Paul Ellenberger RIP

I just learned of the death in 2016
of Paul Ellenberger, a French paleontologist from Montpellier, who reached the age of 97 and wrote about Cosesaurus and several ichnotaxa, as we learned earlier here, here and here.

Ellenberger was kind enough
to host me, a stranger, for a day and a night, following my visit to Cosesaurus in Barcelona in the mid 1990s. We talked about it. I tried to convince him that he should be pleased to be the discoverer of the ‘mother of all pterosaurs‘, but he continued to insist it was a pre-bird. His discovery was published in 1974, but his conclusions were invalidated by several others, including Sanz and López-Martinez 1984, who considered Cosesaurus a juvenile Macrocnemus (which is close, but no cigar) and a lepidosaur (which was later confirmed by the large reptile tree.)

Figure 1. Cosesaurus insitu. No bones are present. This is a natural mold that includes an amorphous blob, a jellyfish, that trapped one foot of this unique specimen.

Figure 1. Cosesaurus insitu. No bones are present. This is a natural mold that includes an amorphous blob, a jellyfish, that trapped one foot of this unique specimen. This is a sister to the ancestor of pterosaurs. Note the antorbital fenestra without a fossa, convergent with proterosuchids.

Sad news about Cosesaurus
The authors of the Wikipedia Cosesaurus page have erased nearly all (but see below) data and references to Peters 2000a, the first paper that included Cosesaurus and related taxa added to several previously phylogenetic analyses that included archosaurs and pterosaurs. That study found pterosaurs nested with Cosesaurus and kin, not archosaurs in every analysis. The removal of this citation from the Wiki page is equivalent to sweeping data under the rug. Peters 2000a was a peer-reviewed publication in a respected academic journal.

If you’re looking for the ancestors of pterosaurs,
Cosesaurus is where you look. You can test the Peters 2000 hypothesis yourself with your own observations and phylogenetic analysis.

Perhaps an oversight,
the Wikipedia authors failed to delete the image of Cosesaurus that I provided several years ago with this caption:

“Here is the fossil known as Cosesaurus aviceps, the sole specimen of this genus. Although lizard-like in appearance, this Middle Triassic fenestrasaur/lizard had certain traits that place it on the lineage of Sharovipteryx, Longisquama and pterosaurs. Among these traits are: an elongated narial opening, an antorbital fenestra, a very large orbit, a spike-like quadratojugal, a strap-like scapula, a stem-like coracoid, an enlarged sternum displaced anteriorly to align with transverse clavicles, a pteroid, an elongated anterior process of the ilium, a sacrum consisting of four vertebrae, a prepubis, a simple hinge ankle joint without fusion of the astragalus and calcaneum, a calcaneum without a “heel” and an elongated pedal digit 5, plus soft tissue membranes arising from the trailing edges of the limbs and the dorsal margin of the spine and skull. No digits were vestigial, but manual digit V was reduced.”

As you might remember
earlier the authors of the Wikipedia page on pterosaurs lied with regard to my access to fossils. This line of thinking follows in lockstep Darren Naish’s bogus propaganda regarding the ReptileEvolution.com website, reviewed here. Naish’s blog and other efforts has gained followers and that’s not good for science. I hate to say it, but he’s going to come out as the leader of his suppressive minions when historians look back at this decade, unless he comes out and redeems himself soon. In private correspondence, I recently invited Naish to comment on the several recent papers that confirmed nestings first discovered in the LRT, but he dismissed that invitation. So we’ll have to fight this suppression of data a while longer.

References
Ellenberger P and de Villalta JF 1974. Sur la presence d’un ancêtre probable des oiseaux dans le Muschelkalk supérieure de Catalogne (Espagne). Note preliminaire. Acta Geologica Hispanica 9, 162-168.
Ellenberger P 1978. L’Origine des Oiseaux. Historique et méthodes nouvelles. Les problémes des Archaeornithes. La venue au jour de Cosesaurus aviceps (Muschelkalk supérieur) in Aspects Modernes des Recherches sur l’Evolution. In Bons, J. (ed.) Compt Ren. Coll. Montpellier 12-16 Sept. 1977. Vol. 1. Montpellier, Mém. Trav. Ecole Prat. Hautes Etudes, De l’Institut de Montpellier 4: 89-117.
Ellenberger P 1993. Cosesaurus aviceps . Vertébré aviforme du Trias Moyen de Catalogne. Étude descriptive et comparative. Mémoire Avec le concours de l’École Pratique des Hautes Etudes. Laboratorie de Paléontologie des Vertébrés. Univ. Sci. Tech. Languedoc, Montpellier (France). Pp. 1-664.
Peabody FE 1948. Reptile and amphibian trackways from the Lower Triassic Moenkopi formation of Arizona and Utah. University of California Publications, Bulletin of the Department of Geological Sciences 27: 295-468.
Peters D 2000a. Description and Interpretation of Interphalangeal Lines in Tetrapods. Ichnos 7:11-41.
Peters D 2000b. A Redescription of Four Prolacertiform Genera and Implications for Pterosaur Phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia 106 (3): 293–336.
Peters D 2009. A reinterpretation of pteroid articulation in pterosaurs. Journal of Vertebrate Paleontology 29: 1327-1330
Sanz JL and López-Martinez N 1984. The prolacertid lepidosaurian Cosesaurus aviceps Ellenberger & Villalta, a claimed ‘protoavian’ from the Middle Triassic of Spain. Géobios 17: 747-753.

wiki/Cosesaurus

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Macrocnemus skull in DGS

This started with
a fuzzy photo of a  complete fossil Macrocnemus specimen, PMR T2472 (Fig 1).

Figure 1. GIF animation of PMR T2472, a large Macrocnemus in situ and reconstructed from a fuzzy photo.

Figure 1. GIF animation of PMR T2472, a large Macrocnemus in situ and reconstructed from a fuzzy photo.

Many specimens attributed to Macrocnemus
are known, each one a little different phylogenetically. Reports of a ‘juvenile’ Macrocnemus refer to the phylogenetically basalmost and smallest of the known specimens, the one closest to its outgroup taxon, the tritosaur lepidosaur, Huehuecuetzpalli.

It’s good to remind yourself
before reading the reference titles, that Macrocnemus and kin are not protorosaurs (= prolacertiforms), nor are they archosauriforms. Even I made the same mistake (Peters 2000b) in my more naive days before the LRT recovered Macrocnemus and kin as tritosaur lepidosaurs in Peters 2007.

From this rather ordinary taxon arises 
such diverse and exotic taxa as Dinocephalosaurus, Sharovipteryx, a variety of Tanystropheus, several Langobardisaurus, Longisquama and pterosaurs. Peters 2007 reported, “The basal lizard, Huehuecuetzpalli is the most primitive taxon in this newly revealed third squamate clade between Iguania and Scleroglossa. Two branches arise from it. Jesairosaurus is basal to the Drepanosauridae. Three distinct specimens of Macrocnemus give rise to the Tanystropheidae,the Langobardisaurinae and to the Fenestrasauria respectively.” Jesairosaurus and Drepanosauridae are now basal lepidosauriformes.

References
Li C, Zhao L-J and Wang L-T 2007A new species of Macrocnemus (Reptilia: Protorosauria) from the Middle Triassic of southwestern China and its palaeogeographical implication. Science in China D, Earth Sciences 50(11)1601-1605.
Li C, Wu X-C, Zhao L-J, Nesbitt SJ, Stocker MR, Wang L-T 2016. A new armored archosauriform (Diapsida: Archosauromorpha) from the marine Middle Triassic of China, with implications for the diverse life styles of archosauriforms prior to the diversification of Archosauria. The Science of Nature 103: 95. doi:10.1007/s00114-016-1418-4
Nopcsa F 1931. Macrocnemus nicht Macrochemus. Centralblatt fur Mineralogie. Geologic und Palaeontologie; Stuttgart. 1931 Abt B 655–656.
Peters D 2000b. A Redescription of Four Prolacertiform Genera and Implications for Pterosaur Phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia 106 (3): 293–336.
Peters D 2007. The origin and radiation of the Pterosauria. In D. Hone ed. Flugsaurier. The Wellnhofer pterosaur meeting, 2007, Munich, Germany. p. 27.
Peyer B 1937. Die Triasfauna der Tessiner Kalkalpen XII. Macrocnemus bassanii Nopcsa. Abhandlung der Schweizerische Palaontologische Geologischen Gesellschaft pp. 1-140.
Renesto S and Avanzini M 2002. Skin remains in a juvenile Macrocnemus bassanii Nopsca (Reptilia, Prolacertiformes) from the Middle Triassic of Northern Italy. Jahrbuch Geologie und Paläontologie, Abhandlung 224(1):31-48.
Romer AS 1970. Unorthodoxies in Reptilian Phylogeny. Evolution 25:103-112.

wiki/Macrocnemus

 

More data on the scaly fenestrasaur, Kyrgyzsaurus

Updated March 3, 2016 with a reconstruction from the tracings.

An earlier nesting
in the large reptile tree placed the Late Triassic reptile Kyrgyzsaurus not with drepanosaurs, but with fenestrasaurs, between Cosesaurus and higher taxa, all bipeds or near bipeds. The parallelogram-shaped cervicals indicate the skull was held higher than the shoulders, as in pterosaurs, Longisquama and Cosesaurus. 

Figure 1. New data on Kyrgyzsaurus provides the first evidence for forelimbs.

Figure 1. New data on Kyrgyzsaurus provides the first evidence for forelimbs. This is the first time I’ve seen the bones in color. Note: Spindler thought the forelimb was tiny, but did not trace left forelimb elements, only the elbow visible over the dorsals. This is an example of DGS. Higher resolution would enable further details to be traced.

New photos
(Fig. 1) of what appear to have come from an abstract posters provided online by Spindler et al. 2014 reveal more data for Kyrgyzsaurus, including a complete pectoral girdle and tiny forelimb with laterally folding digit 4 (as in pterosaurs), adding to the possibility that long hind limbs probably gave this taxon a bipedal configuration as well (based on phylogenetic bracketing). Longisquama and Sharovipteryx were sisters and contemporaries that likewise had short arms.

Figure 2. Updated figure of Kyrgyzsaurus.  Note the tiny forelimbs and large hyoid, as in Sharovipteryx.

Figure 2. Updated figure of Kyrgyzsaurus. Note the tiny forelimbs and large hyoid, as in Sharovipteryx.

The abstract discusses
coloration in the scales, not unexpected as exquisitely preserved Late Triassic insects likewise preserve coloration in this formation.

From the poster
“Dorsally the scales are generally smaller, but conspicuous craniocaudal rows of large oval to rectangular scales occur within the meshwork of smaller scales. The reddishly preserved skin colouration follows no simple pattern: There is a larger color patch along the posterior margin of the skull, the ventral neck and anterior trunk display scales with tiny colour spots, and the dorsal rows of larger scales are sometimes marked by thin aligned stripes.”

Figure 3. The origin of pterosaurs now includes Kyrgyzsaurus, nesting between Cosesaurus and Sharovipteryx.

Figure 3. The origin of pterosaurs now includes Kyrgyzsaurus, nesting between Cosesaurus and Sharovipteryx. Click to enlarge.

Unfortunately Spindler et al.
were unable to decipher their own precise tracings and so overlooked the forelimb of Kyrgyzsaurus. In this case it might have been important for them to understand where this specimen nested in the reptile family tree (published here in 2012). They considered it merely as ‘a reptile’ with tiny forelimbs with very, very small fingers, evidently imagined. They did not even call it Kyrgyzsaurus, or make reference to the original paper (Alfanov and Kurochkin 2011), even though the specimen was named three years earlier. It is clear that Spindler et al. did not trace fingers, but guessed at their presence. They labeled the ‘pectoral girdle’ with a vague arrow, but not the individual elements. Maybe none of this matters, as their study focused on skin coloration.

DGS
(digital graphic segregation), a reconstruction, and a phylogenetic analysis once again pulled data out of an online photo that was overlooked by first hand observers.

References
Alifanov VR and Kurochkin EN 2011. Kyrgyzsaurus bukhanchenkoi gen. et sp. nov., a new reptile from the triassic of southwestern Kyrgyzstan. Paleontological Journal 45(6): 639–647. doi:10.1134/S0031030111060025.
Spindler F, Buchwitz M, Fischer J and Voigt S 2014. Preservation of tetrapod skin in the Triassic Madygen Formation. Conference: 82. Jahrestagung der Paläontologischen Gesellschaft, At Vienna (Austria), Volume: Beiträge zur Paläontologie – Program and Abstracts 32: pp. 76–77.

wiki/Kyrgyzsaurus

 

News on the Origin of Pterosaurs on YouTube

I just uploaded a pterosaur origins video on YouTube. Click here to view it.

Click to view this "Origin of Pterosaurs" video on YouTube.

Click to view this “Origin of Pterosaurs” video on YouTube. 17 minutes long. 

Secondary sexual behavior in Longisquama (and Cosesaurus)

Sure Longisquama had giant plumes
that likely entranced the lay-dees… and/or the gents…

But as the proximal outgroup to the Pterosauria,
and provided with a similar pectoral girdle (sternal complex, strap-like scapulae, quadrant-shaped coracoids, it was a likely flapper, as we talked about earlier here with similar traits in Cosesaurus (Fig. 1)

Figure 1. Cosesaurus flapping - fast. There should be a difference in the two speeds. If not, apologies. Also, there should be some bounce in the tail and neck, but that would involve more effort and physics.

Figure 1. Click to enlarge and animate. Cosesaurus flapping.

Here (Fig. 2) is an animated Longisquama, flapping and with tail wags, which we talked about earlier here.

Figure 2. Click to animate. Longisquama flapping and wagging its tail.

Figure 2. Click to animate. Longisquama flapping and wagging its tail.

With these traits and behaviors basal fenestrasaurs converged with theropods ancestral to birds. In these ways flapping preceded powered flight, in both cases co-opted from secondary sexual behaviors in these highly visual reptiles.

What about those really BIG Rotodactylus tracks?

While virtually all Rotodactylus (Peabody 1948) tracks (digitigrade, proximal phalanges elevated, long stride, narrow gauge manus / wider pes, occasionally bipedal, first digit impresses at tip only, fifth digit impresses far behind the others, extremely variable speed) are the right shape to fit the Cosesaurus  (Ellenberger and Villalta 1974) pes, as we learned earlier here, some Rotodactylus tracks are BIG (4-5 cm length)! That’s way too big for Cosesaurus to fill. So the search is on for something like Cosesaurus, but far bigger and wide ranging (Fig. 1). Rotodactylus tracks have been found across Europe and the western USA and they range across the Early to Middle Triassic.

Figure 1. Scaling a quadrupedal Cosesaurus to the larger Rotodactylus tracks from Haubold 1983.  Quadrant represents center of balance in the closeup foot. Graphic representation of a butt joint is nearby.

Figure 1. Click to enlarge. Scaling a quadrupedal Cosesaurus to the larger Rotodactylus tracks from Haubold 1983. Quadrant represents center of balance in the closeup foot showing how pedal digit 5 made those posterior impressions with a claw mark (Peters 2000). Graphic representation of a butt joint is nearby. The actual Cosesaurus is much smaller than these trackmakers. I enlarged the coracoid on the larger hypothetical trackmakers because they were not bipedal flappers. This configuration of pedal digit 5 is often preserved in basal pterosaurs.

So, after touting the perfect match of Cosesaurus to Rotodactylus tracks (Peters 2000), this is the first time I’ve conformed Cosesaurus to a quadrupedal pose to match these much larger tracks from the Early (=Lower) Triassic (Solling and Röt formations. Scythian/Anisian) of Germany. Haubold (1983) likened Lagosuchus (Maraschus), but  that’s not as good a match as Cosesaurus and Langobardisaurus, which were not so well known or described in the early ’80s.

So, Rotodactylus tracks are not archosaurian, but proto-pterosaurian, fenestrasaurian.

Cosesaurus matched to Rotodactylus from Peters 2000.

Figuure2. Cosesaurus matched to Rotodactylus from Peters 2000.

Haubold listed 4 points that were significant in the development of archosaurs:

  1. “Reduction of the manus as [a] function of bipedalism;
  2. Stride length in relation to width of trackway and pace angulation (small trackway pattern) as a function of semierect to erect gait;
  3. Reduction of pes digits 1 and 5 as a function of tridactylism (this point is unique in Rotodactylus, which impresses  digit 5 far behind the others).
  4. The cross axis of the pes and the outward orientation of the pes axis to the direction of movement. A more rectangular cross axis may demand a mesotarsal joint.”
Cosesaurus and Rotodactylus, a perfect match.

Figure 3. Click to enlarge. Cosesaurus and Rotodactylus, a perfect match. Elevate the proximal phalanges along with the metatarsus, bend back digit 5 and Cosesaurus (left) fits perfectly into Rotodactylus (right).

Rotodactylus tracks show extreme speed variation, which is rare for reptiles, but compliments the higher metabolic niche of fenestrasaurs.

By assigning Rotodactylus tracks to basal bipedal archosaurs, Haubold made the same hopeful mistake that Brusatte et al. (2011) and Niedzwiedzki et al. (2013) made assigning Rotodactylus tracks to  Lagerpeton. These workers hoped it was transitional to dinosaurs, but the match was poor, both phylogenetically and morphologically. The better match is between Cosesaurus and Rotodactylus (Peters 2000, Fig. 3).

So, what about those really BIG Rotodactylus tracks? They were made my really big mostly quadrupedal cosesaurs, evidently. And evidently, only the little cosesaurus were better bipeds, capable of flapping.

Figure 4. Rotodactylus from Haubold adapted from Peabody 1948. Unfortunately, no reptiles have a rotated and reversed pedal digit 5. But note the resemblance of the conjectural trackmaker to Cosesaurus, unknown in 1948.

Figure 4. Rotodactylus from Haubold 1983 adapted from Peabody 1948. Unfortunately, no reptiles have a rotated and reversed pedal digit 5. But note the resemblance of the conjectural trackmaker to Cosesaurus, unknown in 1948. Note: most reptiles while moving do not have all four limbs on the  ground at one time. The elongated pedal digit 5 shown here is likely a drag mark. Size of these prints: between 4 and 5 cm in length, about the size of the examples in figure 1. Note, no claw marks on pedal digit 5.

So, widespread Rotodactylus tracks demonstrate that cosesaurs were widespread. They also appeared in a variety of sizes. While the large ones remained quadrupedal, like ancestral macrocnemids, the small ones became increasingly bipedal. This radiation of tritosaur lizards preceded the radiation of squamates in the Jurassic and later epochs.

References
Brusatte SL, Niedz´wiedzki G and Butler RJ 2011. Footprints pull origin and diversification of dinosaur stem lineage deep into Early Triassic. Proceedings of the Royal Society B, 278, 1107–1113.
Ellenberger P and de Villalta JF 1974. 
Sur la presence d’un ancêtre probable des oiseaux dans le Muschelkalk supérieure de Catalogne (Espagne). Note preliminaire. Acta Geologica Hispanica 9, 162-168.
Haubold H 1983. Archosaur evidence in the Buntsandstein (Lower Triassic). Second Symposium on Mesozoic Terrestrial Ecosystems, Jadwisin 1981. Acta Palaeontologica Polonica 28 (1-2):123-132.
Niedzwiedzki G, Brusatte SL and Butler RJ 2013. Prorotodactylus and Rotodactylus tracks: an ichnological record of dinosauromorphs from the Early–Middle Triassic of Poland. Geological Society, London, Special Publications, first published April 23, 2013. doi 10.1144/SP379.12
Peabody FE 1948.
  Reptile and amphibian trackways from the Lower Triassic Moenkopi formation of Arizona and Utah.  University of California Publications, Bulletin of the  Department of Geological Sciences 27: 295-468.
Peters D 2000. Description and Interpretation of Interphalangeal Lines in Tetrapods.  Ichnos 7:11-41.
wiki/Cosesaurus

This is the image (in Rieppel 1992) that led me astray in 1998.

After I went to visit the holotype of Cosesaurus (Fig. 1) in Barcelona in 1998 (the Monica Lewinsky scandal was going on at the time), I stopped in to visit the original author, Paul Ellenberger, who we discussed earlier here, here and here.  At the time I was naive, inexperienced and untutored, but I did notice the obvious strut emerging anteriorly from the anteriorly expanded ilium (Fig.1). I recognized that was an odd structure. I had never seen anything like it before on other fossils. And nothing like it since.

Cosesaurus prepubis

Figure 1. Cosesaurus prepubis in situ and reconstructed. The strut anterior to the ilium is one of the most distinct features here.  Here is is now interpreted as the stem of the nascent and displaced prepubis.

Confirmation
Ellenberger (1993) noticed the strut as well and also considered it an anterior process of the anterior ilium.

Further Confirmation
Then I noticed Rieppel (1992) described something similar in the T4822 specimen of Macrocnemus and illustrated it (Fig. 2). So, to my mind there was a sister taxon with a similar structure and that made it ‘valid.’ So I accepted and echoed that interpretation in Cosesaurus (Peters 2000). Boy, was I wrong!

Figure 1. Macrocnemus pelvis, specimens identified. Cocked to the right is the Rieppel (1992) interpretation that caused me to think there actually could be an anterior process on the ilium. The process is actually the ventral process, where the pubis connects.

Figure 2. Macrocnemus pelvis. Cocked to the right is the Rieppel (1992) interpretation that caused me to think there actually could be an anterior process on the ilium. The process is actually the ventral process, where the pubis connects. I misinterpreted his pre-actabular process as an anterior process of the ilium blade because Rieppel did not illustrate the actual acetabulum, but he did illustrate the indentation below the reinforcing lateral diagonal ridge also seen in the IVPP specimen (green arrows).

I have regretted it ever since
because that strut in Cosesaurus turned out to be the stem of the Cosesaurus prepubis (Fig. 1), a trait I overlooked in the long line of pterosaurian traits that were otherwise present there.

So I was curious
What did Rieppel (1992) actually see? Here (Fig. 2) I finally found out helped by a more recently discovered and described Macrocnemus, the IVPP V15001 specimen, in which the left pelvis is laid out perfectly in lateral view (Fig. 2) to show exactly what a Macrocnemus pelvis should look like, as opposed to the T 4822 specimen in which the ischium is largely concealed. The IVPP specimen shows the ilium includes a diagonal ridge leading toward the pubis (preacetabulur) process. Rieppel (1992) saw the same ridge in T 4822, but did not illustrate the acetabulum or the other pelvic elements. I have always found that illustration of his confusing, but now I understand it. That’s a relief.

So this is how we fix things in Science.
Correcting mistakes is what we do. I hope to publish this corrected data someday. Currently a manuscript is under review.

References
Ellenberger P 1993. Cosesaurus aviceps . Vertébré aviforme du Trias Moyen de Catalogne. Étude descriptive et comparative. Mémoire Avec le concours de l’École Pratique des Hautes Etudes. Laboratorie de Paléontologie des Vertébrés. Univ. Sci. Tech. Languedoc, Montpellier (France). Pp. 1-664.
Li C, Zhao L-J and Wang L-T 2007. A new species of Macrocnemus (Reptilia: Protorosauria) from the Middle Triassic of southwestern China and its palaeogeographical implication. Science in China D, Earth Sciences 50(11)1601-1605.
Peters D 2000b. A Redescription of Four Prolacertiform Genera and Implications for Pterosaur Phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia 106 (3): 293–336.
Rieppel O 1992. The hind limb of Macrocnemus bassanii (Nopcsa) (Reptilia, Diapsida): development and functional anatomy.