Hepatogaster Cejka, 1910

Rota, Emilia, Martinsson, Svante & Erséus, Christer, 2018, Two new bioluminescent Henlea from Siberia and lack of molecular support for Hepatogaster (Annelida, Clitellata, Enchytraeidae), Organisms Diversity & Evolution (New York, N. Y.) 18 (3), pp. 291-312 : 309

Status of Hepatogaster Cejka, 1910

We compared the genetic sequences of our two new Siberian species and the unnamed species A, all sharing the Hepatogaster -like condition of gut diverticula, with those of H. magnampullacea recently described from Korea and stated to possess a “multitubular substructure” ( Dózsa-Farkas et al. 2015) and also with sequences of H. ochracea provided by the same authors, and we found no close affinity. Admittedly, the position of H. magnampullacea is not clear, as the authors likened the substructure of its diverticula to that “characterizing” H. ventriculosa , H. jutlandica , and H. groenlandica . In any case, by considering also the other Henlea species includ- ed in our analysis, the molecular phylogeny seems to support a transition from smoother diverticula walls via more folded to the tubuliferous condition of Hepatogaster as previously suggested, instead of a sister-group relationship between Hepatogaster and other Henlea species. Actually, Hepatogaster would seem to be an artificial grouping of taxa showing similar modifications by convergence (polyphyletic grade). The question whether the tubuliferous condition is a plesiomorphy (as suggested by Tynen et al. 1991, based on “very preliminary outgroup comparisons”) or a derived condition with respect to smoother diverticula needs more data to be resolved with full support. According to our estimated phylogeny the tubuliferous condition is apomorphic, and has evolved more than once, but our phylogeny is just a start: as we tried to maximize the number of species included, we have limited gene coverage of some. This probably explains the low support in our tree. The low gene coverage may also be the explanation for not recovering Henlea as monophyletic. Further, for our phylogeny we only sampled 13 of the over 30 accepted species of Henlea (Schmelz and Collado 2012) .