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Fig. 13 in The Changhsingian (Late Permian) ammonoids from Baghuk Mountain (Central Iran)

Fig. 13. Cross section of a specimen of Paratirolites sp. from Baghuk Mountain, MB.C.22215; note the different states of preservation of shell walls and septa: a = recrystallized but rather well-preserved shell wall and septa preferably in the mid-dorsal portion of the ammonoid conch; b = dissolved shell wall but sharp demarcation of the ammonoid's internal mould from the sediment at the lower side of the ammonoid conch; c = dissolved shell wall and nearly continuous transition from the ammonoid's internal mould towards the sediment on the upper side of the ammonoid conch (from Leda et al. 2014).

Fig. 12 in The Changhsingian (Late Permian) ammonoids from Baghuk Mountain (Central Iran)

Fig. 12. Mass occurrence of small ammonoids of the genus Arasella Korn in Ghaderi et al., 2014 on the bedding surface at the base of the topmost 5 cm limestone bed, Baghuk Mountain section H. Scale bar units = 10 mm.

Fig. 5 in The Changhsingian (Late Permian) ammonoids from Baghuk Mountain (Central Iran)

Fig. 5. The stratigraphic occurrence of the ammonoid species in the upper part of the Hambast Formation at Baghuk Mountain 1 section. EH = extinction horizon.

Fig. 9 in The Changhsingian (Late Permian) ammonoids from Baghuk Mountain (Central Iran)

Fig. 9. The stratigraphic occurrence of the ammonoid species in the upper part of the Hambast Formation at Baghuk Mountain H section. EH = extinction horizon.

Fig. 4 in The Changhsingian (Late Permian) ammonoids from Baghuk Mountain (Central Iran)

Fig. 4. The upper portion of the Hambast Formation (Paratirolites Limestone equivalent) in Baghuk Mountain 1 section.

Fig. 3 in The Changhsingian (Late Permian) ammonoids from Baghuk Mountain (Central Iran)

Fig. 3. Four selected columnar sections of the upper part of the Hambast Formation (Paratirolites Limestone equivalent) at Baghuk Mountain with their ammonoid zonation.

Fig. 8 in The Changhsingian (Late Permian) ammonoids from Baghuk Mountain (Central Iran)

Fig. 8. The stratigraphic occurrence of the ammonoid species in the upper part of the Hambast Formation at Baghuk Mountain G section. EH = extinction horizon.

Fig. 25 in The Changhsingian (Late Permian) ammonoids from Baghuk Mountain (Central Iran)

Fig. 25 (next page). Paratirolites lanceolobatus Korn & Hairapetian sp. nov. A–E. Lateral and dorsal views. A. Holotype MB.C.29769, section B, float. B. Paratype MB.C.29751, section 1, float. C. Paratype MB.C.29770, section E, -3.30 m. D. Paratype MB.C.29752, section A, float. E–H. Suture lines. E. Holotype MB.C.29769, at 13.5 mm wh. F. Paratype MB.C.29751, at 11.2 mm wh. G. Paratype MB.C.29757, at 11.2 mm wh. H. Paratype MB.C.29770, at 11.1 mm wh. I. Whorl profile proportions. Abbreviations: see Material and methods. Scale bar units = 1 mm.

Fig. 9 in The tornoceratid ammonoids from the Roteisenstein Formation of Dillenburg (Cephalopoda, Ammonoidea)

Fig. 9. Paucitornoceras paucistriatum (d'Archiac & de Verneuil, 1842); MB.C.30414 (Koch Coll.) from Oberscheld. Scale bar units = 1 mm.

Fig. 7 in The tornoceratid ammonoids from the Roteisenstein Formation of Dillenburg (Cephalopoda, Ammonoidea)

Fig. 7. Epitornoceras mithracoides (Frech, 1888), specimens from the Volpertseiche Mine near Oberscheld (both Koch Coll.). A. Lectotype (MB.C.469). B. Suture line of lectotype (MB.C.469); at dm = 43.5 mm; ww = 15.0 mm; wh = 25.5 mm. C. Paralectotype (MB.C.470). Scale bar units = 1 mm.

Fig. 8 in The tornoceratid ammonoids from the Roteisenstein Formation of Dillenburg (Cephalopoda, Ammonoidea)

Fig. 8. Lentitornoceras materni gen. et sp. nov., holotype (MB.C.30413; Lotz 1901–1902 Coll.) from Oberscheld. A. Ventral view, lateral view and dorsal projection. B. Suture line; at dm = 26.0 mm; ww = 6.4 mm; wh = 15.2 mm. C. Growth line course; at dm = 26.0 mm; ww = 6.4 mm; wh = 15.2 mm. Scale bar units = 1 mm.

Fig. 4 in The tornoceratid ammonoids from the Roteisenstein Formation of Dillenburg (Cephalopoda, Ammonoidea)

Fig. 4. Tornoceras typus (Sandberger & Sandberger, 1851), reproduction of the lectotype illustrations by Sandberger & Sandberger (1850–1856, pl. 10 fig. 14) and the photography by M.R. House in Becker (1993, pl. 3 figs 1–2). Scale bar units = 1 mm.

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Fig. 5. Tornoceras frechi Wedekind, 1918. A in The tornoceratid ammonoids from the Roteisenstein Formation of Dillenburg (Cephalopoda, Ammonoidea)

Fig. 5. Tornoceras frechi Wedekind, 1918. A. Specimen MB.C.834 (Beyrich Coll.) from Sessacker near Oberscheld. B. Suture line of specimen MB.C.834 (Beyrich Coll.); at ww = 4.5 mm, wh = 5.5 mm. C. Specimen MB.C.30411 (Dannenberg Coll.) from Sessacker near Oberscheld.D. Specimen MB.C.4490 from Sessacker Oberscheld. Scale bar units = 1 mm.

Fig. 6 in The tornoceratid ammonoids from the Roteisenstein Formation of Dillenburg (Cephalopoda, Ammonoidea)

Fig. 6. Epitornoceras mithracoides (Frech, 1888), reproduction in original size of the illustration of the type material; paralectotype (MB.C.470) and lectotype (MB.C.469) by Frech (1888).

Fig. 2 in The tornoceratid ammonoids from the Roteisenstein Formation of Dillenburg (Cephalopoda, Ammonoidea)

Fig. 2. Givetian and Frasnian ammonoid stratigraphy (after Becker & House 2000), probable extent of the Red Ironstone of Dillenburg and probable position of the ammonoid species described here.

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Geographic and temporal morphological stasis in the latest Cretaceous ammonoid Discoscaphites iris from the U.S. Gulf and Atlantic Coastal Plains

We examine temporal and spatial variation in morphology of the ammonoid cephalopod Discoscaphites iris using a large dataset from multiple localities in the Late Cretaceous (Maastrichtian) of the United States Gulf and Atlantic Coastal Plains, spanning a distance of 2000 km along the paleoshoreline. Our results suggest that the fossil record of D. iris is consistent with no within species net accumulation of phyletic evolutionary change across morphological traits or the lifetime of this species. Correlations between some traits and paleoenvironmental conditions as well as changes in the coefficient of variation may support limited population-scale ecophenotypic plasticity, however where stratigraphic data are available, no directional changes in morphology occur prior to the Cretaceous/Paleogene (K/Pg) boundary. This is consistent with models of 'dynamic' evolutionary stasis. Combined with knowledge of life history traits and paleoecology of scaphitid ammonoids, specifically a short planktonic phase after hatching followed by transition to a nektobenthic adult stage, these data suggest that scaphitids had significant potential for rapid morphological change in conjunction with limited dispersal capacity. It is therefore likely that evolutionary mode in the Scaphitidae (and potentially across the broader ammonoid clade) follows a model of cladogenesis wherein a dynamic morphological stasis is periodically interrupted by more substantial evolutionary change at speciation events. Finally, the lack of temporal changes in our data suggest that global environmental changes (such as those possibly related to the emplacement of the Deccan Traps Large Igneous Province) had a limited effect on the morphology of North American ammonoid faunas during the latest Cretaceous prior to the K/Pg mass extinction event.

Fig. 17 in The early gephuroceratid ammonoids from the Roteisenstein Formation of Dillenburg (Cephalopoda, Ammonoidea)

Fig. 17. Koenenites lamellosus (Sandberger & Sandberger, 1851). A. Specimen MB.C.22184 (Koch Coll.) from Oberscheld (Anna Mine). B. Specimen MB.C.22183 (Dannenberg Coll.) from Oberscheld (Rinkenbach Mine). C. Specimen MB.C.4306.1 (Koch Coll.) from Oberscheld (Anna Mine). D. Specimen MB.C.4306.2 (Koch Coll.) from Oberscheld (Anna Mine). E. Specimen MB.C.4306.3 (Koch Coll.) from Oberscheld (Anna Mine). Scale bar units = 1 mm.

Fig. 14 in The early gephuroceratid ammonoids from the Roteisenstein Formation of Dillenburg (Cephalopoda, Ammonoidea)

Fig. 14. Darkaoceras galeatum (Matern, 1931). A. Suture line of specimen MB.C.3633 (Ahlburg Coll.) from Oberscheld (Königszug Mine), at ww = 10.7 mm, wh = 16.5 mm. B–E. Ontogenetic trajectories of the cardinal conch parameters. Scale bar units = 1 mm.

Fig. 8 in The early gephuroceratid ammonoids from the Roteisenstein Formation of Dillenburg (Cephalopoda, Ammonoidea)

Fig. 8. Ponticeras aequabile (Beyrich, 1837). A. Specimen MB.C.4291 (Koch Coll.) from Oberscheld. B. Specimen MB.C.4290 (Kauth Coll.) from Oberscheld. C. Specimen MB.C.5576 (Erbreich Coll.) from Oberscheld. D. Lectotype MB.C.4289.1 (Beyrich 1835 Coll.) from Oberscheld (Sessacker). E. Specimen MB.C.4289.2 (Erbreich Coll.) from Oberscheld. Scale bar units = 1 mm.

Fig. 21 in The early gephuroceratid ammonoids from the Roteisenstein Formation of Dillenburg (Cephalopoda, Ammonoidea)

Fig. 21. Acanthoclymenia planorbis (Sandberger & Sandberger, 1851).A. Lectotype 46a in the Wiesbaden collection from Oberscheld; photograph and reproduction of the figure of Sandberger & Sandberger (1850–1856: pl. 9 fig. 3a). B. Paratype 46b in the Wiesbaden collection from Oberscheld; photograph and reproduction of the figure of Sandberger & Sandberger (1850–1856: pl. 9 fig. 3). C. Probably lost specimen; photograph and reproduction of the figure of Sandberger & Sandberger (1850–1856: pl. 9 fig. 3d, e). Scale bar units = 1 mm.