Dendrogramma, um fóssil vivo da fauna de Ediacara? Mais de 500 milhões de anos de inatividade da seleção natural...

quinta-feira, setembro 11, 2014

Dendrogramma, New Genus, with Two New Non-Bilaterian Species from the Marine Bathyal of Southeastern Australia (Animalia, Metazoa incertae sedis) – with Similarities to Some Medusoids from the Precambrian Ediacara

Jean Just mail, Reinhardt Møbjerg Kristensen, Jørgen Olesen

Published: September 03, 2014DOI: 10.1371/journal.pone.0102976



Abstract

A new genus, Dendrogramma, with two new species of multicellular, non-bilaterian, mesogleal animals with some bilateral aspects, D. enigmatica and D. discoides, are described from the south-east Australian bathyal (400 and 1000 metres depth). A new family, Dendrogrammatidae, is established for Dendrogramma. These mushroom-shaped organisms cannot be referred to either of the two phyla Ctenophora or Cnidaria at present, because they lack any specialised characters of these taxa. Resolving the phylogenetic position of Dendrogramma depends much on how the basal metazoan lineages (Ctenophora, Porifera, Placozoa, Cnidaria, and Bilateria) are related to each other, a question still under debate. At least Dendrogramma must have branched off before Bilateria and is possibly related to Ctenophora and/or Cnidaria. Dendrogramma, therefore, is referred to Metazoa incertae sedis. The specimens were fixed in neutral formaldehyde and stored in 80% ethanol and are not suitable for molecular analysis. We recommend, therefore, that attempts be made to secure new material for further study. Finally similarities between Dendrogramma and a group of Ediacaran (Vendian) medusoids are discussed.




Citation: Just J, Kristensen RM, Olesen J (2014) Dendrogramma, New Genus, with Two New Non-Bilaterian Species from the Marine Bathyal of Southeastern Australia (Animalia, Metazoa incertae sedis) – with Similarities to Some Medusoids from the Precambrian Ediacara. PLoS ONE 9(9): e102976. doi:10.1371/journal.pone.0102976

Editor: Andreas Hejnol, Sars International Centre for Marine Molecular Biology, Norway

Received: April 3, 2014; Accepted: June 22, 2014; Published: September 3, 2014

Copyright: © 2014 Just et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Data Availability: The authors confirm that all data underlying the findings are fully available without restriction. Most relevant data are within the paper and its Supporting Information files. The studied specimens are stored at Museum Victoria (NMV numbers), Melbourne, Australia and Natural History Museum (ZMUC numbers) of Denmark, Copenhagen, Denmark.

Funding: This work was supported by an Australian Marine Science and Technology/Australian Research Council grant. The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing interests: The authors have declared that no competing interests exist.

FREE PDF GRATIS: PLoS One.