Mesoptilus dolloi ( Lameere, 1917 )

Guan, Zhaoying, Prokop, Jakub, Roques, Patrick, Lapeyrie, Jean & Nel, André, 2016, Revision of the enigmatic insect family Anthracoptilidae enlightens the evolution of Palaeozoic stem-dictyopterans, Acta Palaeontologica Polonica 61 (1), pp. 71-87 : 76-77

Mesoptilus dolloi ( Lameere, 1917)

Fig. 3 .

Holotype: MNHN R51159, imprint of prothorax, forewings and fragmentary legs.

Type locality: Commentry Basin, Allier department, France.

Type horizon: Stephanian, Carboniferous (= Gzhelian, Upper Pennsylvanian).

Material.— Type material only.

Emended diagnosis.—Forewing anterior branches of CuA strongly approximate at their bases, with first one distant from m-cua.

Description.—Some details of forewing venation have been neglected by Béthoux and Wieland (2009), so we prefer to provide a redescription of this taxon. An imprint of prothorax with nearly complete right wing and base of left wing, and some legs attached.

Thorax poorly preserved, 6.0 mm wide; fore femur 23 mm long, 1.7 mm wide; tibia more than 8.0 mm long, 0.9 mm wide, with a series of strong curved spines along inner margin, 0.3 mm long. Hind leg with strong femora and with tibia 1.6 mm wide, armed with an outer series of strong spines; a hind wing partly preserved; a complete forewing and basal half of the other one attached to thorax.

Forewing with anterior margin partly missing in apical part, and posterior base part missing due to covering by a leg; wing 29.6 mm long, 8.9 mm wide; straight, concave ScP with several anterior branches reaching costal margin, each subdivided; area between ScP and costal margin with numerous crossveins and veinlets, 1.5 mm wide; ScP parallel to radius, 0.7 mm apart, ending on RA 17.5 mm from wing base; radial stem straight, with RP separating from RA 7.9 mm from wing base; RA strongly convex, straight and simple, ending 3.1 mm from wing apex; slightly concave RP posteriorly pectinate, with eight main branches, resulting into 11 branches ending on wing margin; RP and median vein separated but approximate with a short crossvein between them 5.6 mm from wing base; median vein slightly more convex than RP, divided into three straight and simple branches; presence of a brace m-cua between median vein and CuA; strongly convex CuA anteriorly pectinate with four main branches distinctly less convex than main stem of CuA, resulting into seven branches ending on wing margin; CuA separating from CuP 2.3 mm from wing base; concave CuP simple, curved with numerous crossveins between it and CuA in a 1.4 mm wide area, this zone being partly covered by a leg in one wing; area between CuP and posterior wing margin 2.5 mm wide; five visible weakly curved main branches of anal veins, a net of crossveins present in between, but poorly preserved; posterior part of anal area and wing base (possible jugal area) missing; a dense net of rather straight crossveins between branches of all main veins, except in area between CuA and CuP, between C and ScP, and anal area where nets of more irregular cells are present.

Stratigraphic and geographic range.—Gzhelian (Upper Pennsylvanian), France.

Figures

Fig. 3. Forewing of anthracoptilid insect Mesoptilus dolloi (Lameere, 1917) from Stephanian of Commentry Basin, France, holotype R51159, photograph A), line drawing (B).