Canadopeza biacrosticha, 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

Canadopeza biacrosticha , new species

Figure 29

DIAGNOSIS: As for genus, by monotypy.

DESCRIPTION: (Female only). Head: Eyes (partially collapsed in unique specimen) female dichoptic, eyes well separated (face and frons broad), bare, no facet differentiation or emargination of eye edges. Median furrow of frons (presence/absence) not observable; at least 2 pairs short, fine fronto-orbital setae present (fracture obscures observation of anterior portion of frons); no vertical setae; postocular setae very fine, short. Ocelli slightly raised; triangle with 1 pair short, stout, upright setae. Vibrissa, genal setae absent; occiput without large setae, circlet of fine setulae around cervical connection.

Antenna: Scape setulose; pedicel about same length as basal flagellomere, with setulae on apical rim; arista terminal; basal flagellomere small, short and conical; 3 aristomeres, basal 2 minute (basalmost one longer), apical aristomere fine, with micropubescence. Mouthparts: Clypeus narrow; palp of moderate size, protruding beyond oral margin. Labellum well developed, with ~7 pseudotracheae on each lobe.

Thorax: Scutum rounded but not arched. Acrostichals in 2 even rows of ~20 setae; short, decumbent, stiff. One pair of large, prescutellar dorsocentrals present, row of ~15 small, evensized ones anterior to each; 2 rows of short, fine lateral scutal setae on each side. One short postalar seta; no supraalars; 3 short, fine notopleural setae (middle one longest). Prescutellum absent; scutellum side, short, with row of 4 pairs of setae (middle ones largest). Wing: Relatively short and broad, appears entirely hyaline (any infuscation on costal edge unapparent); membrane entirely covered with microtrichia (even on sc cell). One prehumeral costal seta present; C terminates at apex of M 1, C with well-developed spinules. Sc relatively short, apex near level of r-m vein, R 1 short, 0.6× length of wing; Sc and R 1 divergent, not parallel; pterostigma absent. Apex R 2+3 slightly upturned; R 4+5 ends near wing tip; R veins thicker than others; cells rm and bm complete; crossvein dm-cu near middle between fork of M+CuA 1 and wing apex (cell dm short). M 1+2 forked, slightly asymmetrical, M 2 very faint (almost spectral). Vein CuA 2 curved (not straight); cell cup large, longer than terminal vein; anal lobe well developed, alula not observ- able. Legs: Lacking macrosetae, except for stout ventroapical spur on mesotibia. No dark, bifid scales on legs. Basitarsomeres of all legs equal to or slightly longer than combined length of distal tarsomeres; no metatarsomeres flattened or expanded. Puvilli well developed; empodium not observable, probably minute.

Abdomen: Tergites and sternites well developed, apparently without macrosetae. Female Terminalia: Four apical segments telescoping, approximately equal in length; cerci simple, with pair of dark hypoproct lobes protruding at base ventrally.

SPECIMENS EXAMINED: Holotype, female, RTMP 96,9 .26. Deposited in the Royal Tyrell Museum of Paleontology , Drumheller, Alberta, Canada. The specimen is complete and in good condition, although flows and fractures within the amber prevent observation of some structures.

ETYMOLOGY: In reference to the two rows of acrostichal setae.

Figures

FIG. 29. Canadopeza biacrosticha, n. gen., n. sp. (Platypezidae), holotype female, RTMP 96.9.2, in Late Cretaceous amber from Canada. A. Dorsolateral habitus, as preserved. B. Wing, reconstructed. C. Head, oblique frontal view.