Microphon exiguus: an Aquatic Neotonic Kotlassiid Seymouriamorph (Reptiliomorph) From Permian Russia

New finds of Microphon exiguus (Seymouriamorpha, Kotlassiidae) in the Severodvinian beds of the Sukhona River Basin, Russia

Author:

Bulanov

Abstract:

New data on the morphology and ontogeny of the Permian kotlassiid Microphon exiguus Ivachnenko, 1983 (Tetrapoda, Seymouriamorpha), based on the collection from the Ust’e Strelny locality (Russia, Vologda Region; Severodvinian Regional Stage), are reported. At the definitive stage, M. exiguus retains the larval skull habitus (short preorbital region, a few marginal teeth, widely open posttemporal fenestra) and seismosensory grooves. These features, along with the reduced nasolacrimal duct, are indicative of an important role of pedomorphosis in the evolution of Severodvinian kotlassiids and, in particular, the genus Microphon, which should be regarded as a neotenic, permanently aquatic Permian amphibian.

French Lagerstätte Full of Discosauriscus

A new vertebrate Lagerstätte from the Lower Permian of France (Franchesse, Massif Central): palaeoenvironmental implications for the Bourbon-l'Archambault basin

Authors:

1. J.-Sébastien Steyer (a)

2. Sophie Sanchez (a,b)

3. Pierre J. Debriette (c)

4. Andrea M.F. Valli (d)

5. François Escuille (e)

6. Burkhard Pohl (e)

7. Roger-Paul Dechambre (f)

8. Renaud Vacant (a)

9. Christopher Spence (g)

10. Gaël de Ploëg (h)

Affiliations:

a. UMR 7207 CNRS, Centre de Recherche Paléobiodiversité et Paléoenvironnements, Département Histoire de la Terre, Muséum national d'Histoire naturelle, CP38, 8 rue Buffon, 75005 Paris, France

b. Subdepartment of Animal Evolution and Development, Department of Physiology and Developmental Biology, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18A, 752 36 Uppsala, Sweden

c. Le Champ Bernard, 03210 Gipcy, France

d. 78 Rue du Pont Ginguet, 03000 Moulins-sur-Allier, France

e. Eldonia Society, 9 Avenue des Portes Occitanes, 03800 Gannat, France

f. 13 Boulevard Saint-Marcel, 75013 Paris, France

g. 84 rue Oberkampf, 75011 Paris, France

h. Centre Permanent d'Initiatives pour l'Environnement, Ferme du Châteaux d'Aramont, 1 rue St Pierre, 60410 Verberie, France

Abstract:

A new vertebrate locality from the Lower Permian (Cisuralian) of the Bourbon-l'Archambault basin (Massif Central, France) is reported and its associated flora and fauna preliminarily described. This locality corresponds to a mass mortality assemblage deposited in an aquatic environment. Interestingly, it has yielded hundreds of exceptionally well preserved seymouriamorph specimens, all referred to Discosauriscus austriacus. This exquisite assemblage corresponds to the first seymouriamorph Lagerstätte and the first record of D. austriacus outside the Boskovice basin in Czechia. It enlarges the geographical distribution of the species during the Early Permian, and has new palaeoenvironmental implications regarding the Palaeozoic Bourbon-l'Archambault basin.