#silesaurus

🧵 A herd of Silesaurus opolensis, a medium-sized basal ornithischian, alongside the crocodile relative Stagonolepis olenkae, and the giant amphibian Cyclotosaurus intermedius, all found at the Late Triassic Krasiejów locality in Poland.

Silesaurus opolensis, a basal ornithischian dinosaur once thought to be almost-a-dinosaur, a dinosauriform. This slender, beaked quadruped from Silesia in southern Poland probably fed on plants and insects, as shown by its teeth and beetle remains in fossilised feces.

Stagonolepis olenkae, a relatively small aetosaur, distant relative of modern crocodiles. This armored herbivore from southern Poland was a low browser, with forelimbs adapted for scratch-digging and a shovel-like snout tip, likely used to unearth roots and vegetation.

Silesaurus and Stagonolepis

Portrait of dinosauromorph Pisanosaurus mertii from the Late Triassic of Argentina. A partial skeleton of this reptile was discovered in rocks of the Ischigualasto Formation and described in 1967 as belonging to a basal ornithischian. Initially, the animal was even attributed to the Pisanosauridae family. Phylogenetic analyses in 2015 and subsequent years showed it as a relative or even a representative of silesaurids, a group of dinosaurs very close to dinosaurs proper. Pisanosaurus has features of both silesaurids and early ornithischians, which may indicate the relationship of these groups. Judging by the single specimen, it reached a little over a meter in length. The animal's name was given in honor of paleontologist Juan Arnaldo Pisano.

I decided to make a portrait because, due to the uncertain classification, it is not known whether Pisanosaurus was bipedal or quadrupedal. Filamentous structures are speculative.

The latest Dinosaurs Lately podcast https://dinosaurslately.blogspot.com/2026/01/episode-8-hadrosauroids-winter-2026.html targeting Hadrosauroids is out, trying to catch you up on everything that’s been published on them … lately.

#dinosaurs

A reassessment of the historical fossil findings from Bahia State (Northeast Brazil) reveals a diversified dinosaur fauna in the Lower Cretaceous of South America Bandeira, K.L.N. et al. (2024). doi: 10.1080/08912963.2024.2318406

Neonatal state and degree of necessity for parental care in Maiasaura based on inferred neonatal metabolic rates. Bert, H., et al. (2025). doi: https://doi.org/10.1038/s41598-025-06282-5

First Population Analysis in Hadrosauroid dinosaurs (Ornithopoda: Iguanodontia: Hadrosauroidea). Javier, J.M.F., et al. (2025). DOI: https://doi.org/10.1016/j.eve.2025.100072

Inside a duck-billed dinosaur: Vertebral bone microstructure of Huallasaurus (Hadrosauridae), Upper Cretaceous of Patagonia. Aureliano, T., et al. (2025). doi: https://doi.org/10.1002/ar.70040

Disparate feeding mechanics between two hadrosaurid dinosaurs support the potential for resource partitioning. Dudgeon, T.W., et al. (2025). doi: https://doi.org/10.1098/rspb.2025.0921

A new saurolophine hadrosaurid (Ornithischia: Hadrosauridae) from the Upper Cretaceous (Campanian) Hunter Wash Member, Kirtland Formation, San Juan Basin, New Mexico. Dalman, S.G., et al. (2025). https://www.researchgate.net/publication/396005330_A_new_saurolophine_hadrosaurid_Ornithischia_Hadrosauridae_from_the_Upper_Cretaceous_Campanian_Hunter_Wash_Member_Kirtland_Formation_San_Juan_Basin_New_Mexico

The Holotypes of Patagonichornis venetiorum Casamiquela 1996 and Tridigitichnus inopinatus Casamiquela 1996 Vertebrate Ichnotaxa (Late Cretaceous, Patagonia): History and Patrimonial Significance. Díaz-Martínez, I., et al, (2025). https://doi.org/10.1007/s12371-025-01211-4

Deciphering causes and behaviors: A recurrent pattern of tail injuries in hadrosaurid dinosaurs. Bertozzo, F. et al., (2025). doi: https://doi.org/10.1016/j.isci.2025.113739