Ecdyonurus (Ecdyonurus) alaini Bauernfeind, 2020

Sartori, Michel & Bauernfeind, Ernst, 2020, Mayfly types and additional material (Insecta: Ephemeroptera) examined by F. - J. Pictet and A. - E. Pictet, housed in the Museums of Natural History of Geneva and Vienna, Revue suisse de Zoologie 127 (2), pp. 315-339 : 321

Ecdyonurus (Ecdyonurus) alaini Bauernfeind , sp. nov.

Fig. 4

Ecdyonurus forcipula . – Thomas, 1968b: 61. [misidentification, nec Ecdyonurus forcipula (F.-J. Pictet, 1843) ]

Type material: NMW; holotype, ♂ imago [reared], with legs, wings and genitalia on microscope slide and accompanied by its nymphal skin (in parts on slide); Neste d’Aure , app. 42°48’N 0°6’E, Massif de Néouvielle , 1600 m a.s.l., Hautes-Pyrénées , France; 10.7.1965; leg. A. Thomas. – NMW; paratype, 1 ♂ imago [reared], accompanied by its nymphal skin; same data as for holotype . – NMW; paratype, 1 ♂ imago [reared], accompanied by its nymphal skin; Aure Valley , 1200 m a.s.l., Hautes-Pyrénées , France; 30.7.1965; leg. A. Thomas.

Diagnosis: The new taxon is characterized by the following combination of characters: Imagines usually slightly smaller than those of E. venosus (fore wing length of holotype 14.0 mm), overall abdominal colouration more sombre, dull yellowish brown (in E. venosus more reddish), laterally a rather indistinct triangular brownish blotch in posterior half of abdominal segments 2-8 (frequently missing; a distinct triangular dark red to violet-black blotch in posterior half of abdominal segments in E. venosus ), posterior margin of forceps base almost straight (distinctly convex in E. venosus ) with (rarely without) low, broad and rounded lateral teeth. Penis lobes ( Fig. 4A ) slightly more massive, basal sclerite more broadly triangular, with few or no teeth along posterior margin (basal sclerite narrowly triangular, with strong teeth along posterior margin in E. venosus ), median titillators with a longitudinal row of inconspicuous subapical teeth or smooth (median titillators with a longitudinal row of strong subapical teeth in E. venosus ). Last instar larvae are characterized by rather strong, almost straight, apically broadly rounded pronotal processes ( Fig. 4B ) (apically bluntly pointed in E. venosus ) and comparatively weak and short lateral processes ( Fig. 4C ) (1/5 of segment length) on abdominal sterna 2-9 (strong and long, 1/3 of segment length in E. venosus ).

Figures

Fig. 4. Ecdyonurus (Ecdyonurus) alaini sp. nov. (A) Penis of holotype (dorsal view, slide preparation). Scale bar 0.2 mm. (B) Left half of pronotum (last larval instar exuvia of holotype; slide preparation). Scale bar 0.5 mm. (C) Abdominal sterna 4-6 (last larval instar exuvia of holotype; slide preparation). Scale bar 0.5 mm. Photos by Mag. H. Bruckner.