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We studied the taxonomical value of morphology of notochaetae and uncini of Terebellinae for generic diagnostics in 25 species (15 genera) using scanning electron microscopy. Whenever possible, specimens collected from the type localities were studied. The usefulness of chaetal characters for generic definitions within Terebellinae is discussed.

The phylogenetic relationships of the Amphitritinae (Polychaeta: Terebellidae) were studied using parsimony analysis of 22 external morphological characters. To choose outgroups to polarize the characters, I carried out a preliminary analysis of the relationships of the four terebellid subfamilies and the Trichobranchidae. The single most parsimonious tree from the analysis supports monophyly of the Terebellidae by the presence of ventral glandular shields. However, this character is homoplasious within the Terebellomorpha, and further evaluation of the Terebellidae is recommended.ArtacamaandThelepuswere chosen as outgroups for the analysis of amphitritine genera. The generic level analysis yielded seven equally parsimonious trees, which are consistent in their topologies except for the relationships among seven genera in one large clade. In all trees,Artacamais the sister taxon to a large clade within the Amphitritinae; the Artacaminae is therefore synonymized with the Amphitritinae, which is diagnosed by the presence of double rows of uncini. Within the Amphitritinae, the status of several monotypic genera is questioned; plesiomorphic character states indicated by the analysis are discussed. The results presented are offered as working hypotheses of the relationships among amphitritine genera. The large number of homoplasies indicated by the analysis emphasizes the need to further evaluate these hypotheses using additional characters. With a robust phylogenetic hypothesis of amphitritine relationships, a re-classification of the group based on apomorphic character states can be undertaken, and questions regarding the evolution of morphological characters, reproductive modes, or biogeographical patterns can be properly addressed.

Lysippe nikiti n. sp. is described from abyssal depths in the North Pacific and Indian Oceans. It differs from other species of the genus in that it has 14 thoracic uncinigers, ten abdominal uncinigers and three pairs of branchiae. The generic diagnosis is emended to include the newly described fully retractable nuchal organs of the type species L. labiata and details of the position of the nephridiopores. The validity of Samytha is discussed and it is proposed that this genus be treated as junior synonym of Lysippe . Of the 22 species described as Lysippe or its junior synonyms, eight: L. agulhasensis, L. capensis, L. vanelli— type species of Eclysippe, Samytha bioculata— type species of Mooresamytha , S. (?) heterobranchia , S. oculata , S. pallescens— type species of Glyphanostomum and S. (?) speculatrix— have been or should, for reasons discussed here, be transferred to other genera. Neither the original description nor later redescriptions allow differentiation of Samytha californiensis from L. gurjanovae . Thus Lysippe currently includes 13 valid species: L. annectens— type species of Paralysippe , L. annenkovae, L. caeca , L. fragilis— type species of Lysippides, L. gurjanovae, L. hesslei, L. labiata, L. mexicana— type species of Pseudampharete, L. nikiti, L. nipponica , L. sexcirrata, L. storchi and L. trichobranchia .

Biogeographia vol. XXIV — 2003 (Printed October, 31st 2003) Marine biogeography of the Mediterranean Sea: patterns and dynamics of biodiversity Distribution of benthic polychaetous annelids in the Adriatic Sea with zoogeographic considerations GRAZIA CAN TONE Dipzzrzinzmto di Biologizz Animzzle qll/[zzrce/[0 La Greta ” Via Arzdrone 8], 1395124 Camnizz (Italy) e—mzzz'[: czziztogm @um'ct. it Key words: biodiversity, biogeography, Polycltaeta, Adriatic Sea, Mediterranean Sea. SUMMARY Purpose of this paper is to estimate the biodiversity oFtl1e benthic Polychaeta along the Adriatic Sea and to discuss their biogeographical distribution. It is shown that from this sea 580 species, belonging to 57 families, have been so far reported: 401 from the northern Adriatic, 373 from the Central Adriatic, 332 from the southern Adriatic. The dominant biogeogrziphical group is constituted by the Atlantic-Mediterranean species, but well represented are also the cosmopolitan and the endemic ones. T he same pattern is present in all the latitudinal sectors of Adriatic, with little differences in the frequencies of the various categories. INTRODUCTION Differently from the biogeography of terrestrial animals that is known long since, the studies on the distribution of marine fauna and the definition of zoogeographical areas for the marine species are still insufficient. In fact for long it has been a widespread belief, because of the continuity of the water, that marine organisms were cosmopolitan. Many famous polychaetologists, (Fauvel, 1923, 1927; Rullier, 1958; Day, 1967) had the same conviction. I-Iolthe, 1978, in his study on the zoogeography of the Terebellomorpha of the Northern European waters, showed that despite of the tendency towards widespread geographical distribution and eurybathy within this class of Annelids, Polychaeta can contribute to the understanding of marine zoogeography. Recently some scientists have been engaged in clarifying the problem of the wide distribution of this taxon that, according to Fauchald, 1984, might depend on its ancient origin, estimated going back to the Precambrian. The “cosmopolitan” species in many cases are complexes of species with different geographic distribution (\Williams, 1984; Hartley, 1984; Dauvin and Thiebaut, 1994) or “sibling” species

A world catalogue of the subfamily Trichobranchinae (Polychaeta: Terebellidae) is provided. Four genera and 58 species are listed, with references to original descriptions, location of types, type locality, and subsequent taxonomic and applied literature.

Based mainly on the authors' own material from north and central Norway, and on the Ymer expedition material from the Arctic, descriptions of the five Arctic and Scandinavian species of the family Oweniidae, including scanning electron micrographs of chaetae are given, together with the distributions of the species. One new species from the Norwegian Sea and the Arctic is described. A key to the Arctic and Scandinavian species is given. The zoogeography of the Scandinavian and Arctic species is discussed. The position of Boguea Hartman, 1945 and Boguella Hartman & Fauchald, 1971, originally referred to the family Oweniidae, is discussed, and it is concluded that the closest relatives of the bogueids should be sought within the Maldanidae and not within the Terebellomorpha. Mainly on the basis of the appearance and presumed evolution of the ventral chaetae the phylogeny of the four oweniid genera currently considered valid is discussed.

Terebellomorph polychaetes from four Norwegian cruises to the Norwegian Sea and the Swedish Ymer Expedition in 1980 to the deep Polar Sea are treated. A total of 37 species were encountered. One new genus and two new species are described. Mugga bathyalis is a deep-sea species morphologically very close to its shallow-water congener M. wahrbergi ELIASON, 1955. Ymerana pteropoda has like some other ampharetids wing-like parapodia at the transition from thorax to abdomen, but cannot be classified within any of the known genera.

The 70 species of terebellomorph polychaetes of Iceland, north-east Greenland, Spitzbergen, the Barents Sea, the Norwegian Sea, Scandinavian waters, the North Sea, and the Baltic are grouped according to their distribution inside and outside the area under discussion. Their distribution is then used to characterize the different parts of the area. The number of species is small in the deep basins and moderate on the shelf, reaching a maximum in the coastal areas and thereafter decreasing in fjord and estuary systems. There is a more or less ubiquitous ‘arctic’ element in the fauna that dominates the deep sea and the shallow land-locked basins, whereas a ‘non-arctic’ element penetrates far north in coastal and fjord areas. When the fauna is compared with those of other areas, similarity is greater with the Arctic-Pacific then with the Atlantic at comparable distances.

The genus Artacamella was originally described as a member of the Artacaminae within the Terebellidae. A comparison with the genera Artacama Malmgren, 1865 and Trichobranchus Malmgren, 1865 reveals strong affinities of Artacamella to the latter genus. It is proposed that Artacamella should be moved to the Trichobranchidae.

A modified type of kinocilia has been found in the Aulophora-Iarva of the sedentarian polychaete Lanice conchilega. For this newly described cilium type the term "discocilium" is proposed. The only structural difference from usual locomotory cilia is the tip, which possesses a discoidal head. The head is formed from the terminal part of the cilium shaft, which is bent to give rise to a loop-like ring covered by the ciliary membrane. Three types of discocilia can be distinguished: a) discocilia having swollen, bulblike heads with a central straight axoneme; b) discocilia having heads with a curved lateral axoneme and c) discocilia in which the axoneme forms a loop. The internal structure shows the usual 9 + 2 arrangement of the filaments. The head shows no sign of secretion; it appears structureless in electron microscopical examination. There are two kinds of discocilia arrangements: 1) isolated bunches of cilia especially at the tentacles and in the frontal region, and 2) segmental dorsal rows of cilia. The possible formation of discocilia is described.