ON THE ANATOMY OF THE CENTRAL-NERVOUS-SYSTEM OF PHYLLODOCIDAE (POLYCHAETA) AND THE PHYLOGENY OF PHYLLODOCID GENERA - A NEW ALTERNATIVE

A reinvestigation of the central nervous system of the Phyllodocidae a ppeared necessary as the existing literature proved insufficient for d etailed comparisons with other polychaete families. Many earlier opini ons turned out to be quite contradictory, especially as concerns the m orphological value of the anterior end appendages. In the present pape r the microanatomy of the brain and the anterior ventral cord, as well as the innervation of, inter alia, the cephalic appendages, the nucha l organs and the alimentary canal of Eulalia viridis (main object of s tudy), Eumida sanguinea, Pterocirrus macroceros, Sige fusigera, Eteone picta, E. foliosa, Phyllodoce groenlandica, P. longipes, P. mucosa, P aranaitis wahlbergi, Notophyllum foliosum and Nereiphylla lutea are de scribed. The results are summarized in schematic diagrams and compared with corresponding observations on other polychaete families. Thereby , some earlier opinions about the nature of the cephalic appendages of the Phyllodocidae are strengthened while others are rejected. Most si gnificantly, it is concluded that the so-called ventrolateral antennae of phyllodocids are homologous with the palps of other polychaetes an d the median antenna found in certain genera is homologous with the nu chal papilla found in most other genera of the family. These partly ne w or revised characters and character states formed the basis for a re consideration of earlier ideas about the phylogeny of the Phyllodocida e: a new alternative. (C) 1998 The Royal Swedish Academy of Sciences. Published by Elsevier Science Ltd. All rights reserved.