Manda Formation

The Manda Formation (also known as the Manda Beds) is a Middle Triassic (Anisian?) or possibly Late Triassic (Carnian?) geologic formation in Tanzania. It preserves fossils of many terrestrial vertebrates from the Triassic, including some of the earliest dinosauromorph archosaurs.[1] The formation is often considered to be Anisian in age according to general tetrapod biochronology hypotheses and correlations to the Cynognathus Assemblage Zone of South Africa.[2] However, some recent studies cast doubt to this age, suggesting that parts deposits may actually be younger (Carnian) in age.[3][4][5]

Manda Formation
Stratigraphic range:
Map of the outcropping Manda Formation
TypeGeological formation
Unit ofSongea Group
Sub-unitsKingori Sandstone Member, Lifua Member
UnderliesNone
OverliesUsili Formation
Lithology
PrimarySandstone
OtherMudstone, siltstone, marl
Location
Coordinates10.3°S 35.2°E / -10.3; 35.2
Approximate paleocoordinates53.7°S 23.0°E / -53.7; 23.0
RegionIringa & Ruvuma Regions
Country Tanzania
ExtentRuhuhu Basin
Manda Formation is located in Tanzania
Manda Formation
Manda Formation (Tanzania)

History of study

One of the first to study rocks of the Manda Formation was British geologist G. M. Stockley. In 1932, Stockley explored the geology of the Ruhuhu Basin in Tanzania. He called a series of layers dating from the Late Carboniferous to the Middle Triassic the Songea Series and divided it into eight units labelled K1-K8. Stockley was also the first to describe fossils from these rocks, naming an older layer the "Lower Bone Bed" and a younger layer the "Upper Bone Bed".

In 1957, paleontologist Alan J. Charig described many more fossils from the bone beds in his Ph.D. thesis for the University of Cambridge.[6][7] Charig renamed the youngest of Stockley's units in 1963, calling unit K6 the Kawinga Formation, K7 the Kingori Sandstones, and K8 the Manda Formation. Fossils were identified in many strata, invalidating Stockley's division into two distinct bone beds. Since Charig's description, the Kawinga Formation has been renamed the Usili Formation, the Kingori Sandstones have become the Kingori Sandstone Member of the Manda Formation, and Charig's original Manda Formation has become a subunit of the formation called the Lifua Member.[1] Six formations and one informal unit are currently recognized in the Songea Group (Ruhuhu basin) rocks range in age from Pennsylvanian to Anisian, including the Idusi (K1), Mchuchuma (K2), Mbuyura (K3), Mhukuru (K4), Ruhuhu (K5), and Usili (K6) formations and the informal Manda Beds, which include the Kingori Sandstone (K7) and Lifua Member (K8).[8]

Paleobiota

Tetrapods
Color key
Taxon Reclassified taxon Taxon falsely reported as present Dubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon
 Notes
Uncertain or tentative taxa are in small text; crossed out taxa are discredited.

Temnospondyls
TaxonSpeciesMemberMaterialNotesImages
Stanocephalosaurus S. pronus[9]LifuaRemains of a temnospondyl amphibian previously referred either to Parotosuchus or Eryosuchus[10]

Parareptiles
TaxonSpeciesMemberMaterialNotesImages
Ruhuhuaria R. reiszi[11]LifuaCAMZM T997, poorly preserved but complete skull and mandibleAn owenettid

Archosauromorphs
TaxonSpeciesMemberMaterialNotesImages
Asperoris Asperoris mnyamaLifuaNHMUK PV R36615, incomplete skullA non-crurotarsan archosauriform of uncertain phylogenetic placement
Stagonosuchus S. tanganyikaensis[12]Lifua MemberSAM 11754, right humerusAn indeterminate archosauromorph; possibly a rhynchosaur
Stenaulorhynchus S. stockleyiLifuaA rhynchosaur
Unnamed Archosauromorph[9] Indeterminate. LifuaNHMUK PV R36619, incomplete skull and partial postcranial skeletonA non-archosaurian archosauriform
Archosaurs
TaxonSpeciesMemberMaterialNotesImages
Asilisaurus A. kongweLifuaA silesaurid dinosauriform
Hypselorhachis H. mirabilisLifuaNHMUK R16586, a complete dorsal vertebraA sail-backed archosaur possibly belonging to the family Ctenosauriscidae
Mambawakale M. ruhuhu[13]Lifua MemberNHMUK R36620, partial skull and some postcranial fragmentsA paracrocodylomorph; previously informally known as "Pallisteria angustimentum".
Mandasuchus M. tanyauchen[14]Lifua MemberNHMUK R6792, partial mandible and postcranial skeletonsA paracrocodylomorph
Nundasuchus N. songeaensis[9][15]LifuaNMT RB48, partial skeleton and skullAn archosaur, possibly suchian
Nyasasaurus N. parringtoni[2]LifuaNHMUK R6856, a right humerus, three partial presacral vertebrae and three sacral vertebrae. SAM-PK-K10654 is also potentially referable - see "Thecodontosaurus" alophos below.A theropod or an ornithischian or the most advanced non-dinosaurian dinosauriform. Possibly the oldest dinosaur.[2]
Teleocrater T. rhadinusLifuaNHMUK R6795, vertebrae, limb bones and other elements. Additional material referred from two other individuals.An early avemetatarsalian[16]
"Thecodontosaurus" "T." alophos[2] Lifua MemberSAM-PK-K10654, three neck vertebrae and two rear presacral vertebraeA probable subjective senior synonym of Nyasasaurus, first identified as a sauropodomorph dinosaur.[2]
Unnamed archosaur[17] Unidentified. LifuaNearly complete skull and partial skeletonA stem-aetosaur
Dicynodonts
TaxonSpeciesMemberMaterialNotesImages
Angonisaurus A. cruickshankiLifuaA kannemeyeriiform
Kannemeyeria K. simocephalusLifuaA kannemeyeriid kannemeyeriiform
Sangusaurus S. parringtoniiLifuaA stahleckeriid kannemeyeriiform
Shansiodon Indeterminate LifuaSkullA shansiodontid kannemeyeriiform
Tetragonias T. njalilusLifuaA shansiodontid kannemeyeriiform
Cynodonts
TaxonSpeciesMemberMaterialNotesImages
Aleodon A. brachyrhamphusLifuaA possible chiniquodontid
Cricodon C. metabolusLifuaA trirachodontid
Cynognathus C. crateronotus[18]LifuaA cynognathid
Diademodon D. tetragonasLifuaA diademodontid
Scalenodon S. angustifronsLifuaA traversodontid
S? attridgeiLifuaA traversodontid; may fall outside the genus Scalenodon and may be a synonym of "Scalenodon" charigi
S? charigiLifuaA traversodontid; may fall outside the genus Scalenodon
Mandagomphodon M. hirschoniLifuaA traversodontid; originally classified in the genus Scalenodon; named after the Manda Beds

Age and correlations

The upper Manda Beds have been assigned to the Perovkan LVF based on reports that Eryosuchus,[19] Shansiodon,[20] Angonisaurus, and Scalenodon[21] were present.[22] Angonisaurus does seem to tie the Manda Beds to subzone C of the Cynognathus Assemblage Zone in the Karoo Basin.[23] However, the relations of the other Tanzanian taxa are more ambiguous. Purported Tanzanian "Eryosuchus" and "Shansiodon" specimens likely represent new genera unrelated to their supposed namesakes,[24][23] while Scalenodon may be endemic to Africa due to the uncertain relations of non-African "Scalenodon" species.[25] One Upper Manda cynodont, Aleodon, has also been found in the Dinodontosaurus assemblage zone of the Santa Maria Formation in Brazil.[26]

See also

References
  1. Butler, R. J.; Barrett, P. M.; Abel, R. L.; Gower, D. J. (2009). "A possible ctenosauriscid archosaur from the Middle Triassic Manda Beds of Tanzania". Journal of Vertebrate Paleontology. 29 (4): 1022–1031. doi:10.1671/039.029.0404. S2CID 86267617.
  2. Nesbitt, S. J.; Barrett, P. M.; Werning, S.; Sidor, C. A.; Charig, A. J. (2013). "The oldest dinosaur? A Middle Triassic dinosauriform from Tanzania". Biol. Lett. 9 (1): 20120949. doi:10.1098/rsbl.2012.0949. PMC 3565515. PMID 23221875.
  3. Nesbitt, S; Butler, R; Ezcurra, M; Charig, A; Barrett, P (2020-07-08). "The anatomy of Teleocrater rhadinus, an early avemetatarsalian from the lower portion of the Lifua Member of the Manda Beds (Middle Triassic) (project)". MorphoBank datasets. doi:10.7934/p3173. S2CID 226195075. Retrieved 2021-11-25.
  4. Marsicano, Claudia A.; Irmis, Randall B.; Mancuso, Adriana C.; Mundil, Roland; Chemale, Farid (2015-12-07). "The precise temporal calibration of dinosaur origins". Proceedings of the National Academy of Sciences. 113 (3): 509–513. doi:10.1073/pnas.1512541112. ISSN 0027-8424. PMC 4725541. PMID 26644579.
  5. Ottone, Eduardo G.; Monti, Mariana; Marsicano, Claudia A.; de la Fuente, Marcelo S.; Naipauer, Maximiliano; Armstrong, Richard; Mancuso, Adriana C. (December 2014). "A new Late Triassic age for the Puesto Viejo Group (San Rafael depocenter, Argentina): SHRIMP U–Pb zircon dating and biostratigraphic correlations across southern Gondwana". Journal of South American Earth Sciences. 56: 186–199. doi:10.1016/j.jsames.2014.08.008. hdl:11336/85022. ISSN 0895-9811.
  6. Charig, A. J. (1957). New Triassic archosaurs from Tanganyika, including Mandasuchus and Teleocrater: Dissertation Abstracts. Cambridge University.
  7. Nesbitt, S. J.; Butler, R. J. (2012). "Redescription of the archosaur Parringtonia gracilis from the Middle Triassic Manda beds of Tanzania, and the antiquity of Erpetosuchidae". Geological Magazine. 150 (2): 225–238. doi:10.1017/S0016756812000362. S2CID 129115107.
  8. Sidor, C. A.; Angielczyk, K. D.; Weide †, D. M.; Smith, R. M. H.; Nesbitt, S. J.; Tsuji, L. A. (2010). "Tetrapod fauna of the lowermost Usili Formation (Songea Group, Ruhuhu Basin) of southern Tanzania, with a new burnetiid record". Journal of Vertebrate Paleontology. 30 (3): 696–703. doi:10.1080/02724631003758086. S2CID 55397720.
  9. Sidor, C. A.; Vilhena, D. A.; Angielczyk, K. D.; Huttenlocker, A. K.; Nesbitt, S. J.; Peecook, B. R.; Steyer, J. S.; Smith, R. M. H.; Tsuji, L. A. (2013). "Provincialization of terrestrial faunas following the end-Permian mass extinction". Proceedings of the National Academy of Sciences. 110 (20): 8129–8133. doi:10.1073/pnas.1302323110. PMC 3657826. PMID 23630295.
  10. Sues, H.-D.; Fraser, N.C. (2010). "Early and early Middle Triassic in Gondwana". Triassic Life on Land: The Great Transition. New York: Columbia University Press. pp. 19–36. ISBN 9780231135221. ISBN 0-231-13522-X
  11. Tsuji, L. A.; Sobral, G.; Müller, J. (2013). "Ruhuhuaria reiszi, a new procolophonoid reptile from the Triassic Ruhuhu Basin of Tanzania". Comptes Rendus Palevol. 12 (7–8): 487–494. doi:10.1016/j.crpv.2013.08.002.
  12. Lautenschlager, S.; Desojo, J. B. (2011). "Reassessment of the Middle Triassic rauisuchian archosaurs Ticinosuchus ferox and Stagonosuchus nyassicus". Paläontologische Zeitschrift. 85 (4): 357–381. doi:10.1007/s12542-011-0105-1. S2CID 86671911.
  13. Butler, R.J.; Fernandez, V.; Nesbitt, N.J.; Leite, J.V.; Gower, D.J. (2022). "A new pseudosuchian archosaur, Mambawakale ruhuhu gen. et sp. nov., from the Middle Triassic Manda Beds of Tanzania". The Royal Society. 9 (2): 211622. doi:10.1098/rsos.211622. PMC 8826131. PMID 35154797. S2CID 246652851.
  14. Richard J. Butler; Sterling J. Nesbitt; Alan J. Charig; David J. Gower; Paul M. Barrett (2018). "Mandasuchus tanyauchen, gen. et sp. nov., a pseudosuchian archosaur from the Manda Beds (?Middle Triassic) of Tanzania" (PDF). Journal of Vertebrate Paleontology. 37 (Supplement to No. 6): 96–121. doi:10.1080/02724634.2017.1343728. S2CID 90164051.
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  16. Nesbitt, Sterling J.; Butler, Richard J.; Ezcurra, Martín D.; Barrett, Paul M.; Stocker, Michelle R.; Angielczyk, Kenneth D.; Smith, Roger M. H.; Sidor, Christian A.; Niedźwiedzki, Grzegorz; Sennikov, Andrey G.; Charig, Alan J. (2017). "The earliest bird-line archosaurs and the assembly of the dinosaur body plan" (PDF). Nature. 544 (7651): 484–487. doi:10.1038/nature22037. PMID 28405026. S2CID 9095072.
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  18. Brenen M. Wynd; Brandon R. Peecook; Megan R. Whitney; Christian A. Sidor (2018). "The first occurrence of Cynognathus crateronotus (Cynodontia: Cynognathia) in Tanzania and Zambia, with implications for the age and biostratigraphic correlation of Triassic strata in southern Pangea". Journal of Vertebrate Paleontology. 37 (Supplement to No. 6): 228–239. doi:10.1080/02724634.2017.1421548. S2CID 89972431.
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