informe

[rpmelcho@xxxxxxxxxxxx (Ricardo Nestor Melchor)]

Report
Workshop Ichnofacies and Ichnotaxonomy of the Terrestrial Permian
March 8 - 11, 1997 (Germany)

Sponsored by the Deutsche Forschungsgemeinschaft and Kultusministerium Land 
Sachsen-Anhalt and convened by Professor Hartmut Haubold (Martin-Luther 
University, Halle/Saale, Germany) a workshop to discuss the current problems 
and future of the tetrapod ichnotaxonomy and ichnofacies of the continental 
Permian was recently hold in central Germany. Fifteen selected researchers from
the field of vertebrate and invertebrate ichnology attended the meeting. The 
program was very intensive and included oral presentations, visits to museum 
collections of tetrapod footprints and reconnaissance of outcrops/quarries of 
classical localities of the German continental Permian. 
The activities started in the small town of Nierstein (near Frankfurt), 
continued in Rotenburg, Cornberg, Tambach, and Gotha, to finish in Halle 
(Saale). Most oral sessions were preceded for an introductory speech by the 
convenor (H. Haubold), which always stemmed from its present understanding of 
the nomenclatural problems of some Permian footprint ichnotaxa (Haubold, 1996).
G. Gand (France) talk about the French Permian footprints and its comparison 
with other European ichnofaunas. An overview of the characteristics and 
composition of the large Early Permian tracksites of New Mexico presented by A.
 Hunt (USA) and H. Haubold (Germany) was followed by a reassessment of the rich
 Permian "Collio" ichnofauna of Italy by S. Conti and others (Italy). C. Meyer 
(Switzerland) described a new (and expensive) method of high resolution 
mapping of tracksites.
A. Hunt and others reported on the recent discovery of a Permo-Carboniferous 
tetrapod tracksite in Nova Scotia (Canada), where they found probable evidence 
of gregarious behaviour in tetrapods. A further elaboration on the interplay 
between anatomical input and extramorphological (i.e., non-anatomical) 
deformation of footprints was presented by C. Karl (Germany). A. Seilacher 
from Germany (the pioneer of modern ichnology), underlined some aspects of the 
concept of undertrack applied to vertebrate footprints and the need for studies
 on the mechanics of track formation to understand them. Different topics on 
aeolian tetrapod ichnofaunas were addressed by M. Lockley (USA) and P. McKeever
 (Northern Ireland) & H. Haubold. Lockley highlighted the principles to 
recognise ichnofacies (recurrent associations of particular track types in 
like sedimentary facies) applied to the Laoporus and related ichnofacies. 
McKeever & Haubold used the example of the Scottish Permian ichnofauna to 
remark the sedimentological influences on the previous nomenclature of tracks 
and trackways. Late in the second evening of the workshop we enjoyed the 
detailed description and interpretation of a Triassic tracksite in Lesotho 
(South Africa) by P. Ellenberger (France). 
In front of spectacular large mudcracked and trampled blocks of the Tambach 
Sandstone -both at the quarries and in the Museum der Natur (Gotha)- T. Martens
 (Germany) summarised the ichnofossil and body fossil content of that unit. 
>From the point of view of invertebrate ichnology R. Bromley (Denmark) suggested
 probable ichnotaxobases for tetrapod trace fossils. R. Melchor (Argentina) 
described the composition and affinities of the only two known Permian 
ichnofaunas from Argentina, which further suggest a fairly similar Permian 
terrestrial fauna in the Pangaea Supercontinent. The presentations concluded 
with a re-evaluation of the ichnogenus Pachypes from the Val Gardena Sandstone 
(Italy) by the Italian crew (S. Conti and others).
The last half day was dedicated to discuss the most useful ichnotaxobases in 
tetrapod ichnology and the recommended  procedures for an appropriate 
documentation of tetrapod ichnofaunas. It was agreed that an ichnotaxa must be 
based on morphological characteristics of the track/trackway (after "filtering"
 the noise produced by extramorphological deformations and using a large sample
 size). Furthermore, any description of ichnofaunas should include detailed 
measurements as well as documentation of the sedimentological and 
stratigraphical context of the tracks. The urgency for a deep taxonomic 
revision of most tetrapod Permian ichnotaxa at the light of the present 
consensus was very clear for everybody at the end of the workshop. Finally, if 
these guidelines are followed there are good perspectives for using the 
tetrapod track record in evolutionary studies, icnostratigraphy and 
paleoecology.
The abstracts of the contributions presented during the workshop will be 
submited for publication in Ichnos, and the complete papers will appear late
 this year in the Hallesches Jahrb. Geowiss. (Halle, Germany). Finally, I would 
like to congratulate Professor Harmut Haubold for your initiative to convene this
 successful workshop and for the excellent organisation.

Haubold, H. (1996) Ichnotaxonomie und Klassifikation von Tetrapodenfährten 
aus dem Perm. Hallesches Jahrb. Geowiss., B18:23-88. Halle/Saale.


Ricardo Nestor Melchor
Universidad Nacional de La Pampa, Argentina.
e-mail: rpmelcho@criba.edu.ar