Observations on the morphology of Truttaedacnitis clitellarius and T. lebedevi (Nematoda: Cucullanidae) from acipenserids and synonymy of the two species
Truttaedacnitis clitellarius (Ward & Magath, 1917) (Nematoda: Cucullanidae) is redescribed from the lake sturgeon Acipenser fulvescens from North America and compared with T. lebedevi (Skrjabina, 1966) from the Siberian sturgeon A. baeri. Studies on the morphology and morphometrics of the two species reveal considerable overlap with unique shared characters, such as the previously unreported position of the excretory pore at the level of the pseudobuccal capsule and arrangement of caudal papillae. This position of the excretory pore is anteriormost among all cucullanids. Although there is a trend towards smaller size of body and spicules in T. lebedevi, this reflects a long period of geographical separation and likely accounts for the minor morphological variations noted. Consequently, the two species are synonymised. The presence of one species of Truttaedacnitis, T. clitellarius, specific to freshwater acipenserids in North America and Siberia, suggests an ancient origin and slow rate of evolution for this cucullanid.
- 1 - sciences appliquees, technologies et medecines
- 2 - sciences biologiques et medicales
- 3 - sciences biologiques fondamentales et appliquees. psychologie
- 4 - phytopathologie. zoologie agricole. protection des cultures et des forets