Cheilea atlantica Rolán,Leal& Fernández,2014

Cheilea atlantica Rolán,Leal& Fernández,2014 View in CoL ( Fig.9 View Figure 9 E-I)

Cheilea americana Rolán, Redfern & Fernández, 2014 ( Fig. 9 View Figure 9 A-D)

Remarks: Simone (2002: 90-96, figs. 42, 43, 87-89, 348-369) described anatomically what in that time was identified Cheilea equestris in Brazilian coast. The species had as type locality "O[ceano] Indico" ( Linné, 1758: 780), but has been considered of worldwide occurrence,including both coasts of Atlantic Ocean. In Simone (2002: 95) the possibility of the thus far concept of C. equestris should be a complex of species with more restricted distribution was suggested. However, the paper adopted a more conservative approach due to (1) a lack of material from other regions for comparative studies and (2) a list of 8 synonyms, the types, and other data of which need to be surveyed for possible revalidations. Considering these factors, albeit partially, challenges could be raised against the notion of a globally distributed C. equestris .

Despite these precautionary steps, Rolán & Fernandez (2014) did not consider them, neither various studies on the genus and species (including Simone, 2002), along with all known synonyms (MolluscaBase, 2023). This oversight created an opportune scenario for describing three new species in the Atlantic and designating a lectotype for C. equestris from a specimen held by the Linnean Society of London, UK.

The issue is that there are synonyms of C. equestris with a potential for revalidation, and they have a type locality in the Atlantic.The ideal way should be to survey data and specimens (type and types) of all of them.There is the possibility that those newly described species be synonyms of some revalidated synonym.

These are the C. equestris synonyms with (or potentially with) Atlantic type locality.

1) Calyptraea aculeata Reeve, 1858 : pl. 8, fig. 31a-b, Honduras.

2) Calyptraea chlorina Gould, 1846 : pg. 161, Port Praya, Cape de Verds.

3) Mitrularia neptuni Schumacher, 1817: 183 – locality not stated (based on Martini,1769,pl.13,fig.119-120).

4) Patella neptuni Dillwyn, 1817: 1016 , St. Domingo and Falkland Islands.

5) Calyptraea planulata C.B. Adams, 1852: 447 , I. of Muerte, Panama.

6) Calyptraea stella Reeve,1858 :pl. 6, fig. 24, Belize, Honduras.

7) Calyptra tubifera Gray, 1868: 748 , Honduras.

8) Calyptraea umbo Reeve, 1858 : pl. 8, species 33, Honduras.

None of the species listed above share the same type locality as the Atlantic species mentioned in Rolán & Fernandez (2014), namely C. striata Usticke, 1959 (St. Croix), C.americana ( Bahamas) ( Fig.9 View Figure 9 A-D),and C.atlantica (Montague seamount, Brazil) ( Fig. 9 View Figure 9 E-I). Except for C. africana Rolán & Fernández, 2014 : Sal Is., Cape Verde, which has a close locality as C. chlorina .

While these taxonomic issues remain unresolved, what was previously referred to as C. equestris on the Atlantic coast of South America will now be designated as C. americana and C. atlantica . However, it is crucial to note that these species may potentially be synonyms of some of the previously listed synonyms, contingent on a future taxonomic revision.

Both species ( C. americana and C. atlantica ) are primarily distinguishable by their protoconch. The protoconch of C.americana is paucispiral ( Fig. 9D View Figure 9 ), whereas that of C. atlantica is multispiral ( Fig. 9I View Figure 9 ). Upon examination of the MZSP collection, which contains abundant samples of Cheilea from the NE Brazilian coast and Fernando de Noronha oceanic island, all specimens correspond to C. americana . This conclusion includes the samples that resulted the description by Simone (2002). Conversely, the description (including anatomy) provided by Simone (2002) should be reassigned to what is presently referred to as C.americana . Cheilea atlantica , for now, retains to the material studied in the original paper by Rolán & Fernandez (2014).The examined holotype is metalized ( Fig.9F, H View Figure 9 ), and a digitally cleaned version is presented here ( Fig.9E,G View Figure 9 ).