Relevant bibliographies by topics / Chaetognathes

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Academic literature on the topic 'Chaetognathes'

Author: Grafiati
Published: 4 June 2021
Last updated: 1 February 2022

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Journal articles on the topic "Chaetognathes"

1

Casenove, David, Taichiro Goto, and Jean Vannier. "Relation between anatomy and lifestyles in Recent and Early Cambrian chaetognaths." Paleobiology 37, no. 4 (2011): 563–76. http://dx.doi.org/10.1666/10030.1.

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The Burgess Shale-type Lagerstätten of the Early Cambrian Maotianshan Shale record an apparently sudden conquest of pelagic niches by ten phyla of metazoans. One of these phyla is Chaetognatha, a group of predatory marine worms. Given their role as major predators in modern planktonic ecosystems, the chaetognaths discovered in the Maotianshan Shale (Yunnan Province, South China) suggest that the pelagos at the time was already quite complex. Modern chaetognaths, however, can be divided into benthic and pelagic forms; the pelagic nature of Eognathacantha ercainella should therefore be validated by strong morphological evidence.Knowing that planktonic animals present morphological adaptations that increase their buoyancy, we studied the drag produced during the active phase of chaetognath locomotion for the modern forms Paraspadella gotoi (benthic) and Sagitta elegans (pelagic). By using a motion model developed by Jordan in 1992, we could calculate the resistive force produced by the undulatory movement of chaetognaths' bodies.This mechanistic approach evaluates the effect of three motion parameters (relative speed, total length, and tail ratio) on the drag force produced during locomotion. Our results show that the increase of size contributes to higher drag while the shorter tail of the pelagic form balances this effect by reducing the wetted surface subject to friction. For chaetognaths, therefore, a bigger body (both in length and width) and a shorter tail indicate a pelagic lifestyle, a finding that can be applied to the study of the fossil Eognathacantha ercainella. A discriminant analysis can confirm that the Early Cambrian chaetognath presents a pelagic morphology with similarities to modern bathypelagic and mesopelagic species.
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Webb, Wesley H., and Mary A. Sewell. "Year-round maturity of the chaetognath Aidanosagitta regularis in the Hauraki Gulf, New Zealand." Marine and Freshwater Research 66, no. 9 (2015): 852. http://dx.doi.org/10.1071/mf14279.

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The reproductive biology of planktonic chaetognaths is poorly known, particularly with regard to the importance of seasonal factors such as daylength, temperature and lunar phase. We undertook semilunar plankton sampling (March 2013–March 2014) in the Hauraki Gulf, New Zealand, to survey sexual maturity of the abundant chaetognath Aidanosagitta regularis (the only chaetognath species present in sufficient numbers for reproductive study). Contrary to our expectations, breeding of A. regularis appeared unconstrained by seasonal factors, as reproductively mature individuals were available year-round. This finding has implications for embryological study of the chaetognaths.
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Wu, X., K. Li, L. Huang, J. Yin, and Y. Tan. "Seasonal and spatial distribution of chaetognaths on the north-west continental shelf of the South China Sea." Journal of the Marine Biological Association of the United Kingdom 94, no. 4 (January 16, 2014): 837–46. http://dx.doi.org/10.1017/s0025315413001823.

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The seasonal variation and spatial distribution of chaetognaths were studied based on samples collected from July to August 2006 (summer), December 2006 to January 2007 (winter), and in April 2007 (spring) on the north-west continental shelf of the South China Sea. A total of 19 species of chaetognaths were identified. The average chaetognath abundances (mean ±SD) were 54.0 ± 44.5, 36.8 ±16.7 and 48.9 ± 95.5 ind. m−3 in summer, winter and spring, respectively. Flaccisagitta enflata and Serratosagitta pacifica were the dominant species during the whole sampling period, and F. enflata determined the spatial distribution of total chaetognath abundance. According to the topography and hydrological conditions, the survey area was divided into three sub-regions: inshore waters of the western Guangdong (Region I), inshore waters to the east of Hainan Island (Region II) and offshore waters from the western Guangdong to Hainan Island (Region III). The community structure and abundance distribution of chaetognaths varied significantly between the three sub-regions. The species richness was significantly different among the three sub-regions, with the lowest in Region I and the highest in Region III. The species richness was correlated positively with temperature and salinity. The abundance of chaetognaths was significantly higher in Region I than in both Regions II and III in summer and spring. The increasing food availability caused by the cold eddy, coastal upwelling and the western Guangdong coastal current was able support a greater abundance of chaetognaths during warm seasons on the north-west continental shelf of the South China Sea.
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Noblezada, Mary Mar P., and Wilfredo L. Campos. "Chaetognath assemblages along the Pacific Coast and adjacent inland waters of the Philippines: relative importance of oceanographic and biological factors." ICES Journal of Marine Science 69, no. 3 (January 20, 2012): 410–20. http://dx.doi.org/10.1093/icesjms/fsr209.

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Abstract Noblezada, M. M. P., and Campos, W. L. 2012. Chaetognath assemblages along the Pacific Coast and adjacent inland waters of the Philippines: relative importance of oceanographic and biological factors. – ICES Journal of Marine Science, 69: 410–420. When studying plankton distribution, it is necessary to investigate the biology of the target organisms and the surrounding physical environment. Station and species groupings are only useful if they provide insight into the environmental associations of the species in the group. The study covers two geographic regions: the Pacific Coast (Bicol Shelf) and inland waters (San Bernardino Strait, Ticao Pass, Sibuyan, and Visayan Seas) of the Philippines. Comprehensive information is provided on chaetognath assemblages and distribution within the regions. The findings are integrated with oceanographic conditions and phenomena that define the characteristics of the subareas and consideration given to how these conditions affect chaetognath ecology. A comparison is also provided of the community structure of the two regions, and the possible use of chaetognaths as indicator species of water mass movement and oceanographic phenomena explored. In all, 28 284 specimens were examined, and 33 species from 17 genera were identified. Chaetognath distributions, abundance, and community structure were analysed using dissimilarity indices and multiple regression. The results show that the distribution of chaetognaths agrees well with the movement of oceanic water from the Pacific into the central part of the archipelago.
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Batistić, Mirna, Josip Mikuš, and Jakica Njire. "Chaetognaths in the South Adriatic: vertical distribution and feeding." Journal of the Marine Biological Association of the United Kingdom 83, no. 6 (December 2003): 1301–6. http://dx.doi.org/10.1017/s0025315403008713.

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Feeding and vertical distribution of pelagic chaetognaths were studied at coastal and open-sea stations in the northern part of the South Adriatic Pit during five cruises from April 1993 to February 1995. Chaetognaths were more numerous in the upper 100 m, decreased conspicuously with depth, and were captured only rarely between 600 and 1000 m. Copepods were the main food for the most abundant species in all layers. Cannibalism was evident in all species. Feeding on fertilized chaetognath eggs by Pseudosagitta lyra and Mesosagitta decipiens is reported for the first time. The food containing ratio (FCR) and number of prey items per chaetognath (NPC) of Flaccisagitta enflata were highest during the reproductive period. Higher FCRs and NPCs for M. decipiens and P. lyra were noted below 100 m, where the contribution of older specimens increased with depth and the abundance of copepods decreased.
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PETER, Sam, Manoj Kumar BHASKARAN NAIR, and Devika PILLAI. "Evolutionary analyses of phylum Chaetognatha based on mitochondrial cytochrome oxidase I gene." TURKISH JOURNAL OF ZOOLOGY 44, no. 6 (November 20, 2020): 508–18. http://dx.doi.org/10.3906/zoo-2004-18.

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Chaetognaths (arrow worms) are an enigmatic group of transparent planktonic invertebrates and play an important role in the marine food web. Their morphological and developmental features have raised extensive debates since the discovery of the phylum in the 18th century. Uncertainty in the phylogenetic placement of certain chaetognath species still exists and is puzzling many scientists who have tried to clarify this task. Studies using a portion of both small subunit ribosomal ribonucleic acid (SSU rRNA) and large subunit ribosomal ribonucleic acid (LSU rRNA) genes when integrated with conventional taxonomy were contributed to resolve taxonomical issues in this group. Here we present the first phylogenetic study of Chaetognatha based on a portion of mitochondrial cytochrome oxidase I (COI) gene and compare our results with the earlier morphological and molecular evolutionary hypotheses. This study includes 16 extant species, representing 8 genera and 6 of which are among the 9 extant families. We recommend the following clade structure for the phylum: Aphragmophora comprising Sagittidae with Pterosagittidae and Krohnittidae included in the Sagittidae and Phragmophora comprising Eukrohniidae, Spadellidae, and Heterokrohniidae. Phylogenetic analyses also supported the division of Phragmophora into two monophyletic groups: the Monophragmophora and Biphragmophora. Moreover, Ctenodontina/Flabellodontina and Syngonata/Chorismogonata suborders were not validated. Precise phylogenetic investigations using various molecular markers and specimens from diverse regions are definitely needed to provide an exact evolutionary concept on this phylum.
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Fernandes, Luiz Loureiro, José Mauro Sterza, and Keyla de Oliveira Neves. "Seasonal chaetognath abundance and distribution in a tropical estuary (Southeastern, Brazil)." Brazilian Journal of Oceanography 53, no. 1-2 (June 2005): 47–53. http://dx.doi.org/10.1590/s1679-87592005000100005.

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This study focuses on the seasonal variation of the chaetognath species in the Vitória Bay/Passage Channel estuarine system, Espírito Santo, Brazil, in terms of their abundance and distribution. Specimens of chaetognaths were collected between July 1997 and April 1998 at 10 sampling stations, with a cylindrical-conical plankton net of 200 µm mesh and 30 cm mouth, fitted with a mechanical flowmeter. Five chaetognath species were identified: Sagitta enflata, Sagitta decipiens, Sagitta hispida, Sagitta friderici and Sagitta minima. Most of them were distributed in areas of high salinity (e.g. at the stations closest to the outer estuary). The dominant species, S. enflata and S. friderici, were more frequent in the outer estuary where salinities varied from 32 (wet season - summer) to 28 (dry season - winter). S. friderici was the only species found right in the middle of the Passage Channel, at a station close to the main freshwater input into the estuary. Results showed that chaetognaths only enter the estuary due to the tidal effect, and that they are not typical residents of this system. This is to be expected because the group normally inhabits only truly marine regions.
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Bielecka, Luiza, Bartłomiej Jerzak, and Ilona Złoch. "Species composition, seasonal abundance and population structure of chaetognaths in Admiralty Bay (Antarctic)." Polish Polar Research 37, no. 2 (June 1, 2016): 303–24. http://dx.doi.org/10.1515/popore-2016-0017.

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Abstract Although chaetognaths inhabiting polar ecosystems are relatively well known, there are few reports on their functioning in the Antarctic coastal plankton community. The presented results provide the first comprehensive description of population structure of chaetognaths in the neritic zone west of the Antarctic Peninsula. The studies were performed on samples collected in Admiralty Bay, from December 1994 to June 1995. Following six chaetognath species were determined: Eukrohnia hamata, E. bathypelagica, E. fowleri, Pseudosagitta gazellae, P. maxima and Solidosagitta marri. The representatives of Eukrohnia were observed almost throughout the research period, whereas those of Pseudosagitta and Solidosagitta were found only during first four months of our investigation. Eukrohnia hamata showed a strong dominance in respect to abundance (max. 445 ind./1000 m3). The mean abundance of all taxa significantly fluctuated in the study period and across weeks. Generally, all species were represented by the first three maturity stages (I-III), individuals stage IV occurred sporadically, and mature specimens (stage V) were not recorded at all. Morphometric analysis of the most abundant species showed distinct differences in their total length and body proportions. Our findings may suggest that chaetognath populations in Admiralty Bay are migrant, dependent on the inflow of water from the Bransfield Strait, but to prove this statement further, round year study is necessary.
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Kehayias, George. "Quantitative aspects of feeding of chaetognaths in the eastern Mediterranean pelagic waters." Journal of the Marine Biological Association of the United Kingdom 83, no. 3 (April 9, 2003): 559–69. http://dx.doi.org/10.1017/s0025315403007483h.

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The diet of all chaetognath species found in a broad pelagic area of the eastern Mediterranean was investigated through gut content analysis. Eight chaetognath species were recovered from four depth intervals between 0 to 300 m in the Ionian, Cretan and Rhodes Seas and in the Cretan Passage. The mean food containing ratio (FCR) value for all chaetognaths combined was 0·048. Copepods comprised nearly 65% of the total food items consumed. The epipelagic species Sagitta enflata, Sagitta serratodentata atlantica, Sagitta bipunctata and Sagitta minima fed mainly in the 0 to 50 m surface layer, while the mesopelagic species Sagitta lyra, Sagitta decipiens, Sagitta hexaptera and Krohnitta subtilis fed in deeper layers. Sagitta s. atlantica showed the highest mean FCR in the integrated water column (0 to 300 m) of the whole sampling area. The estimated impact of chaetognath predation on copepod communities ranged from 0·3 to 7·8% of the copepod standing stock, and was higher in the Ionian Sea and the Cretan Passage than in the Cretan and Rhodes Seas. Sagitta s. atlantica, S. lyra, and S. decipiens had the most important predation impact among the eight chaetognath species found in the 0 to 50 m, 50 to 100 m and 100 to 300 m depth layers respectively.
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Liang, Tsui Hua, and Luz Amelia Vega-Pérez. "Studies on chaetognaths off Ubatuba region, Brazil. II. Feeding habits." Boletim do Instituto Oceanográfico 43, no. 1 (1995): 35–48. http://dx.doi.org/10.1590/s0373-55241995000100003.

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The diet of chaetognath species were studied by examining the gut contents of 9466 specimens collected off Ubatuba region, São Paulo State. The greatest proportion of chaetognaths (7119 individuals) showed their gut contents empty. Copepods, mollusc eggs, appendicularians, cladocerans and annelids were the most common food items in the gut contents of juveniles and mature stages. Cannibalism occurred in low frequency. In Summer the copepods Temora stylifera and Paracalanus spp were more abundant, whereas Oncaea spp and mollusc eggs were heavily preyed in Winter. There was a clear trend of increasing prey size with the developmental stage.
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Dissertations / Theses on the topic "Chaetognathes"

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Marlétaz, Ferdinand. "Histoire naturelle des chaetognathes : une énigme zoologique à l'ère moléculaire." Thesis, Aix-Marseille 2, 2010. http://www.theses.fr/2010AIX22082.

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Le phylum des chaetognathes constitue une énigme zoologique très ancienne, puisque ses caractéristiques morphologiques et développementales contradictoires ne permettent pas de le classer aisément au sein des animaux bilatériens. Pour tenter de résoudre ce problème, nous avons séquencé une collection d’ESTs pour l’espèce Spadella cephaloptera et développé une approche phylogénomique en utilisant les protéines ribosomiques comme marqueurs et une stratégie originale de taxons composites. Nous avons trouvé que les chaetognathes occupaient une position de groupe frère de tous les autres protostomiens, une position originale qui échappe à la ‘nouvelle vision’ de la phylogénie des animaux et possède des implications pour l’orientation des caractères embryologiques au sein des métazoaires. Nous avons confirmé cette position phylogénétique en nous focalisant sur les gènes Hox des chaetognathes. En outre, nous avons tenté de résoudre l’organisation génomique des gènes Hox de chaetognathes et nous avons rassemblé des éléments qui suggèrent une distribution dispersée des gènes Hox dans le génome. Dans un second temps, une analyse exhaustive des données génomiques accumulées a mis en évidence de nouvelles caractéristiques génomiques inattendues chez les chaetognathes. Nous avons tout d’abord identifié une large duplication génomique caractérisée par un taux élevé de rétention des gènes dupliqués. Nous avons également détecté la présence de trans-splicing pour une fraction importante de transcrits, qui s’accompagne d’une transcription en opéron. Enfin, nous avons découvert un polymorphisme génomique de grande ampleur aux niveaux nucléotidiques et structuraux au sein de la population de référence de Sormiou, dont nous avons démontré qu’il n’était pas lié à un phénomène de spéciation cryptique. Nous avons réalisé une description détaillée de ces variations génétiques dans la région du gène Hox1, où elles sont induites par l’insertion polymorphe d’éléments génétiques mobiles. D’un autre côté, nous avons étudié la diversité génétique mitochondriale dans la population et nous avons identifié plusieurs lignées distinctes, séparées par une divergence moléculaire très élevée et par des remaniements structuraux. L’origine de ce polymorphisme et son impact sur la physiologie et la régulation génique constituent des pistes de recherche prometteuses. Globalement, ce travail a montré qu’au delà de son intérêt comme organisme modèle pour comprendre l’évolution des bilatériens, S. cephaloptera pourrait permettre d’étudier l’impact du polymorphisme génomique sur l’évolution
The chaetognath phylum represents a longstanding zoological conundrum, as its contrasting morphological and developmental characters do not allow a convincing assignment among bilaterian lineages. To tackle this issue, we sequenced ESTs for Spadella cephaloptera and set up a phylogenomic approach based on a ribosomal protein dataset and an original composite taxon strategy. We found that chaetognaths are most likely branched as a protostome sister-group, which challenges ‘new view’ of animal phylogeny and provides insights into the evolution of developmental processes among metazoans. We brought further evidence for this phylogenetic position by focusing on chaetognath Hox genes. We attempted to resolve the genomic organization of the 13 chaetognath genes and we found clues of a dispersed organization. Then, a careful examination of the bulk of genomic data gathered has pointed out new unexpected unusual genomic features of chaetognaths. We identified an extensive gene duplication followed by a high retention of duplicated genes. We also determined that a large part of S. cephaloptera transcripts underwent trans-splicing associated with operonic transcription. Strikingly, we finally uncovered a tremendous genomic polymorphism at both nucleotide and structural levels within the reference population of Sormiou, and showed it is not caused by cryptic speciation. We provided a detailed account of genomic structural variations in the region surrounding Hox1 gene, which have been mediated by polymorphic insertion of mobile genetic elements. Alternatively, we explored the mitochondrial genetic diversity in the population and recovered several divergent mitochondrial lineages, split by phylum-level molecular divergence and structural rearrangments. The origin of this polymorphism as well as its impact on the physiology and genic regulation are challenging questions to think about. As a whole, this work stresses the interest of S. cephaloptera as a model organism, not only to study the evolution of bilaterian body plans, but also the impact of genomic polymorphism on organismal evolution
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Perez, Yvan. "L'appareil digestif des chaetognathes : structure et ultrastructure, aspects fonctionnales et écophysiologiques." Aix-Marseille 1, 1999. http://www.theses.fr/1999AIX11075.

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La structure et l'ultrastructure de l'epithelium digestif de plusieurs genres de chaetognathes (eukrohnia, pterosagitta, sagitta, spadella) temoignent d'une bonne homogeneite. L'epithelium digestif de la region cephalique est constitue de trois types cellulaires secreteurs (s1, s2, s3). La structure fine de leurs grains de secretion suggere une synthese de mucosubstances (s1), d'enzymes (s3) ou des deux a la fois (s2). L'epithelium de l'intestin, situe dans la region du tronc, est compose de deux types cellulaires cilies. Le premier, s4, contient des grains de secretion elaborant probablement la membrane peritrophique et/ou lubrifiant la paroi intestinale. Le second, a, est surtout implique dans une fonction d'absorption et de digestion intracellulaire de macromolecules. Le volume vacuolaire des cellules a varie fortement chez certaines especes mesoplanctoniques du genre sagitta. Chez s. Zetesios et s. Megalophthalma, le degre de vacuolisation est inversement proportionnel au nombre de cellules a hypervacuolisees situees dans les parties laterales de l'epithelium intestinal. Chez s. Minima et s. Decipiens, le volume vacuolaire augmente considerablement, les parties laterales de l'intestin n'etant plus constituees que par deux cellules a ultravacuolisees. La signification ecophysiologique de l'augmentation du volume vacuolaire des cellules a est discutee en fonction de la repartition verticale de plusieurs especes et les vacuoles sont supposees intervenir dans la regulation de la flottabilite. Au cours d'experiences de nutrition realisees chez spadella cephaloptera, les premiers signes de l'activite d'absorption s'observent 5 minutes apres l'ingestion d'une proie avec la presence de vesicules d'endocytose et de vacuoles apicales de type endosome. Durant les etapes suivantes et jusqu'a 10 h apres l'ingestion, se developpe un second type de vacuoles correspondant au compartiment endolysosomal. L'utilisation de traceurs (ferritine, peroxydase) confirme l'implication de ces structures dans les phenomenes d'absorption. Au cours d'un jeune prolonge, l'absorption persiste dans les cellules a, permettant probablement l'internalisation de molecules organiques dissoutes. Parallelement, les cellules s4 presentent des figures de necrose. Apres 1 mois de jeune, la necrose gagne l'ensemble du tissu intestinal et les specimens meurent quelques jour plus tard. La circulation des nutriments a ete envisagee a partir de l'etude des matrices extracellulaires et des cellules epithelio-musculaires peri-intestinales. Les relations morphologiques existant entre le tissu intestinal et ces compartiments suggerent que ceux-ci jouent un role majeur dans le transfert de substances d'origine digestive vers les fluides de la cavite generale. Enfin, en comparant la structure fine des matrices extracellulaires se prolongeant dans le reste du tronc, l'emergence d'un systeme circulatoire vasculaire est discutee.
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Kruse, Svenja [Verfasser]. "Biology of meso- and bathypelagic chaetognaths in the Southern Ocean = Biologie meso- und bathypelagischer Chaetognathen im Südlichen Ozean / Svenja Kruse." Bremerhaven : AWI, Alfred-Wegener-Institut für Polar- und Meeresforschung, 2010. http://d-nb.info/1010200844/34.

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Papillon, Daniel. "Le Modèle chaetognathe : phylogénie et EvoDevo." Aix-Marseille 2, 2004. http://www.theses.fr/2004AIX22097.

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Telford, Maximilian John. "A molecular analysis of chaetognath evolution." Thesis, University of Oxford, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.260778.

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Choe, Nami. "The seasonal biochemical composition of the chaetognath Parasagitta elegans in Conception Bay, Newfoundland in relation to population dynamics and trophodynamics." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0008/MQ52696.pdf.

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Nunes, Rudy Camilo. "Posicionamento filogenético de Chaetognatha baseado em dados morfológicos." Universidade Federal da Paraí­ba, 2010. http://tede.biblioteca.ufpb.br:8080/handle/tede/4111.

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The evolutionary affinities of Chaetognatha were tested under phylogenetic methods and the phylogeny of Deuterostomia was reconstructed. Deuterostomia + Chaetognatha formed the ingroup and Ectoprocta, Brachiopoda, Pterobranchia, Echinodermata, Enteropneusta, Tunicata, Cephalochordata, and Craniata were the terminal taxa, in addition to Chaetognatha. Oweniida, Pogonophora (Frenulata + Vestimentifera), and Phoronida formed the outgroup. The general anatomy of the group was analyzed and, from this process, the most informative characters were selected from the primary literature. The primary homology hypotheses were firstly built and subsequently tested with an appropriate congruence test, the parcimony in this case. Twenty five characters were selected, seventeen are multistate and eight are binary. The character matrix construction and the parcimony analysis were performed with the TNT 1.1 package. All characters were treated how unordered and received identical weights. Just one most parcimonious tree was recovered (length 59, consistence index 0.91 and retention index 0.90). The deuterostome monophyly, plus Chaetognatha, Ectoprocta and Brachiopoda, was recovered. Chaetognatha was recovered most closely related to Craniata, in a terminal position into the cladogram, supported by the characters 082, 16, 202 e 213 e 251 from the Table 4.
As relações evolutivas de Chaetognatha foram testadas com a utilização de métodos filogenéticos e a filogenia de Deuterostomia foi reconstruída. Deuterostomia + Chaetognatha formaram o grupo interno desta análise e os táxons terminais foram Ectoprocta, Brachiopoda, Pterobranchia, Echinodermata, Enteropneusta, Tunicata, Cephalochordata e Craniata, além de Chaetognatha. Como grupos externos foram utilizados os táxons Oweniida, Pogonophora (Frenulata + Vestimentifera) e Phoronida. A anatomia geral do grupo foi analisada e a partir dela foram selecionados os caracteres mais informativos com base na literatura primária. As hipóteses de homologia primária foram primeiramente levantadas e subsequentemente sujeitas a um teste de congruência adequado, que neste caso foi a análise de parcimônia. Foram selecionados 25 caracteres, dos quais 17 são multiestado e 8 são binários. A construção da matriz de caracteres e a análise de parcimônia foi efetuada com auxílio do programa TNT 1.1. Todos os caracteres foram tratados como não ordenados e receberam peso 1 . Foi obtida apenas uma árvore mais parcimoniosa, com tamanho 59, índice de consistência 0.91 e índice de retenção 0.90. A monofilia de Deuterostomia, com a inclusão de Chaetognatha, Ectoprocta e Brachiopoda foi recuperada. Chaetognatha foi recuperado como grupo irmão de Craniata, em uma posição terminal no cladograma, com base nos caracteres 082, 16, 202 e 213 e 251 da Tabela 4.
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Grigor, Jordan. "Ecology and physiology of chaetognaths (semi-gelatinous zooplankton) in Arctic waters." Doctoral thesis, Université Laval, 2017. http://hdl.handle.net/20.500.11794/27614.

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Les chaetognathes sont d’importants membres des communautés mésozooplanctoniques de l’Arctique en ce qui a trait à l'abondance et à la biomasse. Les chaetognathes de l’Arctique se répartissent en trois espèces principales qui sont considérées comme étant strictement carnivores : Eukrohnia hamata, Parasagitta elegans et Pseudosagitta maxima. Cette étude utilise un ensemble de données de filet planctoniques recueillies sur une période de 5 ans dans les régions européennes, canadiennes et de l'Alaska de l’Arctique (2007, 2008, 2012, 2013, 2014) et comprend un cycle annuel complet dans l'Arctique canadien (2007-2008), le but étant d’améliorer notre compréhension sur les distributions, les cycles de vie et les stratégies d'alimentation du E. hamata et du P. elegans. Dans la présente thèse, les points suivants seront abordés : (1) la stratégie d'alimentation et la maturité du P. elegans dans l'Arctique européen durant la nuit polaire en 2012 et 2013, (2) les cycles de croissance et de reproduction, les stratégies d'alimentation et les distributions verticales du E. hamata et du P. elegans dans l'Arctique canadien de 2007 à 2008, et (3) les différences spatiales dans les stratégies d'alimentation du E. hamata et du P. elegans à l'automne 2014. Afin d’étudier leurs stratégies d'alimentation, des analyses de contenu du tube digestif ainsi que des techniques biochimiques ont été utilisées. Dans l'Arctique canadien, le E. hamata et le P. elegans vivent tous deux pendant environ 2 ans. Le P. elegans colonise principalement les eaux épipélagiques, tandis que le E. hamata colonise principalement les eaux mésopélagiques. Dans cette région, P. elegans se reproduit en continue de l'été au début de l'hiver, dans la période de forte biomasse de copépodes, qui constituent ses proies, dans les eaux proches de la surface, un mode de reproduction basé sur l’apport immédiat d’énergie. Cependant, les résultats ont révélé que E. hamata a engendré des couvées distinctes dont on peut voir l’évolution au cours de fenêtres de reproduction séparées, à la fois durant les périodes de printemps-été et d’automne-hiver, ce qui suggère une reproduction basée sur les réserves. Les taux de prédation quotidiens évalués à partir des analyses du contenu du tube digestif sont généralement restés faibles pour les deux espèces de chaetognathes. Toutefois, pour E. hamata et P. elegans, les taux de prédation inférés en été-automne ont dépassé ceux de l’hiver-printemps. Des études d’alimentation ont révélé que E. hamata consomme de la matière organique particulaire (éventuellement des chutes de neige marine) tout au long de l'année, mais surtout en été, alors que le P. elegans se nourrit différemment. Les deux espèces sont caractérisées par une forte croissance estivale. La croissance hivernale du P. elegans était grandement restreinte, tandis que celle du E hamata l’était moindrement. En somme, les différences dans la façon dont les lipides et la neige marine sont utilisés par les deux espèces pourraient expliquer les différences dans leurs cycles de reproduction et leurs patrons de croissance saisonnière.
Chaetognaths are important members of Arctic mesozooplankton communities in terms of abundance and biomass. Despite this, the bulk of seasonal studies have focused on grazing copepods. Arctic chaetognaths comprise three major species which are thought to be strict carnivores: Eukrohnia hamata, Parasagitta elegans and Pseudosagitta maxima. This thesis uses datasets collected from plankton net sampling during five years in European, Canadian and Alaskan areas of the Arctic (2007, 2008, 2012, 2013, 2014) and includes a full annual cycle in the Canadian Arctic (2007-2008), the purpose being to improve our understanding of the distributions, life history and feeding strategies of E. hamata and P. elegans. The following topics are addressed: (1) the feeding strategy and maturity of P. elegans in the European Arctic during the polar night in 2012 and 2013; (2) the growth, breeding cycles, feeding strategies and vertical distributions of E. hamata and P. elegans, in the Canadian Arctic from 2007 to 2008; and (3) spatial differences in the feeding strategies of E. hamata and P. elegans in autumn 2014. To investigate feeding strategies, a combination of gut contents and biochemical techniques was used. In the Canadian Arctic, both E. hamata and P. elegans live for around 2 years. P. elegans mainly colonized epi-pelagic waters, whereas E. hamata mainly colonized meso-pelagic waters. In this region, P. elegans reproduced continuously from summer to early winter when copepod prey peak in near-surface waters. This is characteristic of income breeders. However, results for E. hamata revealed that this species spawned distinct and traceable broods during separate reproductive windows in both spring-summer and autumn-winter, suggesting capital breeding. Daily predation rates inferred from gut content analyses appeared to be generally low in the two chaetognath species, though inferred predation rates in summer-autumn exceeded those in winter-spring. Feeding studies revealed that E. hamata consumed particulate organic matter (possibly falling marine snow) throughout the year but especially in the summer, whereas P. elegans did not feed in this way. High summer growth seems to be a characteristic of both these species. Growth during winter was highly restricted in P. elegans, to a lesser extent in E. hamata. In summary, differences in how lipids and marine snow are utilised by the two species could explain differences in their breeding cycles and seasonal growth patterns.
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MELO, Danielle Caroline da Mota. "Chaetognatha do Arquipélago de Fernando de Noronha (NE, Brasil)." Universidade Federal de Pernambuco, 2015. https://repositorio.ufpe.br/handle/123456789/13831.

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Dentre os principais grupos que compõem o zooplâncton, Chaetognatha é um filo cosmopolita dos mares e oceanos do mundo, reunindo organismos de grande importância ecológica, uma vez que atuam na posição de eficientes predadores, indicadores de áreas pesqueiras e de movimentos de massas d’água. Contudo, apesar de sua clara importância no meio marinho, Chaetognatha é pouco estudado no Oceano Tropical, principalmente em áreas oceânicas do nordeste brasileiro. Esta região é caracterizada pela presença de bancos e ilhas oceânicas, ambientes que podem influenciar diretamente na estrutura das comunidades locais, modificando a distribuição diária e espacial dos organismos. Dentro deste contexto, este estudo foi dividido em dois capítulos, com objetivo de avaliar como o fotoperíodo e a proximidade de Fernando de Noronha influenciam a abundância e a diversidade das espécies de Chaetognatha (I Capítulo); E analisar como a densidade, biomassa e fator de condição das duas espécies mais abundantes comportam-se em Fernando de Noronha, considerando-se seus estágios de desenvolvimento. Para isto, foram estabelecidas duas transecções de amostragem em relação ao fluxo principal da Corrente Sul Equatorial: uma anterior (nordeste) e outra posterior ao arquipélago (sudoeste), cada uma formada por três estações (A, C e E) com coletas diurnas e noturnas. As amostras foram obtidas durante a estação chuvosa (julho/2010), através de arrastos oblíquos de 0-150 m, com redes de plâncton do tipo bongô (500 e 300 m). Em paralelo à coleta de material biológico foram coletados dados abióticos para a caracterização hidrológica. Para o cálculo da biomassa, as medidas do comprimento total das espécies foram obtidas por meio do equipamento ZooScan. Os parâmetros que apresentaram maiores variações na coluna d’água foram a temperatura, oxigênio e fluorescência, enquanto que a salinidade e o pH permaneceram constantes. A comunidade de Chaetognatha foi representada por seis espécies: Serratosagitta serratodentata, Flaccisagitta hexaptera, Flaccisagitta enflata, Flaccisagitta spp., Pterosagitta draco e Ferosagitta hispida, dentre as quais S. serratodentata apresentou a densidade mais elevada (460,46 ± 115,39 ind.m-³). A maioria das espécies foi coletada em números superiores durante o período noturno, e a transecção nordeste reuniu a densidade média mais elevada (56,77 ± 114,71 ind.m-³). As populações das duas espécies mais abundantes, S. serratodentata e F. hexaptera, foram formadas em maior número por indivíduos adultos, que apresentaram maior densidade no período noturno e diurno, respectivamente. A transecção nordeste demonstrou densidades superiores para todos os estágios avaliados. A biomassa média de S. serratodentata foi de 126,61 (± 145 μg.m-³), com os indivíduos adultos contribuindo com 205,47 (± 168,96 μg.m-³) e os juvenis com 47,75 (± 43 μg.m-³); F. hexaptera apresentou uma média de 80,69 (± 336,84 μg.m-³), correspondente a 150,32 (± 464,57 μg.m-³) para os adultos e 4,73 (± 6,34 μg.m-³) para os juvenis. Adultos foram coletados em maioria, com ambas as redes utilizadas. As curvas de crescimento geradas para S. Serratodentata e F. hexaptera indicaram que a primeira espécie converte grande parte de sua energia metabólica na produção de biomassa (b > 3), enquanto que a segunda investe mais no crescimento corpóreo (b < 3). Com exceção de Flaccisagitta spp., os testes estatísticos apontaram que a composição das espécies em Fernando de Noronha é homogênea na faixa de 0-150 m, independentemente do fotoperíodo e da distância do arquipélago (p > 0,05). A biomassa foi significativamente diferente quanto aos adultos de S. serratodentata entre as transecções (U= 6, p= 0,03), o que não foi observado na comparação entre as estações de cada transecção.Em conjunto, estes resultados apontaram a ausência do efeito-ilha sobre Chaetognatha em Fernando de Noronha. A continuação de trabalhos na área de estudo torna-se de suma importância, como forma de avaliar por meio de novas metodologias, a interação das espécies de Chaetognatha com a hidrologia da região.
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Alvarez-Cadena, J. N. "Population dynamics and feeding habits of the chaetognaths Sagitta elegans Verril and Sagitta setosa Mueller in Manx waters, North Irish Sea." Thesis, University of Liverpool, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.384407.

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Books on the topic "Chaetognathes"

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Lutschinger, Sigrid. The marine fauna of New Zealand. [Wellington, N.Z.]: NIWA Oceanographic (NZOI), 1993.

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Kasatkina, A. P. Morfologii︠a︡, sistematika, ėkologii︠a︡ shchetinkocheli︠u︡stnykh I︠A︡ponskogo mori︠a︡ i sopredelʹnykh akvatoriĭ. Vladivostok: Dalʹnauka, 2010.

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Pierrot-Bults, A. C. Chaetognatha: Keys and notes for the identification of the species. London: Published for the Linnean Society of London and the Estuarine and Brackish-Water Sciences Association by E.J. Brill, 1988.

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Pierrot-Bults, Annelies. Chaetognatha. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780199233267.003.0033.

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This chapter describes the taxonomy of Chaetognatha, a small phylum of exclusively marine organisms with approximately 150 species currently recognized, of which about 70 are pelagic. Chaetognatha are also known as arrow worms because of their shape and quick darting movements in the water. The chapter covers their life cycle, ecology, and general morphology. It includes a section that indicates the systematic placement of the taxon described within the tree of life, and lists the key marine representative illustrated in the chapter (usually to genus or family level). This section also provides information on the taxonomic authorities responsible for the classification adopted, recent changes which might have occurred, and lists relevant taxonomic sources.
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Q, Bone, Kapp H, and Pierrot-Bults A. C, eds. The Biology of chaetognaths. Oxford: Oxford University Press, 1991.

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Guglielmo, Letterio, and Adrianna Ianora. Atlas of Marine Zooplankton Straits of Magellan: Amphipods, Euphausiids, Mysids, Ostracods, and Chaetognaths. Springer, 2011.

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(Assistant), T. Antezana, G. Benassi (Assistant), G. Costanzo (Assistant), N. Crescenti (Assistant), I. Ferrari (Assistant), E. Ghirardelli (Assistant), A. Granata (Assistant), et al., eds. Atlas of Marine Zooplankton. Straits of Magellan: Amphipods, Euphausiids, Mysids, Ostracods and Chaetognaths. Springer, 1997.

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Wanninger, Andreas. Evolutionary Developmental Biology of Invertebrates 1: Introduction, Non-Bilateria, Acoelomorpha, Xenoturbellida, Chaetognatha. Springer, 2016.

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Wanninger, Andreas. Evolutionary Developmental Biology of Invertebrates 1: Introduction, Non-Bilateria, Acoelomorpha, Xenoturbellida, Chaetognatha. Springer, 2015.

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(Editor), Frederick W. Harrison, and Edward E. Ruppert (Editor), eds. Microscopic Anatomy of Invertebrates, Hemichordata, Chaetognatha, and the Invertebrate Chordates (Microscopic Anatomy of Invertebrates). Wiley-Liss, 1997.

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Book chapters on the topic "Chaetognathes"

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Ghirardelli, E. "Chaetognaths." In Atlas of Marine Zooplankton Straits of Magellan, 241–68. Berlin, Heidelberg: Springer Berlin Heidelberg, 1997. http://dx.doi.org/10.1007/978-3-642-60340-2_7.

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Harzsch, Steffen, Carsten H. G. Müller, and Yvan Perez. "Chaetognatha." In Evolutionary Developmental Biology of Invertebrates 1, 215–40. Vienna: Springer Vienna, 2015. http://dx.doi.org/10.1007/978-3-7091-1862-7_10.

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Pandian, T. J. "Chaetognatha." In Reproduction and Development in Minor Phyla, 227–32. First edition. | Boca Raton : CRC Press, 2021. | Series:: CRC Press, 2021. http://dx.doi.org/10.1201/9781003057512-31.

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Foster, Laura. "Chaetognaths (Arrowworms)." In Invertebrate Medicine, 355–64. Oxford, UK: Wiley-Blackwell, 2011. http://dx.doi.org/10.1002/9780470960806.ch19.

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Kapp, Helga. "Chaetognatha – Pfeilwürmer." In Stresemann - Exkursionsfauna von Deutschland. Band 1: Wirbellose (ohne Insekten), 641–42. Berlin, Heidelberg: Springer Berlin Heidelberg, 2019. http://dx.doi.org/10.1007/978-3-662-55354-1_23.

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Goto, T., and M. Yoshida. "Nervous System in Chaetognatha." In Nervous Systems in Invertebrates, 461–81. Boston, MA: Springer US, 1987. http://dx.doi.org/10.1007/978-1-4613-1955-9_16.

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Shinn, George L. "TEM Analyses of Chaetognath Reproductive Organs." In Methods in Molecular Biology, 111–23. Totowa, NJ: Humana Press, 2014. http://dx.doi.org/10.1007/978-1-62703-974-1_7.

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Terazaki, Makoto. "Feeding of Carnivorous Zooplankton, Chaetognaths in the Pacific." In Dynamics and Characterization of Marine Organic Matter, 257–76. Dordrecht: Springer Netherlands, 2000. http://dx.doi.org/10.1007/978-94-017-1319-1_13.

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Barthélémy, Roxane-Marie, Michel Grino, Pierre Pontarotti, Jean-Paul Casanova, and Eric Faure. "A Possible Relationship Between the Phylogenetic Branch Lengths and the Chaetognath rRNA Paralog Gene Functionalities: Ubiquitous, Tissue-Specific or Pseudogenes." In Evolutionary Biology from Concept to Application, 155–64. Berlin, Heidelberg: Springer Berlin Heidelberg, 2008. http://dx.doi.org/10.1007/978-3-540-78993-2_9.

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Cole, Theodor C. H. "IV. Plathelminthes (Plattwürmer), Rotatoria (Rädertiere), Nematomorpha (Saitenwürmer), Nemertini (Schnurwürmer), Acanthocephala (Kratzer), Chaetognatha (Pfeilwürmer), Phoronida (Hufeisenwürmer), Gastrotricha (Bauchhärlinge), Enteropneusta (Eichelwürmer), Pterobranchia (Flügelkiemer) – Platyhelminthes (flatworms, tapeworms), Rotatoria (rotifers), Nematomorpha (horsehair worms), Nemertini (nemertines), Acanthocephala (spiny-headed worms), Chaetognatha (arrow worms), Phoronida (phoronids), Gastrotricha (gastrotrichs), Enteropneusta (acorn worms), Pterobranchia (sea angels)." In Wörterbuch der Wirbellosen / Dictionary of Invertebrates, 29–34. Berlin, Heidelberg: Springer Berlin Heidelberg, 2016. http://dx.doi.org/10.1007/978-3-662-52869-3_4.

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