17 July 2015

A Visit To the McWane Science Center, Part I: Dinosaurs of the Deep South

Sorry for the long absence. Hopefully there will be new content -- including art -- here soon.

Anyway, if you should ever find yourself in Birmingham, Alabama, as my family and I did last week, a day at the McWane Science Center is sure to prove a day well spent. McWane features a museum as well as an IMAX, and most of the exhibits are geared toward kid-friendly interactivity: there is a hall of physical-science based challenges, brain teasers, and the like, an aquarium featuring a shark and ray touch pool, and space for visiting exhibits, which at the time of our trip was hosting an interesting, interactive-heavy exhibit on the history toys and games over 20th and 21st centuries. Of course, as soon as we'd paid our admission, I dragged the family up a flight of stairs to get to what we all* came to see: the dinosaurs.

A nodosaur browses amongst the ferns as an Appalachiosaurus stalks behind it.
[photograph by the author]


Alabama In the Age of Dinosaurs

One of the keystone exhibits at McWane, Alabama Dinosaurs/Sea Monsters dominates its floor space, sharing relatively little room with (admittedly really cool) exhibits on meteorology, arthropods, today's living dinosaurs, and the history quack doctoring.

The author's ugly mug mucking up a perfectly good picture of
some of the dinofauna of Campanian Appalachia. For the fashion-
savvy among you, in these photos I'm kitted out in the palaeoblogosphere's
finest, wearing Jaime Headden, with button accessory by David Orr.
[photograph by the author's mom]

When most people think of finding dinosaurs in the US, they think of mountains and deserts. Wyoming, Utah, Colorado, Montana, New Mexico -- with their rugged rock outcrops and wild terrain, they certainly seem the perfect environment for finding Mesozoic fossils, and it's true that these states are real treasure troves of dinosaur remains. However, the eastern half of the United States has a diversity of dinosaurs as well, ranging from the beautiful trackways in New England to the creatures exhibited here, all (former) residents of the Deep South. However, Alabama has a surprisingly rich dinosaur record; in fact, one of the palaeontologists working at McWane said that there might be as many as two dozen species of dinosaur waiting to be described from material that's already been collected and is mostly housed either in McWane's archives or at University of Alabama - Birmingham. The material is there, but it's never been examined as well as a lot of material from the West. Some of it has never really been examined at all. (Future grad school project...?)

A map of North America as it would have appeared during the Campanian, c. 75 Ma.
[image from Sampson
et al, 2010, 'New Horned Dinosaurs from Utah Provide Evidence for
Intracontinental Dinosaur Endemism'
, under CC Attribution 2.5 Generic licence]

During the Late Cretaceous (the animals in this exhibit lived roughly 80-75 Ma), Alabama -- along with much of the Southeast and Midwest -- was covered by a warm, shallow seaway that divided North America down its middle into two major landmasses, called Laramidia (the western one) and Appalachia (the eastern one). Dinosaur fossils in the state are collected from the 'Black Belt' region (so named for its rich soil) of central Alabama, which would have been the edge of the prehistoric seaway. The remains of dinosaurs found in Alabama are actually found mainly in sediments deposited in marine settings, and thus represent animals that were washed out to sea after death; in life, they would have inhabited coastal woods, wetlands, and savanna, in a warm temperate-subtropical climate not terribly different to coastal Alabama of the 21st century, although grass would have been absent; instead, ferns would have provided the predominant ground cover.

Meet the Mounts

Ornithomimid (centre) with dromaeosaurids.
[photo by the author]

Upon entering the Dinosaurs of Alabama exhibit area, visitors find themselves face-to-face with an ornithomimid being harried by two smaller dromaeosaurids.

Some research indicates that dromaeosaurids, famous as fleet-footed hunters,
were actually pretty slow and not suited to pursuit. An ornithomimid could
easily outpace them... but maybe not if it was taken by surprise...
[photo by the author]
Ornithomimids, commonly called 'ostrich dinosaurs' because of the obvious similarities in appearance, are a group of herbivorous/omnivorous theropod dinosaurs with toothless beaks and long legs with three-toed feet. They would have been fast runners, with some estimates putting their top speeds a bit upwards of 64 km/h (40 mph).

These dromaeosaurids might be biting off more than they can chew. Just because
ornithomimids areherbivores doesn't mean they're defenceless... this prospective
prey was probably 12-15 times heavier than one of the predators, and a kick could
easily prove fatal to a delicate dromaeosaurid.
[photo by the author]
Since most dinosaur fossils from Alabama (and from the eastern US in general) are quite fragmentary, most of the mounted skeletons at McWane are actually of closely-related dinosaurs that are more-completely known than the ones unearthed in Alabama. The mounts are, however, accompanied by displays showing some fossils that are actually known from Alabama; in the case of ornithomimids, limb bones are some of the best remains. The mounted skeleton is of Gallimimus, a Mongolian dinosaur, which at 6 metres (20 feet) long or more was one of the biggest ornithomimids and similar in size to estimates for the Alabama ornithomimid.

A dromaeosaurid, which in life would have looked very birdy indeed.
[photo by the author] 
It seems there were probably multiple species of dromaeosaurid, or 'raptor,' in Cretaceous Alabama. A variety of remains, such as teeth and claws, have been recovered. The signs estimate 2.7 metres (9 feet) for the length of (at least one kind of) Alabama's dromaeosaurs. These extremely birdlike predators would have preyed on small and mid-sized dinosaurs, as well as other animals much smaller than themselves. The mounts at McWane are Deinonychus, a well-known dromaeosaurid that lived in Montana and Wyoming about 112 Ma. I'm not sure that this was the best choice, considering how much older Deinonychus is than the Alabama taxa; I think using a more contemporaneous dromaeosaurid, such as Dromaeosaurus or (probably even better) Saurornitholestes might have made more sense. It's not a major issue, though, and one thing to rejoice about is proper positioning of the dinosaurs' hands throughout the exhibits -- palms facing inward -- which is unfortunately not a given, even in museums.

A nodosaurid among the ferns.
[photo by the author]
Moving on through the exhibit, the centrepiece is a round diorama that has two mounts. On one side of the diorama is an herbivorous armoured dinosaur called a nodosaurid. This squat, heavily-built animal is covered in bony scutes called osteoderms. Nodosaurids are well-represented in Alabama's dinofauna, with some reasonably complete remains known, the best of which come from a juvenile individual. It's possible that there was more than one species of nodosaurid in this Late Cretaceous Alabama ecosystem, but -- like so much about the dinosaurs of Appalachia -- this needs a lot more study.

Animantarx is a nodosaurid known from good remains. Size, shape, and
orientation of osteoderms varied quite a bit amongst the nodosaurids,
so Alabama's nodosaurid(s) probably had a different, unique arrangement.
[photo by the author]
The nodosaurid chosen to represent the Alabama taxon/taxa is Animantarx (one of the most evocative dinosaur names, it means 'living fortress'), which roamed western North America about 97 Ma. Animantarx is a bit small, at 3 metres (10 feet) long. Since the best-known Alabama nodosaurid was a juvenile, it's hard to say how large adults would have grown, especially if multiple taxa were present. The McWane's signs posit an estimate of 3.7 metres (12 feet) and roughly 680-907 kilograms (1500-2000 pounds) or so, with a tentative larger size of 6 metres (20 feet) and 2.7-4.5 tonnes (3-5 tons).

My, Appalachiosaurus, what big three-fingered forelimbs you have!
All the better to demonstrate the changing opinions on my phylogenetic
relationships, my dear!
And then
Appalachiosaurus gobbled him up.
[photo by the author]
The star of Alabama Dinosaurs, on the opposite side of the diorama from the nodosaurid, is Appalachiosaurus montgomeriensis. Uniquely among the dinosaurs in this display, this mount -- the largest at McWane -- is not a related animal doing a stand-in due to poor (and/or poorly-studied) remains, but an actual reconstruction of Appalachiosaurus based directly on the recovered material where possible and being informed by the animal's relatives. Alabama's best-known dinosaur, Appalachiosaurus is a tyrannosaur of somewhat uncertain affinities. Initially it was thought to be a rather primitive tyrannosauroid, which is why the skeletal mount at McWane is recontructed with large, three-fingered forelimbs: more-primitive tyrannosauroids still had well-developed forelimbs compared to the stumpy two-finged ones of the tyrannosaurids. A large humerus referred to Appalachiosaurus seemed to support this idea. Dryptosaurus, another tyrannosauroid from the eastern US (New Jersey), also sported large arms with some nastily-clawed three-fingered hands.

However, further studies found Appalachiosaurus to be much more derived than Dryptosaurus; if not a member of Tyrannosauridae, it's quite close to it. No members of Tyrannosauridae have large arms or three fingers. Furthermore, the identity of the supposed humerus is rather questionable; taken together, this indicates that Appalachiosaurus almost certainly had short arms with only two fingers. I've heard that a museum in Georgia has adjusted its Appalachiosaurus mount accordingly; I hope McWane follows suit.

Leg of Appalachiosaurus, with the inner toe to the right
of this image. Appalachiosaurus is the most-completely
known theropod from the eastern United States.
[photo by the author]
As you can probably gather from the above remarks, just where Appalachiosaurus fits amongst the branches of the tyrant dinosaur family tree is contentious. While initially believed to be a rather primitive member of the group, later analyses found it to be a derived member, maybe a part of the family of the 'advanced' tyrant dinosaurs, Tyrannosauridae, which includes the likes of a certain Tyrannosaurus. One study even recovered it as being a very close relative of the advanced 'slender' tyrannosaurids of Laramidia, Gorgosaurus and Albertosaurus, but more recent research does not support this idea. With more study and -- hopefully -- more specimens, the relationship of this dinosaur can hopefully be better resolved.

Glamour shot of Appalachiosaurus.
[photo by the author]
The only known Appalachiosaurus is an immature animal, as shown by the only limited degree of fusion between its skull bones. However, it's already quite big, at 6.7 metres (22 feet) long. Its adult size is uncertain, but was likely in the neighbourhood of 9 metres (29.5 feet). An adult likely would have weighed about 1.5-2 tonnes (1.7-2.2 tons), but between 1.2-3 tonnes (1.3-3.3 tons) seems a plausible range.

I also would like to add that Alabama's first described dinosaur, a plant-eating ornithopod called Lophorhothon atopus, was not represented in the exhibit, although it was featured in some of the signs and interactive material. It's generally thought to be a hadrosaur, or duckbill, and the original specimen was of an animal only about 4.6 metres (15 feet) long, so it was probably a juvenile. According to McWane, there are  fragmentary remains that may belong to Lophorhothon which indicate that an adult might have been very large, 12 metres (39 feet) long and over 7.5 tonnes (8.3 tons).

Overall Appraisal

The Alabama Dinosaurs exhibit, like most of the McWane Science Centre, is intended to be kid-friendly and as such has a high degree of interactivity. There is a large scale that groups of people can stand on to try to equal the mass of the different dinosaurs in the exhibit, a two-person game on modified excersise bicycles where players try to outpedal the virtual Appalachiosaurus chasing on the screen behind them, a (slightly outdated) trivia game kiosk, and a 'dig for fossils' pit for kids to uncover plastic fossil replicas and try to identify them. A few video posts around the exhibit space provide additional information, and each of the dinosaurs is accompanied by a digitally-projected sign that scrolls information.

Despite all the kid-geared stuff, none of it is integral to the exhibits and most of it is located on the fringes of the exhibit space so it's not in the way of someone strolling through. When we first went in, the electronic components of the exhibit were having some trouble and needed to be reset. Our experience wasn't hampered by their (temporary) absence, but a large group of children in a visiting summer day camp were quickly herded out of the exhibit by their chaperones because none of the electronics were working. Although it kept the space more open and quieter for us, I have to say I'm a little bothered that their chaperones thought they wouldn't be able to get anything out of the displays without videos and games. The kids actually still seemed really excited about just seeing the dinosaurs. Hm.

Alabama Dinosaurs is a very nice display that shows there's a lot more to palaeontology in the Deep South than many might expect. But it's not the whole story; since Alabama was largely underwater in the Cretaceous, this exhibit also has an expansion called 'Sea Monsters' that features prehistoric marine life of Alabama. That will be covered in a (hopefully more concise) post coming up in the next couple of days.

I'd highly recommend any palaeo-enthusiasts, or science-enthusiasts in general, to visit McWane if the opportunity presents itself. Its website is here.

Up next: A Visit To the McWane Science Center, Part II: Southern Sea Monsters.

-- M

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