Isalo II Formation (Makay Formation)

Anisian to Carnian

Faritany Toliara, Madagascar

Dinosaurs:

Theropoda indet.

Prosauropoda indet.

Sauropoda indet.

Other Animals:

Asteracanthus sp.

Osteichthyes indet.

Colobodontidae indet.

Semionotidae indet.

Stegocephali indet.

Metoposauridae

Metoposaurus hoffmani

Procolophonidae indet.

Reptilia indet.

Phytosauria indet.

Phytosauridae indet.

Rhynchosauria indet.

Unnamed rhynchosaur species

Isalorhynchus genovefae (including Hyperodapedon genovefae)

Azendohsaurus madagaskarensis

Archosauria indet.

Pseudosuchia indet.

Sphenodontia indet.

Synapsida indet.

Kannemeyeriiformes indet.

Chiniquodon kalanoro

Unnamed traversodontid species

Unnamed traversodontid species

Dadadon isaloi

Menadon besairiei

Notes:

Usually considered an ancient streambed, the Isalo Group likely represents a flooding event or series of events that overtook the valley during early Triassic colonization of the region. Although it contains what appears to be the tooth of a sauropod (Burmeister et al. 2006), Weishampel et al. (2007) listed only prosauropods for the formation and may have been indicating that the tooth, and possibly other teeth assigned to Theropoda, might be prosauropods, or that the confusing archosauromorph genus Azendohsaurus is a dinosaur. In all honesty, it is a little presumptive to assume these teeth belong to anything specifically. All the misidentification has contributed to confusion over the assigned epoch of the strata, but other genera certainly nail down a Triassic or possibly very early Jurassic date. Freshwater hybodontiform sharks were common along with giant salamander-like metoposaurs. On the land, dinosaurs were rare and, as of yet, no specific families have been identified. A few species of cynodonts, from herbivorous traversodonts to hunting Chiniquodon, were relatively common. It seems the bulky dicynodonts were even more rare than dinosaurs. The crazy Azendohsaurus seems to have had a little head, a long neck, and stump legs. As these weirdoes attest, bizarre reptiles dominated fauna. Crocodile-like phytosaurs made watering holes dangerous places and the pseudosuchians, crocs of the land, made terrestrial life equally uncomfortable.

References:

Burmeister, K. C., J. J. Flynn, J. M. Parrish, et A. R. Wyss. 2006. “Paleogeographic and biostratigraphic implications of new early Mesozoic vertebrates from Poamay, central Morondava Basin, Madagascar.” In J. D. Harris, S. G. Lucas, J. A. Spielmann, M. G. Lockley, A. R. C. Milner, et J. I. Kirkland. The Terrestrial Triassic-Jurassic Transition. New Mexico Museum of Natural History and Science Bulletin 37: 457-475.

Weishampel, D. B., P. M. Barrett, R. A. Coria, J. L. Loeuff, X. Xing, Z. Xijin, A. Sahni, E. M. P. Gomani, C. R. Noto. 2007. “Dinosaur Distribution.” In D. B. Weishampel, P. Dodson, and H. Osmólska. The Dinosauria, Second Edition. Berkeley, CA: University of California Press. 517-606.