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  • 1
    Electronic Resource
    Electronic Resource
    Ultrastruktur potentiell photoreceptorischer Zellen unterschiedlicher Organisation bei einem Proseriat (Plathelminthes) (1982)
    Springer
    Zoomorphology 101 (1982), S. 165-175 
    Details
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Zwei links und rechts im Vorderkörper von Cirrifera aculeata (Ax, 1951) (Proseriata) gelegene Zellen werden als mögliche Photoreceptoren angesprochen. In ein großes intracelluläres Lumen der linken Zelle ragen über 70 nur leicht modifizierte Cilien, daneben treten Mikrovilli und elektronendichte Granula auf. Die vermutlich lichtsensitiven Strukturen der rechten Zelle bilden dicht nebeneinander liegende röhrenartige Vakuolen, vergleichbar den Mikrovilli eines Rhabdoms. Die funktionellen und evolutiven Aspekte dieser beiden bisher unbekannten Zelltypen werden diskutiert.
    Notes: Summary Two cells which lie at the left and at the right near the anterior end of Cirrifera aculeata (Ax, 1951) (Proseriata) are interpreted as presumed photoreceptors. In the left cell up to 70 slightly modified cilia extend into a large intracellular cavity. Besides these cilia microvilli and electron-dense granules are present. The presumed light sensitive structures of the right cell are formed by tubular vacuoles which are arranged without gaps, thus comparable to the microvilli of a rhabdom. The functional and evolutionary aspects of these two cell types are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00312431
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  • 2
    Electronic Resource
    Electronic Resource
    Epidermale Collar-Receptoren der Nematoplanidae und Polystyliphoridae (Plathelminthes, Unguiphora) (1984)
    Springer
    Zoomorphology 104 (1984), S. 226-230 
    Details
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Für die Nematoplanidae und die Polystyliphoridae (Proseriata) wird ein besonderer Collar-Receptor-Typus beschrieben, der vom Grundmuster der entsprechenden Receptoren der übrigen Proseriata und der Rhabdocoela in zwei Punkten abweicht: (1) Die Receptoren ziehen zwischen Epidermiszellen zur Körperoberfläche. (2) Im distalen Bereich der Receptoren ist im Cytoplasma eine elektronendichte Manschette differenziert. — Zusammen mit anderen Organisationsmerkmalen wird die Manschette dieses Receptor-Typus als Synapomorphie der Nematoplanidae und Polystyliphoridae, des monophyletischen Taxon Unguiphora Sopott-Ehlers, 1984, bewertet.
    Notes: Summary In the Nematoplanidae and the Polystyliphoridae (Proseriata) a special collar receptor type is found, which differs in two points from the basic pattern of these receptors in the other Proseriata and in the Rhabdocoela: (1) The receptors run between epidermal cells to the surface. (2) In the distal region of the receptor cells an electron-dense cuff is developed. The cuff of these receptors, together with some other features of organisation, is considered to be a synapomorphy of the Nematoplanidae and the Polystyliphoridae, which together form the monophyletic taxon Unguiphora Sopott-Ehlers, 1984.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00312035
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  • 3
    Electronic Resource
    Electronic Resource
    Ultrastructure of the subepidermal musculature of Xenoturbella bocki, the adelphotaxon of the Bilateria (1997)
    Springer
    Zoomorphology 117 (1997), S. 71-79 
    Details
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Xenoturbella bocki is the only species of the high-ranked taxon Xenoturbellida. The species lives on marine mud bottoms at a depth of 20–120 m and moves extremely slowly by ciliary gliding. Nevertheless it possesses a well-developed body wall musculature with outer circular muscles, a prominent layer of inner longitudinal muscles and radial muscles that extend from the outer circular myocytes to the musculature surrounding the gastrodermis. The longitudinal myocytes are not compact cells, but form fascicles of fibrils running parallel to each other. Fine cytoplasmic cords connect the fibres of a cell to each other and with its nuclear region. The muscles are embedded within a sometimes expansive extracellular matrix (ECM) that lacks any fibrillar components. All muscle cells display conspicuous and numerous cytoplasmic extensions that are intermingled with each other. Tight coupling between adjacent cell membranes is not found, but zonula adhaerens-like junctions exist. Fibrils belonging to different myocytes, but also fibrils of the same cell, are coupled by such cytoplasmic extensions. Circular, radial and at least the peripheral longitudinal myocytes display cell-matrix connections with the internal lamina, a component of the subepidermal ECM. This internal lamina projects down into the centres of the fascicles with longitudinal muscle fibrils and forms extensive attachment zones with the muscle cells, reminiscent of focal contacts. For the ingestion of food, X. bocki opens the simple mouth pore and protrudes the aciliated gastrodermis. The body wall musculature is responsible for this protrusion and also for the withdrawal of the gastrodermis. In the past, possible phylogenetic kinships with the Acoelomorpha (Plathelminthes) or the Enteropneusta and Holothuroidea were discussed, but, on the basis of all information available, X. bocki is hypothesized to be the sister taxon of the Bilateria.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004350050032
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  • 4
    Electronic Resource
    Electronic Resource
    Development and submicroscopic anatomy of male gametes in Halammovortex nigrifrons (Plathelminthes, Rhabdocoela, ”Dalyellioida”): phylogenetic implications and functional aspects (1998)
    Springer
    Zoomorphology 117 (1998), S. 213-222 
    Details
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  The steps of spermiogenesis and the submicroscopic anatomy of male gametes in Halammovortex nigrifrons are described. During spermiogenesis the cytophore develops pseudopod-like extensions, and bung-like deposits of dark material become attached to the basal bodies of the cilia. During the phase of cell elongation, cilia stay near the edge of the cytophore. Spermatozoa bear two free cilia or flagella. The axonemata are equipped with glycogen islets appearing at regular spaces. The sperm body is characterized by dot-like dense granules linearly arranged, intense glycogen aggregations in a channel-shaped deposition and giant dense bodies. Events of spermiogenesis and the features of mature male gametes in H. nigrifrons corroborate the hypothesis of the existence of a monophylum within the Rhabdocoela encompassing several, but not all taxa of the ”Typhloplanoida” and ”Dalyellioida”. The Dalyelliidae (including the species of the Temnocephalida) belong to this monophylum.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004350050046
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  • 5
    Electronic Resource
    Electronic Resource
    Organization of statocysts in the Otoplanidae (Plathelminthes): an ultrastructural analysis with implications for the phylogeny of the Proseriata (1990)
    Springer
    Zoomorphology 109 (1990), S. 309-318 
    Details
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The statocyst of otoplanids is enveloped by a bipartite capsule which consists of two different extracellular matrices. This capsule encircles three different types of aciliary cells: several peripherally located flattened parietal cells, one central statolith forming cell (lithocyte) and two clusters of accessory cells. Intracapsular lumina exist which are different from extracapsular intercellular spaces. The accessory cells most probably represent those structures that are mainly involved in nervous conduction. These cells extend cytoplasmatic processes towards different peripheral regions of the statocyst where processes of outer nerve cells penetrate the capsule. The statocyst does not seem to represent a more evolved equilibrium receptor system but may function as a relatively simple aciliary sense organ suitable for positive geotactic behaviour. The otoplanid statocyst corresponds to statocysts in other lithophorous proseriates but not to statocysts in other taxa of the free-living Plathelminthes. The monophyly of a taxon Lithophora within the Proseriata is corroborated by this autapomorphic characteristic.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00803571
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  • 6
    Electronic Resource
    Electronic Resource
    Monociliary receptors in interstitial Proseriata and Neorhabdocoela (Turbellaria Neoophora) (1977)
    Springer
    Zoomorphology 86 (1977), S. 197-222 
    Details
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The ultrastructure of monociliary receptors in 10 species of the Proseriata and Neorhabdocoela is described, with particular reference to the epidermal dendritic part. Sensory cells with a single kinocilium situated at the level of the distal epidermis membrane are considered as mechano- or chemoreceptors. There exist sensory cells with a dendrite penetrating one epidermis cell and bearing an embedded kinocilium and a collar of 8 stereocilia or ridges with a fribrillose substructure. These collared receptors probably function as mechanoreceptors. In comparison with collared sensory cells in species of other turbellarian orders, the embedded receptors in the Proseriata and Neorhabdocoela are more advanced and possess synapomorphous characteristics. With the embedded receptors a new evidence is given for the close phylogenetic relationship between the Proseriata and Neorhabdocoela. The distribution of collared cells in the animal system and their phylogenetic implication for a choanoflagellate origin of the Metazoa are briefly discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00993666
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  • 7
    Electronic Resource
    Electronic Resource
    Ultrastruktur pericerebraler Cilienaggregate beiDicoelandropora atriopapillata Ax undNotocaryoplanella glandulosa Ax (Turbellaria, Proseriata) (1977)
    Springer
    Zoomorphology 88 (1977), S. 163-174 
    Details
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Die Ultrastruktur pericerebral gelegener Cilienaggregate vonDicoelandropora atriopapillata Ax, 1956, undNotocaryoplanella glandulosa (Ax, 1951) wird beschrieben. Die intracellulÄren Aggregate setzen sich jeweils aus mehreren 100 Cilien zusammen, die lückenlos alternierend angeordnet und distal miteinander verflochten sind. Für die Cilienaggregate wird eine photoreceptorische Funktion wahrscheinlich gemacht.
    Notes: Summary The ultrastructure of pericerebrally located ciliary aggregations inDicoelandropora atriopapillata Ax, 1956, andNotocaryoplanella glandulosa (Ax, 1951) is described. The intracellular aggregations consist of some 100 cilia, which are arranged in an alternating position without gaps. The distal parts of the cilia are interweaved. The aggregations are interpreted as photoreceptors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01880652
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  • 8
    Electronic Resource
    Electronic Resource
    Ultrastructural observations of the spermiogenesis in the Parotoplaninae (Plathelminthes, Proseriata) with special reference to a striated appendage of the intercentriolar body (1993)
    Springer
    Zoomorphology 113 (1993), S. 191-197 
    Details
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The spermiogenesis of three species of the Parotoplaninae (Otoplanidae, Proseriata) is described based on electron-microscopical observations. Special reference is given to organelles which do not persist in mature male gametes. One of these organelles is a striated appendage of the intercentriolar body. This differentiation has not been reported from any other plathelminth taxa up to now. The striated appendage, which may serve as a strengthening element, is hypothesized to be an autapomorphic feature of the Parotoplaninae.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00394859
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  • 9
    Electronic Resource
    Electronic Resource
    Die Feinstruktur der Sehkolben und der Lamellarkörper von Parotoplana capitata (Plathelminthes, Proseriata) (1986)
    Springer
    Zoomorphology 106 (1986), S. 44-48 
    Details
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Summary The ultrastructure of intracerebral visual clubs and the fine structure of presumed photoreceptive lamellate bodies from the cerebral region of Parotoplana capitata are described. The rhabdomeric elements of the visual clubs exhibit a tripartite configuration. Some microvilli are mingled with the cilia of the lamellate bodies. The evolutionary aspects of the visual clubs and of the lamellate bodies are discussed. The absence of pigment granules within the mantle cell of the visual clubs form an autapomorphy of the Proseriata Lithophora. Ciliary lamellate bodies represent an autapomorphy of the subordinated taxon Parotoplaninae.
    Notes: Zusammenfassung Die Ultrastruktur der intracerebralen Sehkolben und die der potentiell photoreceptorischen Lamellarkörper aus der Cerebralregion von Parotoplana capitata werden dargestellt. Die Konfiguration der Rhabdomeren der Sehkolben zeigt eine deutliche Terzettbildung. Zwischen die Cilien der Lamellarkörper schieben sich einige Mikrovilli. Die Bedeutung der pigmentfreien Sehkolben und der Lamellarkörper in evolutiver Hinsicht wird diskutiert. Der Mangel von Pigmentgranula in der Mantelzelle der Sehkolben bildet eine Autapomorphie der Proseriata Lithophora. Ciliäre Lamellarkörper repräsentieren vermutlich eine Autapomorphie des Teiltaxons Parotoplaninae.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00311946
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  • 10
    Electronic Resource
    Electronic Resource
    On the spermiogenesis of Invenusta aestus (Plathelminthes, Proseriata) an ultrastructural study with implications for plathelminth phylogeny (1989)
    Springer
    Zoomorphology 109 (1989), S. 145-152 
    Details
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The spermiogenesis of Invenusta aestus (Coelogynoporidae) is described based on electron microscopical observations. Special attention is paid to the intercentriolar body and the anchoring apparatus of the cilia. These organelles are differentiated at the beginning of spermatid maturation and undergo striking changes during gametogenesis. The importance of the organelles mentioned for discussion of phylogenetic relationships within the Plathelminthes is considered.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00312266
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