Tiny Vellbergia: a juvenile Prolacerta, not a stem-lepidosauromorph

Sobral, Simoes and Schoch 2020
report on a new, tiny, Middle Triassic reptile, Vellbergia bartholomei (Figs. 1, 3) known from disarticulated skull material. Without creating a reconstruction, they considered Vellbergia a stem-lepidosauromorph different from other stem-lepidosauromorphs.

Figure 1. Vellbergia in situ, original line drawing, DGS colors apple and reconstruction. Note the quadrate break occurs during taphonomic crushing of the curved bone. Scale bar = 5mm. So the skull is about 1.5cm in length, quite tiny.

Figure 1. Vellbergia in situ, original line drawing, DGS colors apple and reconstruction. Note the quadrate break occurs during taphonomic crushing of the curved bone. The nasal, frontal and parietals are incomplete due to their juvenile state. Scale bar = 5mm. So the skull is about 1.5cm in length, quite tiny.

The authors report:
“Important morphological attributes of Vellbergia, most notably the elongate and slender jaw bones, the deeper post-dentary region of the jaw relative to the anterior region, and the far posteriorly reaching maxillary tooth row can be found on some other early diverging diapsid species, such as Prolacerta and Youngina, thus showing these features were retained into the early part of the lepidosauromorph evolutionary history as well.”

Prolacerta.

Figure 2. Prolacerta. Note the relative lengths of the manual and pedal lateral digits.

After phylogenetic analysis
in the large reptile tree (LRT, 1653+ taxa) Vellbergia nests with Prolacerta (Figs. 2, 3). A reconstruction (Figs. 1, 3) demonstrates a close affinity. Based on size and the smooth, incomplete, open sutures of the specimen, this is a juvenile. So the genus ‘Vellbergia’ is a junior synonym. The authors did not include Prolacerta in their published cladogram, but did list it in their suppdata.

Figure 3. Prolacerta and 'Vellbergia' to scale.

Figure 3. Prolacerta and ‘Vellbergia’ to scale.

Taxon exclusion
The Sobral, Simoes and Schoch taxon list did not include enough taxa to produce the basal dichotomy splitting Archosauromorpha from Lepidosauromorpha in the Viséan following their last common ancestor, Silvanerpeton. Prolacertiformes (= Protorosauria) nest in the Archosauromorpha and converge with Lepidosauriformes in many ways, hence the traditional confusion.

The LRT is available online.
Problems like this can be avoided by using ReptileEvolution.com and the LRT to double-check work before submission.


References
Sobral G, Simoes TR and Schoch RR 2020.
A tiny new Middle Triassic stem-lepidosauromorph from Germany: implications fro the early evolution of lepidosauromorphs and the Vellberg fauna. Nature.com Scientific Reports 10, Article number: 2273.

https://doi.org/10.1038/s41598-020-58883-x
https://www.nature.com/articles/s41598-020-58883-x

 

 

Kadimakara: holotype and referred specimen reconstructed as protorosaurs

Lately I found more data on Kadimakara
(Bartholomai 1979 ) than I had ever seen before (Figs 1, 2).

Figure 1. What remains of Kadimakara, above, and the referred specimen, below.

Figure 1. What remains of Kadimakara, above, and the referred specimen, below.

Too little data to add to the LRT,
but everyone seems to agree the prolacertiformes (protorosauria) is the clade these taxa belong to. Until further notice, I tend to agree.

Figure 2. Kadimakara holotype restored with Prolacerta, above. Referred specimen restored below.

Figure 2. Kadimakara holotype restored with Prolacerta, above. Referred specimen restored below.

The two taxa do not seem to be conspecific
even though no two parts overlap.


References
Bartholomai A 1979. New lizard-like reptiles from the Early Triassic of Queensland. Alcheringa. 3 (3): 225–234.

wiki/Kadimakara_australiensis

Ozimek in water: Two new hypotheses

The hyper-slender limbs
of the protorosaur, Ozimek (Fig 1), are unique within the clade Tetrapoda. They are so slender that one wonders how Ozimek was able to move about, with or without the additional burden of that large skull on the end of that long slender neck. We looked at this taxon earlier here and here.

FIgure 1. Ozimek skeleton in vivo. Water and grainy lake bedding are indicated. Neutral buoyancy is one answer to the riddle of those hyper-slender limbs.

FIgure 1. Ozimek skeleton in vivo. Water and grainy lake bedding are indicated. Neutral buoyancy is one answer to the riddle of those hyper-slender limbs.

Originally
(Dzik and Sulej 2016) Ozimek was described as a glider related to Sharoviptyerx, but it is much larger, not related, no lateral membranes are present either in Sharovipteryx or Ozimek, the ribs of Ozimek enclose a cylindrical torso, unlike the flat torso of Sharovipteryx,  and most importantly the limbs in Ozimek are much more slender, relative to those in Sharovipteryx despite being many times larger.

Phylogenetically
the large reptile tree (LRT) nests Ozimek with Prolacerta. There are no gliders in that clade. Jaxtasuchus is another long-necked protorosaur, but it was armored with bony scutes, and was not directly related to Ozimek, yet similar in size. While the metapodials are not compact in any protorosaurs, neither do they spread widely, so the manus and pes of Ozimek were likely narrower (Fig. 1) than originally restored by Dzik and Sulej.

Let’s remember
that gliders may be slender, but their ‘wing struts’ must berobust enough to support their entire weight on extended unsupported limbs, multiple ribs, as in Draco, or extended dermal rods, as in Coelurosauravus. Gliders may also have strong pectoral and pelvic girdles to anchor those gliding limbs. Ozimek will never be described as anything but weak and slender. If it was the size of a fly it might have glided, but at the size of a praying mantis or Sharoviipteryx, that possibility is less likely, let alone at its current size, 3x longer and 9x heavier than Sharovipteryx.

Tanystropheus underwater among tall crinoids and small squids.

Figure 2. Tanystropheus in a vertical strike elevating the neck and raising its blood pressure in order to keep circulation around its brain and another system to keep blood from pooling in its hind limb and tail.

Converging on the long-necked tritosaurs,
Tanystropheus (Fig. 2) and Langobardisaurus (Fig. 3), Ozimek had similar overall proportions,  but with more slender limbs. Tanystropheus is best considered an underwater biped (Fig. 2) based on many geologic clues. Langobardisaurus may have been amphibious, but facultatively bipedal either wet or dry.

Figure 2. Langobardisaurus compared to Ozimek and its sister, Prolacerta.

Figure 3. Langobardisaurus compared to Ozimek and its sister, Prolacerta.

Geological setting
Dzik and Sulej report, “the [Ozimek] fossils under study occur in the one-meter thick lacustrine horizon where the dominantspecies are aquatic or semi-aquatic animals. Shallow freshwater conditions existed at deposition. This taken together with conchostracans occurring within the fauna suggest an abundance of periodic ponding at a lake shore.” Ponds are generally placid bodies of water. Dzik and Sulej report, periodic flooding events transported terrestrial taxa to the ponds during redeposition events. The strata also contain large parasuchians (phytosaurs), large metoposaurs, lungfish and other fish. “Most of the articulated Ozimek gen. nov. specimens were found at the boundary between the red upper and grey lower units of the lacustrine horizon, but not in the grainstone lenses.”

Neutral buoyancy
Ozimek does not have the robust solid ribs that would indicate it was a bottom dweller. The slender limbs were hollow, but not pneumatic, so they were likely filled with bone marrow, according to the authors. In any case, their very slenderness minimizes the amount of air or fat they can contain.

After wrestling with various niche scenarios for Ozimek
the morphological and analog evidence indicates that IF Ozimek was a slow-moving reptile supported by a placid aquatic medium, slender limbs could evolve. The long neck raised and lowered the skull, both for breathing and prey capture. Lateral motions were limited. The long cervical ribs would have kept the neck fairly straight, like a flexible fishing rod. Ozimek was likely a sit and wait predator in shallow ponds. It is difficult to envision it as a giant glider or a terrestrial predator. The limbs were too slender.

Figure 4. Ozimek hitching a ride on top of Metoposaurus.

Figure 4. Ozimek hitching a ride on top of Metoposaurus as a possible parasite, cleaner, or egg predator.

A second hypothesis:
Sometimes when taxa have unusual traits, those develop due to a relationship with other individuals, or even other genera. If Ozimek entertained a remora-like lifestyle, hitched to the top of a giant, slow-moving Metoposaurus (Fig. 4), it would have been protected by the  bulk of its patron and able to feed on leftovers from the giant predator’s meals. Or maybe it fed on parasites attached to Metoposaurus. Or on worms stirred up when Metoposaurus was settling in. Or on Metoposaurus eggs when they were laid. In that role, the limbs of Ozimek would not have needed to remain ambulatory because Metoposaurus would have done the walking. The long fingers and sharp claws (unguals) of Ozimek might have helped anchor it to the back or the flat skull of the giant amphibian.

References
Dzik J and Sulej T 2016. An early Late Triassic long-necked reptile with a bony pectoral shield and gracile appendages. Acta Palaeontologica Polonica 61 (4): 805–823.

 

Czatkowiella: the terror of mixed up puzzle pieces

Fissure fossils
are wonderful in that they are typically uncrushed and readily extracted. They are also horrible in that many bones are fragments, few are attached to each other and worst of all…several sizes, species and genera can get mixed up together. That’s the case with Czatkowiella harae (Fig. 1).

Here’s how Borsuk−Biaynicka and Evans 2009 described the scenario:
“The description that follows is based on isolated and fragmentary bones extracted from a microvertebrate−bearing deposit containing the remains of at least four other small reptiles. Of these, Czatkowiella is overlapped by the archosauriform Osmolskina (Borsuk−Białynicka and Evans 2003) in the upper end of its size range, by Pamelina (Evans 2009) in the middle part of its range, and by Sophineta (Evans and Borsuk− Bialynicka 2009b) at the extreme lower end. This presents something of a challenge in terms of attributing elements, particularly with Osmolskina which is the more closely related taxon. For the smaller diapsids, we have used a combination of fit for individual elements and the general rule that if a bone of the same morphology occurs through a wide size range it is more likely to be Czatkowiella, since there is little variation in jaw size for the two small lepidosauromorphs. The structure of the dentition (using scanning electron microscopy) permits association of tooth−bearing elements, the maxilla then forming a template around which to fit other skull bones.”

Figure 1. Czatkowiella harae bits and pieces here reconstructed as best as possible. Note the size difference here between the large maxilla and the small one.

Figure 1. Czatkowiella harae bits and pieces here reconstructed as best as possible. Note the size difference here between the large maxilla and the small one.

Czatkowiella harae 
(Borsuk−Biaynicka & Evans 2009) Early Triassic ~250 mya, was recently described as a long-necked sister to Protorosaurus Here it nests between Ixalerpeton and Malerisaurus, two taxa that were not tested originally. Several sizes are known, all from disarticulated bone fragments. The number of cervicals is unknown but sister taxa have 8. Hopefully all of the bones assigned to this genus actually belong to this genus.

Figure 2. Borsuk−Biaynicka and Evans tested only Prolacerta and Protorosaurus among the Protorosauria.

Figure 2. Borsuk−Biaynicka and Evans tested only Prolacerta and Protorosaurus among the Protorosauria.

Distinct from Protorosaurus,
the skull of Czatkowiella was longer, lower, flatter and wider. The maxilla ascended in a process just aft of the long naris. The jugal had a stub quadratojugal process. The descending process of the squamosal was gracile and acute. The upper temporal fenestra was smaller. The lateral processes of the parietal were more posteriorly oriented. The cervicals and dorsals were shallower with lower neural spines.

If the two maxillae are indeed conspecific, then the shape of the maxilla changes with ontogeny.

The Borsuk−Biaynicka and Evans cladogram 
suffers from massive taxon exclusion as it nests

  1. Lepidosauromorpha  is wrongly nested as a sister clade to Protorosaurus + Czatkowiella and the rest of the taxa listed below.
  2. The gliderCoelurosaurus, is wrongly nested as a sister clade to Protorosaurus and the rest of the taxa listed below.
  3. Coelurosauravus, is wrongly nested as a sister clade to Ichthyosauria + Thalalattosauria and the rest of the taxa listed below.
  4. Ichthyosauria + Thalalattosauria is wrongly nested as a sister clade to Choristoderes + Turtles  but it is a sister to the clade Sauropterygia.
  5. Choristodera is wrongly nested as a sister clade to Tanystropheus, Macrocnemus, Prolacerta and the rest of the taxa listed below.
  6. Prolacerta is wrongly nested as a sister clade to Trilophosaurus + Rhynchosauria but it is correctly nested as a sister to the Archosauriformes.

Still not sure
how Prolacerta and Protorosaurus get separated in cladograms produced by PhDs.

Borsuk−Biaynicka & Evans 2009 were using outdated taxon sets,
but then, these preceded the publication of the large reptile tree by a few years.

Quick reminder,
Tritosaurs, including Tanystropheus and Macrocnemus are not related to protorosaurs in the large reptile tree despite the many convergent traits.

References
Borsuk−Biaynicka M and Evans S E 2009. A long−necked archosauromorph from the Early Triassic of Poland. Paleontologica Polonica 65: 203–234.

wiki/Czatkowiella

Ozimek volans: homology and analogy

Earlier we looked at the new protorosaur
Ozimek volans (Fig. 1) here and determined by phylogenetic analysis that it was a sister to Prolacerta, not Sharovipteryx.

Today, just a short note
about its homology with Prolacerta and its purported and invalid analogy with the unrelated membrane gliders Sharovipteryx and Cynocephalus.

Figure 1. Ozimek volans compared to its homolog sister, Prolacerta, and to two putative analogs, Sharovipteryx and Cynocephalus, all to scale. Note the lack of climbing claws and the weakness of the limbs and girdles in Ozimek.

Figure 1. Ozimek volans compared to its homolog sister, Prolacerta, and to two putative analogs, Sharovipteryx and Cynocephalus, all to scale. Note the lack of climbing claws and the weakness of the limbs and girdles in Ozimek, adorned here with hypothetical membranes.

Floating is just one niche possibility
based on the weakness of the muscle anchors in Ozimek. I have never seen such skinny arms and legs, so I am at a loss for a suitable niche for it.
I don’t see large climbing claws,
long manual digits, large muscles and their anchors on Ozimek that one finds on Cynocephalus. If it were it otherwise, I might support the gliding hypothesis.
Gliding animals need strong limbs
and muscle anchors not only for supporting their total weight in the air, but also for climbing trees and the momentum shock of both take-off and landing. In this regard, Ozimek appears to be quite a bit weaker than either Cynocephalus or Sharovipteryx. If it was like Sharovipteryx the diameter of the limb bones should have been scaled up to deal with the magnitude greater mass.
Sharovipteryx has elongate ilia and pectoral elements with short arms, plus seven sacrals, all lacking in Ozimek, its putative sister.
Sharovipteryx does not have a lateral membrane
Old and bad reconstructions of Sharovipteryx used to add a membrane between imagined long forelimbs with short fingers and the longer hind limbs. No one has ever seen such a membrane in the fossil. No sisters have such a membrane. Rather a uropatagium trails each hind limb, as in pterosaurs and Cosesaurus. Phylogenetic bracketing adds a pterosaur-like brachiopatagium behind each tiny Sharovipteryx forelimb, but it is likewise not visible in the fossil. The Dzik and Sulej team counts on the validity of the fantasy lateral membrane between the limbs to make their Ozimek a glider. But it was never there in any case.
Figure 1. Dzik and Sulej are so sure that their Ozimek was a spectacular big sister to Sharovipteryx that they gave a model gliding membranes and used the largest disassociated humerus for scale. More likely it was an aquatic animal that did not move around much underwater.

Figure 2. Dzik and Sulej are so sure that their Ozimek was a spectacular big sister to Sharovipteryx that they gave a model gliding membranes and used the largest disassociated humerus for scale. No membranes are present lateral to the pancaked ribs in Sharovipteryx and so this patagium on Ozimek, lacking such ribs, is also based on fantasy.

Prolacerta is also hollow-boned,
and is the sister of Ozimek in the LRT. No tested taxon, including Sharovipteryx, is phylogenetically closer.
Langobardisaurus analogy
Overall, Ozimek looks like a big, skinny Langobardisaurus (Fig. 3).
Figure 2. Langobardisaurus compared to Ozimek and its sister, Prolacerta.

Figure 3. Langobardisaurus compared to Ozimek and its sister, Prolacerta to scale. Structurally, Ozimek was similar to Langobardisaurus, but had much longer, weaker limbs and girdles and despite a long list of similarities, still nested with Prolacerta.

Langobardisaurus had the same long neck
and big skull as seen in Ozimek, but is not related, The girdles are larger and the limbs are more robust in the smaller Langobardisaurus than in the larger Ozimek. So, whatever Langobardisaurus was doing, Ozimek might have been doing, but more slowly, cautiously and secretly, perhaps like a spider.

Protorosaurs and Tritosaurs
appear on opposite sides of the LRT, but closely resemble one another such that macrocnemids and langobardisaurs were both considered protorosaurs (even by me) before the LRT showed macorcnemids and langobardisaurs actually nested with tritosaur lepidosaurs. The convergence is amazing and potentially confusing unless a rigorous analysis is performed. The LRT has been successful in separating such convergent taxa and continues to do so.

References
Dzik J and Sulej T 2016. An early Late Triassic long-necked reptile with a bony pectoral shield and gracile appendages. Acta Palaeontologica Polonica 61 (4): 805–823.

Ozimek volans: long and skinny, but not a glider

Updated a few hours later
with a phylogenetic analysis nesting Ozimek with Prolacerta.

A new and very slender
Late Triassic (230 mya) reptile from lake sediment, Ozimek volans (Dzik and Sulej 2016; ZPAL AbIII / 2512; Figs. 1-3) appears to look like a variety of taxa on both sides of the great divide within the Reptilia: macrocnemids and protorosaurs. Based on the long, thin-walled neck bones, Ozimek was originally considered a possible pterosaur or tanystropheid, but Dzik and Sulej nested it with Sharovipteryx (Fig. 1), the Middle Triassic gliding fenestrasaur, and considered it a big glider (Fig. 3).

Figure 1. Three in situ specimens attributed to Ozimek. The largest humerus (purple) is scaled up from the smaller specimen. These are 80% of full scale when viewed at  72 dpi. To me, that 2012 ulna looks like a tibia + fibula and the 2012 humerus looks like a femur, distinct from the 2512 humerus.

Figure 1. Three in situ specimens attributed to Ozimek. The largest humerus (purple) is scaled up from the smaller specimen. These are 80% of full scale when viewed at  72 dpi. To me, that 2012 ulna looks like a tibia + fibula and the 2012 humerus looks like a femur, distinct from the 2512 humerus.

The large reptile tree
(LRT) does not nest the much larger Ozimek with tiny Sharovipteryx, but with Prolacerta (Fig. 2). While lacking an antorbital fenestra, Dzik and Sulej consider Ozimek an archosauromorph. They also consider Sharovipteryx an archosauromorph.  Like all fenestrasaurs, Sharovipteryx has an antorbital fenestra by convergence with archosauromorpha.

Figure 2. Reconstruction of Ozimek with hands and feet flipped to a standard medial digit 1 configuration and compared to Sharovipteryx and Prolacerta to scale. Note the short robust forelimbs and elongate pectoral elements of Sharovipteryx, in contrast to those in Ozimek.

Figure 2. Reconstruction of Ozimek with hands and feet flipped to a standard medial digit 1 configuration and compared to Sharovipteryx and Prolacerta to scale. Note the short robust forelimbs and elongate pectoral elements of Sharovipteryx, in contrast to those in Ozimek. Compared to Prolacerta the girdles are much smaller, indicating a much smaller muscle mass on the limbs, probably making it a poor walker. Perhaps it floated to support its weight.

Sediment
The authors report on the limestone concretion, “the fossils under study occur in the one-meter thick lacustrine horizon in the upper part where the dominant species are aquatic or semi-aquatic animals. These also include the armored aetosaur Stagonolepis, possible dinosauriform Silesaurus, crocodile-like labyrinthodont Cyclotosaurus, and the predatory rauisuchian Polonosuchus.”

Figure 1. Dzik and Sulej are so sure that their Ozimek was a spectacular big sister to Sharovipteryx that they gave a model gliding membranes and used the largest disassociated humerus for scale. More likely it was an aquatic animal that did not move around much underwater.

Figure 3. Dzik and Sulej are so sure that their Ozimek was a spectacular big sister to Sharovipteryx that they gave a model gliding membranes and used the largest disassociated humerus for scale. More likely it was an aquatic animal that did not move around much underwater due to its weak musculature. The model was built based on crappy reconstructions of Sharovipteryx.

Forelimbs
Dzik and Sulej take the word of Unwin 2000, who did not see forelimbs in Sharovipteryx (and illustrated it with Sharov’s drawing), rather than the reports of Sharov 1971, Gans et al. 1987 and Peters 2000 who did see forelimbs. The latter three authors found the  forelimbs were short with long fingers, distinct from the gracile forelimbs and short fingers found in Ozimek. So, that’s one way to twist the data to fit a preconception. New specimens often get a free pass when it comes to odd interpretations, as we’ve seen before in Yi qi and others.

Manus and pes
In the reconstruction it appears that the medial and lateral digits are flipped from standards. This is both shown and repaired in figure 2.

According to the scale bars
the ZPAL AbIII/2511 specimen is exactly half the size of the ZPAL AbIII/2012 specimen. That issue was not resolved by the SuppData  The humerus shown in the 2012 specimen is not listed in the SuppData. Even so, the authors also ally another large humerus (2028) to Ozimek, and this provides the large scale seen in the fleshed-out model built for the museum and the camera (Fig. 3).

Built on several disassociated specimens
the reconstruction of Ozimek (Fig. 2) is a chimaera, something to watch out for.

Initial attempts at a phylogenetic analysis
based on the reconstruction pointed in three different directions, including one as a sauropterygian based on the illustrated dorsal configuration of the clavicles relative to the coronoids. If the clavicles are rotated so the vernal rim is aligned with the anterior coracoids the dorsal processes line up correctly with the indentations on the scapula (Fig. 2), alleviating the phylogenetic problem.

Lifestyle and niche
Sharovipteryx has an elongate scapula and coracoid, traits lacking in Ozimek. Sharovipteryx also has an elongate ilium and deep ventral pelvis, traits lacking in Ozimek. The limbs are so slender in Ozimek, much more so than in the much smaller Sharovipteryx, that it does not seem possible that they could support the large skull, long neck and long torso in the air – or on the ground. This is a weak reptile, likely incapable of rapid or robust locomotion. So instead of gliding, or even walking, perhaps Ozimek was buoyed by still water. Perhaps it moved its spidery limbs very little based on the small size of the available pectoral and pelvic anchors for muscles, despite those long anterior caudal transverse processes. Those might have been more useful at snaking a long thin tail for propulsion.

If we use our imagination,
perhaps with a large oval membrane that extended from the base of the neck to fore imbs to hind limbs Ozimek might have been like a Triassic water lily pad, able to dip its skull beneath the surface seeking prey, propelled by a flagellum-like tail. Not sure how else to interpret this set of specimens.

References
Dzik J and Sulej T 2016. An early Late Triassic long-necked reptile with a bony pectoral shield and gracile appendages. Acta Palaeontologica Polonica 61 (4): 805–823.

wiki/Ozimek (in Polish)

The Protorosaurus Wastebasket

Back in  2009
Gottmann-Quesada and Sanders produced the first comprehensive study of Protorosaurus (Meyer 1832, Tatarian, Late Permian) in over a hundred years. Protorosaurus was one of the first fossil reptiles ever described (Spener 1710). According to Gottmann-Quesada and Sanders, “large numbers” of Protorosaurus specimens have been added to collections, Only one (Fig. 6), they say, preserves a complete skull.

Unfortunately 
Gottmann-Quesada and Sanders lumped several disparate genera under the genus Protorosaurus. Evidently the genus Protorosaurus has become a phylogenetic ‘wastebasket’ for a variety of protorosaurs and other reptiles in the Late Permian.

Figure 1. The lectotype of Protorosaurus identified by Gottmann and Sanders. Note the small size.

Figure 1. The lectotype of Protorosaurus identified by Gottmann and Sanders. See below for a reconstruction and comparisons.

Unfortunately
Gottmann-Quesada and Sanders consider Diapsida the ancestral clade for Archosauromorpha and Lepidosauromorpha. The large reptile tree (now 614 taxa) does not support that old paradigm. Their analysis is based on the data set of Dilkes (1998) “because he was the first to propose a paraphyletic Prolacertiformes.” Unfortunately for Gottmann-Quesada and Sanders the Dilkes study focuses on the basal rhynchosaur, Mesosuchus, a taxon completely unrelated to Protorosaurus in the large reptile tree. The Gottmann and Sanders tree is similar to that of Nesbitt et al. (2015) we just looked at with regard to Azendohsaurus.

Relying on someone else’s tree
has become more and more of a headache for paleontologists who keep chasing their tails with untenable and falsified cladograms.

Figure 1. Results of the most inclusive phylogenetic analysis of early archosauromorphs. Note the separation of Protorosaurus and Prolacerta, the nesting of Protorosaurus with Megalancosaurus and the use of suprageneric taxa. This tree suffers greatly from too few specific taxa.

Figure 2. Results of the most inclusive phylogenetic analysis of early archosauromorphs by Gottman-Queseda and Sanders. Note the separation of Protorosaurus and Prolacerta, the nesting of Protorosaurus with Megalancosaurus and the use of suprageneric taxa. This tree suffers greatly from too few specific taxa. Pamelaria is misspelled Palmeria, the least of the many problems with this tree.

In contrast,
the large reptile tree finds that Archosauromorpha and Lepidosauromorpha are basal reptile clades (with Gephyrostegus bohemicus of the Westphalian) nesting as a closest known sister to that as yet unknown, but close to Eldeceeon, a Viséan ancestor. The Diapsida, therefore, turns out to be diphyletic with lepidosaurs on one branch and archosaurs on the other, related to each other only through G. bohemicus.

Figure 1. The Protorosauria. nests two Prolacerta specimens and three Protorosaurus specimens, along with a scattering of others.

Figure 3. The Protorosauria. nests two Prolacerta specimens and three Protorosaurus specimens, along with a scattering of others. Click to enlarge.

Getting back to Protorosaurs (taxa nesting with Protorosaurus)
they nest basal to the archosauriformes and both are derived from terrestrial younginiformes. Former  protorosaurs, like Macrocnemus and Tanystropheus now nest within the Lepidosauria between Rhynchocephalia and Squamata. This new paradigm has to start sinking in and permeating the paleo world.

Gottmann-Quesada and Sanders used
144 characters, 15 hand-picked terminal ungroup taxa, two hand-picked outgroup taxa. Bootstrap and Bremer values were considered “low.”

That compares to
228 characters and 610 taxa in the completely resolved large reptile tree with generally high to very high Bootstrap values throughout. All subsets remain fully resolved. That means deletion of taxa do not affect the remaining tree topology in the large reptile tree. And all derived taxa are preceded by series of taxa with gradually accumulating character traits — unlike other traditional trees, like the Dilkes/Gottman-Quesada and Sanders tree

Figure x. Two taxa assigned to Protorosaurs by Gottmann-Quesada and Sanders. The lower one is the new lectotype. The upper one nests closer to Pamelaria and is clearly not congeneric.

Figure 4. Two taxa assigned to Protorosaurus by Gottmann-Quesada and Sanders. The lower one is the new electrotype (Fig. 1). The upper one nests closer to Pamelaria and is clearly not congeneric. See how reconstructions help? Some of this is not immediately apparent in the fossils themselves.

The Gottmann-Quesada and Sanders analysis (Fig. 2) 
nested Protorosaurus with the drepanosaurid Megalancosauru and away from Prolacerta. That should have been noticed as a red flag. One can only wonder how poorly these taxa were scored for such nestings to happen.

The large reptile tree nested Protorosaurus with Prolacerta and other protorosaurs.
Which analysis would you have more confidence in?

Figure 3. The putative Protorosaurus juvenile (in situ) is actually a large Permian Homoeosaurus.

Figure 5. The putative Protorosaurus juvenile (in situ) is actually a large Permian Homoeosaurus.

A juvenile Protorosaurus?
Gottmann-Quesada and Sanders considered the Late Permian reptile IPB R 535 (Institut für Paläontologie, Unversität, Bonn) the first and only juvenile Protorosaurus.  I added it to the large reptile tree and recovered it rather securely as a large Homoeosaurus, a long-lived taxon otherwise known from Jurassic strata. This specimen adds to the small but growing number of known Permian lepidosaurs,

Figure 2. The WMsN-P47 specimen assigned to Protosaurus, but is closer to Pamelaria.

Figure 6. The WMsN-P47 specimen assigned to Protosaurus, but is closer to Pamelaria. The scapulocoracoid is not fused, as proven by one scapula flipped so that the dorsal rim is in contact with its corticoid. I’ve always wondered about that inconsistency. A hi-rez image and DGS solved that problem.

The WMsN-P47 specimen that Gottmann-Quesada and Sanders assigned to Protorosaurus (Fig. 4) is actually closer to Pamelaria (see figure 7) in the large reptile tree. This specimen is too distinct to be lumped with Protorosaurus.

Gottmann-Quesada and Sanders reported
that Protorosaurus has seven cervicals. I found evidence for eight without seeing the fossil first hand. DGS techniques enable the identification and reconstruction of skull elements in the pre-Pamelaria specimen (Fig. 6) previously considered too difficult to attempt.

Figure 5. Several protorosaurs to scale including Pamelaria, Protorosaurus, Prolacerta, Malerisaurus, Boreopricea and Jaxtasuchus. Click to enlarge.

Figure 7. Several protorosaurs to scale including Pamelaria, Protorosaurus, Prolacerta, Malerisaurus, Boreopricea and Jaxtasuchus. Click to enlarge.

It is unfortunate
that Gottmann-Quesada and Sanders lumped all of their Protorosaurus specimens together when there is clearly a diversity of morphologies and sizes here. They did not feel the need to perform a phylogenetic analysis on the individual specimens or to create more than a single skull reconstruction (Fig. 8).

And I apologize
for earlier reconstructions created out of more than one specimen. I should never have created chimaeras. They really mess up phylogenetic analyses.

Figure 6. GIF animation of the NMK S 180 specimen assigned to Protorosaurus by Gottmann and Sanders. I was able to tease out certain palatal bones ignored by them.

Figure 8. GIF animation of the NMK S 180 specimen assigned to Protorosaurus by Gottmann and Sanders. I was able to tease out certain palatal bones ignored by them. Reconstruction by Gottman and Sanders.

Gottmann-Quesada and Sanders mention Peters (2000)
due to that paper adding pterosaurs to the list of then considered prolacertiformes (later corrected in Peters 2007). They report, “this analysis suffers from over interpretation of poorly preserved fossils.” This is more professional BS. Either one look or rigorous examination of the fossils studied in Peters (2000) reveals that all include soft tissue and preserve every bone in articulation, which is the definition of “exquisitely preserved.”

I can only imagine
that, like Hone and Benton (2007, 2009) Gottmann-Quesada and Sanders felt the need to cite relevant literature, but shuddered at the prospect of actually dealing with non-traditional results. To their point on interpretation, mistakes were made in Peters (2000), some from under-interpretation and some from naiveté. That is why I submitted corrections (which were rejected), including Peters 2007 (which was published as an abstract). ReptileEvolution.com/cosesaurus.htm and links therein publicly repair the errors found in Peters (2000).

Gottmann-Quesada and Sanders report
the only trait uniting the Prolacertiformes [protorosaurs] are the elongated mid-cervical vertebrae. Unfortunately this trait also appears in several other clades within the Reptilia. The large reptile tree likewise did not find a single common character in the protosaurs. As in so many other clades it is the suite of traits that lump and separate them.

References
Gottmann-Quesada A and Sander PM 2009. A redescription of the early archosauromorph Protorosaurus speneri Meyer, 1832, and its phylogenetic relationships. Palaeontographica Abt. a 287: 123-220.
Meyer H von 1832. Palaeologica zur Geschichte der Erde und ihrer Geschöpfe. Verlag Siegmund Schmerber, Frankfurt a.M. 560 pp.
Peters D 2000. A redescription of four prolacertiform genera and implications for pterosaur phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia 106: 293-336
Peters D 2007. The origin and radiation of the Pterosauria. Flugsaurier. The Wellnhofer Pterosaur Meeting, Munich 27.
Seeley K 1888. Research on the structure, organisation and classification of the fossil Reptilia 1. On the Protorosaurus speneri (von Meyer). Philosophical Transactions of the Royal Society, London B 178, 187–213.
Spener CM 1710. Disquisitio de crocodilo in lapide scissilli expresso, aliisque Lithozois. Misc. Berol. ad increment. sci., ex scr. Soc. Regiae Sci. exhibits ed. IL92-110.

Triassic gastric pellet semi-reconstructed, better this time…

A while back
Dalla Vecchia, Wild and Muscio (1989) described a small pellet (MFSN 1891, Fig. 1) of Late Triassic bones from the Dolomia di Forni Formation of Firuli (NE Italy) as a small jumble of pterosaur bones. They tentatively referred it to Preondactylus, the only pterosaur known at the time from that formation. This was an early work for all three paleontologists.

Following the original paper
Earlier I attempted a reconstruction of the elements based on the pterosaur model. I recognized then that it didn’t turn out too well. I was working from the original drawings. Now new data has been published and a new hypothesis has been put forth that makes much more sense.

Figure 1. Several views of the Triassic gastric pellet formerly considered pterosaurian, but now considered langobaridsaurian. Elements from a surface photo, a microCT scan of the opposite side still buried in matrix, and DGS colors. Not all bones have been colored here.

Figure 1. Several views of the Triassic gastric pellet formerly considered pterosaurian, but now considered langobaridsaurian. Elements from a surface photo, a microCT scan of the opposite side still buried in matrix, and DGS colors. Not all bones have been colored here, but employed colors are assembled in figure 2. The long cervical at upper left is 1 cm long. So is the scale bar. The pellet is about 5 cm wide.

Recently 
Holdago et al. (2015) redescribed the pellet in much greater detail using microCT acquisition. They concluded “The best candidate for the pellet is not a pterosaur, but a protorosaurian like Langobardisaurus.  Therefore, the skeletal remains could belong to a still unknown small reptile with procoelous dorsal vertebrae, rather elongate and probably procoelous cervical vertebrae with low neural arch and spine, filiform cervical ribs, at least some dicephalous dorsal ribs, elongated and hollow limb bones, and no osteoderms.”

They did not attempt a reconstruction,
so I do so here (Fig. 2) following the hypothesis that the elements belong to a langobardisaur (contra Holdgago, et al., not a protorosaur but a tritosaur lepidosaur).

Figure 2. The elements of MFSN 1891 assembled to form a langobardisaur in a bipedal pose.

Figure 2. The elements of MFSN 1891 assembled to form a langobardisaur in a bipedal pose. Some langobardisaurs have a very long neck, slender limbs and a short tail. Lots of guesswork here.

Lots of guesswork here. 
Everything is tentative. The toes could be ribs. Lots of slivers and scraps left over. More complete langobardisaurs (Fig. 3) have 8 cervicals, but they are related to tanystropheids, with 13 cervicals. Renesto et al. (2002) considered langobardisaurs as likely facultative bipeds in the manner of the many extant facultative bipedal lizards, all with sprawling hind limbs.

Langobardisaurus tonneloi reconstructed. Note the cosesaur-like pectoral girdle.

Figure 3. Langobardisaurus tonneloi reconstructed. Note the cosesaur-like pectoral girdle.

MFSN 1891 needs to be dissembled
in high resolution, then reassembled like a puzzle. I’d like to help if possible. Here (Fig. 2) is a first draft lo rez example leading to others of greater detail in the future. Worthwhile taking another look at the pes (Fig. 3) which greatly resembles a basal pterosaur pes with that elongate p5.1. It resembles a pterosaur pes because these two taxa are related (Peters 2000).

Figure 6. Click to view full scale on a 72 dpi screen. Tanystrachelos compared to the gastric pellet lepidosaur.

Figure 4. Click to view full scale on a 72 dpi screen. Tanystrachelos compared to the gastric pellet lepidosaur. The large hemal arches on the gastric pellet are the genesis of the paddle-like hemal arches on Tanytrachelos and Tanystropheus.

Compared to the tritosaur Tanytrachelos (Fig. 4)
the gastric pellet reptile has a similar number of cervicals, but longer limbs and longer cervicals. Are we seeing the origin of Tanystropheus (Fig. 5) here? Or a hatchling? The large hemal arches appear to have homologs in Tanytrachelos and Tanystropheus.

Tanystropheus and kin going back to Huehuecuetzpalli.

Figure 5. Tanystropheus and kin going back to Huehuecuetzpalli. Two scales here, one yellow, one white.

Then we have Fuyuanssaurus, 
a tiny tanystropheid (Fig. 6) about twice the size of the gastric pellet reptile. Unfortunately we don’t know if it was long-legged or not. Notably the skull elements of Fuyuansaurus, which we looked at earlier here were all quite slender. This is the model we should use for the gastric pellet lizard until data suggests another model.

Figure 2. Click to enlarge. Reconstruction of Fuyuanasaurus. Fraser et al. identified a strange circular object as the pubis, but no sister taxa have a circular pubis. Here it is tentatively ID'd as an egg because a standard pubis is found nearby.

Figure 6. Click to enlarge. Reconstruction of Fuyuanasaurus. Fraser et al. identified a strange circular object as the pubis, but no sister taxa have a circular pubis. Here it is tentatively ID’d as an egg because a standard pubis is found nearby.

References
Dalla Vecchia FM, Wild R and Muscio G 1989. Pterosaur remains in a gastric pellet from Upper Triassic (Norian) of Rio Seazza valley (Udine, Italy). Gortania 10: 121–132.
Holgado B, Dalla Vecchia FM, Fortuny J, Bernardini F and Tuniz C 2015. A Reappraisal of the Purported Gastric Pellet with Pterosaurian Bones from the Upper Triassic of Italy. PLoS ONE 10(11): e0141275. doi:10.1371/journal.pone.0141275
Peters D 2000. A Redescription of Four Prolacertiform Genera and Implications for Pterosaur Phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia 106 (3): 293–336.
Renesto S, Dalla Vecchia FM, Peters D. 2002. Morphological evidence for bipedalism in the Late Triassic prolacertiform reptile Langobardisaurus. In: Gudo M, Gutmann M, Scholz J, editors. Concepts of functionalengineering and constructional morphology: biomechanical approaches on fossil and recent organisms. Senckenb Lethaea 82(1): 95–106.

 

Pamelaria, a large, long-necked protorosaur

Pamelaria dolichotrachela (Sen 2003) Middle Triassic, is the largest known prolacertiform (= protorosaur) and it has the longest neck of them all. (Please, remember Tanystropheus is a tritosaur lizard, not a prolacertiform/protorosaur).

Pamelaria, an long-necked protorosaur related to Protorosaurus.

Figure 1. Pamelaria, an long-necked protorosaur related to Protorosaurus.

Distinct from Protorosaurus, the skull of Pamelaria was relatively smaller with a shorter rostrum and smaller teeth. The nares were reported as confluent, and indeed they may be so, but that area of the skull was poorly preserved. The premaxilla was more robust. The postorbital was waisted at the postfrontal process. The quadrate was nearly vertical. The lacrimal was larger. The orbit was taller than long. The palate included smaller openings for the choanae due to a wider set of vomers. The parasphenoid was larger. The mandible elements were all shorter, including the teeth. The ventral rim of the mandible was straighter.

The cervicals were each longer. The tail was relatively shorter. The dorsal ribs were longer and more robust, enclosing a larger gut.

The scapula was taller and not fused to the coracoid. The forelimbs were more robust. Digits 3 and 4 were nearly equal in length. Ungual 1 was deeper proximally.

The pelvis was relatively shorter with an excavated ventral rim. The fibula was bowed away from the tibia. The foot was more robust with shorter digits. Metatarsals 2 and 3 were aligned with the base of ungual 1.

Sen (2003) considered Pamelaria a carnivore. With a bulkier body, smaller head and longer neck, Pamelaria must have looked like a sauropod, except with sprawling, lizard-like limbs (reminiscent of the earliest reconstructions of sauropods!). The small teeth and large gut suggest an herbivorous diet.

Pamelaria was a derived taxon leaving no known descendants. I see it as convergent to dinocephalians in respect to the torso, tails and limbs.

As always, I encourage readers to see specimens, make observations and come to your own conclusions. Test. Test. And test again.

Evidence and support in the form of nexus, pdf and jpeg files will be sent to all who request additional data.

References
Sen K 2003. Pamelaria dolichotrachela, a new prolacertid reptile from the Middle Triassic of India. Journal of Asian Earth Sciences 21: 663–681.

What is Azendohsaurus?

Updated May 15, 2015 to reflect the new nesting of Azendohsaurus back with Trilphosaurus.

Azendohsaurus has bounced around the reptile family tree.
Azendohsaurus was originally described by Dutuit (1972) as an ornithischian dinosaur on the basis of two teeth and a dentary fragment. Gauffre (1993) found a bit more of the dentary and described Azendohsaurus as a prosauropod. Flynn et al. (2010) found a relatively complete skeleton in Madagascar, but only the skull has been published to date. Flynn et al. (2010) considered Azendohsaurus the “nearest archosauromorph outgroup to the archosauriformes (but then they also ascribe to the false nesting of Trilophosaurus and rhynchosaurs as sisters to Archosauriformes).

Figure 1. The skull and palate of Azendohsaurus, a sister to Trilophosaurus. 

Figure 1. The skull and palate of Azendohsaurus, a sister to Trilophosaurus.

Nesting Azendohsaurus on The Large Reptile Family Tree
Here, phylogenetic analysis nests Azendohsaurus with Trilophosaurus, a lepidosaur (Fig. 2).

Figure 2. DGS applied to the skull of Azendohsaurus. Note the new addition of a lateral naris, not previously noted.

Figure 2. DGS applied to the skull of Azendohsaurus. Note the new addition of a lateral naris, not previously noted. Compared to sister taxa, both the ascending processes of the premaxilla and maxilla are very tall. 

Teeth
In Trilophosaurus two rows of teeth are present but fused to form wide teeth with two roots. Azendohsaurus is similar with two rows of large teeth (on the maxilla and palatine) growing close to one another. Flynn et al. (2010) reported that the palatine was reversed from what is shown in figures 1 and 2, with a toothless anterior maxillary process.

Convergence with Sauropods
The elevation and reduction of the naris converges with that of sauropods and gives Azendohsaurus it’s sauropod-like look. Flynn et al. (2010) reported, “Azendohsaurus and numerous basal sauropodomorph dinosaur taxa share an array of convergently acquired features associated with herbivory, including tooth denticles, expanded tooth crowns, a downturned dentary and the articular located at the ventral margin of the mandible.”

Nesbitt et al. 2013. reported on the post-crania:
“Azendohsaurus madagaskarensis possessed an elongated neck, short tail, and stocky limbs. The manus and pes have unexpectedly short digits, terminating in large, recurved ungual phalanges. Together with the skull, knowledge of the postcranial skeleton elevates A. madagaskarensis to another highly apomorphic and bizarre Triassic archosauromorph.”

This description is both distinct and similar to Trilophosaurus.

References
Dutuit J-M 1972. Découverte d’un Dinosaure ornithischien dans le Trias supérieur de l’Atlas occidental marocain. Comptes Rendus de l’Académie des Sciences à Paris, Série D 275:2841-2844.
Flynn JJ, Nesbitt, SJ, Parrish JM, Ranivoharimanana L and Wyss AR 2010. A new species of Azendohsaurus (Diapsida: Archosauromorpha) from the Triassic Isalo Group of southwestern Madagascar: cranium and mandible”. Palaeontology 53 (3): 669–688. doi:10.1111/j.1475-4983.2010.00954.x
Gauffre, F-X 1993. The prosauropod dinosaur Azendohsaurus laaroussii from the upper Triassic of Morocco. Palaeontology 36(4):897-908. Gauffre pdf online
Nesbitt, S, Flynn J, Ranivohrimanina L, Pritchard A and Wyss A 2013. Relationships among the bizarre: the anatomy of Azendohsaurus madagaskarensis and its implications for resolving early archosauromroph phylogeny. Journal of Vertebrate Paleontology abstracts 2013.