Palp ciliation patterns of the genus Scolelepis (Polychaeta Spionidae) based on new species from the Philippines


Meeting Abstract

P2.78  Jan. 5  Palp ciliation patterns of the genus Scolelepis (Polychaeta: Spionidae) based on new species from the Philippines WILLIAMS, J. D.*; Hofstra University, Hempstead, NY biojdw@hofstra.edu

Three new species of Scolelepis (Scolelepis) were discovered in collections made on exposed beaches in the Philippines during 1999. In addition, Scolelepis (S.) hutchingsae (previously known only from Australia) was found among these samples. The morphology (including palp ciliation patterns) of the species was examined with SEM. One of the new species exhibits palps with two distinctly separated transverse rows of cilia (one long row and one short row). The long rows of cilia are 65 �m in length, the short rows 32 �m in length, and a 16 �m gap exists between rows. The ratio of long to short rows is 1.2. In addition, this species has palp sheaths with patches of cilia near insertion of palp, a feature that has not been previously noted in other members of the genus. The two other new species of Scolelepis (Scolelepis) exhibit palps with long and short rows of cilia that are indistinctly separated; the long rows are 41-45 �m in length and short rows are 24-26 �m in length. The ratio of long to short rows is 1.0 in these species. One of these species possesses small, smooth basal palp sheaths and cilia extend onto sides of the large, conical occipital tentacle, a unique feature in the genus. The palp ciliation pattern of Scolelepis (S.) hutchingsae closely matches that previously reported for the species (long rows of cilia 35 �m in length, short rows 10 �m in length and elevated on 5-10 �m lobes; rows in 2:1 ratio). All the Scolelepis exhibited necks of mucous secreting cells that were present in rows proximal to the ciliary rows. Although the functional significance of the ciliation patterns remains unknown, this feature can be taxonomically important. The palp ciliation patterns within Scolelepis (Scolelepis) will be reviewed and four distinct morphological types discussed.

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