Ichnotaxonomy (was 'dino tracks near Syracuse?')

ICZN 1999, Article 23.7.3: A name established for an ichnotaxon does not compete in priority with a name established for an animal (even for the animal that formed, or may have formed, the trace fossil).

i.e. It is COMPLETELY IRRELEVANT whether animal A made footprint B. The names A and B are independent of each other. Thus Grallator and Coelophysis are both valid. One is a footprint - a sedimentary structure made by an animal - the other is an animal.

1. You do not need to know the trackmaker's identity in order to name a track taxon. If you did, we would not be able to name ANY vertebrate track as we do not find dead bodies at the end of a trackway! And you would have to write up each occurence by including a lengthy description, e.g. 'small tridactyl ichnite, with 2, 3, and 4 pads (excluding claw marks) on the inner, middle and outer toes respectively, relatively small angle of divariaction, relatively long projection of the middle toe beyond the 2 outer ones......'. Good grief, that would make any site description a real pain in the (&*^. Why bother to say all that when you can call it "Grallator". Or Fred. Or whatever.

2. Take a look at the skeletal record. Different species, genera, "higher-level taxa" are named on even the slightest of differences. How many times in a description, or character matrix, do you see characters of the hands or feet used? Sure, they can be important. Feet HAVE changed thru time and diff. groups have diff. basic foot structures. But it is certainly not the case that EVERY SINGLE ANIMAL can be differentiated by their feet.

THEREFORE it is ILLOGICAL to expect an ichnospecies to have been made by a single skeletal species. Edward Hitchcock INVENTED the science of ichnology (well, just about) and HE recognised this. In the 1830s. On the other hand, it is ENTIRELY POSSIBLE that if a particular clade's foot structure is conservative and does not change much, that the footprints made by the indiv. spevies/genera will look very similar.

Therefore, an ichnotaxon can be much longer-ranging than a skeletal taxon. (That does NOT make it biostratigraphically useless. You find a footprint that you attribute to a dinosaur, in strata of unknown age, well, you can say "Mesozoic". Sure it's not a high-level stratigraphy but heck, stratigraphy had to start somewhere.)

It is therefore also completely unnecessary to give different names to 2 footprints with identical morphologies that are of differing ages. There was an example on the list a while back of bird tracks from I think Maryland and Wyoming (?), of different ages (by some 15 million years) but essentially IDENTICAL in every way, and people were wanting to give the MD (?) ones a new name ONLY because they are a different age. There is NO NEED and NO JUSTIFICATION for this. It simply means that "birds with a particular foot structure were around for >15 m.y.". Or to put it another way, you have evidence of a long-ranging clade.