Haliphron atlanticus Steenstrup 1861

Introduction

Females of Haliphron (= Alloposus) atlanticus are very large, reaching 400 mm ML or a total length up to 2m (Nesis, 1982). Body tissues are gelatinous; the mantle is short and broad and the head wide; the eyes are large and the short arms have a deep web. The funnel is embedded in head tissue. Males are much smaller than females but are relatively large (ca. 300 mm total length) for an argonautoid. The hectocotylus develops in an inconspicuous sac in front of the right eye which gives the male the appearance of having only seven arms (see below). The hectocotylus detaches at mating. Females brood their eggs, which are attached to the oral side of the arm bases near the mouth (Young, 1995).

Diagnosis

An argonautoid ...

• of gelatinous consistency with complex funnel locking-apparatus.

Characteristics

1. Arms
   1. Suckers mostly in two series but grade to single series near mouth.
      
      
   2. Hectocotylus with papillate lateral fringes from base to spermatophore reservoir; open spermatophore groove.
      
      
   3. Extensive web between all arms.
      image info

      Figure. Oral view of brachial crown of H. atlanticus showing deep web and sucker arrangement, ca. 70 mm ML. Drawing from Verrill, 1881.

2. Body shape
   1. Short, broad.
      
      
3. Funnel-locking apparatus
   1. Lateral folds on the funnel and corresponding grooves on the mantle.
      
      
4. Swim bladder
   1. Hydrostatic organ (swim bladder) present dorsal to digestive system.
      
      
5. Water pores
   1. Absent.

Comments

Unlike other members of the argonautoid families, Haliphron has a remnant of the true shell - a short, thick almost gelatinous stylet (Voight, 1995). H. atlanticus, like other members of the argonautoid families except species of Argonauta, has a hydrostatic organ (Bizikov, 2004).

Nomenclature

A list of all nominal genera and species in the Alloposidae can be found here. The list includes the current status and type species of all genera, and the current status, type repository and type locality of all species and all pertinent references.

Life History

As in all argonautoids, the male has its hectocotylus coiled in a sac. In Haliphron this is located beneath the right eye and due to the thick gelatinous tissue on the octopod, it is easily overlooked. Indeed one such animal was described as a new species and genus, Heptapus danae (Joubin, 1929), based on the apparent presence of only seven arms.

image info image info

Figure. Oral views of two males of H. atlanticus showing what appears to be just seven arms. Left - Photograph by Ron Gilmer. Right - Photograph by R. Young, R/V G. O. Sars, Mar-Eco cruise, North Atlantic.

A large, brooding female was observed from a submersible off Hawaii at 270 m. The octopod was drifting just above the bottom and was carrying eggs that were held within the web and near the mouth (Young, 1995). The female was badly damaged as can be seen in the photograph by the truncated dorsal arms and the crease in one of the lower arms. Presumably the female was near the end of the brooding period and would not survive long after all young had hatched. The white arrow in the video frame to the right points to the eggs. The video of this octopod can be seen at Cephalopods in Action.

image info

Figure. Oral view of a female H. atlanticus ca. 1 m in diameter, off Hawaii. brooding a small batch of eggs (arrow). Video frame from the submersible Pisces V, Hawaii Undersea Research Laboratory (from Young, 1995).

Hatchlings are rarely taken in the near-surface plankton and presumably reside in deep water (Personal observation).

Habitat

This species is widely distributed from tropical to high latitudes and occupies meso- to bathypelagic depths. It is commonly associated with slopes of land masses. The habitat of this octopod is unusual. It has been captured in bottom trawls and videotaped swimming within centimeters of the ocean floor (brooding female) suggesting a benthopelagic habitat along the slope. However, it has also been taken from the open ocean thousands of meters from the ocean floor and hundreds of miles from the nearest slope. H. atlanticus is a common food item of blue sharks off New England, USA, and sperm whales near the Azores Isl. (M. Vecchione, pers. comm.).

References

Bizikov, V. A. 2004. The shell in Vampyropoda (Cephalopoda): Morphology, functional role and evolution. Ruthenica. Supplement 3: 1-88.

Naef, A. 1921/23. Cephalopoda. Fauna und Flora des Golfes von Neapel. Monograph, no. 35.

Nesis, K. N. 1982. Abridged dey to the cephalopod mollusks of the world's ocean. 385+ii pp. Light and Food Industry Publishing House, Moscow. (In Russian.). Translated into English by B. S. Levitov, ed. by L. A. Burgess (1987), Cephalopods of the world. T. F. H. Publications, Neptune City, NJ, 351pp.

Sasaki, M. 1929. A monograph of the dibranchiate cephalopods of the Japanese and adjacent waters. Journal of the College of Agriculture, Hokkaido Imperial University, 20(Supplementary number):1-357.

Verrill, A.E. 1881. The cephalopods of the north-eastern coast of America. Part II. The smaller cephalopods, including the "squids" and the octopi, with other allied forms. Trans. Connecticut Acad. Sciences, 5: 259-446.

Young, R. E. 1995. Aspects of the natural history of pelagic cephalopods of the Hawaiian mesopelagic-boundary region. Pacific Science, 49: 143-155.