Short Sunfish

Description

Mola ramsayi has a relatively small mouth and its teeth fused into a parrot-like beak. It can reach up to 3.3 m (11 ft) in length and 2,300 kg in mass, making it one of the two heaviest bony fish on Earth, only matched by its congener, the ocean sunfish. Their body is flat and round, with large fins that they swish back and forth to propel themselves with as they swim horizontally. Their skin has rough denticles, leathery texture, with brown and gray coloring with pale blotches until death when they turn white. Both mola species have no caudal bones, ribs, and pelvic fins and have fused vertebrae, leaving only their median fins to propel themselves. It can be recognized from the Mola mola by their lesser number of ossicles and lacking the vertical band of denticles at its base.

M. alexandrini was found to be synonymous with M. ramsayi in July 2017 and can be distinguished by their unique characteristics of head bump, a chin bump, rectangular body scales, and rounded clavus. Although adult sunfish look generally similar, they are distinguishable using the seven characteristics: number of clavus fin rays (Yoshita et al 2009), number of clavus ossicles (Yoshita et al 2009), shape of clavus margin (Yoshita et al 2009), presence of head bump (Yoshita et al 2009), proportion of body length compared to body height (Yoshita et al 2009), shape of body scales (Fraser-Brunner 1951), and the presence of a chin bump (Sawai et al. 2017).

Distribution

Mola ramsayi is found in the southwest Pacific, especially around Australia and New Zealand, and the southeast Pacific around Chile. Its range also extends to the southeast Atlantic near South Africa. This species is found in pelagic-oceanic temperate waters.

Diet

They consume a large amount of jellyfish, as they are in vast amounts despite their low nutritional content, but they will also eat brittle stars, small fish, plankton, algae, salps, and mollusks.