Proironia gibbera Grimaldi 2018, new species
Creators: name: Grimaldi, David A.
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Ironomyiidae
Proironia
Proironia gibbera

description: Proironia gibbera, new species
Figures 13, 41
DIAGNOSIS: Differs from the other species of the genus, also in Burmese amber, by the following: Head broader, concavity of occiput not nearly as deep; pedicel lobe long, more fingerlike, extended>0.5× the length of basal flagellomere (vs. less than this, lobe more triangular); notopleural, postalar setae shorter; thorax deeper, scutum more dome shaped (vs. slightly flattened on top); pro- and mesocoxae not setose (vs. with dense, fine setae); mesofemur with longitudinal groove, nearly length of femur (vs. without); wing with costal edge convex (vs. flat), apical fork of Sc-R 1 larger; apex of wing broadly rounded (vs. acute); fork of M 1 -M 2 with very short stem; crossvein dm-cu oblique to M 2 and CuA 1 (vs. perpendicular).
DESCRIPTION: Head: Rather broad, depth/ width 0.66. Occiput near posterior margin of eyes rimmed with row of stiff, whitish setae. Eyes: Bare, fully separated in female by distance slightly greater than outside width of lateral ocelli; no differentiation of facets. Frons: Dark brown, largely bare, with a few fine, scattered, minute setulae; lateral margins parallel, modest emarginations around bases of antennae; median furrow present, faint; no ocellar, postocellar or frontal setae present. Face below antennae relatively short; oral cavity exposed anteriorly; clypeus broad but narrow; oral margin rimmed by protruding membrane. Vibrissa absent. Antenna: Bases very close, oval; scape very small, conical; pedicel with fingerlike lobe inserted into lateral and mesal surfaces of basal flagellomere; basal flagellomere subcircular, laterally flattened; arista terminal, with 1 or 2 small basal articles (not clearly observed); arista bare. Mouthparts: Compact, not protruding beyond level of basal flagellomeres. Palp small, globular, light in color; labellum small, laterally flattened, extended slightly beyond level of palps. Thorax: Very deep, depth ca. 1.1× the length; scutum arched, almost hemispherical in profile. Scutum with scattered, very fine, decumbent setulae (barely visible); one pair of dorsocentral setae, short, stout, very close to anterior margin of scutellum; scutellum with 4 pairs of short, stout setae; 4 notopleural setae, located just above pleural cleft and anterior to transverse suture; 2 postalar setae; prescutellum well developed, lenticular. Wing: Relatively broad, width/length 0.51, apex broadly rounded, anterior (costal) edge convex (not flat); membrane entirely glassy, no microtrichia (even near wing margin). Vein C ends at apex of R 4 +5. Sc long, fused to R 1 for 0.62× its length, both veins free at base and apex. R 2 +3 and R 4 +5 long, nearly parallel; crossvein br-m very short; cell d long and narrow (L/ W 5.55), apex acute (crossvein dm-cu oblique). M 1 and M 2 joined at base by very short stem connecting to cell d; cell cup narrow, apex acute. A 1, A 2, anal lobe and alula not entirely visible.
Legs: Slender. All coxae with a few, fine, light setae; femora without macrosetae. Protibia with thick, short, preapical seta on mesal surface, ca. 10 short transverse, ctenidial-like rows of fine setae, apical row long and comblike; tarsomeres 1–4 with short ctenidial combs. Mesofemur with narrow but well-defined longitudinal groove on ventral surface (nearly length of femur), to which tibia must fit against. Mesotibia with minute, spurlike lobe on ventral surface, spurlike ventroapical sea; tarsomeres 1–4 with short rows transverse ctenidia. Metatarsus same as mesotarsus. Pretarsus with claws well developed, pulvilli slightly shorter than claws; empodium setiform.
Abdomen: Relatively short, tapered apicad; with fine, short, scattered setulae on tergites and sternites, no macrosetae. Eight tergites and 7 sternites visible, well developed, narrow pleural membrane exposed. Dorsal margin of tergite 7 very short, hidden beneath posterior margin of tergite 6. Cercus 1-segmented. Female Terminalia: Largely retracted, not visible.
SPECIMENS EXAMINED: Holotype, female, AMNH Bu-SE07, in Burmese amber. In excellent condition.
ETYMOLOGY: From Latin gibber (L., “hunched”).
description: Published as part of 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, pp. 1-97 in Bulletin of the American Museum of Natural History 2018 (423) on pages 1-97, DOI: 10.1206/0003-0090-423.1.1, http://zenodo.org/record/4613008