The osteology of 38 skeletal elements is investigated in plaice, dextral and sinistral flounder, and dab with the aim of defining diagnostic characters that allow species identification of isolated bones from archaeological excavations. Five of these 38 skeletal elements have been mentioned in the literature as being diagnostic, but they appear to be unreliable for identification. All other elements allow identification, although only 23 permit the recognition of all three species. The individual bone elements and their diagnostic criteria are depicted and described in detail. Attention is paid to individual variation, and, when relevant, size-related morphological changes are also described. The keys that are developed for the various elements are finally tested on a large flatfish bone assemblage from an archaeological site. On the basis of these results, the success rate of the identifications for the various bones is discussed. Possible strategies for identification work on this group are suggested that take into account the extent of the reference collection, the time spent on the identifications and the experience needed in comparative osteology of these flatfish.
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Ants, the most abundant taxa among canopy-dwelling animals in tropical rainforests, are mostly represented by territorially-dominant arboreal ants (TDAs) whose territories are distributed in a mosaic pattern (arboreal ant mosaics). Large TDA colonies regulate insect herbivores, with implications for forestry and agronomy. What generates these mosaics in vegetal formations, which are dynamic, still needs to be better understood. So, from empirical research based on three Cameroonian tree species (Lophira alata, Ochnaceae; Anthocleista vogelii, Gentianaceae; and Barteria fistulosa, Passifloraceae), we used the Self-Organizing Map (SOM, neural network) to illustrate the succession of TDAs as their host trees grow and age. The SOM separated the trees by species and by size for L. alata, which can reach 60 m in height and live several centuries. An ontogenic succession of TDAs from sapling to mature trees is shown, and some ecological traits are highlighted for certain TDAs. Also, because the SOM permits the analysis of data with many zeroes with no effect of outliers on the overall scatterplot distributions, we obtained ecological information on rare species. Finally, the SOM permitted us to show that functional groups cannot be selected at the genus level as congeneric species can have very different ecological niches, something particularly true for Crematogaster spp. which include a species specifically associated with B. fistulosa, non-dominant species and TDAs. Therefore, the SOM permitted the complex relationships between TDAs and their growing host trees to be analyzed, while also providing new information on the ecological traits of the ant species involved. This article is protected by copyright. All rights reserved.
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We review progress made during the last 25 years in our understanding of the Protopityales, Early Carboniferous plants belonging to the extinct group of the progymnosperms. Recent studies support previous observations that the only genus of this order, Protopitys, included large arborescent plant with trunks up to 1 m in diameter. All branch orders had an oval eustele, secondary xylem with small rays and tracheid pitting ranging from circular bordered to scalariform bordered, and vascular traces to lateral appendages emitted in an alternate to subopposite distichous arrangement. Leaf morphology remains unknown. New material also confirms that fertile organs of Protopitys consist of branching systems bearing elongated sporangia terminally. Spores have a perispore and range in two size groups, which has been interpreted as a primitive stage of heterospory. The dense wood and fertile parts of Protopitys are comparable to those of the aneurophytalean progymnosperms of the Devonian, but Protopitys is distinct by its eustelic primary vascular system, and its affinities are still uncertain. The genus is now documented from at least nine localities in Europe, North America and Australia. Recent discoveries also indicate that it was present through the whole Mississippian, from the middle Tournaisian to the Serpukhovian.
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