Mollusca · mollusks

Hawaiian bobtail squid

Euprymna scolopes

Sepiolidae · bobtail squidsIUCN: Data Deficient

A tiny nocturnal squid that hosts glowing bacteria in a light organ.

Fun factIts bacteria glow to cancel out its moonlit shadow from below.

Waters
Indo-Pacific
Depth zone
Coastal shallows & estuaries
Diet
Small shrimp
Size
About 3 cm

Classification

Mollusca › Cephalopoda › Sepiolida › Sepiolidae

  1. Kingdom Animalia animals
    • Many-celled organisms that eat other living things for energy (heterotrophs)
    • Cells have no cell walls
    • Most can move at some stage of life
  2. Clade Bilateria bilateral animals
    • Body has a left and right side that mirror each other (bilateral symmetry)
    • Head end with concentrated nerves; three tissue layers
    • Includes about 99% of all living animal species
  3. Clade Protostomia protostomes
    • In the embryo, the first opening usually becomes the mouth
    • Main nerve cord runs along the belly (ventral)
    • Includes mollusks, worms, and arthropods
  4. Clade Spiralia mollusks, worms & kin
    • Embryos usually divide in a spiral pattern (spiral cleavage)
    • Many have a swimming larva with a band of cilia (trochophore)
    • Includes mollusks and segmented worms
  5. Phylum Mollusca mollusks
    • Soft body with a muscular foot and a fold of tissue (mantle) that makes the shell
    • Most have a rasping, tongue-like ribbon of teeth (radula)
    • Includes snails, clams, octopuses, and chitons
  6. Class Cephalopoda cephalopods
    • Foot is modified into arms and tentacles around the head
    • Large brains and camera-like eyes
    • Jet propulsion by squirting water through a funnel (siphon)
  7. Subclass Coleoidea octopuses, squids & cuttlefish
    • Shell is internal, reduced, or absent
    • Most have an ink sac and color-changing skin cells (chromatophores)
    • Includes octopuses, squids, and cuttlefish
  8. Superorder Decapodiformes squids & cuttlefish
    • Ten appendages: eight arms plus two longer feeding tentacles
    • Includes squids, cuttlefish, and bobtail squids
  9. Order Sepiolida bobtail squids
    • Small, round-bodied squids with ear-like fins
    • Many host glowing bacteria in a light organ
  10. Family Sepiolidae bobtail squids
    • Bobtail squids that bury in sand by day
    • Use symbiotic bacteria for counter-illumination
  11. Genus Euprymna
    • Species in the same genus are very close relatives and often look alike.
  12. Species Euprymna scolopes Hawaiian bobtail squid

Closest relatives in the guide