Category Archives: Fossils

Palaeontology Journal Club

Hi everyone,

Just a quick note to let people know that the Palaeontology Journal Club will be starting next Tuesday (23rd Nov.) at 5pm in Jabez Clegg. Each week we’ll be picking a new journal article, and meeting in the pub on the Tuesday to discuss it in a very informal setting. Students from any of the life sciences degrees are welcome to attend.

***as an added incentive, we’re even offering to buy the first round in***

This week’s paper is about ancient DNA. Researchers in New Zealand have tracked the decay rate of DNA in radiocarbon dated fossils of the Moa (an extinct giant ratite). They have found that, even under optimal burial conditions, DNA is unlikely to survive beyond 6-7 million years. Looks like InGen has been lying to us all these years….

http://rspb.royalsocietypublishing.org/content/early/2012/10/05/rspb.2012.1745.abstract

Charlotte

 

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Filed under Dinosaurs, Evolution, Fossils, Uncategorized

ODD POLLINATORS

Insects and plants are intimately linked in terms of their ecology and evolution. Insects and vascular plants both first appear in the fossil record around 400 MY ago, at the beginning of the Devonian, as terrestrial ecology changed to allow the colonization of the land.

Then about 20 MY later, the first arboreal plants appear, and insects developed wings (probably from ancestral gills – the same genes are now involved in the development of arthropod gills and insect wings). However, things really went crazy in the middle of the Carboniferous, when seed plants first appeared, and the insects underwent a massive diversification, or “radiation” as paleontologists call it.

In this period, all of the major insect groups appeared, with only one (the Palaeodictyopterida – they looked a bit like dragonflies) disappearing between then and now. Insects even breezed through the end-Permian mass extinctions around 248 MY ago, when around 95% of marine species disappeared, profiting from the changed ecosystem to undergo a further wave of radiation.

By the time the flowering plants (“angiosperms”) appeared around 100 MY ago (flowers are a relatively recent invention), the insects were established as one of the dominant features of the terrestrial ecosystem, and quickly took advantage of the new plant arrivals. Although insects (and their larvae) munch through plants, the relation can also be mutually beneficial, especially with regard to pollination. Flowering plants generally provide a sucrose reward (nectar) for insect visitors, which in turn inadvertently carry off pollen to other plants of the same species, spreading the genes about. This mutually beneficial relation is shown by the parallel radiation of angiosperms and lepidopterans (butterflies and moths).

Darwin famously predicted that the comet orchid, which has an amazingly long “nectar spur” (the structure holding the nectar – it can be over 30cm long), must be pollinated by an insect with an equally long proboscis. He was right – it turned out to be the nocturnal hawk moth, with a 35cm long proboscis.

But what happened before there were flowers? Did insects simply eat the gymnosperms and ginkos that covered the Earth, or were they still involved in pollination – and how? Were all plants simply wind-pollinated?

Two recent discoveries give some insight into this. First, back in November, a stunning set of fossils was described in Science, showing in exquisite detail the mouthparts of some Mecopterans – scorpion flies. Nowadays they are a pretty insignificant bunch of around 600 species (and, of course, they are not flies…).


The fossils (and contemporaneous amber specimens) showed long, flexible probosces, and sucky ends that the insects could have used to suck up nectar-like substances produced by gynmosperms. The authors, led by Dong Ren of Capital Normal University, Beijing, conclude:

The presence of scorpionfly taxa suggests that siphonate proboscides fed on gymnosperm pollination drops and likely engaged in pollination mutualisms with gymnosperms during the mid-Mesozoic, long before the similar and independent coevolution of nectar-feeding flies, moths, and beetles on angiosperms.

Now another insight into unusual pollinators has come from Reunion Island, down in the south Indian Ocean, next to Mauritius (despite its distance from Europe, Reunion is part of France). Writing in the Annals of Botany, Claire Micheneau describes how she set out to find out how an unusual orchid, Angraecum cadetii (related to Darwin’s star orchid), was pollinated. [See also this BBC page.] They discovered that the animal responsible was an unusual – and unnamed – cricket with unusually long antennae:

These crickets, which are nocturnal foragers, reached flowers by climbing up leaves of the orchid or jumping across from neighbouring plants and probed the most ‘fresh-looking’ flowers on each plant.

They even provide a video, which should be visible below (although perhaps not to readers outside the UK; try here if not):

This is the first time that a cricket has been described as a pollinator, but it gives some indication of the variety of ways that pollination could have taken place even before flowers.  Orthopterans (crickets and grasshoppers) appeared at the same time as the gymnosperms; although people generally assumed the insects would have eaten the plants, the example of the scorpion flies suggests they might also have played a role in pollination.

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Filed under Ecology (scientific), Fossils, Insects

MASSIVE PLIOSAUR FOSSIL

The amazing “Jurassic Coast” in Dorset/Devon has thrown up another fantastic fossil – the skull of a massive pliosaur, which would have been perhaps 15m long. To be honest, the fossil isn’t much to look at (a load of rock), but it’s a pretty impressive find. Pliosaurs, in case you don’t know, were short-necked marine reptiles. Together with their relatives the plesioaurs (with long-necks, which look like the Loch Ness Monster) they ruled in the seas up until shortly before the end of the Cretaceous. There’s a great fossil plesiosaur and a model in the Manchester Museum. And no, they were not dinosaurs, which neither flew nor swam.

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BBC page, includes video (probably not visible outside UK)

Adam Smith’s fantastic Plesiosaur site

Adam Smith podcast on is Nessie a Plesiosaur and other (more serious) things:

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Filed under Dinosaurs, Fossils, Oceans

NEW FOSSIL – 1

November 2007

New ape fossil from around 10 million years ago, a close relative of the last common ancestor of humans, gorillas and chimps. BBC summary.

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Filed under Evolution, Fossils, Primates

NEW FOSSIL – 2

November 2007

Mike Taylor, a PhD student from Portsmouth was rummaging around in the basement of the Natural History Museum – the way you do – when he came across a new species of sauropod dinosaur, now called Xenoposeidon. Or at least, one of its vertebrae.

Guardian summaryBBC summary.

Blog by Mike Taylor, including loads of material on sauropod vertebrae. One person’s nerdy obsession is another’s fascinatingly detailed account. You decide.

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Filed under Dinosaurs, Fossils

ALL THAT FROM A TOOTH

November 2007

A tooth found in India suggests that ungulates – hoofed mammals – existed in India before the end of the Cretaceous (ie before the end of the dinosaurs), while the sub-continent was charging across the Indian Ocean towards its current destination. They may even have originated in India. This tooth was found in the lava of the Deccan Traps (this will mean something to those who were paying attention in The Evolution of Animals).

Article from Science (subscription needed to get past abstract).

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Filed under Fossils, Mammals

EUROPE 1.8 MY AGO – BBC GETS IT WRONG?

November 2007

Giant hyenas, giraffes and sabretooth cats roamed around Southern Spain 1.8 MY ago. A great collection of fossils have been unearthed at Fonelas in Granada.

BBC article. Scroll down the BBC page – what’s wrong with the picture of the sabretooth?

Highlight from here to the bottom of the post to read the answer: The upper canines were behind the lower canines – just like in a modern cat. This doesn’t look anywhere near as scary, so most modern pictures of sabretooths – and indeed, prehistoric images – have the big upper teeth at the front.

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Filed under BBC, Fossils, Mammals, Quiz

SPIDER DAVE DIGITALLY DISSECTS

November 2007

Dr David Penney, from the School of Earth, Atmospheric and Environmental Sciences, a.k.a. Spider Dave, has used Very High Resolution X-Ray Computed Tomography to dissect a 1mm spider that has been preserved in amber for 53 MY. Amazing pictures. The spider is a male. How can you tell?

BBC news item; original Zootaxa article (open access).

Quiz answer – highlight this line: Male spiders have little bobbles on the end of their palps; they use them to transfer sperm (don’t ask).

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Filed under Chelicerates, Fossils, Quiz

DYNAMITE FOR DINOSAURS

November 2007

Nature magazine article about a palaeontology project in Alaska, where they are blasting out hadrosaur bones from underneath the permafrost – a bit different from the normal image of people using paintbrushes under a baking desert sun… Mind you, they do end up with paintbrushes in the end.

You or your institution will need a subscription to see the page, but you can watch this video about the expedition for free.

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Filed under Dinosaurs, Fossils, Videos

AMAZING REPTILE IMPRESSION

November 2007

Seeing fossilized trackways is always cool, but this unique fossil from Pennsylvania shows body impressions of 330-MY old amphibians. Is it one animal or two? How was the fossil made?

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Filed under Amphibians, Fossils, Images