Danilia Brusina, 1865

Herbert, D. G., 2012, A revision of the Chilodontidae (Gastropoda: Vetigastropoda: Seguenzioidea) of southern Africa and the south-western Indian Ocean, African Invertebrates 53 (2), pp. 381-381 : 410-412

Genus Danilia Brusina, 1865

Olivia: Cantraine 1835: 387 [non Olivia Bertolini, 1810 (?Porifera)]. Type species: Olivia otaviana Cantraine, 1835 , by monotypy.

Craspedotus: Philippi 1847:23 [non Craspedotus Schoenherr, 1844 (Coleoptera) ]. Type species: Monodonta limbata Philippi, 1844 [= Monodonta tinei Calcara, 1839 ], by monotypy.

Otavia: Gray 1847: 145 (non Risso, 1826), laps. cal. for Olivia Cantraine, 1835 .

? Heliciella : O.G. Costa 1861: 64. Type species: Heliciella costellata O.G . Costa, 1861, by subsequent designation (Dall 1927: 134).

Danilia: Brusina 1865: 25 . Type species: Monodonta limbata Philippi, 1844 [= Monodonta tinei Calcara, 1839 ], by monotypy.

Nomenclatural remarks: Beu and Climo (1974) stated that Brusina (1865) proposed the name Danilia as a replacement name for the homonymous Olivia Cantraine, 1835 . However, I can find no evidence in either Brusina (1865) or Brusina (1866) that this was his intention. In fact, he made no mention of Olivia Cantraine, 1835 . Had he proposed Danilia expressly as a replacement for Olivia , the type species of Danilia would have been that of Olivia (ICZN 1999: Art. 67.8), namely Olivia otaviana Cantraine, 1835 (by monotypy). Instead, the type species of Danilia (by monotypy) is Monodonta limbata Philippi, 1844 [= Monodonta tinei Calcara, 1839 ]. The type species of Olivia , O. otaviana , has traditionally also been considered to be synonymous with Calcara’s Monodonta tinei and is the earlier name, but Palazzi and Villari (2001) consider O. otaviana to represent a distinct fossil species – an opinion shared by Landau et al. (2003). In such case, the type species of Danilia and Cantraine’s Olivia are not the same and they are thus subjective rather than objective synonyms.

Keen (1960) listed Heliciella O.G. Costa, 1861 , in the synonymy of Olivia , but Beu and Climo (1974) considered the affinity of this taxon with Olivia and thus with Danilia to be debateable, since its type species, H. costellata O.G. Costa, 18612, was based on a very juvenile shell. (The specimen of H. costellata figured by O.G. Costa (1861) has a diameter of 1.0 mm and comprises only approx. 1.5 teleoconch whorls.) They chose instead to employ the younger name Danilia on account of this uncertainty. However, Monterosato (1884) had earlier stated that H. costellata was a juvenile shell of Danilia tinei and certainly the figures of juvenile D. tinei provided by Scaperrotta et al. (2009) clearly support the view that H. costellata is a juvenile Danilia . However, Palazzi and Villari (2001), recognising H. costellata as a species of Danilia , believed it to be distinct from D. tinei and to represent a second Recent European species of this genus. Thus Heliciella and Danilia are evidently synonymous and since both are valid names, the earlier one, Heliciella , ought to be afforded priority. However, in order to maintain prevailing usage, and in accordance with ICZN, Art. 23.9 (ICZN 1999), the principle of priority can be moderated, provided the conditions of Art. 23.9.1.1 and Art. 23.9.1.2 are met. In this regard, I am not aware that Heliciella has been used as a valid name after 1899 (Art. 23.9.1.1) and Danilia has been used more than 25 times in the last 50 years by at least 10 different authors (Art. 23.9.1.2) ( Beu & Climo 1974; Powell 1979; Piani 1980; Aimassi et al. 1983; Guidastri et al. 1984; Spadini 1986; Graham 1988; Vaught 1989; Hickman & McLean 1990; Poppe & Goto 1991; Wilson 1993; Giannuzzi-Savelli et al. 1994; Jansen 1996; Millard 1997; Higo et al. 1999; Sasaki 2000; Palazzi & Villari 2001; Vilvens 2001; Spencer et al. 2002; Landau et al. 2003; Rolán 2005; Vilvens &

2 Beu and Climo (1974) cited the type species of Heliciella as H. costellata O.G. Costa, 1861 , by monotypy. In fact, O.G. Costa (1861) described two species within his new genus Heliciella , H. costellata and H. mutabilis . The type species of Heliciella was not fixed until Dall (1927: 134) formally designated it to be H. costellata [although Monterosato (1884: 109) might also be deemed to have done the same]. A subsequent designation of H. mutabilis as the type species of Heliciella by Bouchet and Warén (1988: 86) is invalid.

Héros 2005; Poppe et al. 2006; Crocetta & Spanu 2008; Poppe & Tagaro 2008; Kano 2009; Scaperrotta et al. 2009; Spencer et al. 2009; Bandel 2010; De Simone & Kosuge 2010). Some of these, despite recognising the priority of Heliciella over Danilia , have continued to use the latter as the valid name. Therefore, in accordance with Art. 23.9, Danilia is to be afforded priority over the earlier, but unused Heliciella . Danilia thus becomes a nomen protectum and Heliciella a nomen oblitum.

Remarks: The genus Danilia is known primarily from relatively deep water and has a fossil record extending back to the Lower Cretaceous ( Beu & Climo 1974). Nine Recent species are known from the Indo-West Pacific, eight of which were discussed and illustrated (mostly type specimens) in a useful contribution by Vilvens and Héros (2005). The differences between the species are in some cases small, and Beu and Climo (1974) cautioned that without more detailed comparative study, it is impossible to be certain whether each of these nominal taxa represents a genuinely distinct species, or whether there are fewer, more widespread and sculpturally variable ones – an observation with which I concur. The problem is exacerbated by the fact that most descriptions have been based on very few specimens and thus give no indication of intraspecific variability. These difficulties notwithstanding, I describe below two additional species, since neither appears clearly referable to any of the described taxa.

Danilia species generally live on hard substrata.Whilst most species seem to be scarce, a Mediterranean species, tentatively identified as Danilia costellata (O.G. Costa, 1861) , may be locally abundant in colonies of the gorgonian Corallium rubrum (Linnaeus, 1758) ( Crocetta & Spanu 2008) . Schepman (1908), Beu & Climo (1974) and De Simone & Kosuge (2010) also reported species living in deep-water coral communities. D. textilis (below) was found living primarily in sponge dominated communities, but such communities frequently included deep-water corals. Guidastri et al. (1984) and Smriglio et al. (1989) reported a similar association between Putzeysia wiseri (Calcara, 1842) and deep-water Scleractinia in the Mediterranean.

The radula of Danilia tinei (Calcara, 1839) was illustrated by Guidastri et al. (1984 as D. otaviana ) and that of D. insperata was figured and discussed in detail by Beu and Climo (1974). That of D. textilis described below is very similar.