Usili Basal Conglomerate (Permian of Tanzania)

Where: Ruvuma, Tanzania (10.4° S, 35.1° E: paleocoordinates 55.2° S, 15.1° E)

• coordinate stated in text

• outcrop-level geographic resolution

When: Cistecephalus other zone, Usili Formation (Songea Group), Wuchiapingian (259.9 - 254.2 Ma)

• member-level stratigraphic resolution

Environment/lithology: terrestrial; lithified conglomerate

• The basal intraformational conglomerates comprise three fining-upward sequences comprising erosively based lenticular bodies of clast-supported conglomerate overlain by gritstone and coarse to fine sandstone beds. The clasts immediately overlying the erosion surface are predominantly cobble-sized spherical and oblate calcareous nodules, the latter with distinct stromatolitic textures. These conglomerates are clearly derived from erosion of the underlying Ruhuhu Formation. They are overlain by a more extensive tabular beds of matrix-supported clay pebble conglomerate with abundant haematite-encrusted fossil bones and gritstone beds with fine sandstone matrix containing some pebble-sized extrabasinal quartzite clasts. The uppermost levels of the second sequence contain numerous silicified tree trunks that are much more resistant to weathering than the host matrix and can be used as a local marker horizon.

Size class: macrofossils

Collection methods: surface (float), surface (in situ),

• National Museum of Tanzania

Primary reference: C. A. Sidor, K. D. Angielczyk, D. M. Weide, R. M. H. Smith, S. J. Nesbitt and L. A. Tsuji. 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 [C. Sidor/C. Sidor]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 135700: authorized by Chris Sidor, entered by Chris Sidor on 03.11.2012

Creative Commons license: CC BY (attribution)

Taxonomic list

 Temnospondyli -
Peltobatrachus pustulatus Panchen 1959 tetrapod
 Therapsida - Burnetiidae
Burnetiidae indet. Broom 1923 therapsid
NMT RB4, partial skull roof including dorsal margin of orbits and parietal foramen. NMT RB36, fragmentary right dorsal margin of orbit.
 Therapsida - Kingoriidae
Dicynodontoides nowacki von Huene 1942 dicynodont
 Therapsida -
Dicynodon huenei Haughton 1932 dicynodont
Endothiodon sp. Owen 1876 dicynodont
 Therapsida - Cryptodontidae
Rhachiocephalus magnus Owen 1876 therapsid