Elephant-Sized Dicynodont from Triassic Period Discovered: Lisowicia bojani

Wednesday, November 28, 2018

Lisowicia bojani. Image credit: Dmitry Bogdanov / CC BY 3.0.

Paleontologists in Poland have found fossil fragments from a giant new species of mammal-like reptile that walked the Earth approximately 237 million years ago (Late Triassic period).

Named Lisowicia bojani, the ancient creature belongs to Dicynodontia (dicynodonts), a group of plant-eating, mammal-like reptiles.

“Dicynodonts were among the most abundant and diverse synapsids — early four-legged land vertebrates that gave rise to modern-day mammals — from the middle Permian (around 299 to 251 million years ago) to the early Late Triassic (around 237 million years ago),” said Dr. Tomasz Sulej from Poland’s Institute of Paleobiology and Dr. Grzegorz Niedzwiedzki of Uppsala University.

“Fossils of Triassic dicynodonts are extremely abundant in African, Asian, and North and South Americans deposits but are comparatively poorly known from the other regions like Europe.”

Lisowicia bojani fossils are the first substantial dicynodont finds from European deposits.”

The skeleton restoration of Lisowicia bojani: (A) left humerus in ventral view; (B) left radius in lateral view; (C) cervical vertebrae in posterior view; (D) dorsal vertebrae in lateral view; (E) left pelvis in lateral view; (F) left femur in anterior view; (G) left tibia in lateral view; (H) left fibula in medial view; (I) left ulna in lateral view; (J) left scapulocoracoid in lateral view; (K) fused quadrate and quadratojugal in posterior view. Scale bars – 10 cm (A) to (K), 1 m for the skeleton. Light gray bones represent missing elements. Abbreviations: il – ilium, pu – pubis, is – ischium. Image credit: Tomasz Sulej & Grzegorz Niedźwiedzki, doi: 10.1126/science.aal4853.

Lisowicia bojani reached an estimated length of more than 14.7 feet (4.5 m), height of 8.5 feet (2.6 m), and body mass of 9 tons.

It had erect-gait forelimbs, suggesting upright limb posture, like that of modern large mammals such as rhinoceroses and hippopotami. Previously, Triassic dicynodonts were characterized only with sprawling forelimbs (the gait of reptiles).

“The find of Lisowicia bojani shows that at least one dicynodont lineage also participated in the ‘push for gigantism’ at the same time as the sauropodomorphs, but also suggests that their evolutionary history in the Late Triassic is poorly documented,” the paleontologists said.

“This discovery changes our ideas about the latest history of dicynodonts, mammal Triassic relatives,” Dr. Sulej said.

“It also raises far more questions about what really make them and dinosaurs so large.”

“Dicynodonts were amazingly successful animals in the Middle and Late Triassic. Lisowicia bojani is the youngest dicynodont and the largest non-dinosaurian terrestrial tetrapod from the Triassic,” Dr. Niedzwiedzki added.

“It’s natural to want to know how dicynodonts became so large. Lisowicia bojaniis hugely exciting because it blows holes in many of our classic ideas of Triassic ‘mammal-like reptiles’.”

The research was published in the journal Science.

_____

Tomasz Sulej & Grzegorz Niedźwiedzki. An elephant-sized Late Triassic synapsid with erect limbs. Science, published online November 22, 2018; doi: 10.1126/science.aal4853

Source: www.sci-news.com

Web Hosting