phylum mollusca

PHYLUM MOLLUSCA

PHYLUM MOLLUSCAInvertebratesFreshwater, marine, & terrestrial Largest marine phylum

23% of named marine species

Mantle Radula Ventral foot

CLASS CEPHALOPODASquids, octopods, cuttlefish, NautiloideaBilateral symmetryMarineArms or tentacles

ORDER TEUTHIDA – SQUIDS 8 arms in pairs of 22 tentacles (usually longer)Largest eye-to-body ratio

FAMILY LOLIGINIDAE“pencil squids”Body tapers to a pointArms are partially retractableBuccal membrane has 7 lappets

Sepioteuthis sepioideaCaribbean reef squid

Cigar-shaped bodyArms shorter than body10-20 cm longFins extend almost whole length of body

Undulate rapidly as they swim

Sepioteuthis sepioideaUnique behaviors

Pointing bodies upward prior to striking preyCurling upward during territorial disputesPointing head-down when approached by predators

Found in Caribbean sea and off the coast of Florida

Young congregate in turtle grassesDie after reproducing

(like other cephalopods)First squid to be observed “flying”?

Squid Flight

ORDER OCTOPODA8 armsNo shell

FAMILY OCTOPODIDAEMajority of know octopods Bottom-dwelling Suckers in one or two seriesOne arm modified as open sperm groove in

males

Octopus briareusCaribbean reef octopus“Chunky” body compared to arms40 – 60 cm long, up to 1.5 kgDark ring around eyeNo dark borders on suckers

Octopus briareusCannibalistic when confined in small tanks

with othersNocturnal huntersReflective skin is easy to see at nightUses chromatophores for camouflage

Disguise themselves as other species or objectsOne of the most intelligent invertebratesVery little sexual dimorphismAlso die after reproducing

Females live long enough to guard eggs