New Lootsberg Pass, Tweefontein Farm (Triassic of South Africa)

Where: Eastern Cape, South Africa (31.8° S, 24.9° E: paleocoordinates 64.6° S, 24.3° W)

• coordinate stated in text

• small collection-level geographic resolution

When: Lystrosaurus other zone, Palingkloof Member (Balfour Formation), Induan (252.2 - 251.2 Ma)

• "The type locality lies near the top of the Paalingkloof Member of the Balfour Formation of the Beaufort Group, some 36 m above the Permian/Triassic boundary. Biostratigraphically, it falls in the lowermost Lystrosaurus Assemblage Zone (Groenewald and Kitching 1995) and is part of the Lootsbergian land vertebrate faunachron of Lucas (1998)."

• bed-level stratigraphic resolution

Environment/lithology: dry floodplain; massive, paleosol/pedogenic, nodular, brown, red siltstone and conglomeratic sandstone

• "The holotype of Progalesaurus was discovered within a nodule protruding from a small outcrop of reddish brown massive siltstone. Detailed logging of the sedimentary sequence above and below the fossil locality shows several similar nodular horizons interbedded with tabular greenish grey fine-grained sandstone bodies. These mudrocks are interpreted as proximal floodplain deposits that mainly accumulated from episodic flooding of rivers on a semi-arid alluvial plain. The nodules are composed of micrite and interpreted to be of pedogenic origin formed in the B horizon of an arid zone calcic palaeosol. Preferential micritization around buried bone began with bacterial decay that produced a reduction halo around the bones some 0.5 m below the floodplain surface. Later, microcrystalline calcium carbonate was precipitated from groundwater within the reduction envelope and onto the bone surface. The uncompressed state of the skull attests to the early lithi®cation of the calcareous nodule, before the surrounding mud was fully compacted.

•Associated sandstone bodies are up to 4 m thick and extend laterally for 1-2 km. They are predominantly horizontally laminated and contain conglomeratic lenses made up of mudrock pebbles, pedogenic nodules and fragments of bone. These are interpreted as the in-channel deposits of ephemeral, low sinuosity rivers flowing in a general northerly direction across a semi-arid, low gradient alluvial plain."

Size class: macrofossils

Collected by R. Smith in 1998

Collection methods: mechanical,

Primary reference: C. A. Sidor and R. M. H. Smith. 2004. A new galesaurid (Therapsida: Cyndontia) from the Lower Triassic of South Africa. Palaeontology 47:535-556 [R. Butler/R. Butler]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 98601: authorized by Richard Butler, entered by Richard Butler on 14.10.2010

Creative Commons license: CC BY (attribution)

Taxonomic list

Show authors, comments, and common names
Osteichthyes
 Therapsida - Galesauridae
Progalesaurus lootbergensis n. gen. n. sp.
Progalesaurus lootbergensis n. gen. n. sp. Sidor and Smith 2004 cynodont
SAM-PK-K9954, nearly complete skull and postcranial fragments