Eosciadocera pauciseta Grimaldi 2018, new species
Creators: name: Grimaldi, David A.
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Phoridae
Eosciadocera
Eosciadocera pauciseta

description: Eosciadocera pauciseta, new species
Figures 16, 47D; 49A, D, E
DIAGNOSIS: Similar to Eosciadocera setosa, also in Baltic amber, by the very large body size (6–7 mm), protibia with only a ventroapical macroseta; one large pair of vertical setae; pair of small (divergent) postocellar setae; basal flagellomere subspherical; 1 to several rows of large acrostichals; proepisternum with many large setae; and anepisternum without large setae. Proleg with stridulatum. Differs from E. setosa by the following: two (vs. four) pairs fronto-orbital setae; frons broad, greater than ½ head width (vs. ¼); palp relatively large, flat, with stout black setae on distal margin (vs. small, fine setae); proscutellum absent (vs. present); notopleurals 4 (vs. 5–8); scutellars in two pairs (vs. 5–6 pairs); metafemur without macrosetae (vs. 5–6 long ones).
DESCRIPTION: Large, ca. 6.7 mm body length; color appears brownish overall, with thick, black macrosetae. Head: Eyes well separated, bare, no differentiation of facets, no emarginations. Frons without median sulcus, broad (ca. 0.65× width of head), length (from anterior ocellus to anterior margin) shorter than width. Ocellar triangle approximately in middle of dorsum of head (including frons). Frontal setae: two pairs frontoorbitals (posterior pair lost, but sockets visible), situated near middle of frons length; ipsilateral fronto-orbitals separated by distance ca. 5× diameter of fronto-orbital seta socket. Supraantennal interfrontals possibly absent (or just lost in specimen). One pair of vertical setae present (setae lost, but sockets visible), situated midway between posterior fronto-orbital and row of postocular occipital setae. Ocellar setae: 1 pair (lost, but sockets visible, apparently large); postocellars minute, fine, length slightly greater than diameter of ocellus, located between posterior ocelli. Occiput just behind posterior margins of eye with 19–20 long, stout postocular setae; 7–8 additional large occipital setae mesal to this row. Face deeply concave, with very thin vertical carina, flanked by pair of recessed areas (fossae) for antennae. Vibrissa absent. Antenna: Scape very narrow, ringlike, no setae; pedicel short, conical, no setae. Basal flagellomere subspherical (length slightly greater than width), covered with short, velvetlike pile. Arista dorsal; 3-merous, basal two articles short (lengths ca. 2× their widths). arista micropubescent. Mouthparts: Oral margin protruding, such that oral cavity faces forward, surrounded by short sleeve. Palp large, flattened, distal margin with thick, short setae. Labellum fully recessed into oral cavity (as preserved); opened lobes nearly forming circle, pseudotracheae not visible, though minute microtrichia are.
Thorax: Heavily bristled; scutum gently arched; proscutellum absent or very reduced; prosternum large, fully exposed, bare. Acrostichals large, in even central row of ~10 setae; row of ~10 dorsocentral setae lateral to acrostichals (setae in both rows about same size). Other thoracic setae: 1 large postpronotal; oblique row of 6 supraalars (1 very large); 1 large postalar; 4 large, presutural notopleurals; 6–7 large proepisternals (rest of pleuron without setae). One pair of large dorsocentrals, sockets slightly lateral to line formed by outer row of acrostichals; 2 pairs of large scutellars (lengths very similar), apical scutellars very close. Wing: Very long, ca. 8 mm, nearly twice length of abdomen. Membrane of wing clear, no infuscation, entirely covered with microtrichia. Tegula bristly, with 7–8 thick setae; basicosta with row of 4 large setae; vein h thick; Sc thick, fused to R 1 at 0.30× length of R 1; C with 2 rows thick spinules, vein ends at apex of R 4+5; R 2+3 ends midway between apices of R 1 and R 4+5. Vein R 4+5 ends well before apex of wing, fully fused to C. Base of M 1 lost, evanescent, apex of M 1 ending at wing tip; M 2 complete, including base. Cu veins complete; anal vein present, incomplete. Cell r-m complete (closed basally); cell dm slightly opened basally and distally; cell cup present, apex of CuA 2 not fused to A 1. Alula small, with fringe of 10–12 stiff, nonfeathered setae. Legs: Pretarsi with curved bristle near where empodium would be (as in Ironomyia); tarsomeres 1–4 with hair seam on mesal surface, 2 longitudinal rows of dark, small, spinulelike setae ventrally. Foreleg: Coxa heavily setose overall, with>30 thick, large macrosetae; femur without macrosetae; stridulatum present, “scraper” exposed on bare, light patch at base of inner surface of right fore femur, with about 12 minute ridges; tibia with only ventroapical macroseta, no others. Midleg: coxa setose, ca. 10 setae; femur without macrosetae; tibia with 2 middorsal setae, 4 apical ones. Hind leg: coxa with a few fine setae; femur with single ventrolateral macroseta; tibia with pair of middorsal macrosetae, plus 4 apical ones. Abdomen (female): Sternites well developed; apical segment with longer, thicker setae; pair of long, fine setae just above cerci (on epiproct?); cerci short, pointed downward, setose.
SPECIMENS EXAMINED: Holotype, female, AMNH Ba-JVe565, in Eocene Baltic amber. The specimen is complete, but portions of it are covered in milky coating or are obscured by fractures.
ETYMOLOGY: From Latin paucus (“few”), in reference to its fewer setae compared to setosa.
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