Tiny enigmatic Feralisaurus nests with a giant bizarre sister

Today
another paleo-enigma is confidently nested after those who had direct access to the specimen gave up on it. The authors admitted they didn’t know what they had.

According to the Cavicchini, Zaher and Benton 2020 abstract:
“Phylogenetic analyses, although showing generalized weak support, retrieved Feralisaurus within Neodiapsida or stem-group Lepidosauromorpha: its morphology supports the latter hypothesis.”

The authors gave up because they excluded pertinent taxa.
The authors did not reference the large reptile tree (LRT, 1745+ taxa; subset Fig. 6), which minimizes taxon exclusion. Here, having a quantity of taxa really paid off.

The ‘enigmatic Otter Sandstone diapsid’ from 2017 finally has a name:
Feralisaurus corami (Cavicchini, Zaher and Benton 2020; Coram, Radley and Benton 2017; BRSUG 29950-12; Middle Triassic). Cavicchini, Zaher and Benton 2020 provided µCT scans (Fig. 1) from which a reconstruction was created and scored using DGS (digital graphic segregation). They nested aquatic Feralisaurus between the gliding reptile, Coelurosauravus and basal lepidosaurs + another gliding reptile, Icarosaurus (Fig. 5).

Figure 1. Feralisaurus in situ and reconstructed. CT scans (hard colors) from Cavicchini, Zaher and Benton 2020. DGS (soft colors) added here.

Figure 1. Feralisaurus in situ and reconstructed. CT scans (hard colors) from Cavicchini, Zaher and Benton 2020. DGS (soft colors) added here. Shown about 20% larger than life size. Here more cervicals are present, a sternum is present, The tip of the posterior interclavicle is identified along with several skull bones. Creating or attempting to create a reconstruction is the second half of the DGS method and, as you can see, it is so important in understanding all enigmatic specimens.

After DGS, reconstruction and re-scoring in the LRT
(Fig. 6), tiny, flat-headed Feralisaurus nests with the giant, flat-headed macrocnemid tritosaur lepidosaur Dinocephalosaurus. Both are derived from the PIMUZ 2477 specimen of Macrocnemus, nesting apart from the other tested Macrocnemus specimens (Fig. 6).

Figure 6. Dinocephalosaurus skull in situ.

Figure 2. Dinocephalosaurus skull in situ. The maxillary palatal shelf? is not colored here.

The dorsal nares in both Feralisaurus and Dinocephalosaurus
may have emitted stale air as a bubble net to corral fish swimming overhead (Fig. 3), analogous to the feeding strategy of baleen whales. The larger the size, the longer the neck, the greater storage for this stale air. Perhaps that is what drove the transition from tiny Feralisaurus to the much larger Dinocephalosaurus.

Dinocephalosaurus in resting, feeding and breathing modes.

Figure 3. Dinocephalosaurus in resting, feeding and breathing modes. In breathing mode the throat sac would capture air that would not be inhaled until the neck was horizontal at the bottom of the shallow sea. Orbits on top of the skull support this hypothesis.

Coram, Radley and Benton 2017
presented (then nameless) Feralisaurus as a “small diapsid reptile, possibly, pending systematic study, a basal lepidosaur or a protorosaurian.” According to Coram et al. “The Middle Triassic (Anisian) Otter Sandstone was laid down mostly by braided rivers in a desert environment.” 

What was visible to the unaided eye
in the 2017 report suggested a relationship to the basal lepidosaur, Megachirella. The 2020 µCT scans of Feralisaurus data corrected earlier errors. Here (Fig. 4) is the first reconstruction of Feralisaurus based on DGS. The new data nests it with Dinocephalosaurus, despite the great difference in size, the differences in morphology and the niche relocation from braided river in a desert to ocean.

Figure 2. Feralisaurus reconstructed in lateral and dorsal views.

Figure 4. Feralisaurus reconstructed in lateral and dorsal views.

Although Cavicchini, Zaher and Benton 2020 scanned the specimen
those scans were not enough to clarify phylogenetic issues. The authors not only excluded its LRT sister, Dinocephalosaurus, but hundreds of other taxa that would have split basal Reptilia into the new Archosauromorpha and the new Lepidosauromorpha (Fig. 5) as in the LRT. This basal dichotomy following Silvanerpeton in the Viséan (or earlier) is recovered when sufficient pertinent basal taxa are added to a reptile cladogram. Apparently no one wants to add hundreds of taxa when ready-made smaller invalid cladograms are available.

Figure 3. Cladogram from Cavicchini, Zaher and Benton 2020, colors added based on the LRT showing how massive taxon exclusion shuffles convergent taxa.

Figure 5. Cladogram from Cavicchini, Zaher and Benton 2020, colors added based on the LRT showing how massive taxon exclusion shuffles convergent taxa.

The Cavicchini, Zaher and Benton 2020 cladogram
shows what happens when you include too few taxa. As in prior analyses of similar deficit, this one (Fig. 5) shuffles members of the new Archosauromorpha and new Lepidosauromorpha. The Cavicchini, Zaher and Benton 2020 cladogram nests the glider Icarosaurus, with the large plant-eating Trilophosaurus. Note how easily rhynchosaurs (Lepidosauromorpha) nest with protorosaurs (Archosauromorpha) here splitting Protorosaurus from Prolacerta. The LRT adds enough taxa to nest rhynchosaurs with rhynchocephalians and Protorosaurus with the other protorosaur, Prolacerta.

Figure 4. Subset of the LRT with the addition of Feralisaurus (yellow).

Figure 6. Subset of the LRT with the addition of Feralisaurus (yellow).

Feralisaurus was a tiny river predator,
smaller than the PIMUZ 2477 Macrocnemus. Dinocephalosaurus was a giant marine predator with a longer neck, shorter limbs and other extreme traits.

Once again, phylogenetic miniaturization
appears to have preceded a novel morphology.

The apparent lack of maxillary bone
in Feralisaurus (perhaps due to taphonomy) continues as a likely antorbital fenestra in Dinocephalosaurus. What was considered a lateral panel of the maxilla could instead be a maxillary palatal shelf showing through the antorbital fenestra. The broad muzzle and genuine flatness of the Feralisaurus skull continues in Dinocephalosaurus.

Figure 7. Feralisaurus is a phylogenetic miniature nesting basal to Dinocephalosaurus in the LRT.

Figure 7. Feralisaurus is a phylogenetic miniature nesting basal to Dinocephalosaurus in the LRT.

Bottom line: 
Create reconstructions using DGS. Add taxa. These methods solve problems. Workers traditionally say first-hand observation is essential. This case proves, once again, first-hand observation is not essential. A cladogram as large as the LRT is essential.


References
Caviccnini I, Zaher M and Benton MJ 2020. An enigmatic neodiapsid reptile from the Middle Triassic of England. Journal of Vertebrate Paleontology e1781143 (18 pages)
Coram RA, Radley JD and Benton MJ 2017. The Middle Triassic (Anisian) Otter Sandstone biota (Devon, UK): review, recent discoveries and ways ahead. Proceedings of the Geologists’ Association in press. http://dx.doi.org/10.1016/j.pgeola.2017.06.007

http://reptileevolution.com/dinocephalosaurus.htm

https://pterosaurheresies.wordpress.com/2017/07/27/what-is-the-enigmatic-otter-sandstone-middle-triassic-diapsid/

wiki/Feralisaurus
wiki/Dinocephalosaurus

Lepidosaurian epipterygoids in basal pterosaurs

In 1998 lepidosaurian epipterygoids
were found in the basal lepidosaur tritosaur, Huehuecuetzpalli (Fig. 1, Reynoso 1998; slender magenta bones inside the cheek area).

Figure 2. Huehuecuetzpalli has a tall, narrow epipterygoid, as in other lepidosaurs, and just a pore of an antorbital fenestra in the maxilla.

Figure 1. Huehuecuetzpalli has a tall, narrow epipterygoid, as in other lepidosaurs, and just a pore of an antorbital fenestra in the maxilla.

About two years ago
previously overlooked lepidosaurian epipterygoids were identified here in a more derived lepiodaur tritosaur, Macrocnmeus (Fig. 2, slender green bones in the orbit area) for the first time.

Figure 1. Macrocnemus fuyuanensis (GMPKU-P-3001) in situ and as traced by the original authors, (middle) flipped with colors applied to bones, and (above) bone colors moved about to form a reconstruction. Darker yellow and darker green are medial views of premaxilla and maxilla. Note the long ascending process of the premaxilla and the palatal elements seen through the various openings all overlooked by those with firsthand access to the fossil. Epipterygoids are lepidosaur synapomorphies not present in protorosaurs.

Figure 2. Macrocnemus fuyuanensis (GMPKU-P-3001) in situ and as traced by the original authors, (middle) flipped with colors applied to bones, and (above) bone colors moved about to form a reconstruction. Darker yellow and darker green are medial views of premaxilla and maxilla. Note the long ascending process of the premaxilla and the palatal elements seen through the various openings all overlooked by those with firsthand access to the fossil. Epipterygoids are lepidosaur synapomorphies not present in protorosaurs.

Until now,
no one has ever positively identified lepidosaurian (slender strut-like) epipterygoids in a pterosaur. In the large reptile tree (LRT, 1737+ taxa) and the large pterosaur tree (LPT, 251 taxa) Bergamodactylus (MPUM 6009) nests as the basalmost pterosaur. Here is the skull in situ with DGS colors applied, as traced by Wild 1978 (above), and reconstructed in lateral and palatal views (below) based on the DGS tracings.

Figure 3. Bergamodactylus skull in situ and reconstructed. Wild 1978 tracing above.

Figure 3. Bergamodactylus skull in situ and reconstructed. Wild 1978 tracing above. Note the break-up of the jugal. Note the fusion of the ectopterygoids with the palatines producing ectopalaatines.

The lepidosaurian epipterygoids of Bergamodactylus
(slender bright green struts in the cheek/orbit area in figure 3), or any pterosaur over the last 200 years, are identified here for the first time, further confirming the lepidosaurian status of pterosaurs (Peters 2007, the LRT). Sorry I missed these little struts earlier. When you don’t think to look for them, you can overlook them.

Figure 5. Eudimorphodon epipterygoids (slender green struts).

Figure 4. Eudimorphodon epipterygoids (slender green struts).

Now you may wonder how many other pterosaurs
have overlooked epipterygoids? A quick look at Eudimorphodon reveals epipterygoids (Fig. 4, bright green struts). Other Triassic pterosaurs include:

  1. Austriadactylus SMNS 56342: slender strut present
  2. Austriadactuylus SC 332466: slender strut present
  3. Raeticodactylus : slender strut is present (identified on link as a stapes)
  4. Preondactylus: slender strut present
  5. Dimorphodon: amber strut over squamosal (Fig. 5 in situ image), 
  6. Seazzadactylus MFSN 21545: slender struts present, tentatively identified by Dalla Vecchia 2019, but as more than the slender struts they are) (Fig. 6).
The skull of Dimorphodon macronyx BMNH 41212.

Figure 5. The skull of Dimorphodon macronyx BMNH 41212. Above: in situ. Middle: Restored. Below: Palatal view. The slender yellow strut on top of the red squamosal in situ is a likely epipterygoid.

Figure 6. Seazzadactylus from Dalla Vecchia 2019. Here the epipterygoid struts are more correctly and less tentatively identified.

Figure 6. Seazzadactylus from Dalla Vecchia 2019. Here the epipterygoid struts are more correctly and less tentatively identified.

Hard to tell in anurognathids
where everything is crushed and strut-like. Hard to tell in other pterosaurs because the hyoids look just like epipterygoids. Given more time perhaps more examples will be documented that are obvious and irrefutable.

Added a few days later:

Added Figure. Here's the Triebold specimen of Pteranodon (NMC41-358) with epipterygoid splinters in bright green.

Added Figure. Here’s the Triebold specimen of Pteranodon (NMC41-358) with epipterygoid splinters in bright green.

Here’s the Triebold specimen of Pteranodon
(NMC41-358, added figure) with epipterygoid splinters in bright green. So start looking for the epipterygoid in every pterosaur. We’ll see if it is universal when more pterosaur specimens of all sorts are presented.


References
Dalla Vecchia FM 2019. Seazzadactylus venieri gen. et sp. nov., a new pterosaur (Diapsida: Pterosauria) from the Upper Triassic (Norian) of northeastern Italy. PeerJ 7:e7363 DOI 10.7717/peerj.7363
Peters D 2007. The origin and radiation of the Pterosauria. In D. Hone ed. Flugsaurier. The Wellnhofer pterosaur meeting, 2007, Munich, Germany. p. 27.
Reynoso V-H 1998. Huehuecuetzpalli mixtecus gen. et sp. nov: a basal squamate (Reptilia) from the Early Cretaceous of Tepexi de Rodríguez, Central México. Philosophical Transactions of the Royal Society, London B 353:477-500.
Wild R 1978. Die Flugsaurier (Reptilia, Pterosauria) aus der Oberen Trias von Cene bei Bergamo, Italien. Bolletino della Societa Paleontologica Italiana 17(2): 176–256.

wiki/Bergamodactylus
wiki/Huehuecuetzpalli
wiki/Homoeosaurus
wiki/Bavarisaurus

Pre-pterosaur skull evolution

Pterosaurs are chiefly known by their post-cranial traits.
Here (Fig. 1) a diagram is presented of pterosaur ancestor skulls in phylogenetic order. Alongside this diagram is a list of general trends documented from the tritosaur lepidosaur, Huehuecuetzpalli (at top), to Macrocnemus to Cosesaurus to Longisquama and culminating with the basal pterosaur, Bergamodactylus (at bottom).

Figure 1. Skulls of pterosaur ancestors from Huehuecuetzpalli through Macrocnemus, Cosesaurus, Longisquama and the pterosaur Bergamodactylus.

Figure 1. Skulls of pterosaur ancestors from Huehuecuetzpalli through Macrocnemus, Cosesaurus, Longisquama and the pterosaur Bergamodactylus.

Huehuecuetzpalli never fits well
into traditional squamate cladograms because it is not a member of the Squamata.

Earlier we looked at the gradual evolution
of the manus in these taxa (Fig. 2). You won’t find evidence like this ‘out there’ in the academic literature where PhDs continue to say, “We still don’t know the ancestors to pterosaurs.” This is rather embarrassing for them, if not now, then someday.

pterosaur wings

Figure 2. Click to enlarge. The origin of the pterosaur wing and whatever became of manual digit 5?

Addendum: originally published online on Facebook yesterday:
For my paleo friends… this is Cosesaurus (Fig. 3), a lepidosaur, not closely related to living lizards, that was able to run bipedally, like some living lizards do by convergence. It had sprawling limbs, but created a narrow gauge trackway matching Early to Middle Triassic Rotodactylus footprints found from Europe to North America. Lateral toe (#5) uniquely bent back to imprint dorsal side down behind the other four regular toes.

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 3. Click to enlarge and animate. 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.

The curved, stem-like, immobile coracoid is an indicator of flapping (birds share this trait), matched to a strap-like scapula (birds share this trait). The interclavicle overlaps the sternum and clavicles to create a pre-sternal complex, as in pterosaurs. A tiny pterosaur-like prepubis is present. So is an anterior projection of the ilium (top pelvic bone) typically found only in bipeds. Two wrist bones migrated to the thumb side of the wrist to create a pteroid and preaxial carpal, otherwise only found in pterosaurs (but similar, by convergence, to the panda’s ‘thumb’). The tail is extremely narrow and stiff.

Extradermal membranes extend from the crest of the skull to the back of the pelvis. Fibers (pre-wings) trail the forelimbs. A membrane trails each hind limb. These and many other traits are shared with pterosaurs, the flying reptiles of the Mesozoic.

Like birds, pterosaur ancestors used their decorative traits (feathers, membranes) for display, including flapping prior to being able to fly. Running bipedally enabled breathing while running (something quadrupedal undulating lizards cannot do). Bipedal locomotion increased stamina and warmed up the metabolism. So secondary sexual traits (decorations and behavior for display) helped create both birds and pterosaurs.

I studied the one-of-a-kind fossil, a hand-sized mold of such exquisite detail that it also preserved a small jellyfish, in Barcelona in the 1990s where it was inappropriately wrapped in a few layers of toilet paper. In 2000 I described Cosesaurus as an ancestor to pterosaurs, and did so by adding it to four previously published phylogenetic analyses.

Unfortunately, that peer-reviewed and academically published paper has been ignored ever since, for reasons I still cannot fathom other than I have no science degree, let alone a PhD. To this day paleontologists repeat the phrase, “We still don’t know where pterosaurs come from.” Frustrating, but I’ve gotten used to it. I guess this posting is just a chance to vent.

For more exquisite Cosesaurus details, click here: http://reptileevolution.com/cosesaurus.htm

Another lepidosaur with a big antorbital fenestra

Quick backstory and summary:
Pterosaurs and their Middle Triassic precursors with a big antorbital fenestra are lepidosaurs (LRT 2020, Peters 2007). Macrocnemus is one of those Middle Triassic precursors, but this one is the only one has a large antorbital fenestra…by convergence.

Skull details on this specimen have been overlooked since 2007.
Macrocnemus fuyuanensis (Li, Zhao and Wang 2007; < 1 m in length; GMPKU P3001, Fig. 1), was the first and only member of this genus not considered conspecific by its authors (actually, no two are alike, see Fig. 3). Earlier we looked at the GMPKU specimen. Today the GMPKU specimen enters the large reptile tree (LRT, 1694+ taxa) today nesting with the T2472 specimen from Europe (Fig. 2).

Figure 1. Macrocnemus fuyuanensis (GMPKU-P-3001) in situ and as traced by the original authors, (middle) flipped with colors applied to bones, and (above) bone colors moved about to form a reconstruction. Darker yellow and darker green are medial views of premaxilla and maxilla. Note the long ascending process of the premaxilla and the palatal elements seen through the various openings all overlooked by those with firsthand access to the fossil. Epipterygoids are lepidosaur synapomorphies not present in protorosaurs.

Figure 1. Macrocnemus fuyuanensis (GMPKU-P-3001) in situ and as traced by the original authors, (middle) flipped with colors applied to bones, and (above) bone colors moved about to form a reconstruction. Darker yellow and darker green are medial views of premaxilla and maxilla. Note the long ascending process of the premaxilla and the palatal elements seen through the various openings all overlooked by those with firsthand access to the fossil. Epipterygoids are lepidosaur synapomorphies not present in protorosaurs.

This referred GMPKU specimen was brought to mind
when Scheyer et al. 2020 discussed in detail the larger holotype M. fuyuarnensis with the skull preserved in ventral view (IVPP V15001, Fig. 4). Scheyer et al. 2020 mistakenly considered it an archosauromorph due to taxon exclusion. Jiang et al. mistakenly considered it a protorosaurian due to taxon exclusion.

All prior workers also overlooked the twin epipterygoids
in the referred specimen (Fig. 1). This is a trait not found outside the Lepidosauria and is lost in several subclades of the Lepidosauria (e.g. Fenestrasauria).

All prior workers overlooked the tiny supratemporals,
which are easy to overlook unless you are looking for them based on phylogenetic bracketing. Taxon exclusion is, once again, the chief problem here. A poor tracing (e.g. Li et al. 2007; Jiang et al. 2011) is the secondary problem.

Figure 2. M. fuyuanensis GMPKU-P-3001 overall. This specimen nests with T2472 in figure 3.

Figure 2. M. fuyuanensis GMPKU-P-3001 overall. This specimen nests with T2472 in figure 3.

The antorbital fenestra
was previously (Li et al. 2007; Jiang et al. 2011) and recently (Scheyer et al. 2020) overlooked because earlier workers considered palatal bones to be rostral bones. That is repaired here (Fig. 1) using DGS methods.

Figure 1. Several Macrocnemus specimens to scale alongside the ancestral taxon in the LRT, Huehuecuetzpalli, and descendant taxa in the LRT, including Cosesaurus and the fenestrasaurs Sharovipteryx, Longisquama and Bergamodactylus. The similarities in transitional taxa should be obvious.

Figure 3. Several Macrocnemus specimens to scale alongside the ancestral taxon in the LRT, Huehuecuetzpalli, and descendant taxa in the LRT, including Cosesaurus and the fenestrasaurs Sharovipteryx, Longisquama and Bergamodactylus. The similarities in transitional taxa should be obvious.

The larger holotype IVPP V15001 specimen
(Fig. 4) preserves the skull upside down (mandible in ventral view). Other elements clearly show the pectoral girdle, pelvic girdle, manus and pes and other elements, more or less in articulation. These are typically scattered in European fossils of Macrocnemus.

Figure 7. The IVPP V15001 specimen of Macrocnemus fuyuanensis in situ. Colors and reconstructions added. Some disagreement here with the pectoral elements.

Figure 4. The IVPP V15001 specimen of Macrocnemus fuyuanensis in situ. Colors and reconstructions added. Some disagreement here with the pectoral elements. Note how the coracoids slide along the interclavicle bound by the sternum reidentified here from the original coracoid. The skull and mandibles are in the center in ventral view.

For those who forget how important the pectoral girdle is
in Macrocnemus and its descendants, others of you might remember the migration of the sternum to the interclavicle, the erosion if the anterior coracoid rim, the elongation of the scapula, the wrapping of the clavicles and the development of the anterior process of the interclavicle that gradually evolves to become the sternal complex in pterosaurs and their flapping precursors, the fenestrasaurs (Fig. 5). This is why it is vitally important to include more taxa in your analyses in order to keep the specimen you are describing in a proper phylogenetic context. All prior workers who studied Macrocnemus lack this context.

Tritosaur pectoral girdles demonstrating the evolution and migration of the sternal elements to produce a sternal complex.

Figure  5. Tritosaur pectoral girdles demonstrating the evolution and migration of the sternal elements to produce a sternal complex.

The Tritosauria (“third lizards”)
is a new squamate clade, now all extinct. The Tritosauria flourished in the Triassic, was reduced to only the Pterosauria during the Jurassic and Cretaceous, and became extinct thereafter. Several members have an antorbital fenestra, most in the lineage of pterosaurs. The GMPKU specimen has an antorbital fenestra convergent with those taxa.

In 2020 pterosaur experts
still have not presented a better hypothesis for the origin of pterosaurs, but prefer to follow their professors who taught them pterosaurs belong with dinosaurs (e.g. Avemetatarsalia, Ornithodira). When will the first one of them break away from promoting this myth?


References
Jiang D-Y, Rieppel O, Fraser NC, Motani R, Hao W-C, Tintori A, Sun Y-L and Sun Z-Y 2011. New information on the protorosaurian reptile Macrocnemus fuyuanensis Li et al., 2007, from the Middle/Upper Triassic of Yunnan, China. Journal of Vertebrate Paleontology 31: 2011-1237, DOI:10.1080/02724634.2011.610853
Li C, Zhao L and Wang L 2007.
A new species of Macrocnemus (Reptilia: Protorosauria) from the Middle Triassic of southwestern China and its palaeogeographical implication. Sci China Ser D: Earth Sci, 50(11): 1601–1605.
Peters D 2007. The origin and radiation of the Pterosauria. In D. Hone ed. Flugsaurier. The Wellnhofer pterosaur meeting, 2007, Munich, Germany. p. 27.
Scheyer TM, Wang W, Li C, Miedema F and Spiekman SNF 2020. Osteological re-description of Macrocnemus fuyuanensis (Archosauromorpha, Tanystropheidae) from the Middle Triassic of China. Vertebrata PalAsiatica. DOI: 10.19615/j.cnki.1000-3118.200525

wiki/Macrocnemus

Late-surviving sharovipterygids in Early Cretaceous Burmese amber

Earlier we looked at a
Oculudentavisa late-surviving cosesaur in Early Cretaceous Burmese amber. I noted it had just a few traits closer to another fenestrasaur, Sharovipteryx (Fig 2).

Figure 1. DGS tracings of two amber entombed Early Cretaceous sharovipterygids.

Figure 1. DGS tracings of two amber entombed Early Cretaceous sharovipterygids.

Today,
two unnumbered, unnamed, undescribed Early Cretaceous fenestrasaurs with even more sharovipterygid traits from the same Burmese amber. These specimens have huge eyes, a larger naris, a small antorbital fenestra, gracile postorbital bones, long cervicals with robust cervical ribs. That gray sickle-shaped area appears to represent the same sort of extendable hyoids seen in Sharovipteryx that extend the neck skin to form canard wing membranes or strakes (Fig. 2). Once again, these poor saps got their head stuck in the resin. The rest of the body was lost to the ages.

For comparison, a complete Sharovipteryx
(Fig. 2) is known from Late Triassic strata, coeval with the first pterosaurs, both derived from Cosesaurus, a lepidosaur tritosaur fenestrsaur.

Figure 3. Sharovipteryx reconstructed. Note the flattened torso.

Figure 3. Sharovipteryx reconstructed. Note the flattened torso.

References
No scale bar, No citation, No museum number, Owner unknown.

Oculudentavis in more incredible detail! (thanks to Li et al. 2020)

Li et al. 2020 bring us
higher resolution scans of the putative tiny toothed ‘bird’ (according to Xing et al. 2020) Oculudentavis (Fig. 1). Following a trend started here a week ago, Li et al. support a generalized lepidosaur interpretation, but then tragically overlook/deny details readily observed in their own data (Fig.1).

FIgure 1. CT scan model from Li et al. 2020, who denied the presence of a quadratojugal and an antorbital fenestra, both of which are present. Colors applied here.

FIgure 1. CT scan model from Li et al. 2020, who denied the presence of a quadratojugal and an antorbital fenestra, both of which are present. Colors applied here. The previously overlooked jugal-lacrimnal suture becomes apparent at this scale and presentation.

Li et al. deny the presence of a clearly visible antorbital fenestra.
They report, “One of the most bizarre characters is the absence of an antorbital fenestra. Xing et al. argued the antorbital fenestra fused with the orbit, but they reported the lacrimal is present at the anterior margin of the orbit. This contradicts the definition of the lacrimal in birds, where the lacrimal is the bone between the orbit and antorbital, fenestra. In addition, a separate antorbital fenestra is a stable character among archosaurs including non-avian dinosaurs and birds, and all the known Cretaceous birds do have a separate antorbital fenestra.”

Contra Li et al.
a standard, ordinary antorbital fenestra is present (Fig. 1 dark arrow) and the lacrimal is between the orbit and antorbital fenestra. This is also the description of the antorbital fenestra and fenestrasaurs, like Cosesaurus (Fig. 2), Sharovipteryx and pterosaurs (Peters 2000).

Li et al. report,
“The ventral margin of the orbit is formed by the jugal.”

Contra Li et al.
the lacrimal is ventral to half the orbit (Fig. 1). The jugal is the other half. The suture becomes visible at the new magnification.

Li et al. report,
“Another unambiguous squamate synapomorphy in Oculudentavis is the loss of the lower temporal bar.” 

Contra Li et al.
the lower temporal bar is created by the quadratojugal, as in Cosesaurus, Sharovipteryx and pterosaurs. In Oculudentavis the fragile and extremely tiny quadratojugal is broken into several pieces. DGS (coloring the bones) enables the identification of those pieces (Fig. 1).

Figure 2. Cosesaurus nasal crest (in yellow).

Figure 2. Cosesaurus with colors applied. Compare to figure 1.

Li et al. conclude,
“Our new morphological discoveries suggest that lepidosaurs should be included in the phylogenetic analysis of Oculudentavis.” 

Contra Li et al.
these are all false ‘discoveries’.

Also note that Li et al. cannot discern
which sort of lepidosaurs should be tested in the next phylogenetic analysis of Oculudentavis. That’s because lepidosaur tritosaur fenestrasaurs, like Cosesaurus (Fig. 2), are not on their radar. That’s because pterosaur referees have worked to suppress the publication of new data on Cosesaurus and kin. And that’s what scientists get for not ‘playing it straight.’


References
Li Z, Wang W, Hu H, Wang M, Y H and Lu J 2020. Is Oculudentavis a bird or even archosaur? bioRxiv (preprint) doi: https://doi.org/10.1101/2020.03.16.993949
Xing L, O’Connor JK,; Schmitz L, Chiappe LM, McKellar RC, Yi Q and Li G 2020. Hummingbird-sized dinosaur from the Cretaceous period of Myanmar. Nature. 579 (7798): 245–249.

wiki/Oculudentavis

 

Was the AMNH Tanytrachelos ‘with child’?

Tanytrachelos ahynis (Olsen 1979, holotype AMNH 7496; holotype Fig. 1) Latest Triassic, 200 mya, was derived from Macrocnemus and was a sister to Langobardisaurus and Tanystropheus. All are tritosaur lepidosaurs in the lineage of the terrestrial ancestors of pterosaurs, the Fenestrasauria… all ultimately derived from an earlier sister to late-surviving Huehuecuetzpalli and Tijubina.

Figure 1. AMNH 7496 holotype of Tanytrachelos with original tracing from Olsen 1979. DGS colors added.

Figure 1. AMNH 7496 holotype of Tanytrachelos with original tracing from Olsen 1979. DGS colors added.

The AMNH specimen
(Fig. 1) preserved in ventral exposure, appears to have two halves of a leathery eggshell and an ‘exploded’ embryo, best described as several dozen tiny bones that should not be there, unless, perhaps this was a gravid adult… or something else, like gastroliths, undigested prey… hard to tell. In any case, some of the pectoral bones also have new identities here.

Figure 5. Hypothetical Tanystropheus embryo compared to Dinocephalosaurus embryo.

Figure 2. Hypothetical Tanystropheus embryo compared to Dinocephalosaurus embryo. These are the sorts and sizes of bones one should look for in any maternal Tanytrachelos.

Figure 1. Tanytrachelos hopping to match Gwyneddichnium tracks (see figure 2).

Figure 3. Tanytrachelos hopping to match Gwyneddichnium tracks (see figure 2).

Distinct from Langobardisaurus,
Tanytrachelos has twelve cervicals, but none were gracile. The posterior cervical ribs had large heads that kept the rods far from each centrum. Heterotopic bones were present. These appear to be elongated chevrons, as in Tanystropheus. Rare hopping prints (Fig. 2) match the size and shape of Tanytrachelos pedes.

langobardisaurus-pectoral-girdle

Figure 4. The sternal complex of several other tritosaurs. Tanytrachelos is closer to Tanystropheus, not quite like any of these related taxa, but all are informative.

The elliptical sternum
of Tanytrachelos was wide, as in Langobardisaurus (Fig. 3), but the clavicle remained gracile, as in Huehuecuetzpalli (Fig. 3). The humerus was slightly bowed. Metacarpal I aligned with the others. Metatarsal III was the longest. Digit III was the longest as in Langobardisaurus tonelloi.


References
Olsen PE 1979. A new aquatic eosuchian from the Newark Supergroup Late Triassic-Early Jurassic) of North Carolina and Virginia. Postilla 176: 1-14.
Smith AC 2011. Description of Tanytrachelos ahynis and its implications for the phylogeny of Protorosauria. PhD dissertation. Virginia Polytechnic Institute and State University.

 

Lepidosaur bipedality and pelvis morphology: Grinham and Norman 2019

Grinham and Norman 2019
brings us a new look at 34 lepidosaur pelves with an emphasis on trends associated with bipedal locomotion. The authors illustrated 11 pelves (Fig. 1, white and yellow areas).
Figure 1. On the left, lepidosaur pelves from Grinham and Norman 2019, reordered phylogenetically here. On the right several tritosaur pelves and prepubes, most of which strongly demonstrate bipedal traits (elongate anterior ilium, increased sacral number). Yellow boxes indicate facultatively bipedal extant lepidosaurs.

Figure 1. On the left, lepidosaur pelves from Grinham and Norman 2019, reordered phylogenetically here. On the right several tritosaur pelves and prepubes, most of which strongly demonstrate bipedal traits (elongate anterior ilium, increased sacral number). Yellow boxes indicate facultatively bipedal extant lepidosaurs.

From the Grinham and Norman abstract:
“Facultative bipedality is regarded as an enigmatic middle ground in the evolution of obligate bipedality and is associated with high mechanical demands in extant lepidosaurs. Traits linked with this phenomenon are largely associated with the caudal end of the animal: hindlimbs and tail. The articulation of the pelvis with both of these structures suggests a morphofunctional role in the use of a facultative locomotor mode. Using a three-dimensional geometric morphometric approach, we examine the pelvic osteology and associated functional implications for 34 species of extant lepidosaur. Anatomical trends associated with the use of a bipedal locomotor mode and substrate preferences are correlated and functionally interpreted based on musculoskeletal descriptions. Changes in pelvic osteology associated with a facultatively bipedal locomotor mode are similar to those observed in species preferring arboreal substrates, indicating shared functionality between these ecologies.”
Unfortunately, Grinham and Norman omitted
tritosaur lepidosaurs from their study. In the Triassic many of them became bipeds and among these, pterosaurs achieved bipedalism supported with four, five and more sacral vertebrae between horizontally elongate ilia, convergent with dinosaurs. The addition of the prepubis virtually extended the anchorage for the puboischial muscles. After achieving flight, beach-combing pterosaurs reverted to a quadrupedal configuration with finger 3 pointing posteriorly. Giant Korean bipedal pterosaur tracks are best matched to large dsungaripterid/tapejarid clade taxa.
Unfortunately, Grinham and Norman reported,
“A recently published molecular-based time-calibrated phylogeny for Squamata was pared down to match the species in our dataset.” Their genomic cladogram bears little to no resemblance to the large reptile tree (LRT, 1635+ taxa), which tests traits, not genes. Once again, genes produce false positives. 
The authors’ principal component analysis of the pelvis failed 
to isolate bipedal lepidosaurs from the rest. Grinham and Norman reported, “The shape of the pelvis in facultatively bipedal extant lepidosaurs falls within the overall morphospace of lepidosaurs generally.” This is also visible in their illustrated pelves (Fig. 1). They also reported, However, it is generally found in a very concentrated area of that morphospace.” And Conclusions can be drawn regarding pelvic morphology and substrate use, although not with the same clarity as for locomotor mode.”
Grinham and Norman 2019 conclude,
“we have used 3D landmark-based geometric morphometrics to demonstrate that the overall morphospace for the lepidosaur pelvis is broad and wide-ranging. Within this overall morphospace, a small region is occupied by facultative bipeds. The vast majority of this smaller morphospace overlaps that occupied by species that show a preference for arboreal habitats. Pelvic morphological adaptations relevant for living in an arboreal environment are similar to those necessary to facilitate facultative bipedality.”
That’s interesting with regard to
the arboreal abilities of volant basal bipedal pterosaurs and their ancestors. Maybe next time Grinham and Norman will expand their study to include tritosaur lepidosaurs.

References
Grinham LR and Norman DB 2019. 
The pelvis as an anatomical indicator for facultative bipedality and substrate use in lepidosaurs. Biological Journal of the Linnean Society, blz190 (advance online publication) doi: https://doi.org/10.1093/biolinnean/blz190
https://academic.oup.com/biolinnean/advance-article-abstract/doi/10.1093/biolinnean/blz190/5687877Â
Peters D 2000b. A Redescription of Four Prolacertiform Genera and Implications for Pterosaur Phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia 106 (3): 293–336.
Snyder RC 1954. The anatomy and function of the pelvic girdle and hind limb in lizard locomotion. American Journal of Anatomy 95:1-46.

Pterosaur prebubis

 

New tanystropheid paper promotes archosauromorph myth

Colleagues. Stop promoting this myth.
Formoso  et al. 2019 report that Tanystropheus (Fig. 1) is an archosauromorph. Dr. Sterling Nesbitt, known for his widely cited, but poorly populated and scored  2011 cladogram, is a co-author. Their nesting of Tanystropheus as an archosauromorph is only possible by way of taxon exclusion and the omission of pertinent published works. Peters 2007 and the large reptile tree (LRT, 1611+ taxa, subset Fig. 2) firmly and unequivocally nest tanystropheids within the Tritosauria, within the Lepidosauria, within the Lepidosauriformes and within the Lepidosauromorpha.

Tanystropheus underwater among tall crinoids and small squids.

Figure 1. 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.

Formoso et al. report,
“Tanystropheids are a unique group of archosauromorph reptiles, which likely appeared in the Late Permian (based on inferred ghost lineages) and diversified within five million years after the end-Permian extinction.”

By contrast
the LRT nest tanystropheids as sister taxa to pterosaurs, some of which had similar elongated cervicals, all derived from basal tritosaurs like Huehuecuetzpalli, Bavarisaurus macrodactylus and Tjubina. The protorosaur, Ozmik, had elongate cervicals. None of these are mentioned in the text. Strangely there is also no citation for Fuyuansaurus and Pectodens, the basalmost taxa in the Tanystropheus clade in the LRT (subset Fig. 2). They are all Middle Triassic taxa, as are all the macrocnemids. The only known Late Permian taxa in the LRT lineage of Tanystropheus are the basal arboreal lepidosauriformes, Saurosternon and Palaegama.

So where does this
“likely appeared in the Late Permian” supposition come from?

The authors uncritically cite Sennikov 2011
who mistakenly placed his tanystropheid, Augustaburiania vatagini, in the Early Triassic, perhaps based on Sennikov’s earlier similar mistake with regard to the coeval sauropterygian Tanaisosaurus kalandadzei. No other sister taxa for either taxon predate the Middle Triassic. Sennikov describes, “The Triassic beds of the Lipovskaya Formation are eroded, overlie Carboniferous marine limestones, and are covered by Middle Jurassic continental sands and clays.” Based on phylogenetic bracketing, the Lipovskaya is a Middle Triassic formation.

Formosa et al. also cite, “Early Triassic tanystropheid elements from the Sanga do Cabral Formation of Brazil (Olsen, 1979; Casey et al., 2007; Sues and Fraser, 2010; Sues and Olsen, 2015; Pritchard et al., 2015; De Oliveira et al., 2018; Lessner et al., 2018).”

  1. Olsen 1979 refers to Tanytrachelos and the Newark Supergroup is Late Triassic-Early Jurassic.
  2. Casey et al. 2007 also refers to TanytrachelosCow Branch Formation of the Dan River Basin, part of the Newark Supergroup… Late Triassic (Carnian) age.
  3. Sues and Fraser, 2010 is a book on Triassic life.
  4. Sues and Olsen, 2015 does not appear on their list of references/citations
  5. Pritchard et al., 2015 discuss “Late Triassic tanystropheids…”
  6. De Oliveira et al., 2018 discuss,”Tanystropheid archosauromorphs in the Lower Triassic of Gondwana, Sanga do Cabral Formation of Brazil (see below).
  7. Lessner et al., 2018) report on “New insights into Late Triassic dinosauromorph-bearing assemblages”
  8. Formosa et al. assign their finds to the Middle Triassic (Anisian; 247-242 Ma).

De Oliveira et al. 2018 report,
“The fossil assemblage of the Sanga do Cabral Formation so far includes procolophonids, temnospondyls, and archosauromorphs. Vertebrate fossils are often found isolated and disarticulated. This preservation mode suggests extensive exposure and post-mortem transport of bones during the biostratinomic phase, and subsequent reworking after diagenesis.”

A Middle to Late Triassic time window for tanystropheids
is best supported here, along with a call for better editing among the several academic authors.

So, some phylogenetic and chronological problems surfaced
in Formosa et al. 2019. Reason: all scientists accept without testing, sometimes, because it’s easier. It remains important not to perpetuate myths in science, starting here and now.

Figure 5. Subset of the LRT focusing on the Tritosauria. Note the separation of one specimen attributed to Macrocnemus.

Figure 2. Subset of the LRT focusing on the Tritosauria. Note the separation of one specimen attributed to Macrocnemus.

Interesting phylogenetic note:
The clade Tanystropheidae is defined as the most recent common ancestor of MacrocnemusTanystropheus, Langobardisaurus Renesto, 1994, and all of its descendants (Dilkes 1998). In the LRT, that definition includes pterosaurs and their outgroups (Fig. 2).

Tanystropheus and kin going back to Huehuecuetzpalli.

Figure 3. Tanystropheus and kin going back to Huehuecuetzpalli. Note the scale change from the white zone to the yellow zone with duplicated taxa.

Size
Formosa et al. report,“The Moenkopi tanystropheid cervical vertebrae belong to a considerably smaller tanystropheid than the largest Tanystropheus, but we determined that its body length was approximately three times larger than Tanytrachelos ahynis known primarily from the eastern United States.” Earlier Pritchard et al. 2015 described relatively giant Tanytrachelos specimens from the same formation. Those are not the same specimens described by Formosa et al.


References
Formosa KK, Nesbitt SJ, Pritchard AC, Stocker MR and Parker WG 2019. A long-necked tanystropheid from the Middle Triassic Moenkopi Fromation (Anisian) provides insights into the ecology and biogeography of tansytropheids. Palaeontologia Electronca 22.3.73 online
Peters D 2007. The origin and radiation of the Pterosauria. In D. Hone ed. Flugsaurier. The Wellnhofer pterosaur meeting, 2007, Munich, Germany. p. 27.
Pritchard AC, Turner AH, Nesbitt SJ, Irims RB & Smith ND 2015. Late Triassic tanystropheids (Reptilia, Archosauromorpha) from northern New Mexico (Petrified Forest Member, Chinle Formation) and the biogeography, functional morphology, and evolution of Tanystropheidae. Journal of Vertebrate Paleontology 35(2):e911186, 20pp
Sennikov AG 2001. Discovery of a Primitive Sauropterygian from the Lower Triassic of the Donskaya Luka (Don Basin) and the Range of Triassic Marine Reptiles in Russia. Paleontological Journal 35(3):301–309.
Sennikov AG 2011. New Tanystropheids (Reptilia: Archosauromorpha) from the Triassic of Europe. Paleontological Journal 45(1): 90–104.

https://pterosaurheresies.wordpress.com/2015/09/26/relatively-giant-tanytrachelos-specimens/

The first Langobardisaurus: MCSNB 2883

The day before yesterday
we looked at the latest (fourth) specimen attributed to the genus Langobardisaurus (Renesto 1994, Late Triassic). Today let’s look at the first specimen. This is really my first serious look at it because the second and third specimens were so much easier to study, both with good skulls.

The holotype of Langobardisaurus
(Renesto 1994, MCSNB 2883) has never (to my knowledge) been reconstructed, as it is here (Fig. 1), and not with to scale comparisons to the other three specimens. Saller et al. 2013 considered all four to be conspecific. However, as I found out, and as in so many putative pterosaur genera and Archaeopteryx genera, no two are alike.

Figure 1. Four Langobardisaurus specimens compared to scale. Contra Saller et al. 2013, these four specimens do not appear to be conspecific.

Figure 1. Four Langobardisaurus specimens compared to scale. Contra Saller et al. 2013, these four specimens do not appear to be conspecific.

Larger than the others (if the scale bars are correct),
the holotype of Langobardisaurus appears to have a smaller skull, smaller fingers and longer hind limbs. Distinct from two of the specimens, the tail remains long and robust. Powerful caudofemoral muscles were attached the elongate and numerous caudal ribs (fused transverse processes). The gastralia were more numerous with less space between sets. Such gastralia help hold up the anterior skeleton when standing bipedally. This specimen (MCSNB 2883) appears to be, by convergence, like Sharovipteryx, an obligate biped.

Figure 2. Langobardisaurus holotype in situ MCSNB 2883.

Figure 2. Langobardisaurus holotype in situ MCSNB 2883. Inserts show pectoral girdle elements and pes (x2).

Almost a worst case scenario for a roadkill fossil
the pectoral + skull region of MCSNB 2883 (Fig. 3) provides an excellent opportunity to try out the Digital Graphic Segregation (DGS) method. In the original photo you can see what a mess it is and how Renesto has labeled some of the bones and teeth, but ignores others and never outlines any of the bones. Colors just make things easier to understand in cases like this and it ensures that you are studying every millimeter of this fossil. Even tiny bone corners that peek out from beneath the rubble can be color coded. The reconstruction (Fig. 1) confirms or refutes your identifications as they fit or do not fit the assembled puzzle of bones without resorting to the danger of freehand illustration.

Figure 3. The pectoral region of Langobardisaurus (MCSNB 2883) with DGS color overlays. Compare to Figure 4 for identification of pectoral elements. Anterior skull elements are also present here.

Figure 3. The pectoral region of Langobardisaurus (MCSNB 2883) with DGS color overlays. Compare to Figure 4 for identification of pectoral elements. Anterior skull elements are also present here. Premaxillae and sternum are both yellow. Scapulae are blue. Coracoids are violet. Clavicles are green. Interclavicle is tan. Ribs are red. The tiny metacarpals are still attached to the end of the ulna and radius (amber and green).

The coincidence of the interclavicle, clavicle and sternum
in Langonbardisaurus (Fig. 4) and other fenestrasaurs like Cosesaurus and Longisquama is the precursor structure to the pterosaur sternal complex, seen only in this clade within the entire Tetrapoda.

Figure 5. Langobardisaurus (MCSNB 2883) pectoral girdle in left lateral and ventral views.

Figure 4. Langobardisaurus (MCSNB 2883) pectoral girdle in left lateral and ventral views.

References
Muscio G 1997. Preliminary note on a specimen of Prolacertiformes (Reptilia) from the Norian (Late Triassic) of Preone (Udine, north-eastern Italy). Gortania – Atti del Museo Friulano di Storia Naturale 18:33-40
Renesto S 1994. A new prolacertiform reptile from the Late Triassic of Northern Italy. Rivista di Paleontologia e Stratigrafia 100(2): 285-306.
Renesto S and Dalla Vecchia FM 2000. The unusual dentition and feeding habits of the Prolacertiform reptile Langobardisaurus (Late Triassic, Northern Italy). Journal of Vertebrate Paleontology 20: 3. 622-627.
Renesto S, Dalla Vecchia FM and Peters D 2002. Morphological evidence for bipedalism in the Late Triassic Prolacertiform reptile Langobardisaurus. Senckembergiana Lethaea 82(1): 95-106.
Saller F, Renesto S, Dalla Vecchia FM 2013. First record of Langobardisaurus (Diapsida, Protorosauria) from the Norian (Late Triassic) of Austria, and a revision of the genus. Neues Jahrbuch für Geologie und Paläontologie. 268 (1): 89–95. doi:10.1127/0077-7749/2013/0319
Wild R 1980. Tanystropheus (Reptilia: Squamata) and its importance for stratigraphy. Mémoires de la Société Géologique de France, N.S. 139:201–206.

uninisubria/Langobardisaurus
wiki/Langobardisaurus