Wednesday, 23 February 2011

Kicked by Thunder Thighs

A new sauropod has been found in a Utah site and named Brontomerus mcintoshi. Thunder thighs. Nice. The designation is on the strength of bones from two specimens collected in the 90s from the Hotel Mesa Quarry in Grand County, Utah, dated to about 110 million years old. Its hip bones suggest huge thigh muscles, hence the name. Comparing the bones with those of better-known relatives, it's thought the adults may have been around 14 metres long and weighed six tonnes. The heavy musculature of the upper rear limbs meant the animal could probably have delivered hefty kicks, either for defence or to establish dominance for mating rights. It may also have been able to 'stand up' for short periods, perhaps for browsing. Another suggestion is that the extra strength could have been to power very long legs - not enough material was found to support this idea, though.

A nice find. What really caught my attention, though, was the kicking given to commercial collectors in the article. A large chunk was given over to it. It describes the bones as 'rescued' from the quarry, and in this case I don't think the journalist means saved from the elements. The piece says the site 'has been looted by commercial fossil-hunters' and Dr Taylor, one of the researchers involved, describes the site as vandalised. He says commercial collectors smashed up the bones they didn't want - which seems unlikely to me. They may well have been broken but it's purely speculative to say how, why (if intentional at all) and by whom.

I definitely understand his frustration at not having more of the specimen(s) to study, and of course anyone collecting - privately, commercially or academically - needs to go about it correctly, respecting the site and material and recording helpful information. Seeing bone material used to weigh down a tarpaulin would annoy me, too. Reading a little more about the site's history shows the place 'previously known to private collectors' and that collecting had gone on there for some time. Difficult to see how the research team can feel all proprietorial about it - because they weren't there first and didn't find everything they wanted the site has been 'pillaged'? A bit rich if you ask me.

Friday, 18 February 2011

Roll up! Roll up!

I have a couple of nice enrolled trilobites at home already, but bought this one in Tucson. It's a phacopid from Morocco, near Western Sahara. Think its name is Gravlops. Trilobites had a diverse array of body shapes and ornamentation, but most trilobites could roll up to some extent to protect their soft undersides with their exoskeleton. Some into balls like a hedgehog, some tucking into their broad headshield, some, like the tiny Agnostus, folding flat like a... like a... pastie? Phacops and its close relatives became masters of the ball defence, developing specialised grooves to enable a precise enrollment.

Many trilobites are preserved with a common sort of  bend, their cephalon at a ninety degree angle to their bodies. It's known that many were burrowers and these bent trilobites may have died while poking out of their burrows, head resting on the surface, the rest tucked safely away. What would they have been hiding from? Trilobites were around for about 280 million years, so what they were eating and what was eating them changed a fair bit over that time. To begin with, in the early Cambrian 520 million years ago, they would have had to hide from nautiloids, eurypterids and the star of the Burgess Shale, Anomolocaris. With the rise of the fish in the Devonian, trilobites had something else to worry about. The final curtain, though, was the Great Dying, the extinction event at the end of the Permian, 250 million years ago, when 96% of marine species kicked the bucket. Rolling up into a ball doesn't save you from everything.