Introduction

Meroktenos (MEH-rok-TEH-nohs; “Thigh beast”) is a genus of large, early sauropod dinosaur that lived during the Late Triassic period, approximately 215 to 205 million years ago. Its fossils were discovered in what is now Lesotho, in Southern Africa. The name Meroktenos means “thigh beast,” referring to its notably strong and robust thigh bone (femur). This dinosaur was scientifically described by paleontologists Claire Peyre de Fabrègues and Ronan Allain in 2016. The fossil material now known as Meroktenos was originally considered to be a species of another early sauropodomorph, Melanorosaurus.

Description and Classification

Meroktenos was a large plant-eating dinosaur from the Late Triassic period. Scientists estimate it could grow to be about 8 to 10 meters (26 to 33 feet) long and had a sturdy, robust build. It walked on four legs, a common feature for sauropods and their close relatives. This dinosaur belongs to a group called Sauropodomorpha, which includes the famous long-necked giants like Brachiosaurus and Apatosaurus. Meroktenos is considered an early, or basal, member of the Sauropoda group, or a very close relative to the first true sauropods. Its bones show that it was one of the earlier dinosaurs to reach a large body size. It lived much earlier than the giant sauropods of the Jurassic and Cretaceous periods. The fossils of Meroktenos were first thought to belong to another dinosaur called Melanorosaurus, but further study showed it was different enough to be given its own genus name in 2016.

Distinguishing Features

Meroktenos had several features that helped scientists identify it as a unique dinosaur:

• Its thigh bone (femur) was very strong and stout, which is how it got its name “thigh beast.”
• The shaft of its femur was notably straight when viewed from the side.
• The top part of the femur, which connected to the hip, pointed upwards and slightly inwards in a specific way.
• Part of its hip bone, called the ilium, had a distinctive shape. Specifically, the section that connected to another hip bone (the pubis) was low and stretched out from front to back.

Paleoenvironment and Diet

Meroktenos lived in what is now Lesotho in Southern Africa, during the Late Triassic period. The environment at that time, preserved in rocks called the Lower Elliot Formation, was a semi-arid landscape with floodplains and rivers that probably flowed seasonally. It wasn’t a lush jungle, but more like a savanna with distinct wet and dry periods. Meroktenos shared this environment with other early dinosaurs. These included other plant-eating sauropodomorphs like Melanorosaurus and Antetonitrus, as well as various early meat-eating theropod dinosaurs. As an herbivore, Meroktenos would have fed on the types of plants available in the Triassic period, such as ferns, seed ferns, cycads, and early conifers. Its size suggests it would have needed to eat a large amount of vegetation each day.

Significance and Ongoing Research

The discovery and study of Meroktenos are important for several reasons. It provides valuable clues about the early evolution of sauropod dinosaurs, the group that would later produce the largest land animals ever to live. Meroktenos shows that some sauropodomorph lineages were already achieving large body sizes in the Late Triassic, which is significant for understanding how and when gigantism evolved in this group. Fossils like those of Meroktenos from the Southern Hemisphere (part of the ancient supercontinent Gondwana) help paleontologists understand how dinosaurs were diversifying across the globe during this early phase of their evolution. Ongoing research continues to explore the exact relationships of Meroktenos to other early sauropods and sauropodomorphs. Scientists are also working to learn more about how it lived, moved, and grew, helping to paint a clearer picture of life during the Triassic period.