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Hans Heinrich Janssen - One of the best experts on this subject based on the ideXlab platform.
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The body wall of Halicryptus spinulosus (Priapulida) — ultrastructure and changes induced by hydrogen sulfide
Hydrobiologia, 1992Co-Authors: Hans Heinrich Janssen, Rolf OeschgerAbstract:Halicryptus spinulosus (Priapulida) is extraordinarily resistant to hydrogen sulfide. As described previously, the body wall of specimens from oxic and from hydrogen sulfide-contaminated habitats differs strikingly in colour. In the present paper the ultrastructure of the body wall of specimens kept under oxic conditions is described. These findings serve as a reference for changes induced by exposure to hydrogen sulfide. There are marked ultrastructural differences between epidermal and muscular mitochondria exposed to hydrogen sulfide. Epidermal mitochondria of individuals subjected to hydrogen sulfide are often associated with dense granules of unknown composition. Findings are compared with those from other taxa which may encounter hydrogen sulfide in their environment.
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the body wall of halicryptus spinulosus Priapulida ultrastructure and changes induced by hydrogen sulfide
Hydrobiologia, 1992Co-Authors: Hans Heinrich Janssen, Rolf OeschgerAbstract:Halicryptus spinulosus (Priapulida) is extraordinarily resistant to hydrogen sulfide. As described previously, the body wall of specimens from oxic and from hydrogen sulfide-contaminated habitats differs strikingly in colour. In the present paper the ultrastructure of the body wall of specimens kept under oxic conditions is described. These findings serve as a reference for changes induced by exposure to hydrogen sulfide. There are marked ultrastructural differences between epidermal and muscular mitochondria exposed to hydrogen sulfide. Epidermal mitochondria of individuals subjected to hydrogen sulfide are often associated with dense granules of unknown composition. Findings are compared with those from other taxa which may encounter hydrogen sulfide in their environment.
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Histological studies on Halicryptus spinulosus (Priapulida) with regard to environmental hydrogen sulfide resistance
Hydrobiologia, 1991Co-Authors: Rolf Oeschger, Hans Heinrich JanssenAbstract:The priapulid Halicryptus spinulosus has an outstanding resistance to anoxia and hydrogen sulfide, which enables the animal to survive in deteriorating environments. Whole-body staining procedures, as well as light and scanning electron microscopy were used to study structures and mechanisms possibly involved in sulfide detoxification. The cuticle of the trunk is covered by a coat of mucus and bacteria. Within this coat considerable amounts of finely dispersed iron are precipitated, probably as a Fe^2+-compound. It is suggested that the iron functions as a rechargeable buffer against hydrogen sulfide, protecting both the bacteria and the priapulid host. Although this chemical shield may not alone account for long-term protection, it allows the animal to gain time for metabolic adaptations.
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Histological studies on Halicryptus spinulosus (Priapulida) with regard to environmental hydrogen sulfide resistance
Hydrobiologia, 1991Co-Authors: Rolf Oeschger, Hans Heinrich JanssenAbstract:The priapulid Halicryptus spinulosus has an outstanding resistance to anoxia and hydrogen sulfide, which enables the animal to survive in deteriorating environments. Whole-body staining procedures, as well as light and scanning electron microscopy were used to study structures and mechanisms possibly involved in sulfide detoxification.
Volker Storch - One of the best experts on this subject based on the ideXlab platform.
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Histochemistry of lectin-binding sites in Halicryptus spinulosus (Priapulida).
Acta histochemica, 2001Co-Authors: Anette Busch, Udo Schumacher, Volker StorchAbstract:Summary Priapulida represent one of the phylogenetically oldest multicellular animal groups. In multicellular animals (Metazoa) cell-to-cell and cell-to-matrix interactions are often mediated by carbohydrate residues of glycoconjugates. To analyze the carbohydrate composition of a phylogenetically old species, lectin histochemistry was employed on 5 specimens of the priapulid Halicryptus spinulosus . Many lectins bound to the chitin-containing cuticle, including those specific for carbohydrates other than N-acetylglucosamine, the principle building block of chitin. The connective tissue of the animals contained both N-acetylglucosamine and N-acetylgalactosamine. Mannose residues were widely distributed with the exception of the cuticle, but complex type carbohydrates were not present in the entire animal. Sialic acid residues were only detected in the cuticle and brush border of the intestinal epithelium, while fucose was limited to the cuticle. Thus, the lectin-binding pattern indicated that sugars typical for the linking region of both N- and O-glycoproteins in mammals are also present in H. spinulosus . Carbohydrate residues that are typical for the complex type of N-linked glycans in vertebrates are not present as are carbohydrate residues typical for the termination of O-linked carbohydrate chains. Hence, a truncated form of both N- and O-linked glycosylation is present in H. spinulosus indicating that more complex patterns of glycosylation developed later during evolution.
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Halicryptus higginsi n.sp. (Priapulida): A Giant New Species from Barrow, Alaska
Invertebrate Biology, 1999Co-Authors: Thomas C. Shirley, Volker StorchAbstract:A new species of Priapulida was discovered from the Beaufort Sea near Barrow, Alaska. Following an unusually strong autumnal storm, 30 adult specimens of Halicryptus higginsi n.sp. were collected, many alive, from intertidal beaches Additional specimens were found in museum collections misidentified as Halicryptus spinulosus von Siebold 1849. The new species represents the 11th priapulid species described since 1968 and increases the number of described extant species of Priapulida to 18. While all other recently described priapulids have been meiofaunal, Halicryptus higginsi n.sp. is macrofaunal and the largest extant priapulid species, with one specimen being 39 cm long in a contracted condition. Additional key words: arctic, benthos In recent years the concept of the marine phylum Priapulida has changed radically, from that of a macrobenthic, cold-water taxon, to one that is more speciose in the tropical meiofauna. Before 1968, only 7 extant species were known and additional species had been described from the fossil record; all extant species were macrobenthic and found only in cold-water habitats (Higgins et al. 1993). In 1968 the first meiobenthic priapulid, Tubiluchus corallicola VAN DER LAND 1968, was described from a tropical, shallowwater habitat (van der Land 1968). Since 1968 an additional 9 priapulid species, all meiobenthic and mostly inhabitants of tropical, shallow-water sediments, have been described. Tubiluchus arcticus ADRIANOV, MALAKOV, CHESUNOV, & TSETLIN 1989 is the only cold-water species that has been described in recent years, and it is a meiofaunal priapulid that inhabits shallow-water sediments in the arctic (Adrianov et al. 1989). During a survey of museum specimens of priapulids, one of us (VS) discovered that specimens in the United States National Museum of Natural History, Smithsonian Institution, misidentified as Halicryptus spinulosus von Siebold from Barrow, Alaska, had been used for scanning electron microscopy (Merriman 1981) and instead represented a new and undescribed congener. Subsequent to the museum discovery we found larvae and juveniles of the undescribed species a Author for correspondence. E-mail: fftcs@uaf.edu in the shallow subtidal during two expeditions to Barrow, Alaska in 1991 and 1992, but did not find adults of the new species. Following an unusually strong autumnal storm in 1993, 30 adult specimens of Halicryptus higginsi n.sp. were collected, many alive, from intertidal beaches near Barrow. In this paper we describe the new species and compare it with H. spinulosus. The larvae will be described in a separate pub-
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Coccidian intestinal parasites in the Priapulidae (Priapulida)
Parasitology research, 1997Co-Authors: Juan F. Saldarriaga, Volker StorchAbstract:Four relatively uncommon members of the family Priapulidae (Priapulida) from very different parts of the world were examined to determine the presence of a parasitic coccidian in their midgut. The parasite was found in three of those priapulid species, Priapulopsis bicaudatus, P. australis, and Halicryptus higginsi, but not in the fourth one, Priapulus tuberculatospinosus. Using electron-microscopy techniques, we compared parasites of the different species with one another and with a parasite of Priapulus caudatus investigated by McLean in 1984. All of these parasites apparently belong to the same species and are likely to be Alveocystis intestinalis, a coccidian first described by Beltenev from P. caudatus and H. spinulosus. The present work greatly expands the geographical range of Alveocystis intestinalis and documents an uncommon case of low host specificity in eimeriid coccidians.
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icy heritage ecological evolution of the postglacial baltic sea reflected in the allozymes of a living fossil the priapulid halicryptus spinulosus
Marine Biology, 1996Co-Authors: Arnd Schreiber, H. Rumohr, M Eisinger, Volker StorchAbstract:Genetic variation of 16 allozyme loci in 397 Halicryptus spinulosus (Priapulida) revealed overall polymorphism of P=0.438 and Hardy-Weinberg expectations for heterozygosity of He=0.060 for Baltic Sea stocks, He=0.143 for the White Sea and He=0.121 for Iceland. Maximal unbiased standard distances of D=0.0693 separated Baltic and White Sea populations. Nordic and Baltic populations could be distinguished by allozymes, but Baltic subsamples proved cohesive. Gene flow amounted to effective exchange values per generation of Nm=2.94 over 650 km of continuous habitat, Nm=10.65 over 175 km, and Nm=13.85 over 20 km. Gene flow started to decrease with geographic distance beyond a dispersal threshold of 20 km, but hierarchical GST-statistics indicated light isolation by distance beyond a minimum of 8 km. Gene flow is high for a benthic worm assumed to lack dispersal by pelagic larva, a paradox which cannot be resolved now. Baltic populations are characterized by lower heterozygosity than Nordic stocks. In the Baltic Basin, temporally continuous brackish-water conditions have only existed for the past 7000 years. The two possible colonization routes of H. spinulosus to the geologically young Baltic Sea imply genetic drift, whether by founder effect (sweepstake colonization from Iceland) or by refugial bottlenecking during the Ancylus phase of the Baltic Basin after a direct connection to the White Sea had been sequestered. Continued genetic drift is emphasized by lower heterozygosity in the ecologically unstable Belt Sea compared to the central Baltic. Allozymes falsify the reduced-mutability hypothesis to explain bradytelic evolution of Priapulida. Regional genetic homogeneity, ample polymorphism, and preference for anoxic black mud qualify H. spinulosus populations as indicators of microevolutionary responses to water circulation regimes or pollution in the Baltic Sea.
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Priapulida: Überlebenskünstler aus dem frühen Paläozoikum
Biologie in unserer Zeit, 1996Co-Authors: Volker StorchAbstract:Es gibt Tiergruppen, die sich im Verlauf der Erdzeitalter rasch entwickelt haben, zum Beispiel die Saugetiere, welche zwar seit der Oberen Trias bekannt sind, sich aber erst im Tertiar, also in den letzten 65 Millionen Jahren, entfalteten. Andere Tiergruppen existieren schon viel langer, und unter den Bilateria geht die Geschichte der Priapuliden besonders weit zuruck: bis ins Kambrium, also uber mehr als 500 Millionen Jahre. In dieser langen Zeit kam wenigstens funfmal ein Massenaussterben Uber die Welt der Organismen, was zum Beispiel Ende des Perms (vor 230 Millionen Jahren) zum Verschwinden der Mehrzahl aller marinen Arten fuhrte, aber all das haben die Priapuliden nicht nur uberstanden, sie haben sich strukturell in dieser Zeit kaum verandert (Abbildung 1).
Rolf Oeschger - One of the best experts on this subject based on the ideXlab platform.
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The body wall of Halicryptus spinulosus (Priapulida) — ultrastructure and changes induced by hydrogen sulfide
Hydrobiologia, 1992Co-Authors: Hans Heinrich Janssen, Rolf OeschgerAbstract:Halicryptus spinulosus (Priapulida) is extraordinarily resistant to hydrogen sulfide. As described previously, the body wall of specimens from oxic and from hydrogen sulfide-contaminated habitats differs strikingly in colour. In the present paper the ultrastructure of the body wall of specimens kept under oxic conditions is described. These findings serve as a reference for changes induced by exposure to hydrogen sulfide. There are marked ultrastructural differences between epidermal and muscular mitochondria exposed to hydrogen sulfide. Epidermal mitochondria of individuals subjected to hydrogen sulfide are often associated with dense granules of unknown composition. Findings are compared with those from other taxa which may encounter hydrogen sulfide in their environment.
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the body wall of halicryptus spinulosus Priapulida ultrastructure and changes induced by hydrogen sulfide
Hydrobiologia, 1992Co-Authors: Hans Heinrich Janssen, Rolf OeschgerAbstract:Halicryptus spinulosus (Priapulida) is extraordinarily resistant to hydrogen sulfide. As described previously, the body wall of specimens from oxic and from hydrogen sulfide-contaminated habitats differs strikingly in colour. In the present paper the ultrastructure of the body wall of specimens kept under oxic conditions is described. These findings serve as a reference for changes induced by exposure to hydrogen sulfide. There are marked ultrastructural differences between epidermal and muscular mitochondria exposed to hydrogen sulfide. Epidermal mitochondria of individuals subjected to hydrogen sulfide are often associated with dense granules of unknown composition. Findings are compared with those from other taxa which may encounter hydrogen sulfide in their environment.
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Histological studies on Halicryptus spinulosus (Priapulida) with regard to environmental hydrogen sulfide resistance
Hydrobiologia, 1991Co-Authors: Rolf Oeschger, Hans Heinrich JanssenAbstract:The priapulid Halicryptus spinulosus has an outstanding resistance to anoxia and hydrogen sulfide, which enables the animal to survive in deteriorating environments. Whole-body staining procedures, as well as light and scanning electron microscopy were used to study structures and mechanisms possibly involved in sulfide detoxification. The cuticle of the trunk is covered by a coat of mucus and bacteria. Within this coat considerable amounts of finely dispersed iron are precipitated, probably as a Fe^2+-compound. It is suggested that the iron functions as a rechargeable buffer against hydrogen sulfide, protecting both the bacteria and the priapulid host. Although this chemical shield may not alone account for long-term protection, it allows the animal to gain time for metabolic adaptations.
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Histological studies on Halicryptus spinulosus (Priapulida) with regard to environmental hydrogen sulfide resistance
Hydrobiologia, 1991Co-Authors: Rolf Oeschger, Hans Heinrich JanssenAbstract:The priapulid Halicryptus spinulosus has an outstanding resistance to anoxia and hydrogen sulfide, which enables the animal to survive in deteriorating environments. Whole-body staining procedures, as well as light and scanning electron microscopy were used to study structures and mechanisms possibly involved in sulfide detoxification.
Junyuan Chen - One of the best experts on this subject based on the ideXlab platform.
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community palaeoecology of the early cambrian maotianshan shale biota ecological dominance of priapulid worms
Palaeogeography Palaeoclimatology Palaeoecology, 2008Co-Authors: Stephen Q Dornbos, Junyuan ChenAbstract:Abstract The early Cambrian soft-bodied Maotianshan Shale (Chengjiang) biota of Yunnan Province, China provides a critical glimpse of animal life during the heart of the Cambrian radiation. The Shankou biota is the focus of this current work, and 9963 specimens from it have been examined and tallied. This collection of fossils represents a time-averaged assemblage of unknown duration from a 10-meter thick sequence. The predominantly benthic community recovered from this section is presumably autochthonous. This community was buried through several hundred millimeter to centimeter thick burial events. Only specimens interpreted as buried alive, based on either soft-part preservation or fully articulated skeletons, were counted. Algae were too fragmented to be counted. To avoid including synonymous species, diversity was evaluated at the genus level. A total of 57 genera from 9 phyla, encompassing 14 ecological groups, were found in this assemblage. The results reveal that the three most abundant genera comprise 43.2% of all specimens: the tubiform priapulid worm Paraselkirkia (16.0%), the diminutive priapulid worm Sicyophorus (14.3%), and the brachiopod Heliomedusa (12.9%). No other genera total more than 9% of specimens. At the phylum level, there is an interesting dichotomy between taxonomic diversity and ecological dominance. The arthropods are the most diverse phylum (37% of genera) and rank second in relative abundance of specimens (26.3%). The priapulids, however, with only 17.5% of genera is the most abundant group in the assemblage (43.2%). All other phyla, excluding brachiopods (19.6%), represent only 10.9% of the assemblage. Because of their sheer numerical abundance, this study indicates that priapulid worms may have exerted more influence on energy flow and community structure than other phyla in this particular trophic web. This result contrasts strongly with both traditional views of Maotianshan Shale biota palaeoecology, which often claimed arthropod dominance based solely on taxonomic diversity, and the palaeoecology of modern priapulids, which are relegated to marginal marine settings. This result also demonstrates the importance of collecting quantitative relative abundance data when performing palaeoecological investigations.
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Early Cambrian Food Chain: New Evidence from Fossil Aggregates in the Maotianshan Shale Biota, SW China
Palaios, 2005Co-Authors: Jean Vannier, Junyuan ChenAbstract:Three categories of fossil aggregates are recognized in the Lower Cambrian Maotianshan Shale biota from SW China: (1) elliptical aggregates with randomly distributed exoskeletal remains of typically small- to medium-size bivalved arthropods (e.g., ostracode-like bradoriids, phyllocarid- like waptiids), hyoliths, and trilobites are interpreted as coprolites, possibly produced by anomalocaridids (e.g., waptiid-rich coprolites) and/or unknown epibenthic predators; (2) elongate, ribbon-like aggregates composed of oriented small hyolith shells, interpreted as the feces of infaunal carnivorous worms such as priapulids; and (3) concentric aggregates, typically with a central nucleus (e.g., remains of medusoid eldoniids or bivalved arthropod carapaces) and peripheral exoskeletal fragments, possibly generated by bottom currents whirling around carcasses. These new coprolite data add to morphofunctional information obtained from fossil organisms and indicate that predation occurred at different levels of the water column with: (1) endobenthic predators (diverse priapulid fauna) feeding near the sediment-water interface; (2) epibenthic predators/scavengers (almost exclusively arthropods); (3) predators living in the lower levels of the water column (e.g., anomalocaridids); and (4) mid-water predators exploiting upper levels in the water column (e.g., eldoniids, ctenophores, chaetognaths). Communities living at or close to the water-sediment interface (epibenthic sensu stricto, meiobenthic, and demersal animals) were exposed to a multidirectional predatorial pressure from infaunal, epifaunal, and mid-water predators. Although predation was diverse, nothing indicates that the food chain extended beyond the level of primary carnivores. Animals already had acquired complex behaviors such as hunting (e.g., anomalocaridids, priapulids) and predator avoidance in which sensory systems were involved. The example of theMaotianshan Shale indicates that the burst of anatomical innovations (new body plans) that characterizes the early Cambrian alsowas accompanied by the rapid development of new feeding strategies and by an unprecedented expansion of ecological interactions (prey-predator relationships).
John S. Peel - One of the best experts on this subject based on the ideXlab platform.
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Feeding behaviour of a new worm (Priapulida) from the Sirius Passet Lagerstätte (Cambrian Series 2, Stage 3) of North Greenland (Laurentia)
Palaeontology, 2017Co-Authors: John S. PeelAbstract:Singuuriqia simoni gen. et sp. nov. represents the first record of a priapulid worm from the Sirius Passet Lagerstatte (Cambrian Series 2, Stage 3) of North Greenland (Laurentia). It is defined by ...
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A CORSET-LIKE FOSSIL FROM THE CAMBRIAN SIRIUS PASSET LAGERSTÄTTE OF NORTH GREENLAND AND ITS IMPLICATIONS FOR CYCLONEURALIAN EVOLUTION
2016Co-Authors: John S. PeelAbstract:loriciferan. In addition to the double circlet of 7 plates composing the lorica, Sirilorica carlsbergi new genus, new species also preserves up to six multicuspidate cuticular denticles that are similar in shape to the pharyngeal teeth of priapulid worms, although their location is suggestive of scalids. Whilst traditionally placed as a sister group of priapulid worms within Vinctiplicata (Scalidophora), recent molecular sequence data suggest that loriciferans might be more closely related to nematomorphs. The limited morphological information available from Sirilorica is consistent with this interpretation, placing the Sirius Passet fossil within the total-group of Loricifera, within the Loricifera + Nematomorpha clade
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a corset like fossil from the cambrian sirius passet lagerstatte of north greenland and its implications for cycloneuralian evolution
Journal of Paleontology, 2010Co-Authors: John S. PeelAbstract:A large (maximum length 80 mm), tubular, corset-like problematic fossil from the early Cambrian (Cambrian Series 2, Stage 3) Sirius Passet Lagerstate of North Greenland is interpreted as the lorica of an ancestral loriciferan. In addition to the double circlet of 7 plates composing the lorica, Sirilorica carlsbergi new genus, new species also preserves Up to Six multicuspidate Cuticular denticles that are similar in shape to the pharyngeal teeth of priapulid worms, although their location is suggestive of scalids. Whilst traditionally placed as a sister group Of priapulid worms within Vinctiplicata (Scalidophora), recent molecular sequence data Suggest that loriciferans might be more closely related to nematomorphs. The limited morphological information available from Sirilorica is consistent with this interpretation, placing the Sirius Passet fossil within the total-group of Loricifera, within the Loricifera + Nematomorpha clade.
