Buzz Off! Can’t You See I’m Up to My Ears in the Organic Chemistry of El Sidrón’s Dental Calculus???

Hmmm. I’ve been struggling with Stephen Bradley’s comments on my recent post about Neanderthal oral hygiene at El Sidrón. Throughout he has maintained that the most likely source for the chemical constituents revealed by sophisticated mass spectrometry is wood smoke and cooked food. I have tried to suggest alternative natural sources of some of the compounds that he and his co-authors have identified.
     I would be dead in the water after his protracted comments on my earlier efforts were it not for my determination both to overcome my substantial ignorance of organic chemistry and to extend my argument beyond Stephen’s assertions and, indeed, his conclusions. I’m having some success, I think. Take, for example, his insistence that alkenes and alkanes are plant waxes: 

The thermal desorption-GC-MS (TIC) (Fig. 1 inset) is dominated by a series of n-alkanes (carbon numbers C22 to C35), suggesting a higher plant source (Eglinton et al. 1962), most probably derived from plant waxes in the original food consumed.

I’ll ask Stephen or some other organic chemist to adjudicate whether or not I’ve discovered another natural source of these chemicals–insects. Here is a snippet regarding the Dufour gland of a wasp, Habrobracon hebetor (Say) (Hymenoptera: Braconidae). 

The hydrocarbons consist of a homologous series of n-alkanes (n-C21 to n-C31), a trace amount of 3-methyl C23, a homologous series of internally methyl-branched alkanes (11-methyl C23 to 13-methyl C35), one dimethylalkane (13,17-dimethyl C33), a homologous series of monoenes (C(25:1) to C(37:1)) with the double bonds located at Delta9, Delta13 and Delta15 for alkenes of carbon number 25 to 31 and at Delta13 and Delta15 for carbon numbers 33 to 37 and three homologous dienes in very low amounts with carbon numbers of 31, 32, and 33. [emphasis added]*

I realize that eating insects isn’t as sexy as eating cooked plants, specially not wasps. But it’s not just wasps. A quick check suggests that hydrocarbons of all kinds are naturally occurring substances in insects. And it wouldn’t be the first time that a primate was ‘caught’ eating insects. I’ve eaten crickets many times at sushi bars.
     I don’t think I’ll continue in this vein, trying to ferret out alternatives to Hardy et al.’s inferences. At this point I’d just like to chill on my veranda with a cold one.
     But not quite yet. This business with the El Sidrón Neanderthals’ dental calculus has made me think about the assumptions that Stephen Bradley owned up to–that as far as he knows the Neanderthals made fires and cooked food and did numerous other things that you and I might do. I think otherwise.

     I don’t know which is worse: me, having lived with the Middle Palaeolithic archaeological record for going-on 30 years and spending all my time trying to pierce the inferential balloons that my colleagues set free to ascend to the scholarly firmament, or earnest peers like Stephen Buckley having taken breath from those same balloons as a matter of course in their intellectual upbringing, spending all their time inadvertently adding to the cloud of colourful spheres floating above our heads. Whadda you think? I know what I think. I think this calls for me to touch on a subject near and dear to my heart in the near future–the context of discovery versus the context of justification (or verification). I’ve often been accused of being ‘unscientific’ because I start from the assumption that the Neanderthals were dummkopfs. So, stay tuned.

Arch Insect Biochem Physiol. 2003 Nov;54(3):95-109. Novel diterpenoids and hydrocarbons in the Dufour gland of the ectoparasitoid Habrobracon hebetor (Say) (Hymenoptera: Braconidae). Howard RW, Baker JE, Morgan ED.

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