Perhaps Tulerpeton had only 5 fingers (and five toes)

Let’s get right to it.
Tulerpeton (Fig. 1) was originally described with six fingers. If not six fingers, where did that sixth finger come from?

The other hand.
Specifically, the tip of finger 4 from the left hand (Fig. 1) provides a suitable match.  The left hand is otherwise buried in the matrix beneath the well-exposed right hand.

Figure 1. Tulerpeton manus with digit 6 re-identified as the top of digit 4 from the other hand.

Figure 1. Tulerpeton manus with digit 6 re-identified as the top of digit 4 from the other hand. The drawing at left is the in situ presentation. The diagram at right is the traditional six-finger interpretation. The manus in the middle represents the new hypothesis of digit identity.

Tulerpeton sisters in the LRT
don’t have a digit 6. So, maybe the original description was a mistake.

Likewise, the pes of Tulerpeton
was also originally described with six digits (Fig. 2). However, a new interpretation first discussed here indicated only five toes were present. That sixth digit was created to fill a perceived space produced by broken and displaced phalanges.

Figure 1. Tulerpeton pes reconstruction options using published images of the in situ fossil.

Figure 2. Tulerpeton pes reconstruction options using published images of the in situ fossil.

References
Coates MI and Ruta M 2001 2002. Fins to limbs: What the fossils say. Evolution & Development 4(5): 390–401.
Lebedev OA 1984. The first find of a Devonian tetrapod in USSR. Doklady Akad. Navk. SSSR. 278: 1407–1413.
Lebedev OA and Clack JA 1993. Upper Devonian tetrapods from Andreyeva, Tula Region, Russia. Paleontology36: 721-734.
Lebedev OA and Coates MI 1995. postcranial skeleton of the Devonian tetrapod Tulerpeton curtum Lebedev. Zoological Journal of the Linnean Society. 114 (3): 307–348.
Mondéjar-Fernandez J, Clément G and Sanchez S 2014. New insights into the scales of the Devonian tetrapods Tulerpeton curtum Lebedeve, 1984. Journal of Vertebrate Paleontology 34:1454-1459.

wiki/Tulerpeton

 

New Evolution of Humans Video on YouTube

The origin of mammals from cynodonts is universally accepted.
The origin of humans from primates is universally accepted among paleontologists, not among religious conservatives. Perhaps this short video can help fact check a few misconceptions.

Figure 1. Human evolution video on YouTube. Cllick to view.

Figure 1. Human evolution video on YouTube. Cllick to view.

Here you’ll see the origin of humans,
and all their many body parts, in a new light. We start with fishy tetrapods, just hitting the beachheads 365 million years ago (mya). By 340 mya the first reptiles were already diversifying. Our lineage goes on from there in a stepwise progression with novel traits appearing with each successive taxon every few million years in the fossil record.

The record is becoming more and more complete.
Using the closest known sister taxa to the actual lineage we can document a gradual accumulation of human traits, both bones and soft tissues, as well as likely behaviors based on phylogenetic bracketing. Here the human lineage runs through the reptilomorphs and seymouriamorphs, the basal reptiles, the synapsids, the therapsids, the cynodonts, the mammals, primates, anthropoids and hominids, only some of which ultimately evolved to become human.

Feel free to pause the video
at any point if scenes change before you finish reading a frame.

Look for other YouTube videos
that document the origin of pterosaurs, dinosaurs and turtles in a similar fashion.

More details and reference materials
can be found at ReptileEvolution.com

Want more?
For the story of human evolution going back through raw chemicals, cells, worms and fish (along with all of the above taxa), read “From the Beginning, the Story of Human Evolution” by David Peters (Little Brown, 1991), a copy of which can be found as a pdf online at www.davidpetersstudio.com/books.htm

2013: The Year in Review at PterosaurHeresies

Thank you for making this a memorable year.

WordPress is kind enough to supply year end stats. Here they are:

Most popular post this year: “Eosinopteryx Feathers, but no Flapping.”

These are the posts that got the most views in 2013.

Visitors from 162 countries. Most came from The United States. Germany & The United Kingdom were not far behind.

Not sure what makes a particular post popular. Heck, it could be the weather. But if there’s anything you want me to write about, please, let me know.

There are times when I’m stacked up with two weeks of posts ready to upload. Now is not one of those times as I’m busy working on a paper or two. And, of course, the incoming news stream seems to be drying up as of late.

I’m encouraged by the increasing use of traced photographs in academic publications. This ensures 1:1 accuracy. Color overlays help readers see the extent of bones much better than unordered areas identified by arrows. I’m still hopeful that paleontologists will expand the gamut of their inclusion sets. Maybe we’ll start seeing that in 2014.

I’m often plagued by the thought that I’m about to run out of topics. As I near 1000 blog posts, that reality is no doubt coming closer. Inspiration drives this blog, but it’s a fickle emotion, here today, gone tomorrow.

Some highlights from 2013 include:

January

February

March

April

May

June

July

August

September

October

November

December

It’s been a great year. Thank you for your comments, especially those that improve the data that builds this blog.

Happy 2014!

Minor changes to the large reptile tree

Adding a few taxa to the large reptile tree generally causes a reassessment of past scorings that stand out as autapomorphies. Some of these represent earlier mistakes. When the mistakes are corrected the tree can shift the nesting of taxa. Some taxa are only one or two steps away from a minor shift anyway, especially the incomplete taxa. So this can happen. No major tree topologies have changed, however.

Turfanosuchus
Previously nested outside of the Archosauria, Turfanosuchus now nests at the base of the Dinosauriformes along with the PVL 4597 specimen attributed to Gracilisuchus, Trialestes and Herrerasaurus, which drops out of the Theropoda.

Batrachotomus and Saurosuchus
Now nest together. No biggie.

Saurosphargidae
The nesting of the referred specimen of Brazilosaurus at the base of the Thalattosauria somehow shifted Largocephalosaurus and Sinosaurosphargis back to the base of the Sauropterygia (placodonts + plesiosaurs). These two are so different from their sisters, yet this nesting is only held in place by a few steps. And it’s still entirely possible that the dermal armors of saurosphargids and placodonts were derived independently.

Protodiapsids
The list of protodiapsids have arranged themselves into three distinct clades, shortening the phylogenetic distance between the basal synapsid Archaeothyris and basal diapsids like Tangasaurus (Enaliosauria) and Thadeosaurus (Younginids and Archosauriformes).

Cephalerpeton
The basal reptile Cephalerpeton now nests basal to only the new Lepidosauromorpha. This makes the Reptilia truly diphyletic following the tiny Gephyrostegus specimen. Cephalerpeton shares more traits with those early captorhinomorph herbivores than the more insectivorous and lizardy Brouffia, at the base of the new Archosauromorpha.

Milleretta RC14 and Bolosaurids
Bolosaurids now nest separate from the caseids and the higher Lepidosauromorpha.

Odontochelys, still not a turtle
Odontochelys nests outside of the clade that produced Proganochelys, so developed its turtle-like traits by convergence based on the current list of characters and taxa. Another putative turtle ancestor, Eunotosaurus nests closer to caseids.

Tritosaurs up to 18+ taxa
Not bad for a totally new clade… Not counting all the pterosaurs, drepanosaurs, macrocnemids, etc. the Tritosauria now number 18 in the large reptile tree. Let’s put some more of these former oddballs and former enigmas into lepidosaur trees to confirm or deny this topology.

It just takes a little effort and a sense of wonder. And take off those blinders!

Reptile Phylogram Updated

As promised, updates arrive, but not always promptly.

Here is an updated phylogram of the large reptile tree placed against a time scale. Due to the large number of taxa (340+) it is quite impossible to read this unless you download the PDF file. Then there’s no limit to its magnification.

A phylogram differs from a cladogram in showing the amount of change between taxa by the length of the horizontal bars. Longer bars indicate greater morphological change.

Figure 1. The new phlogram of the Reptilia and its outgroups. Click for pdf file. Even at this scale the diphyletic nature of the Reptilia is readily apparent, as is the great flowering of reptiles in the Permian and Triassic.

Figure 1. The new phlogram of the Reptilia and its outgroups. Click for pdf file. Even at this scale the diphyletic nature of the Reptilia is readily apparent, as is the great flowering of reptiles in the Permian and Triassic.

Some key features

1. Sometime during the Carboniferous (Mississippian + Pennsylvanian) reptiles had their origin and their original split, but not much happened or is known about them from that remote time. Reptiles remain in the minority (it was the age of Amphibians) and no great radiations occurred then.

2. The Permian was a time of great radiation for both the Archosauromorph and Lepidosauromorph lines. Among the former, synapsids paralleled proto-diapsids and early diapsids. Among the latter large diadectomorphs and pareiasaurs dominated.

3. During the PermoTriassic extinction event only a few lineages made it through.

Among the new Lepidosauromorphs the turtles (Proganochelys) and the lepidosaurs (Paliguana, Lacertulus) survived.

Among the new Archosauromorpha three main lines survived. Certain Permian synapsids evolved to become Triassic protomammals and Jurassic mammals. Dicnynodonts also made it through.

Permian enaliosaurs like Claudiosaurus and Stereosternum gave rise to a large marine radiation in the Triassic.

Permian younginoids, like Thadeosaurus and Protorosaurus, gave rise to a large terrestrial radiation in the Triassic.

4. Many of the Triassic lepidosauromorphs did not change much into the Jurassic, Cretaceous and later eras.

By contrast, most of the Triassic archosaurmorphs became extinct or evolved into other taxa during later eras.

5. There are a few chronological oddballs, like Lotosaurus, a taxon claimed to come from Early Triassic sediments, but this seems at odds with the evolution of its purported temporal contemporaries and phylogenetic sisters.

Basal Lepidosauromorpha – the story told with skulls

Sometimes it just helps
to see a bunch of taxa together to get an appreciation for the evolution of one to another to another and another. Well, here are the members of one branch of the basal reptiles, the early plant-eaters, the new Lepidosauromorpha, all taken from the large reptile tree (recently slightly revised).

Click to enlarge. These skulls are arranged phylogenetically according to the results recovered from the large reptile tree.

Figure 1. Click to enlarge. These skulls are arranged phylogenetically according to the results recovered from the large reptile tree.

Contrary to conventional thinking,
the Diadectomorpha and Chroniosuchia are nested here within the Reptilia rather than within the pre-amniotes. Contrary to conventional thinking, the Caseasauria are nested here within the Millerettidae, rather than the Synapsida. These, and other new relationships were determined by adding taxa and thereby expanding the gamut of opportunities for every taxon to nest most parsimoniously – where the changes between taxa are minimized echoing the actual tree of reptile evolution.

Central to these discussions
Romeria primus (Fig. 1 in pink) – is at the base of the millerettids that begat the bolosaurids, acleitorhinids (not related to Lanthanosuchus btw), and the caseasauria, which now has new basal members, Feeserpeton and Australothyris. Romeria primus was largely ignored in prior studies. Now, perhaps, its importance will no longer be overlooked.

Orobates (Fig. 1 in yellow) – is leading the way toward Tseajaia and Tetraceratops, Limnoscelis, Procolophon, the lineage of Diadectes, Chelonia beginning with Stephanospondylus, and not finally the Pareiasauria. Orobates, likewise needs to rise in importance and needs to be added to several more focused phylogenetic analyses.

Saurorictus, Macroleter and the lanthanosuchids, Romeriscus and Lanthosuchus.

Figure 2. Click to enlarge. Saurorictus, Macroleter and the lanthanosuchids, Romeriscus and Lanthosuchus.

I say not finally because the next clade includes Saurorictus and Nyctiphruretus (Fig. 2) and the remainder of the new Lepidosauromorpha, including lanthanosuchids (Fig. 2), owenettids and the Lepidosauriformes.

No strange bedfellows here.
All taxa demonstrated gradual transitions from one to another. With this new phylogeny and tree topology the taxa that may or may not be someday discovered can more accurately be predicted based on phylogenetic bracketing. Hopefully more discoveries will help find the sisters of Orobates that will help define the base of this new, hitherto unknown clade.

Not amphibians!
Hopefully readers will glean the important fact that limnoscelids, chroniosuchids and diadectids are not amphibians (pre-amniotes), which represents conventional thinking. No, they’re nested deep within the Reptilia, far from Gephyrostegus and its ancestors and their kin.

Eudibamus is notably absent
Because Eudibamus is not a bolosaurid. It is a basal diapsid close to Petrolacosaurus. Strong foot homologies and long suite of other traits nest it there, not with heavy, plant-eating bolosaurids.

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

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

Lessons learned about the base of the Reptilia – part 3

Earlier here and here we learned about cranial traits that distinguished pre-reptiles from reptiles and the new Lepidosauromorpha from the new Archosauromorpha. Here we’ll look at the post-crania starting with character # 130 from the large reptile tree.

130 – Cervical centra: In pre-reptiles and the new Lepidosauromorpha: height = length. In the new Archosauromorpha: height < length.

135 – Cervical ribs robust: In pre-reptiles and others. In Lepidosauromorphs (but not Cephalerpeton) they are average in size and descending.

143 – Presacrals: fewer than 26 in Gephyrostegus + the Lepidosauromorphs. 26 to 30 in Utegenia to Coelostegus but more than 30 in Brouffia + Westlothiana.

159 – T-shaped interclavicle in Lepidosauromorpha and higher Archosauromorpha (but this is not a sharp divide with the posterior stem lengthening and the shield shrinking in a series of taxa

161 – Scapula and coracoid fused: Gephyrostegus watsoni to Casineria and basal Lepidosauromorpha

165 – Scapula/scapulocoracoid robust – Lepidosauromorpha, but not Cephalerpeton

167 – Olecranon not present – Utegenia to Westlothiana, but not Lepidosauromorpha

169 – Humerus torsion > 30 degrees – Reptilia

172 – Radius + ulna greater than three times their combined width: only Cephalerpeton

173 – Manus subequal to pes – Lepidosauromorpha

174 – Metacarpals 1-3 aligned: Gephryostegus + Reptilia

175 – Longest metacarpal: 3 and 4 in pre-reptiles and basal Archosauromorpha. 4 is the longest in Lepidosauromorpha and Synapsida.

187 – Pelvic plates fused plesiomorphically. Separated in Gephyrostegus watsoniThuringothyris (basal Lepidosauromorpha?) Brouffia and Casineria. Does this mean these taxa are immature? Maybe. Or maybe this is a transition trait based on size (neotony?).

188 – Pubis orientation – Anterior in pre-reptiles and the new Archosauromorpha. Medial in the new Lepidosauromorpha.

208 – Metatarsal 1 vs. 3 – Smaller than half in Silvanerpeton, Gephyrostegus bohemicus and Paleothyris, all separated from each other, so by convergence

210 – Metatarsals 2-4 shorter than half the tibia –  new Lepidosauromorpha (but not Labidosaurus)

211 – Four is the widest metatarsal in Silvanerpeton to Captorhinidae and Archosauromorpha (but not Paleothyris and Synapsida by convergence)

215 – Metacarpals 1-3 aligned – the Reptilia, but not Synapsida

218 – Pedal 4.1 is 3x longer than wide – At least Paleothyris and Hylonomus

Merry Christmas, everyone!

Lessons learned about the base of the Reptilia – part 2

Yesterday we looked at pertinent traits 1-39 from the large reptile tree that had a character distribution and division at the base of the reptilia.  Today we’ll continue with traits 40-128, finishing up the cranial traits.

45. Frontal with posterior processes – new Archosauromorpha.

46. Intertemporal absent (actually fused to the parietal making it that much wider) – the Reptilia

48. Postparietals (and tabulars and supratemporals) angled dorsally – the Reptilia

52. 69. Squamosal descent angle is a big curve, the so-called otic notch, in pre-reptiles. It  is obtuse and not indented in reptilia (but reversed following Romeria primus).

53. Postorbital/parietal contact (remember #46 the intertemporal becomes fused to the parietal making this possible) – the Reptilia

56. Postorbital appears as a strip beneath an overlapping postfrontal in Gephyrostegus to new Lepidosauromorpha. The postorbital is otherwise triangular.

57. Frontal/nasal angle is > 45 degrees from the midline in pre-reptiles and the new Lepidosauromorpha. The angle forms a zig-zag in the new Archosauromorpha.

58. Frontal proportions are not less than 4:1 in pre-reptiles and the new Archosauromorpha. The proportions are less than 4:1 in the new Lepidosauromorpha but not Cephalerpeton.

64. The squamosal descends to mid-level, due to a posteriorly deep quadratojugal in pre-reptiles and the new Lepidosauromorpha. The squamosal extends to the ventral rim in the new Archosauromorpha.

73. The quadrate leans anteriorly in pre-reptiles and the new Archosauromorpha, but this short bone is vertical in the new Lepidosauromorpha.

79. The opisthotic rises in pre-reptiles, but is lateral with posterior fenestra in reptiles.

82. The supratemporal is long, not large in reptiles, but this reverses in the new Lepidosauromorpha after Romeria primus.

94. The suborbital fenestra is present in the new Lepidosauromorpha, but not in  Cephalerpeton.

96. The vomer teeth are small, not fang-like in the Reptilia.

102. Pterygoid extends anterior to the palatines – restricted to Brouffia and Captorhinidae, but this character is largely unknown in basal reptiles due to various taphonomic circumstances

105. Pterygoid triangular – Gephyrostegus + Reptilia

108. Premaxilla tooth number – Gephyrostegus and Brouffia have 4. Cephalerpeton to the concordians have less than 4. All others have more than 4.

109. Medial premaxillary tooth longer than the others – the new Lepidosauromorpha

113. Canine maxillary teeth – Captorhinidae + several new Lepidosauromorpha and paleothyrids in the new Archosauromorpha by convergence

119. Mandible tip – rises in Cephalerpeton to Concordia, descends in Captorhinidae and is straight in all others

128. Mandible shape ventrally – straight anteriorly then convex posteriorly in pre-reptiles to Brouffia. Straight in Westlothiana and derived taxa. Convex in the new Lepidosauromorpha.

Post-crania tomorrow.

What is Brouffia, a short series – part 3

Earlier and a day before that we looked at the problems posed by Brouffia, which two earlier workers, Brough and Brough (1967) and Carroll and Baird (1972) interpreted significantly different from each other. Both sets of workers had direct access to the fossil and presumably looked at it with binocular microscopes.  The two authors did not agree on the placement of the pineal opening, the presence or absence of intertemporal bones and several other distinctions, including the number of sacrals present. Ironically, the Brough and Brough team found an intertemporal and thus determined the specimen was pre-reptilian, but then decided there were two sacrals present, which is a reptilian trait. The Carroll and Baird team found no intertemporal, but only one sacral, a pre-reptilian trait.

Today we’ll do our best to make sense of this mess without seeing the actual fossil, or even a photo of the fossil (yes, I’m peering over the abyss). Instead we’ll pull clues from the only available data, drawings (Fig. 1) by the above two studies.

The first thing I note is that neither prior study found large palatal fangs. So that puts us over the pre-reptile/reptile divide on the reptile side. The prefrontal and postfrontal just barely did not touch. That is also a reptilian trait. The Carroll and Baird (1972) study found only one sacral, but the evidence indicated the earlier Brough and Brough (1967) study was correct in finding two sacrals. The posterior rim of the squamosal was straight, lacking an otic notch, which is another reptilian trait.

Brouffia skull reconstructed

Figure 1. The skull of Brouffia based on both Brough and Brough (1967 anterior) and Carroll and Baird (1972 posterior and overprinted here). The dorsal lacrimal and posterior jugal fade away in the reconstruction because those areas are unknown in situ. I do NOT imagine a lateral or rostral fenestra here. This is the data I used to populate the matrix.

A new reconstruction of the skull (Fig. 1) is based on the anterior data provided by Brough and Brough (1967) because the the Carroll and Baird (1972) study failed to provide data here. The posterior data is based on Carroll and Baird (1972) because it is more reptilian and we’re leaning that way due to the lack of palatal fangs, last seen in Gephyrostegus. Brough and Brough (1967) also interpreted some strange processes on the dorsal jugal that probably represent the ventral postorbital/postfrontal suture.

With the reconstruction of the skull in hand the data nested Brouffia at the most basal position in the new Archosaurmorpha branch of the large reptile tree (it’s not listed there yet, but will be before year’s end). It shares a few traits with gephyrostegids and new lepidosauromorphs that no other archosauromorph shared. I suspect that more of the palatine is hiding beneath the mandibles. The premaxilla/maxilla connection is more fragile than in any other basal reptile. Overall the skull resembles gephyrostegids and coelostegids and paleothyrids. The premaxilla dipped as in captorhinids.

I will be relaying out the appropriate pages on reptileevolution.com to make room for this key taxon at the very base of the Reptilia. This moved Cephalerpeton over to the new lepidosauromorpha, so we no longer have a single most basal reptile following Gephyrostegus. 

Still looking for photos of the specimen, if available. We’ll have one more post on this series detailing some of the traits this new taxon nesting sheds light on.

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

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

References
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. doi:10.1098/rstb.1967.0006
Carroll RL and Baird D 1972. Carboniferous Stem-Reptiles of the Family Romeriidae. Bulletin of the Museum of Comparative Zoology 143(5):321-363. biodiversitylibrary

What is Brouffia? – A short series – part 2

Yesterday we looked at two very different interpretations of the skull of Brouffia orientalis, neither of them mine. Today, here’s the post-crania in situ, part and counterpart (Fig. 1, click to enlarge it) presented by Brough and Brough (1967, one view flipped for comparisons).

Sorry we’re taking it so slow. Lots going on over here, including Christmas shopping. I’m also hoping someone out there will send a good photo of the specimen to put under DGS.

brouffia-overall-insitu800

Figure 1. Click to enlarge. Quite close to the earliest known reptile, phylogenetically, the only fossils of Brouffia are known from the Late Carboniferous. Was it a reptile? Or a close runner-up? The twin tops on the ilium are otherwise only known in pre-reptiles. If an intertemporal was present, as Brough and Brough (1967) interpret the skull, that would confirm its pre-reptile status. However if the inter temporal was gone, having fused to the parietal, as Carroll and Baird (1972) see it (above), then the phylogenetic picture is muddied.

Brough and Brough (1967) published large tracings of tiny Brouffia (which they considered a specimen of Gephyrostegus). The lack of complete ossification in the pelvis and pectoral girdle argues for an immature status in this specimen. The presence of complete ossification in the carpus argues for a mature status. Was this a small adult? Or a well-ossified (but only in certain places) juvenile? Related forms, including Cephalerpeton and Casineria did not have a coosified pectoral girdle, but others did.

No intercentra have been observed, but they may have been poorly ossified. The spaces between the centra are beveled to receive them.

Brough and Brough (1967) restore the manus with short digits. I found the hand to be longer and more asymmetric (Fig. 1), matching those of related taxa and those several nodes away.

Brough and Brough (1967) reported two sacrals, making it more reptilian. Carroll and Baird (1972) reported only one. The pelvis is unknown in Cephalerpeton, but it is more reptilian looking in the non-reptile Gephyrostegus than in Brouffia. Odd that the coracoids appear to be missing.

More later.

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

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

References
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. doi:10.1098/rstb.1967.0006
Carroll RL and Baird D 1972. Carboniferous Stem-Reptiles of the Family Romeriidae. Bulletin of the Museum of Comparative Zoology 143(5):321-363. biodiversitylibrary