Final answer:
While fossils and footprints offer invaluable insights into the gait of early land vertebrates, they only allow scientists to hypothesize potential locomotion patterns, not confirm them definitively. The Laetoli footprints and changes in the appendicular skeleton, like limb under placement and bone rotations, aid in understanding evolutionary adaptations for land movement. However, the absence of complete soft tissue data limits the ability to establish the exact gait of these vertebrates.
Step-by-step explanation:
Can the gait of early land vertebrates be determined based on limited data such as bones and footprints? While bones and footprints provide crucial clues to assessing the locomotion abilities of extinct animals, they do not afford definitive evidence of gait but instead allow scientists to form educated interpretations.
For instance, the discovery of a 75-foot trail of footprints in East Africa by Mary Leakey suggested that early hominins like Australopithecus afarensis may have had a modern striding gait around 3.5 million years ago. These Laetoli footprints are a prime example of how paleontologists use footprint analysis to infer gait patterns and locomotor abilities of extinct species. Examining the stride length, footprint depth, and overall arrangement of prints offers insights into how these early hominins moved.
In addition to footprints, the analysis of the appendicular skeleton is pivotal in understanding locomotion. Alterations in limb placement, such as the transition from splayed limbs to limbs placed under the body, indicate evolutionary adaptations for more efficient gaits on land. Key changes in the vertebrae, such as the rotation of the femur and humerus towards a more forward-facing position, provide important information on potential gait characteristics.
However, without observing the actual movement and without more comprehensive data on musculature and other soft tissues that do not fossilize well, it's difficult to state with certainty the specific gait patterns of early land vertebrates. Paleontologists must carefully analyze the available evidence and consider a range of possibilities while recognizing the inherent limitations of the fossil record.