Ultrastructural characteristics of the cortex and of the membranelles of the ciliate Espejoia mucicola (Oligohymenophora, Hymenostomata, Tetrahymenina)]

It was shown in a detailed study of the cortex and buccal organelles of Espejoia that, at the ultrastructural level, the general plan of organization of this ciliate conforms to that of Tetrahymenina. Specific variations seen in the cortex and membranelles bring out the very pronounced affinities of Espejoia to the genus Glaucoma and other related ciliates. In view of the foregoing and on the basis of reccent findings on morphogenesis, we confirm the taxonomic position of Espejoia mucicola among Tetrahymenina in the family Glaucomidae.     

A Propos D'observations Sur L'ultrastructure Du Cilié Cyrtolophosis Mucicola Stokes, 1885

RESUME L'étude détaillée du cortex et des organelles buccaux de Cyrtolophosis mucicola montre que ce Cilié possède une organisation structural corticale comparable à celle de Woodruffia, Platyophrya, Kuklikophrya et des Colpoda . Tout en restant conforme au plan général d'organisation de ces derniers, il a des variations spécifiques décelées au niveau des organelles buccaux qui confirment la position de C. mucicola dans la famille des Cyrtolophosididae , incluse dans le sous-ordre des PLATYOPHRYINA.     

Caractéristiques De La Stomatogenèse Et Des Ultrastructures Corticale Et Buccale Du Cilié Colpodidea Bursaria Truncatella O. F. Müller, 1773

RESUME. Chacun des 45–80 organelles adoraux de Bursaria truncatella O. F. Müller est constitué de 3 rangées de cinétosomes et l'aire buccale droite est couverte de nombreuses doubles rangées de cinétosomes. La stomatogenèse débute par la désorganisation et la résorption des organelles buccaux postérieurs. Puis, il y a désorganisation des rangées parorales de cinétosomes et multiplication des cinétosomes sur l'aire orale droite, en měme temps que sont rompues, selon une ligne oblique, un certain nombre de cinéties somatiques. La prolifération des cinétosomes aux extrémités des cinéties. de part et d'autre de la ligne de rupture, aboutit, d'une part, à la formation d'un champ anarchique qui est le primordium oral droit de l'opisthe, d'autre part, à la formation de nombreux doublets qui constituent chacun le primordium de chaque organelle adoral. Après la séparation des tomites, les cinétosomes de l'aire droite s'ordonnent en doubles rangées et les organelles adoraux se complètent par addition d'une 3ème rangée de cinétosomes. Les cinétosomes somatiques sont jumelés, reliés par 2 desmoses. Les fibres transverses postérieures et les fibres postciliaires forment de longs rubans de microtubules dirigés vers l'arrière et juxtaposés dans les crětes intercinétiennes. Les doubles rangées droites de cinétosomes buccaux sont assimilables à des stichodyades. Les organelles des cinétosomes adoraux portent des rideaux de fibres postciliaires convergents ou divergents. La rangée postérieure de chaque organelle est non ciliée. Par son type de stomatogenèse, par sa structure corticale, par l'ultrastructure des organelles adoraux, Bursaria appartient aux Colpodidea, ce qui suggère des remarques de plusieurs types. SYNOPSIS. In Bursaria truncatella O. F. Müller, each of the 45–80 adoral organelles is composed of 3 rows of kinetosomes, and the right buccal area is covered by many double rows of kinetosomes. Stomatogenesis begins by disorganization and disappearance of the posterior buccal organelles. Next, there is disorganization of the paroral rows of kinetosomes and multiplication of kinetosomes in the right oral area; at the same time, some somatic kineties are disrupted along an oblique line. Multiplication of kinetosomes at the extremities of the kineties, on both sides of the disruption, leads to the formation of an anarchic field which is the right oral primordium of the opisthe and the formation of doublets each of which constitutes an adoral organelle. After the separation of the tomites. the kinetosomes in the right buccal area position themselves, and the adoral organelles are completed by the addition of a 3rd row of kinetosomes. Somatic kineties are formed by successive pairs of ciliated kinetosomes united by 2 desmoses. the long posterior transverse ribbons and the postciliary ribbons extend posteriad, overlapping in the pellicular ridges. Oral rows of kinetosomes on the right can be compared with stichodyads. the adoral kinetosomes have convergent or divergent postciliary ribbons. the posterior row of kinetosomes in each organelle is not ciliated. By the type of stomatogenesis, the cortical ultrastructure, the ultrastructure adoral of its organelles, Bursaria belongs to the Colpodidea.     

Etude Ultrastructurale du Genre Enteromonas da Fonseca (Zoomastigophorea) et Révision de l'Ordre des Diplomonadida Wenyon

RESUME. Deux espèces d'Enteromonas sont observées, provenant, l'une de l'intestin de Triton, l'autre des crottes du Lapin domestique. La cellule piriforme porte un noyau antérieur et 4 flagelles insérts près du pôle ventral du noyau. Le flagelle récurrent (R) est logé dans une dépression ventrale ou cytostome. Les cinétosomes, disposés en une paire antérieure (#1, #2) et une paire postérieure (#3, R), sont liés entre eux par des microfibrilles. Une fibre microtubulaire située au-dessus du noyau est reliée au cinétosome #1. Une autre fibre microtubulaire sous-nucléaire est homologue de la fibre microtubulaire croisée qui existe chez les cellules de Diplozoaires. Le cytostome est bordé par 2 lèvres: la gauche proéminente et armée par plusieurs rangées de microtubules, la droite contenant seulement une mince fibre microtubulaire associée à des microfibrilles. Le cytostome occupe les 2/3 de la face ventrale. Le flagelle récurrent pénètre dans le cytostome puis dépasse l'extrémite de la cellule. Les Bactéries sont phagocytées au fond du cytostome, entre les 2 lèvres distendues. Elles sont digérées dans les nombreuses vacuoles et les corps résiduels sont évacués par rupture de la membrane cellulaire. L'ergastoplasme est concentré près de la périphérie de la cellule. Il n'y a pas de mitochondrie ni d'appareil de Golgi. Dans les kystes observés la cellule plurinucléée est enfermée dans une enveloppe kystique microfibrillaire, les axonèmes sont libres dans le cytoplasme. Les formes diplomonades sont nombreuses et ressemblent aux cellules d'Hexamita, excepté par le cytostome qui est différent. Dans ces formes, les 2 monades sont souvent disposées selon une symétrie axiale binaire mais quelquefois elles sont associées de façon plus anarchique. La cinétide d'Enteromonas est organisée comme celle d'un zoïde de Diplozoaire. Il est possible que le genre Enteromonas soit à l'origine des Diplomonadida et que l'état diplomonadien transitoire chez Enteromonas se soit stabilisé ensuite chez les Diplomonadida. Enteromonas apparaît plus primitif que les autres genres de Diplomonadida aussi nous proposons de créer 2 sous-ordres: celui des Enteromonadina avec le genre Enteromonas et celui des Diplomonadina avec les genres Trepomonas, Trigonomonas, Hexamita, Spironucleus, Octomitus, Giardia. La disposition des cinétosomes et l'existence du cytostome sont les principaux caractères communs entre Enteromonas et les Retortamonadida, cependant les fibres annexes ne sont pas homologues. Une étude plus complète de la division nucléaire et cellulaire de ces 2 ordres de Zooflagellés est nécessaire pour donner un meilleur schéma évolutif. SYNOPSIS. Fine structure of 2 species of Enteromonas, one from the intestine of the salamander, Triturus vulgaris, and another from the feces of domestic rabbit, Oryctolagus cuniculi, is described. The pyriform cell has an anteriorly located nucleus. The 4 flagella originate from an area near the anterior end of the nucleus. The recurrent flagellum (R) is lodged in a ventral depression or cytostome. The kinetosomes, arranged into 2 pairs, anterior (#1, #2) and posterior (#3, R), are interconnected by microfibrils. One microtubular fiber, connected to kinetosome #1, is situated near the anterior surface of the nucleus. Another, subnuclear, microtubular fiber is homologous to the “crossed'’fiber found in Diplozoa. The cytostome is bordered by 2 lips: the preeminent left lip is equipped with several rows of microtubules, while the right lip contains only a thin microtubular fiber associated with microfibrils. The cytostome occupies 2/3 of the ventral surface. The recurrent flagellum passes over the anterior surface of the cell and then comes to lie in the cytostome. The bacteria are phagocytosed in the bottom part of the cytostome between the 2 distended lips. They are digested in numerous vacuoles. The undigested residual bodies are evacuated by a rupture of the cell membrane. The ergastoplasm is concentrated near the cell periphery. Mitochondria and the Golgi apparatus are absent. In the cyst stage, the multinucleate cell is enclosed in a microfibrillar membrane; the axonemes lie free in the cytoplasm. Diplomonad forms of Enteromonas resembling Hexamita are numerous, except that the cytostome is different in these 2 genera. In such forms, the arrangement of the 2 individuals often has binary axial symmetry, but on occasion they are associated in a more anarchic fashion. The mastigont of Enteromonas is organized like that of a single zooid of a diplozoon. It is possible that the genus Enteromonas is ancestral to Diplomonadida and that the diplomonad state, transitory in Enteromonas, became permanently established in Diplomonadida. Enteromonas appears to be more primitive than the other genera of Diplomonadida. Thus we propose 2 suborders: Enteromonadina, subord. nov. with the genus Enteromonas, and Diplomonadina Wenyon, emend., with the genera Trepomonas, Trigonomonas, Hexamita, Spironucleus, Octomitus, Giardia. The arrangement of the kinetosomes and the existence of a cytostome are the principal characters common to Enteromonas and Retortamonadida, while their “accessory'’fibers are not homologous. A more complete study of division of the 2 zooflagellate orders is necessary for the presentation of a more detailed evolutionary scheme of these groups.     

Morphogenèse de Régénération chez le CiliéCondylostoma magnum (Spiegel): Etude ultrastructurale

SYNOPSIS Cortical events occurring in the course of regeneration in Condylostoma magnum (Spiegel) were studied by electron microscopy. The zone of regeneration is very rich in vacuoles and small vesicles formed from the plasma membrane. Multiplication of kinetosomes starts on the left side of kineties in the V-shaped left ventral area, normally implicated in stomatogenesis, at the level of the anterior kinetosomes of the somatic pairs. The proliferation proceeds by the appearance of young kinetosomes most often orthogonal to the old ones. This process of multiplication is very rapid and terminates in the formation of an “anarchic field” in which one observes that: (a) the newly formed kinetosomes do not possess all the associated postciliary fibers; and (b) when these fibers are detected, the kinetosomes are not in the same orientation. Differentiation of the adoral organelles takes place in the left part of the field (left primordium) by an alignment of the kinetosomes into 2 rows for each organelle (oriented perpendicularly to the antero-posterior axis of the ciliate), of which only one has the postciliary fibers. Ciliatogenesis occurs in numerous kinetosomes of the anarchic field; in certain kinetosomes it is achieved at the onset of their arrangement into organelles and is concomitant with growth of the nematodesmata. The 3rd (anterior) row of the organelles, the interkinetosomal desmata, and connections among neighboring organelles appear only secondarily. Differentiation of the paroral cilia occurs later. It takes place in the interior of the primordium, whose organization is primarily anarchic, and is accompanied by a progressive resorption of the major part of the newly formed kineties. Numerous kinetosomes of the right field have the associated postciliary fibers, which are not found at the level of the regenerated “polystichomonad” (paroral organization characteristic of C. magnum). Finally, the formation of new kinetosomes within a somatic kinety at the time of its elongation is described.     

Euplotes raikovi Agamaliev, 1966 (Ciliophora, Hypotrichida) From New Hampshire: Description and Morphogenesis

Euplotes raikovi, an interstitial hypotrich ciliate described once from the Caspian Sea, was isolated from intertidal sand at Rye Harbor, New Hampshire. Specimens were observed in life, and also stained by Corliss’ modification of the Chatton-Lwoff wet-silver technic and by 2 nigrosin methods. Living individuals and those fixed with Parducz's fluid are 43 × 30 (37-50 × 25–35) μm. The AZM has an average length of 27 μm and contains 24–32 membranelles. The anterior part of AZM lies on the ventral face of an apical channel, much as in E. bisulcatus. There are 7 fronto-ventral, 4 transverse, 1 left marginal, and 2 right caudal cirri. An additional small, rounded argentophilic area resembling a cirrus base is evident in silver-stained preparations, but it is barren in virtually 100% of the population. There are 7–8 (usually 7) dorsal ciliary rows with E. patella-type argyrome. The modal number of cilia in rows I-VII are 3-7-9-9-9-10-10. The unique fronto-ventral cirrus pattern is stable and predictable at the time of streak phase. Morphogenetic development indicates that the barren cirrus base is 2/V (Wallengren system), and that it apparently buds from 1/V. The left marginal cirrus and right caudal cirri have different origins.     

Description de Quelques Espèces de Ciliés Hyménostomes des Genres Sathrophilus Corliss, 1960, Cyclidium O. F. Müller, 1786, Histiobalantium Stokes, 1886

RESUME. Les structures buccales de Sathrophilus vernalis Dragesco & Grolière, 1969 sont détaillées. La morphogenèse buccale de l'opisthe, semi-autonome, avec participation du scuticus et d'une cinétie postorale droite, s'accompagne d'une re-constitution de l'appareil buccal du proter. La morphologie buccale de Cyclidium sphagnetorum Šràmek-Hušek, 1949 est comparée à celles de Cyclidium citrullus Cohn, 1865 et Cyclidium glaucoma O. F. Müller, 1786. La stomatogenèse Histiobalantium majus Kahl, 1933 débute par une prolifération du scuticus vers la gauche.
SYNOPSIS. Buccal structures of Sathrophilus vernalis Dragesco & Grolière, 1969 are described. The semiautonomous buccal morphogenesis of the opisthe, involving the participation of the scuticus and the right postoral kinety, is accompanied by the reconstitution of the buccal apparatus of the proter. The buccal structure of Cyclidium sphagnetorum Šràmek-Hušek, 1949 is compared to those of Cyclidium citrullus Cohn, 1865 and Cyclidium glaucoma O. F. Müller, 1786. Stomatogenesis of Histiobalantidium majus Kahl, 1933 starts with a proliferation of the scuticus towards the left.     

Biostratigraphie des Terebratulidae et des Zeilleriidaedu lias et du Dogger de la region toulonnaise (Var,France)

A lot of brachiopods have been sampled in stratigraphically well-defined beds of Liassic and Dogger periods in the region of Toulon (South of France). Now, numerous terebratulid and zeilleriid species are studied (in progress), the main biostratigraphic results of which are developed here in (fig. 1).     

Distribution et caractéristiques des associations d’ostracodes au Pléistocène supérieur et Holocène au niveau de la marge orientale du détroit de Gibraltar (mer d’Alboran, Maroc)

A detailed study of the upper Pleistocene and Holocene ostracode fauna from the Moroccan margin of the Western Mediterranean is here presented based on sediments of three cores drilled near the Straits of Gibraltar (Sea of Alboran), between 300 and 550 m of depth. Information on the quantitative and qualitative distribution of the ostracodes was obtained, for the first time, in this area. This study also allowed to identify recall the main climatic and eustatic variations as recorded in the sediments and the faunal composition and to identify the corresponding chronological limits from the last glacial maximum to the present time.     

Description of Pratylenchoides sheri n. sp. (Nematoda: Pratylenchidae)

Pratylenchoides sheri n. sp., a bisexual species from the Pacific coastal area of California, is described and illustrated. Its most distinctive characters are the esophageal glands slightly overlapping the intestine dorsally, the large ventrally slanting esophago-intestinal valve, the lack of labial sectors in the first lip annule, the presence of males, and apparently functional spermatheca. Pratylenchoides sheri is morphologically similar to P. magnicauda, but differs in length and labial conformation, its more anterior vulva, and the presence of males. Relationships of head and esophagus gland lobe characters of P. sheri are compared to other Pratylenchoides species.     

Ostracodes du Dévonien moyen et supérieur du Tafilalt (Maroc)

Forty-four ostracod species are recognised from the upper part of the Eifelian to the base of the Famennian of the Djebel Mech Irdane, Bou Tchrafine and El Atrous sections, in the Tafilalt. The majority are in open nomenclature, and one is new: Tubulibairdia tafilaltensis nov. sp. Ostracods belong principally to the Eifelian Mega-Assemblage and they are generally indicative of poorly oxygenated relatively deep marine environments below storm wave base. However, in the base of the Famennian of the Bou Tchrafine section, ostracods belong to the Myodocopid Mega-Assemblage indicative of strong hypoxic water conditions. They confirm that the hypoxic water conditions linked to the “Upper Kellwasser Horizon”, subsisted in North Africa, in the extreme base of the Famennian. Twenty-four ostracod species are recognized in the Djebel Mech Irdane Eifelian/Givetian stratotype, where the most important change in the ostracod fauna is related to the 40 cm-thick level of grey silty-marl located 10 cm below the boundary. However, this change is not indicative of an extinction event at this level. Three zones established on ostracods are recognized in the Frasnian and in the base of the Famennian of the Tafilalt.