Saturday, 29 August 2020

Tuatara Genome Revealed

Tuatara Genome Revealed 

A correspondent has brought THIS ARTICLE to my notice. It tells of how the genetic material of the tuatara was collected, in collaboration with the iconic species Maori guardians. Without their cooperation the material could not have been gathered. 

The genome is 50% larger than the human genome and is one of the largest ever published. One purpose was to reconstruct the creatures evolutionary tree.

A tuatara in New Zealand. Credit: Pete Oxford/NPL

And here is its evolutionary tree - the simple version.
 Refining the evolutionary tree for reptiles, birds and mammals. This phylogenetic tree includes six branches: mammals and five branches within a clade called sauropsids, which comprises reptiles and birds. One of these, the Rhynchocephalia, has only one living member, the tuatara. Gemmell and colleagues date the divergence of the Rhynchocephalia from the Squamata to about 250 million years (Myr) ago

And here is the more complex version, taken from THE ORIGINAL PAPER.

a, The tuatara, (S. punctatus) is the sole survivor of the order Rhynchocephalia. b, c, The rhynchocephalians appear to have originated in the early Mesozoic period (about 250–240 million years ago (Ma)) and were common, speciose and globally distributed for much of that era. The geographical range of the rhynchocephalians progressively contracted after the Early Jurassic epoch (about 200–175 Ma); the most recent fossil record outside of New Zealand is from Argentina in the Late Cretaceous epoch (about 70 Ma). c, The last bastions of the rhynchocephalians are 32 islands off the coast of New Zealand, which have recently been augmented by the establishment of about 10 new island or mainland sanctuary populations using translocations. The current global population is estimated to be around 100,000 individuals. Rhynchocephalian and tuatara fossil localities are redrawn and adapted from ref. 1 with permission, and incorporate data from ref. 2. In the global distribution map (c, top); triangle = Triassic; square = Jurassic; circle = Cretaceous; and diamond = Palaeocene. In the map of the New Zealand distribution (c, bottom); asterisk = Miocene; cross = Pleistocene; circle = Holocene; blue triangle = extant population; and orange triangle = population investigated in this study. Scale bar, 200 km. Photograph credit, F. Lanting.

 The papers are interesting as they give an insight into modern biology. 

Down to Earth Extra - September 2020


DOWN TO EARTH EXTRA - September 2020

The latest edition of Down to Earth Extra is HERE.

And you can read it below.

Wednesday, 19 August 2020

Zoom Geological Webinars from Cardiff University

 Zoom Geological Webinars from Cardiff University

The School of Earth and Ocean Sciences at Cardiff University is organising a series of Zoom webinars, held at 5PM on Wednesdays.

You can read all about it HERE. Instructions on how to join the webinar are on the site.

I have missed the first couple of seminars but the full list is as follows:- 

Dave Green's Geostudies Programme

 Dave Green's Geostudies Programme

In these uncertain coronavirus times, Dave Green has boldly gone and put together a programme for the rest of this year and next. Let us hope it can go ahead as planned! Dave can be contacted HERE.

Dave writes:-

Saturday, 15 August 2020

Landslides and the Railways

Landslides and the Railways 

There has been much on the airwaves and in the papers about the dangers climate change induced landslides pose for the railways. A correspondent sent me THIS which shows that the same concerns have worried people in the railway industry, over the years. 

The paper covers the methods used to determine where conditions are suitable for landslides to occur. It does not present its results in sufficient detail to see whether the place where the recent derailment near Stonehaven was classed in its hierarchy of landslide possibilities. That was not its purpose.

But Network Rail and the BGS do have that information. This will show whether the area was a risk. But it will not tell you that a landslide will occur on a particular day. I suspect that predicting landslides is similar to predicting earthquakes!

Tuesday, 11 August 2020

Ocean-going Crinoids

Ocean-going Crinoids 

Those well known fossils, crinoids, are often found attached to, what are now, small pieces of coal. Originally these were pieces of driftwood.

Fossil crinoid attached to coal

William Buckland (and very possibly, Mary Anning) suggested that the crinoids had been attached to pieces of driftwood while alive, living suspended underneath it. For many years this was thought to be an impossibility - the weight of the crinoids would have caused the driftwood logs to sink.

But the author of THIS ARTICLE, and his co-workers, using many different sorts of advanced techniques, has worked out that crinoids do indeed hang suspended underneath the driftwood but clustered towards one end of it. Such a log could drift for ten to twenty years.

So now we know! The original article is HERE

Artists impression of a crinoid raft.

Friday, 7 August 2020

What was Tanystropheus?

What was Tanystropheus? 

A correspondent has brought THIS ARTICLE to my attention. And the answer, according to the researchers, is an aquatic creature. And not one I would like to meet in a non-fossilised form - it was active 242m years ago. It was up to 6 metres long, with a long stiff neck. Fortunately its head, and teeth were small.

The researchers conclude that there were two species of Tanystropheus - the larger hydroides and the smaller longobardicus. The newspaper article is based on THIS ARTICLE which has all the details.

An artist’s impression of Tanystropheus, fossils of which were first found around 150 years ago. Photograph: Emma Finley-Jacob/University of Zurich/Current Biology

Thursday, 6 August 2020

Geology from your Sofa

Geology from your Sofa

In this time of enforced isolation the Geologists' Association, (the GA) has produced the "Geology from your Sofa" web page. You can find it HERE. There is a tremendous amount of stuff to read and look at.

Well worth clicking on!

Short Field Course 2020 from Dave Green

Short Field Course 2020 from Dave Green

Dave Green is suggesting a short field course of 3 excursions. I received his advertisement on the day of the first one so there are 2 awaiting your presence. 

The advertisement and details are HERE. Or you can read it below.



THIS has come across my desk and is a pleasant read. It is also reproduced below.

Down to Earth Extra - August 2020


The latest edition is a 2 page introduction to the 40 page Down to Earth magazine which is not being printed - unless you ask Chris Darmon for a specially printed one.

The 2 page Extra is HERE.

The 40 page Magazine is HERE.

If you prefer smaller downloads they are HERE and HERE

Or you can read Down to Earth Extra below.

And Down to Earth Magazine below that.