Oh my goodness! Unless you are a Tree of Life developer, you really shouldn't be here. This page is part of our beta test site, where we develop new features for the ToL, often messing up a thing or two in the process. Please visit the official version of this page, which is available here.

Mastigoteuthis psychrophila: Description continued

Richard E. Young and Michael Vecchione
Click on an image to view larger version & data in a new window
Click on an image to view larger version & data in a new window

Figure. Dorsal view of M. psychrophila, holotype, preserved, 84 mm ML, immature male, 59°26'S, 158°36'E. Photograph by M. Vecchione. 

  1. Arms
    1. Arm suckers bear 12-18 sharp teeth on distal margin of inner ring .
      Click on an image to view larger version & data in a new window
      Click on an image to view larger version & data in a new window

      Figure. Arm suckers of M. psychrophila. Left - Oral view of arm IV suckers, holotype, 84 mm ML and paratype, 145 mm ML. Drawing from Nesis (1977). Middle - Oral view of arm sucker, holotype. Photograph by M. Vecchione.  Right - Oblique oral view of arm IV sucker, US NMNH cat. no. . Photograph by R. Young.

  2. Tentacles
    1. Tentacle whip-like; club circular in cross-section covering 40-60% of tentacle length (Nesis, 1977).
    2. Suckers number about 20 across club (Nesis, 1977); suckers number about 40 across in the NMNH specimen. Counts across the club are highly subjective.
    3. Density of suckers on club increases from base to mid-club (NMNH specimen).
    4. Average diameter of club sucker 0.15 mm (Nesis, 1977); NMNH specimen contains suckers of several sizes; 0.11 mm diameter is the largest and most common size.

    5. Click on an image to view larger version & data in a new window
      Click on an image to view larger version & data in a new window

      Figure. Club of the NMNH specimen of M. psychrophila. Left - Oral view of the club. Right - Oral view of club segment showing suckers of different sizes. Arrows point to small suckers. Photographs by R. Young. Photograph by M. Vecchione.

    Scanning electron micrographs of the suckers can be found here.

  3. Head
    1. Bridles to the funnel apparently with a deep pocket between them.

  4. Mantle
    1. Mantle and other skin, apparently, without tubercules. Nesis did not mention tubercules and no trace of tubercules is present in the skinned squid we examined.
  5. Fins
    1. Fins approximately circular in outline (Nesis, 1977).
    2. Fin length 67 % of ML, width 60-70% of ML (Nesis, 1977).

  6. Photophores
    1. Eyelid with small (0.3 mm) photophore (Nesis, 1977).
    2. Click on an image to view larger version & data in a new window
      Click on an image to view larger version & data in a new window

      Figure. Eyelid photophore of M. psychrophila. Left - Lateral view of portion of head; arrow points to eyelid photophore, NMNH no. 817317. Right - Similar view, different squid, with eyelid photophore covered by dense pigment. Damaged window to the photophore and the associated chromatophores still visible. Photographs by R. Young.

  7. Pigmentation
    1. Bright purple-carmine in fresh squid; dark purple after fixation (Nesis, 1977).

  8. Measurements and counts
  9. Squid Holotype Paratype Paratype Paratype NMNH # 817317 NMNH 884836 
    Sex Imm. male Adult male Imm. male Imm. male -- Imm. male
    Mantle length 84 143 124 88 105 85 
    Mantle width 21 22 20 27 --  22
    Fin length with tail 68 66 66 61+ -- -- 
    Fin length without tail 62* -- -- -- 59 54 
    Fin width 70 61 71 63 72 59 
    Head width 19 15+ 21 22 28 -- 
    Eye diameter -- -- -- -- 19 14 
    Arm I length 42 38 44 45 40  34
    Arm II length 58 50 56 62 59  46
    Arm III length 60 44 51 53 53  42
    Arm IV length 159 105 119 86+ 106  91.5
    Eyelid photophore length/width 0.3* -- -- -- 0.5 / 0.35 -- 
    Tentacle length 202 129 -- 156 200 145 
    Club length (% of tentacle length) 41-44% 83% -- 62% 70+% 69% 
    Club sucker diam. 0.15* -- -- -- 0.8-0.11 -- 
    Arm sucker diam.   -- -- -- 1.2 -- 
    Measurements are in mm.
    *Measurement mentioned by Nesis in text, presumably refers to holotype.
    Type-series measurements above are from Nesis (1977).


Nesis, K.N. 1977. Mastigoteuthis psychrophila sp. n. (Cephalopoda, Mastigoteuthidae) from the Southern Ocean. Zoologichesky Zhurnal, 65(6):835-842.

About This Page

University of Hawaii, Honolulu, HI, USA

National Museum of Natural History, Washington, D. C. , USA

Page: Tree of Life Mastigoteuthis psychrophila: Description continued Authored by Richard E. Young and Michael Vecchione. The TEXT of this page is licensed under the Creative Commons Attribution-NonCommercial License - Version 3.0. Note that images and other media featured on this page are each governed by their own license, and they may or may not be available for reuse. Click on an image or a media link to access the media data window, which provides the relevant licensing information. For the general terms and conditions of ToL material reuse and redistribution, please see the Tree of Life Copyright Policies.

close box

This page is a note that is attached to a leaf of the Tree of Life.

ToL notes provide brief accounts of characteristics, short summaries, commentaries, media files, taxonomic information, or identification tools for a given group of organisms.

For a more detailed explanation of the different ToL page types, have a look at the Structure of the Tree of Life page.

close box

Mastigoteuthis psychrophila

Page Content

articles & notes



Explore Other Groups

random page

  go to the Tree of Life home page