La larve du genre Cyanothemis Ris, 1915 (Odonata: Anisoptera: Libellulidae). Conséquences phylogénétiques

La larve du genre Cyanothemis Ris, 1915 est décrite et illustrée pour la première fois. L’étude des adultes et des larves des genres Lepthemis Hagen, 1861, Rhodothemis Ris, 1911 et Cyanothemis Ris, 1915 suggère qu’ils sont étroitement apparentés, comblant ainsi une lacune phylogénétique vieille de presque un siècle. Le genre Acisoma Rambur, 1842, bien que plus dérivé, doit également être considéré appartenir au clade (Cyanothemis + Lepthemis + Rhodothemis). Les genres Nannophya Rambur, 1842 et Nannothemis Brauer, 1868 placés traditionnellement dans les Brachydiplacinae et non dans les Sympetrinae pourraient être les adelphotaxons du clade (Acisoma + Cyanothemis + Lepthemis + Rhodothemis). Lutilisation de la nervation alaire, jusqu’alors prépondérante, montre certaines limites dans la systématique et la phylogénie des Libellulidae.     

Découverte de faunes d'Ammonites de la zone à Platynota(Kimméridgien inférieur) dans les Monts de Chellala (avant-pays Tellien,Algérie); Conséquences stratigraphiques et paléogéographiques

In Chellala mountains (Seba el Abiod), in Western Algeria, new biostratigraphic data, based on Ammonites, allow characterize, for the first time in North Africa, the Platynota zone with the species-index Sutneria platynota. This species was known, to the present time, only in the South European border. These new biostratigraphic data show the diachronism of flyschoid facies. They do not exceed middle Oxfordian in the Tlemcenian zone; on the contrary they go up to lower Kimmeridgian in the preatlasic zone.     

Les pistes d’archosauriens : Kayentapus ubacensis nov. isp. (théropodes) et crocodylomorphes du Bathonien des Grands-Causses (France). Conséquences paléo-biologiques,environnementales et géographiques

Two tracksites yielding tridactyl footprints II-IV of theropods as well as supposedly sauropod tracks from the Causses Basin, briefly described in 2006 are reinvestigated. They are the Capelan tracksite (Meyrueis, Lozère) and the Garène tracksite (La Roque-Sainte-Marguerite, Aveyron), both Bathonian in age. In 2012, one of them (Le Capelan) was excavated and enlarged, allowing the discovery of numerous new tracks. In the Capelan tracksite, 102 concave epireliefs, 11 to 36 cm long, represent at least 21 trackways; the longest being visible along 37 meters. Footprints are almost as long as wide and show a large divarication angle II-IV (up to 70°). The largest of them (more than 24 cm long) were statistically compared with different Middle and Upper Jurassic ichnotaxa for which a synthesis is proposed. Tracks from the Causses Basin as well as those from the Capelan and the Garène tracksites can be ascribed to the ichnogenus Kayentapus. We propose a new ichnospecies K. ubacensis nov. isp. Whose trackmakers were tetanurian theropods, probably megalosaurids. At the Capelan, some marks are tentatively interpreted as swim tracks of crocodylomorphs. The supposedly sauropod tracks are here reinterpreted and considered as erosion cups and as concavities indicating the location of tree trunks. The sedimentological analysis indicates a paralic environment including lagoons and freshwater to brackish bays. They were separated from dysoxic lagoons by calcarenitic coastal barrier spits, and by tidal flats where microbial mats contributed to the good preservation of trackways. Despite the presence of “mangroves”, the main track-bearing surface from the Capelan was quite open and visited by megalosaurid dinosaurs of various sizes, moving in all directions but preferably to the North. The regional palaeogeography of the early-middle Bathonian is in accordance with a coastal area with low relief, bordering the “Seuil Cévenol”, which was probably emerged.     

Influence d'éclairements brefs, à différentes longeurs d'onde,sur les variations circadiennes des activités enzymatiques digestives chez Palaemon serratus (Crustacea,Natantia)

Abstract

The Influence of Short Periods of Lighting with Different Wavelengths on the Orcadian Changes of the Enzymatic Digestive Activities in Palaemon serratus (Crustacea, Natantia)

The effect of light on the circadian rhythms of digestive activities in the Shrimp Palaemon serratus have been studied.

1. Continuous darkness leads in a few days to a disappearance of the variations of the circadian rhythms of digestive enzymes while these rhythms go on in continuous light.

2. Short (1 or 2 hrs) and low intensity flashes of white light are effective in bringing on the reappearance of rhythmic variations in darkness.

3. We have been able to establish an isoquantic spectrum of action of the light. Two values of wavelength appears to account for a maximum sensibility of the shrimp: one in ultraviolet light and an other one, more important, in the green (λ=544 nm).

4. In green light it is possible to obtain the same effect of light by decreasing the time of stimulation to 5 or 10 mn and in increasing the total quantity of energy. Significant responses are obtained with total energy greater than 10000 pE. cm^‐2.

     

Évolution du taux de présence de spermatophore chez les femelles de Nephrops norvegicus (L.) (Decapoda:Reptantia) et développement ovarien

Ovary development and the presence of spermatophore in females of Nephrops norvegiens (L.) (Nephropidae) from South Brittany were studied from July 1976 to October 1978 through size classes. Percentage of females bearing spermatophores increased slowly up to 1978 during which year a sudden and important decrease was observed. The percentage decreased to the lowest value obtained in 1976. A study of ovarian development showed that the proportion of small females taking part in reproduction was greater in 1978 than in 1977.The beginning of the decrease in the percentage of spermatophores present coincided with the beginning of spawning in each size class. It may be explained by the behaviour of ovigerous females which stay in burrows during the incubation season. The decrease is, however, very important as the proportion of mature females is high and because the time separating the autumn moulting from spawning is great.Spawning occurred in several months (4 months in 1978). The “mean size at first maturity” varied from year to year and also from month to month, even if the presence of spermatophores was taken as a criterion.     

L’espèce en paléontologie : de l’utilisation du binôme linnéen chez les rongeurs fossiles (Mammalia,Rodentia)

Many species concepts have been proposed, but biologists and palaeontologists can use the same concept to interpret present and past biodiversity as well as evolution at the species level. But the present development of many disciplines creates the opportunity of reciprocal enlightenment of the pictures obtained of species according to different criteria: morphology, hybridization, and affiliation. Observations of long (geological) and short (biological, ecological) time intervals can consequently be more easily integrated. The increase in number of developmental studies is also an important event for understanding morphological evolution. In this context, the present work aims to comment on a few studies done on rodents (Rodentia, Mammalia), which successively deal with species recognition, estimation of past biodiversity, and the pictures given by fossils of morphological evolution.     

Étude autoradiographique de l'influence de la température sur la prolifération cellulaire chez les embryons âgés dePleurodeles waltlii Michah. (Amphibien,Urodéle)

Résumé Chez l'embryon de Pleurodèle au stade 34, la durée du cycle cellulaire et de ses phases varie peu selon les tissus mais dépend étroitement de la température. Le temps de génération et la durée de la phase S sont environ 3 ou 4 fois plus longs à 12° C qu'à 26° C. Lorsque la température s'élève, la phaseG₂ est abrégée dans les mêmes proportions que la phaseM; par contre, la durée de la phaseG₁ qui est nulle à 12° C s'allonge considérablement pour représenter environ 1/4 de la durée totale du cycle cellulaire à 26° C. La durée de cette phase est d'autant plus longue, à une température donnée, que les cellules sont plus différenciées. Les tissus étudiés représentent des populations cellulaires en croissance exponentielle. Le coefficient de prolifération, duquel dépend la base de la fonction exponentielle de croissance, est indépendant de la température mais particulier à chaque tissu. Il est d'autant plus faible que le tissu est plus différencié. En revanche, la vitesse de multiplication des cellules, qui est inversement proportionnelle au temps de génération, varie largement en fonction de la température; en outre, elle semble déterminer à elle seule la vitesse du développement des embryons aux températures choisies.

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Autoradiographic study of the effect of temperature on cellular proliferation in late embryos ofPleurodeles waltlii Michah. (Amphibia, Urodela)

Summary We observed in Pleurodeles embryos, stage 34, that the duration of the cell cycle and its phases was approximately the same for every tissue but was easily modified by varying the temperature. The generation time and the duration of S phase in embryos submitted to a 12° C temperature instead of 26° C are tripled or quadrupled. A temperature rise produced a proportionale shortening inG₂ andM phases and a lengthening inG₁ phase. ThisG₁ phase is not detectable at 12° C but represent a 1/4 of the total generation time at 26° C. The more differentiated the cells are, the longer is theG₁ time. The cell population studied during these experiments are growing exponentially. Growth fraction, which represents the exponential growth basis, is temperature independent but has a tissue specificity. This growth fraction is smaller the more the tissue is differentiated. However, the relative rate of cell division, inversely proportional to the generation time, is temperature dependent and appears to control the embryo's relative rate of growth under different temperatures.

     

Caractères ornementaux,disparité et diversité chez les Ammonitina : exemple des Kosmoceratinae (Stephanoceratoidea), Callovien moyen et supérieur (Jurassique moyen,Bassin parisien)

The Kosmoceratinae Tintant, 1963, consist of a subfamily of Jurassic Ammonitina of boreal origin, of which most species are highly polymorphic. Because of their rapid evolution and diversification they represent a major group for establishing Middle to Upper Callovian biostratigraphy. During its history, this taxon records an extreme and sudden diversification across the boundary between the substages. This step took place according to two distinct modes: 1- a rather progressive although rapid increase in both diversity and disparity of the dominant groups during most of the Middle Callovian; 2- a sudden two steps renewal of ornamental patterns giving rise to a quick reorientation of both disparity and diversity. This double event is well recorded and synchronous at the European scale.     

Azote et phosphore chez un crustacé macroplanctonique, Meganyctiphanes norvegica (M. Sars) (Euphausiacea): Excrétion minérale et constitution

Ammonia and phosphate excretion by the Mediterranean euphausiid Meganyctiphanes norvegica (M. Sars) (mean individual dry weight, 60 mg) has been measured for one year. Experiments were conducted at 13°C on single, freshly caught animals maintained in unfiltered sea water. Possible influence of these experimental procedures upon values obtained are discussed. Phytoplankton re-uptake and bacterial activity proved insignificant, because of the short duration of the experiments (4–38 h). NH₄ and PO₄ excretion rates are higher shortly after collection and then decrease, reaching a steady level after 8 h for NH₄, but continuously decreasing during the 38 h of the longer experiment in the c case of PO₄. It is considered that earlier higher values are likely to be more representative of in situ rates despite possible ‘stress’ effects, because they are close to those of moderately fed animals kept in captivity; more stable values observed after 8–12 h are close to those of starved animals. Nevertheless, lower stabilized values are best used when investigating seasonal variations. Excretion rates are low (0.07 to 0.11 μg-at.NH₄-N.mg^?1.day^?1, and 0.009 to 0.010 μ-at.PO₄-P mg^?1.day^?1) in summer, autumn and early winter. They rise sharply from January–February (0.12 μg-at.NH₄-N.mg^?1.day^?1 and 0.015 μg-at.PO₄-P.mg^?.day^?1) to peak spring values (0.25 μg-at.NH₄-N.mg^?1.day^?1 and 0.026 μg-at. PO₄-P.mg^?1.day^?1). The significance of inorganic excretion with regard to total (inorganic + organic) excretion is discussed. The nitrogen and phosphorus content of the animals were simultaneously measured and amount, respectively, to 9.5 and 0.8% of body dry weight (mean yearly value). Based on inorganic excretion only, the mean values of turnover are 66 days for nitrogen (61–92 days from May to February, 28–32 days in March–April) and 16 days for phosphorus (12–22 days with limited seasonal variation). Mean N/P ratio by atoms for excretion amounts to 9.1 after 8–12 h (it increases afterwards due to continual decrease in PO₄ excretion) but there are significant seasonal variations. The mean N/P ratio by atoms for the animals is 27.4; it is lower (22.4) between March and August, and higher (29.2) from September to February. With a view to investigating the change in the N/P ratio in the chain prey → predator → excretion, which allows calculation of growth efficiency factor (k₂) and hence secondary production, the nitrogen and phosphorus of the stomach contents of the animals were measured. Due to unknown bias (possibly a terrestrial origin of food particles, or loss of phosphorus during conservation of samples), the results were disappointing (N/P by atoms = 69, instead of a value necessarily ranging between 9.1 and 27.4), and did not allow calculation of k₂.     

Une nouvelle espèce de Pseudamaurops Jeannel, 1948 du Monténégro,et remarques sur les genres voisins (Coleoptera: Pselaphinae: Amauropini)

Une nouvelle espèce du genre Pseudamaurops Jeannel, 1948, récoltée dans une grotte à proximité de Virpazar, au Monténégro, et décrite et illustrée. Il s’agit là du troisième représentant du genre, deux autres espèces ayant été décrites d’Albanie. La position taxonomique de la nouvelle espèce est discutée, quelques remarques sur le genre et deux genres apparentés, Bergrothia Reitter, 1884 et Zoufalia Reitter, 1918, sont fournies.     

Découverte d’un micro-organisme commensal impliqué dans une crise biologique chez les gilianelles du Crétacé de Tercis (Landes,France) : Convictorella pusula,nov. gen. nov. sp. (microproblematica)

Discovery of a commensal microfossil involved in a biological crisis among the Cretaceous gilianelles of Tercis (Landes, France): Convictorella pusula nov. gen., nov. sp., (microproblematica). The recently discovered gilianelles commonly show attached microspheres. The morphological relationships indicate that this association is of biological origin with benefit for the microspheres but not for the gilianelles. A local bloom of the commensal microspheres (age estimate: about 73 Ma) coincides with a biological crisis in the evolutionary pattern of the gilianelles. The group convictorelles (microproblematica) and the species Convictorella pusula n. gen. n. sp. are created for this original ethological relationship.