Nigripeza Marshall 2022, new genus
Creators: name: Marshall, Stephen A.
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Micropezidae
Nigripeza

description: Nigripeza new genus
Type species Grallipeza obscura Hennig, 1934:300.
Description: Size 7–8 mm. Colour: Head with frontal vitta orange to black, usually orange anteriorly and gradually grading to a darker colour posteriorly; face orange and palpus almost entirely dark; thorax mostly black to very dark brown with postpronotal lobe and supra-alar area paler in some species; wing clear with a broad dark discal band. Fore femur all or mostly brown on basal half, yellow distally. Fore tibia dark brown, fore tarsomeres 1–2 white, 3–5 brown to black. Other legs yellowish brown except darker coxa; mid femur with a single basal dark ring, sometimes obsolete; hind femur with 3 darker rings (subbasal, distomedian, preapical) but distal two often indistinct (distinct only in N. octa). Abdominal pleuron with a circular to elongate oval dark pleural sac on P2; pleuron of most species with parts of P1 and P3 white, otherwise mostly brownish with dark microsetulosity.
Head: Arista plumose, hairs at least as long as scape width. Pedicel with a ventroapical bristle longer than first flagellomere. Frontal vitta broad and parallel sided behind ocelli, expanded and elevated in front of ocelli, broadly meeting anterior margin. Orbital plate and epicephalon bare; paracephalon very finely microsetulose, ocellar plate small, dark and bare. Three well developed fronto-orbitals. Clypeus microsetulose posteriorly and anteriorly, otherwise bare. Palpus broad (approximately twice as long as wide) weakly convex ventrally and sharply tapering dorso-apically, black to dark brown except for pale base and an inconspicuous silvery distal and ventral fringe.
Thorax: Cervical sclerite with posterior third forming a prominent lobe in both sexes, most conspicuous in female. Postpronotal lobe distinctly elevated posteriorly, sparsely microsetulose and sometimes with a few very small, inconspicuous black hairs. One or two dorsocentral bristles. Suprahumeral bristles normally absent but anteriormost dorsocentral setula sometimes enlarged. Vertical row of katepisternal bristles dark brown to black.
Abdomen: Abdominal pleuron of both sexes (where known) with a dark pleural sac on P2, much more strongly developed in males.
Female abdomen (unknown for N. cali and N. octa): Tergites black, oviscape brown to black. Pleuron dirty white, slightly darkened with black microsetulae at least on segments 1-2. Major (paired) spermathecal duct elongate and almost parallel-sided, gradually expanded to a slightly swollen apex from which very long, transversely striate and strongly convolute stems lead to 2 funnel-shaped spermathecae. Spermathecae with distinct outpocketings at base and broad distal invaginations. Minor (single) duct smaller (N. spangleri) or much smaller (N. obscura) but similar in shape up to the stem.
Male abdomen: Genital fork variable, very short in some species, with stout bristles on mesal surface mostly clustered at apex. Distiphallus short and broad, ending in a broad phallic bulb, distal distiphallus absent. Ejaculatory apodeme variable.
Comments: Hennig (1934) included three black-bodied species in his key to Grallipeza species. Only one of these species (Grallipeza obscura Hennig) belongs in Nigripeza; the others (Grallipeza auriornata Hennig and Calobata pallidefasciata Macquart) are dark-bodied species with a bare or indistinctly pubescent arista, and probably belong in Calosphen. Three specimens of Nigripeza (two N. obscura, one N. octa) were sequenced for CO1 and recovered together as an isolated branch widely separated from the Grallipeza ss/ Calosphen clade on maximum likelihood trees including over 100 taeniapterine species (unpublished data).
Etymology: A number of widely separated clades traditionally treated as part of Grallipeza have been informally organized for several years using manuscript names with the suffix " peza ". Two of those clades are formally named using this suffix here, with the prefix " Nigri " (black) applied to this group of dark species now treated as the genus Nigripeza.
Key to the species of Nigripeza
1. Frontal vitta mostly dark, with black area tapering to anterior margin of frons (Fig. 7A). Ejaculatory apodeme very small and ejaculatory duct short (Fig. 7D)........................................... Nigripeza cali new species (Colombia)
- Frontal vitta orange at least on anterior quarter, usually much more; orange area gradually grading to darker pigmentation posteriorly. Ejaculatory apodeme small or large............................................................. 2
2. Hind femur with a distinct basal band more than twice as long as wide, a similarly dimensioned but very pale middle band, and an indistinct distal band (Fig 10D). Sternite 5 with a very short genital fork, arms much less than twice as long as wide and separated by less than the width of an arm (Fig 10B). Ejaculatory apodeme very small and ejaculatory duct short........................................................................... Nigripeza spangleri new species (Ecuador)
- Hind femur with a basal band less than twice as long as wide and a slightly longer distomedian band (indistinct in N. obscura); sternite 5 with a long genital fork, arms widely separated and more than twice as long as wide (Figs. 8B, 9D). Ejaculatory apodeme as large as epandrium, with a long duct............................................................ 3
3. Frontal vitta entirely orange anterior to ocelli, slightly darkened posteriorly. Distomedian black band of hind femur indistinct. Arms of genital fork much shorter than body of sternite 5. One dorsocentral bristle. South America........................................... Nigripeza obscura (Hennig) (Bolivia, Brazil, Colombia, Guyana, Ecuador, French Guiana, Peru)
- Frontal vitta orange only in anterior third, fading to reddish brown posteriorly. Distomedian black band of hind femur distinct. Arms of genital fork subequal to body of sternite 5. Two dorsocentral bristles. Central America........................................................................................... Nigripeza octa new species (Costa Rica)
description: Published as part of Marshall, Stephen A., 2022, Amapeza and Nigripeza, new genera of Neotropical micropezid flies (Diptera, Micropezidae, Taeniapterinae), pp. 251-272 in Zootaxa 5092 (3) on pages 264-265, DOI: 10.11646/zootaxa.5092.3.1, http://zenodo.org/record/5881128