Hot Paper: Ethan Mooney of the Reisz Lab
Recent M.Sc. Graduate, Ethan Mooney, has his second paper published this year in the Swiss Journal of Paleontology! Ethan will continue his studies at Harvard University this September as he pursues his Ph.D. Read below for full details.
PI: Prof. Robert Reisz
Title: Massospondylus embryos and hatchling provide new insights into early sauropodomorph ontogeny
Abstract: Ontogeny and patterns of growth provide crucial insights into the evolution of dinosaurs and their biology, however, ontogenetic changes of the postcranial skeleton are generally poorly known and restricted to few species. Here, we report on the discovery of embryonic, eggshell, and hatchling material of the Early Jurassic sauropodomorph Massospondylus and provide new insights into the early life stages of early-diverging sauropodomorphs. The embryos described here represent a more advanced developmental stage than previously known embryonic materials and together show eggshells with progressive degrees of resorption correlating to embryonic development. The prominent “thumb” typical of early-diverging sauropodomorph dinosaurs also appears to be precociously ossified and ontogenetically variable. Together, these new Massospondylus embryos and hatchling indicate a quadrupedal posture and the resulting growth trajectory points to an important ontogenetically influenced ecological shift predicated on a continuum of locomotory dependent postural change, from obligate quadrupeds to obligate bipeds. Other Late Triassic and Early Jurassic sauropodomorph dinosaurs known from few ontogenetic stages also fit well on the extensive growth trajectory of Massospondylus with only modest variations in skull, neck, and limb proportions. This generally conservative body plan of early-diverging sauropodomorphs likely suggests a similar postural change for the early members of this large clade that preceded the obligate quadruped sauropods.
Read the full paper, here.
Congratulations, Ethan et. al!
