Ocean SunfishMola mola

Taxonomy

• Phylum: Chordata• Subphylum: Vertebrata• Class: Actinopterygii• Division: Teleostei• Order:Tetraodontiformes

(triggerfish, boxfish, porcupine fish, pufferfish)

• Family: Molidae• Genus, Species: Mola

molahttp://divegeeks.com/images/SDShark/mola1.jpg

Teleost and Tetradontiformes• Division Teleostei – the most dominant living

fishes – Teleosts account for 96% of all living fishes

• Order Tetradontiformes – the most highly derived fishes – “The pinnacle of teleostean evolution”– Characterized by a high degree of fusion or loss of

numerous bones in the head and body– Date back to the early Eocene (55 to 38 million years

ago)

• World’s heaviest bony fish• Can grow to be 2m long and weigh as much as 1000kg

(2200 pounds) • The largest mola ever recorded was 2235 kg (4,927 lbs). • It measured 3.1 m (10 ft) from snout tip to "tail" fin and

4.26 m (14 ft) from dorsal fin to anal fin tip

http://www.amonline.net.au/fishes/fishfacts/fish/mola.htm

www.mbayaq.org/aa/ timelineBrowser.asp?tf=72

                           

• Molas have a large number of cartilaginous elements or cartilage-lined bones in their skulls and in their fin supports.

• The body is essentially rectangular in side view with very tall, thin dorsal and anal fins that propel the fish

• They lack a true tail but have a “pseudocaudal” tail fin made up primarily of dorsal and anal fin rays

http://www.groton.k12.ct.us/WWW/fsr/student/spr04/Jessi/FISH.htm

http://www.bidp-balidiving.com/assets/images/page/BIDP1810%20Mola.jpg

• They lack true teeth and instead have tooth plates that are shaped like a beak

• Mola mola comes from the latin word “millstone”• Their aptly named “sunfish” because they are usually

found basking on their sides at the surface

http://cordellbank.noaa.gov/images/wildlife/mola.jpg

http://www.amonline.net.au/fishes/fishfacts/images/sunteeth.jpg

Mola diets

• Mostly pelagic feeders• Diet consists of jellyfish, Portuguese man-o-

war, ctenophores and salps. • Squid, sponges, serpent star bits, eel grass,

crustaceans, small fishes and deepwater eel larvae have also been found in M. mola guts

• Indicating that they forage both at the surface, among floating weeds, on the seafloor and into deep water

Reproduction• Spawning habits

unknown• Capable of producing

300 million eggs, an apparent record among fishes

• After hatching, the larvae look more like pufferfish. They measure just 2.5 mm

• As they grow the spines disappear, as do their tails

http://www.oceansunfish.org/lifehistory.html

Molas and parasites • Molas are infamous

for their impressive parasite load

• Up to 40 genera have been found on one individual

• Could bask on side to let gulls remove parasites

http://www.amonline.net.au/fishes/fishfacts/images/mmolapar.jpg&imgrefurl

Parasites cont’d

• Molas have been seen frequenting kelp beds as well as other cleaning stations

Predators

• Large portion of bycatch in Pacific

• Market in Asian culture

• Sea lions• Orcas• Parasites

Molidae evolution

• Highly derived group – The most advanced tetraodontiforms are the three species of temperate and tropical molas (Molidae)

• Molidae has returned anatomically to a starting point in fish evolution

• It is therefore important to bring up that evolution does not mean moving from primitive to advanced forms

“The mola’s rediscovery of the utility of cartilage underscores the observation that all living fishes are the successful result of the trial and error processes of mutation and natural selection”

The Diversity of Fishes, Helfman G.S., B.B. Collette, and D.E. Facey, Massachusetts, Blackwell Science, Inc. 1999

http://www.oceansunfish.org/lifehistory.html