Plyomydas phalaros Castillo & Dikow 2017, sp. nov.
Creators: name: Castillo, Stephanie
name: Dikow, Torsten
Publisher: name: Zenodo
Year: 2017
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Mydidae
Plyomydas
Plyomydas phalaros

description: Plyomydas phalaros sp. nov.
ZooBank AA0C21E1-0420-4A8A-93F3-40DC17864BCE
Figs. 15–20, 24–27
Diagnosis: The species is distinguished from congeners by the scutal pubescence pattern with four pairs and a postero-median grey pubescent spot (Figs.15–16, 19–20), and the presence of a grey pubescent stripe on the posterior anepisternum (Figs. 16 and 20).
Etymology: From Greek phalaros = white-spotted, referring to the distinctive grey pubescent spots on the scutum.
Description: Head: brown, in general grey pubescent; width distinctly greater than thorax, interocular distance on vertex larger than at ventral eye margin, vertex between compound eyes slightly depressed, parafacial area very narrow, facial gibbosity nearly touching median eye margin; facial gibbosity distinct, welldeveloped and discernible in lateral view; mystax brown, covering facial gibbosity except dorso-medially; frons not elevated, laterally grey pubescent, medially apubescent; vertex apubescent; postgena lightly grey pubescent; setation: vertex brown, frons brown, ocp setae yellow, pocl macrosetae brown; ocellar triangle apubescent; proboscis brown, long, reaching fronto-clypeal suture; labellum large, much wider than prementum, longer than prementum and as long as oral cavity, unsclerotized laterally; maxillary palpus cylindrical, light brown, about 1/3 length of proboscis.
Antenna: brown, bulbous part of postpedicel light brown, scape and pedicel black setose dorsally and ventrally, rarely brown setose dorsally and ventrally; postpedicel cylindrical in proximal ½, symmetrically bulbous in distal ½, ≥5.0 times as long as combined length of scape and pedicel, bulbous part brown setose dorsally and ventrally; apical seta-like sensory element situated apically in cavity on postpedicel.
Thorax: brown, predominantly apubescent with distinct grey pubescent scutal and pleural spots; scutum uniformly black, surface predominantly smooth, postero-paramedially rivose, lightly grey pubescent with distinct grey pubescent spots: 1 pair anteroparamedially, 3 pairs laterally (1 antero-laterally, 1 at transverse suture, 1 postero-laterally), 1 spot postero-medially, scutal setation comprised of pubescent spots long black or brown setose; dc setae pre- and postsuturally black, acr setae absent, lateral scutal setae brown, npl setae 0, spal setae 0, pal setae 0; antepronotum dorso-medially smooth (without any indentation); postpronotal lobe brown, predominantly grey pubescent; proepisternum, lateral postpronotum, and postpronotal lobe long black setose; scutellum lightly grey pubescent, laterally densely grey pubescent, brown setose, apical scutellar setae absent; mesopostnotum, anatergite, and katatergite lightly grey pubescent, asetose, katatergite elevated and smoothly convex; anterior anepisternum lightly grey pubescent, asetose, supero-posterior anepisternum grey pubescent, asetose; posterior anepimeron long brown setose, katepimeron asetose; metanepisternum lightly grey pubescent, asetose, metepimeron evenly elevated, same color as T1, grey pubescent, asetose; infra-halter sclerite absent.
Leg: brown, setation predominantly black; pro, mes, and met coxa lightly grey pubescent, black setose; met trochanter setose medially; femur brown, met femur ± cylindrical only slightly wider than pro and mes femur, in distal ½ macrosetose, 1 antero-ventral and 1 postero-ventral row of macrosetae, postero-ventrally long brown setose; pro and mes tibia laterally arched, met tibia straight, met tibia cylindrical, ventral keel absent, postero-laterally regular setose; pro and mes tarsomere 1 longer than tarsomere 2, but less than combined length of tarsomeres 2–3, met tarsomere 1 as long as combined length of tarsomeres 2–3; pulvillus well-developed, as long as well-developed claw, and as wide as base of claw; setiform empodium absent.
Wing: length = 16.7–20.8 mm; light brown stained, especially along veins, distal ¼ and posterior margin unstained, veins brown, microtrichia absent; cells r1, r4, r5, m3, + cup closed except r5 open; C well-developed, around entire wing; R4 terminates in R1; R5 terminates in R1; stump vein (R3) at base of R4 present, long but not reaching R2; R4 and R5 ± parallel medially; r-m distinct, R4 + 5 and M1 apart, connected by crossvein; M1 curves slightly anteriorly at r-m, M1 (or M1 + M2) terminates in C; M4 and CuA split proximally to m-cu (cell m3 narrow proximally); M3 + M4 terminate together in C (reaching wing margin); CuP straight, cell cup wide, CuP and wing margin further apart proximally than distally; alula well-developed, very large and partly overlapping with scutellum medially; halter brown.
Abdomen: brown to metallic bluish-black; setation comprised of scattered black setae, surface entirely smooth; T1–7 brown with narrow yellow posterior margin; T1 long brown to black setose, T2–7 short black setose; T1 lightly grey pubescent, T2–7 apubescent; S1 brown with light brown posterior margin, S2–6 brown with narrow yellow posterior margin; S1 asetose, S2–7 sparsely black setose; S apubescent; T2–4 parallel-sided and not constricted waist-like; bullae on T2 black, transversely elongate, surface entirely smooth, T2 surface anterior to bullae smooth.
Type locality: Argentina: Catamarca: Belén, 27◦ 38Ɩ 59ƖƖS 067◦ 01Ɩ 58ƖƖW (−27.64972 −67.03278).
Material examined: Argentina: Catamarca: 1M * Belén, 27◦38Ɩ59ƖƖS 067◦01Ɩ 58ƖƖW, −27.64972 −67.03278, 1975-11-25, Bohart, R. (AAM-005629, Holotype, CSCA); 1F * 1M * Belén, 6 km S, 27◦43Ɩ47ƖƖS 067◦01Ɩ15ƖƖW, −27.72972 −67.02083, 1975-11- 25, Stange, L. (M* AAM-002714, F* AAM-002718, Paratypes, IMLA); 1F * 4M * Belén, 6 km S, 1975-11-25, Stange, L. (MZSP- MZ003838–MZSP-MZ003841, MZSP-MZ003846, Paratypes, MZSP); Salta: 1M * Cafayate, 22 km N, 26◦ 02Ɩ 56ƖƖS 065◦54Ɩ01ƖƖW, −26.04889 −65.90028, 1578 m, 2003-11-13, white sand dunes, Irwin, M., Parker, F. (CASENT8380021–CASENT8380022, Paratypes, CAS); 1M * Cafayate, 26◦04Ɩ 06ƖƖS 065◦58Ɩ29ƖƖW, −26.06833 −65.97472, 1700 m, 1991-01-05, dune, Osten, T. (AAM-003864, Paratype, SMNS); 1M * Cafayate, 1993-11-14, Rozen, J., Rozen, B. (AAM-004054, Paratype, AMNH); Paraguay: San Pedro: 1M * Carumbé, 24◦08Ɩ 46ƖƖS 056◦37Ɩ30ƖƖW, −23.95 −56.6, 1973- 01-10 – 1973-02-10, Golbach, R. (MZSP-MZ003843, Paratype, MZSP).
Distribution and biodiversity hotspot: Western Argentina (Catamarca and Salta) and Paraguay (San Pedro) (Fig. 27). The geographic co-ordinates for Carumbé (Paraguay) are taken from GBIF record 416921317. The easternmost distribution of this species in Paraguay overlaps with the Atlantic Forest biodiversity hotspot.
Remarks: Sexual dimorphism is minimal with only slight differences in color of sclerites or setae. The two females studied have a wing length of 19.3–19.4 mm while males have a wing length of 16.7–20.8 mm. Two specimens (AAM-003864, AAM-002715) lack the postero-median grey pubescent spot directly anterior to the scutellum. We believe that these two specimens belong to P. phalaros sp. nov. though. The disjunct distribution of P. phalaros sp. nov. in mid-elevation western Argentina and low-elevation Paraguay is interesting. We have no reason to believe that the Paraguayan specimen (AAM-002720) is mislabeled as a search on the internet reveals that other insects have been collected by R. Golbach in Carumbé in the 1970s (Google search) providing evidence that the specimen is correctly labeled.
description: Published as part of Castillo, Stephanie & Dikow, Torsten, 2017, Taxonomic revision of Plyomydas Wilcox & Papavero, 1971 with the description of two new species and its transfer to Mydinae (Insecta: Diptera: Mydidae), pp. 192-202 in Revista Brasileira de Entomologia 61 (2) on pages 197-200, DOI: 10.1016/j.rbe.2017.03.002, http://zenodo.org/record/10073509