Brachioteuthis is a genus of small-to-medium sized squid (ML up to 20 cm), found in every ocean, except the Arctic. These squid occupy the first 200-300m of the water column as paralarvae and juveniles before venturing down to 3000m as adults.
"Arm squids"
- Mantle - long, slender, muscular, thin-walled
- Mantle sculpture - Smooth in most females (Females of B. linkovskyi develop epidermal tubercles); while epidermal tubercles and reticulate net developed in mature males.
- Mantle-locking cartilage and funnel-locking apparatus - Straight and simple
- Fins - Rhomboidal, heart-shaped, or sagittate (B. linkovskyi with attenuated fins.
- Photophore - Anteroventral ocular photophore may or may not be present in species.
- Tentacle clubs - Numerous small-stalked suckers in manus (>11 series); proximal dactylus with 2-4 series rows of larger suckers 2-4x the size of the adjacent sucker; dactylus with 3 or 4 sucker series.
Oral view of tentacular club of Brachioteuthis sp., western North Atlantic. Photograph by M. Vecchione.
Six species are currently recognised within this genus, although some require further investigation into their systematic status.
- B. beanii (North Atlantic)
- B. riisei (Circumglobal)
- B. behnii (Unknown, presumably Indian Ocean)
- B. bowmani (North Atlantic)
- B. picta (Circumglobal)
- B. linkovskyi (South Atlantic)
A full list of the species historically attributed to or affiliated with this genus can be found here on the World Register of Marine Species.
Geographical Distribution
Species of Brachioteuthis are found throughout the tropical subtropical waters of the world's oceans (Jereb & Roper, 2010). Brachioteuthis has been said to reside in Southern Ocean waters, however, those are likely Slosarczykovia.
Depth Distribution
Individuals have been detected between 0-3000m below the ocean's surface.
- Arms
- Arm suckers in two series.
- Buccal-crown connectives attach to ventral borders of arms IV.
- Tentacles
- Proximal region of manus of club greatly expanded with small suckers on long stalks in numerous irregular series.
- Dactylus of club with suckers in three or four series.
- Funnel
- Funnel-locking cartilage with straight groove.
- Mantle
- Mantle muscular but thin.
- Fins
- Fins short; anterior lobes free.
- Photophores
- Single, large, ventral ocular photophore may or may not be present.
- Viscera
- Compact digestive gland located well posterior to cephalic cartilage.
Individual eggs are found in oblique plankton tows taken in the upper few hundred meters of the ocean. The eggs have a distinctive ellipsoidal shape. Presumably the eggs are spawned in either loose egg masses or strings that easily break apart or are spawned individually.
Members of the family have characteristic paralarvae. The paralarvae have long necks containing a fluid-filled sac that extends as a reservoir into the body (Young, et al., 1985). Contraction of the reservoir can greatly increase the length of the neck, thereby extending the head from the mantle. This trait is present at hatching.
Ontogenetic stages of Brachioteuthis sp., Hawaiian waters. Top left - Egg. Top right - Dorsal view of hatchling, 2 mm ML, head retracted. Bottom left - Paralarva head and neck, 6 mm ML. Bottom right - Side view of the same hatchling, head retracted. Photographs by R. Young.
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