Strephocladus permianus, Guan & Prokop & Roques & Lapeyrie & Nel, 2016

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 : 74-76

Strephocladus permianus sp. nov.

Fig. 2 .

Etymology: Named after the Permian period.

Holotype: Ld LAP 310 A, B (imprint and counterimprint).

Type locality: Lodève Basin , Languedoc, France.

Type horizon: Salagou Formation, Mérifons Member , Guadalupian middle Permian ).

Material. — Type material only.

Diagnosis.—Forewing characters only. Three branches of RP; three branches of median vein; median vein and RP strongly approximate but not touching; costal margin straight.

Description.—Single wing with extreme base missing and basal part of posterior margin strongly curved, 28.6 mm long, 7.4 mm wide; simple, straight, concave ScP closely parallel to Radius, 0.28 mm apart, ending on RA 16.7 mm from wing base; area between ScP and costal margin 0.9 mm wide, apparently without crossveins or veinlets, even if some faint traces are weakly visible, that could correspond to veinlets between ScP and C; radial stem straight, with RP separating from RA 9.3 mm from wing base; RA straight, but with two curved posterior branches near wing apex; apex of main branch of RA 4.1 mm from wing apex; slightly concave RP with three posterior simple branches; RP strongly approximating median vein near its bases, with a cell between them; slightly concave median vein touching CuA in one point 5.6 mm from wing base; 1.2 mm distally, median stem divided into a first simple posterior branch, second branch of M divided into two simple branches 4.0 mm distally; convex CuA anteriorly pectinate with five parallel simple branches less convex than main stem of CuA; concave CuP simple, weakly curved with a rather narrow area between it and CuA, 0.8 mm wide; basal part of CuA appearing as a weak vein rather long, 3.0 mm long, between its distal part and CuP, but CuA and CuP emerging from a common stem; area between CuP and posterior wing margin 1.3 mm wide; first anal vein convex, simple, nearly straight; remnants of a second anal vein visible but posterior part of anal area certainly missing; several simple crossveins are present between branches of M and RP, but generally rather poorly preserved; all branches of RP, M and CuA weakly curved and parallel.

Remarks.—The forewing of Strephocladus permianus sp. nov. is strongly similar to that of the Gzhelian (Late Pennsylvanian) Strephocladus subtilis ( Kliver, 1883) , revised by Carpenter (1966). They share the following potential apomorphies: branches of CuA, median vein and RP are parallel; CuA anteriorly pectinate with five branches; median vein and RP strongly approximate near base of RP; first branch of median vein close to CuA; ScP and R closely parallel with ScP ending on RA; CuP and first anal vein simple. Some differences between the two fossils are due to preservation problems, i.e., type wing of S. subtilis has veinlets in costal area while this zone seems to have no veins in the type specimen of S. permianus , apical part of wing of S. subtilis is missing so that it is impossible to determine if it has posterior branches of RA and the exact number of branches of median vein. More important differences are the presence of five branches of RP in S. subtilis instead of three in S. permianus ; presence of only two branches of median vein in S. subtilis instead of three in S. permianus ; median vein and RP touching in S. subtilis while they are only strongly approximate in S. permianus ; and costal margin with a weak but distinct curve near the wing base in S. subtilis while it is straight in S. permianus (see Waterlot 1934: pl. 20: 5). Thus, we consider that S. permianus belongs to a new species of the same genus Strephocladus .

Stratigraphic and geographic range.—Stephanian, Carboniferous (= Gzhelian, Upper Pennsylvanian)–Guadalupian, middle Permian), France and Germany.

Figures

Fig. 2. Forewing of anthracoptilid insect Strephocladus permianus sp. nov. from Guadalupian of Lodève Basin, France, holotype Ld LAP 310A, B, photographs of imprint and couterimprint (A, B), line drawing (C).