Cephalopod beak guide for the southern ocean : an update on taxonomy
Résumé
Cephalopods play an important
role in the Antarctic ecosystem, being
consumed by a wide range of predators
such as whales, fish, seals, albatrosses and
penguins. To understand predator-prey
interactions between top predators and
cephalopods, effort has been put into the
development of methods to determine the
identity and size of world cephalopods
using beaks since the 1950s (Clarke 1962a,
b; Clarke 1966; Clarke 1977; Clarke 1980;
Clarke 1986; Kubodera & Furuhashi 1987;
Fiscus 1991; Smale et al. 1993; Xavier et
al. 2007). The most used beak guide
worldwide (Clarke 1986) is now out of
print and is in need of urgent revision with
additional material (Santos et al. 2001).
Also, several new cephalopod species for
the Southern Ocean have been recently
described taxonomically, whose beaks need
to be described and/or included in a guide
(e.g. Collins & Henriques 2000; Lipinski
2001; Allcock & Piertney 2002).
New efforts in the Southern
Hemisphere allowed a new cephalopod
beak guide to be produced (Lu &
Ickeringill 2002), covering 75 species of
cephalopods in Australian waters. Also
new internet technology has been used to
create a website to aid beak identification
(http://research.kahaku.go.jp/zoology/
Beak-E/index.htm) for Japanese waters. However, a cephalopod beak guide for the
entire Southern Ocean is nonexistent and
urgently needed.
Here, we specifically aim to describe
the main cephalopod beaks from species
found in the diet of predators from the
Southern Ocean (defined as south of the
Subtropical Front) and adjacent waters
in order to assist scientists and students
interested in identifying cephalopods by
the means of their beaks. Special attention
was paid to providing photographs of
typical beaks found in the diets of adults
and juveniles when relevant. As a new tool
applied to marine ecology, 3-D computer
images of the most important lower beaks
are also provided, where it is possible to
rotate each beak 360 degrees and zoom in
and out of particular key features of beaks
in three dimensions. In addition, a review
of the allometric regressions available is
provided in order to relate cephalopod beak
size to mantle length and mass as well as
a review of the predators feeding on those
cephalopod species.