And Clavatula Hupferi

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

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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.

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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. Dived near the new species and who offered many fine underwater caves at a depth of 25 m. On sand. shells from the Canaries for study. One valve. H. 49.54 m L. 51.50 mm. CRM. Paratype 11: off Cabo Blanco, Mauritania, NW Habitat: In sand at a depth of 20-40 m in the Africa. Trawled at a depth of 60 m. 1979. H. Canary Islands. Some specimens have been 45.06 mm L. 43.91 mm. CFN. Pl. X, Figs 43-46. trawled at 67-85 m (Western Sahara) and even Paratype 12: off Cabo Blanco, Mauritania, NW at 300-400 m off the Atlantic coast of Mauritania. Africa. Trawled at a depth of 60 m. 1979. H. 45.06 mm L. 43.91 mm. CFN. Pl. XI, Figs 47-50. Locus typicus: Lanzarote, Canary Islands, Paratype 13: Moita Seca, Angola. Trawled by Spain. Belgian fishermen (PEMARCO) at a depth of 75 m. 1973. H. 44.11 mm L. 43.81 mm. CFN. Pl. Geographic range: This species is found in the XII, Figs, 51-52. Canary Islands (Lanzarote) and along the E Atlantic coasts of Mauritania, Western Sahara, Description: The shell is solid and heavy, Senegal and as south as Angola but no reports equivalve, not gaping, globular and equilateral. from the Gulf of Guinea are known. The valves are thick and almost subcircular in outline. The posterior shell margin is acute and Discussion: The new species can be compared slightly truncated, the anterior one is nearly with other Glycymeris-species living in the perfectly rounded. This results in a broader Atlantic Ocean. Only the main differences are dorsal area than a ventral side. Sometimes even mentioned here. a slight ridge runs from the umbo to the posterior In the W Atlantic: ventral angle giving the shell a mid-posterior - Glycymeris americana (Defrance, 1826) humped aspect. The umbones are opisthogyrate, (Pl. XIII, Figs 53-56): only juveniles can quite convex but small and clearly projecting be confused with adults of G. above the hinge line. The ligamental area is rafaelmesai; the taxodont teeth are more amphidetic: the beaks are central, nearly prominent; the outer surface has always reaching one another. The hinge plates are a pattern of brown blotches and strong, arched with two subequal series of possesses broad radial ribs bearing fine taxodont teeth in each valve, each containing 9- riblets which are absent in G. 15 sharply defined teeth, the two series merging rafaelmesai; the interior is white. into each other by means of a narrow zone - Glycymeris decussata (Linnaeus, 1758) consisting of 2-5 minute residual teeth. Ligament (Pl. XIV, Figs 57-58): with a circular embedded in a broad triangular pit below and on outline and opisthogyrate umbones; either side of the beaks. lateral teeth on both sides of umbo The microsculpture consists of very fine chevron shaped, semi-erect in the concentric undulating ribs. No radial grooves can central area; sculpture of numerous be observed, so no reticulated pattern is visible. prominent radial ribs and very fine Sinuous growth stages are sunken and clear. concentric threads giving the outer The remaining olive-coloured periostracum about surface a reticulated appearance absent the margins and in the grooves of the growth in G. rafaelmesai; brown zigzag stages is velvety and fibrous. The inner ventral maculations throughout the whole margin shows numerous deep grooves. surface. The colour is off-white to cream, sometimes with - Glycymeris undata (Linnaeus, 1758) (Pl. faint traces of thin brown zigzag lines in the XIV, Figs 59-60): a species with irregular umbonal region. Some specimens are partly or zigzag bands of brown blotches on the

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surface covered with a hair-type treated as juveniles of G. glycymeris as a periostracum; sculpture of distinct result of the cancellate microsculpture. crowded, furrowed radial ribs in contrast We possess representatives of G. to the commarginal concentric growth vanhengstumi from Morocco. The real lines in G. rafaelmesai. status of this species will be treated in a In the E Atlantic: next paper. - Glycymeris concentrica (Dunker, 1853) - Glycymeris nummaria (Linnaeus, 1758): (Pl. XV, Figs 61-66; Pl. XVI, Figs 67-74): more inflated, roundish quadrangular in the outline is obliquely truncated shape; radial ribs alternating with rather posteriorly; amphidetic ligamental strongly expressed light-coloured position; sculpture with many concentric grooves; purplish-reddish-brown; rather cords crossed by broader brown weak large (max. size: 75-86 mm). radiating grooves on a mostly uniform - Glycymeris pilosa (Linnaeus, 1767): tan surface. umbones strongly opisthogyrate; - Glycymeris formosa (Reeve, 1843) (Pl. prosodetic ligament; hairy dark-brown to XVII, Figs 75-79; Pl. XVIII, Figs 80-84; black periostracum: the hairs end in a Pl. XIX, Figs 85-86; Pl. XX, Figs 87-91; sharp point and bend back to the top of Pl. XXI, Figs 92-97): nearly circular but the shell; primary ribs split in 4-6 posteriorly slightly truncated; flatter than secondary ribs from the slightly convex G. concentrica; amphidetic ligamental beaks onwards; colour varies from light position; faint reticulated network of very brown to very dark brown and nearly weak radial threads and many irregular black, especially at the posterior side of flattened concentric ribs; pattern of the interior of the valves; this is mainly a radiating violet-brown flammules and Mediterranean species. stripes running over the whole surface - Glycymeris scripta (von Born, 1778) (Pl. from the umbones to the ventral margins XXII, Figs 98-102; Pl. XXIII, Figs 103- on an off-white background often shaded 108): circular outline; opisthogyrate with tan brown especially in the middle of umbones; ligamental condition: mostly the shell; the periostracum is similar to prosodetic; distinct homogenous network the coating in G. rafaelmesai, G. created by the intersection of numerous concentrica and G. scripta. In G. fine concentric and radiating threads; a rafaelmesai the olive colour of the pattern of 10-15 irregular intermittent periostracum is paler; this species is brown zigzag lines on a yellowish white restricted to the Cape Verde Islands and background arranged from the anterior the Gulf of Guinea. to the posterior side, some specimens - Glycymeris glycymeris (Linnaeus, 1758): may be provided with additional radiating both thick and solid specimens, thinner brown streaks on a light-brown and lighter shells may be found background. depending on the locality, while this - Glycymeris stellata (Bruguière, 1789) (= characteristic is rather constant in the G. vovan Lamy, 1912) (Pl. XXIV, Figs new species (limited to solid and heavy 109-113; Pl. XXV, Figs 114-115): with a ones); shells may be inflated or circular outline, valves slightly truncated; compressed, outline circular or obliquely amphidetic ligament; densely reticulated subovate; the periostracum is dark structure of many irregular concentric brown and frequently retained about the ribs and very fine radiating threads; margins; the colour is as variable as the background colour is creamy white, but shape varying between nearly nearly completely covered – except at completely brown shells and yellowish the umbones - by uniformly tan, regular white shells with zigzag markings, zigzag lines and darker brown radiating flammules or stripes: this variability is so lines or flecks especially visible at the extreme that some specimens can be ventral margins. The umbones are confused with G. formosa and G. scripta typically showing a creamy white star. but never with G. rafaelmesai n. sp. - Glycymeris vanhengstumi Goud & Conclusion: There are enough differences Gulden, 2009 shows similar between the several West-African Glycymeris- characteristics as G. glycymeris. This species to conclude that Glycymeris rafaelmesai small shell (30-50 mm) was described as is a separate species with a range from a new species from Madeira, the Mauritania, the Canary Islands and Senegal Selvagens and the Canary Islands. So towards the north of Angola. It lives in sand and far, specimens of this species had been probably also in ferruginous bottoms at depths

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between 20-400 m. The velvety and fibrous Distributional range: Cape Verde Islands, periostracum together with the structure of the Principe Island, São Tomé, Ile Banié, Gabon. shell which shows a commarginal ribbing and Outline: nearly circular but posteriorly truncated; only consist of concentric undulating growth lines flatter than G. concentrica. is unique among the other West-African Ligament condition: amphidetic. members of GLYCYMERIDIDAE. All the other Microsculpture: faint reticulated network of very species have a reticulated structure with a weak radiating threads and irregular concentric cancellate network of intersecting radial and flattened ribs. commarginal ribs. At first sight it could be mixed Periostracum: The velvety periostracum is up with G. scripta but it can easily be mostly restricted to the margins even in fresh differentiated by its outline, its commarginal collected specimens; it is similar to the coating in ribbing and its colour. G. rafaelmesai, G. concentrica and G. scripta, but in G. rafaelmesai the olive colour is paler. Glycymeris concentrica (Dunker, 1853) Colour: pattern of radiating violet-brown (Pl. XV, Figs 61-66; Pl. XVI, Figs 67-74) flammules and stripes running over the whole surface from the umbones to the ventral margins = Pectunculus concentrica Dunker, 1853 on an off white background often shaded with tan brown especially in the middle of the shell. Distributional range: Mauritania, Canary Measurements: 30-80 mm. Islands, Cape Verde Islands, Senegal, Guinea, Remarks: G. formosa differs from G. stellata by Ivory Coast, Ghana, Principe Island, Gabon, the smaller number of - longer - internal Angola. crenulations. Outline: circular, with the posterior end slightly produced and obliquely truncated. The form G. formosa var. tumida Dautzenberg Ligamental condition: amphidetic (central & H. Fischer, 1906 (Pl. XX, Figs 87-91; Pl. XXI, umbones). Figs 92-97) is differentiated by its swollen look Microsculpture: reticulated pattern of an and the dark-red coloured flammules instead of enormous number of very regular concentric fine violet. cords crossed by a smaller number of broad flattened radiating ribs. Glycymeris scripta (von Born, 1778) Periostracum: In contrast to the other West (Pl. XXII, Figs 98-102; Pl. XXIII, Figs 103-108) African species the dark brown velvety periostracum is rather resistant. = Arca scripta von Born, 1778 Colour: rather variably coloured, some specimens may be completely brown, others are Distributional range: Canary Islands, Morocco, dark brown in the middle with white areas at both Senegal, Sierra Leone. the anterior and posterior side, occasionally Outline: almost circular. specimens are completely creamy white crossed Ligamental condition: mostly prosodetic, by brown interrupted lines. Exceptionally, shells slightly amphidetic in very adult, large possess zones of brown flammules on a light specimens. background. Many specimens show a brown Microsculpture: homogenous cancellate blotch near the umbo at the posterior side. network created by the intersection of numerous Measurements: 20-45 mm. fine concentric threads and equal narrow Remark: For a more detailed discussion about radiating ribs. the real status of this species-name we refer to Periostracum: olive-brown, velvety and fibrous Huber (2010). similar to the one in Glycymeris rafaelmesai. Colour: A pattern of 10-15 intermittent reddish Glycymeris formosa (Reeve, 1843) brown or dark brown undulating zigzag lines is (Pl. XVII, Figs 75-79; Pl. XVIII, Figs 80-84; irregularly arranged on a yellowish white Pl. XIX, Figs 85-86; Pl. XX, Figs 87-91 background from the anterior to the posterior Pl. XXI, Figs 92-97) margin, occasionally provided with additional radiating brown streaks on a light-brown = Pectunculus formosus Reeve, 1843 background. = Glycymeris formosa tumida (Dautzenberg, Measurements: 40-70 mm. 1906) Remark: Clearly depicted by von Born, 1780 and = Pectunculus formosa var. tumida Dautzenberg Reeve, 1843 this species was later on placed in & H. Fischer, 1906 [non Dunker, 1871] the Caribbean Sea by Lamy who did not = Pectunculus formosa var. tumida Dautzenberg correctly recognize Adanson’s Le Vovan. He & H. Fischer, 1906 considered it distinct from scripta and created Pectunculus vovan “Adanson” Lamy, 1912

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referring to Adanson, fig.10. However, Adanson’s Gmelin, 1791 “V. testa orbiculari laevi aurea, collection was rediscovered in 1939-1941 and stella ad umbonem candida”. This is a treated by E. Fischer-Piette (1942). According to characteristic species known but not depicted the text and the figure Le Vovan proved to be the nor given a name by Adanson. The earliest use scripta of von Born: ‘small red-brown zigzag of the name ‘stellata’ was as Arca by Bruguière, lines’. Fischer-Piette figured this shell on pl. VXI, 1789. Reeve (1843) depicted the correct fig.5. stellatus, but with an erroneous locality. Smith (1885) compared it with European species and reported it from the Canaries. Tomlin and Shackleford (1914) applied the name Glycymeris stellatus (Gmelin, 1791) and reported it from São Tomé, Principe, Senegal and Madeira. Nordsieck (1969) confused Glycymeris scripta with Glycymeris stellata. The description (14.04) refers to G. stellata but the shell figured in plate IV, 14.04 is G. scripta. Gómez & Sánchez (1997) mention G. stellata from the Canaries but discuss and figure G. scripta (p.131). Gómez and Pérez (2011) made the same mistake. This is clearly a distinct species differentiated Glycymeris stellata (Bruguière, 1789) from G. scripta by its colour, its less globose (Pl. XXIV, Figs 109-113; Pl. XXV, Figs 114-115) form, a larger number of taxodont teeth and its main commarginal microsculpture. G. scripta is = Arca stellata Bruguière, 1789 more restricted to NW African waters. It differs = Pectunculus stellatus (Bruguière, 1789) from G. formosa by the larger number of – = Venus stellata Gmelin, 1791 shorter – internal crenulations. = Pectunculus vovan Lamy, 1912 Glycymeris sp. Distributional range: Madeira, Canary Islands, (Pl. XXVI, Figs 116-119) Mauritania, Senegal, Sierra Leone, Principe Description: Small, solid shell with flattened Island, Cameroon and Angola. valves. Outline subovate, posteriorly truncated. Outline: almost circular but broader than high. The ligamental position is prosodetic (ligament Valves obtusely truncated. on the anterior side of the umbones). The hinge Ligament condition: amphidetic. plate has two series of taxodont teeth, the Microsculpture: dense reticulated structure of anterior part with about 10 teeth nearly irregular concentric cords crossed by very fine continuously proceeding in a posterior series radiating threads. Clear growth stages. with 14-15 smaller teeth. The external surface of Periostracum: dark olive-brown, velvety and the valves is glossy, with practically no traces of fibrous restricted to the margins of the valves. a network, only faint radial ribs, crossed by Colour: The background colour is yellow or microscopic concentric threads and growth lines. rusty-brown, nearly completely covered – except Evidently there is no periostracum. at the umbones - with an enormous number of The colour of the shell is bluish grey with brown uniformly tan concentric, regular, undulating streaks and zigzag markings all over the surface, zigzag lines merging in a nearly brown zone at especially provided with a darker blotch the bottom of the valves. In this area, dark brown posteriorly. The interior of both valves is brilliant lines or narrow flecks are often present at the and provided with a well-defined central brown ventral margins. The umbones are typically blotch. showing a creamy white star and the pattern of Measurements: H. 20.33 mm L. 21.16 mm. brown lines is sometimes interrupted by tiny pale Locus typicus: Sumbe (the former Novo figures with an irregular shape. Redondo till 1975), Angola. Measurements: 50-70 mm. Discussion: This is a unique shell easily Remarks: From Adanson (1757) we learn that differentiated from other West African more specimens were present in the sample of Glycymeris-species by its distinct characteristics: Le Vovan which had ‘a white umbo with the look prosodetic ligament, glossy surface without of a star … while the remaining part of the periostracum and special bluish grey colour. surface is crossed by three to four large circular Unfortunately, only one specimen is known (coll. dark-brown zones’. Later on, Lamy confirmed F. Nolf), making the description as a new species that several specimens had been mixed up and provisionally impossible at present. Moreover, the shell on pl.3, fig. 5 instead is Venus stellata this may be a juvenile specimen.

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Identification key to the endemic West African species of the genus Glycymeris: 1 Ligamental condition: amphidetic ………………………………………………………………… 2 - Ligamental condition: prosodetic …………………………………………………………………. 7 2 Commarginal microsculpture ...... 6 - Reticulated microsculpture …………………………………………………………………...... 3 3 Reticulated microsculpture with distinct regular concentric cords very close together and broad flattened radial ribs ………………………………………………………………………...... 5 - Obscure reticulated microsculpture with very fine radiating threads and thicker irregular concentric cords ………………………………………………………………………………………4 4 Large number of short internal crenulations, interior mostly off-white, circular outline but broader than high, numerous radiating brown lines starting from a white star at the umbones ……………………………………………………………………….. …………...Glycymeris stellata - Smaller number of longer internal crenulations, interior with large purplish-brown blotch especially posteriorly, outline nearly circular or subovate, anterior part slightly truncated, brown flammules ……………………………………………………………...Glycymeris formosa 5 Posterior end slightly produced and obliquely truncated, velvety periostracum ……………………………………………………………………………… Glycymeris concentrica 6 Globular shell, from circular to subovate, some specimens may have a humped aspect at the posterior side, pale olive velvety periostracum ………………………. Glycymeris rafaelmesai 7 Equilateral, homogenous reticulated microsculpture with very fine radiating and concentric threads, circular outline, globose valves, olive-brown velvety periostracum, 10-15 intermittent brown undulating zigzag lines on a creamy or brownish background …... Glycymeris scripta - Largely inequilateral, surface of valves brilliant, no periostracum, very weak nearly invisible cancellate microsculpture, bluish grey ………………………………….. Glycymeris sp.

Geographical distribution of the genus Glycymeris in West Africa

G. concentrica G. formosa G. rafaelmesai G. scripta Glycymeris sp. G. stellata

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Acknowledgements: Special thanks go to Johan Verstraeten (Oostende, Belgium) for a critical lecture of the manuscript and to David Monsecour (Aarschot) for correcting the English text. Francisco Déniz (Gran Canaria), Francisco Sicilia Guillén (Lanzarote) and Rafael Mesa (Lanzarote) were so kind as to offer study material in loan.

References: Adanson, M., 1757. Histoire naturelle du Sénégal. Coquillages. Avec la relation abrégée d’un voyage fait en ce pays, pendant les années 1749, 50, 51, 52 & 53. Paris. Ardovini, R. & Cossignani, T., 2004. West African Seashells. Ancona. 319 pp. CLEMAM. Unitas Malacologia Check List of European Marine Mollusca. Internet site (current URL http://www.somali.asso.fr/clemam/index.clemam.html). Last search September 2013. Da utzenberg, Ph., 1910. Contribution à la faune malacologique de l’Afrique occidentale. Actes de la société Linnéenne de Bordeaux 1910, Extrait. Y. Cadoret, Bordeaux. 174 pp. Dautzenberg, Ph., 1912. Mission Gruvel sur la côte occidentale d’Afrique (1909-1910): Mollusques Marins, Extrait. Annales de l’Institut Océanographique, Paris. 3: 1-111. Dautzenberg, Ph. & Fischer, H., 1906. Mollusques provenant des dragages effectués à l’ouest de l’Afrique pendant les campagnes scientifiques de S.A.S. le Prince de Monaco. Résultats des campagnes scientifiques accomplies sur son yacht par Albert 1er Prince souverain de Monaco, publiés sous sa direction avec le concours de M. Jules Richard. Imprimerie de Monaco, Monaco. Vol.32: 1-125, 5 pls. Fischer-Piette, E., 1942. Les Mollusques d’Adanson. Rennes. 103-374, pls I-XVI. Fischer-Piette, E. & Nicklès, M., 1946. Mollusques nouveaux ou peu connus des côtes de l’Afrique occidentale. Journal de Conchyliologie, 87(2): 45-82. Gómez, R. & Pérez, J.M., 1997. Moluscos Bivalvos de Canarias. Cabildo Insular de Gran Canaria. Las Palmas. 425 pp. Gómez, R. & Pérez, J.M., 2011. Bivalvia: pp. 301 – 389. Parte 6: In Rolán, E. (coord.). 2011. Moluscos y conchas marinas de Canarias. ConchBooks, Hackenheim & Emilio Rolán, Vigo, 716 pp., 130 pls. Goud, J. & Gulden, G., 2009. Description of a new species of Glycymeris (Bivalvia: Arcoidea) from Madeira, Selvagens and Canary Islands. Zoologische Mededelingen, 83(33), 29.viii: 1059-1066. Leiden. Huber, M., 2010. Compendium of Bivalves. ConchBooks. Hackenheim. 901 pp. ICZN, 1986. Opinion 1414. Panopea Menard de la Groyes, 1807 (Mollusca, Bivalvia): conserved. Bull. of Zoological Nomenclature, 43(3): 258-261. London. Nicklès, M., 1947. La Collection de Mollusques testacés marins de l’I.F.A.N. Publications I.F.A.N., Catalogue I. Dakar. Nicklès, M., 1950. Mollusques testacés marins de la côte occidentale d’Afrique. Manuel Ouest- Africains. Vol.II: Lechevalier, Paris. 269 pp, textfigs. Nicklès, M., 1952. Mollusques testacés marins du littoral de l’A.E.F. Journal de Conchyliologie, vol. XCII: 143-154. Extrait. Nicklès, M., 1955. Scaphopodes et Lamellibranches récoltés dans l’Ouest Africain. Atlantide Report N°3. Scientific Results of the Danish Expedition to the Coasts of Tropical West Africa 1945-1946. Danish Science Press, Copenhagen. 93-237. 41 figs. Nieulande, F.A.D., van & Moerdijk, P.W., 1999. Europese Glycymerididae, overzicht van de vanaf het Oligoceen in Europa voorkomende soorten. De Kreukel, extra edition: 1-27, 28 plates. Nobre, A., 1937. Moluscos testáceos marinhos do Arquipélago da Madeira. Memorias e Estudos do Museu zoológico da Universidade de Coimbra, sér. I, n° 98. Nordsieck, F., 1969. Die europäischen Meeresmuscheln (Bivalvia), vom Eismeer bis Kapverden, Mittelmeer and Schwarzes Meer. Gustav Fischer Verlag, Stuttgart. 256 pp. Pasteur-Humbert, C., 1962. Les Mollusques Marins Testacés du Maroc. II.- Les Lamellibranches et les Scaphodes. Travaux de l’Institut scientifique chérifien, série Zoologie n° 28. Rabat. 184 pp. Poppe, G.T. & Goto, Y., 1993. European Seashells, Volume II (Scaphopoda, Bivalvia, Cephalopoda). Verlag Christa Hemmen, Wiesbaden, Germany. 221 pp. Reeve, L.A. (and G.B. Sowerby II), 1843. Monograph of the genus Pectunculus. Conchologica Iconica: or, Illustrations of the Shells of Molluscous Animals, Vol.1. London. Smith, E.A., 1885. Report on the Lamellibranchiata collected by H.M.S. Challenger during the years 1973-1876. In: Report on the scientific results of the voyage of H.M.S. Challenger during the years 1873-1876. Zoology. London, 13(35): 1-341. Tomlin, J.R. le B. & Shackleford, L.J., 1914-1915. The marine mollusca of São Thomé, 1. Journal of Conchology, 14: 239-256 (1914); 267-276 (1915).

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5 1

. Plate I. Figs 1-5: Glycymeris rafaelmesai sp. nov. Charco del Palo, Mala, Lanzarote, Canary Islands. Dived at a depth of 25-35 m. On sand, close to underwater caves. H. 43.46 mm L. 43.18 mm. Paratype 1. CFSG; 1: RV; 2: LV; 3: inside of RV; 4: inside of LV; 5: detail of velvety periostracum.

Neptunea, 12(2) 1 September 2013 9

6 11

Plate II. Figs 6-11: Glycymeris rafaelmesai sp. nov. Charco del Palo, Mala, Lanzarote, Canary Islands. Dived at a depth of 25-35 m. On sand, close to underwater caves. H. 40.83 mm L. 40.52 mm. Paratype 2. CRM; 6: LV; 7: RV; 8: inside of LV; 9: inside of RV; 10: top view; 11: detail of velvety periostracum.

Neptunea, 12(2) 1 September 2013 10

16 12

Plate III. Figs 12-16: Glycymeris rafaelmesai sp. nov. La Burrera, La Graciosa, Lanzarote, Canary Islands. Dived at a depth of 25 m. On sand. H. 43.18 mm L. 47.23 mm. Holotype. RBINS (MT 2831); 12: LV; 13: RV; 14: inside of LV; 15: inside of RV; 16: top view.

Neptunea, 12(2) 1 September 2013 11

Plate IV. Figs 17-21: Glycymeris rafaelmesai sp. nov. Dakar, Senegal. H. 37.31 mm L. 39.52 mm. Paratype 3. CFN; 17: LV; 18: RV; 19: inside of LV; 20: inside of RV; 21: top view.

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Plate V. Figs 22-25. Glycymeris rafaelmesai sp. nov. Dakar, Senegal. H. 40.68 mm L. 41.11 mm. Paratype 4. CFS; 22: LV; 23: RV; 24: inside of LV; 25: inside of RV.

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Plate VI. Figs 26-29: Glycymeris rafaelmesai sp. nov. NW of Nouakchott, Mauritania. Trawled at 300- 400 m. November 2000. H. 35.24 mm L. 37.01 mm. Paratype 5. CFD; 26: LV; 27: RV; 28: inside of LV; 29: inside of RV.

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Plate VII. Figs 30-33: Glycymeris rafaelmesai sp. nov. NW of Nouakchott, Mauritania. Trawled at 300- 400 m. November 2000. H. 35.24 mm L. 37.01 mm. Paratype 6. CFD; 30: LV; 31: RV; 32: inside of LV; 33: inside of RV.

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34 38

Plate VIII. Figs 34-38: Glycymeris rafaelmesai sp. nov. Offshore La Güerra, Western Sahara. Trawled by fishermen at a depth of 67-85 m. March 1998. H. 61.85 mm L. 60.02 mm. Paratype 7. CFD; 34: LV; 35: RV; 36: inside of LV; 37: inside of RV; 38: details of umbo and ligamental area.

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Plate IX. Figs 39-42: Glycymeris rafaelmesai sp. nov. Offshore La Güerra, Western Sahara. Trawled by fishermen at a depth of 67-85 m. March 1998. H. 66.95 mm L. 67.24 mm. Paratype 8. CFD; 39: LV; 40: RV; 41: inside of LV; 42: inside of RV.

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Plate X. Figs 43-46: Glycymeris rafaelmesai sp. nov. Off Cabo Blanco, Mauritania, NW Africa. Trawled by fishermen at a depth of 60 m. March 1979. H. 45.06 mm L. 43.91 mm. Paratype 11. CFN; 43: LV; 44: RV; 45: inside of LV; 46: inside of RV.

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Plate XI. Figs 47-50: Glycymeris rafaelmesai sp. nov. Off Cabo Blanco, Mauritania, NW Africa. Trawled by fishermen at a depth of 60 m. March 1979. H. 48.62 mm L. 47.98 mm. Paratype 12. CFN; 47: LV; 48: RV; 49: top view; 50: details of microsculpture. .

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Plate XII. Figs 51-52: Glycymeris rafaelmesai sp. nov. Moita Seca, North, Angola. Trawled by Belgian fishermen (PEMARCO) at a depth of 75 m. 1973. H. 43.05 mm L. 44.36 mm. Paratype 13. CFN; 51: LV; 52: RV.

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Plate XIII. Figs 53-56: Glycymeris americana (Defrance, 1826). Dredged off Isla de Veraguas, E Panama at a depth of 16 m. All specimens are juvenile. CFN; 53-54: H. 33.17 mm L. 35.89 mm; 53: LV; 54: RV; 55-56: H. 31.02 mm L. 35.13 mm; 55: LV; 56: RV.

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Plate XIV. Figs 57-58: Glycymeris decussata (Linnaeus, 1758). Port Louis, Grande Terre, Guadeloupe, Lesser Antilles. Dived. February 1972. H. 31.74 mm L. 32.11 mm. CFN; 57: LV; 58: RV; Figs 59-60: Glycymeris undata (Linnaeus, 1758). Porto Bello, E Panama. Dredged at a depth of 60 m. H. 37.63 mm L. 40.05 mm. CFN; 59: LV; 60: RV.

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61 62

63 64

65 66

Plate XV. Figs 61-66: Glycymeris concentrica (Dunker, 1853). Dakar, Senegal. Dredged at a depth of 11 m. December 1978. CFN; 61-62: H. 33.40 mm L. 34.60 mm; 61: LV; 62: RV; 63-64: H. 33.47 mm L. 36.85 mm; 63: LV; 64: RV; 65-66: H. 34.80 mm L. 36.89 mm; 65: LV; 66: RV.

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67 68

73 69 70

71 72

Plate XVI. Figs 67-74. Glycymeris concentrica (Dunker, 1853). CFN; 67-68: Ivory Coast. Trawled by fishermen. 1976. H. 32.69 mm L. 37.76 mm; 67: inside of LV; 68: inside of RV; 69-72: Luanda, Angola. Dived in sand at a depth of 6 m; 69-70: H. 31.13 mm L. 33.87 mm; 69: LV; 70: RV; 71-72: H. 39.15 mm L. 43.47 mm; 71: LV; 72: RV; 73: details of periostracum; 74: details of microsculpture.

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Plate XVII. Figs 75-79: Glycymeris formosa (Reeve, 1843). Matiota Bay, Mindelo, São Vicente, Cape Verde Islands. Dredged at 0.5 mile offshore. CFN; 75-76: H. 29.26 mm L. 30.30 mm; 75: LV; 76: RV; 77-78: H. 40.91 mm L. 43.62 mm; 77: LV; 78: RV; 79: details of periostracum.

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80 84

small number of long crenulations

Plate XVIII. Figs 80-84: Glycymeris formosa (Reeve, 1843); 80-81: Matiota Bay, Mindelo, São Vicente, Cape Verde Islands. Dredged at 0.5 mile offshore. CFN. H. 63.65 mm L. 66.13 mm; 80: LV; 81: RV; 82-83: off Porto Novo, Santo Antão Island, Cape Verde Islands. Dived at a depth of 26 m. May 2008. H. 60.29 mm L. 64.84 mm; 82: inside of LV; 83: inside of RV; 84: details of microsculpture.

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Plate XIX. Figs 85-86: Glycymeris formosa (Reeve, 1843). Off Porto Novo, Santo Antão Island, Cape Verde Islands. Dived at a depth of 26 m. May 2008. CFN. H. 69.80 L. 75.45 mm; 85: LV; 86: RV.

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Plate XX. Figs 87-91: Glycymeris formosa var. tumida Dautzenberg & H. Fischer, 1906. (Poli, 1791). Porto Grande, São Vicente, Cape Verde Islands. Dredged at a depth of 9 m. September 1976; 87-88: H. 54.31 L. 57.35 mm; 87: LV; 88: RV; 89-91: H. 58.30 mm L. 59.27 mm; 89: LV; 90: RV; 91: top view.

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92 93

94 95

Plate XXI. Figs 92-97. Glycymeris formosa var. tumida Dautzenberg & H. Fischer, 1906. Principe Island, Gulf of Guinea. Dived at a depth of 10 m. In sand. December 2009. CFN; 92-93: H. 37.09 mm L. 38.55 mm; 92: LV; 93: RV; 94-97: H. 41.80 mm L. 43.64 mm; 94: LV; 95: top view; 96: side view, 97: RV.

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98 102

100

largely prosodetic ligament condition

101

Plate XXII. Figs 98-102: Glycymeris scripta (von Born, 1778). Off Cabo Blanco, Mauritania. Trawled by fishermen at a depth of 60 m. 1979. CFN; 98-99: H. 31.56 mm L. 33.31 mm; 98: LV; 99: RV; 100- 102: H. 39.67 mm L. 42.79 mm; 100: LV; 101: inside of RV; 102: details of microsculpture.

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103 108

104

105

106

107

Plate XXIII. Figs 103-108: Glycymeris scripta (von Born, 1778). Bay of Hann, Senegal. Dredged at a depth of 15 m. CFS; 103-104: H. 45.98 L. 50.73 mm; 103: LV; 104: RV; 105-107: H. 42.55 mm L. 44.56 mm; 105: LV; 106: RV; 107: inside of RV; 108: details of periostracum and microsculpture.

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109 112

111

113

large number of short crenulations 110

Plate XXIV. Figs 109-113: Glycymeris stellata (Bruguière, 1789). Bay of Hann, Dakar, Senegal. Dredged at a depth of 11 m. In sand. November 1979. CFN; 109: LV; 110: inside of RV; 111: details of the umbonal region; 112: details of periostracum; 113: details of microsculpture.

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114

115

Plate XXV. Figs 114-115: Glycymeris stellata (Bruguière, 1789). Bay of Hann, Dakar, Senegal. Dredged at a depth of 11 m. In sand. November 1979. CFN; 114: LV; 115: RV.

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116

117

118

119

Plate XXVI. Figs 116-119. Glycymeris sp. Sumbe, Angola. H. 20.33 mm L. 21.16 mm. CFN; 116: LV; 117: RV; 118: inside of LV; 119: inside of RV.

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