DOI: 10.5061/dryad.18931zcx3
title: Relict from the Jurassic: New family of brittle-stars from a New Caledonian seamount

description: The deep-seafloor in the tropical Indo-Pacific harbours a rich and diverse
 benthic fauna with numerous palaeo-endemics. Here we describe a new
 species, genus and family of brittle-star (Ophiuroidea) from a single
 eight-armed specimen collected from a depth between 360 and 560 m on Banc
 Durand, a seamount east of New Caledonia. Leveraging a robust,
 fossil-calibrated (273 kbp DNA) phylogeny for the Ophiuroidea, we estimate
 the new lineage diverged from other ophiacanthid families in the Late
 Triassic or Jurassic (median=187-178 my, 95% CI = 215-143 my), a period of
 elevated diversification for this group. We further report very similar
 microfossil remains from Early Jurassic (180 my) sediments of Normandy,
 France. The discovery of a new ancient lineage in the relatively
 well-known Ophiuroidea indicates the importance of ongoing taxonomic
 research in the deep-sea, an environment increasingly threatened by human
 activities.
description: Micro-CT scanning. Performed at the Melbourne TrACEES (Trace
 Analysis for Chemical, Earth and Environmental Sciences) Platform by Dr.
 Jay Black (University of Melbourne) using a Phoenix Nanotom m operated
 using xs control and Phoenix datos|x acquisition software (Waygate
 Technologies). The specimen was mounted by wrapping in ethanol soak gauze,
 secured by bubble wrap, and placed within a plastic specimen jar. An x-ray
 energy of 50kV and 300 mA was used for two separate scans, one at a
 coarser voxel resolution of 25 micrometre to capture the full body of the
 specimen and a higher resolution scan at 10 micrometre focusing on a
 region of interest encompassing the main body. Scans were run for 10
 minutes in a fast scan mode collecting 1200 projections through a 360
 degree rotation of the specimen. Volume reconstruction of the micro-CT
 data was performed using Phoenix datos|x reconstruction software (Waygate
 Technologies) applying an inline median filter and ROI filter during
 reconstruction. The data was exported as 16-bit volume files for imaging
 and analysis in Avizo (Thermo Fisher Scientific).
 Phylogenetic analyses. Bayesian dating estimates were obtained
 using BEAST2 v2.4.7 using  a codon position GTR+G+F sequence evolution
 model, with lognormal relaxed-clock model and Yule tree prior (both using
 1/X parameterization). Fossil calibrations are outlined in electronic
 supplementary material Table S3. Maximum likelihood estimates were were
 generated in RAxML v8.1.20 using  a codon position GTR+G+F sequence
 evolution model by running 200 non-parametric bootstraps (the –f i
 command) that retain branch lengths per bootstrap. A species tree was
 estimated using ASTRAL-II, with local posterior support values [19], from
 353 (the most data rich, electronic supplementary material, table S2)
 separate gene trees, drawn from the full 265kb 195 taxa dataset. We used
 genes (rather than exons) as independent loci [20]. Unrooted gene trees
 were generated by RAxML (-f d command) using a single partition GTR+G+F
 model (due to reduced information per gene as compared to the full
 concatenated data). These gene datasets comprised (median) 189 taxa and
 513 sites, with each of the 195 taxa having (median) 343 gene trees (330
 for specimen IE.2007.6821). The ASTRAL species tree figure is presented as
 rooted for ease of comparison.
description: This dataset includes a) MV_Ophiojura_IE-2007-6821_S01.zip
 contains a tiff stack of CT-scan images taken vertically through the
 holotype of Ophiojura exbodi b) MV_Ophiojura_IE-2007-6821_S01_yz.zip
 contains a tiff stack of CT-scan images taken horizontally through the
 holotype of Ophiojura exbodi) c) Ophiojura rendered CT images.zip
 contains various rendered CT-scan images of Ophiojura exbodi showing
 ventral and dorsal sides of the animal, in black and white and false
 colour, and an animation of the animal rotating around a horizontal
 axis. d)
 Ophiojura_79taxa.xml is the BEAST XML input file that was used to create
 the BEAST phylogenic tree in the paper.  e) Ophiojura_79taxa_BEAST MCCtree.tre is
 the phylogenetic tree that resulted from the BEAST analysis (published as
 electronic supplement Figure S2b) f) Ophiojura_195taxa.phy is the input
 file for the RAxML phylogenetic analysis. g)
 Ophiojura_195taxa_RAxML_bipartitions.nwk contains the trees resulting from
 the RAxML analysis (published as electronic supplement Figure
 S1a)  h)
 Ophiojura_195taxa_353genetrees.phy is the input file for the ASTRAL-II
 analysis i)
 Ophiojura_195taxa_353gene_ASTRAL_speciestree.tre contains the ASTRAL trees
 (published as electronic supplement Figure S1b)