free paleontology articles in Lithodendron

Skip to first unread message

Adam Marsh

Jun 8, 2024, 4:41:34 PM (6 days ago) Jun 8
Dear Vert listers/Dino groupers

I am pleased to announce the inaugural volume of Petrified Forest National Park's new journal Lithodendron. This open access journal will include research topics on natural and cultural resources on, along, and nearby the Colorado Plateau.

The first volume (Spring, 2024) includes three paleontological articles:

Free pdf:

William G. Parker & Atrayee Haldar (2024)
A lateral osteoderm from Kryphioparma caerula (Pseudosuchia: Aetosauria) from the Upper Triassic (Norian) Chinle Formation of Arizona
Vol. 1, pp. 31–44

Recent collecting of fossil vertebrates in the Chinle Formation at Petrified Forest National Park (PEFO) and reinvestigation of historic collections resulted in the recognition of a new aetosaurian taxon, Kryphioparma caerula. Although distinctive, K. caerula was initially described from several fragmentary paramedian osteoderms from PEFO and the nearby Placerias Quarry, however the anatomy of the lateral osteoderms remained unknown. Here, we refer an isolated lateral osteoderm from the Placerias Quarry to K. caerula based on an ornamentation composed of large elliptical-to-rounded pits on the dorsal surface that are randomly arranged, a prominent anterior bar, a strongly obtuse angle between two partially preserved flanges, an elongate lateral eminence (spine) with a strongly embayed posterior margin, and sharp anterior ridge. This combination of anatomical features of the isolated lateral osteoderm is clearly aetosaurian and differs in significant ways from the other known aetosaurian taxa from the site. A parsimony analysis recovers K. caerula nested within the inclusive clade Typothoracinae. This lateral osteoderm demonstrates that K. caerula was a spinose aetosaur, a bauplan observed in both typothoracine and desmatosuchin aetosaurians. Thus, further highlighting observed convergence between these groups and indicating a need for a reevaluation of lateral osteoderm characters used for phylogenetic analyses.


Free pdf:

Adam D. Marsh, Christian A. Sidor, & Elliott Armour Smith (2024)
The allokotosaur (Reptilia: Archosauromorpha) assemblage from a multitaxic bonebed in the Sonsela Member (Jim Camp Wash beds, Chinle Formation) at Petrified Forest National Park, U.S.A.
Vol. 1, pp. 95–118

Allokotosaurian archosauromorphs (i.e., trilophosaurids and azendohsaurids) are known from Middle Triassic to Upper Triassic terrestrial deposits in Madagascar, Morocco, India, the United Kingdom, southeastern Canada, and the southwestern United States. In western Texas, trilophosaurids and malerisaurine azendohsaurids co-occur in Otischalkian sites, but numerous sites in the Chinle Formation-Dockum Group depobasin of Texas, New Mexico, and Arizona preserve either trilophosaurids or malerisaurines, blurring our understanding of the evolution of these groups and their potential biostratigraphic utility. Here we report an allokotosaurian assemblage from PFV 410 (the Kaye Quarry), a lowermost Revueltian locality in the upper Sonsela Member of the Chinle Formation at Petrified Forest National Park that preserves both trilophosaurid and malerisaurine azendohsaurid taxa, which indicates that these lineages may have co-occurred in the southwestern United States for ~10 million years during the Carnian to Norian. This locality is important because it preserves teeth of Trilophosaurus phasmalophos in a maxilla that may help resolve taxonomic uncertainty in that genus, and it shows that malerisaurines persisted at least for some time after the hypothesized Adamanian-Revueltian biotic turnover.


Free pdf:

Luke J.P. Rose, Andrew B. Heckert, Bruce Lauer, & Rene Lauer (2024)
Description of a new Upper Triassic fossil lungfish (Sarcopterygii: Dipnoi) locality from the Garita Creek Formation, east-central new Mexico, with a reevaluation of Late Triassic lungfish diversity in the American Southwest.
Vol. 1, pp. 145–170

Mesozoic lungfish fossils ordinarily consist of isolated tooth plates. Many tooth plates, typically assigned to Arganodus, are known from the Upper Triassic of the American Southwest. The new Homestead Site at Garita Creek is the most extensive vertebrate assemblage described from the Garita Creek Formation in east-central New Mexico. It has yielded enough new lungfish fossils (18 nearly complete and 43 fragmentary tooth plates) to qualify as the second-richest Upper Triassic lungfish site in North America. We measured the tooth plates of Homestead and several others from the Chinle, identifying multiple tooth plate morphotypes, including ones with only 4–5 ridges that fall outside the diagnosis of Arganodus, suggesting that the Homestead assemblage preserves at least two taxa. Reevaluating 32 previously published PEFO tooth plates further supports the presence of two morphologies: a more common morph we assign to Arganodus sp., and a second morph that we assign to cf. PtychoceratodusPtychoceratodus has a limited presence in North American strata but is known from the Late Triassic of Greenland. A ptychoceratodontid in the Upper Triassic of western North America greatly increases their geographic range during the Triassic and shows that they coexisted with Arganodus on at least three modern continents.


The submission deadline for the next volume (Spring, 2025) is Wednesday, January 8, 2025. We encourage a broad range of paleontological topics, time periods, and taxa. If you have any questions you can reach out to me ( or Jon Hardes (; submissions can be emailed directly to Jon.



Adam D. Marsh, Ph.D.

Lead Paleontologist, Petrified Forest National Park
Research Associate, Vertebrate Paleontology Collections, UT Austin
Research Associate, Museum of Northern Arizona
Reply all
Reply to author
0 new messages