Short CommunicationThe mitochondrial genome of Colossendeis megalonyx supports a basal position of Colossendeidae within the Pycnogonida

We present the almost complete (16,007 bp) mitochondrial genome of a Colossendeis megalonyx specimen from the Southern Ocean and discuss gene order and tRNA structure in a comparative phylogenetic context. Our data suggest a basal position of the colossendeid lineage corroborating earlier phylogenetic studies but disagreeing with results of a recently published study that supported a highly derived sister-group relationship of Colossendeidae and Nymphonidae. Our results, together with BLAST searches and phylogenetic comparisons, indicate that the specimen presented as Colossendeis sp. in a series of recent studies had been misidentified. It has now been identified as a nymphonid species.

Research highlights► New mitogenome of pycnogonid Colossendeis megalonyx is presented. ► Very basal, typical arthropod groundplan gene order and tRNA structure. ► Conflict to derived genome order found for Colossendeis sp. (Masta et al. 2010). ► Conclusion: Colossendeis sp. (Masta et al. 2010) is misidentified Nymphon species. ► The results of the mitogenome of Colossendeis corroborate actual phylogenies.