Wednesday, 19 December 2012

Building a dinosaur: sculpting Triceratops

Crikey. Tempus fugit and all that. Following my trip to the University of Southampton to give a scientific illustration and photogrammetry workshop, I seem to have become ultra-busy. Whilst down south we popped over to the Isle of Wight and I spent a couple of days in the field and Dinosaur Isle collections and recorded several foot casts, found some vertebrate fossils and looked at  and recorded using photogrammetry the stratigraphy of one of the sites we are working on.

In the meantime, I have made some progress with the Triceratops reconstruction that I think is worth sharing. This involves taking the model into zBrush where I can start to sculpt the form using the polygon mesh as the base, adding detail and refining the anatomy. In the case of Triceratops I wanted to look closely at the manus and forelimb posture, as many times the configuration of the forelimbs is presented wrongly. Fujiwara (2009) covered this subject in an excellent paper and this is the basis for my reconstruction.

Once more, I am working on half of the model and I'll mirror and weld these two halves at some point when the bulk of the sculpt is completed, and then I will add progressively finer detail to the mesh.


I've been adding muscle definition from the research shown in the last post and have started bulking out the gut region to give the animal a bit of a belly. It's still early days yet, and there's the issue of integument and other soft tissues . . . but that's for another post.

References:

Fujiwara, S.-I. (2009). A Reevaluation of the Manus Structure in Triceratops (Ceratopsia :
Ceratopsidae). Journal of Vertebrate Paleontology, 29(4), 1136–1147. 

Thursday, 29 November 2012

Building a dinosaur: Triceratops myology

It's been a busy month as I prepare for a workshop at the University of Southampton followed by a few days in the field after which I can start writing up recent research. However, I have done some work on the 3D Triceratops project, researching how the muscles of the animal might have been configured in life. Any reconstruction of the musculature of an extinct animal will involve a degree of speculation, but we can ensure that this is informed by fact. By studying extant phylogenetic bracketing, functional morphology and the identification of osteological correlates (1) we can reconstruct the major muscle groups.

Here's the final reconstruction, and this now means I can continue with the 3D modelling of the dinosaur, adding muscle tone to the geometry via zBrush.

Triceratops horridus musculature. © Stuart Pond

Thanks to Scott Hartman for his invaluable help getting me started and subsequent comments.

Refs:

(1) Stephen L. Brusatte. 2012. Dinosaur Paleobiology. Chichester. John Wiley and Sons Ltd.

Thursday, 8 November 2012

North Carolina Museum of Natural Sciences

Skull and neck of the sphenosuchian Dromicosuchus grallator.

The reception for this year's SVP was held in North Carolina Museum of NaturalSciences, and it was a belter. The assembled palaeontologists had the run of the entire museum, the fossil prep lab was open and specimens were on display for close inspection. There was food, beer and a cake and biccy selection that was without parallel. We didnt just feel looked after, we felt loved.

Gotcha! Sauropod foot making footprint. Great to see the process of trace-making being
illustrated so prominently.

The museum warrants a post of its own for the simple reason it is one of the best I have ever been in. The discovery centre, which is attached to the museum is a shining example of what can be achieved with good museum displays. There are labs with glass walls so visitors can see actual scientists (!) at work. There are labs where kids (and adults) can do science themselves and there are many interactive displays dotted around to keep the kids interested. Most of all, there is lots of stuff on display. Real stuff like fossils, skeletons and the tool of the scientists who collected the data, from picks and shovels to the latest technology. Its all well-labeled, well lit and organised beautifully.


The skull of the Acrocanthosaurus atokensis specimen. Nice mount.

The dinosaur exhibit is superb; a fine Acrocanthosaurus atokensis skeleton, a Pachycephalosaurus, an Edmontosaurus but best of all is the Thescelosaurus, Willo, with it's might-be-a-heart concretion (although I thought the ossification between the ribs was more interesting). Mammals are well-represented with the spectacular skeleton of a giant ground sloth (Eremotherium eomigrans) lurking unexpectedly around a corner.

The famous Thescelosaurus Willo, with the 'heart' concretion clearly visible in the thoracic cavity.

Also on display the museum had an excellent live collection based in the native fauna of North Carolina. Some of these animals were displayed in isolated tanks, but many were housed in tanks that had been incorporated into various full-scale dioramas of a North Carolinan forest ecosystem, with each zone of habitation from above the canopy to the understory represented. This allowed the visitor to see native animals that might be too shy or too well-camouflaged in their natural environment. My personal favourite was the Hellbender, a large salamander that lives in the clear mountain streams of the Great Smoky Mountains. As we were there at night many of the nocturnal animals were out from under their rocks; we ventured back the morning we flew home and many of them were under their rocks or snoozing in the leaf litter, including the Hellbender, who was tucked under a log. All the animals looked very healthy and had adequate enclosures.

Amphumia means, an aquatic salamander with vestigial limbs, native to North Carolina.

My favourite exhibit? Tucked away in a dark corner of one the labs and against one of the glass walls was a superb exhibit featuring a colony of dermestid beetles cleaning a Harbour Seal skeleton - brilliant. I wonder how they’re going on?

Two Longnosed Gar and a Pumpkinseed fish share a tank.

If you are in the Raleigh area I highly recommend a visit to the North Carolina Museum of Natural Sciences, but make sure you leave yourself plenty of time to become absorbed by this excellent museum.

A Greater siren, Siren lacertina squints through the glass at some bloke taking it's picture.

Monday, 29 October 2012

SVP field trip: Basins of the Newark Supergroup


SVP field trips have earned a reputation as being high-quality and fascinating excursions guided by knowledgeable experts who understand the locations visited and their wider context within paleontological research. They often give the attendees access to museum collections and other behind-the-scenes insights at relevant institutions, which allow you to see great stuff not on public display, and they often take you to sites that might not always be accessible otherwise. This year's trip entitled Exploring Newark Supergroup Basins in North Carolina and Virginia was no exception.

The group study the exposures at the Virginia Solite Quarry.

 The Newark Supergroup was deposited in the Triassic as a series of rift basins extending from the Gulf to Canada, and North Carolina and Virginia have the southernmost surface exposures. We visited sub-basins in two of these basins over the three-day trip, the Dan River basin and the Deep River basin.

We were led by Andy Heckert (Appalacian State University), Nick Fraser (National Museums Scotland) and Vince Schneider (North Carolina of Natural Sciences), with on-site guidance at a couple of sites from Russ Patterson, a veteran local collector with unparalleled knowledge of these sites. We were driven by Jerry Reynolds, who is also a naturalist and was of great assistance to those of us who are unfamiliar with the flora and fauna of North Carolina and Virginia.

There were twenty-two of us on the trip, which meant most of us fitted into Jerry's bus with a couple of others in the van driven by Andy. We set off from the Marriott early on Sunday morning for three days of Triassic goodness, heading firstly to the Triangle quarry.

Unfortunately the Triangle Quarry owners had pulled our permission to enter the quarry the day before, so we had to be content with standing outside where the leaders gave an excellent introduction to the geology of the Newark Supergroup and showed us some of the fossils we would be looking for. We then headed back to the North Carolina Museum of Natural Sciences for a look in the collections (always a real treat) and then lunch.

A phytosaur tooth found by the author at the Little Egypt site.

 After eating we headed out to Jordan Lake to examine a small outcrop on the margin of the lake for around 15 minutes before heading off to the spoil heaps of the Little Egypt mine of the Sandford Fm, where we were guided by NC resident Russ Patterson, who gave us a description of the site, the works that had been here, what exposures were present and what to look for. This proved to be a most fruitful spot, and as we scraped away the accumulated detritus of the forest floor we exposed slabs we could split with hammers. We found phytosaur teeth and conchostracans in the shales, black widows and ring-necked snakes in hidey-holes.

The road construction site, with blocks blasted from the Crumnock Formation on the right.

 Our final stop that day was at a road construction site, where thousands of large boulders that had been blasted out of the Crumnock Fm during construction were piled up at the road margin, awaiting processing for hard-core. These boulders contained rare bones and occasional trace fossils, and we spent some time prospecting these piles of rocks. Several small bones were found, and I recorded some ichnofossils present in the hard, red sedimentary rock. Dinner that night was in the Cafe Vesuvio, and we all enjoyed a beer with a fine meal.

A quarry opened by some of the group at the Boren Clay pits.


Next day saw us team up with Russ again at the Boren Clay pits, an overgrown and partially flooded site (great for raisin’ skeeters!) with plant remains in the sandy upper layers of the outcrop of the Pekin Fm we were prospecting. We then set off for Alton Creek, which we reached after a short hike through the woods. This was a small outcrop of Crumnock Fm shales eroded by the creek, and here we found well-preserved conchostracans. We also found an Eastern Box Turtle, (Jerry thought it was a male, around 10 years old) who didn't appreciate the attention he was getting and subsequently closed his hinged plastron very tightly for the duration of our visit.

The rather charming Eastern Box Turtle found on at Alton Creek,
photographed just before he decided to shut out those pesky palaeontologists.

Then it was off to a road cutting on Highway 220, close to the Dan River. This site, with it's fine-grained and easily-split shales yielded a diverse range of fossils including ostracods, conchostracans, coprolites, vertebrate teeth and at least one fish scale.

Prospecting the cut close to the Dan River Bridge on highway 220.

We finished the day at the Virginia Museum of Natural History in Martinsville, where Alton Dooley led us around the excellent collections and who then fed and watered (beered?) us most satisfactorily before we retired to the characterful Dutch Inn.

Tranytrachelos tail found at the Virginia Solite Quarry.
Note the linear traces to the immediate right of the tail, which
appear to have been made when the tail moved over the sediment.

The Virginia Solite Quarry was our next location and this proved to be most exciting. Next to the site office is a large block containing ripple-marks and several Grallator trackways. The quarry section we were there to see consists of seventeen 20,000 year-old sedimentary cycles of the Upper Cowbranch Fm that are tilted at around 50 degrees. These grade from dark shales at the base of each cycle to massive sandstone beds at the top, and several beds are known to contain fossils. Some of these had been exposed in a trench excavated a few years previously and now sectioned by the quarry rim and most of the crew headed up to start digging there, however three of us stayed on the quarry floor where we searched the blocks for ichnofossils, the best of which were found by Beth Southwell and we interpreted as small tetrapod swim marks. However, the undoubted highlights of this site were the Tranytrachelos fossils found by several of the crew. This small, long-necked semi-aquatic tetrapod has bene found with soft tissue and whilst we didn’t spot these in our samples, after an hour or so of digging several partial specimens of this animal had be recovered.

A small tetrapod swim trace found at the Virginia Solite Quarry site.
We found several of these very small tracks in the fine-grained sediments of the quarry.

 Finally we headed back (via the VMNH) to Raleigh and the start of the SVP.

Big thanks to the trip leaders Andy, Vince and Nick, who proved to be excellent guides to this part of the Newark Supergroup. Extra kudos goes to Nick who stepped in for Paul Olsen who was supposed to lead but was prevented from doing due to family reasons. Thanks also to Alton at the Virginia Museum of Natural History, Jerry the driver and identifier of flora and fauna (as well as his fascinating explanation of how to handle venomous snakes) and Russ for being so generous with his extensive local knowledge. One of the great things about this trip was the amount of time we spent prospecting and digging and it really felt like we’d been doing good fieldwork during the three days we spent out and about.

Finally, a big thanks to the other attendees for being such excellent company for three days; as with Utah last year it feels like I've made good friends and I look forward to our next meeting, and perhaps working with them in the future.

Wednesday, 24 October 2012

The SVP goes south: Raleigh, 2012

I returned home Monday morning, jet-lagged but happy after attending the SVP's annual meeting which was held in Raleigh, North Carolina this year. We went on a field trip to the Newark Supergroup of North Carolina and Virginia for the three days prior to the meeting start, and that will get a post of its own next time, but despite there being some excellent reviews of the meeting (see Brian Switek's write-up here) I thought I'd blog my own observations.

The venue was the Raleigh Convention Center, a cavernous building in downtown Raleigh, with the poster sessions and trade exhibitors in a room in the lower part of the centre, and the talks in the three ballrooms on the upper level. Apart from the cost of the beer, the fact the wi-fi was nearly $20 a day caused some dissent amongst the ranks, as many of us are tweeters and bloggers and wanted to communicate the science to the world outside. To their credit, the Convention Center dropped the charge after a day or so and those so inclined could tweet without incurring cost and the meeting was all the better for it.

The meeting reception was held in the North Carolina Museum of Natural Sciences, and this proved a real treat. So much of a treat, I'm going to blog about the museum separately as a paragraph or two will not do it justice. Watch this space (and twitter).

Of course, the science was the star and we weren't disappointed with a full programme of excellent talks and poster sessions. There were too many highlights to list them all but I really enjoyed Parson's talk on the flexibility of Deinonychus' neck, Brent Breithaupt's discussion on the accuracy of photogrammetry when compared directly with Lidar and Kevin Padian's presentation on pterosaur tracks, or lack thereof. As has been said elsewhere, you can't be in two places at once and so I missed several talks I would have like to have seen, however it's to the credit of the SVP they can put on so many high-quality talks you can't see them all.

The poster session venue and trade stalls.

The poster sessions were also of the usual high quality, with personal highlights being Tony Martin's description of  Alligator mississippiensis dens on St. Catherine's Island, Georgia; Peter Falkingham's deconstruction of one of Hitchcock's dinosaur footprints, Lin's intriguing take on track interpretation using methods used by civil engineers and Gatesy's X-Ray analysis of track formation (no apologies for the ichnological bias).

The trade stalls were good this year too. The Black Hills Institute had a full-sized Gorgosaurus on display (it was fascinating to watch them take it down on Sunday afternoon) and Greg Dykstra of Paleomill were showing their astonishingly good 3D printing technology. David Bergman was there with a full stock of pale-related titles (damn that paltry baggage allowance) and Skulls Unlimited were displaying their usual comprehensive stock of real and replica skulls (my Alligator mississippiensis skull replica is now sitting proudly on the sideboard).

Also present was Viktor Deak of Anatomical Origins, whose work is currently starring on the BBC's superb Prehistoric Autopsy. Viktor is a massively talented artist and sculptor who has been fascinated by human anatomy since being a small boy and the realism achieved in his sculptures is remarkable. On Friday afternoon there was even a Neanderthal woman wandering around the venue, club and all. No-one mentioned admixture.

Stu bangs on about dinosaur tracks to this bloke who kept hanging around Viktor Deak's stall,
and whose name was Neil Der Thall or something. Note Neil's glazed expression.

After last year's meeting in Las Vegas, the Raleigh meeting seemed far less glamorous but also more studious, only punctuated by frantic searches for coffee, food and beer, the essential requirements for palaeontological idea exchange, catching up with colleagues and friends and networking. Plus it had chairs which, er, tooted when you sat down on them (recorded for posterity here). It was fun with fringe meet-ups of tweeters and bloggers (both of which I unfortunately missed), great discussions in the bar of the conference hotel and the banquet and party. The auction was chaotic and lots of laughs were had (as well as bargains) and a goodly amount was raised.

The SVP 2012 banquet and awards ceremony. See those chairs? Parp!


Criticisms? Only that in this day and age videos should always play first time in presentations. Although some people play it safe and leave videos out much modern research benefits from being displayed by moving images and whatever the reason for the problem, it should be addressed pronto. If it plays in the ready room, it should play in the session.

So next year it's Los Angeles, the year after here in Europe at Berlin. I can't wait for either of them and hopefully will be able to get to them both. I love the feeling of getting home and your head still buzzing from the excitement of learning so much which informs your own research, invites questions leading to new research and most of all makes you realise the people that make this event happen, who attend and share their work and become friends and co-workers are really quite special.

Wednesday, 3 October 2012

Point clouds and palaeontology: DigitalFossil 2012

Museum für Naturkunde, Berlin.
Sunday 23rd September saw the start of the first ever DigitalFossil 2012 conference hosted at the Museum für Naturkunde in Berlin. The meeting brought together workers from across the world who are using digital techniques in their research and facilitated discussions and exchanges of ideas via talks and workshops. The venue itself was an inspiration of course, and frequent trips were taken to gaze at the Berlin Archaeopteryx, probably the most beautiful and iconic of all fossils; in real life it was more stunning and detailed than I ever imagined. The reception in the evening in the dinosaur hall got events underway was a good icebreaker as we gathered beneath the gaze of Giraffatitan brancai, sipping beer, nibbling nibbles, renewing old friendships and forging new ones.

The evening reception in the Museum's stunning dinosaur hall.
Brachiosaurid-induced cricked necks ensued.


There were plenty of highlights in the talks too, and it was soon apparent that this is a very exciting time for digital palaeontology and the pace of development of new technologies and techniques is making it a very interesting field to be working in at the present. There was lots on CT and micro-CT, some of it quite jaw-dropping due to the resolution being achieved, several talks about curating the data and disseminating the results of research via web sites and databases (including the brilliant Antweb). There was also discussions on subjects such as the need for a universal 3D file format to ease data sharing and curation (a debate that is vital), navigating through the Creative Commons labyrinth and retaining downstream flexibilty when gathering data using digital techniques.

There were a number of talks about the reconstruction of extinct organisms using digital data as the primary source and using digital techniques. Being a scientific illustrator myself this was of particular interest to me and I learnt a lot from all these talks and it's always fascinating to see how other artists work; here is the genesis of a new paradigm for the visual communication of research.

Blatant self-promotion interlude:
I present The Ichnologist's Guide to 3D models: from the field to the cloud.

I'm glad to say that photogrammetry was also discussed at length and the whole first session was given over to talks discussing various techniques and technical issues. I gave my first ever conference talk, which was about photogrammetry workflow and also co-presented a photogrammetry workshop in the afternoon with experts Neffra Matthews, Brent Breithaupt and Peter Falkingham; both went well and we received good feedback, and all the photogrammetry talks were fascinating.

The photogrammetry workshop recording data from the display of Chirotherium trackways.


There were various demonstrations throughout the three days of the meeting, including Lidar and various scanning technologies, although with the notable exception of Peter Falkingham's excellent discussion of the use of Kinect as a scanner all of these are out of the price-range of a self-funded researcher such as myself.

This brief review of DigitalFossil2012 does not do justice to either the work of the organisers or that of the presenters whose talks were so informative and thought-provoking. I highly recommend you check out the abstracts online to find out more about what was discussed. You know you've been to an excellent meeting if you come out with your head buzzing and plenty of ideas of how to incorporate these into your own research; my head is buzzing still.

Finally, a big thank you to Heinrich Mallison and his team at Museum für Naturkunde for their tireless work preparing and hosting the conference.

Friday, 21 September 2012

Chirotherium footprint in 3D

Here's a 360-degree animated view of a superb Chirotherium footprint cast I recorded on my recent trip to Manchester Museum's ichnology collection.

video

Notice the prominent claw marks and well-preserved nodes on each digit. Digit V is present but not quite as well preserved, and shows this is a left foot print. What is especially interesting about this particular print is the length of the footprint; aside from the impressions of the digits which are often seen in specimens of this ichnotaxa, there is a well-defined u-shaped bulge, the hindmost margin of which is approximately 240mm from the tip of digit III. Could this represent the heel of the foot? Well, I'm not so sure and I hope to have a closer look at this print when time allows. The distance to the fracture is around 169mm.

The techniques used to record this fossil (and other digital methodologies) will be discussed in talks and taught in workshops at DigitalFossil 2012 in Berlin, which starts on Sunday. It will be well worth visit if you're interested in the digital techniques currently being used and under development and their applications in palaeontology and ichnology.

Sunday, 9 September 2012

Tracks from the Triassic: Isochirotherium in 3D

I spent a fruitful morning in the ichnology collections at Manchester Museum last week, where I had gone to look at some examples of invertebrate trace fossils that can be found in the local area and which might be a basis for future research. I was also looking at local vertebrate footprints from the Triassic and whilst there took the opportunity to photograph some of dinosaur footprints housed in the collection.


video

Here is a 360-degree rotation of a particularly fine print of Isochirotherium lomasi, an enigmatic archosaur known only from its tracks and recorded using photogrammetry during a previous visit. The museum has a fine collection of these prints and this particular one is on public display in the fossil gallery and comes from a site on the Wirral in north-west England, an area which has produced many tracks over the years. This is a left print as the 'thumb' is actually the outermost digit of the pes (or manus), and is very similar to the ichnogenus Chirotheruim, a fact that led no less an anatomist than Richard Owen to conclude the thumb was digit I and thus Chirotherium walked cross-legged, and it took until 1925 until Wilfred Soergel established that this 'thumb' was indeed the outer digit.

Many thanks to David Gelsthorpe, Curator of Earth Science Collections (@paleomanchesterand Kate for their invaluable help whilst I was there; they made me feel very welcome and I look forward to going back. More goodness from the excellent Manchester Museum collections to come.

Thursday, 23 August 2012

Using photogrammetry to capture data in the round


video

With DigitalFossil 2012 in a few week's time it seemed appropriate to post some of the work I've been doing recently. Part of this has focussed on creating a workflow for capturing data a full 360-degrees with minimal loss of data, which leads to holes in the mesh and distortions. By way of an illustration here is an animation of an early 360 capture of the cast of a Conchoraptor sp. skull, showing the wireframe, mesh and textured model. It loops seamlessly for your viewing pleasure.

Friday, 17 August 2012

Neoichnology in the desert

Here in the UK we're a little short of deserts, so whilst in the US for last year's SVP we took advantage of visiting the Mojave and spend some time with the SVP field trip in Utah and northern Arizona. Below is a small selection of tracks we encountered whilst out and about.

Arthropod track. Coral Pink Sand Dunes, Utah.


Arthropod track. Coral Pink Sand Dunes, Utah. Notice other tracks crossing nearly perpendicular to
the double-lined track, possibly an arachnid trace.


Kangaroo Rat. Coral Pink Sand Dunes, Utah.


The Beehives, Valley of Fire, Nevada. This trackway, which obviously belongs to a large mammal
was a few hundred yards away from the car park. Note the paired footprints and tail drag mark.

Close-up of one of the footprints from the trackway pictured above.
Could this be a coyote trackway?

Finally . . . ichnology courtesy of the old ones. Vicinity of Atlatl Rock, Valley of Fire, Nevada.
My wife spotted this track on the underside of a large fallen boulder that had petroglyphs on the outer face. Note very narrow pace angulation, deep impressions and displacement rims suggesting
soft substrate and possible bioturbation traces on the surface. A beauty of a track
but we had zero time to record it as we were already being called back to the truck. Bah.

I wish I had more time to record all of these traces properly, but time didn't permit, especially on the Valley of Fire trip which was an excursion from Las Vegas, and was running to a strict schedule. Also, I wasn't so ready for photogrammetry at the time, now it would be very different!

Tuesday, 31 July 2012

Encounters with wildlife in the field

There's no doubt that seeing wildlife whilst doing fieldwork is one of the most exciting, entrancing and memorable experiences for a palaeontologist. Fieldwork helps a person feel a strong connection to the landscapes they work in, and seeing the animals and plants that actually live there is a massive thrill.

This set of photographs are records of some of the encounters I've had whilst engaged in fieldwork. I make no apologies for the bias to US species, as these trips had so much wildlife it was quite astonishing, and of course novel to have so many species of large mammals, reptiles and birds of prey to observe as we travel through and work the badlands. You might notice the images from North Dakota and Montana are surprisingly green for late June, this is because of the exceptionally damp year so far. As local garage owner Jim Martin said "You can tell it's been a wet spring when the clover's high on the gumbo banks".

Sea anemone (Sagartia elegans), Isle of Wight. Found in a rock pool whilst looking for dinosaur bones.

Bighorn Sheep, Zion National Park, Utah.
We came across a herd of these whilst on the 2011 SVP field trip.
I'm not sure, but I think this might be the subspecies Ovis canadensis nelsoni, or Desert Bighorn Sheep
which occurs in the Southwestern deserts of the US (wikipedia).

Unidentified invertebrate, Hell Creek Formation, North Dakota.
This intriguing little fellow was spotted by two of the
field crew when we went to check the sites at the start of the 2010 field season. It's head end
(unless it was in permanent reverse) is towards the top and it's around 4mm long. There was some
speculation it might be an aphid of some description, I wondered if it was a caterpillar.

Mule Deer (Odocoileus hemionus), South Rim, Grand Canyon, Arizona. Our guide Barry called these Kanab Deer, and These might be a subspecies of Mule Deer unique to Mexico and Arizona (wikipedia) known as the Desert Mule Deer, Odocoileus hemionus eremicus, although I think their range is further south. This handsome fellow was spotted from the trail that heads east from Grand Canyon Village. There were does and fawns around too.

Common Side-Blotched lizard (Uta stansburiana), Potter's Canyon, Arizona.
This attractive lizard was not for hanging about but did pose long enough for a couple of pics.

I have to be honest, I have no idea what this is but it was found by Professor Tom Hollocher
in the badlands of the Hell Creek Formation, North Dakota.

Plains pricklypear (Opuntia polycantha). Hell Creek Formation, North Dakota. 

A young rattlesnake (unsure of the species) warns us in no uncertain terms - stay away. Montana.

Common Raven (Corvax corax), South Rim, Grand Canyon, Arizona.
These magnificent birds frequent the trails around the canyon.

Desert Striped Whipsnake (Masticophis bilineatus lieolatus). Potter's Canyon, Arizona.
This fantastic snake was spotted during an SVP field trip. A shed skin was found nearby,
and it may well have come from this animal.


I think this a Woodhouse's Toad (Bufo woodhousii), Hell Creek Formation, North Dakota. 

Wild Turkey (Meleagris gallopavo), Montana. The first time I ever saw a wild galliforme in the US was
when a pair of these wonderful birds came close to our trucks when we stopped to
chat to the landowner to get the lowdown on conditions in the badlands.

Tarantula (Aphonopelma sp.), Warner Valley, Utah. This is a male possibly out on the hunt for
a female. It was small, a wonderful blue-grey and a real beauty.

Next: Tracks and traces in the desert.

Thursday, 19 July 2012

Incidental finds in the field

One of the many joys of fieldwork is the fact you have no idea what each day might bring. Apart from the main focus of your work delivering up constant surprises, the environment you are working in is often as fascinating and throws up seemingly endless delights. If you are digging in a foreign country, then this effect seems magnified and everything around you becomes a vital part of the experience. The very nature of fieldwork means you are getting up close and personal to the land and the flora and fauna you share it with for the duration of the trip. On top of all this, there seems to be a sense of heightened awareness: in the rock you are working, the weather, the lay of the land, the sounds. . . . well, you understand. The context of the physical and mental activity that is fieldwork.

So here is the first of three posts that deal not with the fieldwork itself, but the incidental finds that over the years have attracted my attention. These may seem mundane or irrelevant and of course scientifically they are, but these finds are as much a part of the field experience as the fossils we strive to discover and understand. 


Three articulated vertebra, bleached by the sun.
No idea what they belonged too, but I'm guessing artiodactyl.
Hell Creek Formation, South Dakota, USA.

The wreck of The Carbon. Compton Bay, Isle of Wight, UK.
You need a low tide to get this close too the old metal-hulled boat, which came to grief on the rocks of the Wessex Formation, Wealden. She was a 175-ton steam tug that was under tow in November 1947 when she came loose and ran aground.

Deer leg. We saw Mule deer in the area of our quarry, but this also might be a Whitetail
or Pronghorn, both of which live on the prairie and badlands. Hell Creek Formation, South Dakota, USA.

Upper jaw fragment. Once more, I have no idea what this is from, but I'll go with artiodactyl as a guess.
Potter Canyon, Dinosaur Canyon Member, Moenave Formation, Arizona, USA.

Native American microlith. In the UK, this would come home but there are understandably
very strict laws regarding the removal of Native American artifacts, so it stayed in-situ.
Moccasin Mountain, Navajo Sandstone Formation, Utah, USA.

Petroglyphs, Fort Pierce, Utah, USA. These superb petroglyphs are carved into the desert varnish
on outcrops of Shinarump Member of the Chinle Formation.
We also heard a very loud boom at this point, possible sonic, mine or other blasting.
As for what these petroglyphs actually depict, there is plenty of debate and interpretations vary.
Where possible, I always bring incidental finds home as they act as not only objects of interest in themselves but reminders of a moment in time, which often have very happy memories. Antlers, skulls, sea glass, various sub-fossil bones, teeth, hagstones, feathers, shells minerals and one day a rather fine geological hammer all enter the collection and each has a memory attached. Wonderful.

Next: Critters

Sunday, 17 June 2012

Photogrammetry: Two dinosaur footprints from The Isle of Wight

The Isle of Wight, which lies off the south coast of England, has long been a good spot to find dinosaur footprints and other traces of ancient life. The rocks of the Wessex and Vectis Formations, part of the Lower Cretaceous of the Wealden of southern England, contain numerous examples of trace fossils of many kinds, from dinosaur footprints and invertebrate traces to palaeoenvironmental indicators such as ripples and mud cracks.

At least two distinct palaeoenvironments are represented in these formations. The Wessex Formation is interpreted as representing a braided river system complete with crevasse splay sandstones, ephemeral ponds and lakeside margins, all containing trace fossils (Naish and Martill, 2001). The deposits of the Vectis Formation were laid down in a coastal lagoonal environment and contain facies interpreted as mudflats and storm coquinas, both of which also preserve traces of ancient life (Radley and Barker, 2000).

On my last visit to the island I took the opportunity of recording some of these footprints using photogrammetry, and here are a couple of the meshes I was able to create. These are both from the trackway at Hanover Point, and are well-known; perhaps too well known as one print has been removed with a rock saw, and a second was in the process of being removed when the it finally dawned on the not-so-smart thieves that the rock was way too unstable to make the operation worthwhile, but not before one footprint was lost forever.

Figure 1: 3D mesh of tridactyl footprint from the Wessex Formation
of the Isle of Wight, UK.

Figure 1 shows the footprint that was in the process of being removed. This is the best preserved of the remaining prints. It's a tridactyl pes print, and has a distinct claw-mark on the leftmost digit.

Figure 2: 3D mesh of a second footprint from the same trackway as the footnoting illustrated
in figure 1.

The second print is much less well-defined and demonstrates how much variation is possible in footprint morphology within a single trackway.  The left most digit has one clearly defined node, the rest of the print indistinct; this might indicate the substrate might have variable texture and/or consistency, or the footprint was subject to alteration after being made. The line running throughout the print is a natural fault.

This trackway is well worth seeking out if you're visiting the island, although you'll need a low tide and some time to find them out on the rocks. Professionally guided tours are available from Dinosaur Isle. Please note it is illegal to remove or attempt to remove any footprint found on the south-east coast of the Island.

References:

Martill, D. and Naish, D (Eds). 2001. Dinosaurs of the Isle of Wight, 319pp. The Palaeontological Association, London.

Radley, J. and Barker, M. Paleoenvironmental significance of storm conquinas in a Lower Cretaceous lagoonal succession (Vectis Formation, Isle of Wight, England). 2000. Geological Magazine, 137. pp193-205. Cambridge University Press.