Ernest R. Schockaert

The importance of turbellarians in the marine meiobenthos: a review

Recent data and opinions on meiofaunal ecology are briefly reviewed; and from scattered data, the place of turbellarians in the meiobenthic community is discussed. Turbellarian diversity, density, and biomass are higher in sandy habitats than in muddy bottoms. In sand, turbellarian diversity is of the same magnitude as that of other important meiofaunal taxa, while densities range between 7–25% of the total meiofauna. Mean individual turbellarian dry weight seems to be four times that of nematodes and in sandy habitats turbellarian biomass may be equal to or excede that of nematodes. Most turbellarian species may be considered as predators and in this respect may take the place occupied by macrofaunal species in muddy sediments. mens.

Filling a gap in the phylogeny of flatworms: relationships within the Rhabdocoela (Platyhelminthes), inferred from 18S ribosomal DNA sequences

The phylogeny of the Rhabdocoela, a species‐rich taxon of free‐living flatworms, is reconstructed based on complete 18S rDNA sequences. The analysis includes 62 rhabdocoels and 102 representatives of all major flatworm taxa. In total, 46 new sequences are used, 41 of them from rhabdocoel species, five from proseriates. Phylogenetic analysis was performed using maximum parsimony and Bayesian inference. Clade support was evaluated with parsimony jackknifing, Bremer support indices and Bayesian posterior probabilities. The resulting cladogram corroborates that the Rhabdocoela is monophyletic, but its sister group remains uncertain. The ‘Dalyellioida’ and the ‘Typhloplanoida’, both former rhabdocoel subtaxa, are polyphyletic. Within the Rhabdocoela the monophyletic Kalyptorhynchia, characterized by a muscular proboscis, forms the sister group of all other rhabdocoels. The Schizorhynchia is a monophyletic subtaxon of the Kalyptorhynchia, with the split proboscis as a synapomorphy. Except for the Dalyelliidae and the Typhloplanidae, both freshwater taxa, none of the ‘families’ previously included in the ‘Typhloplanoida’ and the ‘Dalyellioida’ appears to be monophyletic. As a result of this analysis, three existing and four new taxon names are formally defined following the rules of the Phylocode.

Global diversity of free living flatworms (Platyhelminthes, "Turbellaria") in freshwater

This contribution reviews diversity of turbellarian species by biogeographical regions, with comments on species biology. The review draws on the database available at http://www.devbio.umesci.maine.edu/styler/turbellaria. Comparisons between regions suggest that species richness may be at least one order of magnitude higher than the currently reported number of species. In the context of the recent reconstructions of phylogeny of Platyhelminthes based on molecular data, the paper allows inferences as to the history of colonization of freshwaters by turbellarians. Specifically, four, or perhaps six, major invasions of freshwater habitats may have occurred in the Pangean period, each of which gave rise to a monophyletic freshwater taxon. In addition, several occasional invasions by representatives of marine taxa must have taken place.

Sand dwelling Turbellaria from the Netherlands Delta area

Sand dwelling Turbellaria from the Delta of the Rivers Rhine, Meuse and Scheldt have been investigated. Thirty-eight samples taken from littoral and sublittoral stations in the Grevelingen, Eastern and Western Scheldt have been analysed.

Interstitial fauna of the Galapagos: Duplacrorhynchinae, Macrorhynchinae, Polycystidinae, Gyratricinae (Platyhelminthes Polycystididae)

Seven species from the Galapagos of different subfamilies of the Polycystididae are described and discussed. Four of them are new to science, three of which belong to the subfamily Duplacrorhynchinae Schockaert & Karling 1970: Djeziraia incana n. sp. differs from the other species of the genus by its long, thin stylet; Phonorhynchoides haegheni n. sp. is unique within the genus, as the prostate stylet is much shorter than the accessory stylet; Parachrorhynchus jondelii n. sp. is characterised by the presence of a bundle of atrial glands, paired seminal vesicles, a very large sphincter at the distal end of the female duct, and a ring of hard plates at the distal end of each ovary. of the Macrorhynchinae Evdonin 1977, Macrorhynchus manusferrea n. sp. differs from the other species of the genus by the shape of the stylet and the presence of a female bursa. The subfamily Polycystidinae Schockaert & Karling 1970 is represented by Polycystis ali Schockaert 1982 and Paulodora felis (Marcus 1954). The Galapagos population of the latter species is considered a separate subspecies, P. felis asymmetrica n. subsp., based on differences in the female system. Finally, Gyratrix hermaphro- ditus Ehrenberg 1831 is discussed. Three colour variants of this species complex are found in the Galapagos, which represent three more species in the complex. For all new taxa, a diagnosis is given. At the end, we provide a species list of the polycystidid fauna of the Galapagos Isles.

Spermiogenesis and Sperm Ultrastructure in Thylacorhynchus ambronensis (Schizorhynchia, Kalyptorhynchia, Platyhelminthes)

LIMBURGS UNIV CTR,DEPT SBG,B-3590 DIEPENBEEK,BELGIUM.Watson, NA, UNIV NEW ENGLAND,DEPT ZOOL,ARMIDALE,NSW 2351,AUSTRALIA.

Primary Homology Assessment in the Male Atrial System of the Polycystididae (Platyhelminthes: Eukalyptorhynchia)

Abstract A comparative lightmicroscopical study of the male atrial system of the Polycystididae is presented. Firstly, the different glandular structures associated with the male atrial system are compared. This has lead to the recognition of eight different types of glandular vesicles, four of which are considered prostate, the other four accessory. Secondly, the different hard structures that can be found in the male atrium are discussed and compared. These hard structures can consist of numerous hard spines (armed cirrus), but mostly the hard structure is a single- or double-walled tubiform stylet, or a plate-shaped stylet. Different types of stylets can be recognised, some of which are associated with a prostate vesicle and therefore considered prostate stylets. Using the criteria of position and conjunction, conjectures of homologies are put forward. These primary homologies are compared with homology assessments found in earlier literature.

Typhloplanoida (Platyhelminthes, Rhabdocoela) from New Caledonia and eastern Australia, with the description of six new taxa

Abstract Thirteen species of Typhloplanoida from the Australian east coast and New Caledonia are reported, six of them new to science. Three of these new species are representatives of the Promesostomidae: Coronhelmis cuypersi new species, Coronhelmis novaecaledoniae new species, and Kymocarens kanakorum new species. Austradenopharynx reynaertsi new genus and species is a member of the Solenopharyngidae. Two species are placed within the Typhloplanidae: Kaitalugia lydieae new genus and species and K. falcata new species. Furthermore, new localities are given for Messoplana minuta, known from the Weddell Sea, Brinkmanniella palmata, occurring on the North American Pacific coast, the Swedish west coast and in the Black and Mediterranean Seas, Ceratopera axi, a cosmopolitan species, and Vauclusia conica and Pilamonila bimascula, two Australian species. For the sake of completeness, two more species of which insufficient material is available, are mentioned. A complete species list of all marine Typhloplanoida found in the region is given.

Studies on the ultrastructure of the genital organs in Proseriata (Turbellaria): I. Cirrifera aculeata (Ax) (Coelogynoporidae)

The genital organs in adult specimens of Cirrifera aculeata have been studied by transmission electron microscopy. The male copulatory organ is of the conjuncta‐duplex type provided with a spiny cirrus. The structure of the epithelia lining the different parts of the genital organs is described. The cirrus spines and the spines in the genital atrium are shown to be intracellular specializations. The structure and location of the cirrus spines in the Proseriata studied so far are discussed.

Reports on the Free-Living Platyhelminthes from Australia: Typhloplanoida, with the Description of Three New Taxa

Abstract Five typhloplanoids from the Australian East Coast are reported, three of them new to science. Two taxa are members of Promesostomidae: Vauclusia conica n.g. n.sp., characterised by a cone-shaped stylet, the presence of a female bursa and a very long, partially-swollen female duct; Brinkmanniella australiensis n.sp. has a funnel-shaped stylet with a smooth distal tip. Pilamonila bimascula n.g. n.sp. is a representative of the Solenopharyngidae, characterised by a stylet within a cirrus. The known species found are Ceratopera axi and Ptychopera scutulifer.