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Nototeuthis dimegacotyle

Described by Nesis & Nikitina, 1986

Page authors: Michael Vecchione, Richard E. Young, Kat Bolstad

Nototeuthis dimegacotyle is the only species in its genus. It is known from very few specimens but appears to be a common prey item for seabirds and fishes in the Southern Ocean (Cherel, 2020).

Diagnostic features:

  • Tentacle clubs about 40% of ML, with two extremely large suckers
  • Fins long, about 60% ML
  • Southern Ocean endemic

Squid tentacle club showing many tiny suckers in the proximal region, two relatively enormous suckers in the mid manus, and
Oral view of N. dimegacotyle tentacle club. This immature female specimen (USNM 266221; ML 45 mm) was removed from the stomach of a lancetfish, Alepisaurus ferox, collected at 33° 02'S, 77° 02'W. Note that the sucker rings and sucker shape are damaged and distorted from digestion and preservation. 

Black-and-white drawing of a squid tentacle club, with hundreds of very small suckers in the proximal region, two relatively enormous suckers in the middle section, and medium-sized suckers in transverse rows of three© Kir Nesis
Illustration of tentacle club on the holotype of Nototeuthis dimegacotyle from Nesis & Nikitina (1986).

More details:

  • Mantle length to at least 240 mm
  • Head without occipital folds
  • Arms long, thick, semi-gelatinous, with large suckers of arms I-III with 12-16 tall, blunt teeth on distal side
  • Tentacle clubs with: 
    • Hundreds of small suckers (not laterally compressed), about 15-20 per transverse row, in proximal part of manus; this region is less than half of the club length
    • Dactylus with suckers in three or fewer series; ventral two series with large suckers of equal size
    • Locking apparatus of about 25 suckers in a straight line, along dorsal margin of manus and well onto tentacle stalk, where suckers are set in oblique pairs, without distinct carpal cluster

Occurs throughout sub-Antarctic waters; meso- to bathypelagic (see summary in Cherel, 2020).

Type locality: Southeastern Pacific off southern Chile at 50°38.5'S, 81°40.5'W. The holotype was taken in a tow (0-500 m over bottom of 4200 m) that also captured Gonatus antarcticus. Water temperature at the surface was 9.5°C. Additional specimens have come from 42°08'S, 147°08'W, 40°58'S, 104°22'W, 41°30'S, 108°54'W (Nesis and Nikitina, 1992) and 33° 02'S, 77° 02'W (USNM) in the South Pacific. All of the captures lie between the Southern Subtropical and the Antarctic Polar frontal zones. Nesis and Nikitina suggested that this species is a member of the notalian (southern temperate) fauna; Cherel (2020) indicated that it may reach sub-tropical waters in some regions. 

Additional details from the original description by Nesis and Nikitina (1986): 

  • Mantle drawn out into a thin, soft tail without solid support (possible artifact).
  • Fins attach to dorsolateral sides of mantle, do not join together posteriorly, and lack anterior lobes,
  • Gladius with primary conus and short free rhachis

Black-and-white drawing of a squid gladius with short rhachis and broad vanes© Kir Nesis
Ventral view of gladius of N. dimegacotyle with small piece at anterior end missing, 87 mm long, 10 mm wide. Drawing modified from Nesis and Nikitina (1992).

  • Arms with low protective membranes with large triangular trabeculae; arm suckers:
    • Large on arms I-III, up to 3.8% of ML (Arm III), with 12-16 tall, blunt teeth on distal side; proximal end smooth (drawing on near right).
    • Small on Arms IV (1/4 to 1/5th diameter of other arm suckers), with 4-6 similar but lower and more widely spaced teeth on distal margin (drawing on far right).
    • Base of each sucker stalk surrounded by two low, rounded tubercles.
  • Tentacle suckers:
    • In proximal manal suckers, teeth triangular distally on inner ring and large teeth on distal portion of outer ring (inner margin) (drawing on far right).
    • In enlarged suckers, ~45 sharp, conical teeth of similar height around entire perimeter of sucker ring, each separated about one tooth width from its neighbor (drawing on near right).
    • In dactylus and smaller distal manal suckers, about 30 long sharp teeth distributed all around the perimeter
    • In terminal pad, about 13 suckers present.

Black-and-white illustrations of four squid arm and tentacle sucker rings© Kir Nesis
Oral view of arm and tentacle suckers of N. dimegacotyle. (A) Sucker from Arm III, (B) Sucker from Arm IV, (C) Large sucker of distal manus, (D) Sucker from proximal manus. Drawings from Nesis and Nikitina, 1986.

Measurements of holotype, in mm:

    • ML, 48.5 (without tail)
    • Fin length, 29.
    • Width of single fin, 6.
    • Arms I - 35; arms II - 45; arms III - 45; arms IV - 50.
    • Club length, 18.
    • Length of locking apparatus, 21
    • Diameter of largest suckers: Arm I - 1.6, arm II - 1.8, arm III - 1.9, arm IV - 0.4.
    • Diameter of largest club sucker: Proximal manus - 0.15, distal manus - 6.5, dactylus - 0.9-1.0.
  • Cherel, Y. (2020). A review of Southern Ocean squids using nets and beaks. Marine Biodiversity, 50(6), 98.
  • Nesis, K.N., and I.V. Nikitina. (1986). New Genus and Species of Squid of the Family Neoteuthidae (Cephalopoda, Oegopsida) from the South-eastern Part of the Pacific Ocean. Zoologichesky Zhurnal, 65(2):290-294.
  • Nesis, K. N. and I. V. Nikitina. (1992). New records of oceanic squids Walvisteuthis virilis Nesis et Nikitina, 1986 and Nototeuthis dimegacotyle Nesis et Nikitina, 1986 (Cephalopoda, Oegopsida) from the South Atlantic and the South Pacific. Ruthenica, 2: 55-58.

Taxonomy

Superorder
Decapodiformes
Superfamily
Architeuthoidea