New Farlow et al. (2014) Poposaurus foot paper

Farlow et al. (2014) has a new paper on the foot of the poposaurid, Poposaurus.

Figure 1. Revised skull reconstruction for the PEFO specimen. Here the anterior is considered a premaxilla. Those teeth are shaped like triangles, but they are very deeply rooted and exposed very little, which casts doubts on its hypercarnivory.

Figure 1. Poposaurus in lateral view. This dinosaur like reptile really is a dinosaur with a calcaneal heel.

From their abstract:
“The crocodile-line basal suchian Poposaurus gracilis had body proportions suggesting that it was an erect, bipedal form like many dinosaurs, prompting questions of whether its pedal proportions, and the shape of its footprint, would likewise “mimic” those of bipedal dinosaurs.

Bivariate and multivariate analyses of phalangeal and digital dimensions showed numerous instances of convergence in pedal morphology among disparate archosaurian clades.

Overall, the foot of Poposaurus is indeed more like that of bipedal dinosaurs than other archosaur groups, but is not exactly like the foot of any particular bipedal dinosaur clade.” 

Included is a comparison with other archosaur taxa, (Fig. 1). Note Terrestrisuchus has no calcaneal heel. It develops in the derived Protosuchus and also poposaurid dinosaurs, according to the large reptile tree.

Figure 1. Archosaur feet divided into traditional croc-line and bird-line clades

Figure 1. Archosaur feet divided into traditional croc-line and bird-line clades

These feet can be reordered according to the large reptile tree (Fig. 2). Though many taxa are missing that would fill in morphological gaps, the general trends are more clear here.

Figure 2. Same feet, reordered according to the large reptile tree. Only Terrestrisuchus and Protosuchus are croc-like archosaurs here. Poposaurs are basal dinosaurs.

Figure 2. Same feet, reordered according to the large reptile tree. Only Terrestrisuchus and Protosuchus are croc-like archosaurs here. Poposaurs are basal dinosaurs. Silesaurus converged with theropod dinos, as did Brachylophosaurus. Note the lack of a calcaneal heel on Terrestrisuchus, a basal croc and the development of one on Protosuchus. In similar fashion poposaurid dinosaurs developed a calcaneal heel. 

Farlow et al. noted several instances of convergence (homoplasy). Indeed homoplasy is present here, even in this small sample.

On a separate note, 
Farlow et al. was kind enough to publish a radiograph of an Alligator. I added PILs and they are quite precise in this living reptile.

Figure 3. Radiograph of Alligator foot with PILs (parallel interphalangeal lines) added. Hone and Bennett tried to argue against the presence of PILs but did not have the nerve to show a foot with more than three toes.

Figure 3. Radiograph of Alligator foot with PILs (parallel interphalangeal lines) added. Seems rather clear that such lines representing phalanges working in sets is indeed present here.

Poposaur footprints have not bee found yet. Farlow et al. (2014) reported, “With a digit III length of about 16 cm, Poposaurus gracilis may have been comparable to a small to midrange theropod in overall body size (somewhere between the makers of Anchisauripus sillimani and A. minusculus, in the terminology of Lull [1953]). The dinosaur-like pedal proportions of Poposaurus, and the similarity of its reconstructed footprint to those of some dinosauromorphs, suggest that some grallatorid forms could well have been made by Poposaurus and its close relatives. However, mistaking Poposaurus tracks for dinosaur (particularly theropod) tracks would be less likely to occur if digit I of Poposaurus routinely touched the ground. Furthermore, trackways made by Poposaurus would probably have a shorter stride/footprint length ratio than grallatorid trackways.”

Personal thought
Seems to me that on Poposaurus pedal digit one is going to impress creating a four-toed ichnite.

References
Farlow JO, Schachner ER, Sarrazin JC, Klein H and Currie PJ 2014. Pedal Proportions of Poposaurus gracilis: Convergence and Divergence in the Feet of Archosaurs. The Anatomical Record. DOI 10.1002/ar.22863

Eoraptor Re-Reconstruction

Earlier we took note of the new nesting ofEoraptor as a basal sauropodomorph in Sereno (2013), matching its nesting in the large reptile tree.

The basal phytodinosaur, Eoraptor (Figs. 1, 2), has recently been described and illustrated (Sereno et al. 2013) in its entirety.

Figure 1. Eoraptor as illustrated by Carol Abraczinskas for Sereno et al. 2013.

Figure 1. Eoraptor as illustrated by Carol Abraczinskas for Sereno et al. 2013.

The Abraczinkas illustration (Fig. 1) portrays Eoraptor as a basic theropod, despite its nesting as a basal sauropomorph. I get the impression that the torso was done essentially freehand, especially with regard to the ribs. Fingers 4 and 5 are missing in the fossil because the matrix ends there. Descendant taxa (according to the large reptile tree), like Anchisaurus, Brachiosaurus and Iguanodon have fingers 4 and 5, so Eoraptor probably had them too. They are shown in figure 2 in pink.

Figure 2. Eoraptor based on tracing illustrations in Sereno et al. 2013, including the in situ composite image.

Figure 2. Eoraptor based on tracing illustrations in Sereno et al. 2013, including the in situ composite image. Here the ribs are shorter, fingers 4 and 5 are restored, the dorsal series is less arched, the dorsal ribs are shorter, the pelvis tilts further foreword and rides lower, the crus appears more robust and neural spines are more individualized and not generalized. Ribs are not shown from posterior cervicals. I’m struck by how robust the forelimbs are.

Several other differences in the new reconstruction more accurately reflect the in situ fossil, from which it was traced. The back was straighter without the shoulder hump found in figure 1. Other slight changes are listed in the figure two caption. Even so, this early biped appears to have had a carnivorous dentition that perhaps tasted plants occasionally.

Looks like a carnivore, except…
Sereno et al. (2013) report, “The first dentary tooth in Eoraptor, in addition, is retracted from the anterior end of the dentary, which is marked by a pair of conspicuous neurovascular foramina—features that characterize plant-eating basal sauropodomorphs. These features and the short length of the lower jaws suggest that there may have been a small keratinous beak at the anterior end of the lower jaws in Eoraptor and Panphagia. We have yet to discover a carnivorous dinosaur—or for that matter a carnivorous extant lizard—that has retained teeth for predation and that has inset these teeth from the anterior end of the lower or upper jaws (Sereno, 2012). This favors Eoraptor as a herbivore.”

Manual digits 4 and 5
In Eoraptor, Herrerasaurus and other basal dinos metacarpals 4 and 5 are tiny, almost vestigial (Fig. 2) yet in their descendant, Brachiosaurus, all five metacarpals are subequal. This is odd. Fingers and metacarpals usually disappear after they become vestiges, but not this time. Evidently metacarpals 3 and 5 re-elongated to support the weight when sauropod ancestors became quadrupedal.

Figure 3. Plateosaurus hand. Note metacarpal 4 is longer than in Eoraptor, but metacarpal 5 is not.

Figure 3. Plateosaurus hand. Note metacarpal 4 is longer than in Eoraptor, but metacarpal 5 is not.

In the prosauropod, Plateosaurus (Fig. 3), the hand is quite similar to that of Eoraptor. Metacarpal 4 is  about 3/4 the size of metacarpal 3 and three phalanges are present. Metacarpal 5 remains a vestige with a single phalanx. In the basal sauropod, Shunosaurus the lateral metacarpals are more nearly alike.  Somewhere between these two taxa, we find the origin of sauropods with longer lateral digits.

Wikipedia reports, 
“Evidence against sauropod ancestry within Prosauropoda comes from the fact that prosauropods had a smaller outer toe on their hind feet than the sauropods. Many maintain that it is easier for digits to be reduced or lost during evolution than the reverse, however there is no evidence for this. The lengthening, or gaining of extra digits is common in marine reptiles, and within the theropods digit lengthening occurred at least once. Therefore, using this as evidence against ancestral prosauropods is questionable.”

References
Sereno PC, Martînez RN and Alcober OA 2013. Osteology of Eoraptor lunensis (Dinosauria, Sauropodomorpha). Society of Vertebrate Paleontology Memoir 12, 32 (Supp. to #6):83-179.

Eoraptor Confirmed as Basal Phytodinosaur

Figure 2. Eoraptor based on tracing illustrations in Sereno et al. 2013, including the in situ composite image.

Figure 1. Eoraptor based on tracing illustrations in Sereno et al. 2013, including the in situ composite image.

Abstract - We (Sereno et al. 2013) describe the basal sauropodomorph Eoraptor lunensis, based on the nearly complete holotypic skeleton and referred specimens, all of which were discovered in the Cancha de Bochas Member of the Ischigualasto Formation in northwestern Argentina. The lightly built skull has a slightly enlarged external naris and a spacious antorbital fossa with a prominent, everted dorsal margin and internal wall lacking any pneumatic extensions into surrounding bones. The tall quadrate is lapped along its anterior margin by the long, slender ventral process of the squamosal, and the lower jaw has a mid-mandibular joint between a tongue-shaped splenial process and a trough in the angular. All but the posterior-most maxillary and dentary crowns have a basal constriction, and the marginal denticles are larger and oriented more vertically than in typical theropod serrations. Rows of rudimentary palatal teeth are present on the pterygoid. Vertebral centra are hollow, although not demonstrably pneumatized,and all long bones have hollow shafts. The radius and ulna are more robust, the manus proportionately shorter, and the manual unguals less recurved than in the contemporaneous basal theropod Eodromaeus murphi. An outstanding feature of the manus of Eoraptor is the twisted shaft of the first phalanx of the pollex, which deflects medially the tip of the ungual as in basal sauropodomorphs. The long bones of the hind limb have more robust shafts than those of Eodromaeus, although in both genera the tibia remains slightly longer than the femur.

From the text - Eoraptor lunensis was placed by Sereno et al. (1993) and Sereno (1999) as the basal member of Theropoda on the basis of phylogenetic analyses that identified synapomorphies uniting Eoraptor with Herrerasaurus and other theropods.

An opposing camp emerged with the view that Eoraptor was a more basal saurischian, outside both Theropoda and Sauropodomorpha (Langer, 2004; Mart´ınez and Alcober, 2009; Brusatte et al., 2010; Langer et al., 2010).

We now regard Eoraptor as a basal sauropodomorph (Mart´ınez et al., 2011), and there are important events that led us to this new understanding. It was not until excellent remains of this dinosaur were discovered in 1996 and prepared several years later that its distinction from Eoraptor was revealed (Mart´ınez et al., 2011).

Secondly, two key discoveries came to light while working on the holotypic skeleton of Eoraptor for this monograph. We discovered that, prior to its final fossilization, slight disarticulation of digit I in the well-preserved right manus of Eoraptor (Fig. 69) had obscured a remarkable derived feature known only among large bodied basal sauropodomorph dinosaurs (Sereno, 2007b)—the medial rotation in the shaft of proximal phalanx of manual digit I that directs the tip of the ungual inward (Fig. 73D). 

We also realized that the lower jaws of Eoraptor seemed slightly short relative to the upper jaws (Figs. 16, 17) and that the anterior end of the dentaries also had vascular openings (Fig. 23) similar to those of many larger-bodied basal sauropodomorphs thought to have a small keratinous lower bill (Sereno, 2007b; Mart´ınez, 2009). By preparing between the premaxillary teeth, we were able to verify evidence from the computed tomography (CT) data that the first dentary tooth in Eoraptor, as in Panphagia (Mart´ınez and Alcober, 2009), is inset a short distance from the anterior end of the dentary.

Thirdly, the discovery of Panphagia in Ischigualasto (Martínez and Alcober, 2009) and Saturnalia in southeastern Brazil (Langer et al., 1999, 2007; Langer, 2003) highlighted postcranial features in the girdles and hind limb shared with later sauropodomorphs.

The striking similarities between Eoraptor and Panphagia and Saturnalia became apparent. 

More recently, the discovery in southeastern Brazil of wellpreserved cranial remains of Pampadromaeus (Cabreira et al., 2011) has extended the striking similarities between Eoraptor and Brazilian genera to include the skull.

We reconsider the relationships of Eoraptor and other basal dinosaurs elsewhere (Sereno and Martínez, in review). Evidence is mounting that Eoraptor and several other taxa from the Ischigualasto and Santa Maria formations (Panphagia, SaturnaliaPampadromaeus) are basal sauropodomorphs.

Based only on Sereno et al. 1993 data and whatever was online at the time
Now that several traits in Eoraptor are now published, the large reptile tree (and its limited number of characters, will be updated soon) also nested Eoraptor with Pampadromaeus and these two with Panphagia in a clade basal to the Phytodinosauria (= Sacisaurus and the poposaurs + Sauropodomorpha + Ornithischia).

This order is confirmed by Martínez et al. (2013) which found, “The analysis positions Panphagia as the basal-most sauropodomorph, followed by Eoraptor, Pampadromaeus, and a clade that includes Chromogisaurus and Saturnalia.”

So, another confirmation for a much maligned study. Nice.

References
Martínez RN, Apaldetti C and Abelin D 2013. 
Basal sauropodomorphs from the Ischigualasto Formation. Basal sauropodomorphs and the vertebrate fossil record of the Ischigualasto Formation (Late Triassic: Carnian-Norian) of Argentina. Journal of Vertebrate Paleontology Memoir 12:51-69.
Sereno PC, Forster CA, Rogers RR and Moneta AM 1993.
Primitive dinosaur skeleton form Argentina and the early evolution of the Dinosauria. Nature 361, 64-66.
Sereno PC, Martínez RN and  Alcober OA 2013. Osteology of Eoraptor lunensis (Dinosauria, Sauropodomorpha). Journal of Vertebrate Paleontology Memoir 12:83-179.

Procompsognathus – What does it look like?

The small Late Triassic archosaur Procompsognathus (~60 cm length, von Huene 1921, Fig. 1) was earlier and convincingly revealed to be a chimaera by Sereno and Wild (1992). The croc skull (Figs. 2,3) did not belong to the dino post-crania. Unfortunately no reconstruction was provided. Here (Fig. 1) is a Procompsognathus reconstruction , along with Segisaurus (~1 m length, Camp 1933) an early Jurassic dinosaur, to which it was allied.

Figure 1. Procompsognathus (below) along with Segisaurus (not to scale). We don't have the actual skull of Procompsognathus, but it was likely small, but taller than wide.

Figure 1. Procompsognathus (below) along with Segisaurus (not to scale). We don’t have the actual skull of Procompsognathus, but it was likely small, but taller than wide.

Procompsognathus post-crania
The post-cranial portion of the specimen (SMNS 12591) was considered close to Segisaurus (Fig. 1) and here nests close to it, but closer to the tiny Middle Triassic theropod, Marasuchus.  Pedal digit 1 rides a little higher on the metatarsus in Procompsognathus and Marasuchus among only a few distinguishing traits.

Distinct from Segisaurus, Procompsognathus has longer, more robust hind limbs and essentially vestigial forelimbs. It is also half as large with a much longer pubis, longer cervicals with smaller cervical ribs, a higher metatarsal 1 and shorter, more robust phalanges on pedal digit 4, which also has a very long ungual.

Figure 2. SMNS 12591a, a basal croc skull close to the ancestry of dinosaurs.

Figure 2. SMNS 12591a, a basal croc skull close to the ancestry of dinosaurs. The premaxilla is unknown and has been restored here. The palatine appears in the antorbital fenestra.

SMNS 12591a – the croc skull
A basal croc, the SMNS 12951a skull, is twice as wide as tall. The quadrate leans anteriorly. Phylogenetically the skull nests in the large reptile tree at the base of the Gracilisuchus + Scleromochlus clade and next to the Terrestrisuchus + Saltoposuchus clade. So there is a good chance that the SMNS 12951a skull was attached to gracile bipedal crocodylomorph post-crania, along the morphological lines of Procompsognathus, and not too far from the base of the Archosauria.

Figure 3. The SMNS 12591a skull reconstructed. It is twice as wide as tall, a croc feature.

Figure 3. The SMNS 12591a skull reconstructed. It is twice as wide as tall, a croc feature.

Sereno and Wild (1992) described postfrontals (blue in Fig. 2), but strangely did not illustrate them (Fig. 3). Gracilisuchus and Scleromochlus also retain postfrontals but most other crocs do not. What appears to be a post dividing the antorbital fenestra in situ is actually the displaced palatine, as described by Sereno and Wild (1992).

References
Camp C 1936. A new type of small bipedal dinosaur from the Navajo sandstone of Arizona. Univ. Calif. Publ., Bull. Dept. Geol. Sci., 24: 39-56.
Huene F von 1921.
Neue Pseudosuchier under Coelurosaurier aus dem württembergischen Keuper. Acata Zoologica 2:329-403.
Sereno P and Wild R 1992. Procompsognathus: theropod, “thecodont” or both? Journal of Vertebrate Paleontology 12(4): 435-458.

Hall Train Walking T-rex Model at the AMNH

If you haven’t seen this before, it’s as fascinating as the real thing. This walking model of T-rex, animated with rods and gears is on display at the American Museum of Natural History in NYC.

Figure 1. Click to see video. The famous walking T-rex model at the AMNH created by Hall Train and John Allen.

Figure 1. Click to see video. The famous walking T-rex model at the AMNH created by Hall Train and John Allen.

The Hall Train Studio has produced some of the most spectacular dinosaur museum displays and animation ever. I don’t want to steal too much of their thunder. Check out their website now.

Origin of Dinosaurs – Updated

Earlier we looked at the origin of dinosaurs. Here is an update.

Figure 1. The origin of dinosaurs as portrayed by the phylogenetic series of closest known sister taxa to the actual unknown undiscovered true lineage of dinosaurs. A. Youngina, B. Proterosuchus, C. Garjainia, D. Euparkeria, Vjushkovia, 1. Ticinosuchus, 2. Yarasuchus, 3. Decuriasuchus, 4. Turfanosuchus, 5. Gracilisuchus, 6. PVL 4597, 7. Trialestes, 8. Herrerasaurus, 9. Marasuchus, 10. Daemonosaurus.

Figure 1. Click to enlarge. The origin of dinosaurs as portrayed by the phylogenetic series of closest known sister taxa to the actual unknown undiscovered true lineage of dinosaurs. A. Youngina, B. Proterosuchus, C. Garjainia, D. Euparkeria, Vjushkovia, 1. Ticinosuchus, 2. Yarasuchus, 3. Decuriasuchus, 4. Turfanosuchus, 5. Gracilisuchus, 6. PVL 4597, 7. Trialestes, 8. Herrerasaurus, 9. Marasuchus, 10. Daemonosaurus.

Notably absent here are Lagerpeton, phytosaurs and pterosaurs — because they don’t belong. They were added by other studies (Brusatte et al. 2010, Nesbitt 2011) because they were following traditions and did not have a large gamut reptile study, like we do, to tell them those taxa are not closely related or in the lineage of dinosaurs.

The story here goes back to the basal archosauriform Youngina, but it could have gone back to the basal tetrapod, Ichthyostega.

A. Archosauriformes – Youngina
Derived from basal diapsids like Aphelosaurus, Thadeosaurus and basal protorosaurs (in that order), Youngina nests at the base of the Archosauriformes. This clade includes the Pararchosauriformes and Euarchosauriformes. A taller skull and a nascent antorbital fenestra without a fossa on a generalized neck and body mark Youngina.

B. Euarchosauriformes – Proterosuchus
Probably more aquatic, like a crocodile, Proterosuchus is derived from Youngina with a longer, relatively smaller skull, a longer neck and a droopy snout. The cervicals were taller. The scapula was more robust. The ilium was lower with a small anterior process. The pubis and ischium were in complete contact and oriented medially. Metatarsal 5 was reduced and hook-shaped. Pedal 1.1 was aligned with metatarsals 2 and 3.

C. Erythrosuchia – Garjainia
Possibly aquatic, like a hippopotamus, Garjainia is also derived from Youngina, largely skipping the proterosuchid stage.

D. Euparkeriamorpha – Euparkeria
So, the big question is, is Euparkeria a tiny erythrosuchid? Or just another tiny derived younginid that begat giant erythrosuchids, ornithosuchids and rauisuchids? Not sure yet. We need a few more euparkeriids. Probably terrestrial.

E. Rauisuchia – Vjushkovia
Probably terrestrial, overall Vjushkovia had the proportions of Euparkeria, only larger. It didn’t have the giant skull and short tail of erythrosuchids.  With larger size comes larger prey. From Vjushkovia we get a mixed bag of rauisuchians that includes a variety of sometimes long, necked, sometimes finbacked and long-necked, sometimes herbivorous and the slender-limbed protoarchosaurs. So this is a key taxon.

1 and 2. Ticinosuchia – Ticinosuchus and Yarasuchus
This mixed bag of taxa includes some sail-back carnivores, long-necked fish-eaters and armored plant-eaters. Ticinosuchus is basal to the armored plant-eaters, so is quite far off the basal line, better represented by Decuriasuchus (noted below), which looks more like a rauisuchid.

3. Protoarchosauria – Decuriasuchus
This mixed bag of taxa includes some long torso, short legged carnivores, like Decuriausuchus, some short-torso long-legged bipedal carnivores like Pseudhesperosuchus and a tiny likely biped, LewisuchusDecuriasuchus had an elevated neck with low neural spines, gracile forelimbs and short hindlimbs. Such a gracile pectoral girdle is also seen in the probably biped Arizonasaurus at the base of the Ticinosuchia (above).

4. Archosauria – Turfanosuchus
A single odd taxon appears here at the base of the Archosauria. Turfanosuchus looks like a smaller decuriasuchid with a smaller skull and longer neck. The torso is shorter. The tail is more gracile.

5. Crocodylomorpha – Gracilisuchus
The torso and tail continue to shrink in Gracilisuchus, nesting at the base of the Crocodylomorpha, a clade with several basal bipedal members. Here the skull is wider than tall.

6 and 7. Dinosauria – Trialestes and PVL 4597
Known from bits and scraps, Trialestes and PVL 4597 are all that we now know of the base of the Dinosauria. So there’s some mystery here! Who knows if they are bipedal or not?? Both taxa are rather mid-sized to small. PVL 4597 includes a calcaneal tuber and a dinosaurian semi-perforate pelvis. Metatarsals 3 and 4 are subequal. Trialestes retains elongated proximal carpals and had long curved teeth.

8 and 9. Theropoda - Herrerasaurus and Marasuchus
Two short-torso, long hind limb bipeds are basal dinosaur theropods. The tail is deep proximally, attenuated distally. The short torso enables the feet to be placed beneath the center of gravity, freeing the forelimbs. The neck is more gracile and probably more flexible. The dorsal vertebrae are deepest near the sacrum, not so deep both fore and aft.

10. Phytodinosauria and Ornithischia – Daemonosaurus 
Several basal dinosaurs, like Pampadromaeus and Panphagia, developed a smaller head and longer neck. Daemonosaurus continued that trend toward the Ornithischia. Neural spines are greatly reduced.

Time
Remarkable as it may seem the current chronology of the ancestry of the Dinosauria took place all within the comparatively brief Early Triassic, based on the Late Permian appearance of Youngina and the  early Middle Triassic appearance of Lotosaurus, a derived poposaurid dinosaur. Fossils of these dino ancestors, most of which come from later epochs, evidently reflect derived and late-surviving taxa, when root stocks were much more widespread and thus easier to find as fossils.

The Early Triassic appearance of Euparkeria, when it was likely widespread, may represent a Late Permian origin and diversification.

We have a Middle Triassic appearance of Ticinosuchus, itself a derived rauisuchian, but that means its more plesiomorphic ancestors, and the more direct ancestors of dinosaurs, likely appeared and diversified in the Early Triassic.

The basal dinosaurs, Herrerasaurus and Marasuchus are likewise Middle Triassic, with origins likely much earlier.

References
Brusatte SL , Benton MJ , Desojo JB and Langer MC 2010. The higher-level phylogeny of Archosauria (Tetrapoda: Diapsida), Journal of Systematic Palaeontology, 8:1, 3-47.
Nesbitt SJ 2011. The early evolution of archosaurs: relationships and the origin of major clades. Bulletin of the American Museum of Natural History 352: 292 pp.

Human and Dinosaur Tracks Together – Chimaeras and Fakes – Part 6

Creationists jumped all over the Archaeoraptor chimaera. Then they came up with this piece of carved artwork (Fig. 1, and others) they claimed was genuine. It appears on the Creation Evidence Museum website masthead. It’s a crying shame when these Christians associate themselves with acts of deception like this. They make all Christians look bad. Luckily we have scientists like Glen Kuban who fight the good fight for the rest of us.

Figure 1. The Alvis Delk print purporting to show a three-toed dinosaur intersecting with a human print. IT was "discovered" near the Paluxy River in Texas, a  Cretaceous locality.

Figure 1. Click to enlarge. The Alvis Delk print purporting to show a three-toed dinosaur intersecting with a human print. It was “discovered” near the Paluxy River in Texas, a Cretaceous locality. Both prints show evidence of being carved and neither conform to known anatomy. Note the extreme depth of the human medial toe. No pad impressions appear in the dino track, as shown in figure 2 and it lacks good morphology.

Poor Creationist artistry is the giveaway.
The human big toe is too deep and too short. The dinosaur track has no pad impressions and extends through several layers, rather than compressing them. There is no displacement of sediment from either track.

Glen Kuban has made an extensive study of the Paluxy River tracks. Here’s his take on them. The Alvis Delk Print is reported on here. Kuban reports, “a number of its features are so unrealistic that some have described it as cartoon-like. To be more specific, the hallux (big toe) of the “human” print is exceedingly deep compared to the rest of the print. The lesser toe depressions are on a plane considerably higher than the rest of the print, and jut out at an unnatural angle. The middle three toe marks are also unusually long (or overly separated from the ball area).  Also, the margin of the print lacks the “mud up-push” and other evidence of deformation usually seen on distinct prints. In the 1970′s, Glen Rose resident Wayland “Slim” Adams, explained to a group of creationists how his uncle George Adams, who carved human tracks on loose blocks and sold them to tourists during the Great Depression, usually did start with existing (but not human) depressions. George’s granddaughter recently confirmed this, as well as her grandfather’s use of acid to blur chisel marks.(Kennedy, 2008).”

Figure 2. Conmparing the alleged theropod track to a genuine theropod track. Poor Creationist artistry is the giveaway.

Figure 2. Conmparing the alleged theropod track to a genuine theropod track. Poor Creationist artistry is the giveaway. From Glen Kuban’s website, referenced below.  The A/B line intersects the claws of digits 2 and 4. Digits 1 adn 5 do not make impressions.

Then there are problems with the purported theropod track, too. Kuban reports, “a number of the Delk print’s features conflict with those of typical “Acro” tracks. A series of odd holes appears to run down the length of the middle toe and into the main body of the track. Moreover, the digits on the Delk print show little if any indications of individual digit pads which are normally detectable on real dinosaur tracks with such a distinct outline. However, it does resemble a number of other likely carvings that were made decades ago, as well as some that have come out of the Glen Rose and Stephenville area in more recent years, and which were sold to tourists.

“Unlike real tracks that show deformational lines corresponding to the print depression, the subsurface features of these loose tracks were truncated by the depressions, strongly indicating a carved origin.”

References (from Glen Kuban’s web site)
Baugh CE 2008.  Creation Museum website article: “Alvis Delk Cretaceous Footprint article here
Darrell E 2008. “Fred Flintstone waded here: Hoaxsters ready to teach creationism to Texas kids” Millard Fillmore’s Bathtub blog here.
Godfrey L 1985. “Footnotes of an Anatomist,” Creation/Evolution, Issue 15, Volume 5, Number 1 (Winter 1985)
Hurd G. Stones and Bones website blog.
Juby I  2008. “Examining the Delk Track,” August, 2008 website article.
Kennedy B  2008 (Aug 10), Fort Worth Star-Telegram“Human Footprints Along with Dinosaur Tracks?”
Ketcham RA and Carlson WD 2001. “Acquisition, optimization and interpretation of X-ray computed tomographic imagery: Applications to the geosciences.” Computers and Geosciences, 27, 381-400.
Kuban GJ 2006. On the Heels of Dinosaurs. Website article here
Kuban GJ and Wilkerson G 1989. The Burdick Print at here.
Lines D 2008. web links here
May D 2008a Rock-solid Proof? Mineral Wells Index. On line version
May D 2008b. One Step at a Time. Mineral Wells Index. On line here
Snelling AA., 1991. Website article here Originally published in: Creation 14 (1):28-33, December 1991.

Support for the Alvis Delk track is here and here.

Glen Kuban’s Paluxy track page is here and here.

Emausaurus added to the large reptile tree

Emausaurus (Haubold 1990, early Jurassic), the primitive thyreophoran ornithischian dinosaur (Fig. 1), was recently added to the taxon list and it nested with Scelidosaurus at the base of the Ornithischia without upsetting the rest of the large reptile family tree.

Figure 1. Emausaurus skull. This taxon nests with the armored basal ornithischian Scelidosaurus.

Figure 1. Emausaurus skull. This taxon nests with the armored basal ornithischian Scelidosaurus.

Emausaurus is interesting because the palpebral bones, common to all ornithischians, virtually contacted the postorbital/postfrontal creating a roof over the eyeball, leaving a virtual fenestra in the posterior remainder of the orbit. Later taxa incorporate the palpebral(s) into the skull itself.

Since Emausaurus nests with Scelidosaurus in the large reptile tree, it is difficult to say at this point which is the more primitive of the two. Additional taxa will be needed for that. It is interesting to note the longest teeth in the dentary of Emausaurus are the anterior ones, where fangs once appeared in the phylogenetic ancestor, Daemonosaurus.

The Archosauria as of today with several new taxa added since last posted.

Figure 2. The Archosauria as of today with several new taxa added since last posted. The addition of Emausaurus does not change the topology of the large reptile family tree. 

The Genasauria
Traditionally the most primitive ornithischians are Pisanosaurus and Heterodontosaurus. Both are considered sisters to all other ornithischians, collectively known as the Genasauria, a clade that traditionally splits into Thyreophora (Lesothosaurus and armored dinos) and Neornithischia (Stormbergia, Agilisaurus, Hexinlusaurus and Cerapoda (duckbills, ceratopsians and pachycelphalosaurs).

No outgroup is known yet for the Ornithischia in traditional trees.

The large reptile tree does not dive deeply into the Dinosauria, but basal forms divide into different divisions with a base on a sister to Daemonosaurus. Unfortunately, this taxon is omitted or ignored in all prior ornithischian studies. In the large reptile tree, the armored dinosaurs (Scelidosaurus and Emausaurus) split off first. Pisanosaurus is a poposaur, so is not as directly related to ornithischians as traditional paleontologists suppose.

I hope other workers will add the taxa listed above to their trees to see if this experiment can be duplicated. M. Mortimer did something similar, but oddly the theropods nested as derived rather than basal in that tree, basically upside-down from the present topology.

Similarly, Lesothosaurus, which is basal in several other trees, nests as derived in this tree, all due to the influence of new outgroups.

References
Haubold H 1990. Ein neuer Dinosaurier (Ornithischia, Thyreophora) aus dem Unteren Jura des nördlichen Mitteleuropa. Revue de Paleobiologie 9(1):149-177. [In German]

What?? No feathers on velociraptors?

Figure 1. Inside cover illustration spread for "Raptors, the Nastiest Dinosaurs" by Don Lessem, illustrated by David Peters. Don asked for a "no feathers dinosaur" so that's what he got. Don't blame the artist. I tried to persuade. Utahraptor is the big dromaeosaur here.

Figure 1. Inside cover illustration spread for “Raptors, the Nastiest Dinosaurs” by Don Lessem (1996), illustrated by yours truly, David Peters. Don asked for a “no feathers dinosaur” so that’s what he got. Don’t blame the artist. I tried to dissuade. Utahraptor is the big dromaeosaur here.

This post was inspired
by a blog and Flickerstream I ran across here and here that bemoaned the fact that my 1996 dromaeosaurids / velociraptors (Fig. 1) in “Raptors – The Nastiest Dinosaurs” did not have feathers, but did have propatagia.

Guys, I tried to add feathers, as I had done several years earlier (1989) to my own velociraptors in Gallery of Dinosaurs (Fig. 2). However, author Don Lessem insisted that no feathers appear in his book. I tried to dissuade, but was vetoed. After all, he is the author. And that was then. I’m sure Dino Don has come around to new thinking since then.

See how difficult it is to promote a new idea supported by data? Even an expert like Don Lessem balked back in 1995-6.

Figure 2. Feathered Deinonychus from A Gallery of Dinosaurs by David Peters.

Figure 2. Feathered Deinonychus from A Gallery of Dinosaurs by yours truly, David Peters. (1989). Click to enlarge.

So, there is a backstory,
as there is with other controversial aspects of my work. At present the backstory and trashed ideas are not as important as the current work. Science marches on and new data keeps coming in. So let’s stay with the current wave. If you see any other problems with my  tracings or identifications, please let me know of those issues.

References
These are kids books, not academic journals!
“A Gallery of Dinosaurs” is online here.

Jason Brougham Deinonychus skeleton model

This is excellent!

Figure 1. Deinonychus skeleton model by Jason Brougham. Click to learn more.

Figure 1. Deinonychus skeleton model by Jason Brougham. Click to learn more.

And if you haven’t become acquainted with artist/scientist, Jason Brougham, I hope you do so now. Incredible and accurate detail, dynamic pose and very birdy.

Lateral view of Deinonychus by Jason Brougham.

Figure 2. Lateral view of Deinonychus by Jason Brougham.

It’s not very often that a skeleton seems this alive.

See more at jasonbrougham.com