Tanystropheus: aquatic? or terrestrial?

Beard and Furrer 2017 conclude (or do they?)
that Tanystropheus (Figs. 1–3) was likely terrestrial.

From the abstract
“The Middle Triassic protorosaur Tanystropheus has been considered as both a terrestrial and aquatic taxon based on several lines of biomechanical and distributional evidence, but determining conclusively which habitat was most likely has remained problematic. The preservation of Tanystropheus was found to be more similar to Macrocnemus than Serpianosaurus implying carcasses of Tanystropheus originated in terrestrial or at least marginal and near-shore, shallow marine settings. That these were also the most probable habitats in life is supported by the relatively lower number of Tanystropheus (and also Macrocnemus) compared to Serpianosaurus.”

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.

Unfortunately,
Tanystropheus was not a protorosaur, nor a member of the Archosauromorpha. It was a tritosaur lepidosaur as taxon inclusion would have informed the authors.

Figure 2. Tanystropheus and kin going back to Huehuecuetzpalli.

Unfortunately,
the smaller Tanystropheus considered a juvenile by the authors was probably a different genus, based on a long list of distinct traits, including its distinct teeth. Moreover the authors did not realize that several large putative Tanystropheus specimens have distinct skull morphologies that are not congeneric (Fig. 2). But all that is beside the point…

Figure 3. Tanystropheus with skull reconstructions based on two specimens, exemplar i and exemplar m.

The authors report:
“An alternative aquatic lifestyle has also been suggested for Tanystropheus (Tschanz 1988). The main argument is the supposed inflexibility of the neck due to the elongated vertebrae and bundled cervical ribs that prevented all but a horizontal position (Tschanz 1988; Renesto 2005).”

Or any aquatic position,
including vertical (Fig. 1). The authors do cite the hooks from squid suckers found in the stomach region (Wild 1973; Fig. 1) and other prior hypotheses, then describe the taphonomy of the skeletons. The authors cite trackway data matched to Tanystropheus, (Fig. 3) ignoring the fact that even sea turtles leave trackways on beaches when they lay eggs.

Figure 3. Tanystropheus specimens matched to Synaptichnium tracks. The match is good in each case, except for one toe in each trackway. So, is this good enough? Or is this cause for dismissal?

Did the authors test the tracks?
No. But that is done here (Fig. 3). In each case there is a pretty good match—except for one toe in each case. The manus and pes have been scaled to match the tracks and thus are not matched to the scale bars which are for the tracks alone. Even so, the scale for the trackmakers’ extremities is a pretty good match! The case is not rock solid, but pretty good, that big and small tanystropheids made those Synaptichnium tracks.

Taphonomy 
The journey from the biosphere to the lithosphere was investigated. The terrestrial Ticinosuchus, a type of archosauriform, was discovered in these beds along with the aquatic Serpianosaurus, a type of pachypleurosaur, according to the authors (a basal thalattosaur in the large reptile tree). So was the tritosaur lepidosaur, Macrocnemus. The authors wondered if the taphonomy of Tanystropheus would be more similar to the terrestrial or the aquatic taxa. Wild (1973) listed and illustrated  over a dozen specimens of Tanstropheus in various stages of completeness and articulation. The water depth of fossil deposition was estimated between 30 and 130m with anoxic bottom conditions. So ALL the specimens were transported horizontally and vertically. Importantly, fragmentary skeletons of Tanystropheus were excluded from this study. From the remaining data the authors compiled articulation and completeness scores.

Why did they throw out competing data?
We’ve seen this before with Hone and Benton (2007, 2008). Given that they used only the more complete specimens (and who knows how many incomplete specimens were never collected), the authors report Tanystropheus specimens exhibited 0-58% articulation and 36–97% completeness. Larger specimens tended to be more complete. The authors also note that Serpianosaurus alone lacks obvious features that promoted buoyancy, like hollow cervicals in Tanystropheus. The authors cite Brand et al. 2003, who noted “lizard skin in water formed a limp but durable bag containing the bones” during water transport.

The authors conclude
“Tanystropheus langobardicus at least died in, but probably also lived in a terrestrial or near-shore marine setting.” The presence of squid hooks in the stomach “does not necessarily preclude a more-normal niche in shallow water.” 

‘Near shore marine’ = aquatic.
So the authors conclusion is no conclusion at all. Contra their headline, they did not ‘determine’ anything. It could have been on the beach, or in shallow water. Is the marine iguana (Amblyrhynchus cristatus) aquatic? or terrestrial? What would you say if you only found its skeleton? Or its footprints?

The good evidence continues to be
the stomach contents as the best evidence for life style (feeding niche) for the giant forms. Let the smaller ones feed in shallower waters. Let both give birth and warm up on land, like marine iguanas.

References
Bassani F 1886. Sui Fossili e sull’ età degli schisti bituminosi triasici di Besano in Lombardia. Atti della Società Italiana di Scienze Naturali 19:15–72.
Beard SR and Furrer 2017. Land or water: using taphonomic models to determine the lifestyle of the Triassic protorosaur Tanystropheus (Diapsida, Archosauromorpha). Palaeobiodiversity and Palaeoenvironments (advance online publication) DOI: https://doi.org/10.1007/s12549-017-0299-7
https://link.springer.com/article/10.1007/s12549-017-0299-7
Diedrich C 2008. Millions of reptile tracks—Early to Middle Triassic carbonate tidal flat migration bridges of Central Europe—reptile immigration into the Germanic Basin. Palaeogeography, Palaeoclimatology, Palaeoecology, 259, 410–423.
Haubold HA 1983. Archosaur evidence in the Buntsandstein (Lower Triassic). Acta Palaeontologica Polonica, 28, 123–132.
Li C 2007. A juvenile Tanystropheus sp.(Protoro sauria: Tanystropheidae) from the Middle Triassic of Guizhou, China. Vertebrata PalAsiatica 45(1): 37-42.
Meyer H von 1847–55. Die saurier des Muschelkalkes mit rücksicht auf die saurier aus Buntem Sanstein und Keuper; pp. 1-167 in Zur fauna der Vorwelt, zweite Abteilung. Frankfurt.
Nosotti S 2007. Tanystropheus longobardicus (Reptilia, Protorosauria: Reinterpretations of the anatomy based on new specimens from the Middle Triassic of Besano (Lombardy, Northern Italy). Memorie della Società Italiana di Scienze Naturali e del Museo Civico di Storia Naturale di Milano, Vol. XXXV – Fascicolo III, pp. 1-88
Peyer B 1931. Tanystropheus longobardicus Bass sp. Die Triasfauna der Tessiner Kalkalpen. Abhandlungen Schweizerische Paläontologie Gesellschaft 50:5-110.
Rieppel O, Jiang D-Y, Fraser NC, Hao W-C, Motani R, Sun Y-L & Sun ZY 2010. Tanystropheus cf. T. longobardicus from the early Late Triassic of Guizhou Province, southwestern China. Journal of Vertebrate Paleontology 30(4):1082-1089.
Wild R 1973. Die Triasfauna der Tessiner Kalkalpen XXIII. Tanystropheus longobardicus (Bassani) (Neue Ergebnisse). – Schweizerische Paläontologische Abhandlungen 95: 1-162 plus plates.

wiki/Tanystropheus

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SVP abstracts – Ennatosaurus

Romano et al. 2017

brings us a new reconstruction of Ennatosaurus (Fig. 1, btw – this is not it.)

Figure 1. An old reconstruction of Ennatosaurus, still not a synapsid, closer to millerettids and Eunotosaurus.

As you read the abstract,
bear in mind the only thing wrong here is the author’s insistence that Ennatosaurus is a pelycosaur and a synapsid. It is neither, as the addition of taxa to a cladistic analysis would have informed the Romano team. Ennatosaurus was derived from the similarly built milllerettids. This was demonstrated several years ago in the large reptile tree by the simple addition of taxa to the inclusion set.

From the abstract:
The Russian caseid Ennatosaurus tecton (Synapsida Caseasauria) is an important member of the group, being among the few “pelycosaurs” occurring in the Middle Permian, thus making caseids among the longest-surviving groups of non-therapsid synapsids. Although the cranial skeleton has been recently restudied in detail, the descriptions currently available for the postcranium are essentially limited to the original short account on the holotype provided by the original description from the 1950s. This contribution represents a new analysis of the postcranium of this taxon, using several different approaches. The postcranium of Ennatosaurus is informative with respect to both the taxonomy and phylogeny, with autapomorphic characters present particularly in the vertebral column. In addition, we conducted eight principal component analyses to investigate the position of the various appendicular elements of Ennatosaurus within the caseid morphospace. Members of all major groups of “pelycosaurs” were included in the morphometric analysis (along with selected outgroup taxa), allowing us to make some broader preliminary inferences regarding postcranial morphospace occupation of these basal synapsids for each individually-considered element. From the results of the principal component analyses, a major decoupling among the morphological patterns of stylopodial and zeugopodial elements is detected. Whereas femora and humeri exhibit a shared common pattern (with a wider overlap in their respective morphospace), the ulnae, radii, tibiae and fibulae show well-separated regions of morphospaces in the different clades. This result indicates the importance of such long bones also for taxonomic differentiation (in addition to their use for classical functional and biomechanical studies). Finally, a 3D photogrammetric model of the mounted specimen at the Paleontological Institute of Moscow has been used to obtain the first in vivo reconstruction of Ennatosaurus tecton, providing for the first time a potentially realistic picture of the Russian caseid in life.

For all this great work
resistance to taxon inclusion doomed any conclusions drawn. Sadly this basic problem is similar to workers who resist adding fenestrasaurs to pterosaurs studies, thalattosaurs to Vancleavea studies, tenrecs and desmostylians to whale studies, etc. etc…

References
Romano M, Brocklehurst N and Fröbisch J 2017. Redescription of the postcranial skeleton of Ennatosaurus tecton (Synapsida, Caseasauria, Caseidae) and its first in vivo restoration. Abstrcts from the 2917 meeting of the Society of Vertebrate Paleontology in Calgary.

Roof and floor, no walls: the skull of Aepyornis

Figure 1. The skull of Aepyornis is lacking lateral bones that help delineate fenestra, all of which are confluent.

Figure 2. Aepyornis maximus was the heaviest of all birds. Once considered a ratite, Aepyornis nests in the LRT with ducks, like Ana (Fig. 3).

Sure it looks like a giant ostrich,
but Aepyornis nests closer to geese and ducks. And let’s not forget that the basal duck, Presbyornis (Fig. 4), also had long, stork-like legs.

Aepyornis maximus (Geoffroy Saint-Hilaire) is the recently extinct elephant bird restricted to Madagascar. It is the heaviest of all birds and 3m tall. Long considered a ratite related to Struthio and especially Apteryx, here this taxon is recovered as a giant flightless goose. Note: all the fenestrae are confluent.

Figure 3. Anas, the mallard duck, shares more trait with Aepyornis than with other taxa in the LRT.

Anas platyrhynchos (Linneaus 1758) is the extant mallard duck. It has shorter legs than Presbyornis. This toothless bird has toothlike serrations on the keratin that covers its broad bill.

Figure 4. Presbyornis is the prehistoric long-legged duck, close to the elephant bird, Aepyornis.

Presbyornis pervetus (Wetmore 1926; Olson and Feduccia 1980; earliest Eocene, 62 mya) is one of the first of the clade Anseriformes (ducks, geese and kin). It is known from scattered bones and was originally considered a flamingo relative, due to its long legs. The duck-like skull was found later. This clade is the sister to the predatorial long-legged taxa, like Cariama and Sagittarius.

References
Geoffroy Saint-Hilaire I 1851. [Note sur les onze espèces nouvelles do Trochilidés de M. Bourcier.] Compt. Rend. de l’Acad. Sci 32:188.
Linnaeus C 1758. Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata.
Olson SL and Feduccia A 1980. Presbyornis and the origin of the Anseriformes (Aves: Charadriomorphae). Smithsonian Contributions to Zoology 323: 1–24.
Wetmore A 1926. Fossil birds from the Green River deposits of Eastern Utah. Annals of the Carnegie Museum 16: 391-402.

wiki/Anas
wiki/Presbyornis
wiki/Aepyornis

SVP abstracts 2017: The earliest lepidosaurs

Simöes 2017 brings us
new insights into the origin and early radiation of lepidosaurs, but seems to focus on the squamate side of that equation. Earlier Simöes brought us new data on Ardeosaurus (late Jurassic proto-snake) and Calanguban (Early Cretaceous, late-surviving basal squamate).

From the abstract:
“The origins and early radiation of lepidosaurs remain largely enigmatic by several factors, including:

1. the oldest unequivocal fossils currently attributed to the Squamata are from the Middle Jurassic;
2. available studies of broad level/deep-time diapsid reptile relationships provide very limited sampling of either fossil or living lepidosaurs (often, Squamata being represented as a single terminal unit);
3. morphological and molecular evidence of squamate relationships disagree on what is the earliest squamate clade (iguanians vs dibamids and geckoes);
4. among others.”

“Here, I provide a new phylogenetic dataset with a deep sampling of the major diapsid and
lepidosaurian lineages (living and fossil) at the species level in order to identify the
composition and early evolution of lepidosaurs. All taxon scorings were based on
personal observation of specimens and/or 3D CT scans from 51 collections from around
the world, making it the largest species sample ever collected for investigating the origin
of lepidosaurs—over 150 species.”

“The results indicate novel relationships among diapsids and re-shape the lepidosaurian
tree of life. Previously proposed early lepidosaurs are found to belong to other lineages of
reptiles. Importantly, heretofore unrecognized squamate fossils are found as the earliest
squamates, dating back to the Early Triassic, thus filling what was thought to be a fossil
gap of at least 50 million years. In most results (morphology only and combined data)
geckoes are the earliest squamate crown clade, iguanians are always found as later
evolving squamates, and scincomorphs are polyphyletic, thus dramatically differing from
previous morphology based studies, but agreeing with the molecular data.”

Figure 1. Lacertulus, a basal protosquamate from the Late Permian

How does this data compare
to the large reptile tree? The LRT has 140 lepidosaur taxa, but I don’t get the feeling that Simöes included tritosaurs and protosquamates, some of which extend back to the Late Permian (Lacertulus, Fig. 1). If Simöes does not include those clades, the hypothesis needs more taxa. The abstract is enigmatic with regard to which early lepidosaurs now belong to other lineages and which unrecognized squamates are now earliest squamates.

But I like that Simöes is looking at more taxa!!

Unfortunately,
Simöes does not provide outgroup taxa in the abstract. I’m guessing he did not test a wide gamut of taxa, like the LRT, to see if they were lepidosaurs or not. That’s how you recover protosquamates and tritosaurs. In the LRT geckoes are not the basalmost squamates and scincomorphs are not polyphyletic.

I look forward to this paper!!

References
Simöes TR 2017. The origin and early evolution of lepidosaurian reptiles. Abstracts from the Society of Vertebrate Paleontology 2017.

Adding more birds to the LRT

Over the last week or so
more birds have been added to the large reptile tree (LRT, 1074 taxa, subset Fig. 1). Many are still with us. Others are recently extinct. Still others are known only from the Paleocene.

Figure 1. Subset of the LRT focusing on extant birds and their closest kin.

I was surprised to see

1. the toothed birds, Yanornis, Ichthyornis and Hesperornis nest within the clade of extant birds. That means, like Pelagornis, some sort of teeth came back.
2. the moa, DInornis and Gastornis (= Diatryma) both nest close to parrots (like Ara) and the hoatzin (Opisthocomus). Here ratites are no longer monophyletic. Wikipedia notes, “The systematics involved have been in flux.”
3. ducks, like Anas, are close to predatory birds, like Sagittarius
4. the Solnhofen bird, Jurapteryx (= Archaeopteryx) recurva nests at the base of the clade of extant birds
5. Details later.

Splitting up the Palaeognathae

Distinct from earlier DNA and morphological studies
members of the Euornithes (extant birds and their closest kin) are undergoing tree topology shifts when they enter the large reptile tree (LRT, 1076 taxa). We’ve seen this before with other reptile and mammal clades.

Today we’ll be talking about
the base of the Euornithes, the ratites and tinamous (= Palaeognathae).

Ratites have no keel on their sternum.
But that keel fails to appear on several flightless birds in several clades. Wikipedia reports, “Flightlessness is a trait that evolved independently multiple times in different ratite lineages. The systematics involved [in the ratites] have been in flux.”

Wikipedia reports,
“There are three extinct groups [of Palaeognathae], the Lithornithiformes (Lithornis + Pseudocrypturus.), the Dinornithiformes (moas) and the Aepyornithiformes (elephant birds), that are undisputed members of Palaeognathae.” 

Disputing those traditional assignments,
in the LRT (Fig. 1):

1. the moa, DInornis, nests with parrots
2. the elephant bird, Aepyornis, nests with ducks.  

When I added
the kiwi Apteryx Fig. 2) and elephant bird (Aepyornis (Fig. 3) to the LRT a monophyletic clade(?) Ratites + tinamous (= Palaeognathae; pink taxa in Fig. 1) was not recovered. The remaining ratites are not a clade, but a grade of basal birds with tinamous, like Rhynchotus, nesting basal to and the proximal outgroup to the clade Neognathae.

And yes, the Solnhofen bird
Jurapteryx recurva (= Eichstätt specimen of Archaeopteryx) is the basalmost member (= last common ancestor) of the Euornithes. That means, someday we’ll be finding palaeognathid ostrich, cassowary and tinamou ancestors in the Early and Late Cretaceous. That has not happened yet (to my knowledge).

Currently filling this Cretaceous gap
are the toothed birds Yanornis, Apsaravis, Ichthyornis and Hesperornis. They now nest within the Euornithes (the clade of extant birds). Evidently teeth redeveloped in this clade as they did in Pelagornis, the giant albatross-like bird with bony teeth. Earlier we looked at the reappearance of digit ‘0’ in screamers, so old genes can and do reassert themselves in birds.

Without this clade of toothed Cretaceous birds
there would have been, a long Cretaceous gap in the fossil record of Euornithes. I’m sure this gap will be filled someday with toothless birds. When it is filled phylogenetic bracketing indicates they’re going to look like dippers, like Cinclus, and screamers, like Chauna. As mentioned earlier, this gap is currently not filled, nor even hinted at (Fig. 1).

Figure 2. Jurapteryx, Pseudocrypturus, Apteryx and Proapteryx to scale. Now we know why the gastralia disappeared in this clade!

When you put both Pseudocrypturus and Apteryx together
to scale (Fig. 2) the several reasons (traits) why they nest together become more obvious. This is contra recent DNA studies that nest elephant birds with kiwis (Mitchell et al. 2014). That study represents one more incidence of the loss of validity with DNA over large phylogenetic distances along with the typical problem of taxon exclusion that the LRT attempts to minimize.

Archaeopteryx (Jurapteryx) recurva 
(JM2257; the Eichstätt specimen; Howgate 1985) is one of the smaller Solnhofen birds. Here it nests as the last common ancestor of all extant birds. A gap spanning the entire Cretaceous separates this taxon from extant taxa and their kin. As in other bird lines, the loss of tail length, the fusion of the pygostyle and the fusion of manus elements are convergent.

Pseudocrypturus cercanaxius 
(Houde 1988; Early Eocene) was originally considered a northern hemisphere ancestor to ratites (like the ostrich, Struthio). That is true, but Pseudocrypturus is also close to the ancestry of all extant birds. Today primitive flightless birds are chiefly restricted to the southern hemisphere. It could be that early birds did start in the South and had migrated to the North during the Paleocene (66-56 mya) or earlier. Perhaps something very much like it was one of the few survivors of the K-T extinction event.

It’s notable that Pseudocrypturus has long legs. Early ducks, like Presbyornis, and basal raptors, like Sagittarius, also had long legs. Evidence is building that this is the primitive condition for the clade of living birds arising from the K-T extinction event.

Apteryx 
(Shaw 1813) The extant flightless kiwi has an elongate naris that extends to the tip of its beak. Maybe two teeth are there. Here it nests with Pseudocrypturus, but flightless traits linking it toward Struthio are by convergence. In the pre-cladistic era, Calder (1978, 1984) considered the kiwi a phylogenetic dwarf derived from the larger moa, but that was invalidated by Worthy et al. 2013 and the LRT.

Note that
Proapteryx (Worthy et al. 2013; Miocene), known from a partial femur and coracoid, falls within the size range of Jurapteryx (Late Jurassic). Proapteryx likely was volant.

References
Calder WA 1978. The kiwi. Scientific American 239(1):132–142.
Calder WA 1984. Size, function and life history. 448 pp. Cambridge (Harvard U Press).
Houde PW 1986. Ostrich ancestors found in the northern hemisphere suggest new hypothesis of ratite origins. Nature 324:563–565.
Houde PW 1988. Paleognathus birds from the early Tertiary of the northern hemisphere. Publications of the Nuttall Ornithological Club 22. 147 pp.
Howgate ME 1985. Problems of the osteology of Archaeopteryx: is the Eichstätt specimen a distinct genus?. In Hecht, Ostrom, Viohl, and Wellnhofer (eds.), The Beginnings of Birds: Proceedings of the International Archaeopteryx Conference, Eichstätt 1984. Freunde des Jura-Museums Eichstätt, Eichstätt 105-112.
Mitchell KJ (seven coauthors) 2014. Ancient DNA reveals elephant birds and kiwi are sister taxa and clarifies ratite bird evolution. Science. 344 (6186): 898–900.
Shaw 1813. Naturalist’s Miscellany 19:
Worthy TH et al. 2013. Miocene fossils show that kiwi (Apteryx, Apterygidae) are probably not phyletic dwarves. Paleornithological Research 2013, Proceedings of the 8th International Meeting of the Society of Avian Paleontology and Evolution.

wiki/Jurapteryx
wiki/Pseudocrypturus
wiki/Apteryx, Kiwi
wiki/Proapteryx
wiki/Dipper
wiki/Proapteryx

SVP abstracts 2017: The enigmatic New Haven Reptile

Pritchard et al. 2017
introduce the concepts of a ‘pan-archosaur’ and a ‘pan-lepidosaur’ as they describe the small, enigmatic “New Haven Reptile” (Latest Triassic; 2.5cm skull length).

From the Pritchard et al. abstract:
“The fossil record of early-diverging pan-archosaurs and pan-lepidosaurs in the Triassic is biased towards large-bodied animals (1+ meters). The Triassic Newark Supergroup of eastern North America has produced tantalizing specimens of small reptiles, hinting at high diversity on the continent. Among these is a remarkable diapsid skull (~2.5 cm length) lacking teeth and a mandible, from the Upper Triassic New Haven Arkose of Connecticut that has been referred to as one of the oldest sphenodontians from North America (referred to herein as the New Haven Reptile). 

“Following further preparation, we re-assessed the affinities of the New Haven Reptile using three-dimensional reconstruction of microCT data. The ontogenetic state of the New Haven Reptile is uncertain; despite the extensive reinforcement of the skull, the skull roof exhibits a large fontanelle between frontals and parietals. The feeding apparatus of this species is distinct from most small-bodied Triassic diapsids, with a strongly reinforced rostrum, a narrow sagittal crest on the parietals, and transverse expansion of postorbitals and jugals. The latter two conditions suggest transverse expansions of deep and superficial adductor musculature in a manner very similar to derived Rhynchosauria. This may suggest a specialized herbivorous diet similar to rhynchosaurs, although the New Haven Reptile is smaller than most modern herbivorous diapsids. 

“A phylogenetic analysis suggests that the New Haven Reptile is not a sphenodontian but an early pan-archosaur, representing a distinctive and previously unrecognized lineage. Regardless of its affinities, the New Haven Reptile differs from other small-bodied Triassic Sauria in its hypertrophied jaw musculature suggesting a greater dietary specialization in these taxa than previously understood. It underscores the importance of geographically undersampled regions in understanding the true ecomorphological diversity in the fossil record.”

So, what is the New Haven reptile?
Without seeing the fossil or the presentation, we start with what was offered:

1. a small taxon (skull = 2.5cm)
2. like a sphenodontian, diapsid temporal openings
3. lacking teeth
4. extensive reinforcement of the skull
5. large fontanelle between frontals and parietals (pineal?)
6. strongly reinforced rostrum
7. a narrow sagittal crest on the parietals
8. transverse expansion of postorbitals and jugals, like rhynchosaurs
9. hypertrophied jaw musculature

Figure 1. Priosphenodon model. Is this what the New Haven Reptile looked like? Note the dorsal fontanelle, the pineal opening that largely disappears in rhynchosaurs. 

This sounds like
Priosphenodon avelasi, (Figs. 1, 2) which is a transitional taxon more derived than sphenodontians and more primitive than rhynchosaurs. The only skull known to me is about 8cm in length, or 3x larger than the New Haven Reptile. Priosphenodon was a late-surviving Cenomian, Cretaceous taxon, more derived  than the even later-surviving extant taxon, Sphenodon.

Figure 2. Priosphenodon nests closer to rhynchosaurs than Mesosuchus does, yet it was not included in the Ezcurra et al. 2016 study.

If my guess is valid,
its no wonder that Pritchard et al. are confused. To them rhynchosaurs are not related to sphendontians. These fellow workers need to include more taxa in their analysis and a suggested list is found at the large reptile tree (LRT, 1069 taxa). 

If it is something different
please send an image or publication and I will add it to the LRT.

References
Pritchard AC, Bhullar B-A S and Gauthier JA 2017. A tiny, early pan-archosaur from the Early Triassic of Connecticut and the diversity of the early saurian feeding apparatus. SVP abstracts 2017.