Thomas Bartolomaeus | Rheinische Friedrich-Wilhelms-Universität Bonn (original) (raw)

Papers by Thomas Bartolomaeus

Until today, only three species of the Psammodrilida are known. All indivi duals of this taxon be... more Until today, only three species of the Psammodrilida are known. All indivi duals of this taxon bear hooked setae aligned in a pair of transversal rows in each abdominal segment. Such setae are also known from other annelids, like

Convolutriloba longifissura nov. spec. was isolated from a sampie of coral debris from the Indone... more Convolutriloba longifissura nov. spec. was isolated from a sampie of coral debris from the Indonesian coast. The animals have a maximum length of 6 mm and belong to the acoel plathelminths. The animals are green with areas of red pigmentation. The green colour is caused by symbiontic algae which belong to the taxon Tetraselmis. The anterior region of the animals is rounded and contains two unpigmented areas, which are presumed to be eyefields. Caudally they bear three lobes. The animals were kept alive at 25° C; at temperatures below 20° C they degenerate. The animals also die within four days, if they are kept in darkness. It is concluded from this observation that they essentially depend on their symbionts. Convolutriloba longifissura reproduces asexually by longitudinal fission. Fisson always starts anteriorly and one eyefield is adopted by each daughter individual. Although fisson occurs along the median longitudinal axis of the animal, the caudallobes are inequally divided, so that one of the daughter individuals retains one, the other one two lobes. The internaiorgans are completed during fission (architomy) and the new individuals soon acquire the same size as the mother individual. Convolutriloba longifissura is the first record of a plathelminth with longitudinal fission and even within the Bilateria this mode of fission has thus far been unknown for vagile organisms.

Annelids, sipunculids and echiurids possess endothelially lined secondary body cavities, the coel... more Annelids, sipunculids and echiurids possess endothelially lined secondary body cavities, the coelom. The lining of this cavity consists of epithelio-muscle cells, peritoneal cells and podocytes. An investigation of the annelids Eulalia viridis, Harmothoe sarsi, Pholoe inornata, Tomopteris helgolandica, Nereis pelagica, Diplocirrus glaucus, Sternaspis scutata, Scolelepis squamata, Pygospio elegans, Pectinaria koreni, Ophelia rathkei, Spirorbis spirorbis, and Fabricia sabella, the sipunculid Phascolion strombi, and the echiurid Echiurus echiurus reveals that these cells are heterogeneously distributed in the coelomic lining. The visceral coelomic lining of all species consists of a myoepithelium which also consitutes the visceral muscular system. This myoepithelium consists of epithelio-muscle cells and peritoneal cells. The somatic coelomic lining is a myoepithelium in Scolelepis squamata and in Pygospio elegans which also forms the somatic muscular system, whereas a peritoneum lines the somatic muscular system in Harmothoe sarsi, Sternaspis scutata, Pectinaria koreni, Phascolion strombi and Echiurus echiurus. The organization of the coelomic lining varies in the remaining species, even within a single animal. In all species, the mesenteries and dissepiments consist of a double layer of epithelio-muscular cells which rest on an extracellular matrix.

Five day old larvae of Autolytus proliforpossess one pair of anteriorly located protonephridia. E... more Five day old larvae of Autolytus proliforpossess one pair of anteriorly located protonephridia. Each organ consists of one terminal cell, two duct cells and a nephropore cell. The protonephridial cells are multiciliated and the cilia of the terminal cells have no rootlets. The presumed filtration area of the terminal cell consist of six cilia, which each are surrounded by ten microvilli. These microvilli are supposed to represent the supporting structure of a filtration barrier. An extracellular matrix only imcompletely separates the terminal cell and duct cells from the cells of the body wall muscles. The intraepidermal nephropore cell is connected to the adjacent epidermal cells by adhaerens junctions. Within the annelids, mono-or multiciliated protonephridial terminal cells which have no filter, have solely been described for some taxa of the Phyllodocida. The following hypotheses are based on these results: (1) The reduction of the filter, which is the primary supporting structure of the filtration barrier in annelids, and the adoption of its function by microvilli are supposed to be an autapomorphy of a special taxon within the Phyllodocida. (2) Within this special taxon, multiciliarity of the terminal cell characterizes a further monophyletic group, because monociliarity of the terminal cell is presumed to be a plesiomorphic characteristic.

Zoologischer Anzeiger - A Journal of Comparative Zoology

The renopericardial complex of the Mollusca consists of an endothelially lined pericardium which ... more The renopericardial complex of the Mollusca consists of an endothelially lined pericardium which encloses the heart, and a pair of excretory renopericardial ducts. The heart represents a primary body cavity and the pericardium a secondary body cavity or coelomic cavity. In order to study this complex in an opisthobranch gastro pod and to obtain data for a comparison of excretory organs and coelomic cavities between molluscs and annelids, the interstitial gastropod Philinoglossa helgolandica Hertling, 1932 was investigated ultrastructurally. The lens shaped pericardium lies dorso-laterally between the midgut gland and the epidermis and is surrounded by an extra cellular matrix (ECM) and muscle cells. The epicardium of the ventricle and the auricle consists of epithelio-mus cle cells, while the side of the pericardium facing the kidney is predominant lined with podocyte-like cells. These cells are presumed to allow an ultrafiltration of blood fluid into the pericardium. The remaining pericardial surface is lined with non-muscular cells. The renopericardial ducts consist of a ciliated proximal section and a distal aciliated section. The cells of the latter section have enlarged basal and apical surfaces and morphologically reveal transcytotic activity. The nephropore lies ventro-laterally. A comparision of the molluscan renopericardial complex with the coelom and the nephridia of the annelids reveals that the pericardium and the renopericardial ducts must have evolved in the stem lineage of the Mollusca and, thus, represent an autapomorphy of this taxon.

CFS Courier Forschungsinstitut Senckenberg

Die Arenicolidae umfassen 22 Arten, die sich auf die Taxa Branchiomaldane LANGERHANS, 1881, Areni... more Die Arenicolidae umfassen 22 Arten, die sich auf die Taxa Branchiomaldane LANGERHANS, 1881, Arenicolides MESNIL, 1898, Abarenicola WELLS, 1959, und Arenicola LAMARCK, 1801 verteilen. Fast alle Arten sind Sedimentfresser; die der bei den letztgenannten Taxa leben welt weit in Sandwatten in selbstgegrabenen Bauten. Die Arenicolidae sind die Schwestergruppe der ebenfalls sedimentfressenden Maldaniden. Nach der vorliegenden Analyse bilden Branchiomaldane und die Arenicolinae die ranghöchsten Taxa der Arenicolidae, innerhalb der Arenicolinae sind Arenicolides und die Caudata ranghöchste Schwestergruppen. Die Caudata umfassen die Taxa Abarenicola und Arenicola, deren Arten durchgehend einen borsten-und kiemenlosen Schwanzanhang aufweisen. Dieser Anhang stellt die Autapo morphie der Caudata dar; seine Evolution läßt sich als Adaptation auf den hohen Räuberdruck in Sandwatten interpretieren. Abstract The Arenicolidae consists of 22 species, which belong to four different monophyletic taxa, Branchiomaldane LANGERHANS, 1881, Arenicolides MESNIL, 1898, Abarenicola WELLS, 1959, and Arenicola LAMARCK, 1801. All species of the three latter taxa are sediment feeders, live in burrows and mostly inhabit the intertidal sand flats of the world. The present phylogenetic analysis based on studies of chaetation and literature data results in the hypoth esis that Arenicola and Abarenicola are sister groups forming the taxon Caudata. The si ster taxon of the Caudata is Arenicolides, together representing the taxon Arenicolinae. Finally, the highest ranking taxa within the Arenicolidae are Branchiomaldane and Arenicolinae. The Maldanidae is the si ster taxon of the Arenicolidae due to a unique inverted position of the neuropodial site of setal formation. Evolutionary considerations based on this hypothesis lead to the assumption that an abranchiate tail evolved in the stem lineage of the Caudata as an adaptation to high predatorary pressure in sand flats.

Different epi thelia of the suspension feeding hemichordate Rhabdopleura compacta have been studi... more Different epi thelia of the suspension feeding hemichordate Rhabdopleura compacta have been studied ultrastructurally. The epidermis is mainly monociliate, though biciliate cells occur also. CiHa are found in all epithelia, but not every cell bears a cilium. Differences between ciliary basal structures are apparent. In general, four types can be differentiated which are characterized (1) by the absence of any cross-striated rootlet, by the presence of (2) only one vertical rootlet, (3) two vertical rootlets, and (4) a vertical and a horizontal rootlet. Each type of ciliary basal structures is related to certain epitheHa. The distinct distribution of cross-striated ciliary rootlets to different epithelia seems, thus far, to be unique among metazoans.

The contradictory understanding of the molluscan organization, i.e., its having evolved from a me... more The contradictory understanding of the molluscan organization, i.e., its having evolved from a mesenchymate configuration or from organisms with a body-coelom/secondary body cavity, is reevaluated according to organogenetic and fine-structural data of the (gono-)pericardium. The different configurations of body cavities at the ultrastructural and developmental levels in Gastroneuralia are outlined and compared with the condition in Mollusca. This reveals that the gonopericardial complex is differentiated in addition to the musculature (myoblastema), whereas the secondary body cavity in actual coelomates is part of their myoblastema-differentiation. In addition to. earlier argumentation by different Authors with respect to comparative anatomy, developmental patterns and functional correlations, the formation and structure of the (gono-)pericardium thus fully supports the diphyletic differentiation of the mesothelially-lined cavities (mesothelocoelia) in Mollusca and organisms with a...

BMC Biology

A response to Ziegler A, Faber C, Mueller S, Bartolomaeus T: Systematic comparison and reconstruc... more A response to Ziegler A, Faber C, Mueller S, Bartolomaeus T: Systematic comparison and reconstruction of sea urchin (Echinoidea) internal anatomy: a novel approach using magnetic resonance imaging.

The growing success of molecular methods has challenged traditional views of animal evolution and... more The growing success of molecular methods has challenged traditional views of animal evolution and a large number of alternative hypotheses are hotly debated today. For the deep metazoan phylogeny project, data sets of hitherto unmatched quality and quantity were compiled and analysed with innovative bioinformatics tools. The book begins at the base of the tree of life to discuss the origin of animals and early branches of the phylogenetic tree. The following section presents special data sets gained from mitochondrial genomes and from morphology, with a focus on nervous systems. The final section is dedicated to theoretical aspects of data analysis and new bioinformatics tools. The book closes with a unique general discussion of all hypotheses contained in previous chapters.This work provides the most comprehensiveoverview available of the state of the art in this exciting field of evolutionary research.

Modern microscopical methods like µCT, FIB, and cLSM have almost replaced traditional histology i... more Modern microscopical methods like µCT, FIB, and cLSM have almost replaced traditional histology in the comparative study of animal anatomy. The main advantage of these modern methods is the provision of volume data that represent anatomical structures in their original arrangement and thus enable automated image processing for anatomical 3D reconstruction. Histology on the other hand provides a higher resolution at cellular level and profoundly eases unambiguous interpretation of the data due to differential, tissue specific stains. .Yet, the use of serial section histology for 3D reconstruction underlay three drawbacks: 1) Image data must be acquired section by section and transformed into an aligned image stack. 2) Structure labeling in terms of segmentation of images cannot be automated. 3) High resolution image stacks comprise several gigabytes of data and thus are difficult to handle by software for processing and publication. The latter impedes sharing of original data sets an...

Naturwissenschaftliche Rundschau

Reproductive Strategies and Developmental Patterns in Annelids, 1999

In Annelida, nearly each segment contains a pair of ducts that either are protonephridia or metan... more In Annelida, nearly each segment contains a pair of ducts that either are protonephridia or metanephridia. These segmental organs function as excretory organs and, after having been modified, they may also act as gonoducts during maturity. In certain polychaetous annelids and especially in clitellates this function has been adopted by additional gonoducts which generally are formed at the begining of maturity. At the end of the last century the gonocoel theory tried to explain the relation between gonads, coelomic cavities and nephridia. Using the gonocoel theory axiomatically, assumed that in annelids a pair of protonephridia and a pair of gonoducts represent the primary condition. Evolution of metanephridia on the one hand and the fusion of gonoducts and nephridia on the other hand occurred within the Annelida. Based on recent ultrastructural investigations into the development of different segmental organs, this paper re-evaluates Goodrich's hypothesis. According to these data the segmental organs differentiate from a single anlage. Each consists of three or four cells which line a small lumen filled with microvilli. The duct becomes ciliated and the most proximal cells are separated when the coelom extends by fluid accumulation between the lining cells. During enlargement of the coelomic cavity the proximal part of the anlage is passively opened, so that the cilia face the coelom, to form the funnel. If separation of the proximal duct cells is suppressed, the anlage differentiates into a protonephridium, which secondarily may acquire a funnel during maturity by proliferation of proximal duct cells. Thus, different pathways in nephridial development lead to completely different segmental organs in the fertile adult. Additional gonoducts evolve in different lineages within the annelids.

Biologie in unserer Zeit, 1995

Gut 35 Jahre sind seit der ersten elektronenoptischen Beschreibung von Protonephridien durch Kümm... more Gut 35 Jahre sind seit der ersten elektronenoptischen Beschreibung von Protonephridien durch Kümmel vergangen. In den letzten Jahren haben sich für diese Nierenorgane Struktur-Funktions-Beziehungen heraus kristallisiert, die zu einem sehr soliden Bild von den vielzelligen Exkretionsorganen bei Wirbeltieren und deren Evolution führen.

Developments in Hydrobiology, 2005

Proceedings of the 12th International Echinoderm Conference, 7-11 August 2006, Durham, New Hampshire, U.S.A., 2009

ABSTRACT Histological analyses of sea urchins (Echinoidea) confront the researcher with a number ... more ABSTRACT Histological analyses of sea urchins (Echinoidea) confront the researcher with a number of problems such as compression and deformation of the object. In addition, the process is time-consuming and irretrievably alters the specimen. In our study we show that in vitro non-invasive analyses using Magnetic Resonance Imaging (MRI) are feasible for sea urchins and yield data that can be easily used for three-dimensional (3D) reconstruction of soft- and hard-part anatomy. With the achieved isotropic resolution of 117μm, gross anatomical features such as gonads, digestive tract, Aristotle’s lantern, calcite endoskeleton, and even mesenteries can be identified.We propose a number of applications for further studies involving sea urchins and MRI.

In Annelida, nearly each segment contains a pair of ducts that either are protonephridia or metan... more In Annelida, nearly each segment contains a pair of ducts that either are protonephridia or metanephridia. These segmental organs function as excretory organs and, after having been modified, they may also act as gonoducts during maturity. In certain polychaetous annelids and especially in clitellates this function has been adopted by additional gonoducts which generally are formed at the begining of maturity. At the end of the last century the gonocoel theory tried to explain the relation between gonads, coelomic cavities and nephridia. Using the gonocoel theory axiomatically, Goodrich (1945) assumed that in annelids a pair of proto nephridia and a pair of gonoducts represent the primary condition. Evolution of metanephridia on the one hand and the fusion of gonoducts and nephridia on the other hand occurred within the Annelida. Based on recent ultrastructural investigations into the development of different segmental organs, this paper re-evaluates Goodrich's hypothesis. According to these data the segmental organs differentiate from a single anlage. Each consists of three or four cells which line a small lumen filled with microvilli. The duct becomes ciliated and the most proximal cells are separated when the coelom extends by fluid accumulation between the lining cells. During enlargement of the coelomic cavity the proximal part of the anlage is passively opened, so that the cilia face the coelom, to form the funnel. If separation of the proximal duct cells is suppressed, the anlage differentiates into a protonephridium, which secondarily may acquire a funnel during maturity by proliferation of proximal duct cells. Thus, different pathways in nephridial development lead to completely different segmental organs in the fertile adult. Additional gonoducts evolve in different lineages within the annelids.

Zoologischer Anzeiger - A Journal of Comparative Zoology

CFS Courier Forschungsinstitut Senckenberg

BMC Biology

Naturwissenschaftliche Rundschau

Reproductive Strategies and Developmental Patterns in Annelids, 1999

Biologie in unserer Zeit, 1995

Developments in Hydrobiology, 2005

Proceedings of the 12th International Echinoderm Conference, 7-11 August 2006, Durham, New Hampshire, U.S.A., 2009

In Annelida, nearly each segment contains a pair of ducts that either are protonephridia or metan... more In Annelida, nearly each segment contains a pair of ducts that either are protonephridia or metanephridia. These segmental organs function as excretory organs and, after having been modified, they may also act as gonoducts during maturity. In certain polychaetous annelids and especially in clitellates this function has been adopted by additional gonoducts which generally are formed at the begining of maturity. At the end of the last century the gonocoel theory tried to explain the relation between gonads, coelomic cavities and nephridia. Using the gonocoel theory axiomatically, Goodrich (1945) assumed that in annelids a pair of proto nephridia and a pair of gonoducts represent the primary condition. Evolution of metanephridia on the one hand and the fusion of gonoducts and nephridia on the other hand occurred within the Annelida. Based on recent ultrastructural investigations into the development of different segmental organs, this paper re-evaluates Goodrich's hypothesis. According to these data the segmental organs differentiate from a single anlage. Each consists of three or four cells which line a small lumen filled with microvilli. The duct becomes ciliated and the most proximal cells are separated when the coelom extends by fluid accumulation between the lining cells. During enlargement of the coelomic cavity the proximal part of the anlage is passively opened, so that the cilia face the coelom, to form the funnel. If separation of the proximal duct cells is suppressed, the anlage differentiates into a protonephridium, which secondarily may acquire a funnel during maturity by proliferation of proximal duct cells. Thus, different pathways in nephridial development lead to completely different segmental organs in the fertile adult. Additional gonoducts evolve in different lineages within the annelids.