GASTROPODS ▸ Class Gastropoda ▸ Univalve or having a lost or reduced valve CHAPTER 12 MOLLUSCS GASTROPODS GASTROPODS ▸ Torsion ▸ Coiling ▸ Puts gills and mantle cavity up front (no sediment) ▸ Planospiral ▸ Allows foot to be pulled in last as protection ▸ Conispiral ▸ results in self fouling... ▸ dextral vs. sinistral anus anterior mantle cavity anus posterior mantle head head cavity mouth mouth foot GASTROPODS GASTROPODS ▸ Coiling ▸ Mode of Nutrition—varied ▸ Planospiral ovotestis ▸ Mostly rasping with radula ▸ Conispiral eye ▸ Some predaceous— (Conus spp.) ▸ dextral vs. sinistral lung digestive tract kidney GASTROPODS ▸ Internal structure/function ▸ Respiration SLIME! ▸ Air brought in through a pneumostome in pulmonates ▸ Reproduction GASTROPODS GASTROPODS ▸ Classification—subclasses ▸ Pulmonata NUDIBRANCHS ▸ polyphyletic ▸ Prosobranchia ▸ Opisthobranchia GILLS CERATA RHINOPHORES TUBERCLES CEPHALOPODS CEPHALOPODS ▸ Class Cephalopoda— ▸ Squid ▸ Reduced or lost shell in most ▸ some huge! ▸ Chambered Nautilus ▸ (Architeuthis dux, (Nautilus)? Mesonychoteuthis ▸ Cuttlefish hamiltoni) ▸ cuttlebone ▸ often exaggerated ▸ chambers connected by a siphuncle ▸ Reduced to a pen in squid GIANT SQUID VS. CEPHALOPODS SPERM WHALE ▸ Giant squid have been found all over the world LEGENDARY INVERTEBRATE CEPHALOPODS CEPHALOPODS ▸ locomotion INTERNAL ANATOMY ▸ Siphon used for jet propulsion (derived from foot) ▸ respiration ▸ pair of ctenidia ▸ Closed circulatory system with multiple hearts ▸ Systemic heart ▸ Branchial or accessory hearts CEPHALOPODS CEPHALOPODS ▸ feeding ▸ Reproduction— ▸ Predaceous ▸ dioecious ▸ Chitinous beak ▸ direct development ▸ blue-ringed octopus (tetrodotoxin) ▸ intromittent structure in males ▸ Sensory ▸ intelligence? ▸ statocysts ▸ hair cells ▸ balance, posture, eye movements, ▸ color matching ▸ visual CEPHALOPODS CEPHALOPODS ▸ sepia (ink) ▸ Excellent, image-forming eyes (analogous to vertebrate eye) COLOR CHANGE ▸ Chromatophores ▸ color vision? ▸ chromatophores ▸ photocytes CEPHALOPODS CEPHALOPODS COLOR CHANGE COLOR CHANGE ▸ color vision? ▸ color vision? ▸ chromatophores ▸ chromatophores ▸ photocytes ▸ photocytes CEPHALOPODS platyhelminthes (outgroup) ▸ Subclasses Nautiloidea, Ammonoidea (extinct) and Coleoidea (all living cephalopods except Nautilus) caudofoveata ▸ orders - sepiida (cuttlefish), teuthida, octopoda, vampyromorphida solenogastres mollusca polyplacophora monoplacophora conchifera gastropoda cephalopoda bivalvia Vampyroteuthis infernalis ammonite not a nautilus scaphopoda.