Palaeopetia terminus, 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

Palaeopetia terminus , new species

Figures 12 ; 38C, D, F, G, I ; 40A

DIAGNOSIS: Distinguished from P. dorsalis , n. sp., as given in the diagnosis above.

DESCRIPTION: Very similar to P. dorsalis with the exception of the following features: Head: Antenna with arista terminal, not dorsal-preapical. Male eyes large, holoptic for length of approximately 8 facets; ocellar triangle and small portion of frons exposed; no differentiation of facets; ocelli on low tubercle, close together. Thorax: Posteriormost notopleural seta very long and robust, ca. 2× the length and width of other notopleurals; 2 (vs. 1) postalar setae (anterior one finer). Transverse suture well developed. Anteriormost scutellar seta very small, length less than 0.3× that of adjacent scutellar seta (vs. approximately equal in size). Legs: Hind tibia with dorsal row of 6 stout, slightly curved setae, alternating with smaller stout setae. Wing: As drawn: longer, L/ W 1.89 (vs. 1.77), from tip to level of crossvein h. M 1 slightly more arched; microtrichia confined to wing margin. Terminalia: Epandrium glabrous, brown, apparently heavily sclerotized; laterally flattened (clamlike), with fine setae on inner edge; surstylus pendulous, setulose, curved and clavate, apparently articulating with ventrolateral portion of epandrium (not fused). Aedeagus and paraphallic structures not observable.

SPECIMENS EXAMINED: Holotype, male, AMNH Bu-SE2/6, in Burmese amber. In excellent condition.

ETYMOLOGY: In reference to the position of the arista on the basal flagellomere.

Figures

FIG. 12. Palaeopetia terminus, n. sp. (Ironomyiidae), holotype male in Burmese amber, AMNH Bu-SE2/6. A. Left lateral habitus. B. Right lateral view of head and thorax. C. Legs.

FIG. 38. Palaeopetia n. spp. (Ironomyiidae) in Burmese amber. A, B, E, H. P. dorsalis, holotype male, AMNH Bu-FB34. C, D, F, G, I. P. terminus, holotype male, AMNH Bu-SE2/6. A, C. Midlegs. B, D: Portions of hind leg. E, F: antenna, lateral. G, H: Thorax, as preserved. I: Male terminalia, ventrolateral view.

FIG. 40. Wings of fossil Ironomyiidae in Burmese amber. A. Palaeopetia terminus, AMNH Bu-SE2/6. B. Palaeopetia dorsalis, AMNH Bu-FB34. C. Proironia gibbera, AMNH Bu-SE7.