Hallucigenia sparsa

Hallucigenia sparsa navigated the muddy Cambrian sea floor on seven pairs of slender, claw-tipped walking limbs while bearing pairs of rigid dorsal spines for defense against early predators. A elongated neck led to a tiny head equipped with simple visual organs and a circular mouth lined with tiny pharyngeal teeth, which helped it ingest seabed detritus or graze on soft sponges. Early paleontological interpretations famously reconstructed the creature upside down and backward, using its defensive spines as walking stilts until exceptional soft-tissue preservation revealed its true anatomy as a stem-group onychophoran.