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.

19 November 2016

Dinovember 2016, Days 18 & 19

Armoured Edmontonia and Dyoplosaurus pass each other amongst the ferns on
a steep embankment in what will one day be Canada's Dinosaur Provincial Park.
Name: Edmontonia rugosidens
Meaning: rough-toothed Edmontonian [the original material was found in what was then called the Edmonton Formation]
Time: Late Cretaceous, c. 76.5 million years ago
Place: Alberta
Size: about 5.8 metres (19 feet) long and 3 tonnes (3.3 tons) or more
Type of Dinosaur: nodosaurid ankylosaur (clubless armoured dinosaur)

Name: Dyoplosaurus acutosquameus 
Meaning: acute-scaled double-armoured reptile
Time: Late Cretaceous, c. 76.5 million years ago
Place: Alberta
Size: about 4-5 metres (13-16.4 feet) long, possibly larger
Type of Dinosaur: ankylosaurid ankylosaur (club-tailed armoured dinosaur)

A double dose of Dinovember, featuring a pair of armoured ankylosaurs from Canada's famous Dinosaur Park Formation. Edmontonia, on the left, is from the tail club-lacking lineage of ankylosaurs called nodosaurids. It had large shoulder spikes that would have made formidable offensive or defencive weapons. On the right is Dyoplosaurus, which was widely considered the same as the better-known Euoplocephalus until recently. It was one of the club-tailed ankylosaurids, but unlike Euoplocephalus, Dyoplosaurus had a fairly small, narrow tail club. Both nodosaurids and ankylosaurids would have relied on their tough armour and broad bodies to protect themselves from predatory tyrannosaurs.

17 November 2016

Dinovember 2016, Day 17

A big, arched nose and fun in the mud: Gryposaurus is my kind of dinosaur.
Name: Gryposaurus monumentensis
Meaning: [Grand Staircase-Escalante National] Monument hook-nosed reptile
Time: Late Cretaceous, c 76 million years ago
Place: Utah
Size: generally about 8-9 metres (26.2-29.5 feet) long and 3-4 tonnes (3.3-4.4 tons) or so, but larger material from Utah referred to this species suggests large individuals of at least 12 metres (39.4 feet) and probably 8-10 tonnes (8.8-11 tons)
Type of Dinosaur: kritosaurin saurolophine (Roman-nosed duckbill dinosaur)

Gryposaurus is a duckbill near and dear to my heart - we have very similar nose shapes. Additionally, while saurolophine duckbills are more often overshadowed by their hollow-crested lambeosaurine cousins, Gryposaurus had the big size and burly build to make it just as impressive as its more elaborately-adorned kin. These Gryposaurus are enjoying a mud wallow, something I believe many dinosaurs would have done just like many big animals today. The huge individual at the back represents the larger known material, while the smaller ones at the front still have a lot of growing to do; in most dinosaur communities, adolescent animals that were capable of breeding but still were far from 'full size' would have really dominated, as opposed to really big adult animals.

16 November 2016

Dinovember 2016, Day 16

A snake snack.
Name: Byronosaurus jaffei
Meaning: [museum supporter] Byron Jaffe's reptile
Time: Late Cretaceous, c 75 million years ago
Place: Mongolia
Size: around 1.4 metres (4.6 feet) long
Type of Dinosaur: troodontid paravian (very near-bird predatory dinosaur)

Byronosaurus was a troodontid, a group of dinosaurs with excellent hearing and vision. It lived in the desert and had a long, narrow snout with small teeth. It looks to me like it would be well adapted to snatching up small prey like snakes - which is just what this one has done.

15 November 2016

Dinovember 2016, Day 15

He's watching you.
Name: Herrerasaurus ischigualastensis
Meaning: [discoverer Victorino] Herrera's reptile from Ischigualasto [Formation]
Time: Late Triassic, c 231.4 million years ago
Place: Argentina
Size: about 3.5 metres (11.5 feet) long and 210 kilograms (463 pounds)
Type of Dinosaur: herrerasaurid theropod (primitive predatory dinosaur)

Herrerasaurus is one of the oldest dinosaurs known. Due to its early time and primitive characteristics have made its classification difficult. At various times, it has been considered a theropod, a primitive saurischian (lizard-hipped) dinosaur before the sauropodomorph-theropod split, a sauropodomorph (the lineage that would yield the giant long-necked plant-eaters), a dinosaur outside the saurischian-ornithischian split, or not even a dinosaur. Most recent studies suggest that it is in fact a theropod, and additional discoveries have revealed some similar sorts of dinosaurs.

In this drawing, a Herrerasaurus is stalking past a toppled tree, lurking under some cycad fronds. Mostly, an attempt to keep my Dinovember drawings from being too empty.

14 November 2016

Dinovember 2016, Day 14

Fancy frill.

Name: Regaliceratops peterhewsi
Meaning: [discoverer] Peter Hews's regal horned face
Time: Late Cretaceous, c 68 million years ago
Place: Alberta
Size: about 5 metres (16.4 feet) long and 1.5-2.5 tonnes (1.7-2.8 tons)
Type of Dinosaur: triceratopsin chasmosaurine (advanced three-horned 'long-frilled' horned dinosaur)

Named in 2015, Regaliceratops is a bit odd for being a very close cousin of the famous Triceratops. Instead of a long, relatively unadorned frill, a short nose horn, and long brow horns, Regaliceratops looks more like a member of the centrosaurine branch of horned dinosaurs, with a big nose horn and tiny brow horns, and a short frill that has large, rounded decorations around the edges. Perhaps Triceratops is part of a lineage that had some more weird members that await discovery.

My drawing of Regaliceratops is a based heavily on a Charles R Knight painting - perhaps my favourite dinosaur painting ever, actually - of a dubious genus of ceratopsian called Agathaumas. Agathaumas remains are almost certainly attributable to Triceratops as well as other dinosaurs, but Knight's highly speculative restoration of this creature is incredibly life-like. The large plated scales, the thick rhinoceros-like neck folds, and the overall presentation of the dinosaur make it seem as though the artist painted it at an easel set up in a Late Cretaceous meadow. Although the restoration was largely speculation, what we know now about horned dinosaur skin makes it seem pretty reasonable. I was struck by the surprising resemblance of the real Regaliceratops when it was announced to Knight's semi-fictitious Agathaumas, and wanted to pay homage to one of the great palaeoart renderings in this Dinovember entry.

13 November 2016

Dinovember 2016, Day 13

Sauropods may have had noisy noses. 
Name: Daxiatitan binglingi
Meaning: titan of the Daxia [branch of the Yellow River] from Bingling Temple [famous site near where it was found]
Time: Early Cretaceous, c 122.6 million years ago
Place: northwestern China
Size: about 23 metres (75.5 feet) long and 20-25 tonnes (22-27.6 tons)
Type of Dinosaur: euhelopodid macronarian (very long-necked big nosed plant-eating dinosaur)

Despite initial claims of extreme size, Daxiatitan does not appear to be one of the largest dinosaurs of all time, attaining a size that, while certainly respectable, is not all that giant among the sauropods. It belonged to a derived group of sauropod dinosaurs with extremely long necks and long forelimbs that is so far only known from Asia.

In this picture, I imagined a male Daxiatitan, at back, courting a female by making a bellowing call and inflating colourful flaps of skin around his nose and along his neck. Both sexes have similar patterns though.

12 November 2016

Dinovember 2016, Day 12

I guess you can pick which one is Elvis and which ones are Jordanaires. 
Name: Cryolophosaurus ellioti
Meaning: [geologist David] Elliot's frozen crested reptile
Time: Early Jurassic, c 190 million years ago
Place: Antarctica
Size: about 6.5 metres (21.3 feet) long, but the known specimen is a subadult
Type of Dinosaur: uncertain, but probably a tetanuran theropod (advanced stiff-tailed predatory dinosaur)

Antarctica probably teemed with dinosaurs over the Mesozoic Era, but its frigid climate makes palaeontological work there very difficult. Cryolophosaurus is one of only a handful of dinosaurs to be excavated from the continent, and the first Antarctic dinosaur to be named and described. A popular nickname for this predator is 'Elvisaurus,' in reference to the tall, forward-swept pompadour-like crest on top of the head. This structure was too breakable for any physical combat but would've made a brilliant visual signal.

Here I've illustrated a fluffy family of Cryolophosaurus - with slightly different crest sizes and shapes to indicate differences between sex, age, and individual condition. The feathery-fuzz coatings are speculative, but Antarctica would've been quite chilly, even during the mostly-steamy Early Jurassic, so these dinosaurs probably would have benefited from the added insulation.

Dinovember 2016, Day 11

Sorry, got a day behind in posting. I'll post two in a row here...

The Terror of the South, looking very regal.
Name: Acrocanthosaurus atokensis
Meaning: high-spined reptile from Atoka [County, Oklahoma]
Time: Early Cretaceous, c 112 million years ago
Place: Texas, Oklahoma, and probably elsewhere in the US
Size: up to 11.5 metres (37.7) long, probably between 5.7-7.3 tonnes (6.3-8 tonnes)
Type of Dinosaur: carcharodontosaurid allosauroid ('landshark' predatory dinosaur)

You may remember seeing photos of this dinosaur's skeleton here on the blog not too long ago. I decided to do a restoration of it, as it's among my favourite dinosaurs. Acrocanthosaurus must have been a truly incredible animal to behold in life; its high spines would have given it a deep body profile, and its large, sleekly sloped head would've made an impressive display structure too. I didn't want to make it too adorned, as it is essentially an active pursuit predator (albeit a rather slow one) that would have been actively trailing and attacking huge sauropods, as shown by footprint evidence.

10 November 2016

Dinovember 2016, Day 10

Pompadours have been popular for a very long time. 
Name: Lambeosaurus magnicristatus
Meaning: [palaeontologist Lawrence] Lambe's reptile with a great crest
Time: Late Cretaceous, c 74.8 million years ago
Place: Alberta and possibly Montana
Size: around 9 metres (29.5 feet) long
Type of Dinosaur: lambeosaurin lambeosaurine (helmeted hollow-crested duckbill dinosaur)

The lambeosaurines are duckbill dinosaurs known for their elaborate headgear. These plant-eating dinosaurs sported large, hollow crests that would have been flashy visual signals and may also have aided them in enhancing vocalisations by acting as a resonating chamber. Lambeosaurus magnicristatus has one of the biggest crests in the group, a huge, forward-angled pompadour-like structure. This species is known from fewer remains than some of its close cousins, which seem to show potential male/female dimorphism in crest shape and size; perhaps Lambeosaurus magnicristatus did too.

09 November 2016

Dinovember 2016, Day 9

Sauropods relax and get cleaned up a bit, too.
Name: Patagosaurus faraisi
Meaning: [owner of the land where it was found, Ricardo] Farais's Patagonian reptile
Time: Middle Jurassic, c 165 million years ago
Place: Patagonia
Size: 15-16.5 metres (49-54 feet) long, 7.8-9.4 tonnes (8.6-10.4 tons)
Type of Dinosaur: cetiosaurid sauropod [primitive giant long-necked dinosaur]

Here, an adult and juvenile of the long-necked sauropod dinosaur Patagosaurus do something you don't see sauropods do often in palaeoart: sit down and relax. While resting by a tree on a hill, the giants are visited by little heterodontosaurs called Manidens - small, fuzzy omnivorous dinosaurs with beaks and procumbent tusks. I've imagined a scenario here that this is a sort of cleaning station where the large dinosaurs can come and rest while the small heterodontosaurs pick away parasites, flakes of sloughing skin and scales, and such.

Heck, let's give the little guys a profile too:

Name: Manidens condorensis
Meaning: hand-tooth from Cerro Cóndor [in reference to the shape of its back teeth and the village near its discovery site]
Time: Middle Jurassic, c 165 million years ago
Place: Patagonia
Size: 60-70 centimetres (23.6-27.6 inches) long
Type of Dinosaur: heterodontosaurid [tusked beaked dinosaur]

Technically, I may have fudged this one a bit. Manidens and Patagosaurus are from the same geologic formation but Manidens might be from a layer a couple of million years older than Patagosaurus. As far as I know, the dates for their formation are a bit uncertain so I'm not too concerned with drawing them as contemporaries. Certainly they would have had related animals coexisting if nothing else.

08 November 2016

Dinovember 2016, Day 8

Poor Prenocephale can't actually see why he has such a headache. 
Name: Prenocephale prenes
Meaning: inclined sloping head
Time: Late Cretaceous, c 72 million years ago
Place: Mongolia
Size: 2.2-2.4 metres (7.2-7.9 feet) long
Type of Dinosaur: pachycephalosaur (bonehead plant-eater)

Prenocephale is one of the better-known members of the bonehead dinosaur group. The thickened domes of bone on top of these dinosaurs' heads has been a puzzle. Initially, they were thought to be for headbutting each other but this idea fell out of favour. Research in recent years, like this study by Joseph E Peterson and colleagues, suggests that the number of injuries observed on boneheads' domes supports their use in head-to-head combat. Additionally, the domes were probably coated in a keratin layer. This poor Prenocephale has taken a bad hit at just the wrong angle, leaving him with nasty lesions developing on his injured dome.

07 November 2016

Dinovember 2016, Day 7

Ornitholestes doesn't mind you noticing his baldness. 
Name: Ornitholestes hermanni
Meaning: [AMNH fossil preparator Adam] Hermann's bird robber
Time: Late Jurassic, c 154 million years ago
Place: Wyoming
Size: about 2 metres (6.6 feet) long and 15 kilograms (33 pounds)
Type of Dinosaur: tyrannoraptoran coelurosaur (birdlike predatory dinosaur)

Despite being one of the better-known coelurosaurs and small dinosaurs of the Jurassic Period, Ornitholestes is only known from one specimen, unearthed in 1900 at Bone Cabin Quarry in Wyoming - the site where the Diplodocus limbs and Dryosaurus skeleton on display at the Beneski Museum are from. In fact, Amherst College's very own bone bloodhound, Frederic Brewster Loomis, was a member of the team that excavated the single skeleton during his days working for the American Museum of Natural History.

The relationships of Ornitholestes have long been contentious, but it's definitely a bird-like coelurosaur, and thus would've had some sort of feathery covering. I've given this one a naked, bare-skinned head, both a nod to Gregory S Paul's 1988 Predatory Dinosaurs of the World restoration and just a look that I like to use a lot. The rest of the body is covered in loose feathers, with longer ones forming a sort of ruff at the base of the neck. And no, it doesn't have a little crest on its nose - that common element of Ornitholestes reconstructions was based on crushing of the skull during fossilisation.

06 November 2016

Dinovember 2016, Day 6

Barosaurus, small and large. Also, sauropods: it takes a special kind
of organism to make an individual the length of two buses 'small.'
Name: Barosaurus lentus
Meaning: slow heavy reptile
Time: Late Jurassic, c 150 million years ago
Place: South Dakota, Utah, Colorado
Size: about 25 metres (82 feet) long and 13 tonnes (14.3 tons) typically; some (presumably) very old individuals appear to have reached sizes of approximately 50 metres (164 feet) long and 105 tonnes (116 tons)
Type of Dinosaur: diplodocine diplodocid (slender-built whip-tailed long-necked dinosaur)

Barosaurus is often forgotten amongst the Morrison Formation sauropods, losing out to more famous and familiar contemporaries Diplodocus, Brontosaurus, Apatosaurus, Camarasaurus, and Brachiosaurus. The impressive rearing specimen at the American Museum of Natural History is probably Barosaurus's most iconic - which isn't bad at all; many would say the AMNH display is the most incredible fossil mount in the world. Other than that, though, Barosaurus just doesn't have the presence some of its neighbour sauropods do.

However, there's the 'little' matter of BYU 9024 to consider... this specimen, a neck vertebra, comes from the Dry Mesa Quarry in Colorado and, at 138 centimetres (54.3 inches) long, is the largest vertebra known from any animal, ever. Initially identified as coming from a Supersaurus specimen, the SV-POWsketeers Mike Taylor and Matt Wedel have recently proposed that this bone is from Barosaurus - it matches the existing specimens of Barosaurus perfectly, except in size. This bone would come from an animal roughly twice as long as the AMNH mount, and probably around eight times as massive. In the picture above, the animal in the foreground is an AMNH-style, 25-metre Barosaurus; the looming monstrosity in the background is a BYU-style, 50-metre individual... and I'm not actually sure that I made it big enough.

05 November 2016

Dinovember 2016, Day 5

How many species do you see here, one or two? And are they Triceratops or not?
Name: Torosaurus latus
Meaning: the intended etymology is not totally clear, but it probably means 'wide perforated reptile', in reference to the broad frill and large openings in it; Torosaurus does NOT mean, as is often translated, 'bull reptile'
Time: Late Cretaceous, c 66 million years ago
Place: Western US and Saskatchewan
Size: about 7-9 metres (23-29.5 feet) long; weighed probably 8-13 tonnes (8.8-14.3 tons)
Type of Dinosaur: triceratopsin chasmosaurine (advanced three-horned 'long-frilled' horned dinosaur)

You may be familiar with Torosaurus because of their role in the famous BBC speculative documentary Walking With Dinosaurs in the episode that focused on the extinction of the nonavian dinosaurs (although Torosaurus seem to have already disappeared shortly before the final extinction), or more likely because of the debate over the last few years as to whether Torosaurus are a distinct animal or just the fully-mature form of Triceratops, and the absolutely awful pop-science 'journalism' that blatantly misleads with clickbaity headlines and shows a profound lack of even attempting to understand questions of classification associated with that debate.

While there's too much to say about that for me to cover it here, I'll just say the evidence really seems to be on the side of 'Torosaurus are their own unique taxon, but are closely related to Triceratops,' rather than 'Torosaurus are just old adult Triceratops' - as I said, there's a lot involved here and if you want to know more, look it up! There's a lot to read about it.

In this drawing, I feature two Torosaurus, and you can see that even within Torosaurus, classification could be questionable. Notice the differences between these individuals; the one at the front is based on ANSP 15192 while the bigger one at the back is based on the huge Museum of the Rockies specimens. The horns are shaped considerably differently, especially the nose horn - pointy and forward-angled in ANSP 15192, as opposed to a massive, low, blunted boss on the MOR skulls. Details of the brow horns, frill, and snout differ too, and I've heard that despite their size the MOR Torosaurus show signs of still having a fair bit of growing up to do. Even though it's well known that details like horn and frill shape can vary a lot between individual horned dinosaurs, something about the MOR specimens in comparison with many other Torosaurus latus makes me think we might be looking at a two different species here.

Anyway, this has gone on long enough for what is supposed to be a quick picture-led post. tl;dr: Torosaurus probably aren't the same as Triceratops, and some of the specimens called Torosaurus latus might be something else.

Come back tomorrow for... SAUROPODS! FINALLY!

04 November 2016

Dinovember 2016, Day 4

Leaping Laelaps, 2016 edition.
Name: Dryptosaurus aquilunguis
Meaning: eagle-clawed tearing reptile
Time: Late Cretaceous, c 67 million years ago
Place: New Jersey, possibly North Carolina and elsewhere in the Eastern US
Size: uncertain, but probably around 7.5 metres (25 feet) long
Type of Dinosaur: mysterious tyrannosauroid (tyrant dinosaur) - perhaps an alioramin tyrannosaurine (slender-snouted advanced tyrant dinosaur)

Dryptosaurus - or as it was called at the time, Laelaps, a wonderful name from a mythological hound that was sadly found to be preoccupied by a mite - was one of the first nonavian theropod dinosaurs known to science. In 1896, Charles R Knight, maybe the greatest palaeoartist of them all, painted an iconic image called Leaping Laelaps in which a pair of these animals duke it out - it was one of the first images to portray dinosaurs as the dynamic, active creatures they truly were rather than as dull sluggards, and this painting remains breathtakingly beautiful and exciting even today.

Of course, knowledge of dinosaurs has progressed a lot since 1896. I wanted to revisit Leaping Laelaps and try my hand at restoring it now. Dryptosaurus remains a painfully mysterious dinosaur but evidence points to it being some sort of tyrannosauroid, and an analysis from early this year suggests it may be an alioramin - part of a group of tyrants so far exclusive to Mongolia and China, and known for their slender build and long, narrow skulls with small hornlets along the snout. Not only would Dryptosaurus be geographically unusual if it is an alioramin, what's known of its anatomy is odd too - it has very large, well-developed hand claws, whereas most advanced tyrants were reducing their arms significantly. Certainly an odd duck, Dryptosaurus, and I don't think we can be confident of much until we find more fossils of it - but I've restored it here as a North American alioramin with some serious fingers, while trying to keep the poses faithful to the Knightian original.

There's lots more to say about Dryptosaurus and the dinosaurs of Eastern North America, but that's for another time.

03 November 2016

Dinovember 2016, Day 3

A Trinisaura stands tall to survey the winter
wonderland of Antarctica's long, cold night.
Name: Trinisaura santamartaensis
Meaning: Trinidad's reptile from Santa Marta [after geologist Trinidad Diaz and the Santa Marta Cove site where it was discovered]
Time: Late Cretaceous, c 72 million years ago
Place: James Ross Island, Antartica
Size: about 1.5 metres (4.9 feet) long, though the known specimen is a subadult
Type of Dinosaur: elasmarian iguanodont (Patagonian-Antarctic long-legged beaked dinosaur)

Trinisaura is one of only a handful of dinosaurs known from Antarctica. While there weren't polar ice caps in the Age of Reptiles, wintertime would have been long, dark, and bitterly cold for months on end. Trinisaura may have had fuzzy feathers to insulate it among the snow and ice.

This dinosaur is part of a group of iguanodont ornithopods, advanced beaked herbivores, that is so far only known from Patagonia and Antarctica, called the elasmarians. The advanced elasmarian Talenkauen, related to Trinisaura, has a long body, long arms and legs, a long neck, and a surprisingly small skull. Since Trinisaura is only known from a partial skeleton, I used Talenkauen as a guide, though I made the neck a little shorter and head a little bigger - and being thoroughly enfluffened changes the neck's profile considerably!

02 November 2016

Dinovember 2016, Day 2

Don't let the nubby arms fool you, abelisaurs are all business.
Name: Pycnonemosaurus nevesi
Meaning: Neves's thick forest reptile [after the Brazilian state of Mato Grosso, 'thick forest', where it was found]
Time: Late Cretaceous, c 70 million years ago
Place: Southwest Brazil
Size: about 8.6-9.1 metres (28-30 feet) long
Type of Dinosaur: brachyrostran abelisaurid (blunt-faced, stump-armed predatory dinosaur)

The abelisaurs were one of the dominant group of predators on the southern continents during the Cretaceous Period. Many types of abelisaurs are known, mainly from only partial remains, so estimating the body size of these animals has been contentious. A study from this year used methods consistent across all abelisaurs to estimate size, and the results found that Pycnonemosaurus has claimed the crown as the biggest of these southern killers yet known.

Abelisaurs have famously stumpy, practically vestigial arms - that could be rotated totally at the shoulder, like our own arms. It seems that these reduced limbs could have functioned as display devices, which is why I applied a bold tissue fan to the arm-nubs of the king of the abelisaurs in the portrait above.

01 November 2016

Dinovember 2016, Day 1

This year for Dinovember, I thought instead of trying (and inevitably horribly postponing) a few lengthy round-up posts, I would just do a quick post every day with that day's drawing. Here, naturally, is the first one. 

Alcovasaurus longispinus really lives up to the name 'longispinus'! 
Name: Alcovasaurus longispinus
Meaning: long-spined Alcova reptile [after the quarry where it was found]
Time: Late Jurassic, c 150 million years ago
Place: Wyoming
Size: probably between 5.5-6.5 metres (18-21 feet) long and 2.5-3.5 tonnes (2.8-3.9 tons)
Type of Dinosaur: stegosaurid (plated dinosaur) 

Originally described as a species of Stegosaurus in the early 20th century, in 2016 this dinosaur was given the new genus name Alcovasaurus. It had very long spikes on its tail, one of which was estimated at 99 centimetres (39 inches) long - and this is just the bone core, in life it would've had keratin sheaths that might have extended the length by 30-50%. The base of an even larger spike has also been referred to Alcovasaurus

The shape, size, and arrangement of its plates is not known. I based them loosely on Stegosaurus