Wikipedia

Sangkarewang Formation

The Sankarewang Formation is an ?Eocene-aged geological formation in Sumatra, Indonesia near Padang. It is among the very few Paleogene fossil deposits from Southeast Asia that preserves a freshwater ecosystem, and contains many of the earliest records of freshwater fish taxa that now predominate the region. Many of the fishes from this formation are well-preserved as articulated skeletons. The fossils of the formation have been known since the 1870s, although they only received significant attention during the 1930s and again starting from the mid-2010s.[1]

Sangkarewang Formation
Stratigraphic range: ?early-mid Eocene
TypeGeological formation
Unit ofOmbilin Basin
UnderliesSawahlunto Formation
OverliesBrani Formation
Lithology
PrimaryShale, sandstone
OtherOil shales
Location
Coordinates0°36′S 100°48′E / 0.6°S 100.8°E / -0.6; 100.8
Approximate paleocoordinates0°30′S 110°18′E / 0.5°S 110.3°E / -0.5; 110.3
RegionWest Sumatra
Country Indonesia
Sangkarewang Formation is located in Indonesia
Sangkarewang Formation
Sangkarewang Formation (Indonesia)

The age for this formation has long been disputed, with suggested ages ranging from the Cretaceous to the Miocene. Although the exact age still remains uncertain, most recent studies have settled on a tentative Paleogene age, with estimates ranging from the Paleocene[2] to the Oligocene. More recently, unpublished palynological data suggests that the overlying Sawahlunto Formation is of middle-late Eocene in age, which would most likely place the Sangkarewang Formation in the early-mid Eocene.[1]

It was deposited within the Ombilin Basin, a small Paleogene-aged rift basin that formed from deformation along the Great Sumatran fault. The Sangkarewang Formation was deposited within a freshwater rift lake that formed in this basin early on, with anoxic bottom waters allowing for the fossilization of the fish skeletons.[3][1] The Sawahlunto Formation, long exploited for its coal seams, was later deposited in the lake on top of the Sangkarewang Formation. During the Oligocene, this gave way to a river delta (the Sawahtambang Formation), and was later flooded by the sea by the Miocene (the Ombilin Formation), before a tectonic uplift raised it above the sea.[3] The formation has been explored for its oil shales.[4]

Paleobiota

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Bony fish

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Partially based on Woodward (1901) & Sanders (1934).[5][6] Sanders (1934) published a comprehensive monograph about the fishes of the formation using a large number of specimens. However, the vast majority of these specimens are now lost, and may have potentially been destroyed during World War II[7], preventing any further study of her specimens.

Genus Species Material Notes Images
aff. Amblypharyngodon aff A. sp. Pharyngeals. A potential carplet.[1]
Bagarius B. gigas Pectoral arch. A goonch catfish.  
"Chirocentrus" "C." polyodon Jaws A fish of uncertain affinities, assigned to the wolf herrings.
Eocyprinus E. sumatranus Articulated skeletons, all lost. A barb.[1]
Hadromos H. sandersae Articulated skeleton. A barb.[1]
Hexasephus H. guentheri Pharyngeals and dentition. A cypriniform.
Musperia M. radiata Fragmentary specimens, another complete specimen likely destroyed A bonytongue.[7]
Notopterus N. primaevus Articulated skeleton. A featherback.  
Ombilinichthys O. yamini Articulated skeleton. A gourami.[8]  
?Osphronemus O. "goramy" Lost articulated skeletons A gourami initially assigned to the modern giant gourami, and likely in the genus Osphronemus; however, the specimens have been lost, hindering further analysis.[8]
'Osteochilus' 'O.' fossilis Lost articulated skeleton A potential labeonine.[1]
Padangia P. amblyostoma (=Thynnichthys amblyostoma) Articulated skeleton. A barb.[9]
Pangasius P. indicus (=Pseudeutropius verbeeki, Brachyspondylus saropteryx) Articulated skeleton. A shark catfish.  
Pauciuncus P. bussyi (=Puntius bussyi) Articulated skeletons A potential smiliogastrine.[1]
Protosyngnathus P. sumatrensis (=Aulorhynchus sumatrensis) Articulated skeleton. A pipefish-like syngnathiform.[10]
'Rasbora' 'R.' antiqua Lost articulated skeletons A danionin.
'R.' mohri
Sangkarewangia S. sumatranus Articulated skeleton. A barb.[1]
Scleropages S. sp. Fragmentary remains. An arowana.  
Sundabarbus S. megacephalus (=Barbus megacephalus) Articulated skeleton. A barb.[9]
Toxotes T. beauforti Articulated skeleton. An archerfish, closely resembling modern species.[6][11]  

Birds

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Genus Species Material Notes Images
Protoplotus P. beauforti Articulated skeleton with gastroliths. A protoplotid suliform, related to cormorants and darters.[12][13]

References

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  1. ^ a b c d e f g h i Murray, Alison M. (2020-01-02). "Early Cenozoic Cyprinoids (Ostariophysi: Cypriniformes: Cyprinidae and Danionidae) from Sumatra, Indonesia". Journal of Vertebrate Paleontology. 40 (1): e1762627. doi:10.1080/02724634.2020.1762627. ISSN 0272-4634.
  2. ^ "PBDB Collection". paleobiodb.org. Retrieved 2024-09-25.
  3. ^ a b Whateley, M. K. G.; Jordan, G. R. (1989). "Fan-delta-lacustrine sedimentation and coal development in the Tertiary Ombilin Basin, W Sumatra, Indonesia". Geological Society, London, Special Publications. 41 (1): 317–332. doi:10.1144/GSL.SP.1989.041.01.22. ISSN 0305-8719.
  4. ^ Fatimah; Ward, Colin R. (2009-01-31). "Mineralogy and organic petrology of oil shales in the Sangkarewang Formation, Ombilin Basin, West Sumatra, Indonesia". International Journal of Coal Geology. CSCOP-TSOP-ICCP 2007 Selected papers from the 2007 joint meeting of CSCOP-TSOP-ICCP: Unconventional petroleum systems & advances in organic petrology and geochemistry. 77 (3): 424–435. doi:10.1016/j.coal.2008.04.005. ISSN 0166-5162.
  5. ^ Geology, British Museum (Natural History) Department of; Woodward, Arthur Smith (1901). Catalogue of the Fossil Fishes in the British Museum (Natural History): Actinopterygian Teleostomi of the suborders Isospondyli (in part), Ostariophysi, Apodes, Percesoces, Hemibranchii, Acanthopterygii, and Anacanthini. order of the Trustees.
  6. ^ a b Sanders, Margaretha (1934). Die fossilen Fische der alttertiären Süsswasserablagerungen aus Mittel-Sumatra (in German). Mouton.
  7. ^ a b Taverne, Louis (2009). "New insights on the osteology and taxonomy of the osteoglossid fishes phareodus, brychaetus and musperia teleostei, osteoglossomorpha". Bulletin de l'Institut Royal des Sciences Naturelles de Belgique - Bulletin van het Koninklijk Belgisch Instituut voor Natuurwetenschappen. 79: 176–190.
  8. ^ a b Murray, A M.; Zaim, Y.; Rizal, Y.; Aswan, Y.; Gunnell, G F.; Ciochon, R L. (2015-03-04). "A fossil gourami (Teleostei, Anabantoidei) from probable Eocene deposits of the Ombilin Basin, Sumatra, Indonesia". Journal of Vertebrate Paleontology. 35 (2): e906444. doi:10.1080/02724634.2014.906444. ISSN 0272-4634.
  9. ^ a b Murray, Alison M. (2019-09-02). "Redescription of Barbus megacephalus Günther, 1876 and Thynnichthys amblyostoma von der Marck, 1876 (Cypriniformes: Cyprinidae) from probable Eocene deposits of Southeast Asia, and an assessment of their taxonomic positions". Journal of Systematic Palaeontology. 17 (17): 1433–1455. doi:10.1080/14772019.2018.1533897. ISSN 1477-2019.
  10. ^ Murray, Alison M. (2022-12-31). "Re-description and phylogenetic relationships of † Protosyngnathus sumatrensis (Teleostei: Syngnathoidei), a freshwater pipefish from the Eocene of Sumatra, Indonesia". Journal of Systematic Palaeontology. 20 (1): 1–16. doi:10.1080/14772019.2022.2113832. ISSN 1477-2019.
  11. ^ "A REVIEW OF THE ARCHERFISHES (FAMILY TOXOTIDAE) | Western Australian Museum". museum.wa.gov.au. Retrieved 2024-09-25.
  12. ^ VAN TETS, G.F; RICH, P. V.; RINI MARINO-HADIWARDOYO, H. (1989). "A reapraisal of Protoplotus beauforti from the Early Ttertiary of Sumatra and the basis of a new Pelecaniform familynimy". A reapraisal of Protoplotus beauforti from the Early Ttertiary of Sumatra and the basis of a new Pelecaniform familynimy (5): 57–75.
  13. ^ Mayr, Gerald (2022), Mayr, Gerald (ed.), "Phaethontiformes and Aequornithes: The Aquatic and Semi-aquatic Neaovian Taxa", Paleogene Fossil Birds, Cham: Springer International Publishing, pp. 117–152, doi:10.1007/978-3-030-87645-6_7, ISBN 978-3-030-87645-6, retrieved 2024-09-25
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