Octopus and Squid Measures, Indices and Counts

A Guide to Frequently Used Characters, Character States and Measures

Last updated: 11/27/02

Frequently cited anatomical characters, structures, organ systems, measures and ratios employed in descriptions of cirrate and incirrate octopods are depicted in figures 1-6:

Figure 1 (click image to enlarge)

top: Opisthoteuthis sp.; bottom: Grimpoteuthis sp. Raw measure delineation points. Legend: AL (arm length), FLIn (fin length inner), FLOut (fin length outer), FuL (funnel length), FW (fin width), HW (head width), ML (mantle length), MW (mantle width), PA (pallial aperture width), TL (total length), WD (web depth).

Figure 2 (click image to enlarge)

top: Graneledone sp.; bottom: Octopus (s.l.) campbelli (Smith). Raw measure delineation points. Legend: A-E (web sectors A through E), AL (arm length), ASe (enlarged sucker diameter), ASn (normal sucker diameter), FuL (funnel length), HW (head width), ML (mantle length), MW (mantle width), PA (pallial aperture width), TL (total length), WD (web depth), 1-4R/L (arms 1 through 4 right or left).

Figure 3 (click image to enlarge)

Argonauta nodosa Solander, 1786 - In conventional incirrate (non-finned) octopuses the distal-most portion of the third right (or rarely third left) arm is...
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Steve O'Shea
Steve is an expert in the systematics and biogeography of cephalopods, and joined the TONMO.com staff in June 2002. He can be seen on the Discovery Channel documentary, Chasing Giants: On the Trail of the Giant Squid. For more information, see his Autobiography and Select Bibliography (2003). Dr. O'Shea lives in New Zealand.


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