My what big eyes you have, Lyriocephalus!

Looking like some sort of medieval fever dream,
meet Lyriocephalus, the hump-nosed lizard (Fig. 1), a cousin to Draco, the gliding lizard. Distinct from Draco, the body of this insectivore is laterally compressed, not laterally extended.

Figure 1. Lyriocephalus in vivo.

Figure 1. Lyriocephalus in vivo.

Probably the largest eyes
relative to the skull of any tetrapod. Lyriocephalus, is an arboreal jungle lizard with an anterodorsal naris and a small antorbital fenestra. Note the arching postorbital contacting the prefrontal.

Figure 2. Lyriocephalus skull in several views. Note the arching of the postorbital to contact the prefrontal.

Figure 2. Lyriocephalus skull in several views. Note the arching of the postorbital to contact the prefrontal. And did I mention that antorbital fenestra?

Lyriocephalus scutatus (Merrem 1820) is represented by a skeleton at Morphospace.org where you can rotate the skeleton on your monitor. Note the brevity of the tail of this agamid iguanid, There are more in vivo pix here. And a video here.

Figure 3. Lyriocephalus skeleton from Morphobank.org, where you can rotate digitized skeletons.

Figure 3. Lyriocephalus skeleton from Morphobank.org, where you can rotate digitized skeletons.

References
Merrem B 1820. Versuch cines Systems Amphihien Tentamen Systcmatis Amphibiorum. Marburg, Krieger.

wiki/Draco
wiki/Lyriocephalus

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.
Philippi RA and Landeck L 1861. Neue Wirbelthiere von Chile. Archiv für Naturgeschichte 27 (1): 289-301.

wiki/Iguana
wiki/Basiliscus_(genus)

Mid-Cretaceous lizards in amber from Myanmar

A new paper
from Daza et al. (2016) brings us several lizards in amber from the Mid Cretaceous (Fig. 1).

Figure 1. Mid-Cretaceous lizards in amber from Daza et al. 2016. Highlighted specimens are examined here.

Figure 1. Mid-Cretaceous lizards in amber from Daza et al. 2016. Highlighted specimens are examined here.

I was chiefly interested in
the unidentified ones, JZC Bu267 (Fig. 2) and JZC Bu1803 (Fig. 4).

Figure 2. JZC Bu 267 nests with the pre-snake, Jucarseps in the large reptile tree.

Figure 2. JZC Bu 267 nests with the pre-snake, Jucarseps in the large reptile tree.

JZC Bu 267
is a tiny, slender, short-legged, long-toed lizard that nests with the Early Cretaceous pre-snake, Jucarseps, (Bolet and Evans 2012, Fig. 3) in the large reptile tree. This nesting is based on relatively few traits as the skull is largely missing while dermis covers large portions of the post-crania. The two are about the same size and overall proportions.

The authors report, “The preservation of  JZC Bu267 is exceptional; it includes the epidermis and soft tissues and even a unique extended tongue tip with a narrow medial projection that does not resemble the form of any described squamate tongues.” According to Wikipedia, reptiles developed forked tongues in several clades independently.

Figure 1. Jucaraseps in situ. This tiny long lizard is in the lineage of terrestrial snakes.

Figure 3. Jucaraseps in situ. This tiny long lizard is in the lineage of terrestrial snakes and nests as a sister to JZC Bu 267,

So this find
extends the range of the Jucarseps clade from SW Europe to SE Asia.

Figure 4 JZC-Bu1803 has a relatively large skull. This and other traits nest it with the basal scleroglossan, Calanguban in the large reptile tree.

Figure 4 JZC-Bu1803 has a relatively large skull. This and other traits nest it with the basal scleroglossan, Calanguban in the large reptile tree.

JZC Bu1803
(3.2cm snout vent length) Is more thoroughly covered in fine scales. Nevertheless, a large enough list of traits was gleaned from the photo to nest JZC Bu 1803 with the basal scleroglossan, Calanguban (Simoes, Caldwell and Kellner 2014, Early Cretaceous), which is also the same size.

According to Daza et al. “The ventral scales are large, quadrangular, and arranged in regular transverse and longitudinal rows as in most living teiids and lacertids. Remarkable features of this specimen are the extremely long digits and claws.

“A digital endocast of the leftmaxilla exposed the entire tooth row section, a dentition including about 14 functional teeth, and an estimated 19 tooth loci. Tooth attachment is pleurodont and morphology is heterodont, with an abrupt transition from conical and recurved teeth (first 12) to tricuspid (with divided crowns, last 7). Tricuspid (or triconodonot) dentition is widespread among squamates. Among extant groups, the combination of anterior fang-like and posterior tricuspid teeth with parallel margins, where mesial and distal cusps are shorter than the main apex,most closely resembles that of lacertids and teiids.”

Figure 4. Calanguban nests as a sister to JZC Bu 1803 in the large reptile tree.

Figure 5. Calanguban nests as a sister to JZC Bu 1803 in the large reptile tree.

So this find
extends the range of the Calanguban clade from SW Europe across the then narrow Atlantic to NE Brazil.

Figure 6. The two new and unidentified amber embedded specimens nest as squamates that already have names here.

Figure 6. The two new and unidentified amber embedded specimens nest as squamates that already have names here.

The authors indicate
that more data will be forthcoming on these specimens. More can be seen on YouTube here.

References
Bolet A and Evans SE 2012. A tiny lizard (Lepidosauria, Squamata) from the lower Cretaceous of Spain. Palaeontology 55:491-500.
Daza J, Sanley EL, Wagner P, Bauer A and Grimaldi DA 2016. Mid-Cretaceous amber fossils illuminate the past diversity of tropical lizards. Science Advances 2(3): e1501080. DOI: 10.1126/sciadv.1501080
Simoes TR, Caldwell MW and Kellner AWA 2014.
 A new Early Cretaceous lizard species from Brazil, and the phylogenetic postion of the oldest known South American squamates. Journal of Systematic Palaeontology. http://dx.doi.org/10.1080/14772019.2014.947342

YouTube with rotating scans

 

 

 

 

The other Slavoia and the holotype

Earlier we looked at the basal amphisbaenid, Slavoia darevskii (Fig. 3 below, Talanda 2015).

I just read about the holotype (Sulminski 1984) and at least 45 other specimens attributed to Slavoia, like this one (Fig. 1, ZPAL MgR-III/77, Campanian, Late Cretaceous). Six of the 46 skulls are associated with postcranial skeletons, like the holotype, Fig. 2, ZPAL MgR-I/8). If you think this skull looks like Macrocephalosaurus, you’re not the only one.

Slavoia specimen ZPAL MgR III/77 nests not with amphisbaenids, but with Macrocephalosaurus, a contemporary from the same horizon.

Slavoia specimen ZPAL MgR III/77, one of 46 skulls,  nests not with amphisbaenids, but with Macrocephalosaurus, a contemporary from the same horizon. Talanda reports, “The specimen has only half of the elements visible in this drawing. The skull roof and the middle part are not preserved.”

Sulminski nested Slavoia with scincomorphan lizards, but he reported, “It is interesting that described here lizard displays some characters similar to macrocephalosaurid and polyglyphanodontid  species discovered in the same localities of Mongolia. This concerns also particularly the structure of the temporal region, palatal construction and in number of teeth.”

The #77 and #8 specimens nested with macrocephalosaurs in the large reptile tree.

On the other hand,
the #112 specimen nested at the base of the amphisbaenids, as we learned earlier. So the #112 specimen needs a new generic name, or there are other issues that need be dealt with.

Dragging
the amphisbaenid #112 specimen over to the macrocephalosaur specimens adds 17 steps to the most parsimonious tree score. That’s a very low number considering that there are only 17 taxa separating the macrocephalosaurs from the amphisbaenids in the large reptile tree. So, there is a bit of convergence going on here between the macrocephalosaurids and amphisbaenids. The authors note all the skulls vary in size and shape, which they attribute to ontogeny and intraspecific variation. And, of course, none are perfectly preserved. Talanda reports, “The [#77] specimen has only a half of the elements visible in this drawing. The skull roof and the middle part are not preserved.”

Figure 2. The holotype of Slavoia (#8) compared to the lateral view skull (#77). While larger, the #77 skull is relatively shorter. These two nest together in the large reptile tree along with macrocephalosaurids.

Figure 2. The holotype of Slavoia (#8) compared to the lateral view skull (#77). While larger, the #77 skull is relatively shorter. These two nest together in the large reptile tree along with macrocephalosaurids. Note the large size of the limbs.

Does this represent a solution?
Sulimski (1984) recognized the similarity between his skinks and macrocephalosaurids. Talanda (2015) considered his specimen a basal amphisbaenid, a clade derived from skinks in the large reptile tree, but Talanda nested his amphisbaenids between Cryptolacerta and Dibamus + snakes. So there is disagreement here.

Figure 1. basal amphisbaenid Slavoia from Talanda 2015, showing in situ fossil, tracing by Talanda and colorizing added here. Several bones, like the lacrimal and prefrontal, are missing in the Talanda tracing, which evidently was not traced from this photograph.

Figure 3. The #112 specimen from Talanda 2015 which both he and I nested as a basal amphisbaenid. Note the similarity to macrocephalosaurids (above). The teeth appear to be more robust here, as they are in the palate view specimens that have more of an amphisbaenid palate. I don’t see large limbs here, but limb size varies in the amphisbaenids.

Phylogeny is sometimes simple and straightforward.
Sometimes it is not.

This case shows the importance
of using specimen-based taxa in analyses, not specific, generic or suprageneric taxa. It would not be okay to take the best traits from several Slavoia specimens because some may not be Slavoia specimens! This case also highlights a need to determine where every one of these varied Slavoia specimens do nest. And it will be okay if some are lumped while others are split.

The limbs are large in the #8 specimen, but are not visible in the #112 specimen. In amphisbaenids limbs, even in basal taxa, can be vestiges, but not vestiges in the very derived Bipes.

We all have a lot to learn here. It’s not all set in stone.

References
Sulimski A 1984. A new Cretaceous scincomorph lizard from Mongolia. Palaeontologia Polonica, 46, 143–155.
Talanda M 2015.
 Cretaceous roots of the amphisbaenian lizards. Zoologica Scripta. doi:10.1111/zsc.12138

Reconstruction from jumbled scraps: the squamate, Kuroyuriella

Figure 1. The skull of Kuroyuriella reconstructed from bone scraps (above), most of which are layered on top of one another. Not all elements are identified, but enough are to nest this taxon with Ophisaurus.

Figure 1. The skull of Kuroyuriella (represented by two specimens of different size) reconstructed from bone scraps (above), most of which are layered on top of one another. Not all elements are identified, but enough are known to score and nest this taxon with Ophisaurus.

When provided disarticulated scraps,
start with the easy bones, then fill in the gaps in the puzzle. Sometimes, as in Kuroyuriella mikikoi (Evans and Matsumoto 2015, Early Cretaceous), there are enough parts to more or less recreate the skull most similar (among tested taxa in the large reptile tree) to that of Ophisaurus and basal to Myrmecodaptria and CryptolacertaEvans and Matsumoto nested Kuroyuriella  between Huehuecuetzpalli and the suprageneric clade Rhynchocephalia, both well outside the Squamata.

From the online paper:
“Together, SBEI 1510 and SBEI 1608, as type and referred specimen, characterize Kuroyuriella mikikoi as a small lizard having paired frontals with deep subolfactory processes; a median parietal without a parietal foramen, with sculpture of low relief, and with lateral shelves that restricted the adductor muscle origins to the ventral surface; upper temporal fenestrae that were at least partially closed by expanded postorbitofrontals; an unsculptured maxilla with a strongly concave narial margin; a large flared prefrontal; and a slender, relatively small pterygoid. In the shallow lower jaw, the teeth are closely packed, cylindrical, and pleurodont with lingual replacement; a subdental ridge is present; the dentary bears a tapering coronoid process that braces the coronoid, and has a posterior extension with a curved free margin; the surangular, angular, and splenial are all present and the surangular is shallow; the adductor fossa is open but not expanded; and the articular surface is asymmetrical.

In order to explore the affinities of Kuroyuriella mikikoi, it was coded into the matrix of Gauthier et al. (2012), as extended by Longrich et al. (2012) (184 characters coded out of 622, 70.4% missing data),

The consistent placement of Kuroyuriella on the squamate stem is problematic and probably artifactual, but whether the weighted analysis is giving a more accurate placement is uncertain. Of the derived character states possessed by Kuroyuriella, 76 [1] (postorbital partly occludes upper temporal fenestra), 364 [1] (dentary coronoid process extends beyond level of coronoid apex), 367 [2] (coronoid process of dentary overlaps most of anterolateral surface of coronoid), and 369 [2] (dentary terminates well posterior to coronoid apex) provide some support for placement of Kuroyuriella on the stem of scincids, and 129 [1] (prefrontal extends to mid-orbit), 104 [1] (absence of parietal foramen) and 385 [1] (posterior mylohyoid foramen posterior to coronoid apex) would be consistent with that placement. However, given the considerable difference between the results using equal weighting and Implied Weighting, Kuroyuriella remains incertae sedis pending recovery of more complete material.”

Figure 2. Ophisaurus, the extant glass snake or legless lizard is close to Kuroyuriella in the large reptile tree.

Figure 2. Ophisaurus, the extant glass snake or legless lizard is close to Kuroyuriella in the large reptile tree.

Here
Ophisaurus (Fig. 2) and Kuroyuriella both nest will within the Squamata, not ouside. of it in the large reptile tree. Reconstruction of the skull helps to ‘see’ this lizard as it was. I can’t imagine how difficult it would be to do try to establish traits  with a jumble of disarticulated bones.

As you’ll see, I think the parietal foramen was present. The parietal may have had longer posterior processes, now broken off.

References
Evans SE and Matsumoto R 2015. An assemblage of lizards from the Early Cretaceous of Japan. Palaeontologia Electronica 18.2.36A: 1-36
palaeo-electronica.org/content/2015/1271-japanese-fossil-lizards
http://palaeo-electronica.org/content/2015/1271-japanese-fossil-lizards

Sirenoscincus mobydick: the only terrestrial tetrapod with ‘flippers’

Sakata and Hikida 2003
introduced us to a new and extant fossorial (burrowing) lizard (Sirenoscincus yamagishii. Fig.1). The authors described having “an elongated body and eyes covered by scales, lacking external ear openings and pigmentation through- out the body, resembles Cryptoscincus and Voeltzkowia. However it differs from these or any other scincid genera known to the present in having small but distinct forelimbs, each with four stout claws, and complete lack of hind limbs.”

Figure 1. Sirenoscincus-yamagishii, a new skink with forelimbs and no hind limbs. Note the four fingers.

Figure 1. Sirenoscincus-yamagishii, a new skink with forelimbs and no hind limbs. Note the four fingers.

Sirenoscincus is a very tiny lizard
with 53 presacral vertebrae and a tail longer than the snout vent length. The snout is pointed and the lower jaw is countersunk, like a shark’s mouth. The forelimbs are tiny with indistinct fingers and four stout claws. An outgroup taxon, Gymnophthalmus, also has tiny fingers and the medial one is a vestige.

Then a second Sirenoscincus species was discovered
S. mobydick (Miralles et al. 2012, Fig. 2; see online interview here). “The specicific epithet refers to Moby Dick, the famous albino sperm whale imagined by Herman Melville (1851), with whom the new species shares several uncommon characteristics, such as the lack of hind limbs, the presence of fipper-like forelimbs, highly reduced eyes, and the complete absence of pigmentation.”

Figure 3. Sirenoscincus mobydick.

Figure 2. Sirenoscincus mobydick.

S. mobydick has only five scleral ring bones, the lowest of any lizard. The authors reinterpreted several scale patterns on the holotype species. So, mistakes do happen, even at a professional level. Those mistakes get corrected and no one gets upset (hopefully unlike the blogosphere!).

Figure 2. Sireonscincus mobydick, named for its flippers, unique for any terrestrial tetrapod.

Figure 3. Sireonscincus mobydick, named for its flippers, unique for any terrestrial tetrapod. Colors added.

Fossorial skinks are often described by their scale patterns.
Unfortunately that doesn’t work with prehistoric skeletons, so I was only able to add only the bone traits of Sirenoscincus mobydick to the large reptile tree (subset shown in Fig. 7). The skeletal traits nested S. mobydick between two skinks Gymnophthalmus and Sineoamphisbaena, another taxon with forelimbs only (granted, the posterior half is not known). Like Sineoamphisbaena, Sirenoscincus prefrontals contact the postfrontals, unlike those of most lizards. In derived taxa the quadrate leans almost horizontally. That’s not the case with Sirenoscincus, which has a vertical but bent quadrate.

Figure 4. Sirenoscincus mobydick pectoral and pelvic girdles. Colors added.

Figure 4. Sirenoscincus mobydick pectoral and pelvic girdles. Colors (other then the original red) are added here.

Miralles et al. (2012) reported,  “Due to the absence of molecular data the phylogenetic position of the genus Sirenoscincus is still an enigma, even if we can reasonably claim it belongs to the Malagasy scincine clade.” In the last few days author, A. Miralles reported via email that molecular data have recently nested S. mobydick with skinks. 

Figure x. Chalcides guentheri and C. occellatus, two skinks were morphology quite similar to that of Sirenoscincus.

Figure 5. Chalcides guentheri and C. occellatus, two skinks with morphologies quite similar to that of Sirenoscincus. C. oscellatus has longer legs. Note the wrapping of the maxilla over the premaxilla which is continued in Sirenoscincus mobydick which has a smaller orbit. Also note the prefrontal and postfrontal are closer to contact in C. ocellatus.

An outgroup taxon is Chalcides (Fig. 5) where you’ll note the same long overlap of the maxilla over the premaxilla. A sister, Sineoamphisbaena also has an underslung mandible, but much more robust forelimbs (only the humerus is known). Could this be a redevelopment? Or has the cladogram missed something, needing more taxa perhaps, to fill this gap? No doubt new taxa will fill these various morphological gaps.

Figure 6. Sineoamphisbaena is a sister to Sirenoscincus in which the prefrontal contacts the postfrontal.

Figure 6. Sineoamphisbaena is a sister to Sirenoscincus in which the prefrontal contacts the postfrontal. The lower jaw is countersunk and the upper teeth don’t point down, they point in (medially).

New data has revised the relationship of skinks to reptiles in the large reptile tree (Fig. 7). Some to most of the confusion (here or earlier) likely results from the massive convergence in burrowing lizards. And some portion is also due to having good data (old line drawings) replaced by better data (rotating online images), often thanks to the good scientists over at Digimorph.org.

Figure 7. Here's where Sirenoscincus nests in the lizard family tree.

Figure 7. Here’s where Sirenoscincus nests in the lizard family tree.

References
Miralles A et al. 2012. Variations on a bauplan: description of a new Malagasy “mermaid skink” with flipper-like forelimbs only (Scincidae, Sirenoscincus Sakata & Hikida, 2003). Zoosystema 34(4):701-719.
Sakata S and Hikida T 2003. A fossorial lizard with forelimbs only: description of a new genus and species of Malagasy skink (Reptilia: Squamata: Scincidae). Current Herpetology 22:9-15.

Have you ever seen an Anolis quite like this?

This is a striking variation on the Anolis lizard theme with an extended premaxilla/snout. Meet Anolis proboscis, aka the Pinocchio lizard. This trait is restricted to males and this species was thought to be extinct for several decades. Click here or on the image to learn more.

Figure 1. Long-nosed Anolis from the Luke Mahler lab.

Figure 1. Long-nosed Anolis from the Luke Mahler lab. Only males have this trait.  Click to learn more.

The image comes from the Luke Mahler website. Dr. Mahler is a former student of Jonathan Losos, now at Harvard, formerly of Washington University, here in St. Louis. Jonathan’s work with Anolis has shed new light on the process of evolution.

References
Poe et al. 2012.
Morphology, Phylogeny, and Behavior of Anolis proboscis. Breviora Number 530 :1-11. 2012 online here and here.

Not Bavarisaurus?

Conrad (2014) reports
The lizard ingested by Compsognathus  (Fig. 1) is a new species, not congeneric with the holotype of Bavarisaururus macrodactylus (= Homoeodactylus macrodactylus, Wagner 1852). That is verified here.

Figure 1. Click to enlarge. The little Jurassic lizard Bavariasaurus was found inside the belly of the little Jurassic dinosaur, Compsognathus. But it is not the same genus as the holotype.

Figure 1. Click to enlarge. The little Jurassic lizard Bavariasaurus was found inside the belly of the little Jurassic dinosaur, Compsognathus. But it is not the same genus as the holotype.

From the Conrad (2014) abstract:
“Bavarian limestone deposits represent some of the few areas preserving articulate Jurassic squamates. Bavarisaurus, two species of Eichstaettisaurus, and Ardeosaurus have been recognized from those deposits. Although usually identified as Bavarisaurus macrodactylus or Bavarisaurus cf. macrodactylus, a lizard preserved as a cololite in the theropod Compsognathus longipes shows important differences from the type specimen of Bavarisaurus macrodactylus. This cololite lizard specimen (hereafter, ‘cololizard’) is preserved as a combination of bone and bone-impressions, some of which are extremely clear. The skull preserves the premaxilla, maxilla, prefrontal, frontal, parietal, postfrontal, jugal, pterygoid, ectopterygoid, and mandible. The humerus and much of the thoracic skeleton, tail, pelvis, and hind limb are preserved. Comparative studies demonstrate that the ingested form is a new species. A cladistic analysis of 133 fossil and living lepidosaurs scored for 1318 morphological characters suggests that Eichstaettisaurus gouldi and Bavarisaurus macrodactylus are sister species.

“Eichstaettisaurus schroederi and the cololizard form a polytomy with that clade in an holophyletic Eichstaettisauridae with the unambiguous synapomorphies of paired premaxillae, angulated jugals, and presence of a hook-like postglenoid humeral process. Eichstaettisaurus gouldi and Bavarisaurus macrodactylus are united by the shared presence of a straight frontoparietal suture. The cololizard differs from Bavarisaurus macrodactylus in possessing an anteriorly arching (rather than a W-shaped) frontoparietal suture, a fused (unpaired) parietal, and anteroposteriorly-oriented parietal supratemporal processes. The cololizard differs from Eichstaettisaurus schroederi in possessing a weakly inclined maxillary nasal process, an anteroposteriorly elongate (rather than tall)prefrontal, a longer prefrontal orbital process, absence of cristae cranii, and an anteriorly arched (rather than transverse) frontoparietal suture. The cololizard will soon be named as a type specimen within the type specimen for Compsognathus, and further expands known Jurassic Bavarian lizard diversity.”

Figure 2. Click to enlarge. Cleaned up reconstruction of the former Bavarisaurus (cololizard at present). Gray areas added based on sister taxa. This is a tritosaur.  Note the large naris bounded ventrally by the maxilla. The ventral pelvis is shallower. I don't understand the pterygoid morphology anteriorly. The upper and lower teeth don't match. That's a red flag, but it is the only data available.

Figure 2. Click to enlarge. Cleaned up reconstruction of the former Bavarisaurus (cololizard at present). Gray areas added based on sister taxa. This is a tritosaur.  Note the large naris bounded ventrally by the maxilla. The ventral pelvis is shallower. I don’t understand the pterygoid morphology anteriorly. The upper and lower teeth don’t match. That’s a red flag, but it is the only data available.

Homoeosaurus? macrodactylus holotype
The holotype of Bavarisaurus/Homoeosaurus? macrodactylus (Wagner 1852, Fig. 3) is indeed different than the ingested lizard (Fig. 1, Nopcsa 1903, Hoffstetter 1964).

Figure 3. Homoesaurus/Bavarisaurus? macrodactylus actually nests with Huehuecuetzpalli, so the lizard inside Compsognathus is indeed different.

Figure 3. Homoesaurus/Bavarisaurus? macrodactylus actually nests with Huehuecuetzpalli, so the lizard inside Compsognathus is indeed different.

Figure 3. Eichstaettisaurus schroederi.

Figure 3. Eichstaettisaurus schroederi is considered by Conrad to be a sister to the ingested lizard, but it doesn’t appear to share many traits as far as I can tell, and phylogenetic analysis confirms this. Eichstaettisaurus actually nests basal to Adriosaurus and snakes.

No one should know lizards better than Conrad
whose 2008 paper tested 222 fossil and extant taxa with 363 character traits. Unfortunately that phylogeny: (1) failed to find a third lepidosaur clade; (2) nested snakes with amphisbaenians (legless traits must have swamped out other traits); (3) failed to find the diphyletic origin of snakes, but nested the highly derived Leptotyphlops at the base; (4) nested the pre-snake Adriosaurus with mosasaurs; and (5) failed to recover the Eichstaettisaurus / Ardeosaurus link with Adriosaurus and snakes. Otherwise, the tree looked pretty good.

The large reptile tree nests the ingested lizard in the middle of the Tritosauria. The tree nests the holotype of Homoeosaurus macrodactylus with Huehuecuetzpalli, not with Homoeosaurus solnhofensis. The tree nests Eichstaettisaurus with Ardeosaurus close to Adriosaurus, the ancestor of terrestrial snakes.

References
Conrad J 2008. Phylogeny and systematics of Squamata (Reptilia) based on morphology. Bulletin of the American Museum of Natural History 310:1-182.
Conrad J 2014. The lizard (Squamata) in Compsognathus (Theropoda) is a new species, not Bavarisaururus. Journal of Vertebrate Paleontology abstracts.
Hoffstetter R 1964. Les Sauria du Jurassique supérieur et specialement les Gekkota de Baviére et de Mandchourie. Senckenberger Biologische 45, 281–324.
Nopcsa F 1903. Neues ueber Compsognathus. Neues Jahrbuch fur Mineralogie, Geologie und Palaeontologie 16: 476-494.
Wagner A 1852. Neu-aufgefundene Saurier, Uberreste aus dem lithographischen Schiefern und dem obern Jurakalke: Abhandlungen der Bayerischen Akademieder Wissenschaften Mathematisch-naturwissenschafliche Kl, 3(6): 661-710.

 

Scandensia is a key taxon at the base of the Squamata

Changes made December 04, 2014 to renest Scandensia basal to the Squamates, not the Lepidosauria.

From the Early Cretaceous of Spain, 
Scandensia has been described as “an unusual lizard” and “enigmatic.”

From Bolet and Evans 2011
“The original description of Scandensia (Evans and Barbadillo 1998) established that it was a squamate (e.g. jaw and tooth morphology, emarginated scapulocoracoid fenestrate clavicle, absence of gastralia) and this is confirmed by the new specimen (e.g. co-ossification of the pelvic bones, pubic morphology). The first phylogenetic analysis (Evans and Barbadillo 1998), using PAUP and a modified version of the Estes et al. (1988) matrix, put Scandensia in a basal position on the squamate stem.”

Figure 1. Scandensia a basal lepidosaur

Figure 1. Scandensia a basalmost squamate.

The present analysis confirms that nesting
Here Scandensia nests at the base of the Squamata, which means it was relic from the Early Permian living in the Early Cretaceous. Tendril-like fingers and toes mark it as arboreal.

The misnamed “Langobardisaurus” rossii, MFSN 19235, is the current larger outgroup taxon.

Figure 2. Langobardisaurus(?) rossii (MFSN 19235) reconstructed. Here it nests between basal sphenodontids and basal tritosaurs + squamates.

Figure 2. Langobardisaurus(?) rossii (MFSN 19235) reconstructed. Here it nests between basal sphenodontids and basal tritosaurs + squamates. Probably not a climber, but a digger.

There’s a whole other world of lepidosaurs being discovered that don’t fit into the established clades like the Sphenodontia and the Squamata. The Tritosauria are among them, but other clades, like the one that includes Scandensia and MFSN 19235, are out there and more should be expected.

References
Evans SE and Barbadillo LJ 1998. An unusual lizard (Reptilia: Squamata) from the Early Cretaceous of Las Hoyas, Spain. Zoological Journal of the Linnean Society 124:235-265.
Bolet A and Evans SE 2011. New material on the enigmatic Scandensia, an Early Cretaceous lizard from the Iberian Peninsula. Special Papers in Palaeontology 86:99-108.

Pulling Bavarisaurus out of the belly of Compsognathus

Figure 1. Click to enlarge. The little Jurassic lizard Bavariasaurus was found inside the belly of the little Jurassic dinosaur, Compsognathus. But it is not the same genus as the holotype.

Figure 1. The little Jurassic lizard Bavariasaurus was found inside the belly of the little Jurassic dinosaur, Compsognathus. Illustration by Franz Nopcsa 1903.

As everyone knows, one Jurassic lizard, Bavarisaurus macrodactylus (Figs. 1-4, = Homoesaurus macrodactylus Wagner 1852, Hoffstetter 1964; length: ~20cm, (Lower Tithonian), Solnhofen), was found inside the belly of a small Jurassic dinosaur, Compsognathus (BSPHM AS-1-563). All curled up like the good meal it was, Bavarisaurus has been added to various lepidosaur phylogenetic analyses, but, to my knowledge, it has not been reconstructed in the literature. However, Tracy Ford did a good job here.

Figure 2. Like Michelangelo removing the excess marble, I removed every trace of Compsognathus, leaving nothing but Bavarisaurus in step 1.

Figure 2. Like Michelangelo removing the excess marble, I removed every trace of Compsognathus, leaving nothing but Bavarisaurus in step 1.

Not sure how much good this will do, but I took all the bones I could see and segregated from the dinosaur bones (Fig. 2), then rearranged them as well as I could (Fig. 3). Seems like Bavarisaurus had quite a long tail when it is all stretched out! Looking at the maxilla and mandible you’ll notice the teeth don’t match. Small triangle-shaped teeth are on the dentary, but posteriorly-oriented narrow, sharp teeth appear on the maxilla. The presumes that I have the maxilla correctly oriented.

Figure 3. Click to enlarge. Moving the bones of Bavarisaurus into a reasonable reconstruction is step 2.

Figure 3. Click to enlarge. Moving the bones of Bavarisaurus into a reasonable reconstruction is step 2.

The next step was to tentatively nest the elements phylogenetically, then clean them up in a better presentation in dorsal and lateral views (Fig. 4). A final scoring of elements nests Bavarisaurus more securely.

Figure 2. Click to enlarge. Cleaned up reconstruction of the former Bavarisaurus (cololizard at present). Gray areas added based on sister taxa. This is a tritosaur.  Note the large naris bounded ventrally by the maxilla. The ventral pelvis is shallower. I don't understand the pterygoid morphology anteriorly. The upper and lower teeth don't match. That's a red flag, but it is the only data available.

Figure 2. Click to enlarge. Cleaned up reconstruction of the former Bavarisaurus (cololizard at present). Gray areas added based on sister taxa. This is a tritosaur.  Note the large naris bounded ventrally by the maxilla. The ventral pelvis is shallower. I don’t understand the pterygoid morphology anteriorly. The upper and lower teeth don’t match. That’s a red flag, but it is the only data available.

Bavarisaurus is another tritosaur. 
And that’s why it nests uncertainly at the base of the Squamata in prior analyses that did not include any or many other tritosaurs — because it doesn’t nest in the Squamata. In the large reptile tree Bavarisaurus nests between Meyasaurus and the Dahugou lizard + Lacertulus, not far removed from Dalinghosaurus, which it resembles by convergence.

So based on the presence of Lacertulus in the Late Permian, something very much like Bavarisaurus originated in the Permian and continued to the Late Jurassic where we find the first and last of this genus inside the ribcage of Compsognathus.

References
Evans SE, Raia P and Barbera C 2004. New lizards and rhynchocephalians from the Lower Cretaceous of southern. Italy. Acta Palaeontologica Polonica 49:393–408.
Hoffstetter R 1964. Les Sauria du Jurassique supérieur et specialement les Gekkota de Baviére et de Mandchourie. Senckenberger Biologische 45, 281–324.
Nopcsa F 1903. Neues ueber Compsognathus. Neues Jahrbuch fur Mineralogie, Geologie und Palaeontologie 16: 476-494.
Wagner A 1852. Neu-aufgefundene Saurier, Uberreste aus dem lithographischen Schiefern und dem obern Jurakalke: Abhandlungen der Bayerischen Akademieder Wissenschaften Mathematisch-naturwissenschafliche Kl, 3(6): 661-710.