ewilloughby:

This is a speculative reconstruction of a subadult Deinonychus displaying semi-arboreal characteristics. It’s based on the tenuous assumption that the type specimen (YPM 5205) represents an immature animal, as compared to later specimens with slightly different morphological characteristics, most notably the Harvard specimen (MCZ 4371) described in 1976. Ostrom noted in the description for this newer specimen that one of the major differences between this and the type is the angle of curvature for the second pedal claw: the newer specimen had a much straighter sickle claw, while the original was very strongly curved. However, he had no opinion at the time on whether this difference in morphology represented individual, ontogenetic, or sexual variation.(1)
In 2006, Parsons & Parsons demonstrated unequivocally that the Harvard specimen is a sexually mature adult, and identified some unique adult characters associated with this and other mature adult Deinonychus specimens.(2) Further study by the same authors in 2009 tentatively indicates that the type specimen—a possible subadult—may be associated with arboreal characteristics. Adult specimens are also found to have proportionally shorter arms, leaving room to speculate whether the longer arms of subadults could have been a semi-volant adaptation involved in some incipient gliding (or, perhaps more accurate for an animal that size, “descent-slowing”) capabilities. The more strongly recurved second pedal claw is implicated in climbing, and its lateral compression and inner arc are compared in this paper to the same ungual in Melanerpes, the red-headed woodpecker (a highly scansorial modern bird).(3)
Behavior rarely fossilizes, and the idea that immature Deinonychus occupied a partially arboreal niche is still highly speculative, especially given that few modern archosaurs possess markedly different ecologies at different ontogenic stages. And while I don’t usually support copying extant birds this precisely for serious paleoart, it proved to be an excellent practice piece to flesh out a highly speculative idea.
This piece is based directly on an excellent photograph by my most admired living scientist, experimental psychologist Steven Pinker, who was kind enough to grant me permission to do so. Pinker is a world-renowned cognitive scientist as well as a talented photographer, and you can check out more of his better angles of our nature on his website at stevepinker.com.
It’s interesting to note that of all known specimens of deinonychosaurs, a sizable percentage of them represent juveniles or subadults, animals that lived very brief lives before succumbing to nature’s indifference. For the life of a Deinonychus was surely solitary, poor, nasty, brutish and short.
—
1. Ostrom, J. H. (1976). “On a new specimen of the Lower Cretaceous theropod dinosaur Deinonychus antirrhopus”. Breviora 439: 1–21.2. Parsons, W. L.; Parsons, K. M. (2006). “Morphology and size of an adult specimen of Deinonychus antirrhopus, (Saurischia, Theropoda)”. Journal of Vertebrate Paleontology 26 (3 sup.): 109A.3. Parsons, W. L.; Parsons, K. M. (2009). “Further descriptions of the osteology of Deinonychus antirrhopus (Saurischia, Theropoda)”. Bulletin of the Buffalo Society of Natural Sciences 38: 43–54.

ewilloughby:

This is a speculative reconstruction of a subadult Deinonychus displaying semi-arboreal characteristics. It’s based on the tenuous assumption that the type specimen (YPM 5205) represents an immature animal, as compared to later specimens with slightly different morphological characteristics, most notably the Harvard specimen (MCZ 4371) described in 1976. Ostrom noted in the description for this newer specimen that one of the major differences between this and the type is the angle of curvature for the second pedal claw: the newer specimen had a much straighter sickle claw, while the original was very strongly curved. However, he had no opinion at the time on whether this difference in morphology represented individual, ontogenetic, or sexual variation.(1)

In 2006, Parsons & Parsons demonstrated unequivocally that the Harvard specimen is a sexually mature adult, and identified some unique adult characters associated with this and other mature adult Deinonychus specimens.(2) Further study by the same authors in 2009 tentatively indicates that the type specimen—a possible subadult—may be associated with arboreal characteristics. Adult specimens are also found to have proportionally shorter arms, leaving room to speculate whether the longer arms of subadults could have been a semi-volant adaptation involved in some incipient gliding (or, perhaps more accurate for an animal that size, “descent-slowing”) capabilities. The more strongly recurved second pedal claw is implicated in climbing, and its lateral compression and inner arc are compared in this paper to the same ungual in Melanerpes, the red-headed woodpecker (a highly scansorial modern bird).(3)

Behavior rarely fossilizes, and the idea that immature Deinonychus occupied a partially arboreal niche is still highly speculative, especially given that few modern archosaurs possess markedly different ecologies at different ontogenic stages. And while I don’t usually support copying extant birds this precisely for serious paleoart, it proved to be an excellent practice piece to flesh out a highly speculative idea.

This piece is based directly on an excellent photograph by my most admired living scientist, experimental psychologist Steven Pinker, who was kind enough to grant me permission to do so. Pinker is a world-renowned cognitive scientist as well as a talented photographer, and you can check out more of his better angles of our nature on his website at stevepinker.com.

It’s interesting to note that of all known specimens of deinonychosaurs, a sizable percentage of them represent juveniles or subadults, animals that lived very brief lives before succumbing to nature’s indifference. For the life of a Deinonychus was surely solitary, poor, nasty, brutish and short.

1. Ostrom, J. H. (1976). “On a new specimen of the Lower Cretaceous theropod dinosaur Deinonychus antirrhopus”. Breviora 439: 1–21.

2. Parsons, W. L.; Parsons, K. M. (2006). “Morphology and size of an adult specimen of Deinonychus antirrhopus, (Saurischia, Theropoda)”. Journal of Vertebrate Paleontology 26 (3 sup.): 109A.

3. Parsons, W. L.; Parsons, K. M. (2009). “Further descriptions of the osteology of Deinonychus antirrhopus (Saurischia, Theropoda)”. Bulletin of the Buffalo Society of Natural Sciences 38: 43–54.

openfigs:

Figure 8. Ventral view of Deinonychus foot (MOR 747) in flexion.
Citation: Fowler DW, Freedman EA, Scannella JB, Kambic RE (2011) The Predatory Ecology of Deinonychus and the Origin of Flapping in Birds. PLoS ONE 6(12): e28964. doi:10.1371/journal.pone.0028964

openfigs:

Figure 8. Ventral view of Deinonychus foot (MOR 747) in flexion.

Citation: Fowler DW, Freedman EA, Scannella JB, Kambic RE (2011) The Predatory Ecology of Deinonychus and the Origin of Flapping in Birds. PLoS ONE 6(12): e28964. doi:10.1371/journal.pone.0028964

transhamlet:

quick utahraptor doodle, scanner still not ct’d

Rather, generic eudromaeosaur.

transhamlet:

quick utahraptor doodle, scanner still not ct’d

Rather, generic eudromaeosaur.

palaeoplushies:

My Kickstarter Campaign for the plushie velociraptor is live! Click here!

Here’s your chance to get your hands on some Velociraptor-themed goodies!

I’m so excited! Thanks everyone!

Please signal-boost if you like!

I implore everyone to support her Kickstarter! She worked hard on her stuff and the results are amazing. Spread the word and/or get yourself a fluffy V.mongoliensis!

palaeoplushies:

Things have been rather quiet from Palaeoplushie land… but it’s the quiet before the storm.
Here’s some previews of the upcoming kickstarter! Some sticker art, a mock-up of a enamel pin badge and the star attraction: The plushie velociraptor itself!

(Also, a massive thanks to Scott Hartman for the skeletal that the top image and subsequent designs were based off of! http://www.skeletaldrawing.com/)

Reblog to help a friend, go Bex!

assuming-dinosaur:

A̷ͧ͛̏͘L̵ͤ̇͋̅̃̚͘L͊̈ͪ̋̒̽̅͛҉͘͝ ̇͊̔̐ͨ̊͗͞͏H̛̛ͮ͆́Aͨ̐͋͑Ḯ̈́̌͂̍L̸͗ͤ͢ ̛̂͛ͣ͊̑̑҉Ť͐̓̈́ͩ̽͡Ḧ̵́̄͂͗E̢̓̎ ́̑̋̆̆͟͞M̷̽̈͌ͣI̧ͪͯ͋͑͏Ḡ͗͒͂̄̕H̷̃ͦ̇͘͘T̨̽ͨ̈ͦ̚̚Ȳ̈̒̓ͥ̚̕ ̷̨̿ͨ̈́ͭ͜Gͧ͜L̸̇ͦͫͬ͝͡O͐ͦ̈́̀͘͢W̢̿ͯ́ ̡́̓̒ͬ̔̾ͩͨ͜͠R̷̨ͮ̾̀͌ͯ̾ͯͬA͆ͫ̑ͩP͗͏T̨̄͐̓ͥ͋͒ͦ͢O̓̇̐ͦ̿͗ͤͤ͏̛Řͤͧ̏̔͌ͬ̍͜

assuming-dinosaur:

A̷ͧ͛̏͘L̵ͤ̇͋̅̃̚͘L͊̈ͪ̋̒̽̅͛҉͘͝ ̇͊̔̐ͨ̊͗͞͏H̛̛ͮ͆́Aͨ̐͋͑Ḯ̈́̌͂̍L̸͗ͤ͢ ̛̂͛ͣ͊̑̑҉Ť͐̓̈́ͩ̽͡Ḧ̵́̄͂͗E̢̓̎ ́̑̋̆̆͟͞M̷̽̈͌ͣI̧ͪͯ͋͑͏Ḡ͗͒͂̄̕H̷̃ͦ̇͘͘T̨̽ͨ̈ͦ̚̚Ȳ̈̒̓ͥ̚̕ ̷̨̿ͨ̈́ͭ͜Gͧ͜L̸̇ͦͫͬ͝͡O͐ͦ̈́̀͘͢W̢̿ͯ́ ̡́̓̒ͬ̔̾ͩͨ͜͠R̷̨ͮ̾̀͌ͯ̾ͯͬA͆ͫ̑ͩP͗͏T̨̄͐̓ͥ͋͒ͦ͢O̓̇̐ͦ̿͗ͤͤ͏̛Řͤͧ̏̔͌ͬ̍͜

(Source: artisticthingem)

tragopan:

A sketch I drew a while ago, but it was just laying around on my hard drive being useless so I decided to upload it here. Why not?
A medium-size deinonychosaur watches from behind a log as a Changyuraptor hides its chicks under its wings.

tragopan:

A sketch I drew a while ago, but it was just laying around on my hard drive being useless so I decided to upload it here. Why not?

A medium-size deinonychosaur watches from behind a log as a Changyuraptor hides its chicks under its wings.

ewilloughby:

Diagnostic anatomical reconstruction of Deinonychus antirrhopus, intended loosely for Wikipedia but also as an experimental piece to show pretty much exactly how I believe this animal looked in life.
This was largely inspired by an interesting Facebook discussion with paleoartist Julius Csotonyi about arm-folding in paravian dinosaurs. It occurred to me that people seldom reconstruct paravians, particularly dromaeosaurs, with their arms folded in a reasonable and accurate way. Julius made the fair the point that these animals probably didn’t carry their arms out in front of the body, as is so often depicted (in skeletals and otherwise — it makes sense in skeletals, to adequately show the hand and arm anatomy), because such an awkward orientation would leave the hand and arm feathers open to damage and breakage. But they also can’t fold them tightly against the breast or back like birds do, because they lack the mobility to do so.
So how did Deinonychus normally carry its arms? Senter’s 2006 paper on forelimb function in Deinonychus and Bambiraptor shows that the humerus couldn’t rotate much past the horizontal with respect to the scapula. In addition, Sullivan et al. 2010 — winningly translated to layman coherency by Matt Martyniuk — shows that wrist mobility in many paravians is much less than you might expect, given their similarity to birds. The wrist of Deinonychus antirrhopus specifically would not have allowed it to bend its hands even 90° with respect to the arm!
Given these limitations, most of the flexion would have to occur at the elbow, but a fully flexed elbow would mean that the hands would be hanging below the body, not held sleek and secure alongside the body. The arm orientation in my illustration above is based on what I think is probably the perfect configuration for carrying the arms: a fully-flexed shoulder, a fully-flexed wrist, and a nearly fully-extended elbow. A few other people have drawn their dromaeosaurs with the same arm configuration, like Smnt2000 and Pilsator, so kudos to them.
Illustration based on the papers linked above as well as Scott Hartman's beautiful skeletal. Gouache on 12” x 20” hot-pressed illustration board.

ewilloughby:

Diagnostic anatomical reconstruction of Deinonychus antirrhopus, intended loosely for Wikipedia but also as an experimental piece to show pretty much exactly how I believe this animal looked in life.

This was largely inspired by an interesting Facebook discussion with paleoartist Julius Csotonyi about arm-folding in paravian dinosaurs. It occurred to me that people seldom reconstruct paravians, particularly dromaeosaurs, with their arms folded in a reasonable and accurate way. Julius made the fair the point that these animals probably didn’t carry their arms out in front of the body, as is so often depicted (in skeletals and otherwise — it makes sense in skeletals, to adequately show the hand and arm anatomy), because such an awkward orientation would leave the hand and arm feathers open to damage and breakage. But they also can’t fold them tightly against the breast or back like birds do, because they lack the mobility to do so.

So how did Deinonychus normally carry its arms? Senter’s 2006 paper on forelimb function in Deinonychus and Bambiraptor shows that the humerus couldn’t rotate much past the horizontal with respect to the scapula. In addition, Sullivan et al. 2010 — winningly translated to layman coherency by Matt Martyniuk — shows that wrist mobility in many paravians is much less than you might expect, given their similarity to birds. The wrist of Deinonychus antirrhopus specifically would not have allowed it to bend its hands even 90° with respect to the arm!

Given these limitations, most of the flexion would have to occur at the elbow, but a fully flexed elbow would mean that the hands would be hanging below the body, not held sleek and secure alongside the body. The arm orientation in my illustration above is based on what I think is probably the perfect configuration for carrying the arms: a fully-flexed shoulder, a fully-flexed wrist, and a nearly fully-extended elbow. A few other people have drawn their dromaeosaurs with the same arm configuration, like Smnt2000 and Pilsator, so kudos to them.

Illustration based on the papers linked above as well as Scott Hartman's beautiful skeletal. Gouache on 12” x 20” hot-pressed illustration board.