The endemic West African species of the family Glycymerididae (Mollusca: Bivalvia), with description of two new species 1 2 Frank Nolf and Frank Swinnen 1 Pr. Stefanieplein, 43/8 B-8400 Oostende, Belgium [email protected] 2 Lutlommel, 10B, B-3920 Lommel, Belgium [email protected] Keywords: Glycymeris, GLYCYMERIDIDAE, Banié and Gabon, Glycymeris scripta (von Born, BIVALVIA , MOLLUSCA, new taxon, W Africa. 1778) in the coastal waters of Mauritania, the Canaries, Senegal and Sierra Leone and finally Abstract: Several decades after the discovery of Glycymeris stellata (Bruguière, 1789) in Madeira, specimens of a new species of Glycymeris, more Canary Islands, Mauritania, Senegal, Sierra material turned up from the Canaries and Leone, Principe Island, Cameroon and Angola. Senegal. This species is finally described in the A few other species are typically European and present paper. Specimens of Glycymeris Mediterranean but only occur sporadically in rafaelmesai sp. nov. from the Canaries and Madeira, the Canaries and the coasts of NW Mauritania have already been mentioned and Africa (from Morocco to Western Sahara): figured in recent literature. Further research also Glycymeris nummaria (Linnaeus, 1758) in the revealed its presence in Senegal and Angola. Canaries, Glycymeris pilosa (Linnaeus, 1767) Another new species from Angola is briefly throughout the Mediterranean Sea and the mentioned. The remaining endemic West African Atlantic coasts of Portugal, less frequently in species of the genus Glycymeris are described Madeira, Morocco, Western Sahara and and compared with each other in this paper. Mauritania and finally the recently described species Glycymeris vanhengstumi Goud & Abbreviations: Gulden, 2009, from Madeira, the Canaries and CFD: Private collection of Francisco Déniz Morocco, very similar to Glycymeris glycymeris (Gran Canaria, Canary Islands, Spain). (Linnaeus, 1758) which occurs from Norway to CFN: Private collection of Frank Nolf the E Atlantic coasts of the Iberian Peninsula, the (Oostende, Belgium). western Mediterranean Sea (from Spain to Sicily CFSG: Private collection of Francisco Sicilia in the east), the Azores, Madeira, the Canary Guillén (Lanzarote, Canary Islands, Islands and Mauritania. Spain). In a next paper, treating typical NE Atlantic and CFS: Private collection of Frank Swinnen Mediterranean representatives of the genus (Lommel, Belgium). Glycymeris [Neptunea, 12(3) in preparation)], the CRM: Private collection of Rafael Mesa latter species will be treated together with (Lanzarote, Canary Islands, Spain). Glycymeris bimaculata (Poli, 1795) and LV: left valve. Glycymeris arabica (H. Adams, 1871). RV: right valve. R. Gómez & J.M. Pérez (2011) identified an H.: Height. unknown species of which four specimens were L.: Length. present in the collections of the authors, two PEMARCO: Pêche Maritime du Congo. specimens from Lanzarote collected at a depth RBINS: Royal Belgian Institute for Natural of 40 m and two other shells trawled at -18 m, off Sciences, Brussels, Belgium. Cabo Blanco (Mauritania) as Glycymeris sp. We were so lucky as to obtain two further specimens Introduction: The family GLYCYMERIDIDAE is from Mauritania in the ’70s-’80s of the previous represented by a small number of species in the century (leg. Ramon Gómez). These shells have E Atlantic along the coasts of NW and W Africa. often been confused with Glycymeris glycymeris Four of them are already known: Glycymeris (Linnaeus, 1758), Glycymeris stellata (Bruguière, concentrica (Dunker, 1853) in Mauritania, the 1789) and Glycymeris scripta (von Born, 1778). Canaries, Cape Verde Islands, Senegal-Guinea, A lot of similar specimens have been obtained Ivory Coast, Ghana, Gabon, and Angola, from different localities in the past two years, Glycymeris formosa (Reeve, 1843) in the Cape especially from the Canaries and also from Verde Islands, Principe Island, São Tomé, Ile Mauritania, Senegal and even one specimen Neptunea, 12(2) 1 September 2013 1 from Angola. Belgian fishermen (PEMARCO) The outline is not a good characteristic to brought up many shells from dredging off the distinguish the different species. It partially coasts of Angola between Cabinda and Walvis depends on the kind of substrate in which the Bay (Namibia, SW Africa) from the early animal is buried. In hard substrates specimens nineteen sixties to about 1975. The bycatch of tend to be more convex and oblique as the molluscs during these fishing activities was mantle has been damaged during the burrowing prolific and beside finding Acesta angolensis process. Adam & Knudsen, 1955; Adinopsis skoogi The anterior muscle scar is narrower than the Odhner, 1923; Aporrhais pesgallinae Barnard, posterior one. The lower part is obliquely 1963; Fusinus albinus A. Adams, 1856; Fusinus truncated. The posterior muscular scar is nearly caparti Adam & Knudsen, 1955; Latirus mollis circular but the lower part is narrowing below. Sowerby, 1913; Xenophora testigera digitata von There is no pallial sinus. The interior is Martens, 1878 and many others (MARGINELLIDAE, porcellaneous and the inner ventral margin is TURRIDAE, …), some new species such as strongly crenulated. Europicardium nolfi Swinnen, 2010; Nucula The hinge plate has two series of taxodont teeth. mariae Nolf, 2005; Phenacovolva patriciae Nolf, The number and disposition of the taxodont teeth 2008 and Pteropurpura fairiana Houart, 1979 in any species is so variable that we were not were collected. Among these samples we found able to make use of it in identifying the one specimen of a Glycymeris sp. identical with specimens. For that reason no detailed those from NW Africa. However, we failed in photographs of the taxodont teeth have been obtaining specimens from the fisheries and included. expeditions in the Gulf of Guinea. Finally we will treat the presence of a very Type Family GLYCYMERIDIDAE Newton, 1916 unusual Glycymeris sp., actually only known Glycymeris da Costa, 1778 from one specimen, living off the Angolese coast. Type species: Arca glycymeris Linnaeus, 1758 Diagnosis: (by absolute tautonomy: ICZN Opinion 1414 - The family GLYCYMERIDIDAE is what we call a 1986). difficult mind-breaking family as many species are not common and many “common” species Glycymeris rafaelmesai sp. nov. are misunderstood, certainly when it concerns (Pl. I, Figs 1-5; Pl. II, Figs 6-11; Pl. III, Figs 12- West African and European species. 16; Pl. IV, Figs 17-21; Pl. V, Figs 22-25; This family is only represented by the genus Pl. VI, Figs 26-29; Pl. VII, Figs 30-33; Pl. VIII, Glycymeris in West African waters and contains Figs 34-38; Pl. IX, Figs 39-42; Pl. X, Figs 43-46; about six different species. They live from Pl. XI, Figs 47-50; Pl. XII, Figs 51-52) subtidal to deep water shallowly burrowed in sandy gravel and sandy or muddy bottoms. Type material: Shells are equivalve, equilateral or unequilateral, Holotype: La Burrera, La Graciosa, Lanzarote, circular or subcircular, occasionally posteriorly Canary Islands. Depth: 25 m. On sand H. 43.18 angled. Usually thick shells, rather smooth or mm L. 47.23 mm. RBINS (MT 2831, I.G. 32407). slightly ribbed. Ex CRM. Pl. III, Figs 12-16. The umbo is always opisthogyrate, which means Paratype 1: Charco del Palo, Mala, Lanzarote, that the beaks are turned towards the posterior Canary Islands. Dived at a depth of 25-35 m. On end of the valves. The height and width of the sand close to underwater caves. H. 43.46 mm L. ligamental area are variable within the species, 43.18 mm. CFSG. Pl. I, Figs 1-5. depending on the growth stage of the individual Paratype 2: Charco del Palo, Mala, Lanzarote, specimens. This area can be ornamented with Canary Islands. Dived at a depth of 25-35 m. On grooves. The ligamental condition in West sand close to underwater caves. H. 40.83 mm L. African Glycymeris is amphidetic, except in 40.52 mm. CRM. Pl. II, Figs 6-11. Glycymeris sp. Paratype 3: Dakar, Senegal. H. 37.31 mm L. Most of them have a cancellate microsculpture 39.52 mm. CFN. Pl. IV, Figs 17-21. covered with fine periostracal hairs with a velvety Paratype 4: Dakar, Senegal. H. 40.68 mm L. appearance. The microsculpture of each West 41.11 mm. CFS. Pl. V, Figs 22-25. African Glycymeris is a very unique and constant Paratype 5: Trawled by the ‘Sampayo’ between characteristic for each species and not variable 300-400 m, NW of Nouakchott, Mauritania. H. at all. It offers us a good identification tool. This 35.24 mm L. 37.01 mm. CFD. Pl. VI, Figs 26-29. structure is linked to the implantation of the Paratype 6: Trawled by the ‘Sampayo’ between periostracum. Smooth shells (Glycymeris sp.) 300-400 m, NW of Nouakchott, Mauritania. H. carry either a very fine periostracum or none at 49.47 mm L. 51.42 mm. CFD. Pl. VII, Figs 30-33. all. Neptunea, 12(2) 1 September 2013 2 Paratype 7: Trawled by the ‘Madroa’ between totally rusty coloured, probably caused by a 67-85 m deep, offshore La Güera, Western ferruginous bottom. In the latter specimens many Sahara. H. 61.85 mm L. 60.02 mm. CFD. Pl. VIII, brown radial stripes run from the beaks towards Figs 34-38. the lower margins. Even in light coloured Paratype 8: Trawled by the ‘Madroa’ between specimens radiating dark yellow lines are clearly 67-85 m deep, offshore La Güera, Western visible. Sahara. H. 66.95 mm L. 67.24 mm. CFD. Pl. IX, The interior of the shell is creamy white, partly or Figs 39-42. even almost completely dark brown coloured. Paratype 9: off Hotel Gran Melia Salinas, Veríl de los Ancones, Costa Teguise, Lanzarote, Measurements: H. 35-67 mm L. 37-67 mm. Canary Islands. Dived at a depth of 40 m near underwater caves. One valve. H. 65.66 m L. Derivation of name: The name was chosen in 64.38 mm. CRM. honour of Rafael Mesa (Lanzarote, Canary Paratype 10: Veríl de la Marina, Arrecife, Islands, Spain) who dived some specimens of Lanzarote, Canary Islands.