Also known as Mount Crean (MS5, MS6; RS625-628)

Where: Antarctica (77.9° S, 159.6° E: paleocoordinates 32.1° S, 167.1° E)

• coordinate estimated from map

When: kohni other zone, Aztec Siltstone Formation, Emsian to Emsian (407.6 - 382.7 Ma)

• "It was placed in the late Middle Devonian (Givetian) in the macrovertebrate biostratigraphic zonation for East Gondwana of Young (1996; MAV6), aligning approximately with the varcus conodont zone of the middle Givetian (Young & Turner 2000, fig. 2). Turner (1997) considered the thelodont Turinia antarctica to be of early Givetian age; this taxon identifies the lowest two zones (6a, 6b) in the biostratigraphic scheme for the Aztec sequence first proposed by Young (1988, fig. 5). All actinopterygian material so far identified from the Aztec sequence comes from equivalent horizons at Mount Crean, and also from the slightly higher ‘portalensis’ biozone at Portal Mountain. Young & Long (2005, fig. 12) showed the entire Aztec assemblage (MAV6) confined to the varcus conodont zone, and whilst this is reliable for the phyllolepid placoderms which come from the uppermost Aztec zones, it should be noted that a reliable maximum age constraint for the Aztec sequence is not available. Young & Long (2005) provided evidence that the entire sequence is diachronous from the north to the south. On present evidence, all of the actinopterygian material described below is at least as old as Givetian, and may be older (?Emsian–Eifelian), given that there is no convincing evidence placing an older age limit on the Aztec sequence." (Long et al 2008)

• formation-level stratigraphic resolution

Environment/lithology: marine; siltstone and calcareous shale

Size class: macrofossils

Primary reference: G. C. Young, J. A. Long, and A. Ritchie. 1992. Crossopterygian fishes from the Devonian of Antarctica: systematics, relationships and biogeographic significance. Records of the Australian Museum, Supplement 14:1-77 [G. Lloyd/G. Lloyd/G. Lloyd]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 207077: authorized by Graeme Lloyd, entered by Graeme Lloyd on 19.12.2019, edited by Joseph Flannery-Sutherland

Creative Commons license: CC BY (attribution)