Species of Heteroteuthis are the most oceanic members of the subfamily. They are capable of producing brilliant luminescence from their bacterial photophore or secreting luminescent clouds, in a variety of forms, from it. Their large visceral photophore is seen in the left photograph below with the mantle cut open; a closer view is seen to the immediate right. The two large pores on the photophore surface enable the luminescent material to be extruded from the underlying glands. The heavy covering of iridophores that provide the variety of colors seen in the photographs appear to act as a color filter and shutter for the bioluminescence. Other members of the subfamily presumably have similar luminescent capabilities but they have not been observed.

Figure. Left - Ventral view of H. hawaiiensis with the ventral mantle removed, female, Hawaiian waters. Middle - Close-up view of the same photophore. Left - See-through side view of H. hawaiiensis showing relationship between the ink sac, which surrounds the back of the photophore, the photophore and the ventral mantle shield which may act as a diffuser of the bioluminescence. Photographs by R. Young; drawing modified from Young (1977).

Brief diagnosis:

A heteroteuthin with ...

• ventral mantle shield confined to anterior half of mantle.
• fins attached posteriorly on mantle.
  

1. Arms
   1. Right arm I and II hectocotylized in males (see photograph): arm bases bare and fused; area of fusion holds single large gland; right arm II broadened proximally and bordered by glands. (Unknown in Heteroteuthis sp. A)
      
   2. Each arm III in males with two or three greatly enlarged suckers. (Unknown in Heteroteuthis sp. A)
      

      Figure. Oral view of a living, mature male H. hawaiiensis holding onto the glass wall of an aquarium. The beaks are spread as the animal attempts to bite the glass. Photograph by R. Young.

   3. Some arms in females with bare tips.
      

      Figure. Oral view of arms I-III of a mature female H. dagamensis showing bare tips of arms I and II . Drawing by A. Hart.

2. Funnel
   1. Funnel locking-apparatus with deep, curved groove or groove with deep, angled, posterior pit.
      
      
3. Mantle
   1. Dorsal mantle margin free from head; nuchal cartilage free or fused.
   2. Ventral mantle shield confined to anterior half of mantle.
      
      
4. Fins
   1. Fin length much less than mantle length.
   2. Fins attach on posterior half of mantle.
      
   3. Posterior fin lobes rounded.

Comments

Three named species are presently recognized in the genus, H. dispar (type species, type locality - Mediterranean Sea), H. hawaiiensis (type locality - off the Hawaiian Islands), and H. dagamensis (type locality- off South Africa). H. dispar and H. hawaiiensis are very similar but specimens have never been directly compared. As a result, reliable characters to separate them are unknown. An unnamed species, Heteroteuthis sp. A, is very different from the other species but is known only from a female.

	Free nuchal cartilage	Bare arm tips, females	Greatly enlarged arm III suckers, males	Funnel locking-apparatus	Aboral keel flags
H. dispar	Yes	Arms I & II	In dorsal and ventral series	Deep, curved groove	None
H. hawaiiensis	Yes	Arms I & II	In dorsal and ventral series	Deep, curved groove	None
H. serventyi	Yes	Arms I & II	In dorsal series	Deep, curved groove	None
Heteroteuthis sp. A	No	Arms I, III & IV	Unknown	Deep, angled, posterior pit	Arms I, III

Table characters:

Geographical

Circumglobal in tropical to warm temperate oceans.

Vertical

During the day in Hawaiian waters, H. hawaiiensis less than 17; mm ML were taken mostly between depths of 250 and 350 m; squid larger than 17 mm ML were taken at greater depths of 375-650. During the night squid less than 17 mm ML were mostly taken between depths of 150 and 200 m; larger squid were taken between depths of 110 and 550 m. Males and females mature around 15-16 mm ML. In Hawaiian waters the Mesopelagic Zone begins at about 400 m during the day (Young, 1983).

As far as is known, sepiolids laytheireggsontheocean floor. Species of Heteroteuthis are the most oceanic members of the family. Nevertheless, evidence suggests that they also spawn on the ocean floor at moderate depths. Nesis (1993) found them, although broadly distributed in the open ocean, more common near seamounts and submarine ridges. Boletzky (1978) described an embryo of H. dispar that had been collected in an open bottom trawl (Mediterranean Sea, 540 m depth) and presumably had been collected on the ocean floor. Okutani and Tsuchida (2005) reported numerous mature females of H. hawaiiensis on the ocean floor at a depth of 912 m near the Ogasawara Islands.

Depth range based on 225 specimens in 7 taxa.
Water temperature and chemistry ranges based on 159 samples.

Environmental ranges
  Depth range (m): 25 - 80000
  Temperature range (°C): 1.625 - 21.549
  Nitrate (umol/L): 0.223 - 39.003
  Salinity (PPS): 34.099 - 39.014
  Oxygen (ml/l): 1.558 - 6.105
  Phosphate (umol/l): 0.091 - 2.757
  Silicate (umol/l): 1.133 - 105.408

Graphical representation

Depth range (m): 25 - 80000

Temperature range (°C): 1.625 - 21.549

Nitrate (umol/L): 0.223 - 39.003

Salinity (PPS): 34.099 - 39.014

Oxygen (ml/l): 1.558 - 6.105

Phosphate (umol/l): 0.091 - 2.757

Silicate (umol/l): 1.133 - 105.408
 
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.

Barcode of Life Data Systems (BOLD) Stats
                                        

Specimen Records:	5	Public Records:	3
Specimens with Sequences:	5	Public Species:	2
Specimens with Barcodes:	5	Public BINs:	2
Species:	2
Species With Barcodes:	2

Access Published & Released Data: Download FASTA File

Collection Sites: world map showing specimen collection locations for Heteroteuthis