See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/285347338 Dryosaurus and Camptosaurus, intercontinental genera of Upper Jurassic ornithopod dinosaurs Article · January 1980 CITATIONS READS 19 73 1 author: Peter Galton University of Bridgeport 158 PUBLICATIONS 4,153 CITATIONS SEE PROFILE Some of the authors of this publication are also working on these related projects: Cranial and postcranial anatomy of ornithischians Camptosaurus and Stegosaurus based on O.C. Marsh's material collected in the 1880s from the Morrison Formation of western USA View project All content following this page was uploaded by Peter Galton on 06 August 2016. The user has requested enhancement of the downloaded file. Mdm. Soc. gdol. Fr., N.S., 1980, no 139, p. 103-108. Dryosaurus and Camptosaurus, intercontinental genera of Upper Jurassic ornithopod dinosaurs by PETERM. GALTON * Abstract. - The IZimmeridgian (Upper Jurassic) ornithopod dinosaurs Dryosaurus and Camptosaurus occur in western North America (D. altus, C. dispar), western Europe (C. prestwichii, C. sp.) and East Africa (D. lettowuorbecki). The hypsilophodontids Dryosaurus altus and D. lettowvorbeclci are almost conspecific and this extreme similari-ty indicate the presence of a land connec.tion between northern Laurasia and southern Gondwanaland sometime in the Icimmeridgian (middle Upper Jurassic). The only correct referrals of European specimens to the North American iguanodontid genus Camptosaurus are .the nearly comple-te slieleton of C. prestwichii (HULICE)from England and a newly described femur from Portugal. The skeletons of the North American and European species of Camptosaurus differ in several respects and this probably indicates the presence of a land connection sometime in the Oxfordian (lower Upper Jurassic). The land connections were probably different with that for Dryosaurus being across the western end of the central Atlantic and that for Camptosaurus bei,nng across the North Atlantic epicontinental seaway. Dryosaurus et Camptosaurtas, genres intercontinentaux de Dilnosaures ornithopodes du Jurassique superieur RisumC. - Les Dinosauriens ornithopodes kimmeridgiens (Jwassique supkrieur) Dryosaurus el Camptosaurus sont connus dans l'0uest de I'Amerique du Nord (D. altus, C. dispar), en Europe occidentale (C. prestwichii, C. sp.) et en Afrique orientale (D. lettowvorbecki). Les Hypsilo- phodontides Dryosaurus altus et D. lettowvorbecki sont presque conspecifiques et cette extr&me similaritk indique la prdsence d'une connexion terrestre entre la Laurasie au Nord et le Gondwana au Sud a un moment du Kimmeridgien (milieu du Jurassique supirieur). Les seuls specimens europeens rapport& avec raison au genre d'lguanodontide nord-amkricain Cumptosaurus sont le squelette presque complet de C. presfwichii (HULKE)d'Angleterre et un femur du Portugal recemment decrit. Les squelettes des espkces nord-amkricaines et europkennes de Cumptosaurus different 2? plusieurs points de vue et ceci indique probablement la presence d'une connexion terrestre a un momenl de l'oxfordien (dkbut du Jurassique superieur). Ces connexions terrestres ktaient probablement differentes, celle pour Dryosaurus se trouvant au travers de l'extremitd occidentale de l'Atlantique central, et celle pour Camptosaurus se pla~anth. travers le bras de mer epicontinental nord-atlantique. Druosaurus. horizon and continent then it would all be referred to Dryosaurus altus. Janensch [l9551 described much of the ornithopod The skulls of the two species of Dryosaurus are very material from the Tendaguru Beds (Upper Jurassic, Upper distinct from those of other hypsilophodontids and show Kimmeridgian = Lower Tithonian [Hallam, 19751) of only a few diflerences (fig. 1A-D), some of which (posterior Tanzania, East Africa. He referred it all to Dysalotosaurus region, fig. 1A, C ; width fig. lB, D) result from crushing Zettow-vorbecki POMPECICJ[l9201 that, as shown by Galton of the Morrison skull. In addition, two skulls of Hypsilo- [l977 a], is referable to the genus Dryosaurus MARSH phodon foxii show greater differences in sutural pattern (1894) that was previously unknown outside of the anteroventral to the orbit (fig. 3 A, B ; Galton [1974]) than Morrison Formation (Upper Kimmeridgian) of the western do those of Dryosaurus (fig. lA, C). The main character interior of the United States of America. The correct that distinguishes the skull of Dryosaurus altus from that name for the Tendaguru hypsilophodontid is Dryosaurus of D. lettowuorbecki is the difference in length of the supsa- Zettowvorbecki (VIRCHOW,1919) [Galton in press a]. The orbital (fig. lA, C). The crowns of the teeth are lozenge- type material (YPM 1876, 1884, not YPM 1915 as given shaped (figs. 1E-H, 2E-G) with the central ridge of a by Galton [l977 a, b]) of Laosaurus altus MARSH(1878), maxillary tooth (fig. lE, G) being as prominent as that of the type species of the genus Dryosaurus MARSH(1894), a dentary tooth (figs. IF, I-I, 2E-G). The deltopectoral will be described elsewhere with supplementary infor- crest of the humerus is low (fig. 11-L). In the pelvic girdle mation on D. Zettowvorbecki [Galton, in press a]. the main body of the ilium is low with an obliquely trun- Hypsilophodontid dinosaurs are particularily suitable cated posterior end (fig. 1M-P) and the brevis shelf is for paleobiogeographic work because the forms of the broad (Q. IN, 0) ; the obturator process of the ischium skull, teeth, pelvis and femur is distinctive for each genus. is proximally placed and the distal half is curved and bar- Dryosaurus is especially important because both species shaped (fig. IM, N) ; and the anterior process of the are well represented (figs. 1A-Y, 2E-G), so that almost pubis is slender with a variably developed ventrolateral the complete anatomy plus some data on individual edge (figs. lM, N, Q, R). The femora (fig. IS-W) possess variation (fig. 1I-W) is documentable for each species the following suite of characters : a deep cleft separating [Galton, in press a]. The diflerences between the two the lesser and greater trochanters (fig. IS, T) ; the deep species of Dryosaurus (figs. 1A-Y, 2E-G) are minor [Galton, depression level with the proximally placed fourth tro- in press a] when one considers three points. Firstly, there chanter is set well anteriorly on the shaft (fig. IS, T) ; is an extremely long distance between the two localities distally (fig. IS-W) the medial edges of the medial condyles even when the continents are reassembled in their Upper are squared off, there is an anterior intercondyle groove, Jurassic positions (over 11,000 km ; see maps in Hallam and the posterior lateral condyle is thin. In the pes, the [1975, 19771, Galton [l977 a, b]). Secondly; -%hew-a-r-e- first m-eta"carsar is-rudimentary -sethere were only three almost as many differences between individuals of the movable toes (fig. lX, Y). Lower Cretaceous Hypsilophodon foxii (fig. 3 ; Galton An incomplete tibia (fig. 25, K) from the Lower Oxford [1974]), all the material of which came from a bed less Clay (Callovian, upper Middle Jurassic) near Peterborough, than 1 m thick in a 0,s km length of sea cliff in southern England. Thirdly, each species shows a similar range of individual variation for those elements that are well repre- * Department of Biology, University of Bridgeport, Bridgeport, sented (e.g. humerus, ilium, pubis, femur, fig. 1 I-W, Ct. 06602, U.S.A. Galton in press a). If this material all came from the same Note presentee a la seance du 5-9 septembre 1978. P. M. GALTON FIG. 1. - Comparative anatomy of hypsilophodontid dinosaurs Dryosaurus alfus (MARSH,1878) from Morrison Formation of western U.S.A. (A, B, G-J, M, 0, Q, S, U, V, X ; identifying letters underlined to facilitate comparisons) ; Dryosaurus Ieffowvorbeeki (Vr~c~ow,1919) from Tendaguru Beds of East Africa (C-F, K, L, N, P, R, T, W, Y) ; and holotype of Valdosaurus eanalieulafus (GALTON,1975) from Wealden (Lower Cretaceous) of England (Z) in lateral view (A, C, E, G, I-R), medial view (F, H, S, T, Z), dorsal view (B, D, N, 0, X, Y) and/or distal ends (I, K, L, S-W, Z). All bones drawn as if from left side except medial views with distal views that are from right side. A, skull of CM 3392 with quadrate YPM 1876 ; B, skull CM 3392, C, D, skull HMN dyA, modified after Janensch [l9551 ; E, slightly worn maxillary tooth after Janensch [l9551 ; F, moderately worn dentary tooth after Janensch [l9551 ; G, unworn maxillary tooth YPM 1876 ; H, unworn dentary tooth YPM 1876 ; I, hume- rus YPM 1876 ; J. humerus AMNH 834 ; K, humerus UT 1495122 ; L, humerus UP 1495123 ; M, pelvic girdle AMNH 834 ; N, reconstruction of pelvic girdle (HMN dyI, dyII, dy35) with dorsal view of ilium (HMN dyII) : 0, ilium DNM 1016 in dorsal and lateral views ; P, ilium UT 149519 ; Q, pubis YPM 1884 ; R, pubis UT 149516 ; S, femur YPM 1876 ; T, femur HMN dy 36 ; U, femur CM 21786 ; V, femur AMNH S34 ; W, femur UT 1495114 ; X, pes CM 21786 ; Y, pes HMN dyV ; Z, femur BMNH R185, after Galton 119751. Abbreviations :a, anterior intercondylar groove ; ap, anterior process of pubis ;b, brevis shelf ; d, deltopectoral crest ; f, fourth trochanter ; g, greater trochanter ; i, ilium ; is, ischium ; 1, lesser trochanter ; m, depression for M. caudi-femoralis longus ; o, obturator process ; p, pubis ; S, supraorbital; 1, vestigal first metatarsal. Scale lines represent 5 cm (A-D, 1-2) or 1 cm (E-H), from Galton [l977 b]. England is similar to that of the holotype of Dryosaurus Gilmore [l9091 provisionally accepted C. prestwichii alfus but this specimen is probably generically and speci- (HULRE)as a valid species of Camptosaurus on the basis fically indeterminate [Galton, 1977 b] and it may be of the original description in which most of the skeleton referable to (( Camptosaurus s Zeedsi LYDEKKER(1889) was not illustrated.