Pastos Bons Formation

Pastos Bons Formation
Stratigraphic range: Oxfordian-Kimmeridgian ~161–151 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Geologic map of the Parnaíba Basin with the Jurassic in red
Type	Geological formation
Underlies	Mosquitos Formation
Overlies	Sardinha Formation
Lithology
Primary	Sandstone
Other	Shale
Location
Coordinates	6°06′S 44°42′W / 6.1°S 44.7°W / -6.1; -44.7
Approximate paleocoordinates	2°24′S 12°06′W / 2.4°S 12.1°W / -2.4; -12.1
Region	Maranhão
Country	Brazil
Extent	Parnaíba Basin
Type section
Named for	Pastos Bons
Pastos Bons Formation (Brazil)

The Pastos Bons Formation is a Late Jurassic (Oxfordian to Kimmeridgian) geologic formation of the Parnaíba Basin in Maranhão, northeastern Brazil. The formation forms part of the sag phase of the basin. It overlies the Sardinha Formation and is overlain by the Mosquito Formation.^[1] The fluvial to lacustrine sandstones and shales have provided fossils of a coelacanth fish, Parnaibaia maranhaoensis and a paralligatorid named after the formation, Batrachomimus pastosbonensis.

Fossil content

The following fossils were reported from the formation:^[2]

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.

Crocodylomorphs

Crocodylomorphs of the Pasto Bons Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Batrachomimus[3]	B. pastosbonensis				A paralligatorid neosuchian.

Fish

Fishes of the Pasto Bons Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Lophionotus[4]	L. parnaibensis				A semionotid fish.
Parnaibaia[5]	P. maranhaoensis				A mawsoniid coelacanth.
Quasimodichthys[6]	Q. piauhyensis				A semionotiform fish.

Plants

Plants of the Pasto Bons Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Araucariaceae Indet.	Indeterminate

See also

• Takutu Formation, contemporaneous formation of northern Brazil and Guyana

References

1. De Castro et al., 2016, p.532
2. Pastos Bons Formation at Fossilworks.org
3. Felipe C. Montefeltro; Hans C. E. Larsson; Marco A. G. de França; Max C. Langer (2013). "A new neosuchian with Asian affinities from the Jurassic of northeastern Brazil". Naturwissenschaften. 100 (9): 835–841. Bibcode:2013NW....100..835M. doi:10.1007/s00114-013-1083-9. PMID 23893176. S2CID 11705304.
4. Gallo, V.; de Paiva, H. C. L.; Petra, R.; Brito, P. (2022). "Lophionotus parnaibensis, sp. nov. (Semionotiformes, Semionotidae) in the Upper Jurassic of the Parnaíba Basin, Northeastern Brazil". Journal of Vertebrate Paleontology. 41 (4). e1994983. doi:10.1080/02724634.2021.1994983. S2CID 246164511.
5. Yabumoto, 2007
6. Hanna Carolina Lins de Paiva; Valéria Gallo (2018). "Quasimodichthys gen. nov. (Neopterygii: Semionotiformes): A morphological and ontogenetic study". Journal of South American Earth Sciences. 88: 132–143. Bibcode:2018JSAES..88..132P. doi:10.1016/j.jsames.2018.08.010. S2CID 134986658.

Bibliography

• De Castro, David Lopes; Bezerra, Francisco Hilário; Fuck, Reinhardt Adolfo; Vidotti, Roberta Mary (2016), "Geophysical evidence of pre-sag rifting and post-rifting fault reactivation in the Parnaíba basin, Brazil", Solid Earth, 7 (2): 529–548, Bibcode:2016SolE....7..529L, doi:10.5194/se-7-529-2016, retrieved 2020-07-07
• Montefeltro, F.C.; Larsson, H. C. E.; França, M. A. G.; Langer, M. C. (2013), "A new neosuchian with Asian affinities from the Jurassic of northeastern Brazil", Naturwissenschaften, 100 (9): 835–841, Bibcode:2013NW....100..835M, doi:10.1007/s00114-013-1083-9, PMID 23893176, retrieved 2020-07-07
• Yabumoto, Y (2007), "A New Mesozoic coelacanth from Brazil (Sarcopterygii, Actinistia)", Paleontological Research, 12 (4): 329–343, doi:10.2517/prpsj.12.329