Isalo II explained

Isalo II Formation
Period:Carnian
Age:Ladinian-Carnian
Type:Geological formation
Prilithology:Sandstone, mudstone
Unitof:Isalo Group
Underlies:Isalo III Formation (unconformity)
Overlies:Isalo I Formation
Coordinates:-20.3°N 45.4°W
Paleocoordinates:-23.1°N 24.7°W
Region:Mahajanga & Toliara Provinces
Country: Madagascar
Extent:Morondava Basin, Mahajanga Basin

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

Amphibians

Amphibians
TaxonMaterialNotes
Metoposauridae indet.An interclavicle, skull fragments, and intercentraIndeterminate 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.InterclaviclesIndeterminate stereospondyl remains. May be from Isalo II or III.

Reptiles

Synapsids
TaxonMaterialNotes
Archosauriformes sp.Teeth, a coracoid, a centrum fragment, and cranial fragmentsVarious indeterminate fragments, some of which may belong to dinosaurs.[4]
Azendohsaurus madagaskarensis[5] Numerous skulls and postcranial fossilsAn allokotosaurian archosauromorph,[6] [7] originally mistakenly identified as a "prosauropod" dinosaur.
Isalorhynchus genovefaeNumerous fossils representing parts of the skull and postcraniaA rhynchosaur sometimes considered a species of Hyperodapedon.[8] Possibly represents two taxa.[9] Reported sphenodontian fossils are most likely juvenile rhynchosaurs instead.[10]
Kongonaphon kely[11] A maxilla and postcranial materialA tiny lagerpetid avemetatarsalian[12]
Mambachiton fiandohana[13] A partial skeletonAn armored basal avemetatarsalian[14]
Phytosauria indet.TeethSimilar to Rutiodon teeth.
Procolophonidae sp.A jaw fragment and other remainsAn unnamed procolophonid parareptile
Pseudosuchia indet.OsteodermsLikely referable to stagonolepid aetosaurs, though similar to goniopholidid crocodylomorphs as well.
Silesauridae sp.An unnamed silesaurid dinosauromorph

Synapsids

Synapsids
TaxonMaterialNotes
Chiniquodon kalanoro[15] Part of a jawA chiniquodontid cynodont
Dadadon isaloi[16] Several skulls and jaw fragments[17] [18] A massetognathine traversodontid cynodont
Kannemeyeriiformes sp.An unnamed kannemeyeriiform dicynodont
Menadon besairieiSkulls, jaws, and postcranial material[19] A traversodontid cynodont

Notes and References

  1. 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. 10.1206/amnb-899-00-1-126.1. 0003-0090. free. 2246/6624. 86289421.
  2. 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
  3. 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. 10.1080/02724634.2019.1576701. 2019JVPal..39E6701F . 146075668. 0272-4634.
  4. 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.
  5. 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. en. 286. 5440. 763–765. 10.1126/science.286.5440.763. 2899382. 0036-8075. 10531059.
  6. 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.
  7. 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. en. 53. 3. 669–688. 10.1111/j.1475-4983.2010.00954.x. 2010Palgy..53..669F . 82341339 . 1475-4983. free.
  8. Langer. Max. Boniface. Michael. Cuny. Gilles. Barbieri. Laurent. 2000-04-01. The phylogenetic position of Isalorhynchus genovefae, a Late Triassic rhynchosaur from Madagascar. Annales de Paléontologie. en. 86. 2. 101–127. 10.1016/S0753-3969(00)80002-6. 2000AnPal..86..101L . 0753-3969.
  9. 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. 4524027.
  10. Langer . Max Cardoso . 2005 . Studies on continental Late Triassic tetrapod biochronology. II. The Ischigualastian and a Carnian global correlation . Journal of South American Earth Sciences . 19 . 2 . 219–239 . 10.1016/j.jsames.2005.04.002 . 2005JSAES..19..219L . 0895-9811.
  11. 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. en. 10.1073/pnas.1916631117. 32631980. 220386589. 0027-8424. 7395432. 2020PNAS..11717932K . free .
  12. 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. 2020-06-27. 2020-12-15. https://web.archive.org/web/20201215024254/http://vertpaleo.org/Annual-Meeting/Annual-Meeting-Home/SVP-Program-book-v5_w-covers.aspx#page=128. dead.
  13. 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 . 10.1093/zoolinnean/zlad038. free .
  14. 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) . dead . Society of Vertebrate Paleontology Abstracts of Papers, 79th Annual Meeting . 167 . https://web.archive.org/web/20201215024254/http://vertpaleo.org/Annual-Meeting/Annual-Meeting-Home/SVP-Program-book-v5_w-covers.aspx#page=168 . 2020-12-15 . 2020-06-27.
  15. 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. 10.1080/02724634.2010.520784. 25790814. 2010JVPal..30.1889K . 85868922. 0272-4634.
  16. 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. 10.1671/0272-4634(2000)020[0422:NTSEFT]2.0.CO;2. 130041740 . 0272-4634.
  17. 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. 10.1080/02724634.2011.618154. 41407685. 2011JVPal..31.1292R . 220437281. 0272-4634.
  18. 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. 10.3158/2158-5520-5.1.112. 84651546. 2158-5520.
  19. 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. 10.1671/0272-4634(2008)28[445:NMOMBC]2.0.CO;2. 140720709 . 0272-4634.

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Isalo II".

Except where otherwise indicated, Everything.Explained.Today is © Copyright 2009-2024, A B Cryer, All Rights Reserved. Cookie policy.