As the most ancient extant metazoans, glass sponges (Hexactinellida) have attracted recent attent... more As the most ancient extant metazoans, glass sponges (Hexactinellida) have attracted recent attention in the areas of molecular evolution and the evolution of conduction systems but they are also interesting because of their unique histology: the greater part of their soft tissue consists of a single, multinucleate syncytium that ramifies throughout the sponge. This trabecular syncytium serves both for transport and as a pathway for propagation of action potentials that trigger flagellar arrests in the flagellated chambers. The present chapter is the first comprehensive modern account of this group and covers work going back to the earliest work dealing with taxonomy, gross morphology and histology as well as dealing with more recent studies. The structure of cellular and syncytial tissues and the formation of specialised intercellular junctions are described. Experimental work on reaggregation of dissociated tissues is also covered, a process during which histocompatibility, fusion ...
Philosophical Transactions of the Royal Society B: Biological Sciences, 1983
Downloaded from rstb.royalsocietypublishing.org on June 4, 2011 Phil. Trans. R. S00. L0mi. B 301,... more Downloaded from rstb.royalsocietypublishing.org on June 4, 2011 Phil. Trans. R. S00. L0mi. B 301, 419-42s (1983) [ 419 ] Printed in Great Britain 1 2 3 4. 5 6. STUDIES ON HEXACTINELLID SPONGES. III. THE TAXONOMIG STATUS OF HEXACTINELLIDA WITHIN THE ...
Glass sponges are enigmatic members of the deep-sea fauna that inhabit shallow waters in only a f... more Glass sponges are enigmatic members of the deep-sea fauna that inhabit shallow waters in only a few locations world-wide. In order to understand what factors influence the distribution of glass sponges, patterns of distribution and abundance of reef and non-reef forming hexactinellids in fjords of British Columbia, Canada, were analyzed from photographs and transcripts recorded on dives undertaken by the 'Pisces IV' manned submersible during the 1980s. Hexactinellids are widely distributed throughout all fjords from 16 to 650 m depths, and in some fjords abundances reach 240 individuals in 10 m 2 . In all fjords hexactinellids were most abundant at depths of 20 to 260 m, even where water depths exceeded 500 m. Glass sponges were rare in regions of inlets where oxygen levels fall below 2 ml l -1 , or in areas of high sediment deposition. Highest abundances coincided with water conditions of high dissolved silicate, low light, temperatures between 9 and 10°C and low suspended sediments. Extensive glass sponge skeletons in the inner basin of Howe Sound reflect past stress in this fjord that may include oxygen deficit, sediment loading from a mine and contamination from industrial sites. The observations from 'Pisces IV' suggest that glass sponges may be sentinel species for current and past seawater conditions in coastal British Columbia.
Samples of the population of Yoldia limatula Say were obtained from the Bideford River, Malpeque ... more Samples of the population of Yoldia limatula Say were obtained from the Bideford River, Malpeque Bay, Prince Edward Island, Canada, during the summers of 1979 and 1980 by means of a dredge and a Ponar grab sampler. Size frequency analysis demonstrated that individuals in the size range 25-to 35-ram shell length were numerically dominant in May, June and July. Recruitment of juveniles in August resulted in the dominance of individuals of 5 mm and smaller which comprised 50% of the population at that time. The overall sex ratio was 48.8% males to 51.2% females. From annual lengths measured at successive winter growth bands it was determined that one-yr olds attained a shell length of between 13.8 and 17.7 ram, two-yr olds between 26.7 and 28.0 ram, three-yr olds between 33.8 and 35.2 mm, and four-yr olds had a mean length of 38.7mm. Y. limatula produced a croppable annual yield of between 1.19 and 2.65 g dry tissue weight m -2 with P/B ratios of 0.65 and 1.45 respectively.
Six species of common Caribbean Zoanthidea, Parazoanthus swiftii, P. parasiticus, P. catenularis,... more Six species of common Caribbean Zoanthidea, Parazoanthus swiftii, P. parasiticus, P. catenularis, P. puertoricense, Epizoanthus cutressi, and Epizoanthus sp., are virtually restricted to living on surfaces of reef dwelling sponges. Quantitative surveys on Barbados reefs indicate that substrate specificity is relatively high among these zoanthids with three restricted to a single primary host sponge species and three restricted to three closely related sponges. One species, P. swiftii, exhibits a broad range of acceptable secondary substrates, due to its unique ability to execute migrational spread in the adult polyp stage. Variations in substrate specificity have been noted between island populations within the extensive Caribbean range and appear to be due to different species compositions of local sponge communities and slight differences in zoanthid larval settling specificities.
l. Gemmules of Ephydatia miilleri can withstand exposure to temperatures down to -80°C for 63 day... more l. Gemmules of Ephydatia miilleri can withstand exposure to temperatures down to -80°C for 63 days without loss of hatchability.
Two new species of the hexactinellid family Tretodictyidae, both collected by submersible, have b... more Two new species of the hexactinellid family Tretodictyidae, both collected by submersible, have been discovered off the coasts of North America. The Pacific species, Tretodictyum montereyensis n. sp., has an unusual skeleton with a fused cortex added over the usual tretodictyid system of ridges and grooves on the dermal surface. The Atlantic species, Hexactinella carolinensis n. sp., is unusual among its congeners in having swollen nodes on the dermal skeleton. Diagnoses of both genera have been modified to accommodate the new findings. The fine diactins of both species are found to have shallow brackets and short barbs, confirming their uncinate nature. Addition of these two species raises the number of known North American tretodictyids from one to three.
1988. Ecology, functional morphology, behaviour, and feeding in coral-and sponge-boring species o... more 1988. Ecology, functional morphology, behaviour, and feeding in coral-and sponge-boring species of Upogebia (Crustacea: Decapoda: Thalassinidea). Can. J. Zool. 66: 483 -495. Species of Upogebia, commonly found as infaunal bioturbators of soft sediments in marine coastal environments, have been discovered inhabiting burrows in coral and siliceous demosponges on tropical reefs. Upogebia operculata is experimentally demonstrated to actively bore into the calcium carbonate skeleton of the coral Porites astreoides. An undescribed species of Upogebia burrows into the sponge Agelas sceptrum. Morphological and behavioural adaptations to these habitats are more striking in the coral-boring species, including the development of probable boring glands and an unusually shaped tail fan.
As the most ancient extant metazoans, glass sponges (Hexactinellida) have attracted recent attent... more As the most ancient extant metazoans, glass sponges (Hexactinellida) have attracted recent attention in the areas of molecular evolution and the evolution of conduction systems but they are also interesting because of their unique histology: the greater part of their soft tissue consists of a single, multinucleate syncytium that ramifies throughout the sponge. This trabecular syncytium serves both for transport and as a pathway for propagation of action potentials that trigger flagellar arrests in the flagellated chambers. The present chapter is the first comprehensive modern account of this group and covers work going back to the earliest work dealing with taxonomy, gross morphology and histology as well as dealing with more recent studies. The structure of cellular and syncytial tissues and the formation of specialised intercellular junctions are described. Experimental work on reaggregation of dissociated tissues is also covered, a process during which histocompatibility, fusion ...
Philosophical Transactions of the Royal Society B: Biological Sciences, 1983
Downloaded from rstb.royalsocietypublishing.org on June 4, 2011 Phil. Trans. R. S00. L0mi. B 301,... more Downloaded from rstb.royalsocietypublishing.org on June 4, 2011 Phil. Trans. R. S00. L0mi. B 301, 419-42s (1983) [ 419 ] Printed in Great Britain 1 2 3 4. 5 6. STUDIES ON HEXACTINELLID SPONGES. III. THE TAXONOMIG STATUS OF HEXACTINELLIDA WITHIN THE ...
Glass sponges are enigmatic members of the deep-sea fauna that inhabit shallow waters in only a f... more Glass sponges are enigmatic members of the deep-sea fauna that inhabit shallow waters in only a few locations world-wide. In order to understand what factors influence the distribution of glass sponges, patterns of distribution and abundance of reef and non-reef forming hexactinellids in fjords of British Columbia, Canada, were analyzed from photographs and transcripts recorded on dives undertaken by the 'Pisces IV' manned submersible during the 1980s. Hexactinellids are widely distributed throughout all fjords from 16 to 650 m depths, and in some fjords abundances reach 240 individuals in 10 m 2 . In all fjords hexactinellids were most abundant at depths of 20 to 260 m, even where water depths exceeded 500 m. Glass sponges were rare in regions of inlets where oxygen levels fall below 2 ml l -1 , or in areas of high sediment deposition. Highest abundances coincided with water conditions of high dissolved silicate, low light, temperatures between 9 and 10°C and low suspended sediments. Extensive glass sponge skeletons in the inner basin of Howe Sound reflect past stress in this fjord that may include oxygen deficit, sediment loading from a mine and contamination from industrial sites. The observations from 'Pisces IV' suggest that glass sponges may be sentinel species for current and past seawater conditions in coastal British Columbia.
Samples of the population of Yoldia limatula Say were obtained from the Bideford River, Malpeque ... more Samples of the population of Yoldia limatula Say were obtained from the Bideford River, Malpeque Bay, Prince Edward Island, Canada, during the summers of 1979 and 1980 by means of a dredge and a Ponar grab sampler. Size frequency analysis demonstrated that individuals in the size range 25-to 35-ram shell length were numerically dominant in May, June and July. Recruitment of juveniles in August resulted in the dominance of individuals of 5 mm and smaller which comprised 50% of the population at that time. The overall sex ratio was 48.8% males to 51.2% females. From annual lengths measured at successive winter growth bands it was determined that one-yr olds attained a shell length of between 13.8 and 17.7 ram, two-yr olds between 26.7 and 28.0 ram, three-yr olds between 33.8 and 35.2 mm, and four-yr olds had a mean length of 38.7mm. Y. limatula produced a croppable annual yield of between 1.19 and 2.65 g dry tissue weight m -2 with P/B ratios of 0.65 and 1.45 respectively.
Six species of common Caribbean Zoanthidea, Parazoanthus swiftii, P. parasiticus, P. catenularis,... more Six species of common Caribbean Zoanthidea, Parazoanthus swiftii, P. parasiticus, P. catenularis, P. puertoricense, Epizoanthus cutressi, and Epizoanthus sp., are virtually restricted to living on surfaces of reef dwelling sponges. Quantitative surveys on Barbados reefs indicate that substrate specificity is relatively high among these zoanthids with three restricted to a single primary host sponge species and three restricted to three closely related sponges. One species, P. swiftii, exhibits a broad range of acceptable secondary substrates, due to its unique ability to execute migrational spread in the adult polyp stage. Variations in substrate specificity have been noted between island populations within the extensive Caribbean range and appear to be due to different species compositions of local sponge communities and slight differences in zoanthid larval settling specificities.
l. Gemmules of Ephydatia miilleri can withstand exposure to temperatures down to -80°C for 63 day... more l. Gemmules of Ephydatia miilleri can withstand exposure to temperatures down to -80°C for 63 days without loss of hatchability.
Two new species of the hexactinellid family Tretodictyidae, both collected by submersible, have b... more Two new species of the hexactinellid family Tretodictyidae, both collected by submersible, have been discovered off the coasts of North America. The Pacific species, Tretodictyum montereyensis n. sp., has an unusual skeleton with a fused cortex added over the usual tretodictyid system of ridges and grooves on the dermal surface. The Atlantic species, Hexactinella carolinensis n. sp., is unusual among its congeners in having swollen nodes on the dermal skeleton. Diagnoses of both genera have been modified to accommodate the new findings. The fine diactins of both species are found to have shallow brackets and short barbs, confirming their uncinate nature. Addition of these two species raises the number of known North American tretodictyids from one to three.
1988. Ecology, functional morphology, behaviour, and feeding in coral-and sponge-boring species o... more 1988. Ecology, functional morphology, behaviour, and feeding in coral-and sponge-boring species of Upogebia (Crustacea: Decapoda: Thalassinidea). Can. J. Zool. 66: 483 -495. Species of Upogebia, commonly found as infaunal bioturbators of soft sediments in marine coastal environments, have been discovered inhabiting burrows in coral and siliceous demosponges on tropical reefs. Upogebia operculata is experimentally demonstrated to actively bore into the calcium carbonate skeleton of the coral Porites astreoides. An undescribed species of Upogebia burrows into the sponge Agelas sceptrum. Morphological and behavioural adaptations to these habitats are more striking in the coral-boring species, including the development of probable boring glands and an unusually shaped tail fan.
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