Gastrioceras spp.

Text-fig. 4. Taphonomic features of the studied localities of ammonoids. a: Sandstone slab with fragmentary remains of productid and spiriferid brachiopods, orthocerids, coiled nautiloids and ammonoids (stratigraphic level No. 3). b: Shell debris cluster and fragment of crushed ammonoid conch (stratigraphic level No. 1). c: Epibionts on the surface of an ammonoid conch (stratigraphic level No. 5). d: Cluster of bivalves, gastropods and cephalopods remains in a siderite nodule (stratigraphic level No. 5). e: Fragment of an ammonoid conch (stratigraphic level No. 3). f: Fragment of an ammonoid conch (?) with terminal aperture and brachiopod valve (stratigraphic level No. 3). g: Specimen of?Anthracoceratites sp. with conch injuries (shown by arrows) (stratigraphic level No. 8). h, i: Bioerosion trace fossils Cyclopuncta girtyi ELIAS, 1958 on the fragments of cephalopod conchs (stratigraphic level No. 5). j: Limonitized conchs of the ammonoid (stratigraphic level No. 7). k: Fragment of an ammonoid conch (stratigraphic level No. 5). Scale bars 10 mm.

Text-fig. 10. Gastrioceras sp., lateral view (a), ventral view (b– d); a, b – specimen IGSU-4/6390, c – specimen IGSU-4/6390a, d – specimen IGSU-4/6390b. Scale bar 10 mm.

Text-fig. 4. Taphonomic features of the studied localities of ammonoids. a: Sandstone slab with fragmentary remains of productid and spiriferid brachiopods, orthocerids, coiled nautiloids and ammonoids (stratigraphic level No. 3). b: Shell debris cluster and fragment of crushed ammonoid conch (stratigraphic level No. 1). c: Epibionts on the surface of an ammonoid conch (stratigraphic level No. 5). d: Cluster of bivalves, gastropods and cephalopods remains in a siderite nodule (stratigraphic level No. 5). e: Fragment of an ammonoid conch (stratigraphic level No. 3). f: Fragment of an ammonoid conch (?) with terminal aperture and brachiopod valve (stratigraphic level No. 3). g: Specimen of?Anthracoceratites sp. with conch injuries (shown by arrows) (stratigraphic level No. 8). h, i: Bioerosion trace fossils Cyclopuncta girtyi ELIAS, 1958 on the fragments of cephalopod conchs (stratigraphic level No. 5). j: Limonitized conchs of the ammonoid (stratigraphic level No. 7). k: Fragment of an ammonoid conch (stratigraphic level No. 5). Scale bars 10 mm.

Text-fig. 6. Stratigraphic distribution of ammonoids in the Mospyne Formation. The lithological symbols are the same as in Text-fig. 2.