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Marta Riutort - One of the best experts on this subject based on the ideXlab platform.

  • Phylogeny and biogeography of the Cavernicola (Platyhelminthes: Tricladida): Relicts of an epigean group sheltering in caves?
    Molecular phylogenetics and evolution, 2019
    Co-Authors: Lisandra Benítez-Álvarez, Ronald Sluys, Ana Maria Leal-zanchet, Alejandro Oceguera-figueroa, Rodrigo Lopes Ferreira, Diego De Medeiros Bento, João Alberto Leão Braccini, Marta Riutort
    Abstract:

    The planarian suborder Cavernicola Sluys, 1990 was originally created to house five species of triclad flatworms with special morphological features and a surprisingly discontinuous and broad geographic distribution. These five species could not be accommodated with any degree of certainty in any of the three taxonomic groups existing at that moment, viz., Paludicola Hallez, 1892, Terricola Hallez, 1892, and Maricola Hallez, 1892. The scarce representation of the group and the peculiarities of the morphological features of the species, including several described more recently, have complicated new tests of the monophyly of the Cavernicola, the assessment of its taxonomic status, as well as the resolution of its internal relationships. Here we present the first molecular study including all genera currently known for the group, excepting one. We analysed newly generated 18S and 28S rDNA data for these species, together with a broad representation of other triclad flatworms. The resulting phylogenetic trees supported the monophyly of the Cavernicola, as well as its sister-group relationship to the Maricola. The sister-group relationship to the Maricola and affinities within the Cavernicola falsify the morphology-based phylogeny of the latter that was proposed previously. The relatively high diversity of some Cavernicolan genera suggests that the presumed rarity of the group actually may in part be due to a collecting artefact. Ancestral state reconstruction analyses suggest that the ancestral habitat of the group concerned epigean freshwater conditions. Our results point to an evolutionary scenario in which the Cavernicola (a) originated in a freshwater habitat, (b) as the sister clade of the marine triclads, and (c) subsequently radiated and colonized both epigean and hypogean environments. Competition with other planarians, notably members of the Continenticola, or changes in epigean habitat conditions are two possible explanations -still to be tested- for the loss of most epigean diversity of the Cavernicola, which is currently reflected in their highly disjunct distributions.

  • A molecular analysis of the phylogenetic position of the suborder Cavernicola within the Tricladida (Platyhelminthes), with the description of a new species of stygobiont flatworm from Benin
    Zoological Journal of the Linnean Society, 2016
    Co-Authors: Abdel Halim Harrath, Lamjed Mansour, Moïssou Lagnika, Ronald Sluys, Claude Boutin, Saleh Alwasel, Arnau Poch, Marta Riutort
    Abstract:

    This paper presents a new species of Cavernicolan planarian from the African continent, which enabled us to determine the position of the suborder Cavernicola within the order Tricladida on a molecular basis. A recent paper suggested a sister-group relationship between Cavernicola and marine triclads. However, our work is the first molecular study to demonstrate unequivocally that the Cavernicola does not group with either the freshwater planarians or the land planarians, i.e. is not closely related to the suborder Continenticola, and corroborates the suggested sister-group relationship with the marine triclads or Maricola. Two possible scenarios are proposed for the evolution of the Cavernicola from marine ancestors. The new species is assigned to the genus Novomitchellia and is characterized by the absence of eyes. Testicular follicles are numerous and only dorsal, extending from behind the ovaries to the posterior end of the body. The vasa deferentia separately penetrate the penis bulb and the seminal vesicle. The penis papilla is very short and blunt, and the penis bulb musculature is weak. A long and narrow copulatory bursa is situated behind the gonopore. The common oviduct is orientated perpendicularly to the short bursal canal.

  • A robust molecular phylogeny of the Tricladida (Platyhelminthes: Seriata) with a discussion on morphological synapomorphies
    Proceedings of The Royal Society B: Biological Sciences, 1998
    Co-Authors: Salvador Carranza, D. T. J. Littlewood, K. A. Clough, Iñaki Ruiz-trillo, Jaume Baguñà, Marta Riutort
    Abstract:

    The suborder Tricladida (Platyhelminthes: Turbellaria, Seriata) comprises most well–known species of free–living flatworms. Four infraorders are recognized: (i) the Maricola (marine planarians); (ii) the Cavernicola (a group of primarily Cavernicolan planarians); (iii) the Paludicola (freshwater planarians); and (iv) the Terricola (land planarians). The phylogenetic relationships among these infraorders have been analysed using morphological characters, but they remain uncertain. Here we analyse the phylogeny and classification of the Tricladida, with additional, independent, molecular data from complete sequences of 18S rDNA and 18S rRNA. We use maximum parsimony and neighbour–joining methods and the characterization of a unique gene duplication event involving the Terricola and the dugesiids to reconstruct the phylogeny. The results show that the Maricola is monophyletic and is the primitive sister group to the rest of the Tricladida (the Paludicola plus the Terricola). The Paludicola are paraphyletic since the Terricola and one paludicolan family, the Dugesiidae, share a more recent common ancestor than the dugesiids with other paludicolans (dendrocoelids and planariids). A reassessment of morphological evidence may confirm the apparent redundancy of the existing infraorders Paludicola and Terricola. In the meantime, we suggest replacing the Paludicola and Terricola with a new clade, the Continenticola, which comprises the families Dugesiidae, Planariidae, Dendrocoelidae and the Terricola.

Li-bing Zhang - One of the best experts on this subject based on the ideXlab platform.

  • Polystichum recavum (subg. Haplopolystichum ; Dryopteridaceae), a new cave fern from Guangxi, China
    Phytotaxa, 2018
    Co-Authors: Hong-jin Wei, Li-bing Zhang
    Abstract:

    A new species of Polystichum (subg. Haplopolystichum ; Dryopteridaceae), P. recavum , is described from a limestone cave from southern Guangxi, China. Polystichum recavum is most similar to P. Cavernicola in having oblanceolate lamina and oblong pinnae, but distinguishable from the latter in number of sterile pinna pairs, shape of pinna apex, and shape of the auricles.

  • Polystichum tiandengense (subg. Haplopolystichum; Dryopteridaceae), a New Cave Fern from Guangxi, China
    Novon: A Journal for Botanical Nomenclature, 2017
    Co-Authors: Li-bing Zhang
    Abstract:

    A new fern species, Polystichum tiandengense H. He & Li Bing Zhang (Dryopteridaceae), is described and illustrated from a limestone cave in the Guangxi Zhuangzu Autonomous Region, South China. Polystichum tiandengense is most similar to P. Cavernicola Li Bing Zhang & H. He in having oblong to square pinnae with undulate margins, but the new species is distinguished by its pinnae mostly adjacent to each other or imbricating, and mostly sterile (vs. distant from each other and mostly fertile in P. Cavernicola). Polystichum tiandengense is considered to be Critically Endangered (CR), based on IUCN Red List criteria.

  • Polystichum duyunense (subg. Haplopolystichum ; Dryopteridaceae), a new cave fern from Guizhou, China
    Phytotaxa, 2017
    Co-Authors: Xin-yuan Miao, Li-bing Zhang
    Abstract:

    A new cave fern of Polystichum (subg. Haplopolystichum ; Dryopteridaceae), P. duyunense , is described from a limestone cave in southern Guizhou, China. Polystichum duyunense is most similar to P. Cavernicola in having oblong pinnae, but the former has pinnae larger, often angled basiscopically, and somewhat imbricate, while the latter has pinnae smaller, angled acroscopically, and apart from each other.

  • Polystichum Cavernicola, sp. nov, (sect. Haplopolystichum, Dryopteridaceae) from a karst cave in Guizhou, China and its phylogenetic affinities.
    Botanical Studies, 2011
    Co-Authors: Li-bing Zhang
    Abstract:

    Polystichum Cavernicola L. B. Zhang & H. He, a new pteridophyte species is described and illustrated from a karst cave in southern Guizhou, China. It is a member of Polystichum sect. Haplopolystichum (Dryopteridaceae). A phylogenetic analysis based on the chloroplast trnL-F sequences shows that the new species is most closely related with P speluncicola, a species also described from a karst cave in southern Guizhou. Morphologically, P Cavernicola is most similar to P speluncicola. The important morphological differences between P Cavernicola and P speluncicola include that P Cavernicola has narrow-type microscales on the abaxial laminar surface, its pinnae are chartaceous and have auriculate acroscopic bases, and its lamina is broadest near the midpoint, whereas P speluncicola has broad-type microscales on the abaxial laminar surface, its pinnae are subcoriaceous and have rounded, non-auriculate, acroscopic bases, and its lamina is broadest above the middle. The spores of P. Cavernicola have verrucate sculpturing on the perispore, whereas those of P. speluncicola are cristate with numerous spinules on its perispore. Polystichum Cavernicola is endemic to a single karst cave in southern Guizhou and is considered to be Critically Endangered (CR) based on IUCN Red List criteria.

José Templado - One of the best experts on this subject based on the ideXlab platform.

  • Can a sponge feeder be a herbivore? Tylodina perversa (Gastropoda) feeding on Aplysina aerophoba (Demospongiae)
    Biological Journal of the Linnean Society, 2003
    Co-Authors: Mikel A. Becerro, Xavier Turon, María Jesús Uriz, José Templado
    Abstract:

    Feeding biology in mollusks has important biological, ecological and evolutionary implications because many of the characteristics we observe in mollusks arise from their co-evolution with diet organisms. We investigated the relationship between the opisthobranch Tylodina perversa and the sponges Aplysina aerophoba and Aplysina Cavernicola in order to ascertain the trophic interactions between them. The opisthobranch preferred specimens of Aplysina aerophoba inhabiting shallow overdeep waters, ectosome of Aplysina aerophoba over choanosome, and showed no preference for Aplysina Cavernicola . The sponge Aplysina Cavernicola lacks the cyanobacteria abundant in the ectosome of Aplysina aerophoba . Our study shows that the opisthobranch Tylodina perversa actively selects for sponges or sponge zones with high concentration of cyanobacteria, i.e. only a fraction of the ingested material is of animal origin. Addition of cyanobacteria to symbiont-free sponge material induced a shift in mollusk preference. Our results cast doubt over the widely recognized qualification of Tylodina perversa as a carnivorous sponge feeder and show evidence that cyanobacteria determine the opisthobranch food selection. Whether this is an isolated example of how symbionts may determine trophic interactions between hosts and predators or it is widespread in benthic organisms remains an open question that requires further investigation. © 2003 The Linnean Society of London . Biological Journal of the Linnean Society , 2003, 78 , 429‐438. ADDITIONAL KEYWORDS: Aplysinid sponges ‐ predator‐prey interactions ‐ sponge/microsymbiont/ opisthobranch co-evolution ‐ trophic relationships.

Peter Proksch - One of the best experts on this subject based on the ideXlab platform.

  • The Skeletal Amino Acid Composition of the Marine Demosponge Aplysina Cavernicola
    Marine Drugs, 2014
    Co-Authors: Susanne Ueberlein, Susanne Machill, Hendrik Niemann, Peter Proksch, Eike Brunner
    Abstract:

    It has been discovered during the past few years that demosponges of the order Verongida such as Aplysina Cavernicola exhibit chitin-based skeletons. Verongida sponges are well known to produce bioactive brominated tyrosine derivatives. We could recently demonstrate that brominated compounds do not exclusively occur in the cellular matrix but also in the skeletons of the marine sponges Aplysina Cavernicola and Ianthella basta. Our measurements imply that these yet unknown compounds are strongly, possibly covalently bound to the sponge skeletons. In the present work, we determined the skeletal amino acid composition of the demosponge A. Cavernicola especially with respect to the presence of halogenated amino acids. The investigations of the skeletons before and after MeOH extraction confirmed that only a small amount of the brominated skeleton-bound compounds dissolves in MeOH. The main part of the brominated compounds is strongly attached to the skeletons but can be extracted for example by using Ba(OH)2. Various halogenated tyrosine derivatives were identified by GC-MS and LC-MS in these Ba(OH)2 extracts of the skeletons.

  • Depth profile of Aplysina ssp.: morphological, histological and biochemical aspects and their role in species distinction
    Marine Biodiversity, 2009
    Co-Authors: Anne Klöppel, Annika Putz, Martin Pfannkuchen, Gisela Fritz, Andrej Jaklin, Peter Proksch, Franz Brümmer
    Abstract:

    In the Mediterranean Sea, two species of the genus Aplysina Nardo, 1834 (Demospongiae, Verongida, Aplysinidae) co-occur, both described by Schmidt in 1862 . The first one was named Aplysina aerophoba (formerly Verongia aerophoba ) due to the change of its bright yellow pigment uranidine to dark blue when exposed to air. The second one was named Aplysina Cavernicola (formerly Verongia Cavernicola ) due to its preferred shaded habitats, e.g., caves. The definition for species differentiation was mainly based on ecological and morphological characteristics. However, as both species display a high degree of phenotypic variability, distinction solely based on morphological attributes is not suitable in all cases. In addition, differences can be found in the species-specific microbial composition of symbionts and metabolite pattern. For the first time, we report an investigation on both Aplysina species along one single transect on an underwater slope in the Adriatic Sea, and the successful species distinction using solely the different biochemical composition of metabolites.

  • Depth-Related Alkaloid Variation in Mediterranean Aplysina Sponges
    Zeitschrift fur Naturforschung. C Journal of biosciences, 2009
    Co-Authors: Annika Putz, Martin Pfannkuchen, Franz Brümmer, Anne Kloeppel, Peter Proksch
    Abstract:

    Total amounts and patterns of bromoisoxazoline alkaloids of Aplysina sponges from Croatia (Mediterranean Sea) were analyzed along an underwater slope ranging from 1.8 to 38.5 m. Total amounts of alkaloids varied from sample to sample and showed no correlation with depth. In contrast, striking differences of alkaloid patterns were found between sponges from shallow sites (1.8 - 11.8 m) and those collected from deeper sites (11.8 - 38.5 m). Sponges from shallow depths consistently exhibited alkaloid patterns typical for Aplysina aerophoba with aerophobin-2 (2) and isofistularin-3 (3) as main constituents. Sponges from deeper sites (below 11.8 m) resembled Aplysina Cavernicola with aerothionin (4) and aplysinamisin- 1 (1) as major compounds. The typical A. Cavernicola pigment 3,4-dihydroxyquinoline- 2-carboxylic acid (6), however, could not be detected in A. aerophoba sponges but was replaced by the A. aerophoba pigment uranidine (5) which appeared to be present in all sponge samples analyzed. During transplantation experiments sponges from sites below 30 m featuring the A. Cavernicola chemotype of bromoisoxazoline alkaloids were translocated to shallower habitats (10 m). The alkaloid patterns in transplanted sponges were found to be stable over a period of 12 months and unaffected by this change in depth. In a further experiment, clones of Aplysina sponges from shallow depths of 5 - 6 m resembling the A. aerophoba chemotype were either kept in situ under natural light conditions or artificially shaded by excluding photosynthetically active radiation (PAR). Neither 4 nor 1 were detected in artificially shaded sponges over an observation period of 12 months. In summary, two chemically distinct types of Aplysina sponges were discovered in this study that proved to be remarkably stable with regard to the bromoisoxazoline patterns and unaffected either by changing the light conditions or depth. It is not clear presently whether the Aplysina sponges collected from depths < 11.8 m represent a new chemotype of A. Cavernicola lacking the pigment 6 or whether we have incidentally come across a so far undescribed species of the genus Aplysina.

  • Chemical defense of Mediterranean sponges Aplysina Cavernicola and Aplysina aerophoba.
    Zeitschrift fur Naturforschung. C Journal of biosciences, 2004
    Co-Authors: Carsten Thoms, Matthias Wolff, K. Padmakumar, Rainer Ebel, Peter Proksch
    Abstract:

    The Mediterranean sponges Aplysina aerophoba and A. Cavernicola accumulate brominated isoxazoline alkaloids including aplysinamisin-1 (1), aerophobin-2 (2), isofistularin-3 (3) or aerothionin (4) at concentrations up to 10% of their respective dry weights. In laboratory feeding experiments employing the polyphagous Mediterranean fish Blennius sphinx crude extracts of both Aplysina sponges were incorporated into artificial fish food at their physiological concentrations (based on volume) and offered to B. sphinx in choice feeding experiments against untreated control food. In addition to the Aplysina sponges, extracts from nine other frequently occurring Mediterranean sponges were likewise included into the experiments. Both Aplysina species elicited strong feeding deterrence compared to the other sponges tested. Bioassay-guided fractionation of A. Cavernicola yielded the isoxazoline alkaloids aerothionin (4) and aplysinamisin-1 (1) as well as the 3,4-dihydroxyquinoline-2-carboxylic acid (8) as major deterrent constituents when tested at their physiological concentrations as present in sponges. Aeroplysinin-1 (5) and dienone (6), however, which are formed in A. aerophoba and A. Cavernicola from isoxazoline precursors through bioconversion reactions upon tissue injury showed no or only little deterrent activity. Fractionation of a crude extract of A. aerophoba yielded aerophobin-2 (2) and isofistularin-3 (3) as major deterrent constituents against B. sphinx. We propose that the isoxazoline alkaloids 1-4 of Mediterranean Aplysina sponges as well as the 3,4-dihydroxyquinoline-2-carboxylic acid (8) (in the case of A. Cavernicola) act as defensive metabolites against B. sphinx and possibly also against other predators while the antibiotically active bioconversion products aeroplysinin-1 (5) and dienone (6) may protect sponges from invasion of bacterial pathogens.

  • Sequestration of dietary alkaloids by the spongivorous marine mollusc Tylodina perversa.
    Zeitschrift fur Naturforschung. C Journal of biosciences, 2003
    Co-Authors: Carsten Thoms, Rainer Ebel, Ute Hentschel, Peter Proksch
    Abstract:

    Specimens of the spongivorous Mediterranean opisthobranch Tylodina perversa that had been collected while feeding on Aplysina acerophoba were shown to sequester the brominated isoxazoline alkaloids of their prey. Alkaloids were stored in the hepatopancreas, mantle tissues, and egg masses in an organ-specific manner. Surprisingly, the known sponge alkaloid aerothionin which is found only in A. Cavernicola but not in A. aerophoba was also among the metabolites identified in wild caught specimens of T. perversa as well as in opisthobranchs with a documented feeding history on A. aerophoba. Mollusc derived aerothionin is postulated to be derived from a previous feeding encounter with A. Cavernicola as T. perversa was found to freely feed on both Aplysina sponges in aquarium bioassays. The possible ecological significance of alkaloid sequestration by T. perversa is still unknown.

Cardoso Pedro - One of the best experts on this subject based on the ideXlab platform.