Jean-Bernard Caron likes molluscs!

A while back, I discussed the interpretation of the enigmatic Cambrian creature Nectocaris on this space. I just discovered that the same guy (or, well, one of the guys) who described the new Nectocaris fossils as the remains of a primitive cephalopod had also been part of a publication “molluscifying” another enigmatic Cambrian creature. In this somewhat earlier case, Caron et al. (2006) interpret Odontogriphus as a soft-bodied primitive mollusc. Something of a grand-uncle to everything molluscan that lives today. (Unlike Nectocaris, Odontogriphus did, apparently, have a radula.)

Needless to say, this interpretation was immediately contested by another Cambrian expert, Nick Butterfield (Butterfield, 2006). The radula of Odontogriphus (and of the more popular “spiny slug” Wiwaxia) aren’t necessarily true radulae, the serial gills of Odontogriphus need not be the specific kind of gills that molluscs have, etc. (This then triggered a response from Team Mollusc [Caron et al., 2007], but I digress :))

I’m beginning to see a pattern here, something much broader than J-B Caron vs. everyone else. It basically reminds me of the contrast the whole of Wonderful Life (Gould, 1991) was built on. To those who haven’t read the book, one of the central themes of Wonderful Life is the (re-)interpretation of Burgess Shale fossils. Initially, the fossils were all shoehorned into already known groups. Decades later, palaeontologists began to examine them more closely, and found that few of them truly fit into those groups. Out of these surprises grew Stephen Jay Gould’s brave new Cambrian world, the festival of freaks that later dwindled to the pathetic little remnant of its full diversity that populates today’s seas. (We’ll leave the discussion of how right or wrong either view is for another time ;))

Another parallel that comes to mind is the extreme range of interpretations of the earlier Ediacaran organisms, which researchers have flagged as everything from early members of living animal groups to a totally new form of life.

Also, somewhat, the lumper/splitter division that seems to exists in vertebrate palaeontology. There are the “lumpers” who want to group everything vaguely similar into the same taxon, and there are those that want to split everything vaguely unique into its own group. (It should go without saying, but there are also opinions in between. I don’t want you to come away thinking that palaeontology and taxonomy are just armed camps of lumpers and splitters shouting obscenities at each other across a barricade ;))

I get the impression that hardcore lumpers tend to consistently be lumpers and hardcore splitters tend to remain splitters.

Are there just some people who want to connect every new observation to something we’ve already seen? Are there just people with a natural tendency to emphasise the uniqueness of new observations? Or prefer to take the middle ground, as the case may be? Why? And more generally, what makes scientists pick one side – or refuse to pick sides – in controversial issues?

***

References

Butterfield NJ (2006) Hooking some stem-group “worms”: fossil lophotrochozoans in the Burgess Shale. BioEssays 28:1161-1166

Caron J et al. (2006) A soft-bodied mollusc with radula from the Middle Cambrian Burgess Shale. Nature 442:159-163

Caron J et al. (2007) Reply to Butterfield on stem-group “worms”: fossil lophotrochozoans in the Burgess Shale. BioEssays 29:200-202

Gould SJ (1991) Wonderful Life. Penguin.

Mazurek D and Zatoń M (2011) Is Nectocaris pteryx a cephalopod? Lethaia 44:2-4

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