Ichthyosauria

Various fossils pertaining to the holotype of the Triassic ichthyosaur Toretocnemus (originally Leptocheirus, also Merriamia) zitteli. This image is derived from plate 23 in Merriam (1903), done by an uncredited artist. The arrangement of the individual figures has been modified from the original (most notably, figures 3 and 4 were swapped to minimize confusion). Original description: Leptocheirus zitteli n. gen. and sp. Figures reproduced natural size from the type specimen. Fig. 1.— Right side of skull. Fig. 2. — Cross-section of posterior portion of the lower jaw, taken above the point marked A on the lateral view of the skull. Fig. 3. — Cross-section of the upper and lower jaws, taken at the break immediately behind the point marked Sp on the lateral view of the skull. Fig. 4. — Lateral view of an anterior caudal centrum. Legend (modified from original): Ar - articular A - angular D - dentary J - jugal L - lacrimal Mx - maxilla Po - postorbital Sa - surangular Se - sclerotic ring Sp - spenial T - cross-section of tooth X - doubtful element

The shoulder girdle of the holotype of the Triassic ichthyosaur Toretocnemus (originally Leptocheirus, also Merriamia) zitteli. This image is derived from plate 21 in Merriam (1903), done by an uncredited artist. The arrangement of the individual figures has been slightly modified from the original. Original description: Leptocheirus zitteli n. gen. and sp. Figures reproduced natural size from the type specimen. Fig. 1.—Clavicles (cl) and probable interelavicle (Ic and Ic')- The interclavicle has been separated into two fragments by a crack in the matrix. Fig. 2.—Inner side of the coracoids and the left scapula.

Forelimb and partial hindlimb of the holotype of the Triassic ichthyosaur Toretocnemus (originally Leptocheirus, also Merriamia) zitteli. This image is derived from plate 22 in Merriam (1903), done by an uncredited artist. Original description: Leptocheirus zitteli n. gen. and sp. Figures reproduced natural size from the type specimen. Fig. 1. — Superior side of left anterior limb. r, radius. Fig. 2. — Posterior limb. t, tibia.

Various fossils pertaining to the holotype of the Triassic ichthyosaur Toretocnemus californicus. This image is derived from plate 24 in Merriam (1903), done by an uncredited artist. The arrangement of the individual figures has been modified from the original. Original description: Toretocnemus californicus n. gen. and sp. Figures reproduced natural size from the type specimen. Fig. 1. — Inferior side of right posterior limb. t, tibia. Fig. 2. — Right anterior limb. r, radius. Fig. 3.— Pelvic arch. Fig. 4. — Middle dorsal vertebrae and a rib from the same region.

Illustration of some anterior caudal vertebrae of the Californian ichthyosaur Torteocnemus californicus (specimen UCMP 8100), from Merriam's 1908 monograph on American Triassic ichthyosaurs. This illustration appeared as figure 4 of plate 14; it has been modified to remove the stamp placed on top of it. While Merriam credits two illustrators as having produced artwork for this publication, it is not clear which of them created this image.

Life restoration of the Triassic ichthyosaur Qianichthyosaurus xingyiensis. References Motani, Ryosuke; Jiang, Da-yong; Tintori, Andrea; Ji, Cheng; Huang, Jian-dong (2017). "Pre- versus post-mass extinction divergence of Mesozoic marine reptiles dictated by time-scale dependence of evolutionary rates". Proceedings of the Royal Society B 284 (1854): 20170241. DOI:10.1098/rspb.2017.0241.

Comparison between the tails of for different Ichthyosauria specimens, captions present and in German, from Abel, O. (1919). Die Stämme der Wirbeltiere.

Figure description from paper: "Figure 23: Early and Middle Triassic ichthyopterygian heads possessing longirostry. Simplified outlines of four different Early and Middle Triassic ichthyopterygian heads possessing a long and slender rostrum. Specimens are at the same scale. (A) Utatsusaurus hataii (UHR 30691, Motani, Minoura & Ando, 1998); (B) Grippia longirostris (PMU R445, Motani, 2000); (C) Mixosaurus cornalianus (BES SC 1000, Renesto et al., 2020); (D) Besanosaurus leptorhynchus (PIMUZ T 4847, this paper); (E) Cymbospondylus buchseri (PIMUZ T 4351, Sander, 1989). Scale bar represents 10 cm." References: Bindellini, G.; Wolniewicz, A.S.; Miedema, F.; Scheyer, T.M.; Dal Sasso, C. (2021). "Cranial anatomy of Besanosaurus leptorhynchus Dal Sasso & Pinna, 1996 (Reptilia: Ichthyosauria) from the Middle Triassic Besano Formation of Monte San Giorgio, Italy/Switzerland: Taxonomic and palaeobiological implications". PeerJ 9: e11179. DOI:10.7717/peerj.11179.

Besanosaurus leptorhynchus referred specimen PIMUZ T 4376, preserved on the same slab as a specimen of the smaller Mixosaurus. Scale bar represents 50 cm (1.6 ft). Figure 3C of Bindellini et al. (2021). References: Bindellini, G.; Wolniewicz, A.S.; Miedema, F.; Scheyer, T.M.; Dal Sasso, C. (2021). "Cranial anatomy of Besanosaurus leptorhynchus Dal Sasso & Pinna, 1996 (Reptilia: Ichthyosauria) from the Middle Triassic Besano Formation of Monte San Giorgio, Italy/Switzerland: Taxonomic and palaeobiological implications". PeerJ 9: e11179. DOI:10.7717/peerj.11179.

Modified version of figure 23 of Bindellini et al. (2021) showing just the ichthyosaurs from the Besano Formation: Besanosaurus leptorhynchus (A), Mixosaurus cornalianus (B), and Cymbospondylus buchseri (C). The original figure was uploaded unmodified here: File:Early to Middle Triassic Longirostrine Ichthyopterygians.png References: Bindellini, G.; Wolniewicz, A.S.; Miedema, F.; Scheyer, T.M.; Dal Sasso, C. (2021). "Cranial anatomy of Besanosaurus leptorhynchus Dal Sasso & Pinna, 1996 (Reptilia: Ichthyosauria) from the Middle Triassic Besano Formation of Monte San Giorgio, Italy/Switzerland: Taxonomic and palaeobiological implications". PeerJ 9: e11179. DOI:10.7717/peerj.11179.

Identifier: waterreptilesofp1914will Title: Water reptiles of the past and present Year: 1914 (1910s) Authors: Williston, Samuel Wendell, 1851-1918 Subjects: Aquatic reptiles Publisher: Chicago, Ill., The University of Chicago Press Contributing Library: Boston Public Library Digitizing Sponsor: Boston Public Library View Book Page: Book Viewer About This Book: Catalog Entry View All Images: All Images From Book Click here to view book online to see this illustration in context in a browseable online version of this book. Text Appearing Before Image: served and very complete skeletons ofdifferent species of ichthyosaurs from the Jurassic deposits ofWiirtemberg, in which remains of these animals occur in great 112 WATER REPTILES OF THE PAST AND PRESENT profusion. His researches, and those of several authors since then,supplementing and confirming or disproving those of the manyobservers made during the preceding seventy years, have finallydetermined almost perfectly the complete structure of the moretypical ichthyosaurs, enabling us to infer not a little as to theirhabits and distribution in the old Jurassic oceans. Within thepast few years the discoveries of Professor J. C. Merriam of Cali-fornia have likewise added greatly to our knowledge of the earlierichthyosaurs. It may now truthfully be said that of no group ofextinct reptiles do we have a more complete and satisfactory knowl-edge than of the ichthyosaurs. Nevertheless we have yet very much more to learn about theorder Ichthyosauria as a whole—whence they came and how they Text Appearing After Image: Fig. 52.—Ichthyosaurus quadricissus.museum, from Dr. Dreverman. Photograph of specimen in Senckenberg originated; what their nearest kin were among other reptiles; andespecially, more about the connecting links between them andterrestrial reptiles. They have, as an order, so isolated a position,are so widely separated from all other reptiles in structure, that theyhave long been a puzzle to paleontologists. Like the whales andother cetaceans among mammals, we know the ichthyosaurs wellin the plenitude of their power and the fulness of their development,but have yet only an imperfect knowledge of their earlier history,and none whatever of their earliest. However, as will be seenfarther on, the recent discoveries by Merriam have shed much lighton some of the stages of their evolution. So nearly perfectly wereall the later ichthyosaurs adapted to their life in the water that itwas believed by nearly all paleontologists until about a score of years ICHTHYOSAURIA 3 ago that they had desc Note About Images Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original work.

Utatsusaurus hataii, an Early Triassic Ichthyosaur from Japan, pencil drawing

Skull of the Middle Triassic North-American ichthyosaur Cymbospondylus petrinus, preserved in three dimensions. This specimen is cataloged under the number UCMP 9913. More information is available from the source link.

Bituminous claystone, Lower Jurassic, Hesselberg, Middle Franconia. Sedimentary rock of very thin laminated layers (particles less than 0,0002 mm). Rock formation is known for its rich fossil findings, ex. Ichthyosaur.

Life restoration of the German Jurassic ichthyosaur Suevoleviathan disinteger. The dorsal and caudal fins are loosely based on those of Stenopterygius. References Maisch, M.W. (2020). "The best-preserved skeleton of Suevoleviathan integer (Bronn, 1844)(Reptilia: Ichthyosauria) from the lower Jurassic of south-western Germany, with a discussion of the genus". Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen 297 (2): 153–172. Maisch, M.W. (1998). "A new ichthyosaur genus from the Posidonia Shale (Lower Toarcian, Jurassic) of Holzmaden, SW-Germany with comments on the phylogeny of post-Triassic ichthyosaurs". Neues Jahrbuch für Geologie und Paläontologie-Abhandlungen 209 (1): 47–78.