9 to + 1.0 °C) ( Clark et see more al., 2007). This slow rate of regeneration means that if a large length of arm was lost it could take approximately 3 years to fully re-grow. In addition to its slow regeneration rate O. victoriae has an unusual and, as yet, unexplained delay in the onset of regeneration ( Clark et al., 2007). This delay in the onset of regeneration of ~ 5 months is very unusual, but a similar lag phase has also been demonstrated for another Antarctic brittle star ( Clark and Souster, in press). Hence these Antarctic species present as novel candidates for the investigation of regeneration processes, in

particular, the use of molecular analyses to provide fine-scale detail of the signalling pathways invoked and the factors determining the cold environment lag phase. In terms of publicly available sequence data for O. victoriae, recent studies

into the phylogeography and potential cryptic speciation of O. victoriae have provided DNA sequences for three mitochondrial genes ( Hunter and Halanych, 2010), represented multiple times within the drug discovery 68 DNA sequence entries in NCBI Genbank for this species. With regard to sequences for the Ophiuroidea, there were only 2,805 sequences for Ophiuroidea in NCBI GenBank representing less than 30 different genes (at 23/05/2012), the vast majority, again representing mitochondrial genes. Clearly, such a paucity of DNA sequence information, particularly nuclear sequence,

limits the study of gene expression in this organism and also ophiuroidea in general. In this first study of the transcriptome of O. victoriae we used 454 pyrosequencing to increase the available cDNA sequence information and also identify putative candidate genes for use in future investigations of delayed regeneration in this circum-Antarctic locally dominant scavenger. O. victoriae used in this study were collected by SCUBA pheromone divers from near the British Antarctic Survey research station at Rothera Point, Adelaide Island, West Antarctic Peninsula (67° 34.5´ S, 68° 07.0´ W) in the austral summer of 2005/2006. The material used in this study was collected as described in Clark et al. (2007). Briefly, following collection the animals were kept in flow through aquaria and one arm of each brittle star was amputated approximately 10 segments from the central disc. Regenerating animals were sampled on a monthly basis for 12 months by cutting the regenerating arm before the wound site/regenerating appendage. Additional samples were taken from fifteen animals on a weekly basis for four weeks after amputation. Each sample was placed in RNAlater (Applied Biosystems) and, after an overnight incubation at 4 °C, was placed at − 80 °C until used. RNA was extracted from selected monthly and weekly samples that represented the full range of the regenerative process in O.