Resumen

OKOLODKOV, Yuri B.. Further observations on a hypothecal pore in the genus Protoperidinium Bergh (Dinoflagellata). Hidrobiológica [online]. 2003, vol.13, n.4, pp.263-269. ISSN 0188-8897.

The data on 21 Protoperidinium species (including 8 species assigned to the genus Peridinium, which supposedly also belong to the genus Protoperidinium) with a hypothecal pore on the first postcingular plate are summarized. The hypothecal pore is shown to be present not only in the species with the first apical plate of the para-type, but also in some species with the meta-type. It is confirmed that the pore is almost exclusively associated with the hexa second intercalary plate. The pore is thought to be present in closely related species and to be a reliable diagnostic feature to differentiate Protoperidinium species. At least five groups of morphologically similar and supposedly related taxa can be distinguished: (1) Protoperidinium affine, P. pallidum and P. pellucidum; (2) P. curvipes and P. variegatum; (3) P. diabolum and P. dodgei; (4) P. cruciferum, P. cf. cruciferum, Protoperidinium sp. 1 (meta-hexa) and Peridinium acutum; (5) P. ovum and Protoperidinium sp. 2 (para-penta).

Palabras llave : Dinoflagellates; hypothecal pore; Protoperidinium; thecal morphology.