30 November 2016

Dinovember 2016, Day 30

In loving memory of Campephilus principalis, Mid-Pleistocene - AD 1944. 
Name: Campephilus principalis
Meaning: chief grub-lover
Time: Holocene, c 70 years ago
Place: southeastern United States
Size: 53 centimetres (21 inches) long, wingspan over 76 centimetres (30 inches)
Type of Dinosaur: picid piciform (woodpecker)

Hey, nobody said this was Non-Avian Dinovember! And this bird is, sadly, an extinct dinosaur just like the preceding 29 entries. Campephilus principalis, or as it is better known, the ivory-billed woodpecker, was one of the biggest woodpecker species, inhabiting the extensive swamp forests of the Deep South until the 1940s. These impressive birds needed large swathes of land to sustain themselves, and excessive logging in the late 19th and early 20th centuries destroyed their habitats, leading to the woodpeckers becoming vanishingly rare by around the '30s, and the last confirmed sighting of an ivory-billed woodpecker in the United States was in 1944. Sporadic sightings have cropped up since then, most notably around 2005 when there was rather great furore in the ornithological world about the 'rediscovery' of the ivory-bill, but any hard evidence remains to be seen. It's more likely that the magnificent ivory-billed woodpecker really has vanished into extinction, like so many other dinosaurs before it.

29 November 2016

Dinovember 2016, Day 29

'Lambeosaurines? LAMBEOSAURINES? Saurolophus
MEANS "crested reptile," sonny!'
Name: Saurolophus angustirostris
Meaning: narrow-beaked crested reptile
Time: Late Cretaceous, c 72 million years ago
Place: Mongolia
Size: 13 metres (42.7 feet) long and at least 11 tonnes (12.1 tons); some specimens may be even larger
Type of Dinosaur: saurolophin saurolophine (spike-crested flat-headed duckbill)

Saurolophus angustirostris is Asia's best-known duckbill, with many specimens known from hatchlings to gigantic adults, many coming from a site called 'the Dragon's Tomb.' There are several skin impressions known from Saurolophus angustirostris, which show raised scales along the back, and small 'basement scales' studding the skin, with occasional larger scales scattered in between. Those are the rounded scales visible on this guy. Unlike many other duckbills, like Lambeosaurus the similarly-named Parasaurolophus, Saurolophus and its nearest relatives did not have large, hollow crests. Saurolophus was named for the solid, spike-like crest on the top of its head, which did not contain nasal passages like the hollow-crested duckbills' wacky headgear did.

28 November 2016

Dinovember 2016, Days 24-28

Wow, looks like I got behind again. Here's five dinosaurs in one go! Let's see...

Shuvuuia: what's so great about a pair of arms?
Name: Shuvuuia deserti
Meaning: desert bird
Time: Late Cretaceous, c 75 million years ago
Place: Mongolia
Size: about 60 centimetres (23.6 inches) long
Type of Dinosaur: parvicursorine alvarezsaurid (single-clawed bird-like dinosaur)

Shuvuuia is an odd little dinosaur, part of a group initially thought to be flightless birds. These fuzzy creatures had long, narrow snouts and tiny teeth and a single claw on their extremely shortened arms. A common idea is that they would have used their claws to open insect nests and then snarfed them up; sort of dinosaurian anteaters. Here, one Shuvuuia is preening another.

Deinocheirus: why stop at just a pair of arms?
Name: Deinocheirus mirificus
Meaning: peculiar terrible hand
Time: Late Cretaceous, c 72 million years ago
Place: Mongolia
Size: about 11 metres (36 feet) long and 6.3 tonnes (6.9 tons)
Type of Dinosaur: deinocheirid ornithomimosaur (weirdo ostrich dinosaur)

For many years, Deinocheirus was one of the great mysteries of palaeontology. A pair of powerfully-clawed forelimbs, 2.4 metres (7.9 feet) long, and nothing else. What were they from? Was it a carnosaur far larger than any other, opening up sauropods like tins of sardines? Was it one of those odd ground sloth-like therizinosaurs? The arms are actually very much like the ostrich dinosaurs' - perhaps it's one of those?

Turns out that the last one was right, but Deinocheirus wasn't just a big and bulky Struthiomimus, not at all. In 2014, complete skeletons of this mysterious monster finally were revealed to the world, and Deinocheirus was more bizarre than anyone imagined. Huge and bulky, with a towering hump on its back, a spoonbill, and a very deep lower jaw. Stomach contents preserve fish and gastroliths, showing an omnivorous diet. Wild, wild stuff.

A fine feathery face on a small forest herbivore.
Name: Agilisaurus louderbacki
Meaning: [geologist George] Louderback's agile reptile
Time: Middle Jurassic, c 168 million years ago
Place: southwest China
Size: about 1.2 metres (3.9 feet) long, but the known specimen may be a juvenile
Type of Dinosaur: neornithischian genasaur (primitive-advanced beaked dinosaur)

Agilisaurus louderbacki, like many dinosaurs, is only known from a single specimen. Fortunately, though, it's a very good one with virtually all the bones represented. It's a small beaked herbivore, and remains from Russia show that at least some of these dinosaurs had feathery coverings on their bodies, so I've restored Agilisaurus with such integument here.

Desert sky, dream beneath a desert sky, rivers run but soon run dry...
Name: Alamosaurus sanjuanensis
Meaning: San Juan [County, New Mexico, where it was discovered] Ojo Alamo [Formation] reptile
Time: Late Cretaceous, c 66 million years ago
Place: Texas, New Mexico, Utah; probably Wyoming and Mexico as well
Size: complete specimens about 20 metres long (66 feet) and 16 tonnes (17.6 tons) are subadult; fragmentary remains generally considered to be from Alamosaurus suggest sizes of 30 metres (98 feet) and more than 50 tonnes (55 tons)
Type of Dinosaur: opisthocoelocaudiine saltasaurid (column-handed advanced armoured long-necked dinosaur)

The only sauropod currently known from Late Cretaceous North America, Alamosaurus is undoubtedly one of the best animals ever. It lived right at the end of the Age of Reptiles, alongside T. rex, and grew to be one of the biggest land animals. More and more remains of this giant seem to be cropping up in recent years, and hopefully more will reveal what their growth and lifestyle was like.

There's something FISHY about little Liaoningosaurus...
Name: Liaoningosaurus paradoxus
Meaning: paradoxical Liaoning [Province, where it was discovered] reptile
Time: Early Cretaceous, c 122 million years ago
Place: northeast China
Size: 34 centimetres (13.4 inches) long; whether the described specimen is an adult or not is debated
Type of Dinosaur: ankylosaurid ankylosaur (armoured dinosaur)

Recently, Liaoningosaurus has gotten some attention as a new study suggests it was semiaquatic and fed on fish, as evidenced by fish remains in its stomach, and that the described specimen (apparently, many, many other ones are known) is actually a grown adult! These claims have understandably drawn criticism, and apparently the paper does not do a terrific job of making its case. However, I don't think we should readily dismiss these claims - it honestly seems like a very plausible niche for an ankylosaur to occupy, and as more fossils are described they'll help us understand just what the natural history of this odd little armoured dinosaur was...

25 November 2016

Dinovember 2016, Day 23

The nose knows. Or some nose pun, I guess?
Name: Altirhinus kurzanovi
Meaning: [discoverer Sergei] Kurzanov's high nose
Time: Early Cretaceous, c 120 million years ago
Place: Mongolia
Size: about 6.5 metres (21.3 feet) long
Type of Dinosaur: hadrosauroid iguanodont (near-duckbill beaked dinosaur)

Altirhinus was originally considered part of Iguanodon orientalis, a dubious species of iguanodont. More fossils revealed a rather different animal, with a bizarrely high snout. This fairly large herbivore had a rather narrow beak for selectively cropping vegetation. My restoration of it was influenced as a bit of an homage to the (unfairly) rather-forgotten 2000 Disney film Dinosaur, in which the antagonistic old Iguanodon males develop tall ridges on their snouts, clearly inspired by Altirhinus skulls. The tall, forward-slanting ridge along the back in my drawing is in reference to the quite good creature design in the film.

23 November 2016

Dinovember 2016, Day 22

Unhappy that the tyrannosaurs were hogging the spotlight for short arms,
Gualicho convergently evolved a set of nubby didactyl grabbers of its own.
Name: Gualicho shinyae
Meaning: [Field Museum fossil preparator Akiko] Shinya's gualichu [a South American folkloric demon]
Time: Late Cretaceous, c 93 million years ago
Place: Patagonia
Size: uncertain, probably about 6-7 metres (19.7-23 feet) long
Type of Dinosaur: neovenatorid carcharodontosaur (oddball large carnivorous dinosaur)

Gualicho was named and described earlier this year. It's a rather bizarre South American predator known from only a partial skeleton. Its most striking feature is its arms, which have only two fingers and are very reduced in size, much like a tyrannosaur. In fact, Gualicho and its relatives, the Neovenatoridae, are of rather uncertain placement. Various features of their anatomy are reminiscent of the more birdlike tyrannosaurs, rather than the carcharodontosaurs they were initially thought to be related to. But further studies have suggested that the tyrannosaur-like features are products of that old rascal convergent evolution, and their underlying anatomy really does support a carcharodontosaur affinity. For now, the best answer is probably that neovenatorids are indeed carcharodontosaurs that occasionally developed tyrannosaur-like features, but several neovenatorids have been found recently and more work on these bizarre theropods will hopefully make their relationships more clear.

I still gave Gualicho a coat of simple feathers, as I think our best evidence is that (at least partial) feathery coverings are the original condition for dinosaurs, and that some groups lost these coverings. Even within some groups, I imagine there's probably variety in body coverings - even amongst living animals, lots of closely related species vary quite a bit in their hairiness/scales/whatever. The head and neck are necked and covered with caruncled skin, and the nubby arms themselves are bare too, and partially hidden in the shaggy feathers.

22 November 2016

Dinovember 2016, Day 21

It seems I have gotten a day behind in posting. Oh well, I'll just post them the day after then...

Kid, you got a lot of growing up to do.
Name: Abydosaurus mcintoshi
Meaning: [great sauropod specialist Jack] McIntosh's Abydos reptile [Abydos is the location where, in Egyptian mythology, the severed head and neck of the god Osiris were buried; this is in reference to the fact that several skulls of this dinosaur were discovered at the same site]
Time: Early Cretaceous, c 104.5 million years ago
Place: Utah
Size: the best specimen is a juvenile, so its adult size is unclear, but there are fragmentary remains from the site that indicate a potential large adult possibly as much as 30 metres (98 feet) long
Type of Dinosaur: brachiosaurid macronarian (tall-shouldered big-nosed long-necked plant-eating dinosaur)

In a nice little twist on the case of almost all other sauropod species, Abydosaurus mcintoshi is known from several good skulls and only a few parts of the postcrania. The type and best specimen is a juvenile but the site where it was discovered yielded bones from at least five individuals of varying ages and sizes. Here, a hypothetical adult is shown with a youngster. If you can tell by from the picture, I went with the adult have darker face stripes on some background mottling, while the juvenile is paler with faint face stripes but darker stripes down the neck. I thought perhaps the adolescents could have had a more patterned body, maybe so they're easier for adult herdmates to see, while the giant grown-ups lose this patterning and develop bolder face and throat markings for display.

20 November 2016

Dinovember 2016, Day 20

Ooh, look at Mr Fancy Frill and his secondary sex
 characteristics! Aren't we all
sooooo impressed! 
Name: Kosmoceratops richardsoni
Meaning: [discoverer Scott] Richardson's ornamental horned face
Time: Late Cretaceous, c 76 million years ago
Place: Utah
Size: about 4.5 metres (14.8 feet) long
Type of Dinosaur: chasmosaurine ceratopsid ('long-frilled' horned dinosaur)

The horned dinosaurs are well known for their elaborate horns, spikes, and frills, and Kosmoceratops is one of the most elaborate of them all. This ceratopsian had peculiar horns that seem much better suited to display than combat. The nose horn is compressed and rectangular with a blunted tip and set far back on the snout, while the fairly short brow horns curve off to the side of the face rather than pointing forward. The frill is adorned with many spikes, and its top margin has long spikes that curve downwards and make a sort of fringe. The appearance of Kosmoceratops's bizarre face is strong support for the idea that ceratopsians' horns, frills, and spikes are predominantly evolved as features for display - to intimidate enemies and rivals or to attract potential mates - more than as combative weapons.