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Jens T. Høeg - One of the best experts on this subject based on the ideXlab platform.
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ral ssBioMed CentBMC Biology Open AcceResearch article Remarkable convergent evolution in specialized parasitic
2016Co-Authors: Marcos Pérez-losada, Jens T. HøegAbstract:Background: The Thecostraca are arguably the most morphologically and biologically variable group within the Crustacea, including both suspension feeders (Cirripedia: Thoracica and Acrothoracica) and parasitic forms (Cirripedia: Rhizocephala, Ascothoracida and Facetotecta). Similarities between the metamorphosis found in the Facetotecta and Rhizocephala suggests a common evolutionary origin, but until now no comprehensive study has looked at the basic evolution of these thecostracan groups. Results: To this end, we collected DNA sequences from three nuclear genes [18S rRNA (2,305), 28S rRNA (2,402), Histone H3 (328)] and 41 larval characters in seven facetotectans, five ascothoracidans, three acrothoracicans, 25 rhizocephalans and 39 thoracicans (ingroup) and 12 Malacostraca and 10 Copepoda (outgroup). Maximum parsimony, maximum likelihood and Bayesian analyses showed the Facetotecta, Ascothoracida and Cirripedia each as monophyletic. The better resolved and highly supported DNA maximum likelihood and morphological-DNA Bayesian analysis trees depicted the main phylogenetic relationships within the Thecostraca as (Facetotecta, (Ascothoracida, (Acrothoracica, (Rhizocephala, Thoracica)))). Conclusion: Our analyses indicate a convergent evolution of the very similar and highly reduced slug-shaped stages found during metamorphosis of both the Rhizocephala and the Facetotecta. This provides a remarkable case of convergent evolution and implies that the advanced endoparasitic mode of life known from the Rhizocephala and strongly indicated for the Facetotecta had no common origin. Future analyses are needed to determine whether the most recent common ancestor of the Thecostraca was free-living or some primitive form of ectoparasite
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67 (2) 199 – 217 © Museum für Tierkunde Dresden, eISSN 1864-8312, 25.8.2009 Evolution of Morphology, Ontogeny and Life Cycles within the
2012Co-Authors: Arthropod Systematics, Marcos Pérez-losada, Jens T. Høeg, Gregory A. Kolbasov, Crustacea Thecostraca, Henrik Glenner, Keith A. CrandallAbstract:We use a previously published phylogenetic analysis of the Thecostraca to trace character evolution in the major lineages of the taxon. The phylogeny was based on both molecular (6,244 sites from 18S rna, 28S rna and H3 genes) and 41 larval morphological characters with broad taxon sampling across the Facetotecta (7 spp.), Ascothoracida (5 spp.), and Cirripedia (3 acrothoracican, 25 rhizocephalan and 39 thoracican spp.). Morphological apomorphies are identified in larval morphology for almost all major branches within the Thecostraca. Characters from the cypris larva provide a long suite of apomorphies for the Cirripedia and reinforce the concept that this larva was a prerequisite to the tremendous success of that taxon. The evolution of parasitism, obligatory in three major taxa, is discussed. We conclude that the last common ancestor to the Cirripedia was most likely a suspension feeder, and the advanced metamorphosis and endoparasitism known from the Rhizocephala and strongly indicated for the Facetotecta are the result of convergent evolution. We also discuss reproductive systems, which range from separate sexes, over hermaphrodites combined with a separate male sex (androdioecy), to pure hermaphroditism. It is concluded, as envisaged by Darwin, that the Thecostraca provide excellent opportunities for studyin
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Remarkable convergent evolution in specialized parasitic Thecostraca (Crustacea).
BMC Biology, 2009Co-Authors: Marcos Pérez-losada, Jens T. Høeg, Keith A. CrandallAbstract:The Thecostraca are arguably the most morphologically and biologically variable group within the Crustacea, including both suspension feeders (Cirripedia: Thoracica and Acrothoracica) and parasitic forms (Cirripedia: Rhizocephala, Ascothoracida and Facetotecta). Similarities between the metamorphosis found in the Facetotecta and Rhizocephala suggests a common evolutionary origin, but until now no comprehensive study has looked at the basic evolution of these thecostracan groups. To this end, we collected DNA sequences from three nuclear genes [18S rRNA (2,305), 28S rRNA (2,402), Histone H3 (328)] and 41 larval characters in seven facetotectans, five ascothoracidans, three acrothoracicans, 25 rhizocephalans and 39 thoracicans (ingroup) and 12 Malacostraca and 10 Copepoda (outgroup). Maximum parsimony, maximum likelihood and Bayesian analyses showed the Facetotecta, Ascothoracida and Cirripedia each as monophyletic. The better resolved and highly supported DNA maximum likelihood and morphological-DNA Bayesian analysis trees depicted the main phylogenetic relationships within the Thecostraca as (Facetotecta, (Ascothoracida, (Acrothoracica, (Rhizocephala, Thoracica)))). Our analyses indicate a convergent evolution of the very similar and highly reduced slug-shaped stages found during metamorphosis of both the Rhizocephala and the Facetotecta. This provides a remarkable case of convergent evolution and implies that the advanced endoparasitic mode of life known from the Rhizocephala and strongly indicated for the Facetotecta had no common origin. Future analyses are needed to determine whether the most recent common ancestor of the Thecostraca was free-living or some primitive form of ectoparasite.
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immunocytochemical studies on the naupliar nervous system of balanus improvisus crustacea Cirripedia thecostraca
Arthropod Structure & Development, 2008Co-Authors: Jens T. Høeg, Henrike Semmler, Andreas Wanninger, Gerhard ScholtzAbstract:The nervous system of nauplii of the crustacean taxon Cirripedia was analysed in the species Balanus improvisus Darwin, 1854 using for the first time immunocytochemical staining against serotonin, RFamide and α-tubulin in combination with confocal laser scanning microscopy. This approach revealed a circumoesophageal neuropil ring with nerves extending to the first and second antennae and to the mandibles, all features typical for Crustacea. In addition, RFamidergic structures are present in the region of the thoraco-abdomen. A pair of posterior nerves and a pair of lateral nerves run in anterior-posterior direction and are connected by a thoracic nerve ring and a more posteriorly situated commissure. A median nerve is situated along the ventral side of the thoraco-abdomen. The innervation of frontolateral horns and the frontal filaments are α-tubulin-positive. Several pairs of large neurons in the protocerebrum, along the circumoesophageal connectives and in the mandibular ganglion stain only for serotonin. Due to the almost complete absence of comparable data on the neuroanatomy of early (naupliar) stages in other Crustacea, we include immunocytochemical data on the larvae of the branchiopod, Artemia franciscana Kellogg, 1906 in our analysis. We describe several characteristic neurons in the brains of the nauplius larvae of both species which are also found in decapod larvae and in adult brains of other crustaceans. Furthermore, our data reveal that the naupliar brain of cirripedes is more complex than the adult brain. It is concluded that this ontogenetic brain reduction is related to the sessile life style of adult Cirripedia.
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The Chemoreceptive Lattice Organs in Cypris Larvae Develop from Naupliar Setae (Thecostraca: Cirripedia, Ascothoracida and Facetotecta)
Zoologischer Anzeiger - A Journal of Comparative Zoology, 2003Co-Authors: Alexey V. Rybakov, Jens T. Høeg, Peter Gram Jensen, Gregory A. KolbasovAbstract:Abstract Lattice organs are peculiar chemoreceptors found only in the Crustacea Thecostraca (Facetotecta, Ascothoracida, Cirripedia). In these taxa, five pairs occur in the head shield (carapace) of the terminal larval instar (y-cyprid, ascothoracid larva, cyprid), which is the settlement stage. Lattice organs represent an autapomorphy for the Thecostraca but their evolutionary origin and possible homologues in other Crustacea remain obscure. We have used scanning electron microscopy to describe the setation pattern of the head shield in late nauplii of one species of Ascothoracida, one species of Facetotecta and several species of the Cirripedia Thoracica, Acrothoracica, and Rhizocephala. The naupliar head shield always carries two pairs setae situated anteriorly near the midline. Each of these setae carry a single pore, and positional, structural and ontogenetic evidence show that these setae are homologous in all the examined species and that they represent precursors of the two anterior pairs of lattice organs of the succeeding larval stage, viz., the ascothoracid larva (Ascothoracida), y-cyprid (Facetotecta), and cyprid (Cirripedia). This leads us to infer that lattice organs are among the most highly modified sensilla in all Crustacea and they have in most cases lost all external resemblance to a seta. The nauplii of the Rhizocephala carry an additional three pairs of setae situated more posteriorly on the head shield and they could be precursors of the three posterior pairs of lattice organs. All other species examined lack these posterior setae, except the Facetotecta which have one posteriorly situated pair.
Keith A. Crandall - One of the best experts on this subject based on the ideXlab platform.
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67 (2) 199 – 217 © Museum für Tierkunde Dresden, eISSN 1864-8312, 25.8.2009 Evolution of Morphology, Ontogeny and Life Cycles within the
2012Co-Authors: Arthropod Systematics, Marcos Pérez-losada, Jens T. Høeg, Gregory A. Kolbasov, Crustacea Thecostraca, Henrik Glenner, Keith A. CrandallAbstract:We use a previously published phylogenetic analysis of the Thecostraca to trace character evolution in the major lineages of the taxon. The phylogeny was based on both molecular (6,244 sites from 18S rna, 28S rna and H3 genes) and 41 larval morphological characters with broad taxon sampling across the Facetotecta (7 spp.), Ascothoracida (5 spp.), and Cirripedia (3 acrothoracican, 25 rhizocephalan and 39 thoracican spp.). Morphological apomorphies are identified in larval morphology for almost all major branches within the Thecostraca. Characters from the cypris larva provide a long suite of apomorphies for the Cirripedia and reinforce the concept that this larva was a prerequisite to the tremendous success of that taxon. The evolution of parasitism, obligatory in three major taxa, is discussed. We conclude that the last common ancestor to the Cirripedia was most likely a suspension feeder, and the advanced metamorphosis and endoparasitism known from the Rhizocephala and strongly indicated for the Facetotecta are the result of convergent evolution. We also discuss reproductive systems, which range from separate sexes, over hermaphrodites combined with a separate male sex (androdioecy), to pure hermaphroditism. It is concluded, as envisaged by Darwin, that the Thecostraca provide excellent opportunities for studyin
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Remarkable convergent evolution in specialized parasitic Thecostraca (Crustacea).
BMC Biology, 2009Co-Authors: Marcos Pérez-losada, Jens T. Høeg, Keith A. CrandallAbstract:The Thecostraca are arguably the most morphologically and biologically variable group within the Crustacea, including both suspension feeders (Cirripedia: Thoracica and Acrothoracica) and parasitic forms (Cirripedia: Rhizocephala, Ascothoracida and Facetotecta). Similarities between the metamorphosis found in the Facetotecta and Rhizocephala suggests a common evolutionary origin, but until now no comprehensive study has looked at the basic evolution of these thecostracan groups. To this end, we collected DNA sequences from three nuclear genes [18S rRNA (2,305), 28S rRNA (2,402), Histone H3 (328)] and 41 larval characters in seven facetotectans, five ascothoracidans, three acrothoracicans, 25 rhizocephalans and 39 thoracicans (ingroup) and 12 Malacostraca and 10 Copepoda (outgroup). Maximum parsimony, maximum likelihood and Bayesian analyses showed the Facetotecta, Ascothoracida and Cirripedia each as monophyletic. The better resolved and highly supported DNA maximum likelihood and morphological-DNA Bayesian analysis trees depicted the main phylogenetic relationships within the Thecostraca as (Facetotecta, (Ascothoracida, (Acrothoracica, (Rhizocephala, Thoracica)))). Our analyses indicate a convergent evolution of the very similar and highly reduced slug-shaped stages found during metamorphosis of both the Rhizocephala and the Facetotecta. This provides a remarkable case of convergent evolution and implies that the advanced endoparasitic mode of life known from the Rhizocephala and strongly indicated for the Facetotecta had no common origin. Future analyses are needed to determine whether the most recent common ancestor of the Thecostraca was free-living or some primitive form of ectoparasite.
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REANALYSIS OF THE RELATIONSHIPS AMONG THE Cirripedia AND THE ASCOTHORACIDA AND THE PHYLOGENETIC POSITION OF THE FACETOTECTA (MAXILLOPODA: THECOSTRACA) USING 18S rDNA SEQUENCES
Journal of Crustacean Biology, 2002Co-Authors: Marcos Pérez-losada, Jens T. Høeg, Gregory A. Kolbasov, Keith A. CrandallAbstract:Abstract Until now morphological and molecular datasets have failed to agree on phylogenetic relationships within the Crustacea Thecostraca (=Facetotecta, Ascothoracida, and Cirripedia). Three recent phylogenetic studies using 18S ribosomal DNA sequences from selected Cirripedia (Thoracica, Rhizocephala, and Acrothoracica) and Ascothoracida revealed Acrothoracica and Ascothoracida as a monophyletic group. This result disagrees with several larval and spermal morphological features supporting Cirripedia as a monophyletic group. We reanalyzed the same molecular data set including a new Facetotecta sequence using neighbor-joining and maximum likelihood, but incorporating the model of evolution that fits the data best, and maximum parsimony approaches. Our results strongly support the morphological hypothesis that the cirripedes form a monophyletic group, with the Acrothoracica as sister group to the Thoracica + Rhizocephala. Moreover, all the phylogenies showed the Facetotecta as the sister group to the rema...
Marcos Pérez-losada - One of the best experts on this subject based on the ideXlab platform.
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ral ssBioMed CentBMC Biology Open AcceResearch article Remarkable convergent evolution in specialized parasitic
2016Co-Authors: Marcos Pérez-losada, Jens T. HøegAbstract:Background: The Thecostraca are arguably the most morphologically and biologically variable group within the Crustacea, including both suspension feeders (Cirripedia: Thoracica and Acrothoracica) and parasitic forms (Cirripedia: Rhizocephala, Ascothoracida and Facetotecta). Similarities between the metamorphosis found in the Facetotecta and Rhizocephala suggests a common evolutionary origin, but until now no comprehensive study has looked at the basic evolution of these thecostracan groups. Results: To this end, we collected DNA sequences from three nuclear genes [18S rRNA (2,305), 28S rRNA (2,402), Histone H3 (328)] and 41 larval characters in seven facetotectans, five ascothoracidans, three acrothoracicans, 25 rhizocephalans and 39 thoracicans (ingroup) and 12 Malacostraca and 10 Copepoda (outgroup). Maximum parsimony, maximum likelihood and Bayesian analyses showed the Facetotecta, Ascothoracida and Cirripedia each as monophyletic. The better resolved and highly supported DNA maximum likelihood and morphological-DNA Bayesian analysis trees depicted the main phylogenetic relationships within the Thecostraca as (Facetotecta, (Ascothoracida, (Acrothoracica, (Rhizocephala, Thoracica)))). Conclusion: Our analyses indicate a convergent evolution of the very similar and highly reduced slug-shaped stages found during metamorphosis of both the Rhizocephala and the Facetotecta. This provides a remarkable case of convergent evolution and implies that the advanced endoparasitic mode of life known from the Rhizocephala and strongly indicated for the Facetotecta had no common origin. Future analyses are needed to determine whether the most recent common ancestor of the Thecostraca was free-living or some primitive form of ectoparasite
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67 (2) 199 – 217 © Museum für Tierkunde Dresden, eISSN 1864-8312, 25.8.2009 Evolution of Morphology, Ontogeny and Life Cycles within the
2012Co-Authors: Arthropod Systematics, Marcos Pérez-losada, Jens T. Høeg, Gregory A. Kolbasov, Crustacea Thecostraca, Henrik Glenner, Keith A. CrandallAbstract:We use a previously published phylogenetic analysis of the Thecostraca to trace character evolution in the major lineages of the taxon. The phylogeny was based on both molecular (6,244 sites from 18S rna, 28S rna and H3 genes) and 41 larval morphological characters with broad taxon sampling across the Facetotecta (7 spp.), Ascothoracida (5 spp.), and Cirripedia (3 acrothoracican, 25 rhizocephalan and 39 thoracican spp.). Morphological apomorphies are identified in larval morphology for almost all major branches within the Thecostraca. Characters from the cypris larva provide a long suite of apomorphies for the Cirripedia and reinforce the concept that this larva was a prerequisite to the tremendous success of that taxon. The evolution of parasitism, obligatory in three major taxa, is discussed. We conclude that the last common ancestor to the Cirripedia was most likely a suspension feeder, and the advanced metamorphosis and endoparasitism known from the Rhizocephala and strongly indicated for the Facetotecta are the result of convergent evolution. We also discuss reproductive systems, which range from separate sexes, over hermaphrodites combined with a separate male sex (androdioecy), to pure hermaphroditism. It is concluded, as envisaged by Darwin, that the Thecostraca provide excellent opportunities for studyin
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Remarkable convergent evolution in specialized parasitic Thecostraca (Crustacea).
BMC Biology, 2009Co-Authors: Marcos Pérez-losada, Jens T. Høeg, Keith A. CrandallAbstract:The Thecostraca are arguably the most morphologically and biologically variable group within the Crustacea, including both suspension feeders (Cirripedia: Thoracica and Acrothoracica) and parasitic forms (Cirripedia: Rhizocephala, Ascothoracida and Facetotecta). Similarities between the metamorphosis found in the Facetotecta and Rhizocephala suggests a common evolutionary origin, but until now no comprehensive study has looked at the basic evolution of these thecostracan groups. To this end, we collected DNA sequences from three nuclear genes [18S rRNA (2,305), 28S rRNA (2,402), Histone H3 (328)] and 41 larval characters in seven facetotectans, five ascothoracidans, three acrothoracicans, 25 rhizocephalans and 39 thoracicans (ingroup) and 12 Malacostraca and 10 Copepoda (outgroup). Maximum parsimony, maximum likelihood and Bayesian analyses showed the Facetotecta, Ascothoracida and Cirripedia each as monophyletic. The better resolved and highly supported DNA maximum likelihood and morphological-DNA Bayesian analysis trees depicted the main phylogenetic relationships within the Thecostraca as (Facetotecta, (Ascothoracida, (Acrothoracica, (Rhizocephala, Thoracica)))). Our analyses indicate a convergent evolution of the very similar and highly reduced slug-shaped stages found during metamorphosis of both the Rhizocephala and the Facetotecta. This provides a remarkable case of convergent evolution and implies that the advanced endoparasitic mode of life known from the Rhizocephala and strongly indicated for the Facetotecta had no common origin. Future analyses are needed to determine whether the most recent common ancestor of the Thecostraca was free-living or some primitive form of ectoparasite.
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REANALYSIS OF THE RELATIONSHIPS AMONG THE Cirripedia AND THE ASCOTHORACIDA AND THE PHYLOGENETIC POSITION OF THE FACETOTECTA (MAXILLOPODA: THECOSTRACA) USING 18S rDNA SEQUENCES
Journal of Crustacean Biology, 2002Co-Authors: Marcos Pérez-losada, Jens T. Høeg, Gregory A. Kolbasov, Keith A. CrandallAbstract:Abstract Until now morphological and molecular datasets have failed to agree on phylogenetic relationships within the Crustacea Thecostraca (=Facetotecta, Ascothoracida, and Cirripedia). Three recent phylogenetic studies using 18S ribosomal DNA sequences from selected Cirripedia (Thoracica, Rhizocephala, and Acrothoracica) and Ascothoracida revealed Acrothoracica and Ascothoracida as a monophyletic group. This result disagrees with several larval and spermal morphological features supporting Cirripedia as a monophyletic group. We reanalyzed the same molecular data set including a new Facetotecta sequence using neighbor-joining and maximum likelihood, but incorporating the model of evolution that fits the data best, and maximum parsimony approaches. Our results strongly support the morphological hypothesis that the cirripedes form a monophyletic group, with the Acrothoracica as sister group to the Thoracica + Rhizocephala. Moreover, all the phylogenies showed the Facetotecta as the sister group to the rema...
Jorge Angulovaldes - One of the best experts on this subject based on the ideXlab platform.
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dos nuevos registros de crustaceos asociados a la piel del manati trichechus manatus chordata mammalia sirenia de la region noroccidental de cuba two new reports of crustaceans associated to the manatee trichechus manatus chordata mammalia sireni
Revista de Investigaciones Marinas, 2014Co-Authors: Manuel Ortiz, Anmari Alvarezaleman, Jorge AngulovaldesAbstract:Se presentan dos especies de crustaceos asociados a la piel del manati Trichechus manatus, en una localidad de la costa noroccidental cubana. Un cirripedio del genero Chelonibia (Cirripedia, Sessillia) y un tanaidaceo del genero Sinelobus (Crustacea, Peracarida) son registrados por primera vez para las aguas cubanas. Tambien la aparicion de un tanaidaceo asociado a la piel de un manati constituye el primer registro, en Cuba. De ambas especies se presentan, ademas, algunos datos de su biologia y varias figuras. Ademas, se registra la presencia de espiculas calcareas clavadas en la piel del manati. Palabras clave : nuevos registros; crustaceos; Trichechis manatus; ASW, Cuba. ABSTRACT Two crustaceans species associated to the skin of the manatee Trichechus manatus in a locality at north-western Cuba are presented. One barnacle of the genus Chelonibia (Cirripedia, Sessilia) and a tanaid shrimp of the genus Sinelobus (Crustacea, Paracarida) are herein recorded for the first time for the Cuban waters, The finding of a tanaid shrimp on the manatee skin, is a new Cuban record, as well. Some ecological data of both species and figures are also given. The first record of some calcareous spicules nailed in the manatee skin, are also pointed out. Key words: nuevos registros; crustaceos; Trichechis manatus; ASW, Cuba.
Tove M. Gabrielsen - One of the best experts on this subject based on the ideXlab platform.
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DNA barcoding of Cirripedia larvae reveals new knowledge on their biology in Arctic coastal ecosystems
Hydrobiologia, 2019Co-Authors: Katarzyna S. Walczyńska, Janne E. Søreide, Agata Weydmann-zwolicka, Marta Ronowicz, Tove M. GabrielsenAbstract:Pelagic larvae of benthic organisms comprise a substantial part of the coastal Arctic zooplankton community in spring–summer. We studied the timing, growth, and pelagic duration of Cirripedia larvae in Adventfjorden, a high-Arctic fjord in Spitsbergen, Svalbard. Two distinct abundance peaks were found: one in early May (~ 25.000 ind. m^−3) and another one in late May (~ 35,580 ind m^−3). DNA barcoding based on the COI gene was used to identify the barnacle larvae to species. Whereas both Balanus balanus and Semibalanus balanoides were present, the first one dominated (50–100%) the barnacle abundance. High resolution sampling and size measurements of Cirripedia larvae revealed that these larvae most likely originated from a single spawning event. Development of the larvae suggested a pelagic residence time of roughly 2 months for B. balanus and at least 1 month for S. balanoides in the Arctic. Long pelagic residence time, large potential for biofouling on ships and larger plastic debris, combined with the disappearance of landfast sea ice and less ice scouring opens up new opportunities for barnacles to colonize the high-Arctic littoral zone. In a future warmer Arctic, we therefore expect establishment of new, more temperate Cirripedia species in Svalbard.