Hello and welcome one and all to a new wordpress blog!
Those of you who have arrived here from my personal blog at www.benjamindbrooks.co.uk are especially welcome, though if you were looking for more of the same eccentric subjects and idiosyncratic rants, you are likely to be rather disappointed!
‘The Research Notes…’ (this blog) is a place for me to attempt some (ostensibly open-access) science after having graduated from Southampton University last year. The reasons or having it are twofold, one selfless, one selfish.
Firstly and selflessly, if I am going to do Science, I want it to be Open Access fo the simple reason that I believe in the disemination of knowledge to as many people as can get it, for free as far as is possible. Secondly and selfishly, as I am no longer attached to an institution as a student or researcher, and have no advisor to chase me up on things… posting the work (slow as it will necessarily be as it is presently an avocation) will allow anyone to call me out on not doing anything for a while, and so hopefully spur me to do more!
The First Project! Ichthyosaur Specimen LYMPH 2006-72
So then, on to the first project I’m going to be undertaking here on ‘The Research notes…’. The description of an Ichthyosaur specimen on public display at Lyme Regis Museum.
This is a suitably fascinating project to start with (as you’ll see) with but equally it’s a little daunting to someone with no previous descriptive experience – as a ‘generalist’ Geologist by training and a Palaeontologist by interest, I haven’t picked up as many of the requisite skills as I would like, but hopefully this will help change that.
The first thing to do then is to upload a couple of the photographs I have of the specimen to give a general impression of the task ahead, so here you go…
Photo 1, An overview photograph of LYMPH 2006-72
this shot (Copyright: Chris Andrew - he has a better camera than me!) gives an excellent impression of how well preserved the intestinal contents are, you can almost follow the intestine as it wends its way through the body.
this shows one of the interesting features of taphonomy, the specimen's neural spines have "rolled off" in a single block, remaining together even though not articulated with the vertebrae.
What have my researches taught me so far?
Sadly the most useful extremities of the animal are missing (Tip of snout and fore-paddles, loss of rear paddles and most of the tail including the tail bend.) which makes identication somewhat more tentative, but I’ve got to work with what there is¹. (Note; all diagnostic features/tests are taken from McGowan and Motani, 2003).
A fair estimate of the missing jaw section can be made from the tapering of the mandible and dentary (lower and upper jaw-bones respectively) and it seems to me that an extra 15 cm of jaw is justifiable, this gives a Snout length (SL) of approx 28 cm and a Jaw length (JL) of approx 43 cm.
These two measurements produce a Snout ratio (SL/JL) of 0.65
The Orbit diameter (OD) of the animal can be easily measured to 8 cm as it’s fairly intact (N.B.: orbit = eye socket opening)
This coupled with the Jaw length produce an Orbit ratio (OD/JL) of 0.18
These two skull based ratios alone knock out one of the Ichthyosaur species² (Ichthyosaurus breviceps) as the Snout ratio is far too large, and the Orbit ratio far too small!
I also see no evidence (in the photgraphs I’m using) of waisted teeth in the jaw, which knocks I. intermedius out as well.
Then we move on to other factors to determine between I. conybeari and I. communis. The major features normally used here are the Pre-sacral and Pre-flexural vertebrae counts, however as this specimen has neither an intact Ilium (The thigh bone in you or I, used to identify the Pre-Post Sacral divide) and no tailbend (for the Pre-Post flexural divide) these features cannot be used.
The number of front paddle digits on this specimen is 6, the maximum for I. conybeari and minimum for Dorset specimens of I. communis so again this feature isn’t much help. We can however use the presence or absence of notching on the phalanges (digit bones) of the forelimb. in what little of the front paddles is evident, there are no notched phalanges which is consistent with this being a specimen of I. communis. The orbital ratio also helps as it is closer to the upper bound for I. communis (<0.26) than it is to the upper bound for I. conybeari (<0.28).
Anyway, that’s all for now, probably not going to get much if any more done before April (work commitments etc.) but any comments on this post are most welcome! Especially as it’s my first try at this open notebook thing, any tips, suggestions and such. Or corrections for that matter…. if I’ve said/done something stupid please call me on it.
FOOTNOTES
¹ As I’m in Yorkshire at the moment on a Museum Internship I’m working solely from photo’s and making measurements in a rather awkward fashion with CorelDRAW, so these measurements may change – slightly – when I return to Devon next month!
² The more astute observer will notice I don’t explain why I think it belongs to the Genus Ichthyosaurus sp. – Simply put because I cannot prove it using the photographs I have at my disposal presently. But rest assured I’ll remedy this with some close personal inspection of the specimen soon! Apologies for the cop-out 
REFERENCES
McGowan, C., Motani, R. 2003, Handbook of Paleoherpetology, Part 8. Ichthyopterygia. Verlag Dr Friedrich Pfeil, München, 175 pp.
