- Actinopterygii (/ˌæktɪnɒptəˈrɪdʒiaɪ/; from actino- ‘having rays’, and Ancient Greek πτέρυξ (ptérux) ‘wing, fins’), members of which are known as ray-finned fish or actinopterygians, is a class of bony fish that comprise over 50% of living vertebrate species. They are so called because of their lightly built fins made of webbings of skin supported by radially extended thin bony spines called lepidotrichia, as opposed to the bulkier, fleshy lobed fins of the sister class Sarcopterygii (lobe-finned fish). Resembling folding fans, the actinopterygian fins can easily change shape and wetted area, providing superior thrust-to-weight ratios per movement compared to sarcopterygian and chondrichthyian fins. The fin rays attach directly to the proximal or basal skeletal elements, the radials, which represent the articulation between these fins and the internal skeleton (e.g., pelvic and pectoral girdles).
- Steven Spielberg (allthetropes.org)
Every so often someone emerges in a field and manages to not only revolutionize it, but do so several times. Steven Spielberg is one of those people, with a career that has gone uninterrupted since the mid-70’s and is one of the most influential powers in Hollywood.