Retilaskeya, Marshall, 1978

Romani, Luigi, Rolán, Emilio, Mifsud, Constantine & Crocetta, Fabio, 2017, Redescription of Retilaskeya horrida (di Monterosato, 1874) comb. nov. and a re-evaluation of the taxonomic affinity of the genus Retilaskeya (Caenogastropoda: Triphoroidea), Journal of Natural History 52 (1 - 2), pp. 115-135 : 129

Retilaskeya familial and subfamilial replacement

Retilaskeya Marshall, 1978 was originally erected as belonging to the Eumetulinae Golikov and Starobogatov, 1975, a subfamily of Cerithiopsidae H. Adams and A. Adams, 1853 at that time. In particular, Marshall (1978) compared Retilaskeya with Laskeya Iredale, 1918 sensu stricto, currently considered a synonym of Eumetula Thiele, 1912 (nom. nov. for Eumeta MØrch, 1868 non Walker, 1855, type species Cerithium arcticum MØrch, 1857 ) ( García 2009).

Eumetulids have a troubled taxonomic history. Originally introduced by Golikov and Starobogatov (1975) as a family of the Cerithiopsacea H. Adams and A. Adams, 1853 along with Cerithiellidae Golikov and Starobogatov, 1975 (an invalid replacement name for Newtoniellidae Korobkov, 1955 ), they were made a subfamily of Cerithiopsidae by Marshall (1978). Subsequently, Gründel (1980) and Nützel (1998) considered Eumetulidae Golikov and Starobogatov, 1975 as a valid family. Finally, Bouchet and Rocroi (2005) placed it as a subfamily of Newtoniellidae , a taxonomic assignment where it remained until present ( Bouchet 2011a). Strangely, the last taxonomic movement involved most genera previously ascribed by Bouchet and Rocroi (2005) to Eumetulinae, that were soon moved to Newtoniellidae ( Bouchet 2011b) , while some others (e.g. Cerithiopsilla Thiele, 1912 , Cerithiopsidella Bartsch, 1911 , Specula Finlay, 1926 , and Socienna Finlay, 1926 ), including Retilaskeya , remained within Cerithiopsidae ( Bouchet 2011c) , although it is unknown if this happened intentionally or simply due to an oversight. However, as mentioned above, Retilaskeya clearly belongs to the Eumetula -group (Nützel 1998), an opinion shared by Bouchet and Warén (1993), who suspected that Marshallaskeya Gründel, 1980 (currently considered a synonym of Retilaskeya : see Marshall and Bouchet 2015b) and Eumetula may even be synonyms. The main distinction between Newtoniellidae and Cerithiopsidae is still largely based on Nützel (1998), who reported diagnostic data of the former family mostly under Eumetulidae . These are diagnosed on protoconch ( Newtoniellidae : multispiral types with a sculpture of collabral axial ribs and non-multispiral types with axial sculpture vs. Cerithiopsidae : multispiral types with smooth sculpture or generally without collabral axial ribs) and radular ( Newtoniellidae : basic radula with wide teeth and tips vs. Cerithiopsidae : modified radula with extremely elongated teeth) features. In the light of the data presented here and the observations reported in the original Retilaskeya description ( Marshall 1978), we suggest to move Retilaskeya taxa from the family Cerithiopsidae to the family Newtoniellidae . A similar situation was also recently highlighted by Fernandes and Pimenta (2017), who commented on several genera currently placed in Cerithiopsidae that presumably would better fit Newtoniellidae , reinforcing the need for a molecular phylogeny to disentangle them. Relevant to our suggestions, we noticed a strange loop within the WoRMS database: Marshallaskeya [originally described as a subgenus of Retilaskeya (see Gründel 1980), as also currently listed in Marshall and Bouchet (2015a)] was ‘virtually’ moved within Newtoniellidae ( Marshall and Bouchet 2015a) , but this does not hold true for Retilaskeya ( Marshall and Bouchet 2015b) . However, according to our bibliographic research, this action was not based on any sort of publication, and it is first formally stated here. The most recent treatment of these taxa are Nützel (1998), where Retilaskeya was omitted in the introduction and Marshallaskeya was raised as a valid genus within Eumetulidae (although both genera were then discussed within the Eumetula -group), and Bouchet and Rocroi (2005), who moved the Eumetula -group within Newtoniellidae but did not analyse single genera one by one (see also discussions above).