Typosyllis antoni, Aguado & Helm & Weidhase & Bleidorn, 2015

Aguado, María Teresa, Helm, Conrad, Weidhase, Michael & Bleidorn, Christoph, 2015, Description of a new syllid species as a model for evolutionary research of reproduction and regeneration in annelids, Organisms Diversity & Evolution (New York, N. Y.) 15 (1), pp. 1-21 : 15-17

T. antoni n. sp. as a model for evolutionary studies in Syllinae

The number of new species within Syllidae is increasing considerably (San Martín and Aguado, accepted), especially during the last decades. Increasing number of detailed descriptions and comprehensive studies about Syllidae ( Aguado et al. 2007, 2012; Aguado and San Martín 2009) enable now the localization and description of new taxa within this group. We provide herein a description of a new species, T. antoni n. sp., which includes information obtained from several different techniques (light microscopy, SEM, cLSM, and molecular phylogenetic analyses). This study may constitute a framework for future descriptions of Syllidae . The phylogenetic analyses performed herein include most of all available data for species of Syllinae (a total of 86 from the GenBank, plus 4 more from Australia included for the first time for this study). We find that T. antoni n. sp. is closely related to T. heronislandensis from Australia (see the “Remarks” section). This sister group relationship supports the generic assignation of the new species proposed herein as Typosyllis . Moreover, our results indicate a pacific origin for the species, which was introduced into our seawater aquarium. A potential source could be so called living stones purchased from an aquarium shop which originate from Indonesia.

Whereas the natural source location for this newly described species remains unclear, the available data makes it immediately to one of the best investigated syllids, emphasizing its potential as model for the whole group. T. antoni n. sp. can be kept in artificial seawater over long times (at least more than 2 years in the Leipzig facility, yet), where it also reproduces sexually. This could be documented through male and female stolons, which can be observed regularly (under the here described conditions, a monthly cycle is assumed). Additionally to sexual reproduction, we were able to demonstrate the regeneration ability of this species. We find that the anterior as well as the posterior end regenerate, even though until now, we find no evidence for the regeneration of

Syllis ypsiloides (after Aguado et al. 2008), Typosyllis antoni n. sp., Syllis gracilis australiensis , and parapodium of S. marugani (after Aguado et al. 2006)

the proventricle. Moreover, available Illumina-based transcriptomic data for T. antoni n. sp. ( Weigert et al. 2014, see accession SRX 513556 in the NCBI short read archive) enables future gene expression studies in this and closely related species, as primer for conserved regions of genes of interest might be designed for many other Syllinae . Besides available molecular data, we provide a detailed description of the musculature by F-actin staining coupled with cLSM. Our experiments show that these animals are well suited for microscopic studies due to their size and transparency. Besides this, standard immunocytochemical protocols work well for T. antoni n. sp. In summary, we suggest that this species is well suited for evolutionary studies connected to reproduction and regeneration. Phylogenetically related species of the Syllis - Typosyllis complex may show similar characteristics and should be also considered for this type of studies.