G. plena was described from a single octopod and many details are lacking. A redescription based on new specimens from the type locality is badly needed.

1. Arms and web
   1. Arms I and II longer than arms III and IV.
   2. Arms I with about 55 suckers, 30 within web.
   3. Arm tips with 15-20 closely-spaced suckers.
   4. Suckers in arm center separated by about one sucker diameter.
   5. Largest suckers (2.5 mm diam.) at basal third of arm, suckers near mouth very small.
   6. Slight tendency for suckers to become alternate at basal third of lateral arms.
   7. Cirri short (3-4 mm).
      
      
2. Eyes
   1. Relatively small (12 mm diam.).
      
      
3. Shell
   1. Not described.
      
      
4. Color (in alcohol)
   1. Body and aboral surfaces of web yellowish flesh-color with translucent, gelatinous appearance.
   2. Fins deep brown, darker toward tips.
   3. Oral surfaces of arms and web dark purplish-brown.
   4. Suckers dull brownish-yellow.


5. Measurements
   • Total length - 185 mm.
   • Mantle length to mantle opening - 57 mm.
   • Mantle width at base of fins - 58 mm.
   • finspan - 130 mm.
   • Fin length - 32 mm.
   • Fin width - 24 mm.
   • Eye diameter - 12 mm.
   • Length, Arm I - 125 mm.
   • Length, Arm II - 120 mm.
   • Length, Arm III - 110 mm.
   • Length, Arm IV - 95 mm.
   • Web depth, Sector A - 70 mm.
   • Web depth, Sector B - 60 mm.
   • Web depth, Sector D - 55 mm.
   • Web depth, Sector E - 35 mm
   • Sucker count - 55 - 60*
   • Diameter largest sucker - 2.5 mm.
   • Length of longest cirrus - 4* mm.
   • Location of largest suckers - Sucker positions 10 - 28*.

Comments

The above description is taken from Verrill (1885).

Collin Martin writes: "I have examined the type (only specimen) of plena, which is in poor condition, and is presently a valid species of Grimpoteuthis. Further material is needed from the type location to evaluate it properly."

Among other Atlantic species, G. plena cannot be clearly separated but may differ from:

• G. boylei in geographic distribution (Western vs Eastern North Atlantic) and the shorter cirri (1.2-1.6x vs 1.9x,males, 2.2x, females). What little is known about G. plena suggests that it is very close to G. sp. B.(Collins, 2003).
• G. challengeri in the lesser number of suckers (55-60 vs 63-72) and the shorter cirri (1.2-1.6x vs 2.5x in males, 3.5x in females) (Collins, 2003).
• G. discoveryi in geographic distribution (Western vs Eastern North Atlantic) and shallower depth habitat (<2000 m vs >2600 m) (Collins, 2003).
• G. megaptera in having a much larger and longer body, smaller fins and relatively larger eyes, larger, less prominent and more closely-packed suckers, and shorter, fatter cirri (Verrill, 1885).
• G. wuelkeri in having fewer suckers (55-60 vs 60-70) (Collins, 2003).

Western Atlantic: between New York and Bermuda

North West Atlantic, West North Atlantic

Holotype for Cirroteuthis plena Verrill, 1885
Catalog Number: USNM 39908
Collection: Smithsonian Institution, National Museum of Natural History, Department of Invertebrate Zoology
Preparation: Isopropyl Alcohol
Year Collected: 1884
Locality: 150 Miles E. Of Coast., New Jersey, United States, North Atlantic Ocean
Depth (m): 1962 to 1962
Vessel: Albatross R/V

bathyal

Depth range based on 2 specimens in 1 taxon.
Water temperature and chemistry ranges based on 2 samples.

Environmental ranges
  Depth range (m): 944 - 1962
  Temperature range (°C): 3.382 - 4.505
  Nitrate (umol/L): 17.908 - 18.310
  Salinity (PPS): 34.964 - 34.985
  Oxygen (ml/l): 5.855 - 6.170
  Phosphate (umol/l): 1.193 - 1.198
  Silicate (umol/l): 12.295 - 15.484

Graphical representation

Depth range (m): 944 - 1962

Temperature range (°C): 3.382 - 4.505

Nitrate (umol/L): 17.908 - 18.310

Salinity (PPS): 34.964 - 34.985

Oxygen (ml/l): 5.855 - 6.170

Phosphate (umol/l): 1.193 - 1.198

Silicate (umol/l): 12.295 - 15.484
 
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.

The type locality is: 37°35'N, 71°18.8'W, 2,000 m depth.