El género Ochrolechia A. Massai. (Pertusariaceae,liquenes) en Espana y Portugal

The genus Ochrolechia is widespread in Spain and Portugal and now includes 14 species, 1 form and 4 chemical races (11 species and 3 chemical races are epiphytes, 2 species, 1 form and 1 chemical race are saxicolous and one species is muscicolous). We propose a new combination: O. dalmatica (Erichsen) Boqueras. Eight species are excluded from the Spanish and Portuguese floras: O. aggregata (Bagl.) Verseghy, O. anomala Verseghy, O. glaucescens (Hue) Zahlbr., O.frigida (Sw.) Lynge, O. pseudotartarea (Vain.) Verseghy, O. rosella Müll. Arg., O. subpallescens Verseghy, O. tenuissima Verseghy, O. crozalsiana Clauzade et Vêzda is included in O. tartarea. The criteria for the identification of these species are: 1 ) the chemical substances (the presence/absence of gyrophoric acid in the thallus and/or in the apothecia determines the groups inside of the genus, the presence of alectoronic acid determines the chemical races); 2) thallus with or without soredia or isidia; 3) the presence of pruina on the disc; and 4) the substratum. A key for the identification to all mentioned species is included.     

Acanthocephalus tumescens (Acanthocephala, Echinorhynchidae) in Galaxias maculatus (Pisces, Galaxiidae) of Lake Gutiérrez, Patagonia, Argentina

The seasonal distribution of Acanthocephalus tumescens (Acanthocephala : Echinorhynchidae) among Galaxias maculatus (Pisces : Galaxiidae) in Lake Gutiérrez was studied from March 1994 to June 1996. Acanthocephalus tumescens always occurs in the intestine, has an overdispersed frequency distribution, a similar proportion of sexes, and females are larger than males. Mean intensity and prevalence are low and increase with host length. The pattern of the infection shows seasonality, with recruitment in winter and a reproductive period during spring-summer.     

Palaeontology of the Purbeck-type (Tithonian,Late Jurassic) bonebeds of Chassiron (Oléron Island,western France)

The paralic flora and fauna from the Late Jurassic of Chassiron (Oléron Island, western France) are described. The Tithonian-aged bonebeds of Purbeck facies of this locality have yielded a rich and diverse vertebrate assemblage including fishes, amphibians, reptiles and mammals, alongside numerous plant and invertebrate remains. The Chassiron locality thus appears as a peculiar Konzentrat-Lagerstätte in which most of the palaeoecosystem's biological components (both aquatic and terrestrial) have been preserved. The depositional environment was probably subject to salinity fluctuations, as indicated by the co-occurrence of freshwater and euryhaline organisms. This is one of the richest localities and the first mammal-bearing site known from the Jurassic of France.     

Solving the identity of the large Plagiomnium (Musci) from Madeira (Portugal): P. undulatum var. madeirense T. Kop. & C. Sérgio

A new variety of Plagiomnium undulatum (Hedw.) T. Kop. var. madeirense T. Kop. & C. Sérgio is described from Madeira Island. The plants present an aquatic ecology and are characterised by broadly and longly decurrent leaves and by large size of laminal cells. This taxon is illustrated and the specimens studied are mapped.     

Rhodymenia delicatula P.J.L. Dangeard (Rhodophyta,Rhodymeniales) en Méditerranée

Abstract

Presence of Rhodymenia delicatula P.J.L. Dangeard in the Mediterranean. - The presence of Rhodymenia delicatula P.J.L. Dangeard (Rhodophyta, Rhodymeniales) in the southern Thyrrhenian sea is reported. Both cystocarpic and tetrasporic individuals have been collected. Anatomical features of the reproductive structures, as well as the position of these on the thallus allowed the identification of this species formerly known for the Atlantic coasts of Morocco and British Isles.     

Création du genre Californiella N.gen. (Rhodophycophyta) et révision du genre DasyporellaStolley, 1893 (Dasycladales)

The genus Dasyporella was created by Stolley in 1893. Later, two different species were assigned to this genus under the same specific name Dasyporella norvegica. One of them was misinterpreted by Johnson & Konishi (1959) which introduced a confusion in the genus definition. The revision of the genus Dasyporella was therefore necessary and the study of new specimens belonging to the misinterpreted species have led to the creation of a new genus: Californiella. This new genus clarifies the concept of Dasyporella with the reinstatement of its original definition.     

Paleolimnology of the Petén Lake district,Guatemala

The long-term impact of Maya culture on a lowland tropical watershed is assessed, using data from a 9.2 m sediment core taken from deep water (28 m) in Lake Quexil. Human population growth, estimated by the 1980 archaeological survey, is associated with a shift in the composition of the sediment to a dominance by inorganic material, the Maya clay formation, beginning ca. 3500 B.P. Increasing settlement densities are correlated with accelerated influxes of phosphorus, carbonates, and siliceous sediment. However, chemical data do not track short-term population fluctuations closely. Because much of the sediment is delivered as colluvium, and not by running water, there is a lag between terrestrial disturbance and impact on the aquatic system. As an indication of this lag, contemporary high sedimentation rates are a residual of Maya activity that virtually ceased some 300–400 years B.P. Comparison of the deep-water core with a shallow-water (7 m) section, based on palynological correlation, reveals only minor differences in proximate chemical composition. Chemical influxes are much higher at the deep-water site, however, as a consequence of sediment focusing in this hyperconical basin. Chemical analyses of soil samples from 21 test pits in the Quexil basin support the principal conclusion that bulk soil movement was the mode of nutrient transfer to the lake, following forest clearance by the Maya.     

Ultrastructure des photorécepteurs de Lineus ruber (O. F. Müller) (Hétéronémertes Lineidae)

Résumé Lors de la régénération traumatique des yeux de Lineus ruber la différenciation biochimique des nouvelles cellules pigmentaires est séquentielle. On assiste à l'apparition successive des chaînes enzymatiques nécéssaires à la biosynthèse de porphyrine et de mélanine.Les études ultrastructurale et autoradiographique à haute résolution de ces phénomènes — montrent que la mélanisation s'opère au niveau d'organites cellulaires spécialisés (prémélanosomes, mélanosomes). La porphyrinogénèse se développe dans des vacuoles et organites d'origine golgienne qui participent également à la mélanogénèse.

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Ultrastructure of photoreceptors in Lineus ruber (O. F. Müller)

Summary In Lineus ruber the biochemical differentiation of the new pigmentary cells is sequential during the reparative regeneration of the eyes. The enzymatic pathways for porphyrin and melanin biosynthesis appear successively.Ultrastructural and high resolution radioautography studies, show that melanization occurs in specialized organelles called premelanosomes, melanosomes and melanin granules. Prophyrogenesis occurs in Golgi vesicles which are also involved in melanogenesis.

     

Biostatistical studies on western EuropeanDactylorhiza (Orchidaceae)—theD. maculata group

Multivariate analysis tools are exploited on a data set composed of quantitative characteristics collected on 35 populations of plants of theDactylorhiza maculata (L.)Soó group from Western-Europe. These samples lead to four well-defined clusters; this, together with qualitative, cytological and ecological arguments, allows for the recognition of four specific entities:D. maculata s.str.,D. fuchsii (Druce)Soó,D. saccifera (Brongn.)Soó andD. caramulensis (Vermeulen)Tyteca. It is concluded that the floral characters play an essential role in the taxonomical distinction. It also appears that the set of characters measured, as well as the methods exploited, are especially well-suited and valuable tools for the morphological study of the genusDactylorhiza.