The Lurkdragon's Lair

Fifty percent animals, fifty percent fandom, one-hundred percent nerd.

Posts tagged predation

465 notes

rhamphotheca:

Bizarre, Prehistoric Ratfish Chomped Prey with Buzzsaw Jaws
by Brian Switek 
Helicoprion had saws for jaws. That’s really all there was to the 270 million year old ratfish’s dental cutlery. No upper teeth or anything else to slice against – just an ever-growing whorl of spiky teeth anchored to the lower jaw.
This new, definitive image of Helicoprion debuted last year thanks to the efforts of artist Ray Troll and a team of researchers led by Idaho State University paleontologist Leif Tapanila. A very special fossil – IMNH 37899 – preserved both the upper and lower jaws in a closed position, finally solving the mystery of what the ratfish’s head actually looked like. But determining the exact placement of that vexing spiral was just an initial step.
Paleontologists and artists had often supposed that Helicoprion had upper teeth to pierce slippery cephalopods and squirming fish, but the fossils Tapanila and colleagues examined showed that Helicoprion only had a buzzsaw embedded in the lower jaw. How did this long-lived and prolific genus of Permian fish eat with a saw for a jaw? …
(read more: Laelaps blog - National Geographic)
photograph by Brian Switek

rhamphotheca:

Bizarre, Prehistoric Ratfish Chomped Prey with Buzzsaw Jaws

by Brian Switek 

Helicoprion had saws for jaws. That’s really all there was to the 270 million year old ratfish’s dental cutlery. No upper teeth or anything else to slice against – just an ever-growing whorl of spiky teeth anchored to the lower jaw.

This new, definitive image of Helicoprion debuted last year thanks to the efforts of artist Ray Troll and a team of researchers led by Idaho State University paleontologist Leif Tapanila. A very special fossil – IMNH 37899 – preserved both the upper and lower jaws in a closed position, finally solving the mystery of what the ratfish’s head actually looked like. But determining the exact placement of that vexing spiral was just an initial step.

Paleontologists and artists had often supposed that Helicoprion had upper teeth to pierce slippery cephalopods and squirming fish, but the fossils Tapanila and colleagues examined showed that Helicoprion only had a buzzsaw embedded in the lower jaw. How did this long-lived and prolific genus of Permian fish eat with a saw for a jaw? …

(read more: Laelaps blog - National Geographic)

photograph by Brian Switek

Filed under heliocoprion fish prehistoric life ratfish chimera fish neato predation queue

426 notes

allosauropteryx:

dinosaurquillstudio:

miss-beasty:

dinosaurquillstudio:

I’ve always wondered why paleo artists always give theropods a crocodilian mouth, where you can see the corner of the mouth muscles. 

If you look at a crocodilian skull the back of the upper jaw moves away from bottom jaw and Pterygoid(the bone in the back of the throat) is exposed and extremely pronounced. This would show that there is a major muscle there to connect the jaws together.

Where as with birds the upper jaw comes towards the bottom jaw, thus the corner of the mouth becomes a lip, and tends to meet under the eyes. 

This is about the same for theropod dinosaurs. They always have the fenetre laterotemporale(the large hole behind the head) where a lot of the jaw muscles attach and feed behind the jugal bone and to the bottom jaw. I would expect more of a bird mouth with lips rather than a muscular pink tissue that would be showing off and more of a hidden muscle like a bird mouth.

now I could be wrong, but after working as a bird taxidermist and seeing how bird mouths work and look and after working on an alligator, i can see a major difference between the two. 

Theropod dinosaurs don’t have the massive gap between the jaws that would possibly suggest more of a reptilian/crocodilian mouth, and would seem to have more of the bird like lip. Especially considering that theropod dinosaurs are the ancestors of birds, I would expect more of this.

I’ve never been to a dinosaur museum and the ones here are only replicas(allosaurus, triceratops, and apatorsaurus) so i’m limited at what skulls i can look at in person to better exam them, and the internet is so limited as to what angles I can see these skulls and if they are replicas/sculptures, or the real deal….and I can’t rotate them to get a full 360 view of what they look like….so this is the best that I can do with the resources I have.

I did a quick sketch of a Dilophosaurus skull and a fleshed out head at the top, the rest are google images i used as examples to better explain this.

Wow, I have never observed this difference before! It looks spot on to me, very astute. It makes sense that with all their birdy traits, they’d have birdy facial structure. Lovely sketch too (:

Thank you :D

And to further add onto this, if you look at these photos below, it further shows how the muscles attach in the skull of theropods, birds, and crocodilians, to further add onto this.

Theropod muscle attachments.

Bird Muscle Attachments

and crocodilian muscle attachments

now you have a more x-ray view of the differences.

The muscles attach in a completely different way and considering crocodilians have grown on a seperate branch of evolution that of dinosaurs and birds(even though they have the gene to grow feathers). 

I wonder though if scientists have thought of this idea….I can understand with bigger theropods like tyrannosaurus or spinosaurus with having a bit of the pink muscle showing, but some bird species also somewhat show off a bit of meat in the corner of the mouth when they open them….but there would still be a closed lip gap under the eye to some extent, and not a crocodilian smile we see most of the time in paleolithic art.

as seen here….the gap would be a closed solid piece of skin.

I guess this would fall under the book “All Yesterdays” idea of a “shrunken skeleton”.

First, that bird skull isn’t from a bald eagle, it’s from a barn owl (same picture is, in fact, here on Wikipedia). I’m not sure what’s going on in the live-eagle picture, but that’s either a bad photoshop, a deformed beak, or a poor prosthetic. Actual, normal bald eagle skull and head:

Speaking as a very amateur paleontographer, I’d say it’s probably mostly one of the “artmemes” for this generation or so. Everyone “knows” that’s what dinosaurs look like because they’ve been seeing that general reconstruction since childhood in all kinds of models and artwork.

If you’re looking at birds, most raptors and passerines actually aren’t the best as the tissue that lines the corner of their mouth is essentially still beak, though it’s softer. Parrots, despite having a number of naked-faced species, are also highly modified and have, as I understand it, some unique mouth muscles.

The birds I’d recommend for dinosaurmouths are California Condors (naked skin shows underlying structures better, and they have a cheek-like extension of skin to give a more accurate cheek option for herbivores), gulls of all kinds (no gape, and are always making rude faces and trying to eat things bigger than their heads), ostriches (less derived, simple feathers on head), and galloanserans including chickens and geese (less derived, common, and have common behaviors that include a wide open beak)

bonus: never seen anyone add teeth to a tyrannosaur’s tongue, do it and see how it goes. Everyone gives dinosaurs boring crocodile tongues anyway.

I would like to add that, particularly for primitive theropods and sauropodomorphs, you should probably take a look at some non-archosaurian reptiles. Dinosaurs were not lepidosaurs or turtles, yes, but turtle beaks can give some better idea what to do with your ornithischians, and lepidosaurs are relatively conservative.

All pictures are from Wikimedia Commons (01, 2, 3, 4, 5, 6) , except the Haliaeetus skull, which is from Digimorph. Digimorph is a great source of skull images for many species, including several fossil dinosaurs and some birds, and most specimens have very useful rotating views.

(Source: dinosaurquill, via prehistoric-birds)

Filed under long posts predation dinosaurs reference birds queue

1,415 notes

rhamphotheca:

Major discovery: Wolves help trees grow, rivers flow, countless species flourish
by Michael Graham Richard
It might not seem obvious at first, but wolves can have a huge indirect effect on ecosystems. They aren’t just good for reducing deer populations and such; they fundamentally change how these herbivores behave, where they graze and which areas they avoid.
This means that trees and plants start growing again in places that were overgrazed, giving shelter to all kinds of species (songbirds, beavers, rabbits). This in turns changes how the local ecosystem works further, providing more ecological niches to more species, until after a few years the area is almost unrecognizably more alive! All this thanks to wolves, this underrated apex predator!
Check out the great video below to see the chain of events in action after wolves were reintroduced in Yellowstone after an absence of about 70 years…
(find out more: TreeHugger)

rhamphotheca:

Major discovery: Wolves help trees grow, rivers flow, countless species flourish

by Michael Graham Richard

It might not seem obvious at first, but wolves can have a huge indirect effect on ecosystems. They aren’t just good for reducing deer populations and such; they fundamentally change how these herbivores behave, where they graze and which areas they avoid.

This means that trees and plants start growing again in places that were overgrazed, giving shelter to all kinds of species (songbirds, beavers, rabbits). This in turns changes how the local ecosystem works further, providing more ecological niches to more species, until after a few years the area is almost unrecognizably more alive! All this thanks to wolves, this underrated apex predator!

Check out the great video below to see the chain of events in action after wolves were reintroduced in Yellowstone after an absence of about 70 years…

(find out more: TreeHugger)

Filed under wolves canines yellowstone queue predation