Monday, January 19, 2009

Name Game Revisited

I am fascinated by the process through which fossils, including tracks and other traces, are named and, often, renamed. I wrote on this previously in a couple of posts (What's in a Name? Part Un, and What's in a Name? Part Deux), but, as a paleontology newbie, I keep encountering other aspects of the process that intrigue and challenge me. Forgive me in advance if I’m wrong about something below (a gentle comment to that effect is welcome).

Duplicate Names Forbidden

Raymond C. Moore and his colleagues in their classic volume entitled Invertebrate Fossils (1952) described some of the basic rules that apply to the naming of fossils. Among those rules is the following:

“An important requisite of the scientific names of animals, whether of genera or of species, is that none shall duplicate another. Obviously, confusion and error are unavoidable if identical names may refer to different kinds of animals. . . . Homonyms (identical names applied to different things) are not allowed, and if, as has happened frequently, such names for genera or species appear in print, the later-published name is invalid.”

Duplicate names are forbidden – supremely logical.

A series of recent posts in a great blog – Dinochick Blogs – illustrates this rule at work. In this instance, at issue is the name to be applied to the dinosaur that for over 100 years was known as Diceratops. Seems that an inhabitant of the insect world already had legitimate claim to that name – the name was “preoccupied” (wonderful use of the word). So, apply the rule and come up with a new name.

Two researchers, independent of each other, each recently applied a new name to the Diceratops: (1) Diceratus – this name, derived from Greek, means “two-horned” or (2) Nedoceratops – the apparent derivation of the name is from “nedo,” a Russian prefix meaning “insufficient” or “incomplete” or “not quite” (well, that’s what my reading on the Web turned up for “nedo”), and from “ceratops,” from Greek for “horned face.” Nedoceratops was proposed in a publication that came out before Diceratus. Because prior publication prevails, Nedoceratops it is.

Logical rule, but, in this case, not a pleasing result for many. There are those who find Nedoceratops an insulting name for the dinosaur. Though one may acknowledge that, over all of these years, this dinosaur has been identified on the basis of a single specimen (not unprecedented), the name earns low marks in the politic or tact category. It’s almost as though the prevailing researcher (reportedly an entomologist) deliberately snubbed the dinosaur itself. A variant of paleontological one-upsmanship (see earlier post) at work? “I picked an irritating name because I can.” I don’t know, but the thought occurred to me.

Ichnotaxon, Ichnogenus

There’s another bit of impressive logic in the naming process. After a recent visit to a collection of dinosaur tracks outside of Hartford, Connecticut (Dinosaur State Park in Rocky Hill), I registered the facts, without really thinking about them, that the tracks had a genus name, Eubrontes, but no bones had been found to identify the animal that might have made them.

The speculation is that the tracks recorded passages of a kind of dinosaur similar to the carnivorous Dilophosaurus, whose fossilized remains have been found in Arizona.

Later, in a moment of mental clarity (rare for me, though I don’t think this quite qualifies as an epiphany), I saw the compelling logic of naming tracks or other “trace fossils” (see below) separately from the animal making them. I know this must fall into the “so what” category for those who have lived paleontology. What follows is this neophyte’s take on it.

A track or group of similar tracks may well be the sum of what we have; and, there is no certainty about what made those tracks. So, the tracks, independent of their creator, may be named. After all, we want to be able to talk about the tracks and, at a minimum, a name certainly simplifies things. Such a name is being applied to an “ichnotaxon,” a classification unit “based on the fossilized work of an organism, including fossilized trails, tracks or burrows (trace fossils) made by an animal.” (International Code of Zoological Nomenclature, see Glossary) In the case of the tracks at Dinosaur State Park, Eubrontes is the “ichnogenus” for these tracks, a name that lives independently of the still unknown creatures that made them.

It doesn’t take much to impress me, I guess.


  1. A track or group of similar tracks may well be the sum of what we have; and, there is no certainty about what made those tracks. So, the tracks, independent of their creator, may be named.

    More to the point, many different kinds of organism can make identical traces. This is perhaps easiest to envision with dinosaur tracks, like the ones you mentioned in Connecticut -- there are many genera and species of theropod known from the time in which the tracks were made, and all had essentially identical feet. So lacking a dead body at the end of a trackway, it's impossible to tell which one (if any -- there's always the possibility that undiscovered species made them, too!) made the tracks. Hence, ichnotaxa are divorced from taxa. In one instance that I know of from the invert world, a trace fossil usually attributed to some sort of invertebrate animal has also been discovered to be made by a plant!

  2. Thanks for Jerry D. Harris' comment -- helps to deepen my understand of this aspect of the naming process.


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