Bobtail squid are cephalopods belonging to the monotypic superfamily Sepioloidea of the order Sepiolida. Bobtail squid tend to have a rounder mantle than the similar-looking cuttlefish and have no cuttlebone. They have eight suckered arms and two tentacles and are generally quite small (typical male mantle length being between ). 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.
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
External links
- CephBase: Sepiolida
- Squid-bacteria symbiosis