Publication Date:
2020-04-21
Description:
The Octopodidae occur in virtually all benthic marine habitats; however, species in the family show little overt morphological differentiation. Subfamilies are currently defined by the presence or absence of an ink sac and the number of sucker rows (the presence of an ink sac and a single row of suckers are primitive characters) (Voss, 1988b); subfamily depth ranges arc cited in the diagnoses. Examination of external octopodid morphology through principal components analysis reveals that octopodid morphology correlates with geographic distribution. Low-latitude, shallow-water octopuses typically have narrower bodies and larger suckers on longer arms than do deep sea and high-latitude species. Sucker size inversely correlates with depth distribution, as studies of sucker functional morphology predict (Kier & Smith, 1990). The same characters contribute in a very similar manner to the discrimination of species when grouped by subfamily and when grouped by mean depth distribution. That depth distributions, which correlate with morphology and with the loss of the ink sac, contribute to the definition of these subfamilies, suggests that the subfamilies constitute phenetically similar rather than monophyletic groups. Cladistic analysis is required to reassess octopodid phylogeny.
Type:
Article
,
PeerReviewed
Format:
text
