Practice question

Kinorhyncha compose microscopic pseudocoelomate ecdysozoan meiofauna universally less than 1 mm, inhabiting marine mud and sand from intertidal to deep sea. Commonly called mud dragons due to armored spiny segmented trunk comprising 11 zonites with overlapping cuticular plates armed with spines, plus anterior eversible introvert bearing rings of recurved scalids for anchoring and locomotion. They move by inching, everting head as anchor then pulling trunk. Deposit feeders on diatoms, bacteria and organic detritus. Secretive benthic habit and dragon-like armor inspire common name, while taxonomy remains challenging due to minute size and cryptic habitat requiring specialized sampling.