H. D. Blainville, Lettre de Monsieur de Blainville, p.495, 1853.

, Lettres sur les Crocodiles vivants et fossiles. Mémoires Société Linnéenne de Normandie, p.496

F. Caen,

H. G. Bronn, Über die fossilen Gaviale der Lias Formation und der Oolithe, Archiv für, p.498, 1841.

. Naturgeschichte, , vol.8, pp.77-82

S. L. Brusatte, A. Muir, M. T. Young, S. Walsh, L. Steel et al., The braincase 500 and neurosensory anatomy of an Early Jurassic marine crocodylomorph: Implications for 501 crocodylian sinus evolution and sensory transitions, The Anatomical Record, vol.299, pp.1511-1530, 2016.

M. C. Buchy, E. Frey, and S. W. Salisbury, The internal cranial anatomy of the Plesiosauria 503 (Reptilia, Sauropterygia): evidence for a functional secondary palate, Lethaia, vol.39, pp.289-303, 2006.

A. B. Butler and W. Hodos, Comparative Vertebrate Neuroanatomy: Evolution and 505, 2005.

, Adaptation, vol.744, p.pp

M. W. Caldwell, Modified perichondral ossification and the evolution of paddle-like limbs in 507 ichthyosaurs and plesiosaurs, Journal of Vertebrate Paleontology, vol.17, pp.534-547, 1997.

C. L. Camp, California mosasaurs, p.509, 1942.

U. S. , , vol.67, p.pp

K. Carpenter, Comparative cranial anatomy of two North American Cretaceous plesiosaurs, 1997.

, Ancient Marine Reptiles, pp.191-216

J. Clarke and S. Etches, Predation among Jurassic reptiles, Proceedings of the Dorset 514 Natural History and Archaeological Society, vol.113, pp.202-205, 1992.

M. L. Concha and S. W. Wilson, Asymmetry in the epithalamus of vertebrates, The Journal 516 of Anatomy, vol.199, pp.63-84, 2001.

A. Connolly, Exploring the Relationship between Paleobiogeography, p.518, 2016.

, Size Variation of the Parietal Eye in Mosasaurs, vol.43, p.pp

J. R. Corfield, K. Price, A. N. Iwaniuk, C. Gutierrez-ibanez, T. Birkhead et al., , 2015.

, Diversity in olfactory bulb size in birds reflects allometry, ecology and phylogeny, vol.522

A. R. Cruickshank, P. G. Small, and M. A. Taylor, Dorsal nostrils and hydrodynamically 524 driven underwater olfaction in plesiosaurs, Nature, vol.352, pp.62-64, 1991.

R. S. Cuthbertson, H. C. Maddin, R. B. Holmes, and J. S. Aanderson, The braincase and 526 endosseous labyrinth of Plioplatecarpus peckensis (Mosasauridae, Plioplatecarpinae), with 527 functional implications for locomotor behavior, The Anatomical Record, vol.298, pp.1597-1611, 2015.

T. Edinger, Über Nothosaurus. II. Zur Gaumenfrage. Senckenbergiana, vol.3, pp.193-205, 1921.

T. Edinger, Über einige fossile Gehirne, Paläontologische Zeitschrift, vol.9, pp.379-402, 1928.

E. M. Ettachfini and B. Andreu, Le Cénomanien et le Turonien de la plate, p.531, 2004.

, Préafricaine du Maroc. Cretaceous Research, vol.25, pp.277-302

M. Evans, A new reconstruction of the skull of the Callovian elasmosaurid plesiosaur 533, 1999.

, Muraenosaurus leedsii Seeley. Mercian Geologist, vol.14, pp.191-198

J. Falcon, Cellular circadian clocks in the pineal, Progress in neurobiology, vol.58, pp.121-162, 1999.

D. Foffa, J. Sasson, A. R. Cuff, M. N. Mavrogordato, and M. J. Benton, Complex rostral 536 neurovascular system in a giant pliosaur, Naturwissenschaften, vol.101, pp.453-456, 2014.

R. Forrest, A large rhomaleosaurid pliosaur from the Upper Lias of Rutland, Mercian 538 Geologist, vol.15, pp.37-40, 2000.

S. Garman, Bulletin of the Museum of Comparative 540, Zoology, vol.6, pp.123-126, 1880.

Z. L. Gasparini and D. Dellapé, Un nuevo cocodrilo marino (Thalattosuchia, p.542, 1976.

, Metriorhynchidae) de la Formacion Vaca Muerta (Jurasico, Titoniano) de la provincia de 543

, Neuquen. Actas I Congreso Geologico Chileno, vol.1, pp.1-21

E. B. Giffin, Pacycephalosaur Paleoneurology (Archosauria: Ornithischia), Journal, p.545, 1989.

, Vertebrate Paleontology, vol.9, pp.67-77

G. C. Gundy, C. L. Ralph, and G. Z. Wurst, Parietal eyes in lizards: zoogeographical 547 correlates, vol.190, pp.671-673, 1975.

Y. Herrera, Metriorhynchidae (Crocodylomorpha: Thalattosuchia) from Upper Jurassic-549, 2015.

, Lower Cretaceous of Neuquén Basin (Argentina), with comments on the natural casts of the 550 brain, Publicación Electrónica de la Asociación Paleontológica Argentina, vol.15, pp.159-171

Y. Herrera, M. S. Fernandez, and Z. Gasparini, The snout of Cricosaurus araucanensis: a 552 case study in novel anatomy of the nasal region of metriorhynchids, Lethaia, vol.46, pp.331-340, 2013.

Y. Herrera, J. M. Leardi, and M. S. Fernández, Braincase and endocranial anatomy of two 554 thalattosuchian crocodylomorphs and their relevance in understanding their adaptations to the 555 marine environment, PeerJ, vol.6, 2018.

W. L. Holloway, K. M. Claesson, and F. R. O'keefe, A virtual phytosaur endocast and its 557 implications for sensory system evolution in archosaurs, Journal of Vertebrate Paleontology, vol.558, pp.848-857, 2013.

J. A. Hopson, Paleoneurology, p.560, 1979.

, Biology of the Reptilia, vol.9

G. R. Hurlburt, R. C. Ridgely, and L. M. Witmer, Relative size of brain and cerebrum in 562 tyrannosaurid dinosaurs: an analysis using brainendocast quantitative relationships in extant 563 alligators, p.564, 2013.

, Tyrannosaurid paleobiology

V. H. Hutchison and R. J. Kosh, Thermoregulatory function of the parietal eye in the lizard 566, 1974.

, Anolis carolinensis. Oecologia, vol.16, pp.173-177

H. J. Jerison, Evolution of the brain and intelligence, vol.482, p.pp, 1973.

D. Jirak and J. Janacek, Volume of the crocodilian brain and endocast during ontogeny, 2017.

, PLoS ONE, vol.12

W. J. Kennedy, A. S. Gale, D. J. Ward, and C. J. Underwood, Early Turonian ammonites 571 from Goulmima, southern Morocco, Sciences Naturelles de 572 Belgique, vol.78, pp.149-177, 2008.

R. Kim, D. Evans, and D. , Relationships among brain, endocranial cavity, and body sizes in 574 reptiles, Society of Vertebrate Paleontology 575 74th Annual Meeting, 2014.

T. Kishida, J. G. Thewissen, T. Hayakawa, H. Imai, and K. Agata, Aquatic adaptation 577 and the evolution of smell and taste in whales, Zoological Letters, vol.1, pp.1-9, 2015.

E. Koken, Beitrage zur Kenntnis der Gattung Nothosaurus. Zeitschrift der deutschen 579 geologischen Gesellschaft, vol.45, pp.337-377, 1893.

T. Konishi, M. W. Caldwell, T. Nishimura, K. Sakurai, and K. Tanoue, A new halisaurine 581 mosasaur (Squamata: Halisaurinae) from Japan: the first record in the western Pacific realm 582 and the first documented insights into binocular vision in mosasaurs, Journal of Systematic 583 Palaeontology, vol.14, pp.809-839, 2016.

A. Labra, K. L. Voje, H. Seligmann, and T. F. Hansen, Evolution of the third eye: a 585 phylogenetic comparative study of parietal-eye size as an ecophysiological adaptation in 586 Liolaemus lizards, Biological journal of the Linnean Society, vol.101, pp.870-883, 2010.

J. Leidy, Cretaceous reptiles of the United States, p.588, 1865.

U. S. , , vol.135, p.pp

C. Linnaeus, Systema Naturae per regna tria naturae, secundum classes, ordines, genera, 590 species, cum characteribus, differentiis, synonymis, locis. Tomus II. Editio duodecima, 591 reformata, Laurentius Salvius, vol.824, p.pp, 1758.

C. Linnaeus, Systema naturae per regna tria naturae, secundum classes, ordines, genera, 593 species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio duodecima, 594 reformata, Laurentii Salvii, vol.532, p.pp, 1766.

T. E. Macrini, T. Rowe, and M. Archer, Description of a cranial endocast from a fossil 596 platypus, Obdurodon dicksoni (Monotremata, Ornithorhynchidae), and the relevance of 597 endocranial characters to monotreme monophyly, Journal of Morphology, vol.267, pp.1000-1015, 2006.

T. E. Macrini, T. Rowe, and J. L. Vandeberg, Cranial endocasts from a growth series of 599, 2007.

, Monodelphis domestica (Didelphidae, Marsupialia): A study of individual and ontogenetic 600 variation, Journal of Morphology, vol.268, pp.844-865

R. D. Marek, B. C. Moon, M. Williams, and J. Benton, , p.602, 2015.

, Lower Jurassic ichthyosaur based on digital reconstructions, Palaeontology, vol.58, pp.723-742

J. A. Massare, Tooth morphology and prey preference of Mesozoic marine reptiles, Journal 604 of Vertebrate Paleontology, vol.7, pp.121-137, 1987.

J. A. Massare, Swimming capabilities of Mesozoic marine reptiles: implications for method 606 of predation, Paleobiology, vol.14, pp.187-205, 1988.

C. Mcgowan, The cranial morphology of the Lower Liassic latipinnate ichthyosaurs of 608, 1973.

. England, Bulletin of the British Museum, vol.24, pp.1-109

C. R. Mchenry, A. G. Cook, and S. Wroe, Bottom-feeding plesiosaurs, Science, vol.310, p.75, 2005.

G. Münster, Vorliufige Nachricht fiber einige neue Reptilien im Muschelkalke von Baiern, 1834.

, Neues Jahrbuch ffir die Mineralogie, vol.1834, p.521

J. M. Neenan and T. M. Scheyer, The braincase and inner ear of Placodus gigas 614 (Sauropterygia, Placodontia), a new reconstruction based on micro-computed tomographic 615 data, Journal of Vertebrate Paleontology, vol.32, pp.1350-1357, 2012.

J. M. Neenan, T. Reich, S. W. Evers, P. S. Druckenmiller, D. F. Voeten et al.,

M. Barrett, S. E. Pierce, and R. B. Benson, Evolution of the Sauropterygian Labyrinth 618 with Increasingly Pelagic Lifestyles, Current Biology, vol.27, pp.3852-3858, 2017.

R. Nieuwenhuys, H. J. Ten-donkelaar, and C. Nicholson, The Central Nervous System of 620 Vertebrates, 1998.

R. F. O'keefe, A cladistic analysis and taxonomic revision of the Plesiosauria (Reptilia: 622 Sauropterygia), Acta Zoologica Fennica, vol.213, pp.1-63, 2001.

R. F. O'keefe, The evolution of plesiosaur and pliosaur morphotypes in the Plesiosauria 624 (Reptilia: Sauropterygia), Paleobiology, vol.28, pp.101-112, 2002.

R. F. O'keefe and L. M. Chiappe, Viviparity and K-selected life history in a Mesozoic 626 marine plesiosaur (Reptilia, Sauropterygia), Science, vol.333, pp.870-873, 2011.

R. F. O'keefe, R. A. Otero, S. Soto-acuña, J. P. O'gorman, S. J. Godfrey et al., , 2017.

, Cranial anatomy of Morturneria seymourensis from Antarctica, and the evolution of filter 629 feeding in plesiosaurs of the Austral Late Cretaceous, Journal of Vertebrate Paleontology, vol.630, p.37

A. Palci, M. N. Hutchinson, M. W. Caldwell, and M. S. Lee, The morphology of the inner 632 ear of squamate reptiles and its bearing on the origin of snakes, Royal Society open science, vol.633, 2017.

A. Palci, M. N. Hutchinson, M. W. Caldwell, and J. Scanlon, Palaeoecological inferences for 635 the fossil Australian snakes Yurlunggur and Wonambi (Serpentes, Madtsoiidae), Royal 636 Society Open Science, vol.5, 2018.

A. P. Paulina-carabajal, J. Sterli, J. Muller, and A. Hilger, Neuroanatomy of the marine 638 Jurassic turtle Plesiochelys etalloni (Testudinata, Plesiochelyidae), PLoS ONE, vol.639, 2013.

F. J. Pictet and A. Humbert, 1857. Description d'une émyde nouvelle (Emys Etalloni) du terrain 641 jurassique supérieur des environs de St-Claude, Matériaux 642 pour la paléontologie suisse. Première série, pp.256-273

S. E. Pierce, M. Williams, M. , and R. B. Benson, Virtual reconstruction of the endocranial 644 anatomy of the early Jurassic marine crocodylomorph Pelagosaurus typus (Thalattosuchia), 2017.

, PeerJ, vol.5, p.3225

W. B. Quay, The parietal eye-pineal complex, Biology of the Reptilia, vol.9, pp.245-406, 1979.

C. L. Ralph, The pineal gland and geographical distribution of animals, International Journal 649 of Biometeorology, vol.19, pp.289-303, 1975.

C. L. Ralph, B. T. Firth, and J. S. Turner, The role of the pineal body in ectotherm 651 thermoregulation, American Zoologist, vol.19, pp.273-293, 1979.

B. M. Rothschild and G. W. Storrs, Decompression syndrome in plesiosaurs (Sauropterygia: 653 Reptilia), Journal of Vertebrate Paleontology, vol.23, pp.324-328, 2003.

S. Sachs and B. P. Kear, Postcranium of the paradigm elasmosaurid plesiosaurian 655 Libonectes morgani (Welles, 1949), Geological Magazine, vol.152, pp.694-710, 2015.

S. Sachs, J. Lindgren, and M. Siversson, , p.657, 2015.

. Cretaceous-of-sweden, Geological Society, vol.434, pp.293-301

S. Sachs, J. J. Hornung, and B. P. Kear, Reappraisal of Europe's most complete Early 659, 2016.

, Cretaceous plesiosaurian: Brancasaurus brancai Wegner, 1914 from the "Wealden facies, p.660

. Germany, PeerJ, vol.4

T. Sato, Terminonatator ponteixensis, a new elasmosaur (Reptilia; Sauropterygia) from the 662, 2003.

, Upper Cretaceous of Saskatchewan, Journal of Vertebrate Paleontology, vol.23, pp.89-103

T. Sato and K. Tanabe, Cretaceous plesiosaurs ate ammonites, Nature, vol.394, pp.629-630, 1998.

T. Sato, X. C. Wu, A. Tirabasso, A. , and P. Bloskie, Braincase of a polycotylid plesiosaur 665 (Reptilia: Sauropterygia) from the Upper Cretaceous of Manitoba, Canada. Journal, p.666, 2011.

, Vertebrate Paleontology, vol.31, pp.313-329

H. G. Seeley, Note on the cranial characters of a large teleosaur from the Whitby Lias 668 preserved in the Woodwardian museum of the University of Cambridge, indicating a new 669 species, Teleosaurus eucephalus, Quarterly Journal of the Geological Society, vol.36, pp.627-634, 1880.

A. G. Sennikov and M. S. Arkhangelsky, On a typical Jurassic sauropterygian from the 671, 2010.

, Arctic Russia). Paleontological Journal, vol.672, pp.567-572

E. W. Shuler, A new elasmosaur from the Eagle Ford Shale of Texas, Fondren Science Series, vol.674, pp.1-33, 1950.

K. T. Smith, . S. B-a, G. Bhullar, J. Köhler, and . Habersetzer, The only known jawed 676 vertebrate with four eyes and the Bauplan of the pineal complex, Current Biology, vol.28, pp.1101-677, 2018.

D. Starck, Cranio-cerebral relations in Recent reptiles, p.679, 1979.

, Biology of the Reptilia, vol.9, p.680

. London,

G. W. Storrs, A juvenile specimen of ?, Plesiosaurus sp. from the Lias, p.682, 1995.

. Pliensbachian)-near-charmouth and E. Dorset, Proceedings of the Dorset Natural History 683 and Archaeological Society, vol.116, pp.71-76

L. B. Tarlo, Pliosaurus brachyspondylus (Owen) from the Kimeridge Clay, Palaeontology, vol.685, pp.283-291, 1959.

W. T. Thach and A. J. Bastian, Role of the cerebellum in the control and adaptation of gait 687 in health and disease, Progress in brain research, vol.143, pp.353-366, 2004.

G. Tosini, The pineal complex of reptiles: physiological and behavioral roles, Ethology 689 Ecology & Evolution, vol.9, pp.313-333, 1997.

D. Vandelli, Epistola de holothurio, et testudine coriacea ad celeberrimum Carolum 691, 1761.

, Linnaeum equitem naturae curiosum Dioscoridem II. Conzatti, vol.12, p.pp

P. Vignaud, Une Nouvelle espèce de Steneosaurus (Thalattosuchia, Teleosauridae) dans le 693, 1998.

P. Callovien-du, France) et la systématique des Steneosaurus longirostres du Jurassique 694 moyen d'Europe occidentale, Palaeovertebrata, vol.27, pp.19-44

P. Vignaud and Z. B. Gasparini, New Dakosaurus (Crocodylomorpha, Thalattosuchia) from 696 the Upper Jurassic of Argentina, Comptes Rendus de l'Académie des Sciences, vol.322, p.245, 1996.

P. Vincent, R. Allemand, P. D. Taylor, G. Suan, and E. E. Maxwell, New insights on the 699 systematics, palaeoecology and palaeobiology of a plesiosaurian with soft tissue preservation 700 from the Toarcian of Holzmaden, The Science of Nature, vol.104, p.51, 2017.

P. Vincent, N. Bardet, X. Suberbiola, B. Bouya, M. Amaghzaz et al., , 2011.

, Reptilia: Sauropterygia) from the Maastrichtian 703 Phosphates of Morocco and the palaeobiogeography of latest Cretaceous plesiosaurs, Zarafasaura oceanis, a new elasmosaurid

, Gondwana Research, vol.19, pp.1062-1073

D. F. Voeten, T. Reich, R. Araujo, and T. M. Scheyer, Synchrotron microtomography 706 of a Nothosaurus marchicus skull informs on nothosaurian physiology and neurosensory 707 adaptations in early Sauropterygia, PLoS ONE, vol.13, 2018.

M. Wade, A review of the Australian Cretaceous longipinnate ichthyosaur Platypterygius 709 (Ichthyosauria: Ichthyopterygia), Memoirs of the Queensland Museum, vol.28, pp.115-137, 1990.

S. P. Welles, A review of the North American Cretaceous elasmosaurs, p.711, 1952.

. California, Publications in Geological Sciences, vol.29, pp.47-144

S. Wenz, Contribution à l'étude du genre Metriorhynchus. Crâne et moulage endocrânien de 713, 1968.

, Metriorhynchus superciliosus, Annales de Paléontologie (Vertébrés), vol.54, pp.149-183

F. Westphal, Zur Systematik der deutschen und englischen Lias Krokodilier. Neues Jahrbuch, 715 für Geologie und Paläontologie, Abhandlungen, vol.113, pp.207-218, 1961.

D. S. Wharton, An enlarged endocranial venous system in, Steneosaurus pictaviensis 717 (Crocodylia: Thalattosuchia) from the Upper Jurassic of Les Lourdines, 2000.

. Rendus, Académie des Sciences, Series IIA, Earth and Planetary Science, vol.331, pp.221-226

T. Wintrich, S. Hayashi, A. Houssaye, Y. Nakajima, and P. M. Sander, A Triassic 720 plesiosaurian skeleton and bone histology inform on evolution of a unique body plan, Science, vol.721, 2017.

L. M. Witmer and R. C. Ridgely, New insights into the brain, braincase, and ear region of 723 tyrannosaurs (Dinosauria, Theropoda), with implications for sensory organization and 724 behavior, The Anatomical Record, vol.292, pp.1266-1296, 2009.

L. M. Witmer, R. C. Ridgely, D. L. Dufeau, and M. C. Semones, Using CT to peer into the 726 past: 3D visualization of the brain and ear regions of birds, crocodiles, and nonavian 727 dinosaurs, Anatomical imaging: towards a new 728 morphology, pp.67-88, 2008.

J. Wyneken, The external morphology, musculoskeletal system, and neuro-anatomy of sea 730 turtles, The biology of sea 731 turtles, vol.2, pp.39-77, 2003.

J. Wyneken, Reptilian neurology: anatomy and function, America: Exotic Animal Practice, vol.733, pp.837-853, 2007.

, FIGURE 1. Photographs of the Libonectes morgani specimens D1-8213 (A, B) and SMNS 739 81783 (C, D); and of the undetermined polycotylid MNHN F-GOU14 (E, F), all from the 740 lower Turonian of Goulmima (Morocco) in dorsal (up)

, FIGURE 2. Individual slice data (A-I) through the cranium of Libonectes morgani, pp.1-8213

, Positions of the transverse sections are shown in dorsal cranial surface model. Images in A-I 749 not to scale. Abbreviations: bo, basioccipital; ect, ectopterygoid; ep, epipterygoid; eo, p.750

, A) and SMNS 81783 (B); and the undetermined Polycotylidae MNHN F-GOU14 (C) in

, dorsal (top) and left lateral (bottom) views. Abbreviations: cb, cerebellum; cer, cerebral 760 hemispheres; ic, internal carotid; mo, medulla oblongata; ob, olfactory bulbs; ol

V. ,

. Vii and . Ix, X-XI, vagus and accessory nerves; XII, 763 hypoglossal nerves. Scale bars equal 20 mm. The dotted-lines indicate the missing parts, the 764 specimen A is used as a reference for other two specimens

, Left endosseous 781 labyrinth of D1-8213 in lateral (top) and dorsal (bottom) views. Abbreviations: aa, anterior 782 ampulla; asc, anterior semicircular canal; cc, common crus; ic

, lateral semicircular canal; pa, posterior ampulla; psc, posterior semicircular canal

. Vi, VII, facial nerve; IX, glossopharyngeal nerve; X-XI, vagus 785 and accessory nerves; XII, hypoglossal nerves. Scale bars equal 20 mm