Hilarimorphites cummingi, Grimaldi, 2016

Grimaldi, David A., 2016, Diverse Orthorrhaphan Flies (Insecta: Diptera: Brachycera) In Amber From The Cretaceous Of Myanmar: Brachycera In Cretaceous Amber, Part Vii David A. Grimaldi, Bulletin of the American Museum of Natural History 2016 (408), pp. 1-132 : 90-92

Hilarimorphites cummingi , new species

Figures 32 , 64

DIAGNOSIS: Distinctly differs from other species in the genus by the very short, almost nonexistent stem vein M 1+2; the short, closed cup cell with a long CuA 2 + A 1 vein; and the apices of veins M 1, M 2, CuA 1, and CuA 2 +A 1 evanescent and incomplete. Other details are given under Comments.

DESCRIPTION: Based on female. A small, robust, entirely dark-bodied fly with very sparse setae and setulae and relatively short wings. Body length 2.13 mm; thorax length 0.61 mm; abdomen length 1.32 mm; wing length 1.14 mm; antenna length 0.23 mm. Head: Approximately hemispherical, with largest surface of eyes frontally. In lateral view significant occipital surface exposed behind eye. Eye entirely bare, no differentiation of facets; inner (medial) margins bordering frons well separated, margins parallel; no emargination near antennal base. Occiput with lateral portions bulging, central portion concave dorsally but not ventrally; with very sparse, minute, fine setulae; pairs of small, very short, stiff setae flanking ocellar triangle just posterior to eye margin. Frons glabrous, dark; ocellar triangle slightly raised above frons surface, on vertex of head. Antenna: Scape very short, ringlike; pedicel slightly longer and thicker, with circlet of fine setae; basal flagellomere largest antennal article, drop shaped in lateral view, with small 2-articled stylus; 2nd article of flagellum (basal article of stylus) very small, ringlike; 3rd (apical) flagellum article 3× length of 2nd, greatly tapered apicad (right antenna with stylus teratological, having a duplicated apical article). All flagellar articles with microtrichia, vestiture slightly longer on ventral surface of flagellomere 1. Mouthparts: Short, labellum rounded (with lobes closed), having fine setae on outer surface. Labium very short, exposed; palp short, clavate, 1-segmented. No other mouthparts exposed. Thorax: Relatively short, compact, notum barely arched. Scutum with median, glabrous strip, bordered laterally by setulose patches. One pair short, stiff, stout dorsocentral setae present, just anterior to scutellum; scutellum with pair of short, apical setae that nearly cross at apices (size equal to dorsocentrals); one seta on each supraalar ridge, slightly larger than others. No prescutellum present; scutellum short, apex slightly tilted upward. No notopleural setae present. Pleura orientation essentially vertical, not oblique. Antepronotum short; postpronotal lobes small; katepisternum narrow, vertical. Wing: Short, broad, W/L ca. 0.52 (base obscured), apex reaching to abdominal segment 5. Vein Sc short, ends slightly past tip of R 5; Sc complete, but thin, ca. 0.3× length of wing; R 1 short, ca. 0.5× wing length, close and parallel to Sc; no pterostigma; R very slightly sinuous; basal R veins very thick, fork of R 4 -R 5 thinner and lighter, stem vein R 4+5, slightly shorter than fork of R 4 -R 5; R 4 -R 5 fork slightly divergent, nearly symmetrical. Cell br slightly thinner and longer than cell bm; cell d fairly large, W/L 0.3, situated near center of wing. Veins M 1, M 2, CuA 1, and CuA 2 +A 1 with apices evanescent, incomplete (not reaching wing margin); M 1 slightly sinuous; stem vein M 1+2 very short, these veins almost connected directly to cell d; M 3 absent; cell cup short, closed, with long CuA 2 +A 1 vein. Anal lobe well developed; alula narrow. Legs: Coxae contact thorax at bases only, suspended, with several fine setae on anterior faces. Metacoxa with well-developed peg/tubercle on anterior surface. Leg segment lengths (all pairs): tibia> femur> basitarsomere = tarsomeres 2–5. No tibial spurs. Pretarsus with empodium setiform; pulvilli rather small, significantly shorter than claws. Abdomen: Relatively long, slender, longer than thorax + head (including antennae), does not appear to be telescoping. Eight large tergites; sternites well developed; tergites 2, 3 largest, all with fine, short, erect and decumbent setulae. Cercus rather small, dorsoapical, setulose, with two pairs of long setae.

TYPE: Holotype, female, JZC Bu-177.

ETYMOLOGY: Patronym for Jeff Cumming, Canadian National Collection of Insects, Agriculture Canada, Ottawa, for his outstanding contributions to the morphology and systematics of Diptera .

COMMENTS: The very short stem of M 1+2 of H. cummingi is unique among all fossil apystomyiids, including Apystomimus , as are the evanescent, incomplete apices of the M and CuA veins. The long vein CuA 2 +A 1 is also unique; in all other fossils these veins meet just before or at the wing apex, or (in H. burmanica ) not at all. It is interesting that the four species of Hilarimorphites in New Jersey amber have a 2-articled flagellum; the ones in Burmese amber have it 3-articled (i.e., a 2-articled stylus). In H. burmanica the second flagellar article is long, with a minute apical article; in H. cummingi the second article is short and ringlike. The venation of H. cummingi is actually quite similar to that of Proratites simplex Grimaldi and Cumming , in New Jersey amber, originally assigned to Scenopinidae (Proratinae) , although that assignment is questionable. The two species differ since Proratites has a long, stylate flagellar article, lacks thoracic setae, and has various venational differences (larger cell d, M and Cu veins complete, shorter CuA 2 +A 1 vein, asymmetrical R 4 -R 5 fork). This new species adds further evidence to the past diversity and relict nature of Apystomyiidae .

Figures

FIG. 32. Hilarimorphites cummingi, new species (Apystomyiidae), JZC Bu-177, holotype. A. Wing. B. Apices of antennae, detail. C. Head, oblique left lateral view. D. Thorax, dorsolateral view. E. Female terminalia, left lateral view.

FIG. 64. Hilarimorphites cummingi, new species (Apystomyiidae), holotype JZC Bu-177. A. Habitus, right lateral. B. Habitus, left lateral.