Ilyobius nubila ( Navas )

Liu, Xingyue, Hayashi, Fumio & Yang, Ding, 2015, Taxonomic notes of the Neotropical alderfly genus Ilyobius Enderlein, 1910 (Megaloptera, Sialidae), with description of a new species, Deutsche Entomologische Zeitschrift 62 (1), pp. 55-63 : 55

Taxon classification Animalia Megaloptera Sialidae

Ilyobius nubila ( Navas) Figs 4, 12-14, 15

Protosialis nubila Navás, 1933: 36. Type locality: Brazil ( São Paulo).

Protosialis brasiliensis Navás, 1936: 725. Type locality: Brazil ( São Paulo: Ipiranga).

Re-description.

Female. Body length 8.0 mm; forewing length 10.0 mm, hindwing length 8.3 mm.

Head (Figs 4, 12) black, slightly paler around epicranial suture, with dense yellowish pilosity; a pair of dark orange areas posteriorly expanded from entire inner margins of compound eyes; vertex with raised scars. Compound eyes blackish brown. Antennae with scape and pedicel blackish brown, flagellum lost. Mouthparts black.

Thorax (Figs 4, 12) black throughout. Legs yellowish brown, bearing dense brownish setae; tarsal claws reddish brown. Wings smoky brown, with brownish veins. Forewing about 3.5 times as long as wide; costal area proximally distinctly dilated, with five distinct crossveins; sc-r present; Rs with two simple branches; MA with two simple branches; MP proximally fused with CuA, having simple anterior branch and bifurcate posterior branch; CuA bifurcated, CuP simple; 1A simple, 2A with two simple branches, 3A simple; three r-rs present. Hindwing slightly broader than forewing, about 3.0 times as long as wide; costal area with two distinct crossveins, branching condition of longitudinal veins mostly same as that of forewing, except for MP having two simple branches; MA proximally leaving a short oblique veinlet fused with MP; M separated from R.

Abdomen black. Sternite 7 (Figs 13-14) broad, with posterior margin roundly prominent medially. Fused gonocoxites 8 (Figs 13-14) rather small, sparsely setose, fused at anterior margin of gonapophyses 8; gonapophyses 8 (Fig. 14) composed of a strongly sclerotized plate, which is ventrally depressed and strongly widened on posterior half, with a broadly arched posterior incision, and a pair of broadly semicircular and a pair of tiny, transparent, membranous plates. Tergite 9 laterally separating into narrowly subtrapezoidal dorsal region and narrowly subtriangular ventral region. Gonocoxite 9 (Fig. 13) broadly valvate, arcuately margined ventrad, posteriorly with a small gonostylus 9 at tip. Ectoprocts (Fig. 13) short, ovoid.

Male. Unknown.

Type material.

Holotype ♀, "Malto Go-vuros? [unrecognizable handwritten words], Melzer/Brasil - S[ ão]. Paulo, Est[at]. S[ ão]. Paulo, 20.XI.1927 [collecting data on opposite side of the label]/ Protosialis nubila Nav[ ás]., P. Navás S.J. det./Holotypus" (SDEI).

Distribution.

Brazil ( São Paulo).

Remarks.

Protosialis brasiliensis Navás, 1936 was treated to be a junior synonym of Ilyobius nubila by Liu et al. (2015), but a re-description and a detailed comparison of these two species was not provided in that paper. The evidence for synonymizing these two species is: 1) the same cephalic color patterns with broad black area approaching the compound eyes, 2) the same black pronotum, 3) the same wing shape, which is narrowed with distinctly dilated costal area; 4) the same distribution area. The type locality of Ilyobius nubila was cited to be in the Mato Grosso State of Brazil (Oswald 2014). This record is actually from a very unclear and unrecognizable handwritten label of the holotype of Ilyobius nubila . However, the opposite side of this collecting label includes some printed words "Brasil - S. Paulo, Est. S. Paulo" and a possible collecting date “20.XI.1927”, which have never been mentioned in the original description ( Navás 1933). Therefore, we cannot exclude the possibility that the holotype of Ilyobius nubila was collected from São Paulo, where this species occurs, based on the distribution record of Protosialis brasiliensis (the junior synonym of Ilyobius nubila ).

This species appears to be closely related to another Brazilian species, Ilyobius hauseri (Contreras-Ramos, Fiorentin & Urakami, 2005), by having similar cephalic color patterns with a longitudinal median black stripe, the black pronotum, and the narrow forewings with distinctly dilated costal area. However, Ilyobius nubila can be distinguished from Ilyobius hauseri by the broader cephalic black stripe and the posteriorly broadened female gonapophyses 8 with a broad arcutate posterior notch. In Ilyobius hauseri , the cephalic black stripe is relatively narrow and not approaching the compound eyes, and the female gonapophysis 8 is convex posteriad without any posterior notch.