Most species of Grimpoteuthis are poorly known. They are somewhat less compressed in the anterior-posterior axis than are members of Opisthoteuthis and they generally have relatively larger fins. Species are closely associated with the deep-ocean floor and some species, at least, alternate between sitting on the ocean bottom and swimming above it while some others apear to be completely pelagic.

Diagnosis

Opisthoteuthids ...

• without enlarged sucker fields on arms of males.
• Areolae absent.
• Optic lobe circular in cross-section.
• One optic nerve bundle penetrates white body.
• Shell U-shaped or slightly W-shaped.
• Sucker aperature without tooth-like structures.

Species of Grimpoteuthis, as with many other species of cirrates undergo great shrinkage with fixation and preservation. The cirrate on the left, identified as G. wuelkeri by Uwe Piatkowski, was photographed directly after its capture. The photograph of the same specimen, on the right, was taken after two years in ethanol. While the relative sizes of the two have not been maintained here, note that the eyes and fins appear relatively larger after preservation.

Robson (1932) erected the genus Grimpoteuthis to include some species formely placed in Cirroteuthis. He designated G. umbellata (Fischer, 1883) as the type species.

1. Arms and web
   1. Suckers in males not greatly enlarged, not in two fields.
   2. Sucker aperatures without tooth-like structures (see Luteuthis for tooth-like structures).
   3. Cirrus length comparable to 2.5 times largest sucker diameter.
   4. Single web nodules present (arrow).
   

   Figure. Oral view of arm of Grimpoteuthis bathynectes showing single web nodule. Drawing modified from Voss and Pearcy, 1990.

2. Head
   
   1. Eyes: Large, diameter typically 1/3 of head width.
   2. Beaks: Descriptions of some species can be found here: Lower beak; upper beak.
      
      
3. Pigmentation
   1. No areolar spots
      
      
4. Fins
   1. Length approximately equals mantle width.
      
      
5. Gills
   1. Semi-sepioid (in G. innominata) or half-orange appearance.
      
      
6. Digestive system
   1. Intestine approximately equal to esophagus (including crop) in length.
   2. Digestive tract arranged in simple U-shape.
   3. Digestive gland unilobular.
   4. Radula present or absent.
   

   Figure. Side view of digestive tract of Grimpoteuthis bathynectes (?). Drawing modified from Voss and Pearcy, 1990.

7. Optic lobe and optic nerve bundles
   1. Optic lobe circular (rather than kidney-shaped) in cross-section.
   2. Single nerve bundle from optic lobe penetrates white body.
   

   Figure. Optic lobe, optic nerve bundles and white body of Grimpoteuthis abyssicola. Drawing from O'Shea, 1999.

8. Shell
   1. U-shaped, lateral walls of wings usually parallel to one another. Mid-saddle often with outer and inner surfaces convex but outer surface flat or concave in some species (eg, G. meangensis).
   2. Shoulders with or without shoulder blades.
   

   Figure. Dorsal view of shell of Grimpoteuthis bathynectes. Drawing modified from Voss and Pearcy, 1990.

Comments

The male reproductive tract shows considerable variation between species and is frequently described for new species. However the amount of variation within a species is unknown and therefore the specific value of the structures of the tract is uncertain. In addition there is some confusion regarding the identification of the various parts. Ebersbach (1915) made a careful dissection of the digestive tract of a Grimpoteuthis that he believed was G. umbellata. His illustration, relabeled, is shown on the right. The proximal glands on the sperm duct are often called "seminal vesicles." However, as Ebersbach pointed out, they are spermatophore-forming glands and should be called "spermatophore glands." A small gland (labeled "?") lies between the spermatophore and accessory glands that Ebersbach called the accessory spermatophore gland but may be Needham's sac.

Species comparisons

Species	No. arm suckers	Sucker no. at Arm I nodule	First cirrus between suckers	Length: cirrus/sucker; Male, female	Salivary glands	Gill lamellae	Eye size	Shell shoulder blades	Shell wings expanded	Shell saddle shape: Outer surface	Ocean
G. abyssicola	77	32-34	4-6	2.5x	None	8	Large	No	Yes	Convex	South Pacific
G. bathynectes	47-58	26	3-4	1.1x, 1.3x	Posterior	7-9	Large	No	No	Convex?	North Pacific
G. boylei	55-58	31	4-7	1.9x, 2.2x	Ant., Post.	7-8	1/3 HW	Weak	No	Depressed	North Atlantic
G. challengeri	63-72	34	4-7	2.5x, 3.5x	Anterior	7-8	1/3 HW	Yes	No	Convex	North Atlantic
G. discoveryi	56-61	31	3-5	1.2x, 1.6x	Anterior	6-8	1/3 HW	Weak	No	Convex	North Atlantic
G. hippocrepium	50,	25	4-5	?	?	?	?	No	No	Flat?	E. tropical Pacific
G. innominata	50-60	22-24	4-6	1x	None	7	large	Yes	Yes	Median ridge	South Pacific
G. meangensis	60-70	?	4-7	?	?	?	?	Yes	?	Flat	W. tropical Pacific
G. megaptera	?	?	?	2x	?	?	1/3 HW	?	?	?	North Atlantic
G. pacifica	52	?	6-8	2x	?	?	Large	?	?	?	W. tropical Pacific
G. plena	55	?	?	1.2-1.6	?	?	small	?	?	?	North Atlantic
G. tuftsi	63-75	?	5-7	1.5-3.5	None	7-8	Large	Yes	No?	Transverse groove	North Pacific
G. umbellata	65-68	?	4-5	1.2x	?	8	?	?	?	?	North Atlantic
G. wuelkeri	60-70	28	4-7	2.5x, 1.2x	Ant., post.	6-7	1/3 HW	Yes	No	Convex with ridge	North Atlantic

Color: Skin of red brown, orange or purple color in fresh specimens. Usually oral side more pigmented that dorsal side.

Stomach contents in G. wuelkeri and G. boylei showed polychaetes, copepods, amphipods and isopods. Mature females have few and large eggs in oviducts, measuring from 10-18 mm in length, suggesting a continuous spawning mode as observed in other cirrate octopods. Individuals of Grimpoteuthis sp. have been observed resting and crawling on the sea bottom, swimming basically by the use of fins and also by arm-web contractions. As a response to disturbance, individuals have been observed in web inversion, with arms and web upturned, oral surface facing outward, completely covering mantle, head and fins.

Species appear to be associated with the deep ocean floor in all oceans of the world.

Specimens of this genus has been collected in the Atlantic and Pacific Oceans. In the NE Atlantic, abundances of Grimpoteuthis sp. ranged from 1.3-25 individuals km-2 at depths from 1500-4850 m (COLLINS et al. 2001).

External features: body gelatinous and bellshaped. Fins medium to large, with distinct lobe near the anterior fin insertion. Thick primary web. Intermediate web absent. Each arm bears a single longitudinal row of suckers alternating with paired, medium-sized cirri. Internal features: optic lobe spherical, optic nerves pass though white body as a single boundle of fibres. Shell U-shaped with other edges of lateral walls parallel, not tapered to single fine points. The genus comprises 14 species.

Up to 115 mm mantle length.

Depth range based on 88 specimens in 17 taxa.
Water temperature and chemistry ranges based on 47 samples.

Environmental ranges
  Depth range (m): 136.41 - 4865
  Temperature range (°C): -2.028 - 4.505
  Nitrate (umol/L): 17.733 - 43.951
  Salinity (PPS): 33.954 - 34.985
  Oxygen (ml/l): 0.646 - 6.682
  Phosphate (umol/l): 1.146 - 3.279
  Silicate (umol/l): 12.295 - 182.606

Graphical representation

Depth range (m): 136.41 - 4865

Temperature range (°C): -2.028 - 4.505

Nitrate (umol/L): 17.733 - 43.951

Salinity (PPS): 33.954 - 34.985

Oxygen (ml/l): 0.646 - 6.682

Phosphate (umol/l): 1.146 - 3.279

Silicate (umol/l): 12.295 - 182.606
 
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.

Very little is known about the habits and behavior of species of Grimpoteuthis. These photographs taken off Hawaii show an unknown species of Grimpoteuthis sitting on the ocean floor (right) and swimming with its fins just above the ocean floor (left). Some species, perhaps that in the title photograph, are very delicate and unlike the species seen on the right, may be entire benthopelagic.

Barcode of Life Data Systems (BOLD) Stats
                                        

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

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