Is Cycnorhamphus just a baby Moganopterus?

No. 

And yet, when you look at them, Cycnorhamphus has the classic (traditional, false) skull traits that mark it as a juvenile of Moganopterus (Fig. 1, shorter skull, smaller crest and larger eyes, and at 1/5 the size, Cycnorhampus would be just 1.33x larger than a Moganopterus hatchling at 1/8 the size).

So, what’s my point?

 Click to enlarge. The cycnorhamphids. Moganopterus is the largest one and has the longest rostrum, longest crest and smallest eye. Cycnorhamphus, by comparison, has juvenile features. Even smaller cycnhorhamphids also exist in this Gulliverian clade.

Figure 1. Click to enlarge. The cycnorhamphids. Moganopterus is the largest one and has the longest rostrum, longest crest and smallest eye. Cycnorhamphus, by comparison, has juvenile features. Even smaller cycnhorhamphids also exist in this Gulliverian clade. Feilongus is a transitional taxon. Or is it… a teenager??

Many are the pterosaur workers
who think tiny pterosaurs (Fig. 1) are mere juveniles, unworthy of inclusion in phylogenetic analyses. They think (without phylogenetic analysis) that baby pterosaurs had a shorter rostrum and larger eyes, which we falsified earlier several times. (In the same vein the experts should also discount small shrews, rodents and tiny ‘cute’ primates as equally unworthy to be included in mammal analyses.) My point is: size bigotry has been applied across the spectrum of pterosaurs.

If you don’t include tiny pterosaurs in analyses, as seen here, you’ll never figure out what they really are, as seen here.

Large pterosaurs with long crests evolve from smaller pterosaurs with shorter crests or no crests. That’s the way evolution works. But that fact seems to be lost on pterosaur workers who ignore tiny pterosaurs in phylogenetic analyses.

Not Boreopterids
By the way, Feilongus and Moganopterus are listed in Wikipedia and referenced in Witton (2013) as boreopterid ornithocheirids. Jaime Headden has a word to say too. Even though  Feilongus and Moganopterus are known only from skulls, when forced to nest with boreopterids, the shift adds 20 steps to the MPT in the large pterosaur tree. Adding these two to Gegepterus among the ctenochasmatids adds 27 stesp. In the large pterosaur tree, cycnorhamphids are the sisters to ornithocheirids (which include boreopterids), so these mistake are easy to make.

Long eggs are predicted for Moganopterus
Since Pterodaustro demonstrates that long rostrum taxa produce long eggs to house long rostra, it’s easy to predict that the eggs of Moganopterus will likely be long ones, as predicted here for Quetzalcoatlus.

References
Lü J-C, Pu H-Y, Xu i, WuY-H and Wei X-F 2012. Largest Toothed Pterosaur Skull from the Early Cretaceous Yixian Formation of Western Liaoning, China, with Comments On the Family Boreopteridae. Acta Geologica Sinica 86 (2): 287-293.
Bennett SC 1996. On the taxonomic status of Cycnorhamphus and GallodactylusPterosauria: (Pterodactyloidea). – Journal of Paleontology 70: 335–338.
Bennett SC 2010. The Morphology and Taxonomy of Cycnorhamphus. Acta Geoscientica Sinica 31 Supplement 1, The Flugsaurier Third International Symposium on Pterosaurs.
Jiang S-X and Wang X-L 2011. A new ctenochasmatid pterosaur from the Lower Cretaceous, western Liaoning, China. Anais da Academia Brasileira de Ciencias 83(4):1243-1249. online pdf
Quenstedt FA 1855. Über Pterodactylus suevicus im lithographischen Schiefer Württembergs. Doctoral thesis, Universität Tübingen.
Seeley HG 1870. The Ornithosauria: an elementary study of the bones of pterodactyles. – Cambridge: Deighton, Bell, & Co.: xviii + 135 pp., 12 plates.
Wellnhofer P 1970. Die Pterodactyloidea (Pterosauria) der Oberjura-Plattenkalke Süddeutschlands. Abhandlungen der Bayerischen Akademie der Wissenschaften, N.F., Munich 141: 1-133. International Dinosaur Symposium. Geological Publishing House, Beijing 195-203.

wiki/Cycnorhamphus
wiki/Moganopterus

A transitional placodont and the importance of scale bars

Several years ago Jiang et al. (2008) published on the first placodont outside of Europe. The specimen was discussed by them as nesting between the primitive Paraplacodus (Fig. 2) and the more derived, Placodus (Fig. 1). The holotype of the new species, Placodus inexpectatusGMPKU-P-1054 (Fig. 1 in color), was described as 205 cm long.

Figure 1. Click to enlarge. Placodus inexpectatus GMPKU-P-1054, together with two other European Placodus species, P. gigas and P. hypsiceps. The 2008 Chineses placodont shares more traits with P. hypsiceps. The scale bar here reflects the holotype description (probably correct) and the image scale bars that are identified as 10mm. There are three images in Jiang et al (2008). All should read 10 cm, rather than 10mm, if 205 cm is correct for the length.

Figure 1. Click to enlarge. Placodus inexpectatus GMPKU-P-1054, together with two other European Placodus species, P. gigas and P. hypsiceps. The 2008 Chineses placodont shares more traits with P. hypsiceps. The scale bar here reflects the holotype description (probably correct) and the image scale bars that are identified as 10mm. There are three images in Jiang et al (2008). All should read 10 cm, rather than 10mm, if 205 cm is correct for the length. Similar to Paraplacodus and Palatodonta, in P. inexpectatus the lacrimal and prefrontal are not fused to one another

Unfortunately
all three images in Jiang et al. 2008 use a small 10 mm scale bar that probably should have read 10 cm. Above (Fig.1) you’ll see the size relationships if 10 mm is correct. There was no mention of a baby or juvenile in the text. So, 10 mm is probably not correct. If 10cm is correct, then the 2008 placodont was slightly larger than P. hypsiceps or subequal to P. gigas in size, which makes more sense.

Check those scale bars!

Figure 4. Palatodonta is closest to Paraplacodus, a much larger basal placodont.

Figure 2.  Paraplacodus, with a small jugal and an arched quadratojugal. This morphology is close to that of Placodus hypsiceps.

Duplicated results
My phylogenetic analysis also nested P. inexpectatus between Paraplacodus and Placodus gigs, duplicating the Jiang et al. (2008) study results. The former has a lateral temporal fenestra. The later has a solid cheek. Unfortunately, P. inexpectatus provides no further clues as to the infilling of the cheek region. Parts of this area are damaged (see below). P. hypsiceps (Fig. 1) does have a notch posterior to the jugal. This provides one clue to the infilling or lowering of the cheek in P. gigas.

What DGS found.
The preservation of P. inexpectatus is really good, with virtually all bones found articulated. Some toe phalanges are missing due to damage during collection (rock cracks). In the skull, the cheek area was damaged. The top of the coronoid drifted dorsally. A portion of the posterior jugal and maxilla were located near the lower rim of the orbit. Broken edges appear to match. The lower pelvis (pubis and ischium) was not mentioned, but both parts were found. The quadratojugal was not mentioned, but appears to be present in bits and pieces. Hard to say. Phylogenetic bracketing suggests the Jiang et al. (2008) specimen must have had a quadratojugal.

There are at least two distinct Placodus species
P. hypsiceps (Fig. 1) has a taller narrower skull with a notch between the premaxilla and maxilla. P. gigas, the larger of the two, has a lower wider skull and no jawline notch. P. inexpectatus more closely resembled P. hypsiceps. Now there are three.

What about Henodus?
Henodus,
the low, wide placodont with a carapace nests more closely to P. gigas than P. gigas does to P. inexpectatus. That’s because there are no other taxa more Henodus-like than Placodus. And P. inexpectatus shares several traits with Paraplacodus. That happens sometimes.

Prediction
Someday the tall-headed Placodus-like placodonts are not going to be considered congeneric with flat-headed Placodus specimens. Lumpers and splitters can now place their bets.

References
Jiang D-Y, Motani R, Hao W-C, Rieppel O, Sun Y-L, Schmitz L and Sun Z-Y 2008. First Record of Placodontoidea (Reptilia, Sauropterygia, Placodontia) from the Eastern Tethys. Journal of Vertebrate Paleontology 28 (3): 904-908.

Thoracic transverse processes – here and there

In reptiles sometimes the dorsal (thoracic) vertebrae develop elongate transverse processes (Fig. 1). The phylogenetic pattern of these appearances is today’s topic, inspired by Hirasawa 2013.

Note (Fig. 1) that the turtle-like enaliosaur, Sinosaurophargis has elongate thoracic transverse processes. Turtles and near-turtles, like Odontochelys, don’t. So why did Hirasawa et al. (2013) add Sinosaurosphargis to their turtle family tree? Were they influenced by the convergent carapace?

The large reptile tree found the two clades (turtles and saurosphargids) were not related. Turtles nested with the new lepidosauromorphs, while saurosphargids nested with the new archosauromorphs.

from Hirasawa et al. 2013, pink arrow points to elongate transverse processes on Sinosaurosphargis. These are not present on Odontochelys and turtles.

Figure 1. from Hirasawa et al. 2013, pink arrow points to elongate transverse processes on Sinosaurosphargis. These are not present on Odontochelys and turtles. We’ll look at where in the tree such processes do appear  by convergence. 

The appearance of thoracic transverse processes within the Reptilia
You’ll recall that reptiles are essentially diphyletic. We’ll start with one of these clades, then look at the other in the large reptile tree.

The pattern of appearance within the new Lepidosauromorpha
The first appearance of transverse processes in the new Lepidosauromorpha is at the Kuehneosauridae, the gliding reptiles of the Permian to Cretaceous.

The only other clade is the Fenestrasauria (including the Pterosauria) of the Triassic to Cretaceous.

So, no turtles or near-turtles have elongate transverse processes.

The pattern of appearance within the new Archosauromorpha
The entire Synapsida develop elongate transverse processes in the new Archosauromorpha.

The next appearance includes the turtle-like basal enaliosaurs, Sinosaurosphargis (Fig. 1) + Largocephalosaurus.

Eusaurosphargis alone among thalattosaurs develops elongate transverse processes. It also has a wide, flattened torso, but gracile ribs.

Placodonts have elongate transverse processes. So do plesiosaurs, but not nothosaurs or pachypleurosaurs.

The pararchosauriforms from Doswellia to Tropidosuchus all have elongate transverse processes.  (Does Lagerpeton follow this pattern?)

Basal euarchosauriforms up to and including rauisuchids do not have elongate transverse processes. Derived rauisuchia from Yarasuchus and Ticinosuchus through all crocs and dinos (including birds and poposaurs) do have elongate dorsal transverse processes.

Pattern?
Wide flat taxa tend to have elongate transverse processes, whether they are trying to increase their width to glide or to flatten out on the ground or underwater. Even so, many flattened taxa do not have elongate transverse processes.

The stiffening of the torso (less undulating) appears to be the second reason, seen in synapsids, fenestrasaurs, pararchosauriforms and derived rauisuchians.

References
Hirasawa T, Nagashima H and Kuratani S 2013. The endoskeletal origin of the turtle carapace. Nature Communications 4:2107. online here.

How to make evolution look bad

About a year ago
Darren Naish, at his Tetrapod Zoology blog, launched an all out (as opposed to specific pinpoint) attack on ReptileEvolution.com. As you’ll recall, and beyond all logic, he peppered his attack with monstrous renderings from other artists. In the same vein, Naish also included his own version of the large reptile tree (while virtually ignoring the real one, Fig. 2). His self-titled “highly simplified version of the David Peters reptileevolution.com tetrapod tree” version (Fig. 1) included only 14 taxa. And over half of those were new (not included in the original large reptile tree taxon list of 325.)

So once again,
rather than using real data and real evidence from the ReptileEvolution.com website, Darren Naish made up his own tree (Fig.1) and taxa. And by labeling it a “version of the David Peters tree,” Naish set it up (passively in this case) to be ridiculed. Here’s how: Covering such a wide gamut with so few taxa gives the impression that none of these taxa are closely related to one another, or evolve from one another. Which is true! By omitting hundreds of transitional taxa (nodes shown in pink, Fig. 1), Naish’s tree becomes a misrepresentation of the large, robust and fully resolved tree that depends on those hundreds of transitional taxa to show close relationships and evolutionary pathways.

Making up your own evidence and planting it on someone else is typically inadmissible in court. Withholding evidence (omitting hundreds of transitional taxa, ) is likewise frowned upon. Yet Naish still feels justified and proud of his invented journalism.

from Darren Naish, 2012, his take on the large reptile tree, illustrated with seven taxa that are not included in the large reptile tree. The pink numbers represent the number of nodes Naish omitted between nodes he included. None on these taxa look like they are related to one another because all the gradual changes between them have been wiped out.

Figure 1. Click to enlarge. From Darren Naish, 2012, his take on the large reptile tree, illustrated with eight taxa (more than half) that are not included in the large reptile tree. The pink numbers represent the number of nodes from the large reptile tree Naish omitted between his own highly simplified nodes. None on these taxa look like they are related to one another because all the gradual changes between them have been omitted. Key: If a + sign follows a number, the number refers to nodes between basal taxa (eg. basal crocs and basal dinos). If the + sign follows a number it refers to an unknown number of taxa leading to the derived taxon Naish employs to represent the clade.

The failure of prior trees, including Naish’s tree
is in their small size. Too few taxa (14 in Naish’s case) cannot hope to relay the wonders and blends and relationships within the wide gamut of reptile evolution. You need more taxa (at least a magnitude more). And in Naish’s case, you need more basal taxa (no Iguanodon, please).

Naish chose to portray (Fig.1) a derived Cretaceous pterosaur rather than a basal Triassic one. He chose to portray a derived sauropterygian, ichthyosaur, dinosaur, croc, mammal, turtle and frog, none of which are found in the large reptile tree. So there’s massive misrepresentation here. This is not the Peters taxon list. He wanted the taxa to look unrelated, and he succeeded. He wanted to make the reptile evolution tree look bad.

The large reptile family tree.

Figure 2. Click to enlarge. The large reptile family tree. 34o in the main tree, another 32 or so in the therapsid tree. 

If only Naish had listened to the good angel on his other shoulder…
Naish could have shown the actual reptile evolution tree, or segments of it, but he didn’t.  He could have focused on a recovered clade and demonstrated problems within it, but he didn’t.

(Notice, I am using Naish’s own tree in my attack here. It wasn’t that difficult to do.)

As an analogy, Naish’s tree gave us the colors blue, red and yellow without including the gradual spectrum of color transitions between them — which is the whole point of any study of evolution, right?

On a sarcastic note
Using Naish’s “highly simplified” version of evolution (Fig. 1), let’s also show the evolution of humans starting with a sponge, a fly, a starfish, a lamprey, a swordfish, Eryops, a snake, Dimetrodon, Burnetia, a platypus, an elephant, a cat, a rabbit and a tarsier. That’s the same number of taxa that Naish used and in the correct phylogenetic order. But the evolutionary transitions are just too difficult to understand because basal taxa are not used.

This is how Darren Naish made evolution look bad.

By contrast —

This is how to make evolution look good.
If you are interested in any genus listed on the large reptile tree, you can find it at ReptileEvolution.com. Look it up and you can link to any number of predecessors and descendants (if there are any), relatives and offshoots. You’ll see that related taxa share a very large suite of traits. Unrelated taxa don’t share as many traits. You’ll be able to read what traits are new and what traits have become vestiges. Sadly, such rich details are missing from Naish’s “highly simplified” tree. In large gamut evolutionary studies 14 taxa cannot provide the same value as 340. To “highly simplify” evolution is to misrepresent it and make it unintelligible and laughable. Naish’s version of simplification has the same effect as removing 20 or more letters from the alphabet.

The power and value of ReptileEvolution.com
is in the number of included taxa, each one a slight variation from its closest relative. The whole point is to get closer to these transitions so you can begin to understand the natural selection trends and the gradual evolutionary processes that occurred back then. Here you’ll get higher resolution by removing the evolutionary distances between related reptiles. And you do this by increasing the number of included taxa.

More is better!!!!

You just can’t get such high resolution and increased understanding from a mere 14 taxa in a “highly simplified” tree.

A year later Naish still doesn’t understand his error. He thinks he did the world a great favor by exposing the “sham” behind ReptileEvolution.com. Hopefully someone someday will point out to him that, in this case, his over “simplification” was the real sham.

Two unlikely forelimb launching pterosaurs

Today we’ll look at two very different pterosaurs and wonder how it was even possible that these should be considered to be forelimb launchers.

The first is the basal pterosaur, MPUM 6009 (Fig. 1). It has the longest hind limbs compared to fore limbs. In these pterosaurs the hind limb leap alone would obviate the need for further spring off the forelimbs. Moreover, putting the short forelimbs on the substrate demands an awkward butt-high configuration unlikely to provide any sort of efficient launching. Phylogenetically all pterosaurs following this one had longer forelimbs capable of touching the substrate without losing balance over the toes.

MPUM 6009 with red and orange layers applied to show muscles. The hind limbs are well muscled, fully capable of leaping. The forelimbs are incapable of touching the ground without a very awkward butt-high configuration.

Figure 1. MPUM 6009 with red and orange layers applied to show muscles. The hind limbs are well muscled, fully capable of leaping. The forelimbs are incapable of touching the ground without a very awkward butt-high configuration.

Basal pterosaurs, derived from long-legged flapping fenestrasaurs like Longisquama, had longer hind limbs than forelimbs. This legacy of this hind limb leaping cannot be ignored.

 A completely different situation here with Nyctosaurus bonneri, in which the forelimbs are much longer than the hind limbs. Could those forelimb muscles provide a sufficient leap to clear the ground with those giant wing fingers before it comes crashing back to earth. Better to extend the wings while bipedal on those meaty thighs, then start flapping, running and leaping.

Figure 2. A completely different situation here with Nyctosaurus bonneri, in which the forelimbs are much longer than the hind limbs. Could those relatively small forelimb muscles provide a sufficient leap to clear those giant wing fingers before crashing back to earth? Better to extend the wings while bipedal on those meaty thighs, then start flapping, running and leaping, adding thrust with each wing flap.

When the forelimbs are much longer than the hind limbs
Nyctosaurus (Fig. 2) is the prime example of pterosaurs with the opposite morphology: longer forelimbs than hind limbs. Here it is hard to imagine this pterosaur becoming airborne without extending its wings for lift. The meaty thighs could have kept this pterosaur balanced over its toes while the wings unfolded. The meaty thighs could also have provided an initial leap or run to launch. Such large wings would have provided extra thrust, but only while extended. The triceps muscles appear to be pitifully too small to rapidly extend the forelimb to launch the pterosaur like a super pogo-stick.

Most other pterosaurs have a more balanced configuration with forelimbs and hind limbs more closely related in terms of length and the placement of joints. Even these were able to raise their forelimbs off the substrate to unfold the wings without losing balance over the toes.

Causes of the problem
Shortchanging the muscles of the pelvis, prepubis and femur by Witton (2013) and others is only one cause of their false paradigm. Creating poor reconstructions that disfigure real morphology is the second problem. Putting faith in imaginary ancestors with odd and improbable morphologies rather than verifiable fossil ancestors with real bones is the third cause.

That’s why I’m here, to encourage change based on evidence.

Scathing Book Review – Pterosaur hind limb muscles and the prepubis: Witton vs Peters

Earlier here, here and here we had a critical look at the hypotheses regarding various aspects of pterosaur phylogeny and morphology. Today we’ll look at the muscles of the pterosaur hind limb and how Witton (2013) emaciated them.

Pterosaur hind limb muscles according to Witton (2013, above) and based on lizard musculature (Fig. 2).

Figure 1. Pterosaur hind limb muscles according to Witton (2013, above) and based on lizard musculature (Fig. 1, below and Figs. 2, 3). Witton does not extend femoral muscles to the prepubis or the anterior ilium. Evidently it’s important for those who do not want pterosaurs to exhibit any bipedal abilities to denigrate hind limb muscle strength, as shown by the emaciated appearance Witton gives them and by reducing their anchorage.

Make sure those hind limbs look emaciated
if you want to convince others that pterosaur hind limbs were not capable of providing bipedal locomotion (in step with quadrupedal locomotion for most) or hindlimb leaping/launching/takeoff. Witton 2013 emaciates his pterosaur femoral muscles and reduces their points of origin on the ilium and prepubis. Why? He supports the forelimb launch hypothesis for pterosaurs big time.

Two dead lizards, dorsal and ventral views. Note the meaty thighs.

Figure 2. Two dead lizards, dorsal and ventral views. Note the meaty thighs. Same as in birds and crocs. Witton emaciates them.

Real lizard femoral muscles are robust and meaty (Figs. 2,3 ). The muscles get thicker at mid thigh. This even happens in birds and crocs! Why would Witton emaciate them?

Lizard muscles according to Romer (1956. 1062,1971). Ilium muscles in red. Pubis and ischium muscles in blue. Caudal muscles in yellow.

Figure 3. Lizard muscles according to Romer (1956. 1062,1971). Ilium muscles in red. Pubis and ischium muscles in blue. Caudal muscles in yellow. Curious that no muscles arise from the posterior ilium.

No Prepubis Anchor
Pterosaurs extend their ventral muscle anchorage by adding a prepubis, which can be very long indeed in Rhamphorhynchus (Fig. 2) and Campylognathoides (Fig. 3). No muscles attach to the prepubis in Witton’s version (Fig. 1). One wonders why not, especially when the prepubes and femora are aligned during normal locomotion (Figs. 2-4).

Instead Witton 2013 follows Claessens et al. (2009) mistake when he reports the prepubes “were capable of moving up and down with each breath taken by their owner.” This “rotating prepubis” hypothesis was falsified earlier based on the Claessen et al. use of a flipped and partial prepubis to support their hypothesis. They got the bone upside down!! No other prepubes in any other pterosaurs support the Claessen et al. hypothesis. The pubis/prepubis joint is a butt joint in all pterosaurs. So it basically cannot move. The prepubis acted as an extension to the pubis. Pubofemoralis muscles probably extended down the prepubis as if it were an elongated pubis. Respiration occurred by expansion of the ribs, as in all tetrapods, not by the rotation of the prepubes. Correctly configuration shown below (Figs. 2-4).

The darkwing Rhamphorhynchus JME SOS 4785

Figure 2 The darkwing Rhamphorhynchus JME SOS 4785. Note the depth of the prepubis. Even if this prepubis could rock back and forth it would not further deepen the torso.

 The Pittsburgh specimen of Campylognathoides. This pterosaur had the largest prepubes of all pterosaurs. Note the ventral orientation, aligned with the femora during normal standing.

Figure 3. The Pittsburgh specimen of Campylognathoides. This pterosaur had the largest prepubes of all pterosaurs. Note the ventral orientation, aligned with the femora during normal standing. Note the butt joint between the pubis and prepubis.

The Triebold Pteranodon, one of the most complete ever found. The metacarpals are quite a bit longer here. So is the beak.

Figure 4. The Triebold Pteranodon, one of the most complete ever found. I have this skeleton cast. The prepubes extend ventrally, in line with the femora and unable to expand the torso during respiration. Expanding ribs, as in all tetrapods, provided all the necessary torso expansion for respiration.

Witton's prepubis mistakes, based on mistakes by Claessen et al. 2009. (Above) in Rhamphorhynchus the prepubis is waaaay too small. In both the prepubis is incorrectly oriented and incorrectly attached to the pubis.

Figure 5. Witton’s prepubis mistakes, based on mistakes by Claessen et al. 2009. (Above) in Rhamphorhynchus the prepubis is waaaay too small. In both pterosaurs the prepubis is incorrectly oriented and incorrectly attached to the pubis.

Elongate ilia
And why would the all pterosaur ilia extend so far anterior (especially so in Sos 2428), framing so many sacrals (Fig. 1), without bringing a few muscles with them? After all, that’s what mammals and dinosaurs do. And the muscles arising from the ilium in lizards concentrate anteriorly. Finding homologies and analogies is how we find the most parsimonious answer.

The missing caudofemoralis
Lizards and most dinosaurs have a robust tail with elongate transverse processes and deep chevrons. These are muscle anchors for the caudofemoralis, tail muscles that pull the femur posteriorly, contributing to the step cycle. In birds and pterosaurs these muscle anchors are largely, but not completely missing. The pelvis (and prepubis) have taken over those duties. The caudofemoralis is largely, but not completely missing in birds and probably pterosaurs. As in birds, pterosaur the anchoring transverse processes are vestigial or missing and their chevrons, where present, extend parallel to the caudal centra, not ventrally. In pterosaurs, chevrons are not caudofemoralis anchors, but secondarily adapted as tail stiffeners. They are essentially absent in basal pterosaurs, like MPUM6009. They redevelop in several taxa. These same caudal patterns (attenuated tails) are found in pterosaur precursors, the fenestrasaurs, evolving from less attenuated tails in tritosaur lepidosaurs, a key trait that ties them all together.

It’s important to examine living animals to see their muscle patterns in order to reconstruct them in prehistoric animals. It’s important to know what new bones, like the prepubis, are used for (not respiration). It’s important to note the details in a skeleton, establishing articular surfaces and creating accurate reconstructions.

References
Claessens, LPAM, O’Connor PM and Unwin DM 2009. Respiratory Evolution Facilitated the Origin of Pterosaur Flight and Aerial Gigantism. PLoS ONE 4(2):e4497.http://www.plosone.org/article/info:doi/10.1371/journal.pone.0004497
Romer AS 1971. The Vertebrate Body (shorter version). WB Saunders Co. 452 pp.
Witton M. 2013. Pterosaurs. Princeton University Press. 291 pages.x

A new(?) tiny “pterodactyloid” (from 1841!) with a short neck

 Tiny Pterodactylus? pulchellus (=micronyx) from the National History Museum London. Some DGS has been applied to bring out certain details.

Figure 1. Tiny Pterodactylus? pulchellus (=micronyx) from the Natural History Museum London. Some DGS has been applied to bring out certain details. If your screen resolution is 72 dpi, then you’re seeing this fossil full size.

In the new book, Pterosaurs (Witton 2013:198), a tiny pterosaur with a 3 cm long skull with a long rostrum was pictured (Fig. 1). Witton identified the tiny pterosaur as a juvenile in the Natural History Museum London collection. After process of elimination, I’m guessing this is a Solnhofen (Late Jurassic) specimen PV R 2721 attributed by Meyer (1841) to Pterodactylus puchellus. [I could be wrong.] Later workers called it P. micronyx. I don’t know the Wellnhofer (1970) number.

Here it is at full scale (Fig. 1, if your screen is set to 72dpi). The inset shows the pes reconstructed. The pes alone with its long metatarsal 1 identifies it as a descendant of the scaphognathids (Peters 2011). Phylogenetic analysis nested it between another tiny pterosaur (but slightly larger) with a shorter rostrum, GMU-10157 (Fig. 2) and Cycnorhamphus (Fig. 3) a much larger specimen.

Notice the resemblance? 

. GMU-10157 (above) and the Meyer 1841 specimen (below) to the same scale.

Figure 2. GMU-10157 (above) and (I think) the Meyer 1841 specimen PV R 2721 (below) to the same scale. The Meyer specimen is slightly smaller overall, yet has a longer rostrum and nests at the base of the Cycnorhamphus clade. GMU-10157 nests at the base of the cycnorhamphids + ornithocheirids.

The interesting thing…
The Meyer 1841 specimen is actually smaller than GMU-1-157, and yet it has a longer rostrum! That breaks one of the “rules” under the old allometric ontogenetic growth paradigm. Here these two tiny adults are part of a long gradual evolutionary continuum of size reduction and enlargement (Fig. 3). And this, ladies and gentlemen, is how you evolve a Cycnorhamphus. It’s the closest known outgroup taxon. Further out GMU-10157 nests at the base of the cycnorhamphids + ornithocheirids.

Cycnorhamphus, its sisters and predecessor taxa

Figure 3. Cycnorhamphus, its sisters and predecessor taxa, sans the Meyer 1841 specimen.

Witton (2013) considered Cycnorhamphus a ctenochasmatoid, related to Pterodactylus and Ctenochasma. They’re not related according to the results of the large pterosaur family tree (where the Meyer specimen will shortly be added). You have to go back to Dorygnathus to find a last common ancestor. If you eliminate Ctenochasma then Scaphognathus is the last common ancestor. Obviously, given the generic name Meyer (1841) applied to this specimen, this sort of mistake has been going on for a long, long time.

Reconstruction of the tiny London specimen.

Figure 4. Reconstruction of the tiny London specimen, shown larger than actual size. Derived from a sister to the GMU specimen (Fig. 2), the London specimen was ancestral to cycnhorhamphids. A great pes subdivided by PIL (parallel interphalangeal lines). You can even see the very beginnings of that dentary bend that reaches its acme in the bent-jaw cyc (Fig. 3). But no long legs yet.

The short neck problem
Darwinopterus was promoted as a transitional pterosaur, having the long rostrum and long neck of a pterodactyloid, but the remainder of the body with its long tail and long toe 5 were pre-pterodactyloid. The Meyer specimen, along with others, then presents a problem. It has a short neck and, for that matter, a shorter rostrum than Darwinopterus. GMU 1-157 has an even shorter rostrum. TM-13104 (Fig. 3) has an even shorter rostrum and longer metacarpals, yet it nests as a descendant of Scaphognathus.

Expectations and reality all fall apart rather quickly if you hang your hat on Darwinopterus, a specimen that is a “dead end” taxon in the large pterosaur family tree. Expand the gamut in your taxon list and see what new relationships emerge.

No such problems here.
If you don’t believe me that this is a tiny adult in the lineage of cycnorhamphids, just add it to your own analysis. Repeating the test is good Science. Throwing insults from the sidelines is not, unless they come with good evidence in tow. It is also possible that this specimen is young. Without an eggshell beside it, the tiny pterosaurs give few clues as to their ontogenetic age, other than their phylogenetic nestings and the sizes of their sisters. Here the sizes vary considerably.

Pterosaur workers have been avoiding tiny pterosaurs, denigrating them as pre-morph juveniles, when tiny pterosaurs hold the key to understanding pterosaur relations. Similarly pterosaur workers have been avoiding tritosaur/fenestrasaur/lepidosaurs, when they hold the key to pterosaur origins.

Take a good look at that skull
With that long concave rostrum, procumbent anterior teeth and pelvis shape in the Meyer specimen, we’re getting very close to the morphology of Cycnorhamphus. There’s no fronal/parietal crest yet. The long neck, long legs and longer metacarpals were yet to come. The free fingers were likewise getting close in proportion to one another.

If this is not the Meyer 1841 specimen,  PV R 2721, please let me know to make the correction.

References
Witton M. 2013. Pterosaurs. Princeton University Press. 291 pages.

How some bats take flight: these use their hind legs or wings as wings

Bat take-off has recently become pertinent with regard to pterosaur take-off. Expanding on earlier studies, recent high-speed X-rays of bats taking flight from a horizontal surface reveal that either:

1. the hind limbs provide the initial thrust skyward, followed by huge wing flaps, or

2. the wing flaps alone provide the initial thrust skyward.

3. The third type of launch, is that of the vampire bat using forelimbs as pogo sticks, which has been receiving all the attention lately with regard to pterosaur take-off.

Dr. Konow, the author of the study also measured the change in the length of the bats’ muscles and tendons, which revealed their stretchy, energy-storing properties.

“Most small mammals have stiff, thick tendons so they cannot stretch or store energy in them like we do in our Achilles tendon when we run or walk,” he explained. “But this 20g fruit bat stores energy as it stretches its bicep and tricep tendons during take‐off and climbing flight.” Releasing this “elastic energy” – just like a stretched rubber band snapping back – gives the animal an extra power boost.

The study was presented here at the Society for Experimental Biology and has not yet been formally published. Videos are available here.

Pterosaur Heresies is about 2 years old now

And, despite all the evidence I try to cram into this blog, it’s still reviled and dismissed by several professional paleontologists. Something odd about that… Providing testable answers to long standing mysteries is evidently not to be encouraged! You would think at least a few of them would say, “Hey, that’s a different idea. Let’s run the big Kahuna through a test or two!” Instead the strange bedfellows are defended. That’s the paradigm.

I’m still hoping that someone will add some suggested taxa to their phylogenetic analyses to see if they can confirm the results of the large reptile and large pterosaur trees.  So far there have been no testers.

I wish someone would go take a studied look at Cosesaurus and remap the thing again (as detailed as here or Ellenberger 1993) to see what they come up with. Same with Longisquama and Sharovipteryx. Considering their importance, it’s at least worth a try.

Or does confirming anything in the heresies come at some professional cost?

I have been vindicated by the discovery of bipedal pterosaur tracks and Kellner’s confirmation of the pteroid articulation on the radiale (Peters 2009). Nice to see.

The taxon lists keep growing in both studies. Reptiles have surpassed 340. Pterosaurs are past 220.

Google has been very good to the site and its figures.

The number of visitors and page views holds steady between 8000 and 11000 view a month. Unique visitors are a third of those numbers. More readers are subscribed now than ever before. The subject matter is a niche within a niche, so I’m happy to have the steady readers I do.

I’ve tried to keep up a steady stream of posts, one per day, seven days a week. So far, so good, keeping to that average as we’re up to some 740 posts now. There have been times when I thought I was out of subject matter, but then a fresh truckload comes in and I can do a week’s worth. Even so, the pace will undoubtedly slow down as most of the best subjects have been posted already and Witton’s new book only brought up old subjects to be repeated. Even so, it also gave me an opportunity to take a fresh look at lizard tendons.

The process of discovery is the driving force. It’s a wonderful reward to be able to see something with fresh vision and understand how it works. It’s almost as fun to disassemble bad hypotheses and show why they don’t work. Keep those cards and letters coming!

I will always wonder how certain workers have been able to promote bad ideas and how the next generation gloms onto them. I’ve only seen one scientist back down off a claim: Kevin Padian, at the sight of the Crayssac tracks admitted that certain pterosaurs were indeed quadrupeds. So, it can happen, but it takes a landslide.

Thank you for your thoughts and thank you for your loyal readership whether you’re interested in what I have to write or whether you’re just waiting for me to slip up so you can reprimand me.

It’s been an interesting and rewarding two years.

I’ll see some of you at SVP in L.A toward the end of October. My abstract will be a poster.

Scutellosaurus and Scelidosaurus. They don’t nest together?

In response to a reader’s query on Scutellosaurus and Scelidosaurus (Fig. 1), we’ll take a closer look at these two taxa and why they don’t nest together in the large reptile tree. Unfortunately the skull is poorly known in Scutellosaurus.

Figure 1. Scelidosaurus and Scutellosaurus to scale and to the same relative length. Why don't they nest together? They both have armor. The both resemble one another in several details. Phylogenetic analysis shows that three included taxa separate these two as Scutellosaurus nests with Lesothosaurus.

Figure 1. Scelidosaurus and Scutellosaurus to scale and to the same relative length. Why don’t they nest together? They both have armor. The both resemble one another in several details. Phylogenetic analysis shows that three included taxa separate these two in the large reptile tree. Scutellosaurus nests more pasimoniously with Lesothosaurus (Fig. 2). The osteoderms may have been convergent.

To move Scutellosaurus to Scelidosaurus adds 14 steps. To move Scelidosaurus to Scutellosaurus adds 10 steps. Only two intervening nodes and three taxa, Heterodontosaurus, Hexinlusaurus and Agilisaurus, separate them.

The following traits link Scutellosaurus to Scelidosaurus:

  1. Ventral mandible concave then convex
  2. Pedal digit 4 is longer than metatarsal 4
  3. Osteoderms

The following traits separate Scutellosaurus from Scelidosaurus. These traits are shared with closer kin, either Agilisaurus or Lesothosaurus.

Scelidosaurus 

  1. Number of cervicals: eight
  2. Cervicals decrease cranially
  3. Chevrons not broader proximally
  4. Olecranon process present
  5. Acetabulum semi perforate
  6. Tibia/femur ratio less than
  7. Fibula diameter greater than half of tibia
  8. Metatarsal 1 50-75% of mt3
  9. Metatarsal 5 present and all other digit V traits
  10. Pedal 1.1 has no alignment with metatarsals 2 and 3

Scutellosaurus

  1. Number of cervicals: seven
  2. Cervicals do not decrease cranially
  3. Chevrons broader proximally
  4. Olecranon process not present
  5. Acetabulum perforate
  6. Tibia/femur ratio not less than 1
  7. Fibula diameter not greater than half of tibia
  8. Metatarsal 1 less than 50% of mt3 (rebuilt using PILs)
  9. Metatarsal 5 absent  and all other digit V traits
  10. Pedal 1.1 aligns with metatarsals 2 and 3.

There were other differences between Scutellosaurus and Scelidosaurus, but they were not shared with sister taxa. For example, Scutellosaurus has a short femur, shorter than half the glenoid/acetabulum distance. There is also no indication of a predentary (Fig. 2). In Scelidosaurus the longest pedal digits (measured from the heel) are 2 and 3, not just 3 as in other dinosaurs.

If there are any errors here, I’ll correct them.

Figure 2. Scutellosaurus and two versions of Lesothosaurus. While more similar in size, these two also nest closer together than either does to Scelidosaurus. Perhaps the armor was convergent.

Figure 2. Scutellosaurus and two versions of Lesothosaurus. While more similar in size, these two also nest closer together than either does to Scelidosaurus. Perhaps the armor was convergent.

Arising from a sister to Daemonosaurus, ornithischians, like Scelidosaurus, were not tiny dinosaurs at their base. Some, like Lesothosaurus and Scutellosaurus became smaller in the Jurassic.

References
Barrett PM, Butler RJ and Knoll F 2005. Small-bodied ornithischian dinosaurs from the Middle Jurassic of Sichuan, China. Journal of Vertebrate Paleontology 25:823-834.
Colbert EH 1981. A primitive ornithischian dinosaur from the Kayenta Formation of Arizona. Bulletin of the Museum of Northern Arizona 53:1-61.
Galton PM 1978. Fabrosauridae, the basal family of ornithischian dinosaurs (Reptilia:Ornithopoda). Paläontolgische. Zeitschrift 52:138–59.
He X-L and Cai K-J 1983. A new species of Yandusaurus (hypsilophodont dinosaur) from the Middle Jurassic of Dashanpu, Zigong, Sichuan. Journal of Chengdu College of Geology, Supplement 1:5-14.
Knoll F, Padian K and de Ricqles A 2009. Ontogenetic change and adult body size of the early ornithischian dinosaur Lesothosaurus diagnosticus: implications for basal ornithischian taxonomy”. Gondwana Research online preprint: 171. doi:10.1016/j.gr.2009.03.010.
Norman D 2001. Scelidosaurus, the earliest complete dinosaur in The Armored Dinosaurs, pp 3-24. Bloomington: Indiana University Press.
Sereno PC 1991. Lesothosaurus, “fabrosaurids,” and the early evolution of Ornithischia. Journal of Vertebrate Paleontology 11(2):168-197
Thulborn, RA 1977. Relationships of the lower Jurassic dinosaur Scelidosaurus harrisonii. Journal of Paleontology. 51: 725-739

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wiki/Agilisaurus
wiki/Hexinlusaurus
wiki/Scelidosaurus
wiki/Scutellosaurus
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