Czerkas and Feduccia disconnect birds and dinos

Figure 1. Reconstruction of Scansoriopteryx with possible feather extent by Stephen Czerkas. Good thing that second branch or telephone wire is available for balance!

Figure 1. Reconstruction of Scansoriopteryx with possible feather extent by Stephen Czerkas. Good thing that second branch or telephone wire is available for balance!

A new paper by Czerkas and Feduccia
attempts to unlink birds with dinosaurs and to link birds with some unspecified archosaur by their reexamination of Scansoriopteryx, a tiny Chinese fossil of the Jurassic. Much has already been said about this paper — all negative.

Czerkas and Feduccia report the “absence of fundamental dinosaurian characteristics,” but do not do so with phylogenetic analysis, which would have nested their study subject somewhere else that they could support, but can’t. They seem stuck in a trees-down vs. ground up battle when plenty of ground-dwelling dinosaurs seem fully capable of climbing a tree by grappling or simply by running up a vertical trunk bipedally, as some modern birds do (any Dial reference below). Their illustration (Fig. 1) seems to say that whether bird or dinosaur or non-dinosaur, Scansoriopteryx was not capable of standing balanced on its (apparently splayed?) hind limbs, despite the fact that it’s forelimbs appear poorly designed for walking. They’ve been accused of LarryMartinizing and it seems they have indeed been doing so. For those interested, Larry Martin preferred to discuss individual characters rather than suites of characters of a sort used in phylogenetic analysis.

I can’t buy into their particular heresy.
There’s no support for it. We need to see details and analyses. And they need to present their best alternative candidate among the non-dinosaurian archosaurs out there as a sister to Scansoriopteryx. 

The irony here
is that the same sort and style of argumentation is being used to support a pterosaur/archosaur connection by the same set of paleontologists who support the dino/bird connection. By that I mean, they present no archosaurian candidates that more closely match pterosaurs than our own favorites: the lepidosaur, tritosaur, fenestrasaurs.

So, if you’re a finger pointing paleontologist, be careful. Don’t fall into  that same trap.

References
Czerkas SA and Feduccia A 2014. Jurassic archosaur is a non-dinosaurian bird, Journal of OrnithologyDOI: 10.1007/s10336-014-1098-9
Dial KP, Jackson BE and Segre P 2008.  A fundamental avian wing-stroke provides a new perspective on the evolution of flight. Nature (online 23 Jan 08)
Padian K and Dial KP 2005. Could the “Four Winged” Dinosaurs Fly?  Nature: 438:E3-5.
Dial KP, Randall R and Dial TR 2006. What use is half a wing in the evolution of flapping flight? BioScience 56: 437-445.
Tobalske BW and Dial KP 2007. Aerodynamics of wing-assisted incline running. J. Exp. Biol. 210:1742-1751.
Bundle MW and Dial KP  2003. Mechanics of wing-assisted incline running.  J. Exp. Biol., 206:4553-4564.
Dial KP 2003.  Evolution of avian locomotion: Correlates of body size, reproductive biology, flight style, development and the origin of flapping flight. Auk 120:941-952.
Dial KP 2003. Wing-assisted incline running and the evolution of flight.  Science 299:402-404.
Read more at: http://phys.org/news/2014-07-declassify-dinosaurs-great-great-grandparents-birds.html#jCp

 

Archaeopteryx vs pterosaurs: speciation? or variation? Plus an interclavicle question.

I read this today on Wiki/Archaeopteryx: “Recently, it has been argued that all the specimens belong to the same species, however, significant differences exist among the specimens. In particular, the Munich, Eichstätt, Solnhofen, and Thermopolis specimens differ from the London, Berlin, and Haarlem specimens in being smaller or much larger, having different finger proportions, having more slender snouts lined with forward-pointing teeth, and possible presence of a sternum. These differences are as large as or larger than the differences seen today between adults of different bird species, however, it also is possible that these differences could be explained by different ages of the living birds.”

Figure 1. Archaeopteryx size graphic from Wikipedia.

Figure 1. Archaeopteryx size graphic from Wikipedia created by Matt Martyniuk. Very informative. Size matters!

If that is all that separates one Archaeopteryx from another, it really is time to take another look at pterosaurs.
There are so many Pterodactylus, Pteranodon, Rhamphorhynchus, Germanodactylus, Darwinopterus, etc. etc. etc. that given the same splitting/lumping parameters someone is going to have to come up with a slew of new names.

The problem is, who has the authority?
And if anyone does have the authority, who will recognize, follow and support that authority? That time may have already passed when there were fewer workers setting standards in paleontology. Back in the 1970s the work by Wellnhofer on Solnhofen pterodactyloids (1970) and non-pterodactlyloids (1975) is encyclopedic and widely cited. I’m not sure that someone else in the present day such authority because the professional vacuum that existed then is not present today.

The answer is:
A grad student for his/her PhD dissertation might have no authority, but that doesn’t matter. These least likely candidates are incredibly talented, but largely lacking in experience, which sometimes works to their advantage. And they are always looking for large projects to tackle. This task is enormous and will involve a lifetime of study and restudy. So, maybe the parameters are not narrow enough for a decent thesis.

I suppose lumpers will always fight splitters, and vice versa, like two parents trying to name one child.

>>>>>>>>>

On a side note:
Did early amniotes and their outgroups fuse the coracoid and interclavicle? I am having a difficult time locating coracoids, at the same time that the interclavicle appears to be “amply endowed,” if you know what I mean. Here’s an example in Brouffia: (Fig. 2) and Gephyrostegus (Fig. 3). Please send literature refs if you have them.

Figure 2. Brouffia. Is the coracoid fused to the over robust interclavicle, as it would seem? Lit refs please!

Figure 2. Brouffia. Is the coracoid fused to the over robust interclavicle, as it would seem? Lit refs please!

Figure 3. This Gephyrostegus interclavicle looks suspiciously tripartite. Are coracoids fused here?

Figure 3. This Gephyrostegus interclavicle looks suspiciously tripartite. Are coracoids fused here?

Tracing fossil photos goes mainstream in 2014

DGS is going mainstream
A new paper by Chiappe et al. 2014, forsakes time honored and inaccurate pencil tracings with a camera lucida (basically a prism) and goes straight to the camera, scanner and mouse in their portrayal of the new Hongshanornis specimen. This is a great example of DGS or digital graphic segregation.

Figure 1. From Chiappe et al. 2014 showing the fossil (at right) and the digital tracing (at left).

Figure 1. From Chiappe et al. 2014 showing the fossil (at right) and the digital tracing (at left). Here’s a professional paleontologist using a technique for which I was once and continue to be derided.

There is value in this technique, even when the bones are mere impressions, and the soft tissue is ephemeral, as they appear here. (Figs. 1, 2). The technique is especially helpful in two-dimensional crushed fossils, like Hongshanornis.

Figure 2. The two images of Hongshanornis superimposed to show the exactness this tracing technique produces, plus color, plus enlargements, etc. etc.

Figure 2. The two images of Hongshanornis superimposed to show the exactness this tracing technique produces, plus color, plus enlargements, etc. etc.

Many were the times
when I tried to match a published drawing with a published photo and found I had to warp or distort one or the other to make them match. A long lens from a distance at right angles to the plane of the specimen minimizes distortion and key-stoning (perspective problems). This photography technique combined with scanning such a photo and tracing it on screen with a mouse makes that problem go away.

The next step, of course, is to use the digital tracings to create a very accurate reconstruction.

References
Chiappe L, Bo Z, O’Connor J, Chunling G, Xuri W, Habib M, Marguan-Lobon J, Qingjin M and  Xiaodong C 2014. A new specimen of the Early Cretaceous birdHongshanornis longicresta: insights into the aerodynamics and diet of a basal ornithuromorphPeerJ. 2:e234; DOI 10.7717/peerj.234

wiki/Hongshanornis

Triassic? No, Eocene Bird Tracks: How to Fix a Mistake in “Nature”

The whole point of this post is to show that sometimes scientists AND referees make mistakes. This one (see below) the authors corrected themselves, likely after catching hell from colleagues for the last 11 years. The referees are probably glad to retain their anonymity.

Figure 1. Bird tracks originally considered Latest Triassic, now considered Eocene, from Argentina.

Figure 1. Bird tracks originally considered Latest Triassic, now considered Eocene, from Argentina.

It all started a decade ago
when Melchor, De Valais and Genise (2002) reported very bird-like tracks in Latest Triassic sediments in Argentina. This was deemed worthy of the academic journal Nature because, if valid, this would have pushed the origin of birds, or bird-like dinosaurs, back from the Latest Jurassic to the Latest Triassic. A very hot topic! Respected paleontologist referees gave this the green light and it was published.

However, recently this paper was retracted.

Here’s the apologetic abstract
from Melchor, De Valais and Genise (2013) 

“Bird-like tracks from northwest Argentina have been reported as being of Late Triassic age. They were attributed to an unknown group of theropods showing some avian characters. However, we believe that these tracks are of Late Eocene age on the basis of a new weighted mean 206Pb/238U date (isotope dilution–thermal ionization mass spectrometry method) on zircons from a tuff bed in the sedimentary succession containing the fossil tracks. In consequence, the mentioned tracks are assigned to birds and its occurrence matches the known fossil record of Aves.”

Hopefully apologies have been accepted worldwide.
These three “came clean” and made their mistake known and I’m sure all three will continue to make important contributions to paleontology.

Unfortunately
Some scientists do not accept apologies or corrections. Some rifle through trash for rejected ideas so they can pillory others. Some scientist can not accept their own mistakes. Some scientists reject solutions to problems by labeling them, “highly idiosyncratic (= a mode of behavior or way of thought peculiar to an individual)” just because they have new ideas not preciously considered by others. These are the scientists who are gumming up the works.

There are several papers that have been rejected by referees clinging to the status quo that solve several enigmas and clear up several mysteries using established scientific methods. Several of those rejections from referees who are “gumming up the works” provided the reason for this blog and reptileevolution.com.

References
Melchor RN, De Valais S and Genise JF 2002. Bird-like fossil footprints from the Late Triassic. Nature 417, 936–938 (2002)
Melchor RN, De Valais S and Genise JF 2013. A late Eocene date for Late Triassic bird tracks. Nature 495, E1–E2 (21 March 2013) doi:10.1038/nature11931

Something about Turkeys on Thanksgiving

Happy Thanksgiving (America).
I encourage my readers, if they have not already done so, to check out My Life as a Turkey online at PBS (Fig. 1, click here). They’re curious, affectionate, loyal and when they hit puberty all hell can break loose. They’re beset by enemies and they learn to control their enemies. They are hit with disease and they mourn their losses. Some are independent. Others, from the same brood, seek touch. Watch them learn to fly, loose their cuteness, play with the mammals and, in the end, go out on their own.

Click to go to online video at PBS/Nature. My Life as a Turkey explores the ontogeny of these little dinosaurs as thoroughly as I've ever seen.

Click to go to online video at PBS/Nature. My Life as a Turkey explores the ontogeny of these little dinosaurs as thoroughly as I’ve ever seen.

Alpine Swifts and Pterosaurs

Alpine Swift (Tachymarptis melba) on the wing for 7 months at a time! Check out that wing shape. Remind you of anything prehistoric?

Alpine Swift (Tachymarptis melba) on the wing for 7 months at a time! Check out that wing shape. Remind you of anything prehistoric?

An interesting NatGeo post on the Alpine Swift (Tachymarptis melba) and its incredible but true 7 months (200 days) on the wing (Liechti et al. 2013) raised my curiosity about what sort of wing must such a bird have?

Turns out to have a very pterosaurian wing (short chord version) in ventral view. Nat Geo reports, Their long wings make them fast and manoeuvrable, allowing them to scythe through the air in search of small insects and other “aerial plankton”.

And why do they fly continuously? Again, Liechti has speculations rather than answers. They may exploit food sources that other birds can’t touch, avoid predators by flying through the night, or stay beyond the reach of parasites like malarial mosquitoes. “These aren’t very convincing,” he admits, “but for sure, there’s a cost to staying in the air, so there must be a benefit.”

Swifts are apodids, famous for their tiny feet (they don’t perch that often). That takes us to the pterosaurs with tiny feet and spindly legs, the ornithocheirids (Fig. 2, 3).

Worth comparing for wing shape and foot size.
Evidently these large pterosaurs were likewise rarely grounded, based on their tiny feet and giant wings, especially compared to other pterosaurs.

Figure 2. The ornithocheirid pterosaur, Arthurdactylus. Note the tiny size of its feet.

Figure 2. The ornithocheirid pterosaur, Arthurdactylus. Note the tiny size of its feet and the huge wings. Like a swift, this pterosaur could have slept while on the wing. The spindly fingers were no good for grappling tree trunks.

Awkward on the ground.
Graceful in the air. This is the reason why the ornithocheirid humerus is so much larger than the femur – not the forelimb launch hypothesis! They put everything into their wings, which transport them to food. Their legs simply enable them to walk out of their eggs.

Figure 2. Arthurdactylus in dorsal view while flying. Note the knife-like wing shape,  that could be maneuvered, like that of a sail plane or swift.

Figure 2. Arthurdactylus in dorsal view while flying. Note the knife-like wing shape, that could be maneuvered, like that of a sail plane or swift. Wings back = less drag, greater speed.

Basically the pterosaur wing in ornithocheirds is a tapering cone, with a large diameter proximally and a tiny diameter distally. This has proved to be a very strong structure from outstretched traffic lights to fishing rods.

Outstretched to swept back
As in swifts, the wings of pterosaurs could have maneuvered in flight from strictly lateral to backswept. Each configuration has their own use, advantage and disadvantage.

References
Liechti, Witvliet, Weber & Bachler 2013. First evidence of a 200-day non-stop flight in a bird. Nature Communications.http://dx.doi.org/10.1038/ncomms3554

The unexpected bipedal/marine connection

Several times in the evolution of reptiles bipedal forms have phylogenetically preceded marine forms. Yes, marine forms. It’s bizarre, but true.

Here’s the list, more or less. Did I miss any?

Huehuecuetzpalli (bipedal capable) > Dinocephalosaurus (marine)
Huehuecuetzpalli, a small speedy lizard with short fore limbs and long hind limbs evolves to become Dinocephalosaurus, a giant long-necked sit-and-wait predator via Macrocnemus, something in between.

Langobardisaurus (biped) > Tanystropheus (marine)
Langobardisaurus, a small long-necked strider evolves to become Tanystropheus, a giant stand-and-wait marine predator.

Eudibamus (biped) > Claudiosaurus (marine)
Eudibamus, a small lizard-like diapsid with a long neck and long hind limbs evolves to become Claudiosaurus, a long-necked marine undulating marine predator of tiny prey. Thereafter descendants evolve to become ichthyosaurs and plesiosaurs.

Varanus (biped while fighting) > Mosasaurus (marine)
Okay, so only certain varanids only go bipedal when fighting, even so mosasaurs are giant and marine.

Scleromochlus & Terrestrisuchus (bipeds) > Metriorhynchus (marine)
Scerlomochlus, and Terrestrisuchus, tiny long-legged basal crocs evolve to become large short-paddled marine crocs, like

Storks (biped) > Penguins (marine)
Flying bipeds evolve to fly underwater.

Australopithecines (biped) > Humans (Homo, marine capable)
(grassland roamers evolve to become able to swim)

Evidently it all comes down to 
Conscious control of breathing — if you want to become a marine animal you have to hold your breath.

Not sure what the bipedal connection is with reptiles, because lots of marine reptiles never had a bipedal phase. I just wanted to throw the idea out there.

More on Humans:
Anthropologist Elaine Morgan on TED talks about the origin of bipedal humans from aquatic apes here. Step-by-step: Apes all walk bipedally when they cross streams. For insulation humans have fat migration to a subdermal position, that’s why obesity is possible for humans, not for apes. The nostrils open ventrally, keeping water out by air pressue in humans. Ape nostrils don’t keep out water, except for the proboscis monkey (the most aquatic of primates).  Ability to speak comes by way of the conscious control of their breath, according to Morgan.

Late Cretaceous pterosaurs, penguins, storks and falcons

A 2006 paper (Slack et al.) on earliest Paleocene penguin (Waimanu manneringi) fossils finds sheds light on early bird diversification and possible decline of the pterosaurs (reduction to only large taxa).

Penguins and storks
According to Slack et al., penguins and storks nest together closer than loons and albatross + petrel. And they must have diversified at 67.1 mya, prior to the K/T extinction.

Falcons and pterosaurs
An earlier diversification, 77.2 mya marked the splitting of the falconiformes from the sea birds (including the above listed taxa). That means falcons or protofalcons were soaring over Late Cretaceous skies. Noting trends for ever larger pterosaurs and the absence  smaller pterosaurs in the Late Cretaceous, the authors report, “Kim et al. (2003) offer the interpretation that pterosaurs might have fed on small birds—equally plausible to us, however, is that the raptors (Falconiformes) could have preyed on young pterosaurs.”

Never heard that one before. Of course, if a predator eats all of its prey, the predator also dies. So, improbable, but interesting.

References
Kim CB, Huh M, Cheong CS, Lockley MG and Chang HW 2003. Age of the pterosaur and web-footed bird tracks associated with dinosaur footprints from South Korea. Island Arc 12:125–131.
Slack KE, Jones CM, Ando T Harrison GL, Fordyce RE Arnason U and  Penny D 2006. Early Penguin Fossils, Plus Mitochondrial Genomes, Calibrate Avian Evolution. Mol. Biol. Evol. 23(6):1144–1155.

How Birds Got Their Wings

A recent article, “How Birds Got Their Wings,” also here, here and here describe work by Dececchi and Larsson (2013) that noted scaling of forelimb vs hind limb took a big turn with Archaeopteryx and kin (Fig. 1). They note, as forelimbs lengthened, they became long enough to serve as an airfoil, allowing for the evolution of powered flight. Shorter legs would have aided in reducing drag during flight — the reason modern birds tuck their legs as they fly — and also in perching and moving about on small branches in trees.

That’s all well and good, but its not the key. It’s one step following the key.
The key is flapping. That’s a behavior that definitely leads to flight. Having long forelimbs vs. hind limbs is also found in primates, chalicotheres and sloths. They don’t fly. Even the “flying lemur” Cynocephalus had long arms. All it can do is glide because it doesn’t flap.

Figure 2. Cosesaurus running and flapping - slow.

Figure 1. Click to animate. Cosesaurus running and flapping – slow.

The key to flapping is a locked down coracoid.
As we learned earlier with Cosesaurus (Fig. 1), a locked down coracoid is one thing pterosaurs and birds share. Cosesaurus had fibers trailing its forelimbs (Ellenberger 1993, Peters 2011) but its forelimbs were too short to fly. Nevertheless, it could flap because it had a locked down coracoid. And that was a secondary sexual trait (behavior) that led to more of the same in three distinct directions in Sharovipteryx, Longisquama and basal pterosaurs.

Taxa in the lineage of birds.

Figure 2. Taxa in the lineage of birds. From top to bottom: Tawa, Juravenator, Sinocalliopteryx, Archaeopteryx, Cathayornis, Sinornithes plus enlarged skulls. Note the coracoid becomes taller and fixed in Archaeopteryx.

Other dinosaurs
with long forelimbs and a tall, narrow, locked down coracoid include oviraptorids, dromaeosaurids, alvarezaurs and birds all taxa that phylogenetically follow Archaeopteryx.

And bats?
They have a locked down tall clavicle that serves the same function. We don’t know when they started flapping because the closest known fossils of prebats are all skull material only.

Reference
Dececchi TA and,  Larsson HCE 2013. Body and Limb Size Dissociation at the Origin of Birds: Uncoupling Allometric Constraints Across a Macroevolutionary Transition. Evolution 67(9):2741 DOI:10.1111/evo.12150

What?? No feathers on velociraptors?

Figure 1. Inside cover illustration spread for "Raptors, the Nastiest Dinosaurs" by Don Lessem, illustrated by David Peters. Don asked for a "no feathers dinosaur" so that's what he got. Don't blame the artist. I tried to persuade. Utahraptor is the big dromaeosaur here.

Figure 1. Inside cover illustration spread for “Raptors, the Nastiest Dinosaurs” by Don Lessem (1996), illustrated by yours truly, David Peters. Don asked for a “no feathers dinosaur” so that’s what he got. Don’t blame the artist. I tried to dissuade. Utahraptor is the big dromaeosaur here.

This post was inspired
by a blog and Flickerstream I ran across here and here that bemoaned the fact that my 1996 dromaeosaurids / velociraptors (Fig. 1) in “Raptors – The Nastiest Dinosaurs” did not have feathers, but did have propatagia.

Guys, I tried to add feathers, as I had done several years earlier (1989) to my own velociraptors in Gallery of Dinosaurs (Fig. 2). However, author Don Lessem insisted that no feathers appear in his book. I tried to dissuade, but was vetoed. After all, he is the author. And that was then. I’m sure Dino Don has come around to new thinking since then.

See how difficult it is to promote a new idea supported by data? Even an expert like Don Lessem balked back in 1995-6.

Figure 2. Feathered Deinonychus from A Gallery of Dinosaurs by David Peters.

Figure 2. Feathered Deinonychus from A Gallery of Dinosaurs by yours truly, David Peters. (1989). Click to enlarge.

So, there is a backstory,
as there is with other controversial aspects of my work. At present the backstory and trashed ideas are not as important as the current work. Science marches on and new data keeps coming in. So let’s stay with the current wave. If you see any other problems with my  tracings or identifications, please let me know of those issues.

References
These are kids books, not academic journals!
“A Gallery of Dinosaurs” is online here.