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Fig. 6 in Isometry in mesosaurs: Implications for growth patterns in early amniotes

Fig. 6. Length vs. width relationships in different hindlimb bones bones (A, femur; B, fibula; C, tibia; D, metatarsal; E, astragalus; F, calcaneum) of Mesosaurus tenuidens Gervais, 1865. The measured bone and the measurements taken are indicated in the upper left corner of each figure (see Fig. 1). Statistical parameters are indicated in Fig. 4.

Fig. 5 in New findings reveal that the Middle Triassic ichthyosaur Mixosaurus cornalianus is the oldest amniote with a dorsal fin

Fig. 5. SEM images of microsampled soft tissues of mixosaurid ichthyosaur Mixosaurus cornalianus Bassani, 1886 (BES SC 1000), Sasso Caldo quarry, Besano, Italy, upper Anisian.. A. Collagen fibres packed in parallel bundles from the leading edge of the dorsal fin. B. Close-up of a single fibre showing very fine striations, interpreted as collagen fibrils. C. A pair of collagen fibres from the base of the caudal fin, still covered by a patch of multi-layered scaleless skin. D. Close-up of the skin layers seen in C. Asterisks indicate locations of the back-scattered electron element microanalysis performed on dorsal fin fibres (E), caudal fin fibres (F), and caudal fin skin (G). The peaks illustrate the relative abundance of each element, with higher intensities indicating greater abundance. Note the enrichment of calcium and phosphorous in the fossilised soft tissue, with some variation in secondary minerals.

Fig. 1 in New findings reveal that the Middle Triassic ichthyosaur Mixosaurus cornalianus is the oldest amniote with a dorsal fin

Fig. 1. General location and geological map of the Monte San Giorgio area. The asterisk indicates the position of the Sasso Caldo site.

Fig. 8 in New findings reveal that the Middle Triassic ichthyosaur Mixosaurus cornalianus is the oldest amniote with a dorsal fin

Fig. 8. Reconstruction of the skeleton and body outline of mixosaurid ichthyosaurMixosaurus cornalianus with the dorsal fin and the dorsal lobe of the caudal fin, as preserved in BES SC 1000 (A) compared to the body outline of the small tail shark Carcharinus porosus (B), which average length is similar to that of Mixosaurus.

Fig. 4. Mixosaurid ichthyosaur Mixosaurus cornalianus Bassani, 1886 in New findings reveal that the Middle Triassic ichthyosaur Mixosaurus cornalianus is the oldest amniote with a dorsal fin

Fig. 4. Mixosaurid ichthyosaur Mixosaurus cornalianus Bassani, 1886 (BES SC 1000), Sasso Caldo quarry, Besano, Italy, upper Anisian. A. General view of the specimen showing the position of the dorsal fin (black arrow) and of the dorsal lobe of the caudal fin (white arrow). B. Explanatory drawing showing the position of the dorsal fin (dark grey), skin remains (grey), and neural spines (light grey). C. Close up of the shaft of the dorsal fin showing parallel fibres. D. Dorsal lobe of the caudal fin. E, F. Close ups of the areas of the dorsal lobe of the caudal fin where other fibres and skin remains are exposed.

Fig. 3. Mixosaurid ichthyosaur Mixosaurus cornalianus Bassani, 1886 in New findings reveal that the Middle Triassic ichthyosaur Mixosaurus cornalianus is the oldest amniote with a dorsal fin

Fig. 3. Mixosaurid ichthyosaur Mixosaurus cornalianus Bassani, 1886, Sasso Caldo quarry, Besano, Italy, upper Anisian. A. BES SC 1000. B. BES SC 1001.

Fig. 7 in New findings reveal that the Middle Triassic ichthyosaur Mixosaurus cornalianus is the oldest amniote with a dorsal fin

Fig. 7. Stomach contents of mixosaurid ichthyosaur Mixosaurus cornalianus Bassani, 1886 (A, B, BES SC 1000; C, D, BES SC 1001), Sasso Caldo quarry, Besano, Italy, upper Anisian. A. Cephalopod hooklets (arrowed). B. Enigmatic (neoselachian?) vertebral centrum (arrowed) embedded in the dark material of the decayed stomach. C. Isolated actinistian scale (arrowed). D. Semi-articulated actinopterygian scales (arrowed) embedded in the stomach area. Scale bars 1 mm.

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Figure 2 in Cretaceous marine amniotes of Australia: perspectives on a decade of new research

Figure 2. Diagrammatic map of Cretaceous rock outcrops on the Australian continent with state borders and specific locality references for fossil occurrences discussed in the text (developed from Kear and Hamilton-Bruce, 2011).

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Figure 1 in Cretaceous marine amniotes of Australia: perspectives on a decade of new research

Figure 1. Stratigraphical distribution of Australian Cretaceous marine amniote taxa updated from Kear (2003). Australian standard microplankton (dinoflagellate) zonation is modified from Partridge (2006) to accommodate the emended geological timescale of Gradstein et al. (2012). Taxon ranges indicate named species (black bars) or indeterminate occurrences assigned to higher-level taxa (open bars).

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Figure 3 in Cretaceous marine amniotes of Australia: perspectives on a decade of new research

Figure 3. Marine amniote fossils from Cretaceous strata in Australia. A, elasmosaurid premaxillary palate (SAM P40510) exposing the vomerine contact and intracranial sinus. B, spectacular mounted skeleton (QM F18041) of the new polycotylid popularly dubbed the 'Richmond pliosaur'. C, partially disarticulated 'juvenile' postcranium referred to Umoonasaurus demoscyllus. Both scapulae (outlined) and an in situ gastrolith mass are indicated. D, 'Umoonasaurus-like' propodial from the late Aptian Darwin Formation, Northern Territory. E, CT rendering of an exceptionally preserved 'juvenile' Platypterygius australis cranium and mandible (AM F98273). Image compilation: Ben Hill (Adelaide). F, articulated humerus and distal forelimb elements (AM F107444) of a 'juvenile' Platypterygius australis. G, ophthalmosaurian phalanx (WAM 99.1.4) from the late Cenomanian Geale Siltstone, Western Australia. Image: Mikael Siversson (Western Australian Museum). H, mosasaurid ulna (UWA 37092) with antebrachial foramen and intermedium contact indicated. I, cranium of Bouliachelys suteri (SAM P41106) in lateral view. J, articulated cranium and carapace of Bouliachelys suteri (SAM P40525) in dorsal view. Scale bars represent 20 mm in A, G, H; 500 mm in B; 100 mm in C, J; and 50 mm in D–F, I. Abbreviations: abf – antebrachial foramen; dfi – distal facet for the intermedium; ics – intracranial sinus; gst – gastrolith mass; hpx – hooked premaxillae; lea – lateral exposure of angular; pmj – premaxillary, maxillary, and jugal contacts; rbe – reduced basioccipital extracondylar area; rze – position of radial zeugopodial element; scp – scapulae.

Fig. 8 in Toward the origin of amniotes: Diadectomorph and synapsid footprints from the early Late Carboniferous of Germany

Fig. 8. Stratocladogram of tetrapod phylogeny. Although extending the known body fossil record, the stratigraphic position of the diadectomorph and synapsid footprints from the Bochum Formation of western Germany fits well the phylogenetic pattern. Black bars indicate the known record of skeletal remains (Reisz 1986; Kissel and Reisz 2004a, b). Cladogram topology and minimum times of divergence are based on Kissel and Reisz (2004a, b), Müller and Reisz (2004), and Reisz (2007). The chronostratigraphic scale is adopted from Menning (2005).

Fig. 7 in Toward the origin of amniotes: Diadectomorph and synapsid footprints from the early Late Carboniferous of Germany

Fig. 7. Comparison of trackway pattern and selected parameters of Dimetropus sp. from the Late Carboniferous Bochum Formation, Ruhr area, Germany, DBM 060003260001 to DBM 060003260005 (A) and Dimetropus leisnerianus from the Early Permian Tambach Formation, Thuringian Forest, Germany, MNG 1762 (B), MNG 1828 (C), MNG 13490 (D). E, F. Derived trackway and imprint parameters graphically expressing the mean, minimum, and maximum values. G, H. Relative lengths of the manus and pes imprint digit lengths expressed as a percentage of the length of digit IV. Data source for E–H, see Appendix 4.

Fig. 3 in Toward the origin of amniotes: Diadectomorph and synapsid footprints from the early Late Carboniferous of Germany

Fig. 3. Undertrack preservation in Ichniotherium tetrapod footprints. A. Ichniotherium praesidentis (Schmidt, 1956) from the Late Carboniferous Bochum Formation, Ruhr area, Germany; DBM 060003309003. B–D. Ichniotherium cottae (Pohlig, 1885) from Early Permian strata of the Thuringian Forest area, Germany; MNG 2049 (B), MNG 1871 (C), and MNG 2016 (D). Semicircularly arranged spherical imprints of the digit tips of the digits I–III or I–IV, which are typical in appearance to the undertrack preservation of Ichniotherium. Scale bars 100 mm.

Fig. 6 in Toward the origin of amniotes: Diadectomorph and synapsid footprints from the early Late Carboniferous of Germany

Fig. 6. Comparison between tracks of Dimetropus sp. from the Late Carboniferous Bochum Formation, Ruhr area, Germany, DBM 060003260001 (A) and DBM 060003260003 (B) and Dimetropus leisnerianus (Geinitz, 1863) from the Early Permian Tambach Formation, Thuringian Forest, Germany, MNG 1762 (C). Scale bars 100 mm.

Fig. 4 in Toward the origin of amniotes: Diadectomorph and synapsid footprints from the early Late Carboniferous of Germany

Fig. 4. Graphic comparisons of the trackway pattern and selected parameters of three Ichniotherium ichnospecies. A. Ichniotherium praesidentis from the Bochum Formation, Late Carboniferous, Germany; DBM 060003309001 to DBM 060003309004, part). B–D. Ichniotherium sphaerodactylum from the Tambach Formation, Early Permian, Germany; MB ICV.2 (B), MNG 1351 (C), and GZG 1270 (D). E–G. Ichniotherium cottae from the Tambach Formation, Early Permian, Germany; MNG 10179 (E), UGBL F1 (F), and MNG 1352 (G). H, I. Derived trackway and imprint parameters graphically expressing the mean, minimum, and maximum values. J, K. Relative lengths of the manus and pes imprint digit lengths expressed as a percentage of the length of digit IV. Data source for H–K, see Appendix 2.

Fig. 2 in Toward the origin of amniotes: Diadectomorph and synapsid footprints from the early Late Carboniferous of Germany

Fig. 2. Tetrapod footprints of Ichniotherium praesidentis (Schmidt, 1956) from the Late Carboniferous Bochum Formation, Ruhr area, Germany, represented by the longest and best preserved trackway of the holotype. Photograph and drawing are based on the four−part resin replica (DBM 060003309001 to DBM 060003309004). Note: the first two imprints are erroneously replicated twice and therefore not shown in the outline drawing. Dotted zigzag line links the pes imprints, and dotted track outlines indicate the position of imprints, which are reasoned from the step cycle but not preserved on the cast.

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Figure 1 in Embryo retention, character optimization, and the origin of the extra-embryonic membranes of the amniotic egg

Figure 1. Sarcopterygian phylogeny showing an optimization of embryo retention (character 1), as previously advocated by Laurin and Girondot (1999). The only modification is that all terminal taxa are in the present tree, instead of collapsing Monotremata and Theria into Mammalia, to better match the character distribution shown in Table I, and that Actinistia is coded as unknown (as shown by the absence of a data box below that taxon).