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Re: ichnogenera and ichnospecies



In a message dated 95-12-12 16:30:18 EST, NKING.UCS@smtp.usi.edu writes:

>In fact, nomenclature for trace fossils ("ichnofossils") is different 
>from that of body fossils, whether or not you THINK YOU KNOW what the 
>trace-maker was.  ICZN recognizes the categories ichnogenus and 
>ichnospecies having etymological rules that are parallel to genera and 
>species of body fossils.  However, there are no higher taxonomic 
>categories.  
>
>Trace fossils are regarded as a kind of sedimentary structure rather than 
>a biological entity, hence naming them using rules of biological 
>nomenclature really isn't logical.  Nevertheless, since the practice 
>became ingrained (in the late 1800's) before we understood the origin of 
>a number of strange markings (they weren't as obvious as dino 
>footprints), the ICZN has grudgingly accepted the practice.
>
>But no, you cannot use the body fossil name for a trace fossil, no matter 
>how certain you are of its maker.  To paraphrase a recently controversial 
>question:  Were you there to actually see what the trace-maker was?  Then 
>how can you be so certain?  Another advantage to sticking with the 
>ichnological name is that it tells people what you have, in fact, 
>found--whether it is a set of foot bones or just the marking left by that 
>foot as it walked along.  So, if you abandon the ichnofossil name you 
>have lost a bit of information in your attempt at communication.

Herewith my reply to Jim Farlow, who also pointed this out:

"Is this solely because of the impossibility of establishing the identity of
trace-maker and trace-fossil?

Ah--here's the relevant passage:

ICZN Article 23g(iii): "a name established for an ichnotaxon does not compete
in priority with one established for an animal, even for one that may have
formed the ichnotaxon."

It's weirdly worded. That the ichnotaxon "does not compete in priority" with
the animal taxon can be interpreted to mean that the taxonomies are kept
separate, _or_ that priority is simply not applied for ichnotaxa relative to
animal taxa--which would mean that the animal taxon gets the nod in any issue
where the taxa are considered synonymous. Of course, the problem vanishes if
you are confident that ichnotaxa can never be proved synonymous with animal
taxa (not even when you find a trail of footprints leading to a skeleton)."

The relationship between ichnotaxonomy and "normal" taxonomy is not
_completely_ obvious...