Search results for "hydrozoa"
showing 10 items of 40 documents
Mediterranean species of Eudendrium Ehrenberg, 1834 (Hydrozoa, Anthomedusae, Eudendriidae) with the description of a new species
2000
A new species of Eudendrium from the Chafarinas Islands (south-western Mediterranean) is described. The distinctive character of this species is its association with symbiotic zooxanthellae, a feature in common with Myrionema, the only other genus of the family Eudendriidae. The evolutionary implications of this similarity are discussed. A review of the Mediterranean species of Eudendriidae is presented, including data on the cnidome when available, biological data from the material studied, and a key to identify the Mediterranean species.
Evidence for an instructive role of apoptosis during the metamorphosis of Hydractinia echinata (Hydrozoa)
2011
Apoptosis is a highly conserved mechanism of cell deletion that destroys redundant, dysfunctional, damaged, and diseased cells. Furthermore, apoptotic cell death is essential during the development of multicellular organisms. However, there are only a few examples where the occurrence of apoptosis has been shown to be a direct prerequisite for developmental processes. As described previously by our group, the degradation of larval tissue during the first half of the metamorphosis of Hydractinia echinata involves extensive cell death. A large number of cells are removed, and we observed several cellular features of apoptotic cell death in the dying tissue, e.g., nucleosomal DNA fragmentation…
Benthic hydroids from the south of Livingston Island (South Shetland Islands, Antarctica) collected by the Spanish Antarctic expedition Bentart 94
2006
Twenty-five species of benthic hydroids were collected during the Spanish Antarctic expedition Bentart 94 from the south of Livingston Island (Antarctica). All species are considered regarding autecology and geographical distribution. The systematic position amongst allied species is discussed when considered necessary. Antarctoscyphus asymmetricus and Symplectoscyphus nesioticus are reported for the second and the third time, respectively.
Antarctic hydroids (Cnidaria, Hydrozoa) of the families Campanulinidae, Lafoeidae and Campanulariidae from recent Antarctic expeditions with R.V.Pola…
2004
Species of the thecate hydroid families Campanulinidae, Campanulariidae and Lafoeidae have been studied. The material studied originates from the Weddell Sea and was collected by several French and German Antarctic expeditions with R.V. Polarstern. Fourteen species were found, three belonging to Campanulinidae, four to Campanulariidae and seven to Lafoeidae, one of these new to science (Filellum magnificum sp. nov.). The coppinia of Lafoea gaussica Vanhoffen, 1910, is described for the first time as well as the gonothecae of Opercularella belgicae (Hartlaub, 1904). A neotype is indicated for Filellum antarcticum (Hartlaub, 1904). Available data concerning autecology and geographical distrib…
Revision of the genusCryptolarellaStechow, 1913 (Lafoeidae, Leptothecata, Hydrozoa)
2005
The bathyal genus Cryptolarella, comprising three known species, Cryptolarella abyssicola (Allman, 1888), Cryptolarella diffusa (Allman, 1888) and Cryptolarella humilis (Allman, 1888), is reviewed after the study of the holotypes of the species. A complete redescription and characterization of the species, including new data concerning morphometry and cnidome is presented, and its literature data reviewed. We conclude that all species are conspecific, resulting in a single valid species, C. abyssicola. The distinctive characters of the species are the growth habit, gonothecal arrangement and cnidome.
Redescription of Bedotella armata from Biscay Bay, northern Spain, the type species of Bedotella Stechow, 1913 (Cnidaria, Hydrozoa, Lafoeidae), with …
2007
The circalittoral and bathyal genus Bedotella, comprising a unique known species endemic to the North European Atlantic (Lusitanian Province), Bedotella armata (Pictet, C. & M. Bedot, 1900) is redescribed based on a specimen from the Bay of Biscay, North Spain. As the holotype of the species, originally described as Campanularia armata, is sterile and incomplete, the present re-description includes new data concerning its morphometry, including gonothecae, and cnidom, as well as all the literature. The diagnostic characters of Bedotella armata are the presence of globular nematothecae, the campanuliform hydrothecae, and flabelliform, gigantic gonothecae. We corroborate the hypotheses of aff…
An overview of the phylogeny of the families Lafoeidae and Hebellidae (Hydrozoa:Leptothecata): their composition and classification
2006
A cladistic analysis of the genera of the family ‘Lafoeidae’ was performed in order to investigate suprageneric classifications and the boundaries of the family, as well as to organise the available morphological data and discuss the possible evolution of some morphological characters. Our results suggest that the former ‘Lafoeidae’ must be separated into two families: the Hebellidae and the Lafoeidae (including the subfamilies Lafoeinae and Zygophylacinae).
Phylogenetic analysis of the Antarctic genus Oswaldella Stechow, 1919 (Hydrozoa, Leptomedusae, Kirchenpaueriidae)
1999
A cladistic study was carried out on known species of the characteristically Antarctic genus Oswaldella, adopting as out-groups some other genera included in the family Kirchenpaueriidae. The analysis resulted in a cladogram with low CI in which no relationship between genera can be depicted. However, the hypothesis of monophyly of the genus Oswaldella is corroborated, being supported in our cladogram by five synapomorphies (although all are homoplastic with other taxa or reversed within the species of the genus). The basal relationships of the genus are uncertain, but three species groups are distinguishable within Oswaldella: 1) the O. incognita group, 2) the O. Antarctica group, and 3) a…
Benthic hydroids associated with volcanic structures from Bransfield Strait (Antarctica) collected by the Spanish Antarctic expedition GEBRAP96
2006
During the Spanish Antarctic expedition GEBRAP96 a survey to study the benthic fauna associated with deep volcanic structures in the Bransfield Strait was carried out. Amongst the benthic samples, a small collection of hydroids was gathered. A total of 10 species, most of them Leptothecata, was recorded; only two species of anthoathecates were present. Kirchenpaueriidae and Sertulariidae were the dominant families, and Symplectoscyphus and Oswaldella the predominant genera. Oswaldella niobae sp. nov. is described and figured. Since samples were taken at great depth, the lowest limit of the bathymetrical distribution for several species is distinctly increased. None of the samples showed sig…
Diversity, ecology and biogeography of Antarctic benthic hydrozoans: the Weddell Sea and the Scotia Arc as study cases
2017
Introducció: Les comunitats bentòniques que es desenvolupen a les aigües antàrtiques són altament singulars com a resultat d’un ambient relativament estable i aïllat. Tal aïllament és degut, entre altres factors, a la presència de la convergència Antàrtica, una forta barrera (o filtre) de temperatura i salinitat, que circumscriu de forma efectiva un dels ecosistemes marins més discrets i isolats geogràficament. Els factors abans esmentats han jugat un paper important en el desenvolupament d'un dels ecosistemes més rics del món pel que respecta a diversitat de fauna marina sèssil. Així doncs, la plataforma Antàrtica, més profunda que qualsevol altra plataforma continental, està constituïda p…