  The Bethe ansatz equations of the fundamental Sp(2N) integrable model are
solved by a peculiar configuration of roots leading us to determine the nature
of the excitations. They consist of N elementary generalized spinons and N-1
composite excitations made by special convolutions between the spinons. This
fact is essential to determine the low-energy behaviour which is argued to be
described in terms of 2N Majorana fermions. Our results have practical
applications to spin-orbital systems and also shed new light to the connection
between integrable models and Wess-Zumino-Witten field theories.
