Rasnitsynala sigambrorum, Zessin, Wolfgang, Brauckmann, Carsten & Groening, Elke, 2011

Zessin, Wolfgang, Brauckmann, Carsten & Groening, Elke, 2011, Rasnitsynala sigambrorum gen. et sp. n., a small odonatopterid (" Eomeganisoptera ", " Erasipteridae ") from the early Late Carboniferous of Hagen-Vorhalle (Germany), ZooKeys 130, pp. 57-66 : 59-60

Rasnitsynala sigambrorum sp. n. Figs 2-3

Zessin 2008a: 5 - kleine, neue unbeschriebene Art von Vorhalle (= small, yet undescribed new species from Vorhalle)

Holotype.

Former Sippel collection no. 182 A and B, now collection of the LWL-Museum für Naturkunde, Westfälisches Landesmuseum mit Planetarium in Münster (Germany), positive imprint: no. WMf.N P27781, negative imprint: no. WMf.N N3182B.

Type locality.

Abandoned brickyard quarry in Hagen-Vorhalle, North Rhine-Westphalia, Germany (topographic map 1: 25,000 sheet no. 4610 Hagen/Westfalen; 51°22.88'N; 007°26.77'E, ~115 m a.s.l.).

Stratum typicum.

Early Late Carboniferous (Early Pennsylvanian: late Namurian B, late Marsdenian), Ziegelschiefer Formation.

Diagnosis.

Thus far the smallest species of the " Erasipteridae " with the following main characters: Mesothoracic wing: (i) Length: 27 mm; (ii) anterior margin very slightly convex; (iii) ScP– very long, nearly reaching apex; (iv) subcostal area (Sc area) distally very narrow between ScP– and “PC/CA+/CP–/ScA+”; (v) AA1+ short, forming an angle of about 45° with Cu and CuA+; (vi) basal parts of CuA+ and CuP– rather long; (vii) basal intercubital area (ICu area) a relatively high triangle with its point downwards; (viii) kink between CuA+ and CuP– very short. Metathoracic wing: (i) Length: 22 mm; (ii) anterior margin very slightly convex. Body: (i) Preserved length (without head and posterior 3 abdominal segments): 24.5 mm, estimated total length: 32 mm; (ii) abdominal segments narrow and long.

Preservation.

The rather well preserved fossil lies in dorsal view. The head with antennae, legs, the posterior three abdominal segments and the left wings are lacking as well as the posterior regions of the right wings. Nevertheless, the preserved parts of the right wings clearly exhibit the main diagnostic features. The original corrugation is nearly completely flattened by tectonic processes but can be reconstructed by comparison with the characters of the ground plan ( Kukalová-Peck 2009). The body is compressed, too, and a part of the thoracic segments seems to have been split off. Possibly the right mesothoracic wing was basally disconnected.

Measurements (in mm).

(i) Length of mesothoracic wing, 27; (ii) length of metathoracic wing, 22; (iii) preserved length of body (without posterior three abdominal segments), 24.5, estimated total length, 32.

Description.

Mesothoracic wing: Anterior margin very slightly convex; ScP– very long, nearly reaching apex; subcostal area (Sc area) distally very narrow between ScP– and complex PC/CA+/ CP– /ScA+; AA1+ short, forming an angle of about 45° with Cu and CuA+; basal parts of CuA+ and CuP– rather long; basal intercubital area (ICu area) resembling a relatively high triangle with its point downwards; kink between CuA+ and CuP– very short. Metathoracic wing: Anterior margin very slightly convex, nearly straight. Body: Abdominal segments slender and long.

Etymology.

After the Latin name of the Germanic tribe Sigambri (or Sugambri) who inhabited the type region of the species.

Discussion.

With a wing-span of about 55mm, Rasnitsynala sigambrorum gen. et sp. n. represents the smallest species known to date of the presumably paraphyletic " Erasipteridae ". It shows some characters already known from the very plesiomorphic Geroptera : Eugeropteridae (metathoracic wing of Eugeropteron lunatum Riek in Riek & Kukalová-Peck, 1984) or Meganisoptera : Aulertupidae ( Aulertupus tembrocki ), e.g. (i) the morphology of the intercubital area (ICu area) and (ii) the course of AA1+. The abdominal morphology is unknown in most Palaeozoic Odonatoptera and cannot be compered. In Rasnitsynala sigambrorum gen. et sp. n. it is extremely slender and longer than the wings. It is even relatively longer and narrower than in the contemporaneous Namurotypus sippeli and Erasipteroides valentini but seems to be similar in Zessinella siope , again of the same age and locality. This character is common in several Recent Zygoptera . It demonstrates that the basic ground plan of Odonatoptera was already established in the very early phase of their evolution, presumably long before the Namurian B (about 319 m.y. ago).