Author Topic: Halbred's Paleo-News Thread (Read 195495 times)

ShyGuy · « **Reply #50 on:** October 17, 2009, 10:28:32 PM »

I shot those things in Deus Ex. Greezles, I think they're called.

Halbred · « **Reply #51 on:** October 18, 2009, 06:47:02 PM »

Yes, Stratos. Three (extinct) genera with four wings: Microraptor, Anchiornis, and Pedopenna. The second pair of wings developed on the legs, but of course they couldn't "flap" their legs.

Stratos · « **Reply #52 on:** October 19, 2009, 02:57:49 AM »

So where did the leg-wings come from? Was it just a transitional thing as a number of those dinosaurs started to grow feathers/wings?

Halbred · « **Reply #53 on:** October 19, 2009, 01:07:37 PM »

Well, you see a similar thing today in many hawks and falcons, and even owls: vaned feathers on the legs. These basal paravians kind of went nuts with it though. Forewings (that is, flight feathers on the arms) were probably already present and may go as far back as the base of the Maniraptora. Leg feathers, though, seem to be a synapomorphy of Paraves, but was quickly lost in all three paravian families.

Stratos · « **Reply #54 on:** October 19, 2009, 02:58:40 PM »

I see. Interesting how those modern birds still have the feathers on the legs.

Why did the wings appear in the first place if they then disappeared quickly after the Paraves? Did they serve a purpose or was it just a side affect of the growing of feathers in general?

Now you have me searching through Wikipedia looking at those dinosaurs.

I didn't know that Velociraptors had a full coat of feathers. I thought it was more superficial and sparse.

Halbred · « **Reply #55 on:** October 19, 2009, 07:20:52 PM »

Nope! There's at least one Velociraptor ulna with quill nobs, which suggests a dense coat of feathers. Non-avian maniraptors were probably just as feathery as their avian counterparts, but with shorter arms and bigger claws.

Here's a wonderful illustration of that: http://australianmuseum.net.au/image/Deinonychus-attacking/

As for the hindwings, it's not clear why they arose in the first place, but they were probably a big help before true flight arose: they'd help control descent and glide speed initially, but advances in the flap mechanics of the forelimbs would have left them eventually unecessary.

Note also that two of the groups with hindwings--troodontids and dromaeosaurs--eventually became cursorial, losing all aerial capabilities. From flighted ancestors, they became basically Cretaceous ostriches. Well, big scary predatory ostriches.

ShyGuy · « **Reply #56 on:** October 19, 2009, 08:22:33 PM »

What if all the dinos had feathers? Then they would be birds with teeth.

Stratos · « **Reply #57 on:** October 20, 2009, 04:02:19 AM »

Wild Turkeys with teeth would be scary. I read about a guy who got attacked by a flock of wild turkeys once. Those things are huge! Imagine feathery dinosaurs chasing you today.

So where do Pteranadons (sp?) fall into this? Were they before these guys or a different group entirely?

Halbred · « **Reply #58 on:** October 20, 2009, 01:46:18 PM »

First, at ShyGuy: It's entirely possible that feathers, or feather-like structures, were basal to Dinosauria. Until earlier this year, feathers were restricted (in terms of fossil evidence) to higher theropods--carnivorous dinosaurs closely related to birds (and birds themselves). No feathers allosaurs, dilophosaurus, spinosaurs, etc.

HOWEVER, a cute little ornithischian named Tianyulong was found in China that may rewrite our assumptions about who had feathers and who didn't. Dinosauria is split into two groups: Saurischians (theropods and sauropods) and Ornithischians (horned dinosaurs, armored dinosaurs, and duckbills). Tianyulong is a basal ornithischian.

This SUGGESTS that the common ancestor of Ornithischia and Saurischia (that would be sometime in the early Late Triassic) had some kind of primitive feather covering. We'll need LOTS more fossils to be sure. It's also possible that feather-like structures arose independantly in both groups.

On to Stratos: Pteranodon and its cousins, the pterosaurs, are an entirely different group. It's not even clear where they fall on the diapsid family tree, but they're probably close to (but farther down than) the Dinosauria.

Halbred · « **Reply #59 on:** October 22, 2009, 04:58:21 PM »

New heterodontosaur was described yesterday in the Proceedings of the Royal Society B. Get it while it's still open access! It's an archaic member of the group that's from the Early Cretaceous, so it would've been a "living fossil" in its own time.

It's name is Fruitadens haagarorum. Unlike most other heterodontosaurs, it does not have an upper caniniform tooth, though the lower one fits into a handy diastema between the premaxilla and maxilla. It is the first North American representative of the group, and was probably a generalist feeder, possibly even an omnivore. It was highly cursorial, given the coelophysoid-shaped femur, and its hands were surprisingly raptorial. It may have hunted as much small game as it ate plants.

This generalist diet likely contributed to the longevity of the group. The earliest heterodontosaurs are from the Late Triassic.

Stratos · « **Reply #60 on:** October 23, 2009, 03:33:01 AM »

Are there pics?

that Baby guy · « **Reply #61 on:** October 23, 2009, 03:54:22 AM »

I'm thinking about writing a fake review of this dinosaur. I just wonder if seeing pics would ruin said review...?

Halbred · « **Reply #62 on:** October 23, 2009, 02:10:31 PM »

Here are a few pictures, not from the paper itself.

Model of the little bugger, life-sized:
http://www.dawn.com/wps/wcm/connect/55bf49804003fbea96479eacdf80898b/smallest-dino-ap-608.jpg?MOD=AJPERES

A fragment of the dentary:
http://www.nhm.ac.uk/resources-rx/images/fruitadens-jaw-200-45203-1.jpg

Size comparison to your feet:
http://www.nhm.ac.uk/resources-rx/images/fruitadens-490_45202_2.jpg

vudu · « **Reply #63 on:** October 23, 2009, 02:19:05 PM »

That's not a dinosaur--that's a house pet.

NinGurl69 *huggles · « **Reply #64 on:** October 23, 2009, 02:23:45 PM »

That, my friends, is a Turkey.

When the Cave Men celebrated Thanksgiving, that's what they cooked.

Stratos · « **Reply #65 on:** October 23, 2009, 05:19:42 PM »

Quote from: NinGurl69 *huggles on October 23, 2009, 02:23:45 PM

That, my friends, is a Turkey.

When the Cave Men celebrated Thanksgiving, that's what they cooked.

So was it easy enough for a cave man to do? Call Geico.

Quote from: Halbred on October 23, 2009, 02:10:31 PM

Here are a few pictures, not from the paper itself.

Model of the little bugger, life-sized:
http://www.dawn.com/wps/wcm/connect/55bf49804003fbea96479eacdf80898b/smallest-dino-ap-608.jpg?MOD=AJPERES

This picture is titled 'smallest-dino'. Is it really the smallest so far? I thought there were a few smaller ones.

Halbred · « **Reply #66 on:** October 23, 2009, 05:30:15 PM »

There are. Fruitadens is the smallest known fully-grown ornithischian dinosaur. There are smaller adult theropods (Microraptor, Hespernychus.

that Baby guy · « **Reply #67 on:** October 23, 2009, 06:18:07 PM »

Where are the feathers?

Halbred · « **Reply #68 on:** October 23, 2009, 07:41:37 PM »

Feathers are on theropods, maybe not ornithischians. The only two ornithischians discovered with quill-like integumentary structures are Psittacosaurus and Tianyulong. They are shaped more like thin porcupine quills than feathers. There's certainly no branching structure.

However, being a heterodontosaur, Fruitadens is closely related to Tianyulong, so some sort of integument would be perfectly acceptable in any life restoration. Paleo-artists are still getting used to drawing their ornthischians with integument, though. Give it time!

BlackNMild2k1 · « **Reply #69 on:** October 28, 2009, 03:57:27 AM »

Because I thought you might enjoy this

Halbred · « **Reply #70 on:** October 28, 2009, 01:11:47 PM »

Looks more like Carnotaurus!

But yeah, I love it! :-D

Halbred · « **Reply #71 on:** October 28, 2009, 05:56:43 PM »

You can go ahead and prune two names off the pachycephalosaur family tree--it turns out that Dracorex hogwartsia and Stygimoloch spinfer represent the juvenile and subadult (respectively) of Pachycephalosaurus wyomingensis.

Horner and Goodwin came to this conclusion after realizing that all three genera had horns in the same places, and that the bone histeology of Dracorex conforms to that of a juvenile animal, while Styigmoloch is more or less a "teenager." Taken together with the fact that all three are known from the same formation and time (Hell Creek), and you've got a growth series!

So the short version: What were once three genera have been shrunk down to ONE.

That has implications for dinosaur diversity at the end of the Cretaceous in the Hell Creek formation. Nanotyrannus is probably a juvenile Tyrannosaurus, too, and at SVP this year, one presenter suggested that Torosaurus represents an old growth stage of Triceratops. If all this is true, then dinosaur diversity plummeted at the end of the Cretaceous in North America, well before the comet hit.

But more interestingly, it shows that pachycephalosaur skulls were extensively remodeled during growth, just like ceratopsians. As the two groups are usually united in a monophyletic Marginocephalia, this kind of transformative growth could be a synapomorphy of that group.

It's a brave new world. Download the paper FREE from here:

http://www.plosone.org/article/info:doi/10.1371/journal.pone.0007626

that Baby guy · « **Reply #72 on:** October 28, 2009, 06:01:57 PM »

What about the feathers?

Halbred · « **Reply #73 on:** October 28, 2009, 06:24:52 PM »

...What about the feathers?

that Baby guy · « **Reply #74 on:** October 28, 2009, 06:29:16 PM »

I dunno. Feathers seemed like a cheap maneuver to reinvigorate the general public's interest in dinosaurs. They didn't realize that dinosaurs don't need feathers to be cool, and instead, it just makes them look like they're at a Shakespearean costume ball.

So far, feathers haven't been mentioned, so I'm trying to make sure this dinosaur is awesome and not some kind of nancy-boy dinosaur for widespread disinterest.

News:

Author Topic: Halbred's Paleo-News Thread (Read 195495 times)