Revision of Gibberula Lucia Jousseaume, 1877 and Report of an Allopatric Sibling Form (Gastropoda Cystiscidae)
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Biodiversity Journal, 2021, 12 (1): 235–244 https://doi.org/10.31396/Biodiv.Jour.2021.12.1.235.244 Revision of Gibberula lucia Jousseaume, 1877 and report of an allopatric sibling form (Gastropoda Cystiscidae) Franck Boyer1 & Walter Renda2* 14, impasse Pasquier, 30190 Garrigues Sainte Eulalie, France; e-mail: [email protected] 2 Via Bologna, 18/A, 87032 Amantea (Cosenza), Italy; e-mail: [email protected] *Corresponding author ABSTRACT Gibberula lucia Jousseaume, 1877 (Gastropoda Cystiscidae) is revised, and the best conserved among the three MNHN syntypes is selected as lectotype. The typical form of G. lucia shows an original shell decoration made of continuous wavy axial lines. The distribution of this form seems to be restricted to the northwestern group and to the southern group of the Cape Verde Archipelago. A population showing interrupted axial lines is reported from Boa Vista and it looks as being perfectly similar to populations ranging off the Cap Vert Peninsula (Senegal) and off Fuerteventura (Eastern Canary Archipelago). Due to uncomplete documentation, the precise taxonomic status of this distinctive phena cannot be stated, at present, but despite its fragmented distribution, the concerned populations are united under the provisional term of G. cf. lucia, in the wait of further data. KEY WORDS Anthropic introduction; Cystiscidae; Gibberula; phenetic variability; sibling species. Received 11.11.2020; accepted 18.02.2021; published online 30.03.2021 INTRODUCTION restricted to this area. Boyer considered G. lucia and G. almadiensis as being morphologically closer The Gibberula Swainson, 1840 (Gastropoda to the G. oryza group (revision in Gofas, 1990), Cystiscidae) species detaining shells decorated of whereas G. thomensis was considered as holding no various patterns of axial wavy lines (“zic-zac” pat- close relative off West Africa. Boyer noted finally tern) were characterized by Boyer (2004) as consti- that these three species seem to have a narrow or a tuting a possible polyphyletic complex composed fragmented distribution, in the whole limited to in- of several more or less autonomous species groups, sular or peninsular ranges, what is suggesting a re- most of them proving to have a wide intertropical lictual status within the West African Province. distribution. Three species were reported to range Gibberula thomensis has been formally revised off West Africa: G. lucia Jousseaume, 1877 de- by Gofas & Fernandes (1988) and G. almadiensis scribed from the Cape Verde Archipelago, well- has been described more recently with a rather con- known from the Cap Vert Peninsula (Dakar, sistant information. Despite a first review by Senegal) and recently recorded from Fuerteventura Moreno (2012), the oldest described species G. (Eastern Canary Islands); G. thomensis (Tomlin, lucia remains perfectly elusive in the Cape Verde 1918) known as endemic species from São Tomé & Archipelago (only known by the type lot from Santa Principe; and G. almadiensis Pin & Boyer, 1995 de- Luzia and by one shell from Santiago Island). A re- scribed from the Cap Vert Peninsula and apparently lated population from the Senegal, despite being 236 FRANCK BOYER & WALTER RENDA abundant in shallow water of the Cap Vert Penin- formed in Agadir (F. Swinnen, J.L. Delemarre, G. sula, was never documented accurately, the succinct Hervillard and the first author), in Dakhla (J.L. elements given by Pin & Boyer (1995) playing just Delemarre, G. Hervillard), in Nouadhibou (E. as a rough comparison with the deeply-distinctive Rolán) and in the Bijagos Archipelago (J.L. Dele- G. almadiensis. In the course of the study applied marre). The public collections of IFAN-Dakar and to this question, the authors discovered that a dis- of the Paris Museum were studied on the same criminatory chromatic feature of the shell remained ground. Special investigations were payed about the hidden to previous students, which feature allows possible occurrence of related forms in the Canary to distinguish the nominal G. lucia ranging in the Islands, through the extensive collections saved for Cape Verde Islands from the population of G. cf. the whole Archipelago (J.M. Hernández, F. Swin- lucia ranging off the Cap Vert Peninsula. This dis- nen) or for more focused fields such as Lanzarote tinctive shell decoration feature occurring in the (F. Sicilia Guillen, W. Engl and the first author). population from Senegal is also found in two shells In the whole, numerous lots of empty and live recently collected in Boa Vista as well as in the pop- shells collected specimens were studied from the ulation recorded from Fuerteventura (Engl et al., Cap Vert Peninsula (hard bottoms: 0–4 m by 2009; Hernández et al., 2011). This situation leads snorkeling and 5–40 m by diving; soft bottoms : 3– to reconsider the identity of the two phenae, and to 17 m by dredging), but no further specimens were tackle plausible hypothesis about their taxonomic found from other continental localities out of the and biogeographic status. Dakar area. However, a lot of three fresh adult shells from Fuerteventura perfectly matching the shell features of the Dakar population was exam- MATERIAL AND METHODS ined in the Collection JM Hernández (lot labelled as ex-Manuel Bermejo Pérez, Las Palmas de GC) The populations attributable to the typical form (Fig. 17). According to the late JM. Hernández of G. lucia were studied through the type series pre- (pers. comm.), M. Bermejo collected in Fuerteven- served in the Paris Museum (Figs. 1–3) and through tura several beached empty shells attributable to G. the single shell from Santiago Island collected by cf. lucia, but the sampling circumstances were not A. de Oliveira and reported by Moreno (2012) (Fig. reported (grouped spots or general distribution, 6). Any other record about this typical form was not number of specimens, one-time findings on a single found in the scientific literature as well as in the stay or recurrent samplings along time, etc). grey literature. We did not find any clue about such The live specimens collected off the Cap Vert a form in the consulted European private collections Peninsula were sampled in sandy weeds/moss on devoting more especially to the Cape Verdian mil- rocks or in fine gravels among detritic/mixed envi- limetric marine fauna and dealing with appropriated ronments, from the low tide line in protected places technics of sampling on hard bottoms (brushing on (from N’gor and Les Almadies northwards to Bel- bag by snorkeling or by diving), such as for instance Air and Gorée Island southwards), down to lower the collection of E. Rolán for the whole infralittoral by diving (station Petit Thiouriba, 33 m). Archipelago, or the collections of J. Pelorce and of Only one unfresh shell and few worned shells were the first author for more focused samplings in Sal collected by dredging on soft bottoms in the Bay of Island. Gorée (southern side of Dakar, 5–17 m) and along The related population from the Cap Vert Penin- the Petite Côte (Central Senegal, 3–8 m). Live ani- sula (Senegal) (Figs. 12–16, 18–26), provisionally mals from various stations of the Cap Vert Peninsula named here as G. cf. lucia, was studied mainly were drawn by the first author during his collecting through the samplings performed in the Dakar area stays in Dakar along the period 1995–2000. by J. Pelorce, P. Petit de Voize, JL. Delemarre, G. The photography of the lectotype of G. lucia has Hervillard and the first author, and through a com- been performed by Benoît Fontaine (MNHN). The plete checking of the collection of the late M. Pin colour drawings of specimens of G. cf. lucia were (Dakar). While waiting to verify the real extension performed in the field by the first author. The orig- of the distribution of this “continental form”, a re- inal photos dedicated to this article were performed search was payed along several collections per- by the second author, as well as the Photoshop skills Revision of Gibberula lucia Jousseaume, 1877 and report of an allopatric sibling form (Gastropoda Cystiscidae) 237 allowing to reveal the accurate dorsal decoration of tourné du côté du bord columellaire; à l’extrémité the lectotype of G. lucia and of the shells from Boa antérieure elles sont beaucoup plus finement encore Vista, while increasing the contrast and the density apparentes alors que près de la suture elles sont à in a monochrom picture. peine perceptibles et manquent même dans la plupart ABBREVIATIONS AND ACRONYMS. des individus. La spire, composée de 3 tours ½, CFB: collection F. Boyer, Garrigues Sainte Eulalie forme à l’extrémité postérieure un petit mamelon (France); CJH: collection J.M. Hernández, Galdar lisse et luisant, entouré à la base d’un petit anneau (Spain); CJP: collection of Jacques Pelorce, le brunâtre; les sutures sont obturées par un enduit vit- Grau-du-Roi (France); MNHN: Muséum national reux assez épais; l’ouverture, placée sur le côté droit d’Histoire naturelle, Paris (France); NMR: Natural de la face inférieure, a la forme d’une fente allongée History Museum, Rotterdam (Netherlands); ad: et étroite, s’élargissant un peu en avant où elle se ter- adult; juv: juvenile; L: shell length; sh: empty shell; mine en une large gouttière sur les bords de laquelle spm: live collected animal; stn: station. on aperçoit de chaque côté deux petites tâches d’un blanc jaunâtre. Son bord externe, épais au milieu et aminci, aux extrémités, est crénelé intérieurement de RESULTS dents si petites, que la loupe est nécessaire pour les distinguer; Le bord columellaire, arqué et calleux, Systematics est divisé en avant par deux plis obliques, épais et saillants, et en arrière de denticules d’autant plus Familia CYSTISCIDAE Stimpson, 1865 saillantes qu’on se rapproche d’avantage des plis antérieurs”. Subfamilia PERSICULINAE Coovert et Coovert, 1995 COMPLEMENTARY DESCRIPTION.