Mitogenome of a new Ramazzottius species (Tardigrada: Eutardigrada: Ramazzottiidae) discovered in rock pools along with its temperature and desiccation-related proteins repertoire

Abstract Ramazzottius is a widespread genus of tardigrades with extreme cryptobiotic capabilities. Thanks to its ability to survive desiccation and freezing, this genus is usually recorded from harsh habitats such as exposed mosses and lichens and rock pools. In the last years, research focused on both describing Ramazzottius diversity and revealing the molecular mechanisms behind their cryptobiotic capabilities. Despite the research efforts in these fields, much still remains to be discovered. Here we describe a new Ramazzottius species from an Italian rock pool by means of integrative taxonomy (morphology, morphometry, and DNA sequencing) and sequenced its genome with Nanopore technology to provide an assembled mitogenome and annotate its Temperature and Desiccation Resistance Proteins (TDPR) repertoire. The new gonochoric species is phylogenetically close to the parthenogenetic R. varieornatus , a strain of which (YOKOZUNA-1) has been adopted as model organism for the study of cryptobiosis. The mitogenome of the new species shows perfect synteny with R. varieornatus and shares with it most of the TDPR genes. The relative genetic similarity of the new species to the model R. varieornatus , combined with unique biological traits (for example the difference in reproductive mode and the unique habitat it colonizes), makes the new species a potential new addition to the range of model tardigrade species.