Matonia sp.

Moreau, Jean-David & Néraudeau, Didier, 2023, Amber and plants from the Upper Cretaceous of La Gripperie-Saint-Symphorien (Charente-Maritime, Western France), Comptes Rendus Palevol 22 (20), pp. 455-466 : 458-460

Matonia sp.

( Fig. 3 A-D)

MATERIAL. — Three specimens: IGR-23244 ; IGR-23245_A ; IGR-23246 .

DESCRIPTION

The material consists of fragments of fertile pinnules ( Fig.3 A-D). The largest specimen is 22 mm long and 4 mm wide. Pinnules are elongated, narrow and their margins are entire with parallel sides. Bases and apices of pinnules are not preserved. The midvein is strongly marked, forming a groove and is up 1 mm wide. Abaxial surface of pinnules displays secondary veins which are arranged opposite to alternate, forming an angle varying from 68 to 81° with the mid vein ( Fig. 3C, D). Abaxial surface of pinnules bears sunken, indusiate and circular to slightly oval sori ( Fig. 3A, B). Sori are 1.0- 1.3 mm in diameter and arranged in two rows close to the midvein. The distance between two neighbouring sori varies from 50 to 250 µm. Each indusium completely covers the sorus. Some indusia were detached and are preserved on the counter part of the specimen ( Fig. 3E). They display a coalified and highly fractured aspect. When the indusium is detached, the sorus shows a central mark which is 360-640 µm in diameter and that corresponds to the insertion of the stalk. Sporangia were not observed.

REMARKS

Gross morphology of fertile pinnules from La Gripperie-Saint-Symphorien is close to those of Phlebopteris Brongn., 1837 . However, the presence of indusia excludes this genus. As pointed by Nagalingum & Cantrill (2006), Matonidium Schenk, 1871 and Matonia are very similar. They mainly differ in the size of the indusium relative to the sorus. In Matonidium , the indusium partially covers the sorus, whereas in Matonia the indusium completely covers the sorus. Matonia is for the first time reported in the Cretaceous deposits from the Aquitaine Basin.