Pitinga Formation, Lower Unit (Silurian to of Brazil)

Where: Brazil (1.1° S, 57.8° W: paleocoordinates 64.6° S, 110.5° W)

• coordinate stated in text

• basin-level geographic resolution

When: Lower Unit Member (Pitinga Formation), Llandovery to Llandovery (443.4 - 427.4 Ma)

• These fossil collections have generally been described (e.g. Lange 1972, PBDB ref. 7147) as coming from the Nhamunda Formation. According to Grahn, they are actually from the Pitinga Formation, which is largely coeval and intercalating with the Nhamunda. Age call is based in part on chitinozoan zonation of Grahn (text-figure 2).

• member-level stratigraphic resolution

Environment/lithology: marine; sandstone and siltstone

• See lithology.
• "The lithologies consist of green-grey to dark grey, micaceous, carbonaceous, pyritic and partly sideritic shale with interbedded shaly siltstone. Hematite layers occur at the base. The prevailing depositional environments were probably muddy shoreface and offshore during a rapid transgression. On the northern margin along Trombetas River, the unit is represented by shallow water tempestitic sandstone with interbedded siltstone. These layers yield the shelly fossils."

Primary reference: Y. Grahn. 1992. Revision of Silurian and Devonian strata of Brazil. Palynology 16:35-61 [M. Foote/M. Foote/M. Foote]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 25622: authorized by Michael Foote, entered by Michael Foote on 19.09.2002, edited by Pete Wagner

Creative Commons license: CC BY (attribution)

Taxonomic list

• Taxonomy from Clarke (1899) and in need of revision.
Ostracoda
 Palaeocopida - Bolliidae
Bollia lata1 ostracod
 Palaeocopida - Primitiidae
Primitia minuta1 ostracod
Lophophorata
 Tentaculitida - Tentaculitidae
Strophomenata
 Productida - Strophochonetidae
Rhynchonellata
 Rhynchonellida - Leptocoeliidae
Anabaia paraia
(=Harringtonina)
 Orthida - Heterorthidae
 Orthida - Orthidae
Orthis callactis1 Dalman 1827
subsp. amazonica
Lingulata
 Lingulida - Disciniidae
 Lingulida - Lingulidae
Craniata
 Craniopsida - Craniopsidae
Rostroconchia
  -
? Conocardium sp. Bronn 1835
Bivalvia
 Modiomorphida - Allodesmatidae
 Protobranchia - Ctenodontidae
"Tellinomya pulchella" = Ctenodonta1, "Tellinomya subrecta" = Ctenodonta1
"Tellinomya pulchella" = Ctenodonta1 clam
"Tellinomya subrecta" = Ctenodonta1 clam
 Protobranchia - Nuculanidae
Clidophorus brasilianus1 pointed nut clam
Gastropoda
 Bellerophontida - Plectonotidae
Plectonotus sp. Clarke 1899 snail
 Murchisoniina -
Murchisonioidea indet.2 Koken 1896 snail
Cephalopoda
 Orthocerida - Orthoceratidae
? Orthoceras sp. Breynius 1832
  -
Hexactinellida
  -
Hexactinellida indet.1 Schmidt 1870 glass sponge
spicules
Scyphozoa
 Conulariida - Conulariidae