A Well-preserved Thallatosaur and new Evidence on the First Appearance of Angiospermy in the Mesozoic

Things have been a bit slow in Triassic-land lately and I've been too busy to be creative; however, Jeff has posted some new pics over at Paleo Errata as things start to thaw out in some places.

There is one recent paper on on Triassic marine reptiles from China:

Zhao, L.-J., Sato, T., Liu, J., Li, C., and X.-C. Wu. 2010. A new skeleton of Miodentosaurus brevis (Diapsida:Thalattosauria) with a further study of the taxon. Vertebrata Palasiatica 48:1-10.

Abstract: A new thalattosaurian skeleton from the Upper Triassic Wayao Member of the Falang Formation, Guanling area, Guizhou Province, China can be referred to Miodentosaurus brevis. The postcranial skeleton of the specimen is well-preserved and so complete that it is worthy to be described. This new specimen provides a full knowledge of the osteology of the thalattosaurian, especially the anatomy of the pectoral girdle and both the fore and hindlimbs. The presence of a few teeth restricted to the anterior ends of both the upper and lower jaws and dorsoventrally flattened ungual phalanges indicate that M. brevis is not a pure carnivore. With new information, some individual variations are recognized and the digital formula(2-3-4-5-5) of the pes can be identified as one of the diagnostic features for the thalattosaurian.


This also may be of interest, although not containing a phylogenetic analysis, the seed plant described here is proposed to be the 'sister taxon' of angiosperms and thus angiospermy evolved more than once in separate groups, or it is derived from a common ancestor in the Triassic or early Jurassic.


Wang, X., and S. Wang. 2010. Xingxueanthus: An Enigmatic Jurassic Seed Plant and Its Implications for the Origin of Angiospermy. Acta Geologica Sinica [English Edition] 84:47-55.

Abstract: The origin of angiosperms has been tantalizing botanists for centuries. Despite the efforts of palaeobotanists, most of the pre-Cretaceous angiosperms are regarded either non convincing or misdated. The applications of SEM and LM (light microscope) enable us to recognize a coalified fossil plant, Xingxueanthus sinensis gen. et sp. nov., from the Haifanggou Formation (Middle Jurassic, >160 Ma) in western Liaoning, China. Xingxueanthus is an ''inflorescence'' with more than 20 female units spirally arranged. Each female unit is situated in the axil of a bract. The female unit is composed of an ovule-container and a style-like projection at the top. There is a vertical column bearing several ovules in the ovule-container. The general morphology and the internal structure of Xingxueanthus distinguish itself from any known fossil and extant gymnosperms, and its structures are more comparable to those of angiosperms. Xingxueanthus, if taken as a gymnosperm, would represent a new class, demonstrate an evolutionarily advanced status of ovule-protection in gymnosperms never seen before, and provide new insights into the origin of angiospermy. Alternatively, if taken as an angiosperm, together with Schmeissneria, it would increase the diversity of Jurassic angiosperms, which has been underestimated for a long time, and suggest a much earlier origin of angiospermy than currently accepted.

New Juvenile Specimen of Lufengosaurus huenei from the Lower Jurassic of China

Sekiya, T., and Dong, Z. 2010. A New Juvenile Specimen of Lufengosaurus huenei Young, 1941(Dinosauria: Prosauropoda) from the Lower Jurassic Lower Lufeng Formation of Yunnan, Southwest China. Acta Geologica Sinica (English Version) 84:11-21.

Abstract - A skull and a series of associated cervical vertebrae (ZLJ0112)discovered from the Lower Lufeng Formation (Lower Jurassic) are determined as a juvenile specimen of Lufengosaurus huenei Young 1941 based on amended autapomorphies. Differences between ZLJ0112 and the holotype (subadult specimen) are considered as ontogenetic characteristic changes of L. huenei. Since some of these differences are present in other prosauropod dinosaurs (i.e., forms of the maxillary vascular foramen are irregular; the frontal contribution to the dorsal margin of the orbit is substantial; the frontal contribution to the supratemporal fossa is absent; the supratemporal fenestra is visible in lateral view; the supraoccipital inclined at 75 degrees; the parasphenoid rostrum lies level with the occipital condyle; the retroarticular process is short; the axial postzygapophysis project caudally beyond the end of the centrum) they may be common ontogenetic changes in prosauropod dinosaurs.

Proceedings of the First Annual Symposium on Fossil Preparation and Collections Now Available

Starting in 2008 fossil preparators and collection managers have been meeting once a year in symposia dedicated to sharing methodology and techniques regarding fossil preparation and conservation. The first meeting was held at Petrified Forest National Park and the proceedings volume from this meeting is now available on-line. The PDFs are open access, however; bound copies are also available.The 2010 meeting is being hosted by the Chicago Field Museum.

New Volume on the Early Triassic Vertebrates from Karst Deposits at Czatkowice, Poland

The most recent issue (10 papers) of Palaeontologia Polonica (Volume 65, dated 2009) is dedicated to describing the vertebrate faunal assemblage a Czatkowice Poland. The issue is open access and available at the Palaeontologia Polonica website.

MARIUSZ PASZKOWSKI
The Early Triassic karst of Czatkowice 1, southern Poland

ELIZABETH COOK and CLIVE TRUEMAN
Taphonomy and geochemistry of a vertebrate microremains assemblage from the Early Triassic karst deposits at Czatkowice 1, southern Poland

MIKHAIL A. SHISHKIN and TOMASZ SULEJ
The Early Triassic temnospondyls of the Czatkowice 1 tetrapod assemblage

SUSAN E. EVANS and MAGDALENA BORSUK−BIAŁYNICKA
The Early Triassic stem−frog Czatkobatrachus from Poland

MAGDALENA BORSUK−BIAŁYNICKA and MARIUSZ LUBKA
Procolophonids from the Early Triassic of Poland

SUSAN E. EVANS
An early kuehneosaurid reptile (Reptilia: Diapsida) from the Early Triassic of Poland

SUSAN E. EVANS and MAGDALENA BORSUK−BIAŁYNICKA
A small lepidosauromorph reptile from the Early Triassic of Poland

MAGDALENA BORSUK−BIAŁYNICKA and SUSAN E. EVANS
A long−necked archosauromorph from the Early Triassic of Poland

MAGDALENA BORSUK−BIAŁYNICKA and SUSAN E. EVANS
Cranial and mandibular osteology of the Early Triassic archosauriform Osmolskina czatkowicensis from Poland

MAGDALENA BORSUK−BIAŁYNICKA and ANDRIEJ G. SENNIKOV
Archosauriform postcranial remains from the Early Triassic karst deposits of southern Poland

Coelophysis and the Return of the Hairy Museum

Matt Celeskey (the Hairy Museum of Natural History) has returned after a blogging hiatus with the first of what offers to be an excellent series of posts on the New Mexico Museum of Natural History's Coelophysis Quarry block and what information it is yielding about the taphonomy of the site and the critters found within. It is another good example of the caliber of information you can get by careful, detailed analysis of the fossils and the surrounding sediments.

Driving Through Desmatosuchus Country

I just recently had the opportunity to drive through western Texas. This area is known many for its flat plains, the Llano Estacado or'caprock'; however, the rivers of the area remove this resistant layer exposing the Permian and Triassic strata below.

White River badlands

It is from these strata that E. C. Case of the University of Michigan collected the type specimens of many Late Triassic archosaurs including the aetosaur Desmatosuchus spurensis in 1919. This specimen came from the breaks of the White (Blanco) River, more specifically at the crossing of the old mail route between the towns of Spur and Crosbyton.

Holotype specimen of Desmatosuchus spurensis in the University of Michigan Museum of Paleontology

Almost three decades earlier E. D. Cope and his collectors had recovered the partial skeleton of another aetosaur that Cope had named Episcoposaurus haplocerus in 1892. E. haplocerus and D. spurensis remained separate taxa unofficially (several authors including Camp, 1930 had suspected they were synonymous) until 1953, when Joseph Gregory formed the new combination Desmatosuchus haplocerus (the type of Epicoposaurus, E. horridus, = Typothorax). Thus the town of Spur lost their namesake taxon as a junior synonym.


Downtown Spur, Texas

Spur is a small town of just over 1000 people east of Lubbock. Because it is surrounded by the breaks of Dockum Creek to the north and east and the White River to the west it is nesled in low hills and woods and differs from many of the other cities up on the caprock. I've visited Spur twice now, once in 2001 and just recently. Why? Because of this:


This is a mural on the side of the local history museum, which tells the story of the area. Note the prominence of Desmatosuchus in the lower right corner. Here is a close-up.


Let's just say that outdoor murals of aetosaurs are rare, and to someone who has spent over a decade researching these animals and especially this taxon visiting the area where the original specimens were collected, the town D. spurensis was named for, and this spectacular mural, is a thrill (at least for me). I'm also glad that the town of Spur has officially gotten their fossil name back. Desmatosuchus haplocerus is a nomen dubium and thus D. spurensis has been restored as a valid taxon (Parker, 2008). One day I hope to get the opportunity to explore the badlands where Case worked. It would be an ultimate thrill to relocate and document the site where this amazing fossil was collected. If anyone knows where the old mail road crossing was please let me know.

REFERENCE

Parker, W.G. (2008). Description of new material of the aetosaur Desmatosuchus spurensis (Archosauria: Suchia) from the Chinle Formation of Arizona and a revision of the genus Desmatosuchus. PaleoBios 28(1): 1-40.

New in Science - Unidirectional Airflow in the Lungs of Alligators

I have not seen this paper yet, but the implications are really cool. Thanks to Andy Farke for sharing the abstract.

Farmer, C. G., and K. Sanders. 2010. Unidirectional airflow in the lungs of alligators. Science 327(5963):338-340. DOI: 10.1126/science.1180219

Abstract: The lungs of birds move air in only one direction during both inspiration and expiration through most of the tubular gas-exchanging bronchi (parabronchi), whereas in the lungs of mammals and presumably other vertebrates, air moves tidally into and out of terminal gas-exchange structures, which are cul-de-sacs. Unidirectional flow
purportedly depends on bellowslike ventilation by air sacs and may have evolved to meet the high aerobic demands of sustained flight. Here, we show that air flows unidirectionally through parabronchi in the lungs of the American alligator, an amphibious ectotherm without air sacs, which suggests that this pattern dates back to the basal archosaurs of the Triassic and may have been present in their nondinosaur descendants (phytosaurs, aetosaurs, rauisuchians,crocodylomorphs, and pterosaurs) as well as in dinosaurs.