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Ocean SunfishMola mola

Taxonomy

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

(triggerfish, boxfish,porcupine fish, pufferfish)

• Family: Molidae• Genus, Species: Mola

mola

Teleost and Tetradontiformes• Division Teleostei – the most dominant living

fishes– Teleosts account for 96% of all living fishes

• Order Tetradontiformes – the most highlyderived fishes – “The pinnacle of teleosteanevolution”– 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

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• Molas have a large number of cartilaginous elements orcartilage-lined bones in their skulls and in their finsupports.

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

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

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

• They lack true teeth and instead have tooth platesthat 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

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 eellarvae have also been found in M. mola guts

• Indicating that they forage both at thesurface, among floating weeds, on theseafloor and into deep water

Reproduction• Spawning habits

unknown• Capable of producing

300 million eggs, anapparent record amongfishes

• After hatching, thelarvae look more likepufferfish. Theymeasure just 2.5 mm

• As they grow thespines disappear, asdo their tails

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

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Molas and parasites• Molas are infamous

for their impressiveparasite load

• Up to 40 generahave been found onone individual

• Could bask on sideto let gulls removeparasites

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

Parasites cont’d

• Molas have been seenfrequenting kelp bedsas well as othercleaning stations

Predators

• Large portion ofbycatch in Pacific

• Market in Asianculture

• Sea lions• Orcas• Parasites

Molidae evolution

• Highly derived group – The most advancedtetraodontiforms are the three species of temperateand tropical molas (Molidae)

• Molidae has returned anatomically to a starting pointin fish evolution

• It is therefore important to bring up that evolutiondoes not mean moving from primitive to advancedforms

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“The mola’s rediscovery of the utility of cartilageunderscores the observation that all living fishes arethe successful result of the trial and error processesof 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