Trilobite (Richard Fortey, 2000)

ISBN 0-00-257012-2

When I read the introduction to one of Fortey’s earlier books, Hidden Landscape, I immediately realised that here was someone who truly understands how it feels to hammer open a rock and discover some treasure within. However, the introductory chapter of Trilobite , which involves an over-extended parable about some Thomas Hardy character, exceeded some kind of threshold in my mind and became, simply, florid. Fortunately, the introduction is soon over and we jump into some very lightly technical details about the beasts themselves: a field in which Fortey is, justly, considered pre-eminent.

“So in just eight technical terms – cephalon, thorax, pygidium, segment, axis, pleura, glabella, eyes – it is possible to begin to embrace the form of these strange animals. To be able to name the parts introduces a certain familiarity. Further, to be competent to recognise the glabella for what it is means that it does not take long to see that one trilobite has a glabella which is quite different from that of another. With language comes discrimination.” – p. 29

Three of the early chapters are organised along morphological lines – Shells, Legs, and Crystal Eyes – each describing important parts of the creatures’ anatomy. It is in the legs chapter, perhaps appropriately, that Fortey really hits his straps with a ‘parade’ of common trilobites, lasting a few pages, from the most ancient to the last of their kind. Each is summed up in a few (too few, for me) sentences, sketching the history of their discovery and a quirky description, of sorts. To give you a taste of what you’re in for, here’s Olenellus:

“The widest part of the animal is at the head end where there are prominent spines at either corner, behind which the body tapers gradually backwards along a thorax comprising many, rather flat segments with prominently spiny tips. … Somehow this looks like a primitive trilobite. It has not yet developed the sutures crossing the headshield that helped its relatives during molting.” – pp. 69-70

Okay, yes, we all know about moths and their acute “sense of smell” (actually, I think they may only be receptive to pheromones; not to smells in general), but even moths have eyes - presumably to avoid bumping into things. There is zero likelihood of a world ruled by, say, smell because – moths notwithstanding – it just isn’t a very useful sense. There is a relationship between wavelength and spatial resolution - which is why we need electrons to probe the targets in our highest resolution microscopes and, not incidentally, why photons provide more information than enormous organic molecules ever can. In the immortal words of Mr. Scott, “You canna break the laws of physics.”

I could prattle on about this, but the reader would be better served by any book about optics, or even an introductory book about telescopes.

The eyes chapter begins with the brief exposition of a highly unlikely notion – some bizarre spin-off of Gould’s “re-played tape” nonsense – to the effect that, but for historical accident, the sense of sight might not have evolved: “the inevitability of vision is … uncertain” (p. 79). I suspect that Fortey may now regret that comment; at least I do hope so. Bacteria, ‘protists’ and plants all respond to light in some way. Ernst Mayr (What Evolution Is, see p. 113 for example) claims that separate animal clades independently evolved vision 40 times. I wouldn't know about 40 times, but it has certainly been more than a few, notwithstanding the common involvement of the same regulatory gene, Pax-6 and its homologues, in most cases. Quite clearly, vagile animals were always “determined” to see, and nothing was ever going to stop them. Since eyes are expensive to maintain (note how quickly they are lost in those creatures which blunder into deep caves) their independent development in almost all vagile clades cannot be coincidence. Fortunately one has to endure only a page of this indulgence before the author is back among the fields he knows – Hox genes, in this particular instance.

Next appears a rather exotic chapter, Exploding Trilobites, dealing ostensibly with the Cambrian explosion but in actuality with several of the personalities involved in the debate – Gould, the McMenamins … – and includes his now, surely, infamous denunciation of Simon Conway Morris (read more). Disappointingly, there is only a passing reference to the Ediacaran biota, which struck me as rather strange since I’d expect this topic to be of acute relevance to any discussion on the origins of metazoans, and particularly trilobites.

The second half of the book, which I will skip over much more briefly, provides a quirky though fascinating insight into some of the actual daily work of a researcher like Fortey; an anthropic but useful discussion of stratigraphy and, unusually in a book like this, extinction. This is followed up by a rare and interesting look at the difficulties of paleogeography in a chapter called Possible Worlds. Finally, oddly cheek-by-jowl in the penultimate chapter, we are treated to a discussion of ontogeny – how little trilobites grew up into big trilobites – and a chronologically arranged review of trilobite evolution.

On balance, I have to admit to some disappointment though. Having read 250-odd pages, ostensibly all about trilobites, by one of the world’s foremost authorities on the subject, I feel no better equipped to tackle the professional literature (e.g. the updated Treatise, not to mention many of Fortey’s own papers) than when I started. I guess I just didn't learn as much as I'd have expected to.

Recommendation: Eccentric, but highly readable.

Look and Feel: Hardback; good quality paper with high resolution b&w photographs on the pages and some b&w plates; indexed. Authoritative, and with the weight and feel of a good text book, but by no means written like one.

(Read more about trilobites.)

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