TY - CHAP

T1 - Nervous and muscular systems of coronate larvae of Callopora craticula Alder, 1857 (Bryozoa: Gymnolaemata)

AU - Kotenko, O.N.

AU - Tsitrin, E.B.

AU - Shunatova, N.N.

PY - 2004

Y1 - 2004

N2 - There are two main well-known types of larvae within gymnolaemate Bryozoans. The first, cyphonaut, is typical planctotrophic larvae and is widely suggested to be the ancestral one. The second, coronate larvae, is lecithotrophic and seems to be more advanced.We described nervous and muscular systems of gymnolaemate coronate larvae using both confocal microscopy and TEM. The entire pattern of both these systems demonstrated strictly bilateral symmetry character.Muscle system (labeled with phalloidin-TRITC) consisted of three pairs of cords. Two of them laid just below the apical disc in paraequatorial plane. Another pair extended from the apical disc to the ciliated groove in saggital plane to form the neuromuscular cord. Muscle system also included ring-shaped fibers closely encircling the apical disk, and large network of fine fibers scattered over the larvae body. All muscles revealed by TEM had cellular organization.Nervous system (anti-acetylated tubulin immunofluorescence) was composed of the corona nerve, the apical ganglion and its processes extended to the vibratile plume and corona nerve. Serotonin-like immunofluorescence shows three pairs of neurons with pericarya belonging to the apical ganglion and two pairs of neurons with pericarya integrated in the corona.Our data was consistent with general patterns of nervous and muscular systems previously described for coronate larvae of several bryozoan species. Ground plane of both nervous and muscular systems seemed to be similar to those of lecithotrophic trochophores. However, there were significant differences we suggest two possible explanations for. Firstly, gymnolaemates have special cleavage type contrasting to most other Lophotrochozoans. Secondly, it is an existence of special sensory structure as the vibratile plume, or tuft, in coronate larvae.

AB - There are two main well-known types of larvae within gymnolaemate Bryozoans. The first, cyphonaut, is typical planctotrophic larvae and is widely suggested to be the ancestral one. The second, coronate larvae, is lecithotrophic and seems to be more advanced.We described nervous and muscular systems of gymnolaemate coronate larvae using both confocal microscopy and TEM. The entire pattern of both these systems demonstrated strictly bilateral symmetry character.Muscle system (labeled with phalloidin-TRITC) consisted of three pairs of cords. Two of them laid just below the apical disc in paraequatorial plane. Another pair extended from the apical disc to the ciliated groove in saggital plane to form the neuromuscular cord. Muscle system also included ring-shaped fibers closely encircling the apical disk, and large network of fine fibers scattered over the larvae body. All muscles revealed by TEM had cellular organization.Nervous system (anti-acetylated tubulin immunofluorescence) was composed of the corona nerve, the apical ganglion and its processes extended to the vibratile plume and corona nerve. Serotonin-like immunofluorescence shows three pairs of neurons with pericarya belonging to the apical ganglion and two pairs of neurons with pericarya integrated in the corona.Our data was consistent with general patterns of nervous and muscular systems previously described for coronate larvae of several bryozoan species. Ground plane of both nervous and muscular systems seemed to be similar to those of lecithotrophic trochophores. However, there were significant differences we suggest two possible explanations for. Firstly, gymnolaemates have special cleavage type contrasting to most other Lophotrochozoans. Secondly, it is an existence of special sensory structure as the vibratile plume, or tuft, in coronate larvae.

KW - larvae

KW - Bryozoa

KW - nervous system

KW - muscular system

M3 - Conference abstracts

SP - 122

BT - The 6th International Larval Biology Conference

T2 - The 6th International Larval Biology Conference

Y2 - 21 June 2004 through 25 June 2004

ER -