Triassic Herbivore Had an Entirely Different Approach to Feeding Than Previously Thought

A TriassicThe Triassic is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.9 million years ago, to the beginning of the Jurassic Period 201.3 million years ago. It is the first and shortest period of the Mesozoic Era and is subdivided into three epochs: Early Triassic, Middle Triassic and Late Triassic.”>Triassic herbivore, known for its supposed similarities to a modern-day ostrich, has been revealed to have an entirely different approach to feeding than previously thought, according to research involving UCL and University of BirminghamFounded in 1825 as the Birmingham School of Medicine and Surgery, the University of Birmingham (informally Birmingham University) is a public research university located in Edgbaston, Birmingham, United Kingdom. It is a founding member of both the Russell Group, an association of public research universities in the United Kingdom, and Universitas 21, an international network of research-intensive universities. ”>University of Birmingham researchers.

The new findings, published in The Anatomical Record, reveal a much broader diversity of herbivore behavior during the Triassic period than has been recognized to date.

Called Effigia, the animal was about the size of a gazelle and lived in North America around 205 million years ago. Its fossil remains were found in the Ghost Ranch Quarry in New Mexico in the 1940s, although the material was not formally described by paleontologists until 2006.

The remains had been relatively poorly preserved in the quarry and the skull, in particular, was quite badly deformed, making accurate reconstruction problematic. Early analysis of the specimen concluded that it belonged to the group of reptiles that includes crocodylians and birds and which started to flourish in the Triassic period.

Although more closely related to crocodylians, Effigia’s lightweight body, elongated neck, large eyes, and beak shared many similarities with a modern-day ostrich, leading researchers to believe the animal fed by pecking plant material from the ground.

But new analysis of the specimen, led by experts at the University of Birmingham alongside scientists at UCL, University of BristolThe University of Bristol, a red brick research university in Bristol, England, received its royal charter in 1909. However, it can trace its history back to 1876 (as University College, Bristol) and 1595 (as Merchant Venturers School). It is organized into six academic faculties composed of multiple schools and departments running over 200 undergraduate courses.”>University of Bristol, University of YorkEstablished in 1963, the University of York is a plate glass research university, located in the city of York, England. It’s a member of the Russell Group of research-intensive British universities. It is a collegiate university with nine colleges: Derwent, Langwith, Alcuin, Vanbrugh, Goodricke, Wentworth, James, Halifax, and Constantine.”>University of York, Virginia Tech, and Natural History Museum, has revealed this animal was probably an entirely different type of herbivore than previously thought.

The team used new CT scans of Effigia’s skull which revealed a much more accurate reconstruction of the animal. This included new information about the shape of the skull, such as a more rounded, bulbous brain cavity and curved upper and lower jaws. Unlike an ostrich bill, which is more rounded, Effigia’s bill is more concave with jaws that open and close a bit like a pair of shears.

The team used this information to model the effects of different forces acting on the skull, including what happens when the animal pecks at the ground. By modeling the forces the skull would need to withstand in order to feed by pecking, the researchers calculated that Effigia’s skull would probably have shattered. Instead, they suggest, the animal would be more likely to use its jaws to snip off and nibble pieces of soft plant material such as young shoots, or ferns.

Lead researcher Dr. Jordan Bestwick (University of Birmingham) said: “The herbivores we already recognize in the Triassic period fed either by digging for roots, such as the pig-like aetosaurs, or reaching for leaves high up in the treetops, like the long-necked sauropods. These two-legged browsers with a weak bite are unique to this period and show a previously unrecognized diversity among the herbivores of this period.”

Co-author Dr. Laura Porro (UCL Cell & Developmental Biology) added: “Traditionally in paleontology, we assumed that animals which look similar must have had similar lifestyles. What cutting-edge, rigorous methods such as those applied in this paper are showing us, is that even subtle differences in body shape can have big consequences for what animals can do, and can indicate very different behaviors and diets. It will be interesting to see what we discover as we apply these techniques to more and more fossil species.”

Reference: “Cranial functional morphology of the pseudosuchian Effigia and implications for its ecological role in the Triassic” by Jordan Bestwick, Andrew S. Jones, Sterling J. Nesbitt, Stephan Lautenschlager, Emily J. Rayfield, Andrew R. Cuff, David J. Button, Paul M. Barrett, Laura B. Porro and Richard J. Butler, 29 November 2021, The Anatomical Record.
DOI: 10.1002/ar.24827