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L. J. Newman - One of the best experts on this subject based on the ideXlab platform.
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A new stylochid flatworm (Platyhelminthes, Polycladida) from Victoria, Australia and observations on its biology
Journal of Natural History, 2005Co-Authors: Marsha Merory, L. J. NewmanAbstract:There are only four polyclad flatworms currently known from temperate waters of Victoria, Australia, although these turbellarians are common inhabitants of rocky shores. A new stylochid flatworm, Stylochus pygmaeus sp. nov. (Platyhelminthes, Polycladida) or oyster leech is described here from Port Philip Bay, Victoria. This flatworm was observed feeding on three species of barnacles by extending its pharynx over its prey and extruding copious amounts of mucus. Worms also preferred to prey on larger‐sized barnacles regardless of the species. Further observations indicated that these worms deposited eggs at night inside empty barnacle shells. Each eggmass was brooded for several days with the worms only moving off to feed. Each egg capsule contained multiple embryos and after 5 or 6 days, positively photo‐tactic, four‐lobed Gotte's larvae emerged. Larvae metamorphosed to juvenile flatworms 1–2 weeks post‐hatching but failed to settle and survive.
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A new species of pseudocerotid flatworm (Platyhelminthes, Polycladida) from the Indo-Pacific
2002Co-Authors: L. J. Newman, Peter SchuppAbstract:A new species of pseudocerotid flatworm Pseudoceros indicus nov. sp. (Platyhelminthes, Polycladida) is described. This species was found to be widespread and abundant from Chuuk Lagoon, Micronesia, common from eastern Australia and Papua New Guinea, and rare from the Indian Ocean. There has been much confusion over the name of this and similarly patterned species. Remarks on other pseudo- cerotids from Micronesia are also presented.
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A molecular framework for the phylogeny of the Pseudocerotidae (Platyhelminthes, Polycladida)
Hydrobiologia, 2001Co-Authors: M. K. Litvaitis, L. J. NewmanAbstract:Systematic relationships within the cotylean family Pseudocerotidae were examined using nucleotide sequences of the D3 expansion segment of the 28S rDNA gene. A previously suggested separation of Pseudoceros and Pseudobiceros based on the number of male reproductive systems was confirmed. Regardless of the algorithm employed, Pseudoceros always formed a monophyletic clade. Pseudobiceros appeared to be paraphyletic; however, a constrained maximum parsimony tree was not significantly longer (2 steps, α = 0.05). Additionally, the genera Maiazoon, Phrikoceros and Tytthosoceros were validated as taxonomic entities, and their relationships to other genera within the family were determined. Molecular data also supported species separations based on colour patterns. An intraspecific genetic distance of 1.14% was found for Pseudoceros bifurcus, whereas the intrageneric distance was 3.58%. Genetic distances among genera varied, with the closest distance being 2.048% between Pseudobiceros and Maiazoon, and the largest distance (8.345%) between Pseudoceros and Tytthosoceros.
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A new genus of euryleptid flatworm (Platyhelminthes, Polycladida) from the Indo-Pacific
Journal of Natural History, 2000Co-Authors: L. J. Newman, Lester R. G. CannonAbstract:Five new species and one new combination of marine flatworms belonging to the new genus, Maritigrella nov. gen. (Platyhelminthes, Polycladida, Euryleptidae) are presented here from the Great Barrier Reef, Australia. Additional records are given from Australia, Indonesia and the Republic of the Maldives.
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Taxonomic and biological observations on the tiger flatworm, Maritigrella crozieri (Hyman, 1939), new combination (Platyhelminthes, Polycladida, Euryleptidae) from Florida waters
Journal of Natural History, 2000Co-Authors: L. J. Newman, Jon L. Norenburg, Sherry A. ReedAbstract:The tiger flatworm, Maritigrella crozieri (Hyman, 1939) (Platyhelminthes, Polycladida, Cotylea) new combination, is redescribed from eastern Florida and the Florida Keys. This marine flatworm is one of the most common polyclads within warm temperate to tropical west Atlantic, yet it has been misidentified consistently as a pseudocerotid. Animals were kept alive in the laboratory for 3 weeks for biological observations. Findings indicated that these euryleptids employ hypodermic insemination, with multiple copulations occurring over several days. Sperm was transferred in sperm bundles bilaterally with little apparent damage to the epidermis of the copulating worms. Copulation sessions were variable and lasted an average of 15.4 min. In situ and laboratory observations indicated that M. crozieri fed exclusively on the mangrove ascidian Ecteinascidia turbinata Herdman, 1880, an individual consuming one prey zooid in an average of 17 min and an average of 19 zooids over 24h.
Noreña Carolina - One of the best experts on this subject based on the ideXlab platform.
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Phylogeny of Polycladida (Platyhelminthes) based on mtDNA data
'Springer Science and Business Media LLC', 2019Co-Authors: Aguado, Mª Teresa, Bleidorn Christoph, Noreña Carolina, Marquina Daniel, Brusa Francisco, Damborenea Cristina, Almon Bruno, Alcaraz Lourdes, Grande CristinaAbstract:A phylogenetic analysis of Polycladida based on two partial mitochondrial genes (cox1 and 16S) is provided. The analysis includes 30 polyclad terminals that represent species from the two taxa which traditionally divide the groups Cotylea and Acotylea. Our phylogenetic analyses produced a well-supported hypothesis that confirms the monophyly of Polycladida, as well as Acotylea and Cotylea. Within Acotylea, there are two lineages not highly supported: on one hand, Leptoplanoidea (excluding Hoploplana elisabelloi) and one Stylochoidea member (Pseudostylochus intermedius) (classification sensu Faubel, 1983, 1984), and on the other hand, Stylochoidea members together with Discocelis tigrina and H. elisabelloi. The genera Stylochus and Imogine are not monophyletic. Within Cotylea, Pseudocerotidae and Euryleptidae are monophyletic, though not highly supported, while Prosthiostomidae is not. Euryleptoidea is paraphyletic. The genera Pseudobiceros and Pseudoceros are monophyletic and highly supported. Our results suggest that, within Acotylea, the prostatoid organs of Discocelis may have been derived from a prostatic vesicle. The genus Hoploplana could be included in Stylochoidea. Within Cotylea, the common ancestor of Euryleptidae and Pseudocerotidae might have been an aposematic animal with tentacles.We acknowledge Anna Maria Addamo (MNCN), Agostina Vertino (UNIMIB), Silvia Spezzaferri (UNIFR), Andy Wheeler (UCC) and Commander, crew and scientific party of the Moira Mound EUROFLEETS cruise aboard the Belgica R/V, funded by the European Union Seventh Framework Programme (FP7/2007-2013), under the Eurofleets grant agreement no. 228344.Peer Reviewe
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Characterization of the complete mitochondrial genomes from Polycladida (Platyhelminthes) using next-generation sequencing
'Elsevier BV', 2019Co-Authors: Aguado, Mª Teresa, Grande Cristina, Gerth Michael, Bleidorn Christoph, Noreña CarolinaAbstract:The complete mitochondrial genomes of three polycladids, the acotylean Hoploplana elisabelloi and the cotyleans Enchiridium sp. and Prosthiostomum siphunculus have been assembled with high coverage from Illumina sequencing data. The mt genomes contain 36 genes including 12 of the 13 protein-coding genes characteristic for metazoan mitochondrial genomes, two ribosomal RNA genes, and 22 transfer RNA genes. Gene annotation, gene order, genetic code, start and stop codons and codon bias have been identified. In comparison with the well investigated parasitic Neodermata, our analysis reveals a great diversity of gene orders within Polycladida and Platyhelminthes in general. By analyzing representative genomes of the main groups of Platyhelminthes we explored the phylogenetic relationships of this group. The phylogenetic analyses strongly supported the monophyly of Polycladida, and based on a small taxon sampling suggest the monophyly of Acotylea and Cotylea.CG is currently a “Ramon y Cajal” postdoctoral fellow supported by the Spanish MEC (Ministerio de Economia y Competividad) and the UAM and funded by project no CGL2011-29916.Peer Reviewe
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Probing recalcitrant problems in polyclad evolution and systematics with novel mitochondrial genome resources
'Elsevier BV', 2019Co-Authors: Kenny, Nathan J., Damborenea, Maria Cristina, Noreña Carolina, Grande CristinaAbstract:For their apparent morphological simplicity, the Platyhelminthes or “flatworms” are a diverse clade found in a broad range of habitats. Their body plans have however made them difficult to robustly classify. Molecular evidence is only beginning to uncover the true evolutionary history of this clade. Here we present nine novel mitochondrial genomes from the still undersampled orders Polycladida and Rhabdocoela, assembled from short Illumina reads. In particular we present for the first time in the literature the mitochondrial sequence of a Rhabdocoel, Bothromesostoma personatum (Typhloplanidae, Mesostominae). The novel mitochondrial genomes examined generally contained the 36 genes expected in the Platyhelminthes, with all possessing 12 of the 13 protein-coding genes normally found in metazoan mitochondrial genomes (ATP8 being absent from all Platyhelminth mtDNA sequenced to date), along with two ribosomal RNA genes. The majority presented possess 22 transfer RNA genes, and a single tRNA gene was absent from two of the nine assembled genomes. By comparison of mitochondrial gene order and phylogenetic analysis of the protein coding and ribosomal RNA genes contained within these sequences with those of previously sequenced species we are able to gain a firm molecular phylogeny for the inter-relationships within this clade. Our phylogenetic reconstructions, using both nucleotide and amino acid sequences under several models and both Bayesian and Maximum Likelihood methods, strongly support the monophyly of Polycladida, and the monophyly of Acotylea and Cotylea within that clade. They also allow us to speculate on the early emergence of Macrostomida, the monophyly of a “Turbellarian-like” clade, the placement of Rhabditophora, and that of Platyhelminthes relative to the Lophotrochozoa (=Spiralia). The data presented here therefore represent a significant advance in our understanding of platyhelminth phylogeny, and will form the basis of a range of future research in the still-disputed classifications within this taxon.Fil: Kenny, Nathan J.. Natural History Museum; Reino UnidoFil: Noreña, Carolina. Consejo Superior de Investigaciones Científicas. Museo Nacional de Ciencias Naturales; EspañaFil: Damborenea, Maria Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Zoología Invertebrados; ArgentinaFil: Grande, Cristina. Universidad Autónoma de Madrid; Españ
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Systematic revision of the family Pleioplanidae Faubel, 1983 (Polycladida, Acotylea): New genus and combinations
'Museum National D''Histoire Naturelle', 2018Co-Authors: Rodríguez Jorge, Grande Cristina, Pérez Jacinto, Almon Bruno, Bulnes, Natalia Veronica, Noreña CarolinaAbstract:New morphological information, reconsiderations and the first combination of a generic name based on a previously established species are presented in the current revision of the family Pleioplanidae (Polycladida, Acotylea). Species belonging to this family are briefly presented and Laqueusplana bocki gen. et sp. nov. is described. An identification key to all valid species of Pleioplanidae is provided. Furthermore, results from phylogenetic analyses of the species treated herein are discussed.Museo Nacional de Ciencias Naturales (CSIC); funded by project CGL2011-29916 (Ministerio de Ciencia e Innovación) of the Spanish MICINNPeer Reviewe
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Systematic revision of the family Pleioplanidae Faubel, 1983 (Polycladida, Acotylea): new genus and combinations
'Museum National D''Histoire Naturelle', 2017Co-Authors: Rodríguez Jorge, Grande Cristina, Pérez Jacinto, Almon Bruno, Bulnes, Natalia Veronica, Noreña CarolinaAbstract:New morphological information, reconsiderations and the first combination of a generic name based on a previously established species are presented in the current revision of the family Pleioplanidae (Polycladida, Acotylea). Species belonging to this family are briefly presented and Laqueusplana bocki gen. et sp. nov. is described. An identification key to all valid species of Pleioplanidae is provided. Furthermore, results from phylogenetic analyses of the species treated herein are discussed.This work was supported by the Museo Nacional de Ciencias Naturales (CSIC), funded by project CGL2011-29916 (Ministerio de Ciencia e Innovación) of the Spanish MICINN.Peer reviewe
Carolina Noreña - One of the best experts on this subject based on the ideXlab platform.
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Probing recalcitrant problems in polyclad evolution and systematics with novel mitochondrial genome resources
Genomics, 2018Co-Authors: Nathan J. Kenny, Cristina Damborenea, Carolina Noreña, Cristina GrandeAbstract:Abstract For their apparent morphological simplicity, the Platyhelminthes or “flatworms” are a diverse clade found in a broad range of habitats. Their body plans have however made them difficult to robustly classify. Molecular evidence is only beginning to uncover the true evolutionary history of this clade. Here we present nine novel mitochondrial genomes from the still undersampled orders Polycladida and Rhabdocoela, assembled from short Illumina reads. In particular we present for the first time in the literature the mitochondrial sequence of a Rhabdocoel, Bothromesostoma personatum (Typhloplanidae, Mesostominae). The novel mitochondrial genomes examined generally contained the 36 genes expected in the Platyhelminthes, with all possessing 12 of the 13 protein-coding genes normally found in metazoan mitochondrial genomes (ATP8 being absent from all Platyhelminth mtDNA sequenced to date), along with two ribosomal RNA genes. The majority presented possess 22 transfer RNA genes, and a single tRNA gene was absent from two of the nine assembled genomes. By comparison of mitochondrial gene order and phylogenetic analysis of the protein coding and ribosomal RNA genes contained within these sequences with those of previously sequenced species we are able to gain a firm molecular phylogeny for the inter-relationships within this clade. Our phylogenetic reconstructions, using both nucleotide and amino acid sequences under several models and both Bayesian and Maximum Likelihood methods, strongly support the monophyly of Polycladida, and the monophyly of Acotylea and Cotylea within that clade. They also allow us to speculate on the early emergence of Macrostomida, the monophyly of a “Turbellarian-like” clade, the placement of Rhabditophora, and that of Platyhelminthes relative to the Lophotrochozoa (=Spiralia). The data presented here therefore represent a significant advance in our understanding of platyhelminth phylogeny, and will form the basis of a range of future research in the still-disputed classifications within this taxon.
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The Polycladida (Platyhelminthes) of the Canary Islands. New genus, species and records
Zootaxa, 2017Co-Authors: Daniel Cuadrado, Leopoldo Moro, Carolina NoreñaAbstract:The main focus of this study is the biodiversity of the order Polycladida in the Canary Islands, archipelago belonging to Macaronesia and to the Mediterranean basin hot spot region. Polycladida is a cosmopolitan order with some species distributed worldwide; but it also is comprised of endemic species. Here, 19 polyclad species are revised and determined, ten of which were previously recorded for the Canary Islands (De Vera et al. 2009). A new genus and species Multisepta fengari n. gen., n. sp., of the suborder Acotylea and five new species belonging to the suborder Cotylea including Anonymus ruber n. sp., Enchiridium magec n. sp., Eurylepta guayota n. sp., Acanthozoon aranfaibo n. sp. and Pseudoceros mororum n. sp., are presented and described. In addition, two well-known species, Pseudobiceros wirtzi (Madeira and Cape Verde) and Pericelis cata (Caribbean coasts), are new records for the Canary Islands and for the hot spot region of the Mediterranean basin. Using all available information, including from the morphological study presented here, a key for the species for the Canary Islands has been generated.
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Systematic revision of the family Pleioplanidae Faubel, 1983 (Polycladida, Acotylea): New genus and combinations
European Journal of Taxonomy, 2017Co-Authors: Jorge P. Rodríguez, Cristina Grande, Jacinto Perez, Bruno Almon, Natalia Veronica Bulnes, Carolina NoreñaAbstract:New morphological information, reconsiderations and the first combination of a generic name based on a previously established species are presented in the current revision of the family Pleioplanidae (Polycladida, Acotylea). Species belonging to this family are briefly presented and Laqueusplana bocki gen. et sp. nov. is described. An identification key to all valid species of Pleioplanidae is provided. Furthermore, results from phylogenetic analyses of the species treated herein are discussed.
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for the Atlantic coast of the
2016Co-Authors: Carolina Noreña, Daniel Marquina, Jacinto Perez, Bruno AlmonAbstract:First records of Cotylea (Polycladida, Platyhelminthes) for the Atlantic coast... 1 First records of Cotylea (Polycladida, Platyhelminthes
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Characterization of the complete mitochondrial genomes from Polycladida (Platyhelminthes) using next-generation sequencing.
Gene, 2016Co-Authors: M. Teresa Aguado, Cristina Grande, Michael Gerth, Christoph Bleidorn, Carolina NoreñaAbstract:The complete mitochondrial genomes of three polycladids, the acotylean Hoploplana elisabelloi and the cotyleans Enchiridium sp. and Prosthiostomum siphunculus have been assembled with high coverage from Illumina sequencing data. The mt genomes contain 36 genes including 12 of the 13 protein-coding genes characteristic for metazoan mitochondrial genomes, two ribosomal RNA genes, and 22 transfer RNA genes. Gene annotation, gene order, genetic code, start and stop codons and codon bias have been identified. In comparison with the well investigated parasitic Neodermata, our analysis reveals a great diversity of gene orders within Polycladida and Platyhelminthes in general. By analyzing representative genomes of the main groups of Platyhelminthes we explored the phylogenetic relationships of this group. The phylogenetic analyses strongly supported the monophyly of Polycladida, and based on a small taxon sampling suggest the monophyly of Acotylea and Cotylea.
Juliana Bahia - One of the best experts on this subject based on the ideXlab platform.
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Polycladida phylogeny and evolution: integrating evidence from 28S rDNA and morphology
Organisms Diversity & Evolution, 2017Co-Authors: Juliana Bahia, Vinicius Padula, Michael SchrödlAbstract:Polyclad flatworms have a troubled classification history, with two contradicting systems in use. They both rely on a ventral adhesive structure to define the suborders Acotylea and Cotylea, but superfamilies were defined according to eyespot arrangement (Prudhoe’s system) or prostatic vesicle characters (Faubel’s system). Molecular data available cover a very limited part of the known polyclad family diversity and have not allowed testing morphology-based classification systems on Polycladida yet. We thus sampled a suitable marker, partial 28S ribosomal DNA (rDNA), from Polycladida (19 families and 32 genera), generating 136 new sequences and the first comprehensive genetic dataset on polyclads. Our maximum likelihood (ML) analyses recovered Polycladida, but the traditional suborders were not monophyletic, as the supposedly acotyleans Cestoplana and Theama were nested within Cotylea; we suggest that these genera should be included in Cotylea. The partial 28S rDNA trees were generally well supported and robust but in conflict with both Faubel’s and Prudhoe’s superfamilies. Therefore, we compiled morphological and anatomical characters for all taxa used and examined their distribution on our molecular tree. Combining morphological and molecular evidence, we redefined polyclad superfamilies. Acotylea contain tentaculated and atentaculated groups and is now divided in three superfamilies. The suborder Cotylea can be divided in five superfamilies. In general, there is a trait of anteriorization of sensory structures, from the plesiomorphic acotylean body plan to the cotylean gross morphology. Traditionally used characters, such as prostatic vesicle, eyespot distribution, and type of pharynx, are all homoplastic and likely have misled polyclad systematics so far.
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First records of polyclads (Platyhelminthes, Polycladida) associated with Nodipecten nodosus (Linnaeus 1758) aquaculture
Marine Biodiversity, 2016Co-Authors: Juliana BahiaAbstract:Free-living marine Platyhelminthes of the order Polycladida are known to interact with molluscs, especially bivalves. The impact and damage of polyclads that feed on farmed oysters can be so significant that they are known as oyster leeches. The present contribution identifies three species of polyclads associated with scallop aquaculture at Ilha Grande, southeastern Brazil: one cotylean, Lurymare matarazzoi , and two acotyleans, Imogine tica and Imogine refertus . This is the first time these species are illustrated with photographs of live specimens and histological sections after their original description. This is also the first record of an association of polyclads with a pectinid mollusc. The ecological role of polyclads is still little known, and experiments are lacking. However, it shows that native flatworm species are interacting with Nodipecten nodosus in experimental aquaculture, feeding either on the molluscs or on the associated fauna.
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First records of the order Polycladida (Platyhelminthes, Rhabditophora) from reef ecosystems of Alagoas State, north-eastern Brazil, with the description of Thysanozoon alagoensis sp. nov.
Journal of the Marine Biological Association of the United Kingdom, 2015Co-Authors: Juliana Bahia, Vinicius Padula, Monica Dorigo Correia, Hilda Helena SovierzoskiAbstract:The 230 km long coast of Alagoas State, in north-eastern Brazil, has diverse reef ecosystems, made from corals and of sandstone, that harbour a wide range of marine invertebrate fauna. Little is known about turbellarians of the order Polycladida in most parts of the Brazilian coast, with no record from Alagoas up to date. To fill this gap expeditions were conducted on the reefs from the central coast of Alagoas, where 11 Polycladida species were found: Pericelis cata, Enchiridium evelinae, Pseudoceros bicolor and a possible new colour variation of this species, Pseudoceros rawlinsonae, Pseudobiceros pardalis, Thysanozoon brocchii, Thysanozoon alagoensis sp. nov., Armatoplana leptalea, Adenoplana evelinae, Latocestus brasiliensis, Phaenocelis medvedica. The species are described in detail through photos of live specimens and histological sections. The present work adds six species to the north-eastern Brazilian coast, one of them a new species, and all 11 species are for the first time reported from Alagoas State. Also, it is the first time that Phaenocelis medvedica, Adenoplana evelinae, Latocestus brasiliensis and Armatoplana leptalea are illustrated by full colour photos of live specimens and histological sections.
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Taxonomy of Cotylea (Platyhelminthes: Polycladida) from Cabo Frio, southeastern Brazil, with the description of a new species.
Zootaxa, 2014Co-Authors: Juliana Bahia, Vinicius Padula, Helena Passeri Lavrado, Sigmer QuirogaAbstract:Polyclads are free-living Platyhelminthes with a simple, dorsoventrally flattened body and a much ramified intestine. In Brazil, 66 species are reported; only three from Rio de Janeiro State (RJ). The main objective of this study is to describe and illustrate coloration pattern, external morphology, reproductive system morphology and, when possible, biological and ecological aspects of species of the suborder Cotylea found in Cabo Frio, RJ. Of the 13 cotylean polyclad species found, Pseudobiceros pardalis, Cycloporus variegatus and Eurylepta aurantiaca are new records from the Brazilian coast and one species is new to science, Pseudoceros juani sp. nov. Feeding observations were made of four species. It is the first time that Lurymare utarum, Cycloporus gabriellae, C. variegatus and E. aurantiaca are illustrated with digital photographs of live specimens and histological preparations. This study increases to 70 the number of Brazilian Polycladida and to 14 the number of species known from Rio de Janeiro State. However, the knowledge about Polycladida in Brazil still has gaps, with great parts of the coast remaining unsampled.
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five new records and morphological data of polyclad species platyhelminthes turbellaria from rio grande do norte northeastern brazil
Zootaxa, 2012Co-Authors: Juliana Bahia, Vinicius Padula, Marlon DelgadoAbstract:In Brazil, 66 flatworm species of the order Polycladida are known, most of which collected from the southeastern Braziliancoast. The present study includes morphological descriptions of five species from Rio Grande do Norte State, BrazilianNortheastern coast: Enchiridium evelinae, Phrikoceros mopsus, Pseudobiceros evelinae, Thysanozoon brocchii and Hop- loplana divae. These findings represent the first record of Polycladida for this region of Brazil. Also, for the first time Enchiridium evelinae, Pseudobiceros evelinae and Hoploplana divae are illustrated with color photographs of live spec-imens and histological details. Association with compound ascidians and encrusting bryozoan were observed and com-mented. Our data suggest that knowledge about Brazilian polyclads is underestimated and emphasizes the necessity of further studies to better understand the Polycladida biodiversity in Brazil.
Bernhard Egger - One of the best experts on this subject based on the ideXlab platform.
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Regeneration of the flatworm Prosthiostomum siphunculus (Polycladida, Platyhelminthes)
Cell and Tissue Research, 2020Co-Authors: Tamara Schadt, Veronika Prantl, Alexandra L Grosbusch, Philip Bertemes, Bernhard EggerAbstract:Fueled by the discovery of head regeneration in triclads (planarians) two and a half centuries ago, flatworms have been the focus of regeneration research. But not all flatworms can regenerate equally well and to obtain a better picture of the characteristics and evolution of regeneration in flatworms other than planarians, the regeneration capacity and stem cell dynamics during regeneration in the flatworm order Polycladida are studied. Here, we show that as long as the brain remained at least partially intact, the polyclad Prosthiostomum siphunculus was able to regenerate submarginal eyes, cerebral eyes, pharynx, intestine and sucker. In the complete absence of the brain only wound closure was observed but no regeneration of missing organs. Amputated parts of the brain could not be regenerated. The overall regeneration capacity of P. siphunculus is a good fit for category III after a recently established system, in which most polyclads are currently classified. Intact animals showed proliferating cells in front of the brain which is an exception compared with most of the other free-living flatworms that have been observed so far. Proliferating cells could be found within the regeneration blastema, similar to all other flatworm taxa except triclads. No proliferation was observed in epidermis and pharynx. In pulse-chase experiments, the chased cells were found in all regenerated tissues and thereby shown to differentiate and migrate to replace the structures lost upon amputation.
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A Transcriptomic-Phylogenomic Analysis of the Evolutionary Relationships of Flatworms
Current biology : CB, 2015Co-Authors: Bernhard Egger, François Lapraz, Bartłomiej Tomiczek, Steven Müller, Christophe Dessimoz, Johannes Girstmair, Nives Škunca, Kate A. Rawlinson, Christopher B. Cameron, Elena BeliAbstract:The interrelationships of the flatworms (phylum Platyhelminthes) are poorly resolved despite decades of morphological and molecular phylogenetic studies [1, 2]. The earliest-branching clades (Catenulida, Macrostomorpha, and Polycladida) share spiral cleavage and entolecithal eggs with other lophotrochozoans. Lecithoepitheliata have primitive spiral cleavage but derived ectolecithal eggs. Other orders (Rhabdocoela, Proseriata, Tricladida and relatives, and Bothrioplanida) all have derived ectolecithal eggs but have uncertain affinities to one another. The orders of parasitic Neodermata emerge from an uncertain position from within these ectolecithal classes. To tackle these problems, we have sequenced transcriptomes from 18 flatworms and 5 other metazoan groups. The addition of published data produces an alignment of >107,000 amino acids with less than 28% missing data from 27 flatworm taxa in 11 orders covering all major clades. Our phylogenetic analyses show that Platyhelminthes consist of the two clades Catenulida and Rhabditophora. Within Rhabditophora, we show the earliest-emerging branch is Macrostomorpha, not Polycladida. We show Lecithoepitheliata are not members of Neoophora but are sister group of Polycladida, implying independent origins of the ectolecithal eggs found in Lecithoepitheliata and Neoophora. We resolve Rhabdocoela as the most basally branching euneoophoran taxon. Tricladida, Bothrioplanida, and Neodermata constitute a group that appears to have lost both spiral cleavage and centrosomes. We identify Bothrioplanida as the long-sought closest free-living sister group of the parasitic Neodermata. Among parasitic orders, we show that Cestoda are closer to Trematoda than to Monogenea, rejecting the concept of the Cercomeromorpha. Our results have important implications for understanding the evolution of this major phylum.