Bryozoology

Vorstellung des Dissertations-Themas Vorläufiger Arbeitstitel: "Die Anasca (Bryozoa: Cheilostomata) des österreichischen Neogen -eine Revision". Systematische Durchsicht von Sammlungsmaterial (UDIN, BOBIES, SCHMID, VÁVRA), Neuaufsammlungen (Nußdorf, Kalksburg, St. Margarethen -Kogel, Oslip, Eisenstadt-Hartl, u.a.m.) Möglichst genaue Erfassung der Morphologie, Vergleich mit Rezentmaterial. Bearbeitung einiger besonders "neuralgischer Punkte" ("Membranipora" im Tertiär, Cellaria-Arten, u.s.w). "Nussdorf [...] sey ein sehr schönes, großes und wohlgebautes Dorff an der Donau gelegen, welches das Ansehen eines kleinen Städtchens hat und wegen der lustigen und angenehmen Lage zu schätzen ist. Denn auf der einen Seite sieht man nichts als Weinberge und auf der anderen fliesset der verbreitete Donaustrom vorbey. [...] Überdies wird es auch von vielen [Leuten] die sich zerstreuen wollen, besucht und werden allhier die kostbarsten Schmausereyen gegeben und Sonntag laufft jedermann vollends hinaus, um sich zu erlustigen und einen guten Rausch zu holen." Ein Besucher von Nußdorf im späten 18. Jahrhundert.

The transition from uniserial to multiserial forms in the evolution of the bryozoan order Cheilostomata resulted from the change from a proxipetal sequence of development of buds in zooids to a distopetal. Possible morphogenetic mechanisms of this transformation are discussed.

Short overview of published data concerning the marineand freshwater bryofauna from the Baltic Sea area with focus on their history,ecology, distribution, species list and taxonomy. More than 140 years history ofthe Baltic Sea studies recorded in the literature were reviewed, and comparedwith results of our actual research conducted during 2001-2004 in Kiel Bay. One species of marine bryozoans – Electra arctica – was first documented inthe Baltic Sea. Some main features of the Baltic bryozoan fauna such asfluctuating occurrences of species in response to oscillations in thehydrographic regime of the Baltic Sea and its open character in respect toKattegat populations are discussed.

B.C. Dumortier, a pioneer of bryozoology. — The publications of Pierre-Joseph Van Beneden. — Dumortier and Van Beneden as joint authors. — Biographical sketch of B.C. Dumortier. —  Biographical sketch of P.-J. Van Beneden. —  Henri Milne-Edwards, a Frenchman bom in Belgium. —  Remarks conceming Gérard-Daniel Westendorp. — Karel Loppens and his research on bryozoans. — Biography of Karel Loppens. — Paul Brien's work on bryozoans. — Biography of Paul Brien. — A.W. Lacourt and the Belgian bryozoans. — Bryozoan studies in the Grand Duchy of Luxembourg.

In 1931, Borg distinguished five ‘‘varieties’’ as morphologically differing from what he perceived as the ‘typical form’ of Electra crustulenta (Pallas, 1766). Taxonomic status has not been resolved for all of those morphotypes. One of them was recently recognized as a separate species, E. arctica; two are considered as species in other genera. In the present study the remaining three of Borg’s subdivisions, ‘‘forma typica’’, ‘‘var. baltica’’ and ‘‘var. fossaria’’, were analyzed to evaluate their status and reconstruct phylogenetic relationships within the whole species group based on ribosomal 16S
mtDNA and 18S nDNA. All known E. crustulenta-like species and forms with unresolved status were included: E. crustulenta (including ‘‘f. typica’’, ‘‘var. baltica’’ and ‘‘var. fossaria’’), E. arctica, E. korobokkura, and Electra moskvikvendi sp. nov. A well-supported phylogeny fully concordant for both genetic markers was obtained with maximum parsimony, neighbor-joining, maximum likelihood, and Bayesian methods. Statistical parsimony was applied to the 16S dataset. Only four species were revealed regardless of the method or gene fragment, with E. crustulenta as a single species. There was no evident correlation between the morphotypes ‘‘f. typica’’, ‘‘var. baltica’’ and ‘‘var. fossaria’’ and haplogroups found in E. crustulenta populations. The E. crustulenta species group consisted of two subgroups: E. crustulenta–E. korobokkura and E. moskvikvendi–E. arctica. Divergence of the mitochondrial lineages within the group was dated using a Bayesian relaxed-clock approach. Most probably the diversification of the lineages examined started in the Early Miocene. Electra arctica and E. moskvikvendi sp. nov. are two young species, having diverged during the Pliocene–Pleistocene. The new species described here was found in the Western Baltic Sea, Kiel Bay. An identification key for the E. crustulenta species group is given, based on morphology, morphometry, and geographical and ecological ranges. Additionally, reference sequences of 16S and 18S DNA for each species, which can be used for DNA-based barcoding, have been published.

The first freshwater bryozoan was described from the Netherlands in 1744 by Abraham Trembley, but in Luxembourg the history of freshwater bryozoology only begins in 1901 with a colony of Plumatella fungosa found by the physician Eugène Bricher (1875- 1937). In 1956, Cristatella mucedo was recorded by professor Jos Hoffmann (1911-2000). A hydrobiological study made in 1958/1959 by the German hydrobiologist Erik Mauch showed the occurrence of Fredericella sultana, P. fungosa and P. emarginata in the river Moselle. In 1975 the scientific dissertation of Gaby (Gabrielle) Geimer, the first exhaustive study of the bryozoan fauna of Luxembourg, added Paludicella articulata, Plumatella repens, P. fruticosa and Hyalinella punctata to the list. In 1986 Gaby Geimer and Jos Massard published their monograph ‘Les Bryozoaires du Grand-Duché de Luxembourg et des régions limitrophes’ in which the occurrence of Plumatella casmiana in Luxembourg was recorded. In 2012 Pectinatella magnifica, hitherto only known by statoblasts found in 2001 near the German-Luxembourg border on German territory, has been recorded in the reservoir of Esch-sur- Sûre situated in the northern part of Luxembourg. Thus, presently, nine phylactolaemate and one gymnolaemate species are known from the Grand-Duchy, a total of ten bryozoan species. Lophopus crystallinus remains to be found.

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Electra crustulenta var. arctica can form two kinds of growth: incrusting (prevailed) form and erect form. Mechanical obstacles for an attachment of buds to substratum is one of the reasons of formation of erect series of tubular zooids. The growing tip of a chain can be attached, that results іп development of usual zooids and formation of new incrusting colonies. The contact of buds with substratum has the important meaning for zooidal morphogenesis.

The substrate dependence of growth and development of the buds in bryozoans, which has been known for a long time, remains little studied. Classification of the substrate reactions of buds, which can be distinguished at the macro-morphological level , has shown that each species has a limited set of ways of "substrate reaction," which are correlated with a certain type of three-dimensional colony organization. When the "normal" shape of buds is disturbed by external factors, there are some feature s of deviation of the morphological and histological differentiation of the ectodermal epithelium and its derivative from the normal condition. It has been proposed that these processes depend on the external bud shape, which depends, in turn, on attachment to the substrate (the bud is spread during attachment).