basal Ornithischia or Ornithischia incertae sedis

Ornithischian predentary no longer a neomorphy

Ferigolo, J. & Langer, M. (2005): the origin of the ornithischian predentary bone. Sixty-fifth annual meeting, Society of Vertebrate Paleontology, Mesa, Arizona. – J. Vert. Pal. 25 (3), 56.

Among dinosaurs (and all archosaurs except Silesaurus?), ornithischians are the only wearing a predentary. Thus it has been considered a neomorphy. As it had arisen from a stage of two distinct bones, these similarity to other vertebrates, e.g. some fishes or amphibians, would point it out to a homologous structure of Vertebrata in common. The charakter is then  a synapomorphy among dinosaurs. New material from the Caturrita Formation, Late Triassic of Brazil, is referred to a basal ornithischian. Its predentaries are distinct from each other and from dentaries, being clearly an ancient state of ornithischian beak bones. As seen in more derived ornithischians, the predentary is fused to a single element, not able to be referred to a double boned complex. The predertary/-ies of the new basal taxon as well as of each ornithischian are toothless.

Global clade of Ornithischia reviewed

Butler, R. (2005): The phylogeny and evolutionary history of the ornithischian dinosaurs. Sixty-fifth annual meeting, Society of Vertebrate Paleontology, Mesa, Arizona. – J. Vert. Pal. 25 (3), 41.

Personal comment: I have no trust in such analysing methods. They are helpful for discussing models, but never will substitute man-made judgements. Computers cannot diversify uncritical, unessential features versus convergences.

A new analysis of all valid Ornithischians has been made with the help of cladistic programs. The clade is similar to that of former work, but several taxa differ from their common position. Some results are: a.) In concordance with their geological age, Heterodontosauridae may represent the most primitive stage in ornithischian evolution. They form the sister group of Genasauria. b.) Hypsilophodonts are paraphyletic. “Yandusaurus” multidens and Agilisaurus form sister-taxa to the Cerapoda. c.) The split between Ornithopoda and Marginocephalia dates Mid- to Late Jurassic. Marginocephalians have to be expected in deposits much older than yet known.

Lesothosaurus diagnosticus maybe slept during dry months.
Agilisaurus vs. Bienotheroides (mammaloid; Chinese mid Jurassic).

Heterodontosaurids not to be found in China

Barrett, P. & Xu, X. (2005): A reassessment of Dianchungosaurus lufengensis Yang, 1982a, an enigmatic reptile from the lower Lufeng Formation (Lower Jurassic) of Yunnan Province, People’s republic of China. – J. Paleont. 79 (5), 981-986.

The fragmentary fossil material on which the initial description of Dianchungosaurus was based on, has recently been reviewed. The only report of any heterodontosaurid from Asia is invalid now for that group generally known from the Triassic-Jurassic boundery of South Africa and America. The researchers poited out that the remains are chimeric, built of the premaxillary of a mesoeucrocodylian and skull bones of a prosauropod dinosaur. The latter are common among Lufeng biota. 

Ferganocephale. Taxonomy unclear, stegosaurid or pachycephalosaurid.

Pachycephalosaurian origins

   `-or maybe both?!

First evidence on polar Pachcephalosaurians

Gangloff, R., Fiorillo, A. & Norton, D. (2005): The first pahcycephalosaurine (Dinosauria) from the paleo-arctic of Alaska and its paleogeographic implications. – J. Paleont. 79 (5), 997-1001.

The Prince Creek Formation has beared many dinosaur fossils near the Colville River, Brooks Range, Alaska. The fauna includes tyrannosaurids, troodontids, ornithomimids, dromaeosaurids, hadrosaurids, “hypsilophodontids” and ceratopsids. Now, this assemblage is extended through the discovery of a node-wearing squamosal of a pachycephalosaurine. Its ornamentaion pattern supports a new genus of fully-domed Pachycephalosauria.

Emausaurus ernsti, skull modified after Haubold 1990.
NEW Two stegosaurs mating. That behaviour would have been both essential as difficult, espacially if they really had the prominent shoulder spikes, but that's not clear. And if they had success, a baby dinosaur was hatched (skeleton and baby scene from the Dino-Calendar 2006). A partial skeleton of a 2m-juvenile from the Dinosaur National Monument is claimed to be a Stegosaurus sp. - after Carpenter et al. 1994.
NEW Liaoningosaurus, a primitive ankylosaur of uncertain phylogenetic position, known from a single skeleton with skin. Total length ca. 0.4 m. (from the Dino-Calendar 2006)

Gargoyleosaurus redescribed

Kilbourne, B. & Carpenter, K. (2005): redescription of Gargoyleosaurus parkpinorum, a polacanthid ankylosaur from the Upper Jurassic of Albany County, Wyoming. – N. Jb. Geol. Paläont. Abh. 237, 111-160.

The Jurassic polacanthid Gargoyleosaurus parkpinorum (Morrison Fm, Wyoming) has finally been described in detail. After Carpenter et al. had named the 3-3.5 m long animal in 1998, it has been reconstructed and mounted. It preserved an in situ bony armor, a noticeable elongated skull and eight alveols in its premaxillary. Thus it is a rather primitive Ankylosaurian, giving more confusion about the polacnthid phylogenetic position.

NEW Pinacosaurus grangeri (juveniles; pack scene used for title of the Dino-Calendar 2006))
Pinacosaurus mephistocephalus (skeleton mixed postcranial with P. grangeri)
                                         basal Ornithopoda: Hypsilophodontidae, Dryosauridae
Leaellynasaura amicagraphica from the Cretaceous of Australia has been claimed to be a homoiotherm animal adapted to stand the polar night. Many painters have given hairy skins to their ornithischians (e.g. Greg Paul), but little evidence is known about that. This is my first try for a step-by-step reconstruction of the Australien hypsilophodontids (Qantassaurus, Leaellynasaura, Fulgurotherium, Atlascopcosaurus).
Bugenasaurus infernails, portrait with fleshy ears.
Thescelosaurus + Elmisaurus
NEW Dryosaurus altus (right: scene with climbing chicks + a pterosaur Phamphorhynchus, taken for the Dino-Calendar 2006)

Anabisetia, a Cenomanian dryosauromorph from Argentina, with unknown birds.

                                                Ankylopollexia: Iguanodontidae, Hadrosauridae
historical reconstructions of Iguanodon: Above the modern version, maily introduced by Norman and Sibbick; below the first sketch by Mantell, Hawkins' sculpture for the Crystal Palace Park, and in fully erected stance by Dollo.
A new iguanodontian: The 1st dinosaur from Czech Republic. Enter
a hurted Prosaurolophus, best friend of some little scaveners

Age determination in dinosaurs not as good as estimated        

Baziak, B. (2005): Interspecific similarities in lines of arrested growth in tibiae of Maiasaura beeblesorum. Sixty-fifth annual meeting, Society of Vertebrate Paleontology, Mesa, Arizona. – J. Vert. Pal. 25 (3), 34.

Long bones of Maiasaura from the Campanian Two Medicine Formation of Montana have been used to study histology. Lines of arrested growth (LAG) were commonly thought to be a certain indicator for individual ages, showing different assimilation rates. Its a good tool for relative comparisons, but the problem is that LAG numbers vary between several bones in same indivuduals and even longitudinally within single long bones.


New Mexican lambeosaurine

Gates, T., Sampson, S., Eberth, D, Hernandez Rivera, R., Aguillo, M. & Delga-do-Jesus, C. (2005): A new genus and species of lambeosaurine Hadrosaur (Dinosauria: Ornithopoda) from the late Campanian Cerro del Pueblo Formation, Coahuila, Mexico. Sixty-fifth annual meeting, Society of Vertebrate Paleontology, Mesa, Arizona. – J. Vert. Pal. 25 (3), 62.

Hadrosaurs are the most common in the dinosaur fauna of the Cerro del Pueblo Formation, Coahuila, Mexico (late Campanian). For over 80 years, no crested hadrosaur genus has been described from North America, now such a lambeosaurine comes out of this Formation. A marine-influenced calcareous mudstone beared a new genus, maybe the most basal American Lambeosaurine. Its crest is not fully developed, and the specimen clearly differs from all known relatives. From the life time of the new hadrosaur, two other taxa – Parasaurolophus tubicen from New Mexico and Hypacrosaurus altispinus from Alberta – are known, supporting a hypothesis of hadrosaur provincialism.

Corythosaurus "bicristatus" casuarius
Lambeosaurus laticaudus, the giant species from California, twice the length of Corythosaurus.
NEW In 2000, Sullivan and Bennett desdribed a partial skull of a juvenil Parasaurolophus from New Mexico. I have combined the single bone photos from their paper to a complete reconstruction. Skull and family scene from the Dino-Calendar 2006.

Ontogeny of Parasaurolophus crest

Evans, D. & Reisz, R. (2005): The first insights into the early crest ontogeny of Parasaurolophus (Ornithischia: Hadrosauridae). Sixty-fifth annual meeting, Society of Vertebrate Paleontology, Mesa, Arizona. – J. Vert. Pal. 25 (3), 54.

From most lambeosaurine taxa of North America, ontogenetic growth series of the skull are known. Only for Parasaurolophus, juveniles are not reported as often as of its relatives. The authors have reviewed the diagnosis of a braincase from the Judith River Formation, Alberta, originally referred to Lambeosaurus. Some charakters pointing out a frontal-nasal-articulation at a crest’s base are typical for Parasaurolophus. Thus skull roof is noticeable different between this genus and the so called corythosaurs, and the development of crest (or of non-corythosaurian anatomy) happens earlier than in other lambeosaurines’ ontogeny. This is the second specimen of any juvenile Parasaurolophus skull; the first, bigger one is known from New Mexico (see above).

Psittacosaurus, one of the best known dinosaurs. There are several species, including a rather primitive form (Hongshanosaurus is even more primitive). We know scutes and bristles of its total skin. And we have an idea on its behaviour from a nest-like sediment structure covered with a (?)mother skeleton plus 34 chicks. Bone fragments from another specimen's gastric area indicates omnivory, if it is not swallowed as a gastrolith.
 right - family scene from the Dino-Calendar 2006
Psittacosauridae, skull table including P. sibiricus, a species with unusual anatomy, and Honghshanosaurus (A juvenile + B adult)
NEW Protoceratops, left: P. andrewsi, a pair of adults;

right: P. hellenikorhinus, mother with chicks (from the Dino-Calendar 2006)

Bagaceratops, reconstructed as a pig-like animal with short legs. I have used this body shape for me stamp motive (Afghanistan).
Prenoceratops pieganensis, a leptoceratopsid ceratopsian, described in 2004. The paper depicts separate skull bones only. But there is postcranial material, too. This will be presented later. Meanwhile I've chosen Russell's Leptoceratops for postcranials. B. Chinnery (MOR), the worker who named Prenoceratops, considers this to be okay.
Two Achelousaurus bulls fighting. Their noise scares some little troodons.
Pachyrhinosaurid youngster (left) and Pachyrhinosaurus head shield, dorsal view, title of 2005 dinosaur calendar (right).

New Data on juvenile Triceratops

Horner, J. & Goodwin, M. (2005): A new Triceratops cranial growth series. Sixty-fifth annual meeting, Society of Vertebrate Paleontology, Mesa, Arizona. – J. Vert. Pal. 25 (3), 71.

Cranial anatomy and ontogeny is studied in growth series. Many mave been produced for dinosaurs, especially for hadrosaurs and basal Ceratopsia. Now, ten Triceratops skulls from the Hell Creek Formation, Montana, are arranged to such a series, refering specimens from UCMP and MOR collection. The skull are between 30 cm and 205 cm in length. The smaller specimens posessed 17 scallops on the frill’s margin, whereas ossificated epoccipitals occure in skulls of 50 cm and longer. Their ornamentation counts 17 to 19 epoccipitals. Young Tricertatops had a basal skull lenght (without frill) of 45%, increasing up to 70% in adults. To reversion of recurving postorbital horns to procurved horns is seen in late subadults, whereas young individuals had prominent horns from their early ontogenesis on, too. Profile and shape of the nasal horn (fusing the distinct nasal bones) vary. The presence of horns and ornamentation in every age class supports an interpretation of display structures, including sexual dimorphism.

Triceratops (a baby skull has been found in Montana, with a length of 38 cm, depictured by Horner 2001)

New specimen from Naashoibito is a Chasmosaurine

Farke, A. & Williamson, T. (2005): A chasmosaurine Ceratopsid parietal from the naashoibito member, Ojo Alamo Formation of New Mexico, with implications for ceratopsid systematics and biogeography. Sixty-fifth annual meeting, Society of Vertebrate Paleontology, Mesa, Arizona. – J. Vert. Pal. 25 (3), 55.

One of the lesser fragmentary fossils from the Ojo Alamo Formation, Maastrichian of New Mexico, has recently been reported from the Naashoibito member. The incomplete parietal articulated with an epoccipital (NMMNH P-44477) a from a chasmosaurine Ceratopsid. One charakter, a single midline epoccipital on the caudal margin of the parietal, is known only from Triceratops, not from Torosaurus latus, whereas the state is unknown in Torosaurus utahensis. The feature is not visible on single parietal, as CT and digital reconstruction of that element bone have shown. Thus, the many isolated parietals from the Naashoibito member or elsewhere are not able to be reffered to a distinct genus. Thus it is no longer an autapomorphy of Triceratops. As the Naashiobito thin frilled Ceratopsians are not Torosaurus latus, new evidence for a distinct southern fauna in North America is found.

Chasmosaurus irvinensis