Comparison of Some Interesting Molluscs, Trawled by the Belgian Fishery in the Bay of Biscay, with Similar Representatives from Adjacent Waters: Part II
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Comparison of some interesting molluscs, trawled by the Belgian fishery in the Bay of Biscay, with similar representatives from adjacent waters: part II Frank Nolf 1 & Jean-Paul Kreps 2 1 Pr. Stefanieplein, 43/8 – B-8400 Oostende [email protected] 2 Rode Kruisstraat, 5 – B-8300 Knokke-Heist [email protected] Keywords: Bay of Biscay, W. France, Belgian reported from Western Europe, except fishery, Gastropoda, molluscs. northwards up to Vigo (NW Spain) (Rolán, 1983; Dautzenberg 1927). This species is not Abstract: In this paper some of the most mentioned by Bouchet & Warén (1993) because interesting gastropod molluscs, trawled by the it is not considered to be a deep-water species. It Belgian fishery in the Bay of Biscay during the is rarely found in the Bay of Biscay (Plate XXII, last decade, are briefly described yet Figs 161-164; Plate XXIII, Fig 165) and it lives on comprehensively figured. A comparison is made all kinds of bottoms of the continental plate. with similar specimens from North Atlantic Specimens were collected by the Belgian fishery waters, the Mediterranean Sea or West Africa. at depths of 90 to 160 m. Abbreviations: Galeodea rugosa (Linnaeus, 1771) FN: private collection of Frank Nolf. Plate XXV, Figs 173-176; Plate XXVI, Figs 177- H.: height. 180; Plate XXVII, Figs 181-182 JPK: private collection of Jean-Paul Kreps. JV: private collection of Johan Verstraeten. = Buccinum rugosum Linnaeus, 1771 L.: length. = Buccinum tyrrhenum Gmelin, 1791 PEMARCO: Pêche Maritime du Congo. = Cassidaria depressa Philippi, 1844 RBINS: Royal Belgian Institute for Natural Sciences, Brussels, Belgium. This species is differs from the similar G. echinophora (Linnaeus, 1758) by its regular and Description of species: equally spaced ridges. G. rugosa is larger and has a lighter colour. Most specimens have a light TONNIDAE shell, with a high spire. Knobs are generally absent, but sometimes traces of them are Semicassis saburon (Bruguière, 1792) present on the backside of the shell. The exact Plate XXII, Figs 161-164; Plate XXIII, Figs 165- identity of specimens of Galeodea that lack 168; Plate XXIV, Figs 169-172 tubercles but are common also in shallow waters of the Adriatic is a much discussed topic in = Cassidea saburon Bruguière, 1792 literature. These shells belong to G. echinophora = Cassis laevigatus Defrance, 1817 var. mutica Tiberi, 1863 or G. echinophora var. = Cassis pomum Schubert & Wagner, 1829 adriatica Coen, 1914 (Bouchet & Warén, 1993; = Cassis nucleus Küster, 1857 Settepassi, 1970). G. rugosa is less variable than = Cassis abbreviata Monterosato, 1878 G. echinophora, but nevertheless does it vary = Cassis platystomus Brugnone, 1880 enough to create confusion. Specimens from the = Cassis adansoni Locard, 1886 Ibero-Moroccan Gulf tend to develop an = Cassis saburoni Locard, 1886 undulating keel on the shoulder of the body- = Semicassis miolaevigatus Sacco, 1890 whorl, forming indistinct nodules, but the general appearance of the shells is like that of other S. saburon is mainly known from the areas. We have remarked the same aberration in Mediterranean Sea (Plate XXIV, Figs 169-171), specimens of G. keyteri (Kilburn, 1975), trawled the Canaries, the Cape Verde Islands (Plate at a depth of 700 m in the Strait of Mozambique XXIV, Fig. 172) and West Africa extending to (Nolf & Verstraeten, 2003). Angola (Plate XXIII, Figs 166-168). Seldom Neptunea, vol. 8, n°3 1 November 2009 1 Usually the colour of the shell is creamy white reasonably common occurrence is on the but light brown or pinkish shells are not southern part of the Bay of Biscay (Plate XXVIII, uncommon off the coast of NW Spain (Rolán, Figs 183-184; Plate XXIX, Figs 185-187). Only 1983) and W France. Full-grown ones can reach sporadically specimens are caught further north more than 120 mm in length. We show two giant (between Lands End and the Isles of Scilly, the specimens on Plate XXVII, Figs 181-182 Channel Islands). measuring 156.5 mm and 135 mm respectively. This rather variable and widespread species has received an enormous number of names, This species too is a rare mollusc in the Bay of probably exceeded only by those applied to Biscay (Plate XXV, Figs 173-176) at a depth of Ranella olearia (Linnaeus, 1758). It is beyond the 90-160 m. None have been reported by purpose of this paper to enumerate all these Dautzenberg (1927) in the waters off W France, synonyms, but we would like to mention and but Bouchet & Warén (1993) mention 23 illustrate some of the better known forms samples with good data in 290-1000 m and 8 formerly recognised as separate subspecies samples from old collections with less accurate (see Henning & Hemmen, 1993, amongst data. Its range extends from the southern others): extremities of the British Isles (Plate XXVI, Figs 177-178), through the western part of the - Charonia lampas lampas (Linnaeus, 1758) Mediterranean (Plate XXVI, Figs 179-180; Plate Plate XXVIII, Figs 183-184; Plate XXIX, Figs XXVII, Figs 181-182) as far south as southern 185-187; Plate XXX, Figs 188-189; Plate XXXI, Morocco. The southernmost record is 22°52’ N. Figs 190-191 (Bouchet & Warén, 1993). G. rugosa lives on a muddy bottom in deep water between 70 and This is the largest and heaviest form which 700 m. belongs to the Eastern Atlantic and western Mediterranean waters. Specimens measure from RANELLIDAE 120 to 350 mm, but shells of about 450 mm are also known (Franchini, 1974). It lives in deeper Charonia lampas (Linnaeus, 1758) waters in the northern part of its range. It may be Plate XXVIII, Figs 183-184; Plate XXIX, Figs collected from extreme low tide and as deep as 185-187; Plate XXX, Figs 188-189; Plate XXXI, 700 m, on rocky and less solid bottoms such as Figs 190-191; Plate XXXII, Figs 192-195; Plate gravel, sand and mud. In the East Atlantic the XXXIII, Figs 196-197 animals feed on the starfish Echinaster sepositus (Retzius, 1783) and on scallops. The shells from = Murex lampas Linnaeus, 1758 the Bay of Biscay are often covered with = Tritonium opis Röding, 1798 specimens of Neopycnodonte cochlear (Poli, = Murex gyrinoides Brocchi, 1814 1795) (Plate XXIX, figs 185-186). = Triton nodiferum Lamarck, 1822 The colour of the shells very often contains = Tritonium mediterraneum Risso, 1826 tinges of green, probably caused by algae. The = Triton ventricosum Grateloup, 1833 shells from the British Channel are generally = Triton ranelliforme Sismoda, 1846 completely ruined with encrustations (Plate = Triton glabrum Locard, 1886 XXIX, fig. 187). Charonia lampas is scattered throughout most of - Charonia lampas pustulata (Euthyme, the warm-temperate to subtropical waters, from 1889) the north-eastern Atlantic (from the British Plate XXXII, Fig. 192 Channel Islands, SW England and SW Ireland) as far south as Angola, Madeira, the Canary = Nyctilochus alfredensis Bartsch, 1915 Islands, the Cape Verde Islands and into the = Cymatium weisbordi Gibson-Smith & western Mediterranean Sea, but rarely on the Gibson-Smith, 1970 Azores. Further south it extends to Southern Africa, Tristan da Cunha and the Indian Ocean, Range: Southern Africa (Cape of Good Hope to the south-western Pacific (southern Queensland Natal, Tristan da Cunha, Indian Ocean). to SW Australia and New Zealand, the Philippines, Japan and Taiwan). It is not present From 90 to 220 mm, heavy but squat and in the Eastern Pacific waters of the American coarsely sculptured with strong varices and huge continent, but it is occasionally found along the shoulder tubercles. Strong teeth inside the outer Brazilian coast. It is also mostly absent from the lip. Basic colour dull brownish, bluish- and eastern Mediterranean, where it appears to have purplish-tinged and patterned with dark brown been replaced by Charonia variegata (Lamarck, markings. Columellar plicae whitish on the dark 1816). In the East Atlantic the northern limit of inner wall. Neptunea, vol. 8, n°3 1 November 2009 2 It differs from the Australian form C. lampas localities. The geographic races have been rubicunda (Perry, 1811) by its stronger nodules named on the basis of shallow-water forms, and more developed columellar plicae. whereas specimens from relatively deeper water (ca 100-300 m) are all closely similar to each - Charonia lampas rubicunda (Perry, 1811) other all around the world. That means that Plate XXXII, Figs 193-195; Plate XXXIII, Figs differences are caused by ecophenotypic rather 196-197 than to genetic variations. For instance light coloured, slender, weakly sculptured shells are = Triton australe Lamarck, 1822 typical of deep water anywhere. In the future it = Charonia lampas var. euclia Hedley, 1914 will turn out that the use of geographic = Charonia capax Finlay, 1927 subspecies names serves little purpose in most = Charonia capax euclioides Finlay, 1927 of the widely distributed RANELLIDAE. The use = Charonia euclia instructa Iredale, 1929 of the abovementioned names is no more than = Charonia powelli Cotton, 1957 an interim measure, reflecting an uncertain status. Range: Southwestern Pacific (Western Australia to southern Queensland, New Caledonia and Ranella olearia (Linnaeus, 1758) around both mainlands of New Zealand). Plate XXXIV, Figs 200-202; Plate XXXV, Figs From 120 to 160 mm, up to 260 mm (var. capax). 203-206; Plate XXXVI, Figs 207-210 Typical specimens are squat and low-spired. Spiral sculpture very coarse but shoulder = Murex olearium Linnaeus, 1758 nodules very weak or absent. Aperture = Murex reticularis Born, 1778 [non Linnaeus, subcircular, columella smooth except for a few 1758] weak anterior plicae and one parietal ridge. = Ranella gigantea Lamarck, 1816 Colour pinkish to orange. = Ranella ranina Lamarck, 1816 There are intergrades between this form and the = Gyrina maculata Schumacher, 1817 form described as C. powelli by Cotton (1957) = Murex mulus Dillwyn, 1817 from Western and South Australia. The latter is = Murex gyrinus de Blainville, 1825 [non more elongate, pale cream coloured to dark Linnaeus, 1758] brownish and bears stronger nodules and more = Murex boveus Risso, 1826 numerous columellar plicae.