A Long-Snouted Predatory Dinosaur from Africa and the Evolution of Spinosaurids Paul C. Sereno et al. Science 282, 1298 (1998); DOI: 10.1126/science.282.5392.1298 This copy is for your personal, non-commercial use only. If you wish to distribute this article to others, you can order high-quality copies for your colleagues, clients, or customers by clicking here. Permission to republish or repurpose articles or portions of articles can be obtained by following the guidelines here. The following resources related to this article are available online at www.sciencemag.org (this information is current as of September 6, 2013 ): Updated information and services, including high-resolution figures, can be found in the online version of this article at: on September 6, 2013 http://www.sciencemag.org/content/282/5392/1298.full.html This article cites 29 articles, 3 of which can be accessed free: http://www.sciencemag.org/content/282/5392/1298.full.html#ref-list-1 This article has been cited by 90 article(s) on the ISI Web of Science This article has been cited by 15 articles hosted by HighWire Press; see: http://www.sciencemag.org/content/282/5392/1298.full.html#related-urls This article appears in the following subject collections: www.sciencemag.org Geochemistry, Geophysics http://www.sciencemag.org/cgi/collection/geochem_phys Downloaded from Science (print ISSN 0036-8075; online ISSN 1095-9203) is published weekly, except the last week in December, by the American Association for the Advancement of Science, 1200 New York Avenue NW, Washington, DC 20005. Copyright 1998 by the American Association for the Advancement of Science; all rights reserved. The title Science is a registered trademark of AAAS. R EPORTS orly into the body of the maxilla. As in Baryonyx, the quadrate foramen is very large, A Long-Snouted Predatory and the distal condyles are very broad. The new cranial bones indicate that the Dinosaur from Africa and the spinosaurid skull is considerably lower, nar- rower, and longer (Fig. 2D) than previously Evolution of Spinosaurids reconstructed (13, 19). In dorsal view, the snout is extremely narrow (Fig. 2C). In ven- Paul C. Sereno,* Allison L. Beck, Didier B. Dutheil, tral view, the maxillae meet along the mid- Boubacar Gado, Hans C. E. Larsson, Gabrielle H. Lyon, line, displacing the internal nares and palatal Jonathan D. Marcot, Oliver W. M. Rauhut, Rudyard W. Sadleir, complex (pterygoid, palatine, and ectoptery- goid) toward the rear of the skull. Christian A. Sidor, David D. Varricchio, Gregory P. Wilson, In the postcranial skeleton, the cervical Jeffrey A. Wilson series arches upward (18) and has prominent epipophyses for muscle attachments. The Fossils discovered in Lower Cretaceous (Aptian) rocks in the Te´ne´re´ Desert of neural spines increase in height rapidly in the central Niger provide new information about spinosaurids, a peculiar group of middorsal vertebrae, forming a low median piscivorous theropod dinosaurs. The remains, which represent a new genus and sail that is deepest over the sacral vertebrae species, reveal the extreme elongation and transverse compression of the (Fig. 3). This vertebral morphology, incipi- spinosaurid snout. The postcranial bones include blade-shaped vertebral spines ently developed in Baryonyx (13), is distinct that form a low sail over the hips. Phylogenetic analysis suggests that the enlarged thumb claw and robust forelimb evolved during the Jurassic, before the elongated snout and other fish-eating adaptations in the skull. The close phylogenetic relationship between the new African spinosaurid and Baryonyx from Europe provides evidence of dispersal across the Tethys seaway during the Early Cretaceous. In 1912, a series of extremely high-spined remains consist of a single partial skull, Irri- vertebrae and a peculiar lower jaw with sub- tator (9, 10); and the European fossils, Bary- conical crocodilelike teeth were discovered in onyx, include the first relatively complete on September 6, 2013 the Baharıˆya oasis in central Egypt (1). These spinosaurid skeleton (11–13). fossils provided evidence that a large, pis- Fossils were recovered recently from the civorous, sail-backed predator roamed the Elrhaz Formation in Niger (Fig. 1). These northern shores of Africa during the Late Aptian-age rocks consist predominantly of Cretaceous (Cenomanian). This partial skel- fluvial channel deposits and are exposed in eton, Spinosaurus aegyptiacus, was de- low outcrops amid dune fields in the Te´ne´re´ stroyed during World War II, and few re- Desert (6, 14). The fossils found here include mains that are attributable to this taxon have plant, invertebrate, and vertebrate remains; since been recovered in these horizons (2–5). the vertebrate remains consist mainly of dis- www.sciencemag.org Additional bones of Spinosaurus-like articulated bones and teeth in basal channel predators have been discovered in Lower lag deposits. Dinosaurs are represented by at Cretaceous (Aptian or Albian) deposits in least three theropods, two sauropods, and Niger and Brazil and in somewhat older (Bar- three ornithopods (15). remian) rocks in Europe. The Nigerien fossils The newly discovered fossils include a include peculiar arched snout tips and enor- partial skull and skeleton of a new spinosau- mous manual unguals (6–8); the Brazilian rid, Suchomimus tenerensis gen. nov. sp. nov. Downloaded from (16), which can be distinguished from other spinosaurids (17). An articulated snout (Fig. P. C. Sereno, A. L. Beck, H. C. E. Larsson, J. D. Marcot, C. A. Sidor, J. A. Wilson, Department of Organismal 2A and B) reveals its remarkably long, low, Biology and Anatomy, University of Chicago, 1027 and narrow proportions. The elongation of the East 57th Street, Chicago, IL 60637, USA. D. B. snout is the result of the hypertrophy of both the Dutheil, Laboratoire de Pale´ontologie, Muse´um Na- premaxilla and the anterior ramus of the max- tional d’Histoire Naturelle, 8 rue du Buffon, 75005 Paris, France. B. Gado, Institut pour Recherche et illa. The premaxillae, which fuse early in Science Humaine, Republic of Niger. G. H. Lyon, Small growth, each contain alveoli for seven teeth. Schools Workshop, 115 South Sangamon Street, Uni- The subconical crowns are slightly recurved versity of Illinois, Chicago, IL 60607, USA. O. W. M. and have fine marginal serrations and textured Fig. 1. Mid-Cretaceous paleogeography and principal exposures of fossiliferous beds in the Rauhut, Department of Geology, University of Bristol, enamel surfaces (Fig. 2E). The external nares Wills Memorial Building, Queen’s Road, Bristol BS8 region of Gadoufaoua, Niger. (A) Mid-Creta- 1RJ, UK. R. W. Sadleir, Department of Earth and are retracted posterior to the premaxillary ceous (Aptian, 120 million years ago) paleogeo- Environmental Sciences, University of Illinois at Chi- teeth (Fig. 2, A and D), as in Baryonyx (14). graphic map (Mollweide projection) with lati- cago, 845 West Taylor Street, Chicago, IL 60607, The unusually long, plate-shaped anterome- tude and longitude lines spaced at 30° intervals USA. D. Varricchio, Old Trail Museum, 823 North dial processes of the maxillae (18) are firmly (longitude greater than 120° is not shown) Main Avenue, Choteau, MT 59422, USA. G. P. Wilson, held by the premaxillae (Fig. 2B). The medial (31). White cross, fossil locality. (B) Maps University of California, Museum of Paleontology, showing Niger, the exposures of the GAD 5 1101 Valley Life Sciences Building, Berkeley, CA wall of the antorbital fossa is confined to the beds (12) (white, above; black, below), and the 94720, USA. anterior end of the antorbital fenestra, and a location of the holotypic skeleton of Suchomi- *To whom correspondence should be addressed. simple conical pneumatocoel extends anteri- mus tenerensis (16°259N, 9°79E). 1298 13 NOVEMBER 1998 VOL 282 SCIENCE www.sciencemag.org R EPORTS from that in Spinosaurus (1), in which the blade-shaped anterior trochanter, and the as- evolved convergently in neotetanurans and much deeper sail arches to an apex over the cending process of the astragalus is taller than spinosaurids or originated as a tetanuran sy- middorsal vertebrae (Fig. 4B). that in Allosaurus (20). napomorphy that was subsequently lost in Complete pectoral and pelvic bones show a Phylogenetic analysis (21, 22) links spi- torvosaurids (21, 22). deep subrectangular acromion on the scapula nosaurids with torvosaurids (23) and places Spinosaurids are characterized by numer- and a low obturator flange on the ischium. The this clade (Spinosauroidea) as the sister group ous derived features, many of which are re- distal end of the pubis is distinctive. Although to Neotetanurae (Fig. 4A and Table 2). The lated to piscivory [including an unusually there is a short, sagittal, symphyseal flange that derived features that are shared between spi- long snout with a long secondary palate; a may correspond with the pubic foot in other nosaurids and torvosaurids, including the terminal rosette of teeth in the upper and theropods, the flattened, subrectangular distal short forearm and the enlarged manual digit I lower jaws (25); subcylindrical, spaced end of the pubis faces anteriorly, perpendicular ungual (22), appear to have evolved by the crowns; posteriorly displaced external nares; to the sagittal plane (Fig. 3). The forearm is Middle Jurassic (Fig. 4B). A hook-shaped ventrally positioned basipterygoid articula- remarkably stout, and manual digit III is robust, coracoid characterizes Suchominus, Bary- tion; and other features (8, 13, 22)]. Our as seen in the size of metacarpal III and the third onyx, and neotetanurans but not torvosaurids analysis suggests that spinosaurids can be ungual (Fig. 3 and Table 1). The femur has a (24). Thus, the hook-shaped coracoid either divided into two clades, the Baryonychinae Fig. 2. Skull of the spi- nosaurid Suchomimus tenerensis. Articulated premaxillae and maxil- lae (MNN GDF501) in left (A) lateral (re- versed from right) and (B) ventral views. Skull reconstruction of S. te- nerensis based on re- mains from Niger and Baryonyx walkeri in (C) dorsal and (D) lat- eral views.