Four Years in Notothenioid Systematics: A Molecular Perspective
271
Cotto perea can be shown to be the sister group of one of the perciform
outgroups with a significant support, then these apomorphies could
provide a new definition of the Notothenioidei. For the moment, although
the monophyly of the notothenioids (i.e. including Cotto perea and
Boviehtus) is difficult to recover from molecular studies, the definition of
the Notothenioidei in its classical sense seems to lie on a single
synapomorphy, the presence of three platelike pectoral radials [the first
(upper) one being fused with the coracoid], admitting a convergence in the
Callionymidae.
Future Studies
In spite of important recent progress, the work on notothenioid
systematics is not finished. Further phylogenetic research is needed to get
a more precise picture of the phylogeny within some families. Although
channichthyids show very little genetic divergence, a new molecular
phylogeny of channichthyid genera would be extremely useful (Chen et
al., this Vol.). Interrelationships of harpagiferids, artedidraconids and the
paraphyletic bathydraconids are not yet based on robust nodes. Much
work remains to be done also within nototheniids. It would also be very
interesting to test in a cladistic framework Voskoboynikova' s [34]
hypothesis on the interrelationships of the nototheniid genera based on the
structure of the visceral skeleton. This hypothesis assumed the monophyly
of the nototheniids; it would be fruitful to reconsider Voskoboynikova's
topology in the light of the paraphyly of the family. Finally, another topic
for further research is the identification of the sister group of the
notothenioids, a very difficult task because of the absence of definition for
the perciforms.
Acknowledgments
We would like to thank all the members of the Coordination Committee of the
"Fishes of the Antarctic Ocean" Network and the European Science Foundation
itself for providing such an invaluable opportunity for meeting and discussing
about biology and evolution of notothenioid fish. L.B. has received support from
the Italian PNRA (Programma Nazionale di Ricerche in Antartide).
References
1. Eastman JT (1993) Antarctic fish biology. Academic Press, San Diego
2. Cheng CC, DeVries AL (1991) The role of antifreeze glycopeptides and
peptides in the freezing avoidance of cold water fish. In: di Prisco G (ed)
Life under extreme conditions: biochemical adaptation. Springer-Verlag,
Berlin, pp 1-14
271
Cotto perea can be shown to be the sister group of one of the perciform
outgroups with a significant support, then these apomorphies could
provide a new definition of the Notothenioidei. For the moment, although
the monophyly of the notothenioids (i.e. including Cotto perea and
Boviehtus) is difficult to recover from molecular studies, the definition of
the Notothenioidei in its classical sense seems to lie on a single
synapomorphy, the presence of three platelike pectoral radials [the first
(upper) one being fused with the coracoid], admitting a convergence in the
Callionymidae.
Future Studies
In spite of important recent progress, the work on notothenioid
systematics is not finished. Further phylogenetic research is needed to get
a more precise picture of the phylogeny within some families. Although
channichthyids show very little genetic divergence, a new molecular
phylogeny of channichthyid genera would be extremely useful (Chen et
al., this Vol.). Interrelationships of harpagiferids, artedidraconids and the
paraphyletic bathydraconids are not yet based on robust nodes. Much
work remains to be done also within nototheniids. It would also be very
interesting to test in a cladistic framework Voskoboynikova' s [34]
hypothesis on the interrelationships of the nototheniid genera based on the
structure of the visceral skeleton. This hypothesis assumed the monophyly
of the nototheniids; it would be fruitful to reconsider Voskoboynikova's
topology in the light of the paraphyly of the family. Finally, another topic
for further research is the identification of the sister group of the
notothenioids, a very difficult task because of the absence of definition for
the perciforms.
Acknowledgments
We would like to thank all the members of the Coordination Committee of the
"Fishes of the Antarctic Ocean" Network and the European Science Foundation
itself for providing such an invaluable opportunity for meeting and discussing
about biology and evolution of notothenioid fish. L.B. has received support from
the Italian PNRA (Programma Nazionale di Ricerche in Antartide).
References
1. Eastman JT (1993) Antarctic fish biology. Academic Press, San Diego
2. Cheng CC, DeVries AL (1991) The role of antifreeze glycopeptides and
peptides in the freezing avoidance of cold water fish. In: di Prisco G (ed)
Life under extreme conditions: biochemical adaptation. Springer-Verlag,
Berlin, pp 1-14