Time filter

Source Type

Victoria, Canada

Lopes D.A.,Federal University of Rio de Janeiro | Hajdu E.,Federal University of Rio de Janeiro | Reiswig H.M.,Natural History Section | Reiswig H.M.,University of Victoria
Canadian Journal of Zoology | Year: 2011

The present study reports three species of Farrea Bowerbank, 1862 from Campos Basin (southwestern Atlantic): Farrea herdendorfi Duplessis and Reiswig, 2004, Farrea occa Bowerbank, 1862, and Farrea campossinus sp. nov. This is the first record of F. herdendorfi for the South Atlantic and only the second record of the species worldwide. Farrea occa is described and reported to form mass occurrences in the area's sponge and coral banks, as seen in extensive video recording undertaken between 900 and 1100 m depth. The new species approaches Farrea foliascens Topsent, 1906 very closely, but differs in that its hooked anchorate clavules are much larger and the meshes of its dictyonal framework rather more irregular. Our thoughts on whether the proposed new species deserved species or subspecies rank led to an investigation on the usage of subspecies rank in Porifera. A historical overview, mainly contrasting Demospongiae and Hexactinellida is offered here. We concluded that no rule of thumb is readily made out from the comparative analysis of various authors' taxonomic decisions. Until one such agreement is achieved, it appears to us that naming new subspecies should be objectively argued for, or better, totally avoided, as a useless further dimension to taxonomic uncertainty in poriferan classification. Source

Morgan N.B.,Florida State University | Cairns S.,Smithsonian Institution | Reiswig H.,Natural History Section | Reiswig H.,University of Victoria | Baco A.R.,Florida State University
Deep-Sea Research Part I: Oceanographic Research Papers | Year: 2015

In the North Pacific Ocean, the seamounts of the Hawaiian Archipelago and the Mid-Pacific Mountains are connected by Necker Ridge, a 600. km-long feature spanning a depth range of 1400-4000. m. The Necker Ridge is a part of a large area of the central and western Pacific under consideration for cobalt-rich manganese crust mining. We describe the fauna and community structure of the previously unsampled Necker Ridge based on explorations with the submersible Pisces IV. On five pinnacles and a portion of the Ridge ranging from 1400 to 2000. m deep, 27 transects were recorded using HD video, and voucher specimens were collected to aid in species identification. The video was analyzed to identify and count the megafauna found on each transect and to characterize the substrate. Diversity increased from south to north along the feature. There was a significant difference in community structure between southern and northern pinnacles, with southern pinnacles dominated by crinoids of the Family Charitometridae and northern pinnacles dominated by octocorals, especially the Families Isididae and Chrysogorgiidae. DistLM demonstrated a correlation between community structure on the pinnacles and at least six environmental variables, including latitude, sediment cover, and oxygen concentration, but not including depth. The discontinuous and patchy nature of these distinct megafaunal communities highlights growing evidence that cobalt-rich seamounts are highly heterogeneous habitats, and that managing seamounts may require more complex regulations than treating them as a single ecological unit. These results suggest that extensive community analysis should occur at a given site to determine management priority areas, prior to consideration of that site for exploitation of natural resources. © 2015 Elsevier Ltd. Source

Reiswig H.M.,Natural History Section | Reiswig H.M.,University of Victoria | Dohrmann M.,Ludwig Maximilians University of Munich
Zoological Journal of the Linnean Society | Year: 2014

Three new species and a new genus of dictyonal Hexactinellida (Hexasterophora: Sceptrulophora: Euretidae and Auloplacidae) are described from hard-bottom communities of the West Indies. The holotypes were all collected by manned submersibles operated by the Harbor Branch Oceanographic Institute between 2006 and 2011, and remained in excellent physical condition at the time of their examination and description. As a result of their relatively recent collection and ethanol storage, molecular markers established previously for the phylogenetics of glass sponges were retrievable from all three holotypes. These are the first sequences for their respective genera, Conorete, Verrucocoeloidea, and Dictyoplaxgen.nov. In addition, the first sequences of the genus Lefroyella could be obtained. Because the only (alleged) member of the family Euretidae previously included in molecular phylogenetic studies turned out to belong to the recently resurrected family Auloplacidae (i.e. Dictyoplaxgen.nov.), in the present study the phylogenetic position of Euretidae within Sceptrulophora could be inferred for the first time. Furthermore, the increased taxon sampling allowed us to conduct a first test of the monophyly of Euretidae and one of its two subfamilies, Euretinae, with molecular data. Maximum-likelihood phylogenetic analysis revealed a close relationship between Euretidae and Farreidae, but also indicated that Euretidae might be paraphyletic with respect to Farreidae. The monophyly of subfamily Euretinae, at least in its current scope, was strongly rejected by the molecular data, in line with results from other hexactinellid families with a subfamilial division. The genus Sarostegia, which was only recently provisionally moved to Euretidae, is here transferred to an incertae sedis position within the classification of Sceptrulophora, because it is clearly unrelated to the other three included euretids. Besides from that, we refrain from any changes to the classification of Euretidae until more genera of this most diverse but poorly defined sceptrulophoran family are sampled for molecular systematic studies. © 2014 The Linnean Society of London. Source

Reiswig H.M.,Natural History Section | Reiswig H.M.,University of Victoria
Journal of the Marine Biological Association of the United Kingdom | Year: 2014

Six new species of Hexactinellida are described from hard bottom communities of shelf, canyon and seamounts of the west coast of North America: Washington, British Columbia and Gulf of Alaska. They were collected by a variety of methods, trawl, manned submersible, and robot submersible, and hence vary greatly in condition. The six species comprise additions to five different families of the subclass Hexasterophora, Farreidae (Farrea omniclavata sp. nov. and F. truncata sp. nov.), Euretidae (Chonelasma oreia sp. nov.), Euplectellidae (Amphidiscella lecus sp. nov.), Leucopsacidae (Oopsacas olympicus sp. nov.) and Rossellidae (Acanthascus malacus sp. nov.). These additions represent an increase of 29% to the known species of Hexactinellida in this area. A completely unique form of defended tabulate stalk is described for A. lecus. The species Chauoplectella spinifera is transferred to Oopsacas. © Marine Biological Association of the United Kingdom, 2013. Source

Copley C.R.,Natural History Section | Winchester N.N.,University of Victoria
Canadian Journal of Forest Research | Year: 2010

In anthropogenically disturbed forested riparian ecosystems that contain vagile organisms, we expect dispersal to be a factor that determines patterns of diversity that differ from similar, but continuous, undisturbed habitats. We studied the effects of habitat alteration on community composition by characterizing the spider assemblage of a riparian corridor in an ancient forest and a regenerating coniferous forest in the Carmanah Valley, Vancouver Island, British Columbia. Spiders were collected over a 15 month period using Malaise traps set along transects perpendicular to Carmanah Creek. We recorded 76 genera and 113 species representing 23 families. In both the regenerating coniferous forest and the ancient forest, a large proportion of the species were of the family Linyphiidae. Species abundance was similar in the two habitats but diversity was greater in the regenerating coniferous forest. The ancient forest was dominated by the web-building guild. Spatial autocorrelation analysis revealed no overall pattern in the species assemblages relative to the riparian corridor. Bray-Curtis similarity measure and principal components analysis results indicate that spider assemblages in the two habitats were significantly different in composition. These results suggest that habitat changes affect assemblages of spiders by altering dispersal, and these responses are evident a decade after disturbance. Source

Discover hidden collaborations