Isalo II
| 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°18′S 45°24′E / 20.3°S 45.4°E |
| Approximate paleocoordinates | 23°06′S 24°42′E / 23.1°S 24.7°E |
| Region | Mahajanga & Toliara Provinces |
| Country |  Madagascar |
| Extent | Morondava Basin, Mahajanga Basin |
  Isalo II (Madagascar) | |
Isalo II, also known as the Makay Formation, is an informal Triassic geological unit in Madagascar.[1]
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
[edit]Amphibians
[edit]| 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
[edit]| 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
[edit]| 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 |
References
[edit]- ^ a b c d Nesbitt, S.J.; Flynn, J.J.; Pritchard, A.C.; Parrish, M.J.; Ranivoharimanana, L.; Wyss, A.R. (2015). "Postcranial osteology of Azendohsaurus madagaskarensis (?Middle to Upper Triassic, Isalo Group, Madagascar) and its systematic position among stem archosaur reptiles". Bulletin of the American Museum of Natural History. 398: 1–126. doi:10.1206/amnb-899-00-1-126.1. hdl:2246/6624. ISSN 0003-0090. S2CID 86289421.
- ^ Brenon, P. (1972). The Geology of Madagascar. In: Battistini, R., Richard-Vindard, G. (eds) Biogeography and Ecology in Madagascar. Monographiae Biologicae, vol 21. Springer, Dordrecht. https://doi.org/10.1007/978-94-015-7159-3_2
- ^ a b Fortuny, Josep; Arbez, Thomas; Mujal, Eudald; Steyer, J. Sébastien (2019-01-02). "Reappraisal of 'Metoposaurus hoffmani' Dutuit, 1978, and description of new temnospondyl specimens from the Middle–Late Triassic of Madagascar (Morondava Basin)". Journal of Vertebrate Paleontology. 39 (1): e1576701. Bibcode:2019JVPal..39E6701F. doi:10.1080/02724634.2019.1576701. ISSN 0272-4634. S2CID 146075668.
- ^ a b c Burmeister, Kurtis C.; Flynn, John J.; Parrish, J. Michael; Wyss, Andre R. (2006). "Paleogeographic and biostratigraphic implications of new early Mesozoic vertebrates from Poamay, central Morondava Basin, Madagascar". New Mexico Museum of Natural History & Science Bulletin. 37: 457–475.
- ^ a b c d Flynn, John J.; Parrish, J. Michael; Rakotosamimanana, Berthe; Simpson, William F.; Whatley, Robin L.; Wyss, André R. (1999-10-22). "A Triassic Fauna from Madagascar, Including Early Dinosaurs". Science. 286 (5440): 763–765. doi:10.1126/science.286.5440.763. ISSN 0036-8075. JSTOR 2899382. PMID 10531059.
- ^ Flynn, John; Nesbitt, Sterling; Parrish, Michael; Ranivoharimanana, Lovasoa; Wyss, Andre (2008). "A new species of basal archosauromorph from the Late Triassic of Madagascar". Journal of Vertebrate Paleontology. 28 (sup3): 78A.
- ^ Flynn, John J.; Nesbitt, Sterling J.; Parrish, J. Michael; Ranivoharimanana, Lovasoa; Wyss, André R. (2010). "A new species of Azendohsaurus (Diapsida: Archosauromorpha) from the Triassic Isalo Group of southwestern Madagascar: cranium and mandible". Palaeontology. 53 (3): 669–688. Bibcode:2010Palgy..53..669F. doi:10.1111/j.1475-4983.2010.00954.x. ISSN 1475-4983. S2CID 82341339.
- ^ a b Langer, Max; Boniface, Michael; Cuny, Gilles; Barbieri, Laurent (2000-04-01). "The phylogenetic position of Isalorhynchus genovefae, a Late Triassic rhynchosaur from Madagascar" (PDF). Annales de Paléontologie. 86 (2): 101–127. Bibcode:2000AnPal..86..101L. doi:10.1016/S0753-3969(00)80002-6. ISSN 0753-3969.
- ^ Whatley, R.L.; Flynn, J.J.; Parrish, J.M.; Simpson, W.; Wyss, A.R. (1999). "Isalorhynchus revisited: two rhynchosaur skeletons from southwestern Madagascar". Journal of Vertebrate Paleontology. 19 (sup3): 84A. JSTOR 4524027.
- ^ Langer, Max Cardoso (2005). "Studies on continental Late Triassic tetrapod biochronology. II. The Ischigualastian and a Carnian global correlation" (PDF). Journal of South American Earth Sciences. 19 (2): 219–239. Bibcode:2005JSAES..19..219L. doi:10.1016/j.jsames.2005.04.002. ISSN 0895-9811.
- ^ Kammerer, Christian F.; Nesbitt, Sterling J.; Flynn, John J.; Ranivoharimanana, Lovasoa; Wyss, André R. (2020-07-02). "A tiny ornithodiran archosaur from the Triassic of Madagascar and the role of miniaturization in dinosaur and pterosaur ancestry". Proceedings of the National Academy of Sciences. 117 (30): 17932–17936. Bibcode:2020PNAS..11717932K. doi:10.1073/pnas.1916631117. ISSN 0027-8424. PMC 7395432. PMID 32631980. S2CID 220386589.
- ^ Kammerer, Christian F.; Nesbitt, Sterling J.; Flynn, John J.; Ranivoharimanana, Lovasoa; Wyss, Andre (October 2019). "A new lagerpetid archosaur from the Triassic of Madagascar and the importance of miniaturization in ornithodiran evolution". Society of Vertebrate Paleontology Abstracts of Papers, 79th Annual Meeting: 127. Archived from the original on 2020-12-15. Retrieved 2020-06-27.
- ^ Nesbitt, Sterling J.; Patellos, Emily; Kammerer, Christian F.; Ranivoharimanana, Lovasoa; Wyss, Andre´ R.; Flynn, John J. (25 July 2023). "The earliest-diverging avemetatarsalian: a new osteoderm-bearing taxon from the Triassic (?Earliest Late Triassic) of Madagascar and the composition of avemetatarsalian assemblages prior to the radiation of dinosaurs". Zoological Journal of the Linnean Society. 199 (zlad038): 327–353. doi:10.1093/zoolinnean/zlad038.
- ^ a b Patellos, Emily A.; Nesbitt, Sterling J.; Kammerer, Christian F.; Wyss, Andre; Flynn, John J.; Ranivoharimanana, Lovasoa (October 2019). "A new reptile from the ?Middle Triassic of Madagascar may represent the earliest-diverging Avemetatarsalia (Archosauria)". Society of Vertebrate Paleontology Abstracts of Papers, 79th Annual Meeting: 167. Archived from the original on 2020-12-15. Retrieved 2020-06-27.
- ^ a b Kammerer, Christian F.; Flynn, John J.; Ranivoharimanana, Lovasoa; Wyss, André R. (2010-12-02). "The first record of a probainognathian (Cynodontia: Chiniquodontidae) from the Triassic of Madagascar". Journal of Vertebrate Paleontology. 30 (6): 1889–1894. Bibcode:2010JVPal..30.1889K. doi:10.1080/02724634.2010.520784. ISSN 0272-4634. JSTOR 25790814. S2CID 85868922.
- ^ a b Flynn, John J.; Parrish, J. Michael; Rakotosamimanana, Berthe; Ranivoharimanana, Lovasoa; Simpson, William F.; Wyss, André R. (2000-09-25). "New Traversodontids (Synapsida: Eucynodontia) from the Triassic of Madagascar". Journal of Vertebrate Paleontology. 20 (3): 422–427. doi:10.1671/0272-4634(2000)020[0422:NTSEFT]2.0.CO;2. ISSN 0272-4634. S2CID 130041740.
- ^ Ranivoharimanana, Lovasoa; Kammerer, Christian F.; Flynn, John J.; Wyss, André R. (2011-11-01). "New material of Dadadon isaloi (Cynodontia, Traversodontidae) from the Triassic of Madagascar". Journal of Vertebrate Paleontology. 31 (6): 1292–1302. Bibcode:2011JVPal..31.1292R. doi:10.1080/02724634.2011.618154. ISSN 0272-4634. JSTOR 41407685. S2CID 220437281.
- ^ a b Kammerer, Christian F.; Flynn, John J.; Ranivoharimanana, Lovasoa; Wyss, André R. (October 2012). "Ontogeny in the Malagasy Traversodontid Dadadon isaloi and a Reconsideration of its Phylogenetic Relationships". Fieldiana Life and Earth Sciences. 2012 (5): 112–125. doi:10.3158/2158-5520-5.1.112. ISSN 2158-5520. S2CID 84651546.
- ^ Kammerer, Christian F.; Flynn, John J.; Ranivoharimanana, Lovasoa; Wyss, André R. (2008-06-12). "New material of Menadon besairiei (Cynodontia: Traversodontidae) from the Triassic of Madagascar". Journal of Vertebrate Paleontology. 28 (2): 445–462. doi:10.1671/0272-4634(2008)28[445:NMOMBC]2.0.CO;2. ISSN 0272-4634. S2CID 140720709.