STUDENT OPPORTUNITIES THROUGH STEM PARTNERSHIPSChristopher Barrera Northglenn High School 601 W. 100th Ave. Northglenn, COReconstructing the paleoenvironments of the Cretaceous Morondava Basin, western Madagascar

ScienceScholars@dmns.org

Abstract: Little is known of the marine paleoenvironment of the Cretaceous period of the Morondava Basin. Many fossils that were discovered by the Denver Museum of Nature & Science in previous years were unable to be included in this research due to issues with local governments refusing to release them to be shipped overseas . Not having a complete fossil assemblage has made it very difficult to establish any strong conclusions and thus made it problematic in the identification of ancient environments that existed at that location.

Fig 1Cataloging the Sub Species.

Fig 1.2 Tooth of Squalicorax Curvatus

Fig 1.4 Recording fossil evidence after identification.

Fig 1.5 Identification process for Ptychodus Decurrens.

Fig 1.6 Identifying Ptychodus Marginalis.

Introduction:A collection of non-dinosaurian vertebrates from the Morondava Basin of western Madagascar was collected by teams from the University of Antananarivo, Madagascar and the Denver Museum of Nature & Science. These fossils include the remains of fish, rays, and sharks, specifically the fossil teeth of Ptychodus and Squalicorax .

Methods: Fossil vertebrates from the Morondava Basin, Madagascar were identified by the following methodology:

Morphology•Size •Shape•Serrations Taxonomy•Species•Sub Species•DietEcology•Habitat

Acknowledgements:I would like to thank the founders and donors of the Teen Science Scholars program. I’d also like to thank my Geology teacher Kent Hups for teaching me, guiding me and always helping me overcome my challenges, my parents for their love and support, Joe Sertich who has been a marvelous mentor, Adrian Paz for helping me draw the reconstruction and the Denver Museum of Nature and Science for giving me this once in a lifetime opportunity.

Fig 1.8 Attempting to identify the species by analyzing pieces of vertebrate.

Conclusions:Although there are not enough marine fossils to establish a strong conclusion, the current evidence suggests that Morondava basin was once rich and abundant with marine life. This reconstruction of the basin illustrates the diversity of the ancient marine life that once lived there. The large assemblage of shark and ray teeth suggests that there were enough fish and coral reefs to support a large oceanic community during the Cretaceous time period. Researchers and conservationists can use this information to develop possible protocols to protect and conserve life in our oceans and seas. As more fossil evidence is collected from Morondava basin, it will increase the knowledge of the paleoecology, and a greater understanding of the paleoenvironment.

Fig 1.9Unknown Species of fish Vertebrae.

Fig 2 Reconstruction of the paleoenvironment.

Fig 1.3Attempting to categorize sub species by the identification of serrations, size, and shape.

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Fig 1.7 Map of Western coast of Madagascar including Morondava Basin.

Comparative EcologyThe new fossil material consists of Shark and Ray teeth that have also been found in areas in North America such as: Texas, and Kansas. This is a great find because it enables the comparison between the ecology in each area. The Squalicorax (Fig 1, Fig 1.4) and Ptychodus (Fig 1.5, Fig 1.6) species have also been found in New Mexico’s Bainbridge River and northeast of Galisteo, Santa Fe county. It is also worthy to note that the fossils found in North America also date back to the Cretaceous time period. This finding can help understand the migration of these species and tell a lot about the preferred habitat in which they live.