The Ragfish, Icosteus aenigmaticus, became known to science in 1880, when Lockington obtained two juvenile specimens from a fish market in San Francisco. The two specimens were unfortunately lost in a fire caused by an earthquake that devastated California in 1906.
Lockington described the ragfish as being nearly scaleless (only spinous scales on the lateral line) with bony prickles on the fin rays of each fin. Purple spots and blotches are distributed over a yellowish-brown ground colour, a round caudal fin, and small pelvic fins.
Seven years later Tartelton H. Bean received a large fish (approximately 182cm) that Mr. Charles Willoughby found in Damon, Washington. Bean recognised the close resemblance to the Ragfish but based on some morphological differences described it as a different species, Acrotus willoughbyi, in honour of its collector, in 1888.
73 years later Clemens and Wilby realized that Icosteus aenigmaticus and Acrotus willoughbyi are the juveniles and adults of the same species. The relationship of the Ragfish to other fishes remains enigmatic, and many systematists have placed the Ragfish close to the butterfishes and their relatives (Stromateoidei), with which it shares a superficial resemblance.
* This article was originally published in the last issue of the STAGES newsletter. Consider joining the Early Life History Section of AFS for only 15$ to connect with this dynamic community. JOIN HERE