Hamipterus egg accumulation: Wang et al. 2017

Earlier
here and here we looked at the 3-D eggs of Hamipterus, a basal ornithocheirid from Early Cretaceous China. The eggs are scattered in and amongst a wide size/age range of disarticulated, but 3-D fossils. So, according to the authors, the eggs were buried, then bones and eggs were transported by storms, as if bulldozed. No embryos were reported from those eggs. No explanation why the pterosaurs did not fly away in the face of the storm, nor why more sediment wasn’t packed on the buried eggs during the storm.

Today
comes news from this expanding treasure trove site with embryo bones at several stages of development in 16 eggs out of hundreds! That’s good news because full-term embryos (= hatchlings) are identical to parents and eggs keep all the bones from an individual in a neat little package so we can finally put together what Hamipterus looked like.

But that’s not the picture the authors paint.
They said, “some bones lack extensive ossification in potentially late-term embryos, suggesting that hatchlings might have been flightless and less precocious than previously assumed.” Point-by-point:

  1. No nests were found.
  2. 215+ eggs were found
  3. Eggs appeared in moderate size variation
  4. The large number of accumulated eggs (Fig. 1) indicates they were laid by different females
  5. Some were subjected to differential water uptake during transport
  6. Internal content(?) observed in 42 eggs, 16 had embryos
  7. Bones not concentrated on the bottom half of the egg, as in dinosaurs
  8. No embryo is complete. One to several bones only in each of the 16 eggs.
  9. No teeth found in embryos.
  10. The most complete embryo had a lower jaw of 17mm. That’s 4% the size of the largest adult when other full-term pterosaur embryos are 12.5% (1/8) at hatching. So these were not full-term embryos ready to hatch.
  11. In a 2.2m section, eight layers with pterosaur bones have been identified, four of which show egg concentrations in a vertical distance of 1.4 m.

The authors note and conclude:
“This suggests that the hind limbs have developed more rapidly compared to the forelimbs and might have been functional right after the animal hatched. Thus, newborns were likely to move around but were not able to fly, leading to the hypothesis that Hamipterus might have been less precocious than advocated for flying reptiles in general (6) and probably needed some parental care.”

No. Think again.
Pterosaur mothers carried their eggs inside their bodies until just before hatching. That gives their babies warmth and protection until they are ready to hatch. They could do this because they are lepidosaurs, as phylogenetic analysis AND egg shell thickness and pliability tells us.

Figure 1. From Wang et al. 2017, a pterosaur egg and bone accumulation. Eggs float. So do hollow pterosaur bones.

Figure 1. From Wang et al. 2017, a pterosaur egg and bone accumulation. Eggs float. So do hollow pterosaur bones.

Sedimentology report:
“This sedimentological data, associated with the exceptional quantity of eggs and bones, indicate that events of high energy such as storms have passed over a nesting site, causing the eggs to be moved inside the lake where they floated for a short period of time, becoming concentrated and eventually buried along with disarticulated skeletons.”

Bottom line and biggest problem:
The authors assume the eggs were laid. That’s because they think pterosaurs are archosaurs. Birds and crocs are archosaurs and they lay their eggs at an early stage of fertilization. Lepidosaurs wait to lay their eggs, sometimes until the moment before hatching.

Alternative hypothesis:

  1. Mass death of several year-classes of pterosaurs on beach due to lake burping deadly carbon dioxide. That stops the parents from flying away.
  2. Dessication and insect decomposition reveals eggs inside of female skeletons. This takes just a few days to a week and allows skeletons to easily separate into individual bones (Fig. 1)
  3. Later rising waters (storms optional, melting snow pack will do), overwhelms beached skeletons and exposed eggs. Even a few extra inches of water would be enough for this.
  4. Eggs float. So do pterosaur bones
  5. Wind/ripples push eggs and bones together back against beach bank corner where they accumulate. (This happened several times over dozens to hundreds of years, but not annually.)
  6. Water recedes leaving eggs en masse along with settling disarticulated individual bones of parents and kin
  7. Burial process is later completed with airborne or waterborne sediments overwhelming the bones and eggs in situ.
  8. To point #3 above: moderate egg size variation, we also see this in the chicken eggs we get at our local grocery, but pterosaurs kept growing throughout their lives and larger ones would tend to lay bigger eggs, though this has not been conclusively demonstrated, it seems broadly logical.

Evidently
the lake burping did not always coincide with the pterosaurs flocking together. But it happened four times to a portion of the flock, perhaps over hundreds of years, and evidently at ‘the back of the room where bad things happen’.

References
Wang X and 16 co-authors 2017. Egg accumulation with 3D embryos provides insight into the life history of a pterosaur. Science 358:1197–1201.

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Would you like to read a rejection notice, or two?

In the past week
I submitted a comment to Royal Society Proceeedings B on Foth and Joyce 2017. In it I suggested that the origin of turtles was diphyletic and that would affect the placement of the basalmost turtle in the work of Foth and Joyce.

Referee number 1 wrote:
“This paper is unsuitable for Proceedings B (or any scientific journal) and should be rejected. It is ostensibly a response to a recent paper by Foth & Joyce on the disparity of the turtle skull over time, but in reality it doesn’t address this study at all, but is a back-handed attempt by the author to publish an iconoclastic phylogenetic analysis based on an inadequate dataset riddled with errors and methodological flaws. Sorry, there is no way to be kind about this manuscript.”

Referee number 2 (Walter Joyce, one of the original authors) wrote:
“the attached manuscript by David Peters is a response to an article I published earlier this year with Christian Foth in Proceedings B regarding the evolution of cranial disparity in turtles (Foth and Joyce 2017). Although I welcome any scientific debate regarding this paper, I would like to suggest outright rejecting this contribution for one single reason: It is an open trade secret that David Peters has been developing an enormous phylogeny of reptiles that produces highly outlandish results. One such outlandish result is the polyphyletic origin of turtles. This undertaking has been submitted to many journals over the years and has been rejected every time, as basic tenants of sound cladistic analysis are not followed therein, mostly an adherence to the use of character observations that can be reproduced by people who are not David Peters. I am certain that countless scientists invested countless hours in providing sound arguments why this tree should be rejected and I will therefore save myself the work here. If anything, this phylogeny should receive full peer review in a standalone publication, and not be slipped into the sphere of published scientific literature as part of a not-quite appropriate criticism of Foth and Joyce (2017).”

And here is my reply to the editors:
“Critical thinking is a requirement in science and I’ve had a few hours now to critically think about the replies I received from the two referees. I hope these comments will help you in future endeavors.

1. You already know that referees should be unbiased when they approach a manuscript. Asking Dr. Joyce to be a referee runs counter to that ideal. After all, I was commenting on his paper. His comments should have been requested only after two unbiased referees had ok’d the manuscript for publication.

2. Some referees like to accept manuscripts knowing ahead of time they will reject them. Is there any method you use to prevent this?

3. Whenever I review a manuscript I review some of the details within the manuscript, pointing out errors, if any, congratulating insights, if any. This was not done by either referee. There is no indication that either referee actually read the manuscript, let alone tested the hypotheses that resulted with the matrix provided.

4. The paper was about taxon exclusion. Foth and Joyce excluded taxa pertinent to the origin of turtles, which affected their basalmost taxon and the rest of their phylogram. That point was ignored by both referees who described ‘an inadequate data set’ (did they actually see the dataset, or go by rumors?). No specifics were put forth. No testing of the analysis was described. That’s what I do in such cases. I run the matrix looking for mismatches. Anyone who has the same taxon list, no matter what their character list, will come to the same results as I did, unless they omit certain pertinent taxa, as Foth and Joyce did.

5. Joyce wrote: “It is an open trade secret that David Peters has been developing an enormous phylogeny of reptiles that produces highly outlandish results.”

To that point, many results of my studies follow traditional topologies: birds nest with birds, turtles with turtles, etc. When topologies shift it is virtually always because the large size of the cladogram allows taxa that have not been tested together to be tested together. That the results upset untested traditions and paradigms are THE reason why this work should be published. The origin of turtles could have been known for the last fifty years. I just included taxa that were previously excluded.

Joyce may be upset because i pointed out this oversight, after all the hours he put into his project. That’s never welcome news, especially when that correction comes from someone without a PhD. It is potentially embarassing. Nevertheless, even if the hypotheses comes from an obscure patent clerk, this is how we build our science. The present facts should be central to the case, not any disparaging rumors about the scientist.

The data presented has to be good. Otherwise there is no way for the cladogram to have high Bootstrap scores throughout. The software is unbiased with regard to output. Unfortunately, pride, shame and other emotions are involved here when it comes to the referees. Some don’t like change.

Thank you for reading this. I don’t ask for any revision to the status of my manuscript, only that you review your policies so bias does not influence the next few incoming manuscripts.

Best regards,”

Dimorphodon revisited

The odd pterosaur, Dimorphodon
was one of the first taxa included in the large reptile tree (LRT, 1132 taxa). Here I revise earlier errors on the BMNH 41212 specimen (Fig. 1), including adding a short tail discovered a few days ago and also adding more dorsal vertebrae.

Figure 1. The three Dimorphodon specimens traced from the fossils.

Figure 1. The three Dimorphodon specimens traced from the fossils.

Here is the in situ fossil with bones colorized (Fig. 2).

Figure 2. The BMNH 4121 fossil of Dimorphodon here colorized using DGS.

Figure 2. The BMNH 4121 fossil of Dimorphodon here colorized using DGS. Colors match the reconstruction, except for the skull.

Earlier the skull was reconstructed. Here it is again (Fig. 3). This was done to show the mandible did not have a fenestra, only a shifted surangular.

The skull of Dimorphodon macronyx.

Figure 3. The skull of Dimorphodon macronyx. Above: in situ. Middle: Restored. Below: Palatal view. Not settled on the depth of the mandible. The long replaceable teeth suggest a deeper mandible is more appropriate.

References
Buckland W 1829. Proceedings of the Geological Society London, 1: 127
Owen R 1859. On a new genus (Dimorphodon) of pterodactyle, with remarks on the geological distribution of flying reptiles.” Rep. Br. Ass. Advmnt Sci., 28 (1858): 97–103.
Nesbitt SJ and Hone DWE 2010. An external mandibular fenestra and other archosauriform character states in basal pterosaurs. Palaeodiversity 3: 225–233
Padian K 1983. Osteology and functional morphology of Dimorphodon macronyx (Buckland) (Pterosauria: Rhamphorhynchoidea) based on new material in the Yale Peabody Museum, Postilla, 189: 1-44.
Sangster S 2001. Anatomy, functional morphology and systematics of Dimorphodon. Strata 11: 87-88

wiki/Dimorphodon

Basal reptile hands: Casineria and Diplovertebron

I reexamined two fossils
via photos and found ways to improve the interpretation of both of them, Casineria (Fig. 1) and Diplovertebron (Fig. 2).

Figure 1. Manus of Casineria, a basal archosauromorph reptile. The carpals are unosssified, but left vague impressions in the matrix. Other bones overlapped the carpals and are removed here.

Figure 1. Manus of Casineria, a basal archosauromorph reptile. The carpals are unosssified, but left vague impressions in the matrix. Other bones overlapped the carpals and are removed here. PIls added.

Diplovertebron punctatum (Fritsch 1879, Waton 1926; DMSW B.65, UMZC T.1222a; Moscovian, Westphalian, Late Carboniferous, 300 mya) aka:  Gephyrostegus watsoni Brough and Brough 1967) and Gephyrostegus bohemicus (Carroll 1970; Klembara et al. 2014) after several name changes perhaps this specimen should revert back to its original name as it nests a few nodes away from Gephyrostegus.

Derived from a sister to EldeceeonDiplovertebron was basal to the larger Solenodonsaurusand the smaller BrouffiaCasineria and WestlothianaDiplovertebron was a contemporary of Gephyrostegus bohemicus, Upper Carboniferous (~310 mya), so it, too, was a late survivor.

Overall smaller and distinct from Eldeceeon, the skull of Diplovertebron had a shorter rostrum, larger orbit and greater quadrate lean. The dorsal vertebrae formed a hump and had elongate spines. The hind limbs were much longer than the forelimbs. The tail is incomplete, but appears to have been short and deep. Seven sphere shapes were preserved alongside this specimen. They may be the most primitive amniote eggs known.

Figure 2. Diplovertebron manus in situ and reconstructed with PILs added. What appear to be displaced carpals may be something else entirely. The carpals may have been unossified, as in Casineria.

Figure 2. Diplovertebron manus in situ and reconstructed with PILs added. What appear to be displaced carpals may be something else entirely. The carpals may have been unossified, as in Casineria. See how DGS makes reconstruction less chaotic?

Casineria kiddi (Paton, Smithson & Clack 1999) Visean, Mississippean, Carboniferous, ~335 mya was a small basal archosauromorph. the oldest but not the most primitive. It was derived from a sister to Diplovertebron and SolenodonsaurusWestlothiana was a sister taxon.

Overall smaller than and distinct from Gephyrostegus, the skull of Casineria had no otic notch. See Brouffia for more possible skull details. The cervicals of Casineria were increased in number but decreased in size. The presacral vertebral count had increased to over 30. Ribs discontinued after #22. Apparently two vertebrae formed the sacrum and were connected to the pelvis. The pectoral girdle was composed of unfused elements. The humerus had a small hourglass shape. The manus was enlarged. The ilium had no anterior dorsal process. The femur was more gracile. The pes was reduced, more nearly the size of the manus.

References
Brough MC and Brough J 1967. The Genus Gephyrostegus. Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences 252 (776): 147–165.
Carroll RL 1970. The Ancestry of Reptiles. Philosophical Transactions of the Royal Society London B 257:267–308. online pdf
Fritsch A 1879. Fauna der Gaskohle und der Kalksteine der Permformation “B¨ ohmens. Band 1, Heft 1. Selbstverlag, Prague: 1–92.
Klembara J, Clack J, Milner AR and Ruta M 2014. Cranial anatomy, ontogeny, and relationships of the Late Carboniferous tetrapod Gephyrostegus bohemicus Jaekel, 1902. Journal of Vertebrate Paleontology 34:774–792.
Paton RL Smithson TR and Clack JA 1999. An amniote-like skeleton from the Early Carboniferous of Scotland. Nature 398: 508-513.
Watson DMS 1926. VI. Croonian lecture. The evolution and origin of the Amphibia. Proceedings of the Zoological Society, London 214:189–257.

wiki/Gephyrostegus
wiki/Diplovertebron
wiki/Casineria

 

Pandion, the osprey, joins the LRT

And the osprey,
Pandion haliaetus (Linneaus 1758) joins the large reptile tree (LRT, 1124 taxa) at the base of (owls + swifts) + (Old World vultures + falcons). The secretary bird, Sagittarius, and the terror birds are proximal outgroups.

Figure 1. Pandion, the osprey, nests at the base of the birds of prey, sans the secretary bird and seriema.

Figure 1. Pandion, the osprey, nests at the base of the birds of prey, sans the secretary bird and seriema.

So the osprey is a basal
short-legged, arboreal birds-of-prey.

Wikipedia reports,
“The osprey differs in several respects from other diurnal birds of prey. Its toes are of equal length, its tarsi are reticulate, and its talons are rounded, rather than grooved. The osprey and owls are the only raptors whose outer toe is reversible, allowing them to grasp their prey with two toes in front and two behind. It has always presented something of a riddle to taxonomists, but here it is treated as the sole living member of the family Pandionidae, and the family listed in its traditional place as part of the order Falconiformes.”

References
Linnaeus C 1758. Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata.

wiki/Osprey

 

Were early pterosaurs inept terrestrial locomotors?

Witton 2015 asked:
“Were early pterosaurs inept terrestrial locomotors?” Sorry, this online paper escaped my notice until now. It’s two years old.

The answer is
an unqualified “YES” when Witton turns perfectly good bipeds (supported by morphology, outgroups (Fig. 2), ichnites and omitted citations), into stumbling quadrupeds encumbered by imaginary wing membranes (Fig. 3) that connect the ankles and lateral pedal digits to the wing tips and binds the legs together with a single uropatagium. The Unwin influence is strong in those English youngsters. He also rotates the humerus in a shoulder joint that does not permit rotation (Fig. 1), which would be very bad for a flapping reptile, bird or bat.

Figure 1. Tracings from bones (on left) compared to Witton's freehand quads. Comments in red.

Figure 1. Tracings from bones (on left) compared to Witton’s freehand quads. Comments in red.

From the Witton abstract:
“Pterodactyloid pterosaurs are widely interpreted as terrestrially competent, erect-limbed quadrupeds, but the terrestrial capabilities of non-pterodactyloids are largely thought to have been poor.”

This may be true when you construct pterosaurs that don’t match footprints and you have no idea where ‘early pterosaurs’ came from, even though that has been known for 17 years. Obligate bipeds (Longisquama and Sharovipteryx) are outgroups. Basalmost pterosaur, Bergamodactylus (Fig. 2) , has longer hind limbs and shorter forelimbs (Fig. 2) than other pterosaurs, retaining these plesiomorphic traits.

Figure 2. Updated reconstruction of Bergamodactylus to scale with an outgroup, Cosesaurus.

Figure 2. Updated reconstruction of Bergamodactylus to scale with an outgroup, Cosesaurus. Does this look like a quadruped to anyone? All derived pterosaurs have relatively shorter legs. Outgroups, whether the invalid Scleromochlus, or the valid Sharovipteryx, have long legs like these. Uropatagia are not preserved, but they are on a related taxa one node away, Sharovipteryx. Note the tail is NOT incorporated.

Witton’s abstract continues
“This is commonly justified by the absence of a non-pterodactyloid footprint record,”

(False, see Peters 2011)

“suggestions that the expansive uropatagia common to early pterosaurs”

(False, misinterpretation of Sordes)

“would restrict hindlimb motion in walking or running, and the presence of sprawling forelimbs in some species.”

(sprawling at the top, narrow gauge on the substrate (Fig. 3).

“Here, these arguments are re-visited and mostly found problematic. Further indications of terrestrial habits include antungual sesamoids, which occur in the manus and pes anatomy of many early pterosaur species, and only occur elsewhere in terrestrial reptiles, possibly developing through frequent interactions of large claws with firm substrates.”

Or possibly by grasping branches and tree trunks, but even that possibility is not considered or argued against by Witton.

Getting back to the uropatagium found in bats…
primitive bats extend a membrane from both legs back to the tail. Only in the most derived bats, like Desmodus (Fig. 3), is the tail a vestige to absent. The resulting uropatagium without the tail extends between the legs – while completely avoiding the toes. Thus the pterosaur/bat analog, is also bogus. Final point: basal bats don’t walk or run on their hind limbs. They hang. Only in bats like the vampire do some bats reacquire the ability to actively hop around on horizontal surfaces, like cow buttocks and grassy knolls.

Witton carefully avoids
any mention of papers in which bipedal pterosaur trackways are described (Peters 2011). He fully supports the uropatagium hypothesis proposed by Sharov 1971 and further supported by Unwin and Bakhurina 1994 (disputed by Peters 2002 and here). That uropatagium, found in no other specimens of Sordes or any other pterosaur, is really a displaced wing membrane (Figs. 3–5) along with a displaced radius and ulna as shown here. Note: a few days ago Witton’s latest illustration used pedal digit 5 to frame both the uropatagium and the brachiopatagium. No one else does this. No argument or explanation is given.

Figure 6. Above, from Witton 2017 focusing on the pterosaur uropatagium. Note: even though fanciful, it does not incorporate the tail, but goes from leg to leg, UNLIKE Desmodus the bat, which incorporates what little tail is left.

Figure 3. Above, from Witton 2017 focusing on the pterosaur uropatagium. Note: even though fanciful, it does not incorporate the tail, but goes from leg to leg, UNLIKE Desmodus the bat, which incorporates what little tail is left. Besides, their is NO homology here. Witton is trying to support a bad interpretation with a bad analogy. Not a good idea to support an analogy with invalid drawings. Witton gives no support through testing to the uropatagium controversy, but accepts it with blinders on.

Witton carefully avoids
any mention of other candidate pterosaur outgroups, like fenestrasaurs (Fig. 2), and the assistance they can offer to the questions posed, but supports the basal bipedal crocodylomorph, Scleromochlus, as a potential outgroup. Ironic, isn’t it?

My first question would be, which outgroup taxon has anything resembling a leg-spanning uropatagium?Certainly not phytosaurs. Nor any archosaur. Sharovipteryx has separate uropatagia, but in Witton’s world view those are not the same, nor are they to be mentioned, because that would involve citing some academic paper from Peters, which would be antithetical to Witton’s premise. In good science, all counterarguments are considered, attacked or supported.

The myth of the pterosaur uropatagium

Figure 4. The Sordes uropatagium is actually displaced wing material carried between the ankles by the displaced radius and ulna.

Witton supports
the invalid shrinkage hypothesis of Elgin, Hone and Frey (2011) to explain away narrow-chord wing membranes preserved in the fossil record…which would be ALL of them

The hind limbs and soft tissues of Sordes.

Figure 5. The hind limbs and soft tissues of Sordes. Above, color-coded areas. Below the insitu fossil. Note how insubstantial the illusory uropataigum is compared to the drawing that solidifies the area. Tsk.Tsk.

Witton reports,
“Trackways made by running pterodactyloids indirectly demonstrate how elastic their proximal membranes must have been, allowing track makers to take strides of considerable magnitude (Mazin et al., 2003) despite membranes stretching from the distal hindlimb to their hands (Elgin, Hone & Frey, 2011).” The other explanation is that the wings and hind limbs were always decoupled (as documented in all known fossils). Pterosaurs do not have a membrane extending to the ankles. Witton proposes a bounding gait for pterosaurs, even though no pterosaur tracks document this.

Figure 7. A plesiomorphic bat with the tail incorporated in the uropatagium. This bat, Myotis, cannot walk very well. Desmodus, highly derived, has required the ability to walk, but at the expense of its tail and a vestige uropatagium.

Figure 6. A plesiomorphic bat with the tail incorporated in the uropatagium. This bat, Myotis, cannot walk very well. Desmodus, highly derived, has required the ability to walk, but at the expense of its tail leaving a vestige uropatagium. Everything must be put into a phylogenetic context, even in analogies.

Thankfully Witton supports
“Assessments of pterosaur hindlimb muscle mechanics seem to confirm that the pterosaur pelvic and femoral musculoskeletal system is optimally configured for an erect stance.” 

But then he puts the fingers on the ground (Fig. 1). Why???

Perhaps Witton does not realize
what happens to his uropatagium when the pes is plantigrade, which is how Witton always reconstructs pterosaur pedes. Somehow he avoids drawing the lateral digit reversed toward the pelvis, as he proposed earlier.

Witton has no criticism
for one of his references, Hone and Benton 2007 (but did not cite the setup 2007 paper. Readers know, for many reasons, this is one of the worst papers ever published in this field. The facts will stun even freshmen paleontologists. 

Witton ignores the pterosaur sacrum,
which has more than the typical two sacrals found in a wide range of quadrupedal reptiles. Why does the pterosaur sacrum add and fuse vertebrae phylogenetically and more with larger taxa? For the same reason that humans, apes and theropod dinosaurs do. They are bipedal and the sacrum acts as the fulcrum to a long lever arm.

Earlier we talked about pterosaur workers wearing blinders, ignoring papers with hypotheses that conflicted with pet hypotheses. Now you see that happening in real time.

When workers, like Witton, stopped citing papers
I had published in academic journals is when I took my evidence and arguments online.

Earlier, in a multipart critique,
here, here, here, here and here we talked about Witton’s previously published work combined in a single book. I only wish someone with influence on Witton and his collaborators would remind them that their ideas and papers are going to end up like the Victorian-age cartoons they mock – unless they get back to facts and evidence.

References
Elgin RA, Hone DWE and Frey E 2011. The extent of the pterosaur flight membrane. Acta Palaeonntologica Polonica 56(1): 99-111.
Peters D 2002. 
A New Model for the Evolution of the Pterosaur Wing – with a twist. Historical Biology 15: 277–301.
Peters D 2011. A Catalog of Pterosaur Pedes for Trackmaker Identification
Ichnos 18(2):114-141. http://dx.doi.org/10.1080/10420940.2011.573605
Sharov AG 1971. New flying reptiles from the Mesozoic of Kazakhstan and Kirghizia. – Transactions of the Paleontological Institute, Akademia Nauk, USSR, Moscow, 130: 104–113 [in Russian].
Unwin DM and Bakhurina NN 1994. Sordes pilosus and the nature of the pterosaur flight apparatus. Nature 371: 62-64.
Witton MP 2015. Were early pterosaurs inept terrestrial locomotors? PeerJ 3:e1018 DOI 10.7717/peerj.1018

Pristidactylus: a Basiliscus sister without a crest

Figure 1. Pristidactlyus torquatus in vivo.

Figure 1. Pristidactlyus torquatus in vivo.

I got interested in the extant lizard, Pristidactylus
(Figs, 1, 2) when Bever and Norell 2017 used it as an outgroup to the clade Rhynchocephalia. The large reptile tree (LRT, 1122 taxa) using phylogenetic analysis falsifies that hypothesis of relationships.

Figure 1. Pristidactylus skull in 5 views. This iguanid lizard nests with the crested basilisk.

Figure 2. Pristidactylus skull in 5 views. This iguanid lizard nests with the crested basilisk.

Pristidacatylus torquatus (Phillippi 1861, extant, snout-vent length = 6-11cm) is the extant forest lizard. It is related to Basiliscus and feeds on beetles. Image from Digimorph.org.

Figure 3. Basiliscus, the "Jesus" lizard, does not share as many traits as Draco and Chlamydosaurus do, but is related, given the short list of Iguanids currently employed.

Figure 3. Basiliscus, the “Jesus” lizard, does not share as many traits as Draco and Chlamydosaurus do, but is related, given the short list of Iguanids currently employed.

Basiliscus basiliscus (Laurenti 1768) is the extant basilisk. It is related to Iguana but has a tall parietal crest. This frilled lizard is able to run bipedally across ponds. Skull image from Digimorph.org and used with permission.

References
Laurenti JN 1768. Specimen Medicum, Exhibens Synopsin Reptilium Emendatum cum
Experimentis Circa Venena et Antidota Reptilium Austriacorum. Wien.
Linnaeus C 1758. Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata.
Phillippi RA 1861. xx

wiki/Iguana
wiki/Basiliscus_(genus)