsal lobe). Terminal median structure (postgonites + phallus) lobelike, very integrated, having small lateral lobe with central depression, apically microtrichose and with pair of downturned, spinelike apical lobes/setae.

TYPE MATERIAL: Holotype, male, USNM PAL 726868 .

ETYMOLOGY: The specific epithet is named in reference to the broad, lanceolate postpedicel.

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 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 8. Heads and antennae of Burmese amber Alavesia. A. A. lanceolata, head and antennae, dorsolateral view, holotype, USNM 726868. B. A. pankowskiorum, head and antennae, lateral view, paratype, AMNH Bu-KL7-19. C. A. magna, left antenna, lateral view, holotype, AMNH Bu-KL2-7. D. A. magna, left antenna detail, lateral view, holotype, AMNH Bu-KL2-7. E. A. brevipennae, lateral view, AMNH Bu-494. Note the longer microtrichia on the postpedicel. F. A. longicornuta, holotype, stylus tip, lateral view, 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.