+ Site Statistics
+ Search Articles
+ Subscribe to Site Feeds
EurekaMag Most Shared ContentMost Shared
EurekaMag PDF Full Text ContentPDF Full Text
+ PDF Full Text
Request PDF Full TextRequest PDF Full Text
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter
Follow on LinkedInFollow on LinkedIn

+ Translate

Taphonomy of the south Brazilian Triassic herpetofauna: Fossilization mode and implications for morphological studies

Taphonomy of the south Brazilian Triassic herpetofauna: Fossilization mode and implications for morphological studies

Lethaia 31(4): 335-345

Skulls and limb bones of reptiles from Mid-Triassic rocks in southern Brazil show striking morphological and volumetric differences among specimens from the same taxonomic group; this is caused by early calcite cementation. Petrographic analysis of 40 thin sections of selected fossil bones demonstrates that the main agent of fossilization was precipitation of calcite and minor hematite in the pores of bones during early burial mineralization. The framework of the bones has been broken and replaced by calcite (and hematite), beginning in the spongy inner part of the bone (the cancellous bone) and gradually extending into the compact external layers. Three taphonomic groups of fossil bones are recognized: I - those almost entirely retaining their original structure and shape; II - those whose internal structure is destroyed, but which still have solid outer 'bone surface', and III - those composed of fragments of bone apatite 'floating' in a carbonate matrix. Destruction of the bone structure was caused by the displacive force of calcite crystallization, which typically occurs at shallow burial, during early diagenesis. This process occurs in the vadose zone and requires markedly alternating wet and dry seasons, which indicates a semi-arid paleoclimate for the south Brazilian Mid-Triassic, an inference consistent with other paleoclimatic data. Diagenesis can significantly alter the shape and size of bones and cause considerable morphological variation within the same fossil group, possibly leading to taxonomic misinterpretation.

(PDF emailed within 0-6 h: $19.90)

Accession: 011452169

Download citation: RISBibTeXText

DOI: 10.1111/j.1502-3931.1998.tb00523.x

Related references

Taphonomy of the south-Brazilian Triassic vertebrates. Revista Brasileira de Geocienciassetembro; 30(3): 491-494, 2000

Vertebrate taphonomy of the South Brazilian Triassic rocks. Revista Brasileira de Geociencias 30(1-3, 2000, 2000

Taphonomy of the south Brazilian Triassic paleoherpetofauna: Pattern of death, transport and burial. Palaeogeography Palaeoclimatology Palaeoecology 107(1-2): 179-197, 1994

Silt injection as a mode of fossilization: A Triassic example. Palaios 14(6): 545-554, 1999

Biomolecular and physical taphonomy of angiosperm leaf during early decay; implications for fossilization. Palaios 19(5): 428-440, 2004

Mechanical properties of the chitin-calcium-phosphate clam shrimp carapace (Branchiopoda: Spinicaudata): implications for taphonomy and fossilization. Journal of Crustacean Biology 35(2): 123-131, 2015

Heterogeneous rare earth element REE patterns and concentrations in a fossil bone; implications for the use of REE in vertebrate taphonomy and fossilization history. Geochimica et Cosmochimica Acta 74.10: 2970-2988, 2010

Fossilization (taphonomy). Unknown, 1979

Taphonomy: the process of fossilization.. Cranium. oktober; 122: 65-70, 1995

Current topics on taphonomy and fossilization. Unknown, 2002

Taphonomy and fossilization Tafonomia y fosilizacion. Cuadernos de Geologia Iberica, 23: 1-300, 1997

The patterns of evolution of Early Triassic herpetofauna in Europe and Gondwana: comparison and implications. Russian Journal of Herpetology. June; 12: 301-303 (Supplement), 2005

Taphonomy, the understanding of fossilization processes in paleontology and archeology. Geobios 41(1): 1-3, 2008

Taphonomy of the prosauropod dinosaur Sellosaurus, and its implications for carnivore faunas and feeding habits in the Late Triassic. Palaeogeography, Palaeoclimatology, Palaeoecology 143(1-3): 1-29, 1998

Early and Middle Triassic trends in diversity, evenness, and size of foraminifers on a carbonate platform in south China; implications for tempo and mode of biotic recovery from the end-Permian mass; extinction. Paleobiology 37.3, 2011