the occurrence and geological setting of cretaceous dinosaurs

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J. Paleont. Soc. Korea. Vol. 22, No. 1, 2006al., 2004:2), no evidence for the age is provided. Taquet (1976), on which the dating of fossil localities inNiger appears to rely, places the Echkar Formation in the Albian. By the Late Cenomanian, marine transgressionhad put an end to the deposition of the Continentale Intercalaire, of which the Echar Formationis a part. Until chronological data are brought forth to justify a Cenomanian age for Rugops, its significancefor indicating trans-Atlantic interchange at 95 Ma should be questioned because that age estimatestands contrary to indications that the Atlantic was complete by Albian time (which ended at 99.6Ma), and Niger was inundated by marine waters by Late Cenomanian time, or about at the target age of95 Ma.We began this paper by stating that we have embarked on what we hope will be a long-termfield-based exploration of the vertebrate paleontology of Angola. During the course of writing this paperseveral specific issues became obvious as to what can be done and what should be done with respect toour project. From what we know now, it is clear that the fossil record of mosasaurs, plesiosaurs, and turtlescan be significantly augmented through field work in Angola, and that those studies will have an impacton phylogenetic studies of those groups. Advances will take place on fossils from at least two timehorizons, the first approximately the Late Turonian and the second Campanian-Maastrichtian. We acceptthat statement as likely because we have collected fossils in those intervals, but that does not preclude thediscovery of fossils at other stratigraphic levels. It is also a reasonable assumption that we will obtain abetter sample of dinosaurs and other terrestrial fossils.All of the fossils that we collect are likely to influence models of biogeography of marine vertebrateson the one hand, and of terrestrial vertebrates on the other, because of the strategic position of Angolawith respect to the completion of the Atlantic Ocean permitting the exchange of Northern with SouthernHemisphere marine species in a strictly circumscribed area both temporally and geographically, and becausethe completion of the Atlantic Ocean resulted in the final isolation of Africa and its terrestrialfauna. To approach its full potential with respect to formulating and testing biogeographic models, however,it has become abundantly clear that fossils need to be collected with extreme concern for stratigraphiccontext, and that multiple approaches to chronological control, including radiometric dating,should be applied.The reconnaissance field trip in May of 2005 was funded by the Institute for the Study of Earth andMan at Southern Methodist University. We gratefully acknowledge Eduardo Morais, Fernando Caliki,and Abílio Fernandes of the Unversidade Agostinho Neto in Luanda, and Maria Vitória Vandule of theInstituto Geológico de Angola in Lubango for help and assistance. We also thank Luís Rocha, RosárioSarzedas, Álvaro Baptista, Pedro Serrano, and Margarida Ventura for their support in the field. DianaVineyard provided critical comments and editorial assistance. Kent Newman aided in specimenpreparation. Peter Vail very kindly made important references available to us, as did Ben Kear. DaleWinkler, Anthony Fiorillo, Qiang Ji, and Philip J. Currie reviewed the manuscript. We are especiallygrateful to Yuong-Nam Lee of the Korea Institute of Geoscience and Mineral Resources for the invitationto present this study at the 2006 Goseong International Dinosaur Symposium.
Jacobs et al. - Cretaceous vertebrates from Angola앙골라에서 산출된 백악기 공룡 모사사우루스 수장룡 거북과그 지질환경 á í 1 Department of Geological Sciences, Southern Methodist University, Dallas, TX, 75275, USA,2 Departamento de Ciências da Terra, FCT, Universidade Nova de Lisboa, Lisbon, Portugal3 Museu da Lourinhã, Rua João Luis de Moura, 2530-157 Lourinhã, Portugal,4 Natuurhistorisch Museum Maastricht, de Bosquetplein 6, NL-6211 KJ Maastricht, The Netherlands,5 Faculty of Earth and Life Sciences, Vrije Universiteit Amsterdam, The Netherlands6 Academia de Ciências de Lisboa, Rua da Academia das Ciências, Lisboa, Portugal,7 Universidade Agostinho Neto, Luanda, Angola8 Université de Bourgogne, Dijon, France요 약: 아프리카 사하라 지역에 척추동물화석을 배태한 백악기 지층의 노출은 매우 적다. 왜냐하면 대륙의 상당 부분을 선캄브리아기 변성암 육괴가 넓게 분포하고 있을 뿐 아니라 젊은 시대의 지층들과 식물들이 이들 백악기 지층을 덮고 있기 때문이다. 그러나 백악기 해성층과 육성층이 넓게 발달한 지역이 앙골라 해안과 내륙 사이에서 발견되었다. 앙골라의 주변부는 곤드와나 대륙이 갈라지면서 남대서양이 확장되는 것과 관련되어 형성되었다. 백악기 퇴적층은 해양지각의 덮고 있어 시대는 매우 제한적이며 가장 오래된 지층은 지자기대 (magnetozone) M3 (대략 128Ma, Barremian)보다 오래되지 않았다. 얕은 해양퇴적 환경은 해안가에 드러나 있지만 내륙으로 점점 육성퇴적 환경이 증가한다. 상어화석이외에는 앙골라에서 척추화석이 거의 발견되지 않았었다. 예외적인 화석은 앙골라 북부에서 산출된 후기Turonian 모사사우루스 Angolasaurus bocagei 와 Tylosaurus iembeensis 이다. 이들 화석은 가장 초창기에 진화된 모사사우루스들이기 때문에 중요하다. 최근 야외조사를 통해 새로운 Angolasaurus 의 머리뼈뿐만 아니라 상어, 물고기,수장룡, 새로운 거북의 머리뼈, 앙골라에서는 처음 발견되는 용각류의 앞다리가 발견되었다. 앙골라 남부에는 백악기에서 팔레오세 경계까지 퇴적된 해양퇴적층이 발견된다.주요어 백악기, 공룡, 모사사우루스, 수장룡, 거북, 앙골라Ala, M. A. and Selley, R. C. 1997. The western African coastal basins; pp. 173-186 in Selley, R. C. (ed.) and Hsu, K.J.(series ed.), African Basins (Sedimentary Basins of the World, 3). Elsevier Science, Saint Louis, Missouri.Antunes, M. T. 1964. O neocretácico e o cenozóico do litoral de Angola. Junta de Investigações do Ultramar, Lisboa,254 pp.Antunes, M. T. 1966. Contribuiçã para o conhecimento dos nautilóides fóssies de Angola. Conclusões estratigráficassobre o Cretácico terminal da Bacia de Moçåmede, a propósito dos dos cefalópodes de S. Nicolau. Garcia de Orta(Lisboa) 14:109-138.Antunes, M. T. and Cappetta, H. 2002. Sélaciens du Crétacé (Albien-Maastrichtien) d’Angola. Palaeontographica264:85-146.Bardet, N., Pereda Superbiola, X., Iarochène, M., Amalik, M. and Bouya, B. 2005. Durophagous Mosasauridae(Squamata) from the Upper Cretaceous phosphates of Morocco. Netherlands Journal of Geosciences 84:167-175.Bell, G. L., Jr. 1997. Part IV Mosasauridae. Introduction; pp. 281-292 in Callaway, J. M. and Nicholls, E. L. (eds.), AncientMarine Reptiles. Academic Press, San Diego.Bell, G. L., Jr. 1997. A phylogenetic revision of North American and Adriatic Mosasauroidea; pp. 293-332 in Callaway,J. M. and Nicholls, E. L. (eds.), Ancient Marine Reptiles. Academic Press, San Diego.Bell, G. L., Jr. and Polcyn, M. J. 2005. Dallasaurus turneri, a new primitive mosasauroid from the middle Turonian
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