Isalo II
Informal Triassic geological unit in Madagascar
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Isalo II, also known as the Makay Formation, is an informal Triassic geological unit in Madagascar.[1]
| Isalo II Formation | |
|---|---|
| Stratigraphic range: Ladinian-Carnian | |
| Type | Geological formation |
| Unit of | Isalo Group |
| Underlies | Isalo III Formation (unconformity) |
| Overlies | Isalo I Formation |
| Lithology | |
| Primary | Sandstone, mudstone |
| Location | |
| Coordinates | 20.3°S 45.4°E |
| Approximate paleocoordinates | 23.1°S 24.7°E |
| Region | Mahajanga & Toliara Provinces |
| Country | Madagascar |
| Extent | Morondava Basin, Mahajanga Basin |
  Isalo II (Madagascar) | |
It is described as "thick beds of mottled red or green clays associated with soft cross-bedded sandstones, light in colour and much finer-grained than the Isalo I sandstones." It is prominent in the Makay Massif.[2]
Fossil content
Amphibians
| Amphibians | ||
|---|---|---|
| Taxon | Material | Notes |
| Metoposauridae indet. | An interclavicle, skull fragments, and intercentra | Indeterminate metoposaurid remains similar to those of Indian metoposaurids. Some fossils were the basis for the dubious species "Metoposaurus hoffmani". May be from Isalo II or III.[3] |
| Stereospondyli indet. | Interclavicles | Indeterminate stereospondyl remains. May be from Isalo II or III.[3] |
Reptiles
| Synapsids | ||
|---|---|---|
| Taxon | Material | Notes |
| Archosauriformes sp. | Teeth, a coracoid, a centrum fragment, and cranial fragments | Various indeterminate fragments, some of which may belong to dinosaurs.[4] |
| Azendohsaurus madagaskarensis[5] | Numerous skulls and postcranial fossils[1] | An allokotosaurian archosauromorph,[6][7][1] originally mistakenly identified as a "prosauropod" dinosaur.[5] |
| Isalorhynchus genovefae | Numerous fossils representing parts of the skull and postcrania | A rhynchosaur sometimes considered a species of Hyperodapedon.[8] Possibly represents two taxa.[9] Reported sphenodontian[5] fossils are most likely juvenile rhynchosaurs instead.[10] |
| Kongonaphon kely[11] | A maxilla and postcranial material | A tiny lagerpetid avemetatarsalian[12] |
| Mambachiton fiandohana[13] | A partial skeleton | An armored basal avemetatarsalian[14] |
| Phytosauria indet. | Teeth | Similar to Rutiodon teeth.[4] |
| Procolophonidae sp. | A jaw fragment and other remains | An unnamed procolophonid parareptile[8] |
| Pseudosuchia indet. | Osteoderms | Likely referable to stagonolepid aetosaurs, though similar to goniopholidid crocodylomorphs as well.[4] |
| Silesauridae sp. | An unnamed silesaurid dinosauromorph[14] | |
Synapsids
| Synapsids | ||
|---|---|---|
| Taxon | Material | Notes |
| Chiniquodon kalanoro[15] | Part of a jaw | A chiniquodontid cynodont |
| Dadadon isaloi[16] | Several skulls and jaw fragments[17][18] | A massetognathine[18] traversodontid cynodont |
| Kannemeyeriiformes sp. | An unnamed kannemeyeriiform dicynodont[5][15][1] | |
| Menadon besairiei[16] | Skulls, jaws, and postcranial material[19] | A traversodontid cynodont |