Examinando por Autor "Pardos, Fernando"

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Comparative morphology of serotonergic‐like immunoreactive elements in the central nervous system of kinorhynchs (Kinorhyncha, Cyclorhagida).
(Wiley, 2013-03) Herranz, Maria; Pardos, Fernando; Boyle, Michael J.
Cycloneuralian taxa exhibit similar organ system architectures, providing informative characters of metazoan evolution, yet very few modern comparative descriptions of cellular and molecular homologies within and among those taxa are available. We immunolabeled and characterized elements of the serotonergic nervous system in the kinorhynchs Echinoderes spinifurca, Antygomonas paulae, and Zelinkaderes brightae using confocal laser scanning microscopy. Fluorescent markers targeting DNA were combined with observations of auto-fluorescent structures to guide interpretations of the internal and external anatomy in each species. Results show a common pattern of the central nervous system with a circumenteric brain divided into ring-shaped anterior and posterior neuronal somata and a central neuropil connected to a multi-stringed, longitudinal ventral nerve cord. Structural similarities and differences in the nervous systems of these species were observed and described, stressing the incomplete ring nature of the anterior region of the kinorhynch brain, the functional relationship between the brain and the movable introvert, and the number and arrangement of nerve strings and somata of the ventral nerve cord. The ventral cord ends in two ventrolateral cell bodies in E. spinifurca, and forms a terminal loop associated with a midterminal spine in A. paulae and Z. brightae. The possible functional and phylogenetic significance of these features and arrangements are discussed.
Kinorhyncha from the Iberian Peninsula: new data from the first intensive sampling campaigns
(Magnolia Press, 2012-07-30) Herranz, Maria; Sánchez, Nuria; Benito, Jesús; Pardos, Fernando
Data are presented from the first intensive sampling of Kinorhyncha around the Iberian Peninsula over a 21-year periodfrom 1990 to 2011, from 81 sites mostly in less than 100 m water depth. Light-microscopic examination of approximately2000 specimens yielded 11 genera and 29 species, only 11 of which were previously recorded from peninsular waters. Thebalance comprises ten new species records for the peninsula and eight new species that are yet to be described. The mostspeciose genus is Echinoderes, with ten species, two of them new, followed by Pycnophyes (nine species, three new).There are two species of Antygomonas (one new), and one each for the genera Campyloderes, Centroderes, Condyloderes(one new), Dracoderes, Meristoderes, Semnoderes, Kinorhynchus (one new), and Paracentrophyes. The most ubiquitousspecies in the samples, appearing at nearly all localities was Pycnophyes dentatus, newly recorded for the Iberian Penin-sula and found at nearly all sampled localities and in high numbers. Echinoderes cantabricus, E. hispanicus and E. dujar-dinii also have a wide distribution along both Atlantic and Mediterranean coasts. Known information on diversity, biogeography and ecology (depth, sediment and abundance) is discussed.
Meristoderes gen. nov., a new kinorhynch genus, with the description of two new species and their implications for echinoderid phylogeny (Kinorhyncha: Cyclorhagida, Echinoderidae).
(Elsevier, 2012-08) Herranz, Maria; Thormar, Jonas; Benito, Jesús; Sánchez, Nuria; Pardos, Fernando
A new kinorhynch genus, Meristoderes gen. nov., and two new species from Spain and the Solomon Islands, respectively, are described. The new genus is distinguished from all other genera by the first segment consisting of a closed cuticular ring, and the second segment having partial tergosternal junctions, and a superficial midventral fold. This is a new cuticular configuration that may shed light into the phylogenetic relationships of echinoderid kinorhynchs. Meristoderes macracanthus gen. et sp. nov. from the Mediterranean coast of Spain is recognised by the presence of middorsal spines on segments 4, 6 and 8, ventrolateral tubules on segment 2, lateroventral tubules on segment 5, lateroventral spines on segments 6–9, lateral accessory tubules on segment 8, one pair of laterodorsal tubules on segment 10. Meristoderes galatheae sp. nov. from the Solomon Islands is recognized by having a middorsal spine on segment 4 only, ventrolateral tubules on segment 2, lateroventral tubules on segment 5, lateroventral spines on segments 6–9, lateral accessory tubules on segment 8 and subdorsal tubules on segment 10. Both species have a pattern of paraventral perforation site clusters on segments 3–9, with conspicuously long bracteate hairs from the posteriormost perforations sites on the segments 3–7 and 3–6, respectively. The new genus Meristoderes gen. nov. is included into the family Echinoderidae Bütschli, 1876 and appears closely related with the genera Cephalorhyncha Adrianov, 1999 and Echinoderes Claparède, 1863. The new information it provides is discussed to clarify the internal phylogeny of Echinoderidae. The terminology for cuticular characters in the overlapping area between consecutive segments is also standardized.
Neuroanatomy of Mud dragons: a comprehensive view of the nervous system in Echinoderes (Kinorhyncha) by confocal laser scanning microscopy.
(Springer, 2019-10) Herranz, Maria; Leander, Brian S.; Pardos, Fernando; Boyle, Michael J.
Background: The Scalidophora (Kinorhyncha, Loricifera and Priapulida) have an important phylogenetic position as early branching ecdysozoans, yet the architecture of their nervous organ systems is notably underinvestigated. Without such information, and in the absence of a stable phylogenetic context, we are inhibited from producing adequate hypotheses about the evolution and diversification of ecdysozoan nervous systems. Here, we utilize confocal laser scanning microscopy to characterize serotonergic, tubulinergic and FMRFamidergic immunoreactivity patterns in a comparative neuroanatomical study with three species of Echinoderes, the most speciose, abundant and diverse genus within Kinorhyncha. Results: Neuroanatomy in Echinoderes as revealed by acetylated α-tubulin immunoreactivity includes a circumpharyngeal brain and ten neurite bundles in the head region that converge into five longitudinal nerves within the trunk. The ventral nerve cord is ganglionated, emerging from the brain with two connectives that converge in trunk segments 2–3, and diverge again within segment 8. The longitudinal nerves and ventral nerve cord are connected by two transverse neurites in segments 2–9. Differences among species correlate with the number, position and innervation of cuticular structures along the body. Patterns of serotoninergic and FMRFamidergic immunoreactivity correlate with the position of the brain neuropil and the ventral nerve cord. Distinct serotonergic and FMRFamidergic somata are associated with the brain neuropil and specific trunk segments along the ventral nerve cord. Conclusions: Neural architecture is highly conserved across all three species, suggesting that our results reveal a pattern that is common to more than 40%of the species within Kinorhyncha. The nervous system of Echinoderes is segmented along most of the trunk; however, posterior trunk segments exhibit modifications that are likely associated with sensorial, motor or reproductive functions. Although all kinorhynchs show some evidence of an externally segmented trunk, it is unclear whether external segmentation matches internal segmentation of nervous and muscular organ systems across Kinorhyncha, as we observed in Echinoderes. The neuroanatomical data provided in this study not only expand the limited knowledge on kinorhynch nervous systems but also establish a comparative morphological framework within Scalidophora that will support broader inferences about the evolution of neural architecture among the deepest branching lineages of the Ecdysozoa.
On the genus Dracoderes Higgins & Shirayama, (1990) (Kinorhyncha: Cyclorhagida) with a redescription of its type species, and a description of a new species from Spain
(Taylor & Francis, 2012-02-06) Sørensen, Martin V.; Herranz, María; Min, Won-Gi; Rho, Hyun Soo; Yamasaki, Hiroshi; Sánchez, Nuria; Pardos, Fernando
The type species of Dracoderes, D. abei, is redescribed based on specimens from several localities in Japan and Korea, and a new species of the genus, Dracoderes gallaicus sp. nov., is described from the coast of Spain in Western Europe. The new species is distinguished by the presence of lateral accessory spines on segment 5. In addition, preliminary diagnostic notes on a yet undescribed species from the Okinawa Region, Dracoderes sp. 1, are provided. Based on new information from D. abei and D. gallaicus sp. nov., an emended genus diagnosis for Dracoderes is proposed. The study includes the first scanning electron microscopical data for species of Dracoderes, and presents for the first time detailed information about head morphology and scalid arrangement, new data about the arrangement of the neck placids, and demonstrates the presence of feebly visible nephridial pores. The new information may be of phylogenetic significance, and is expected to contribute important data for future phylogenetic analyses of the kinorhynch interrelationships.
Phylogeny of Kinorhyncha Based on Morphology and Two Molecular Loci
(Public Library of Science, 2015-07) Sørensen, Martin V.; Dal Zotto, Mateo; Rho, Hyun Soo; Herranz, Maria; Sánchez, Nuria; Pardos, Fernando; Yamasaki, Hiroshi
The phylogeny of Kinorhyncha was analyzed using morphology and the molecular loci 18S rRNA and 28S rRNA. The different datasets were analyzed separately and in combination, using maximum likelihood and Bayesian Inference. Bayesian inference of molecular sequence data in combination with morphology supported the division of Kinorhyncha into two major clades: Cyclorhagida comb. nov. and Allomalorhagida nom. nov. The latter clade represents a new kinorhynch class, and accommodates Dracoderes, Franciscideres, a yet undescribed genus which is closely related with Franciscideres, and the traditional homalorhagid genera. Homalorhagid monophyly was not supported by any analyses with molecular sequence data included. Analysis of the combined molecular and morphological data furthermore supported a cyclorhagid clade which included all traditional cyclorhagid taxa, except Dracoderes that no longer should be considered a cyclorhagid genus. Accordingly, Cyclorhagida is divided into three main lineages: Echinoderidae, Campyloderidae, and a large clade, ‘Kentrorhagata’, which except for species of Campyloderes, includes all species with a midterminal spine present in adult individuals. Maximum likelihood analysis of the combined datasets produced a rather unresolved tree that was not regarded in the following discussion. Results of the analyses with only molecular sequence data included were incongruent at different points. However, common for all analyses was the support of several major clades, i.e., Campyloderidae, Kentrorhagata, Echinoderidae, Dracoderidae, Pycnophyidae, and a clade with Paracentrophyes + New Genus and Franciscideres (in those analyses where the latter was included). All molecular analyses including 18S rRNA sequence data furthermore supported monophyly of Allomalorhagida. Cyclorhagid monophyly was only supported in analyses of combined 18S rRNA and 28S rRNA (both ML and BI), and only in a restricted dataset where taxa with incomplete information from 28S rRNA had been omitted. Analysis of the morphological data produced results that were similar with those from the combined molecular and morphological analysis. E.g., the morphological data also supported exclusion of Dracoderes from Cyclorhagida. The main differences between the morphological analysis and analyses based on the combined datasets include: 1) Homalorhagida appears as monophyletic in the morphological tree only, 2) the morphological analyses position Franciscideres and the new genus within Cyclorhagida near Zelinkaderidae and Cateriidae, whereas analyses including molecular data place the two genera inside Allomalorhagida, and 3) species of Campyloderes appear in a basal trichotomy within Kentrorhagata in the morphological tree, whereas analysis of the combined datasets places species of Campyloderes as a sister clade to Echinoderidae and Kentrorhagata.