117 research outputs found

    First record of a homolid crab (Crustacea: Decapoda: Homoloidea) from the early Eocene of the Iberian Peninsula

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    Se describe una nueva especie de cangrejo hom√≥lido, de la Formaci√≥n Roda, Ypresiano (Eoceno temprano) de la provincia de Huesca (Arag√≥n, Espa√Īa). A pesar de que el √ļnico ejemplar se halla parcialmente fragmentado, la similitud morfol√≥gica con especies actuales de los elementos conservados de la regi√≥n frontal y en especial el completo quel√≠pedo izquierdo, permite ubicarlo en el g√©nero Paromola Wood-Mason WoodMason and Alcock, 1891. Comparaciones con ejemplares actuales de Paromola cuvieri (Risso, 1815) confirmar√≠an la validez de esta ubicaci√≥n sistem√°tica. Paromola bretonin. sp. es el primer hom√≥lido reportado en el Cenozoico de la Pen√≠nsula Ib√©rica y amplia la riqueza de registros sobre dec√°podos f√≥siles del Eoceno en las cuencas Surpirenaicas. We describe a new species of homolid crab from the Ypresian (early Eocene) (Aragon, Spain). In spite of the fragmentary condition of the sole specimen, some preserved frontal elements, and in particular the complete left cheliped, allow inclusion it within in Wood-Mason and Alcock, 1891, based on morphological similarities with the extant species of this genus. Direct comparison with specimens of the extant Paromola cuvieri (Risso, 1815) confirms this systematic assignment. Paromola bretoni n. sp. is the first homolid reported in the Cenozoic of the Iberian Peninsula, and expands the rich decapod fossil record of the Eocene basins of southern Pyrenees

    Relationship of Homolidae and Dromiidae : evidence from spermatozoal ultrastructure (Crustacea, Decapoda)

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    The homolid spermatozoon, as exemplified by #Homola sp., #Paromola sp. and #Paromola petterdi, differs markedly from spermatozoa of crabs of the #Heterotremata - #Thoracotremata assemblage but agrees with the sperm of dromiids, in the strongly anteroposteriorly depressed acrosome (apomorphy?) and the capitate form of the perforatorium (a major synapomorphy seen nowhere else in the #Crustacea). These similarities support inclusion of the #Dromiidae and #Homolidae in a single grouping, the #Podotremata$. The homolid perforatorium differs from that of dromiids in the autapomorphic spiked-wheel form the anterior expansion. (D'après résumé d'auteur

    New deep-water cnidarian sites in the southern Adriatic Sea

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    Recent ROV (Remotely Operated Vehicle) exploration and bottom sampling in the southern Adriatic Sea (Apulian and Montenegrin margins) resulted in the discovery of cnidarian-rich deep-sea habitats in the depth range of ca. 400-700 m. In particular, ROV inspection of Montenegrin canyons reveals the existence of megabenthic communities dominated by a variety of cnidarians, including scleractinians (Madrepora oculata, Lophelia pertusa, Dendrophyllia cornigera),antipatharians (Leiopathes glaberrima) and gorgonians (Callogorgia verticillata) as major habitat forming taxa, often in association with sponges and, subordinately, serpulids. All such cnidarians are new records for the south-eastern side of the Adriatic Sea. Our investigation indicates that an almost continuous belt of patchy cold water coral sites occurs along the entire south-western margin (Apulian),basically connecting the Adriatic populations with those inhabiting the Ionian margin (Santa Maria di Leuca coral province)

    Illustrated keys for the identification of the Pleocyemata (Crustacea: Decapoda) zoeal stages, from the coastal region of south-western Europe

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    The identification keys of the zoeal stages of Pleocyemata decapod larvae from the coastal region of south-western Europe, based on both new and previously published descriptions and illustrations, are provided. The keys cover 127 taxa, most of them identified to genus and species level. These keys were mainly constructed upon external morphological characters, which are easy to observe under a stereomicroscope. Moreover, the presentation of detailed figures allows a non-specialist to make identifications more easily

    Dnevna slika migriranja kratkorepog raka, Maja crispata, Risso 1827 (Brachyura, Majidae)

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    Occurrence, distribution, and assemblage of crustaceans in the southern Adriatic Sea were determined from data collected during five seasonal (summer) trawl surveys carried out during 1996-2000. Trawls were conducted at a bathymetric range of 10-800 m, by the same vessel and same sampling gear in the framework of the E.U. Project, MEDITS. Fifty-two benthic-epibenthic, and nektonic species (three stomatopods, 49 decapods) were caught. Species density data (individuals per km2) were processed according to multivariate techniques to describe the composition and distribution of main pecies assemblages. The assemblages were consistent throughout the surveyed area with some differences between the western and eastern zones, mostly those found on shelf bottoms. The influence of oceanographic features, other than depth, is discussed.U sjevernom Jadranu su promatrana dnevna pomicanja populacije brahiurnog raka, Maja crispata. Odnos spolova, muŇĺjaka prema Ňĺenkama, iznosio je 3:2. MuŇĺjaci su imali maksimalnu duŇĺinu oklopa 91 mm, a Ňĺenke 74 mm. Maja crispata ńćeŇ°ńáe se nalazila na Ň°ljunkovitom dnu nego na bilo kojem drugom habitatu. Sedmero promatranih primjeraka nije se pomicalo prema nekom odreńĎenom podruńćju, nego se zadrŇĺavalo veńáim dijelom na tvrdom supstratu, izmeńĎu 0,8 i 3,5 m dubine. Maksimalna udaljenost od pońćetnog poloŇĺaja postignuta je u 9 dana, a iznosila je 16 metara

    Visual faunistic exploration of geomorphological human-impacted deep-sea areas of the north-western Mediterranean Sea

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    This study reports the composition and distribution of demersal megafauna from various north-western Mediterranean submarine areas such as canyons, seamounts and landslides between 60-800 m depth, based on remotely operated vehicle (ROV) observations. From a total of 30 h of video, 4534 faunistic observations were made and analysed in relationship to environmental factors (i.e. topography, substrate type and depth). In addition, anthropogenic impact was quantified by grouping observations in four categories: fishing nets, longlines, trawl marks and other litter. The different targeted environments showed similarities in faunal composition according to substrate, depth and topography. Our results also indicated the presence of anthropogenic impact in all the sampled areas in which litter and trawl marks were the most observed artefacts

    Zo√©s, megalopa e est√°gios juvenis iniciais de Cryptodromiopsis antillensis (Stimpson, 1858): implica√ß√Ķes sobre a monofilia dos Dromiacea (Crustacea: Decapoda: Brachyura)

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    The ontogeny of Cryptodromiopsis antillensis (Stimpson, 1858) it was analyzed through literature data (RICE & PROVENZANO, 1966) and observations of the megalopa, juveniles and adults. The megalopa of C. antillensis was redescribed and Evius ruber Moreira, 1912 was considered as synonym of C. antillensis by being of the phase megalopa of this species. The ontogeny of the carapace and the cephalic, thoracic and abdominal appendages it was accompanied separately. Carapace, antennule, antenna, mandible, maxillule, maxilla, first maxiliped, second maxiliped, third maxiliped and pereiopods suffer significant changes until the phase megalopa, when they acquire a similar form the one of the adult. After the phase megalopa these appendages just suffer increment of setae. Already the sternum thoracic, abdomen, telson, pleopods and uropods modify until the adult phase, presenting sexual dimorfism. Pl 1 is absent in the phases zoea and megalopa, just appearing in the juveniles ones. The presence of rudimentary pleopods was observed (Pl 3-Pl 5) in the male specimens of C. antillensis. Cryptodromiopsis. Antillensis, has the ontogenetic pattern of the family Dromiidae. The only species that outrange the Dromiidae pattern is Cryptodromia tuberculata, that presents abbreviated development. Ontogenetic data don't support the monophiletism of Podotremata. The zoea 1 of Dromiidae and the pre-zoea of Dynomenidae are similar. The ontogeny of Homolodromiidae came quite different from that of Dromiidae. The character rudimentary uropods (in a ventral view) in the megalopa phase, separates Homolodromiidae from all other Podotremata. Only one ontogenetic character justifies the Dromiacea sensu GUINOT (1978): antennal exopod developed in the megalopa. The ontogenetic pattern of the Archaeobrachyura sensu GUINOT (1978) was also studied. Ontogenetic data don't support the group of Archaeobrachyura. The following ontogenetic characters diagnoses Homoloidea: 4-6 setae and aesthetasc setae in the protopod of the antennule in the zoea 1; pattern of setae in the base (2, 2, ,2, 3) and in the endopod (1+0, 1+0, 1+0, 2+0, 4+1) of the Mxpl in the zoea 1; endopod of the Mxpl dividido in two articles in the megalopa; pattern of setae in the base (1, 1, 1, 1) of the Mxp2 in the zoea 1. Only one ontogenetic character is common to Raninidae and Cymonomidae: furcated telson.CAPESFUJBA ontogenia de Cryptodromiopsis antillensis (Stimpson, 1858) foi analisada atrav√©s de dados de literatura (RICE & PROVENZANO, 1966) e observa√ß√Ķes da megalopa, juvenis e adultos. A megalopa de C. antillensis foi redescrita e Evius ruber Moreira, 1912 foi considerada como sin√īnimo de C. antillensis por tratar-se da fase megalopa desta esp√©cie. A ontogenia da carapa√ßa e dos ap√™ndices cef√°licos, tor√°cicos e abdominais foi acompanhada separadamente. Carapa√ßa, ant√™nulas, antenas, mand√≠bulas, max√≠lulas, max√≠las, primeiro maxil√≠pede, segundo maxil√≠pede, terceiro maxil√≠pede e pere√≥podes sofrem mudan√ßas significativas at√© a fase megalopa, quando adquirem uma forma similar a do adulto. Ap√≥s a fase megalopa estes ap√™ndices sofrem apenas acr√©scimo de cerdas. J√° o esterno tor√°cico, abdomen, telso, ple√≥podes e ur√≥podes se modificam at√© a fase adulta, apresentando dimorfismo sexual. Pl 1 est√° ausente nas fases zo√© e megalopa, surgindo apenas nos juvenis. Foi observada a presen√ßa de ple√≥podes rudimentares (Pl 3-Pl 5) nos esp√©cimens macho de.. C. antillensis. A esp√©cie C. antillensis se encaixa no padr√£o ontogen√©tico da fam√≠lia Dromiidae. A √ļnica esp√©cie que foge ao padr√£o dromi√≠deo √© Cryptodromia tuberculata, que apresenta desenvolvimento abreviado. Dados ontogen√©ticos n√£o suportam a monofilia dos Podotremata. A zo√© 1 dos Dromiidae e a pr√©-zo√© dos Dynomenidae s√£o similares. A ontogenia do Homolodromiidae apresentou-se bastante diferente daquela dos Dromiidae. O car√°ter ur√≥podes rudimentares (vis√≠veis ventralmente) na fase megalopa, separa os Homolodromiidae de todos outros Podotremata. Apenas um car√°ter ontogen√©tico sustenta os Dromiacea sensu GUINOT (1978): exopodito da antena desenvolvido na megalopa. O padr√£o ontogen√©tico dos Archaeobrachyra sensu GUINOT (1978) tamb√©m foi estudado. Dados ontogen√©ticos n√£o fornecem suporte ao agrupamento dos Archaeobrachyura. Os seguintes caracteres ontogen√©ticos caracterizam os Homoloidea: 4-6 cerdas e estetos no protopodito da ant√™nula na zo√© 1; padr√£o de cerdas na base (2, 2, ,2, 3) e no endopodito (1+0, 1+0, 1+0, 2+0, 4+1) do Mxpl na zo√© 1; endopodito do Mxpl divdido em dois art√≠culos na megalopa; padr√£o de cerdas na base (1, 1, 1, 1) do Mxp2 na zo√© 1. Apenas um car√°ter ontogen√©tico √© comum ao Raninidae e Cymonomidae: telso furcado
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