Manda Formation

The Manda Formation (also known as the Manda Beds) is a Middle Triassic geologic formation in Tanzania. It preserves fossils of many terrestrial vertebrates from the Triassic, including some of the earliest archosaurs.[1]

Manda Formation
Stratigraphic range: Anisian
~247–242 Ma
TypeGeological formation
Unit ofCynognathus Assemblage Zone
 Songea 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

Map of the outcropping Manda Formation

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.[2][3] 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).[4]

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

TaxonMemberMaterialNotesImages
Stanocephalosaurus pronus[5]LifuaRemains of a temnospondyl amphibian previously referred either to Parotosaurus or Eryosuchus[6]

Parareptiles

TaxonMemberMaterialNotesImages
Ruhuhuaria reiszi[7]LifuaCAMZM T997, poorly preserved but complete skull and mandibleAn owenettid

Archosauromorphs

TaxonMemberMaterialNotesImages
Asperoris mnyamaLifuaNHMUK PV R36615, incomplete skullA non-crurotarsan archosauriform of uncertain phylogenetic placement
"Stagonosuchus" tanganyikaensis[8]Lifua MemberSAM 11754, right humerusAn indeterminate archosauromorph; possibly a rhynchosaur
Stenaulorhynchus stockleyiLifuaA rhynchosaur
Unnamed[5]LifuaNHMUK PV R36619, incomplete skull and partial postcranial skeletonA non-archosaurian archosauriform
Archosaurs
TaxonMemberMaterialNotesImages
Asilisaurus kongweLifuaA silesaurid dinosauriform
Hypselorhachis mirabilisLifuaNHMUK R16586, a complete dorsal vertebraA sail-backed archosaur possibly belonging to the family Ctenosauriscidae
Mandasuchus tanyauchen[9]Lifua MemberNHMUK R6792, partial mandible and postcranial skeletonsA paracrocodylomorph
Nundasuchus songeaensis[5][10]LifuaNMT RB48, partial skeleton and skullAn archosaur, possibly suchian
Nyasasaurus parringtoni[11]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.[11]
"Pallisteria angustimentum"Lifua MemberNHMUK R36620, partial skull and some postcranial fragmentsA "rauisuchian"; a nomen nudum first identified as a thecodont
Parringtonia gracilisLifuaNHMUK R8646, a mandible, scapula, partial ischium, twelve vertebrae, and five osteodermsAn erpetosuchid
Stagonosuchus nyassicusLifuaGPIT/RE/3831/1-21 and GPIT/RE/3832/1-15, two partial postcranial skeletonsA "rauisuchian"
"Stenaulorhynchus" major[8]Lifua MemberSAM S337, distal half of a left humerusA subjective senior synonym of Stagonosuchus.[11]
Teleocrater rhadinusLifuaNHMUK R6795, vertebrae, limb bones and other elements. Additional material referred from two other individuals.An early avemetatarsalian[12]
"Thecodontosaurus" alophos[11]Lifua MemberSAM-PK-K10654, three neck vertebrae and two rear presacral vertebraeA probable subjective senior synonym of Nyasasaurus, first identified as a sauropodomorph dinosaur.[11]
Unnamed[13]LifuaNearly complete skull and partial skeletonA stem-aetosaur
Dicynodonts
TaxonMemberMaterialNotesImages
Angonisaurus cruickshankiLifuaA kannemeyeriiform
Kannemeyeria simocephalusLifuaA kannemeyeriid kannemeyeriiform
Sangusaurus parringtoniiLifuaA stahleckeriid kannemeyeriiform
?ShansiodonLifuaSkullA shansiodontid kannemeyeriiform
Tetragonias njalilusLifuaA shansiodontid kannemeyeriiform
Cynodonts
TaxonMemberMaterialNotesImages
Aleodon brachyrhamphusLifuaA possible chiniquodontid
Cricodon metabolusLifuaA trirachodontid
Cynognathus crateronotus[14]LifuaA cynognathid
Diademodon tetragonasLifuaA diademodontid
Scalenodon angustifronsLifuaA traversodontid
"Scalenodon" attridgeiLifuaA traversodontid; may fall outside the genus Scalenodon and may be a synonym of "Scalenodon" charigi
"Scalenodon" charigiLifuaA traversodontid; may fall outside the genus Scalenodon
Mandagomphodon hirschoniLifuaA traversodontid; originally classified in the genus Scalenodon; named after the Manda Beds

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.
  2. Charig, A. J. (1957). New Triassic archosaurs from Tanganyika, including Mandasuchus and Teleocrater: Dissertation Abstracts. Cambridge University.
  3. 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.
  4. 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.
  5. 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.
  6. 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
  7. 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.
  8. 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.
  9. 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.
  10. Nesbitt, Sterling J.; Sidor, Christian A.; Angielczyk, Kenneth D.; Smith, Roger M. H.; Tsuji, Linda A. (November 2014). "A new archosaur from the Manda beds (Anisian, Middle Triassic) of southern Tanzania and its implications for character state optimizations at Archosauria and Pseudosuchia". Journal of Vertebrate Paleontology. 34 (6): 1357–1382. doi:10.1080/02724634.2014.859622.
  11. 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.
  12. 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.
  13. Nesbitt, S.J.; Sidor, C.A.; Angielczyk, K.D.; Smith, R.M.; Parker, W. (2012). "Derivation of the aetosaur osteoderm carapace: evidence from a new, exceptionally preserved "stem aetosaur" from the Middle Triassic (Anisian) Manda Beds of southwestern Tanzania". Journal of Vertebrate Paleontology. 32 (Supp. 1): 149. doi:10.1080/02724634.2012.10635175.
  14. 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.
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