Plyomydas adelphe, Castillo & Dikow, 2017

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), Revista Brasileira de Entomologia 61 (2), pp. 192-202 : 194-196

Plyomydas adelphe sp. nov.

ZooBank 27B0A7A0-0548-4F53-97AF-BCFD98B057FC

Figs. 1–11 , 27

Diagnosis: The species is distinguished from congeners by the scutal pubescence pattern with only three pairs of grey pubescent spots ( Figs. 1 and 5 ) and the absence of a grey pubescent stripe on the posterior anepisternum ( Fig. 2 ).

Etymology: From Greek adelphe = sister, referring to overall morphological similarity to Plyomydas phalaros sp. nov.

Description: Head: black, 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 black, frons brown, ocp setae yellow, pocl macrosetae black; 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: black or 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 antero-paramedially, 2 pairs laterally (1 at transverse suture, 1 postero-laterally), scutal setation comprised of pubescent spots long black or brown setose; dc setae pre- and postsuturally black, acr setae absent, lateral scutal setae black or brown, npl setae 0, spal setae 0, pal setae 0; antepronotum dorso-medially smooth (without any indentation); postpronotal lobe brown to black, lightly grey pubescent; proepisternum, lateral postpronotum, and postpronotal lobe long black setose; scutellum lightly 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 apubescent, 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: light brown to brown, setation predominantly black; pro, mes, and met coxa lightly grey pubescent, black setose; met trochanter setose medially; femur black or 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 welldeveloped claw, and as wide as base of claw; setiform empodium absent.

Wing: length = 15.2–18.5 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: Mendoza: Rt. 142 at Mendoza River, 32◦35Ɩ 29ƖƖS 068◦17Ɩ28ƖƖW (−32.59139 −68.29111).

Material examined: Argentina: Mendoza: 1M * Rt. 142 at Mendoza River, 21 km NE Costa de Araujo , 32◦35Ɩ 29ƖƖS 068◦17Ɩ 28ƖƖW, −32.59139 −68.29111, 585 m, 2015-12-04, Steiner, W., Swearingen, J. ( USNMENT01242234 , Holotype, IADIZA) ; 1F * Mendoza, 35◦52Ɩ 00ƖƖS 068◦49Ɩ00ƖƖW, −32.88944 −68.84583, 1907-00-00 ( AAM-004053 , Paratype, ZSMC) ; La Rioja: 1M * Cuesta de Miranda , 29◦19Ɩ 00ƖƖS 067◦39Ɩ 00ƖƖW, −29.31667 −67.65, 1700 m, 1977-11-29, Willink, A., Fidalgo ( AAM-002719 , Paratype, MZSP) .

Distribution and biodiversity hotspot: Western Argentina in the provinces of La Rioja and Mendoza ( Fig. 27 ). Not known to occur in any biodiversity hotspot.

Remarks: Sexual dimorphism is minimal. Based on the three known specimens, females are larger (wing length 18.5 mm in the sole female paratype, 15.2–16.6 mm in two males) and dimorphism only occurs in color of legs and sclerites. The holotype was collected in low flat mesquite desert and dry riverbed.

Figures

Figs. 1–6. Photographs of male and female Plyomydas adelphe sp. nov.: (1) M* holotype (USNMENT01242234), dorsal (Morphbank #860756); (2) same, lateral (#860758); (3) same, head anterior (#860760); (4) F* paratype (AAM-004053), head anterior (#860784); (5) same, dorsal (#860780); (6) same, lateral (#860782). Scale line= 5 mm.

Figs. 7–11. Male and female terminalia of Plyomydas adelphe sp. nov.: (1) M* paratype (MZSP-MZ003844), lateral (posterior gonocoxal processes highlighted in grey); (2) same, dorsal; (3) same, ventral; (4) F* paratype (AAM-004053), dorsal; (5) same, ventral. Scale line= 1 mm, setation omitted.Figshare DOI 10.6084/m9.figshare.4490462.

Fig. 27. Map of South America with elevational relief and biodiversity hotspots (in grey) showing distribution of Plyomydas adelphe sp. nov. (orange), P. peruviensis (yellow), and P. phalaros sp. nov. (blue). Type localities plotted with square symbols. Map data available in Google Earth KML file 6102and also through GBIF (data-set 7f2de377-9f9f-4276-b0b8-5c792b499223, DOI 10.15468/tiymja).