Protoperidinium (Dinoflagellata) nuevos o interesantes de la Bahia de Manila (Filipinas)

Abstract

New or interesting Protoperidinium (Dinoflagellata) of the Bay of Manila (Philippines). This paper presents a detailed study of two new taxa, Protoperidinium bourrellyi and P. platifrons, and of two little known, controversial species of Protoperidinium (P. ventricum and P. yonedai). This study is based on a small sample of plankton collected in the Bay of Manila in September 1988, kindly sent by J. L. MacLean. Protoperidinium bourrellyi sp. n.. differs from other spheric species without spines by its little descending, almost circular cingulum, and its Meta hexa plate pattern. P. platifrons sp. n. strongly resembles P. ventricum (Abé) by its outline and ventral tabulation. Nonetheless, it is easily differentiated by its almost circular cingulum, lack of antapical concavity, by having three (instead of two) intercalary plates, and by its peculiar contour in side view showing a strong anterior dorsal concavity and a wide and somewhat slanting apical truncation. Their sulcal plates are different. The first description of P. ventricum (Abé) did not mention the cingular and sulcal plates. Abé's brief last complementary study only adds confusion with contradictory statements which seem the result of mixing two taxa, P. ventricum and P. platifrons. In this paper the description of P. yonedai (Abé) is completed and this taxon is compared with P. latispininum (Mangin), which was overlooked by Abé. The present study shows that both taxa are very much alike and that the independence of P. yonedai is therefore dubious. Notwithstanding, it is convenient to maintain it because of some differences in contour, proportions, protoplasm, and especially in sulcal plates, pending a better knowledge of the range of variaton of both taxa.