Bobtail squid

Bobtail squid have a symbiotic relationship with bioluminescent bacteria (Aliivibrio fischeri), which inhabit a special light organ in the squid's mantle. The luminescent properties of the bacteria regulate gene expression in the light organ. The bacteria are fed a sugar and amino acid solution by the squid and in return hide the squid's silhouette when viewed from below by matching the amount of light hitting the top of the mantle. This method of counter-illumination is an example of animal camouflage. The organ contains filters which may alter the wavelength of luminescence closer to that of downwelling moonlight and starlight; a lens with biochemical similarities to the squid's eye to diffuse the bacterial luminescence; and a reflector which directs the light ventrally. == Reproduction ==

Sepiolida are iteroparous and a female might lay several clutches, each of 1–400 eggs (dependent on species), over her estimated one-year-long lifetime. The eggs are covered with sand and left without parental care. Symbiosis with A. fischeri from the surrounding seawater is initiated immediately upon hatching, and the bacteria's colonisation of the juvenile light-organ induces morphological changes in the squid that lead to maturity. == Classification ==

'' from East Timor About seventy species are known. Sepiolid taxonomy within the coleoid cephalopods is currently controversial, thus their position is subject to future change.{{cite journal |author=McFall-Ngai, M.J. |title=Consequences of evolving with bacterial symbionts: Insights from the Squid-Vibrio Associations |journal=Annual Review of Ecology and Systematics Extant taxa only: • Class Cephalopoda • Subclass Nautiloidea: nautilus • Subclass Coleoidea: squid, octopus, cuttlefish • Superorder Decapodiformes • Order Bathyteuthida • Order Idiosepida: pygmy squids • Order Myopsida • Order Oegopsida • Order Sepiida: cuttlefish • Order Sepiolida: bobtail squid • Superfamily Sepioloidea • Family Sepiadariidae • Family Sepiolidae • Order Spirulida: ram's horn squid • Superorder Octopodiformes: octopus, vampire squid == References ==