Murexsul hexagonus ( Lamarck, 1816 )

Garrigues, Bernard & Merle, Didier, 2014, Nine new species of Muricidae Rafinesque, 1815 (Mollusca, Gastropoda) from the French Antilles, Zoosystema 36 (4), pp. 841-864 : 856-862

Murexsul hexagonus ( Lamarck, 1816)

( Figs 7 A-F; 12 E)

Murex hexagonus Lamarck, 1816: 5 , pl. 418, fig. 3a, b.

Murex hexagonus Lamarck, 1822: 169 .

Murex hexagonus – Smith 1939: 11, pl. 6, fig. 3.

Muricopsis oxytata sensu Abbott, 1974: 187 , fig. 1957, non Murex hexagonus oxytatus Smith, 1938 ; sensu Radwin & D’Attilio 1976: 169, pl. 27, fig. 5, non Murex hexagonus oxytatus Smith, 1938 ; sensu Fair 1976: 122, pl. 17, n° 226, non Murex hexagonus oxytatus Smith, 1938 ; sensu Abbott & Dance 1982: 144, non Murex hexagonus oxytatus Smith, 1938 ; Vokes 1994: 62, pl. 4, fig. 4a-b, non Murex hexagonus oxytatus Smith, 1938 .

Murexsul oxytatus sensu Merle & Houart, 2003 : fig. 4F, non Murex hexagonus oxytatus Smith, 1938 ; sensu Houart 2006: 52, figs 19, 21-22, non Murex hexagonus oxytatus Smith, 1938 .

TYPE LOCALITY. — « Antilles ». The locality Antilles is given on the label of the type material (Y. Finet MHNG, written communication ).

TYPE MATERIAL. — In the margin of the exemplar of Animaux sans Vertèbres ( Lamarck 1822) belonging to Lamarck, his daughter indicated the number of specimens stored in his collection. For Murex hexagonus Lamarck, 1822 , she wrote four specimens and now only two are retrieved. They represent two syntypes and have the following register number: MHNG INVE 51843 (corresponding to the old numbers MHNG 1099/ 41/1, H: 43.4 mm and MHNG 1099/41/2, H: 34.6 mm) MHNG 1099/ 41/1, H: 43.4 mm and MHNG 1099/41/2, H: 34.6 mm). In order to avoid confusion with other species, a lectotype of Murex hexagonus Lamarck, 1816 is hereby designated from the syntype MHNG 1099/ 41/1 . Thus, the syntype MHNG 1099/41/2 becomes a paralectotype.

OTHER MATERIAL EXAMINED. — 1 spm, coll. BG, Palm Beach , Florida, USA, H: 33.3 mm ; 1 spm, coll. BG, Florida, at 18 m deep; H: 39.9 mm ; 1 spm, coll. BG, Bimini, Bahamas, at 90 m deep, H: 19 mm ; 1 spm, coll. BG, Cuba, H: 41 mm ; 2 spm, coll. BG, Dominican Republic, H: 25.6 and 16.6 mm ; 2 spm, coll. BG, Anse Colombier, St Barthelemy Island , H: 26 and 2.8 mm ; 2 spm, coll. DL, Anse Colombier, St Barthelemy Island , H: 31.5 and 34 mm ; 1 spm, coll. DL, St Barthelemy Island ., in 30-40 m deep, H: 39.5 mm ; 1 spm, coll. JP, Le Remorqueur , Saint Martin Island, at 14 m deep, H: 14.7 mm ; 1 spm, coll. JP, Rocher Créole , Saint Martin Island, at 6 m deep, H: 30.4 mm .

GEOGRAPHIC RANGE. — Bahamas, Florida, Cuba, Puerto Rico, Turks and Caicos, Lesser Antilles, Dominican Republic, Saint Barthélemy and Saint Martin, from 3 to 90 m deep. See Fig. 8 for a comparison with the geographic range of M. oxytatus ( Smith, 1938) .

DESCRIPTION OF THE LECTOTYPE

Protoconch unknown. Teleoconch biconic, H 43.4 mm, D 24 mm. Spire acute of seven carinate whorls. Last whorl of 70% of the total height. Apical angle of 42°. Spiral sculpture consisting in marked primary and secondary cords. First whorl:appearance of IP and P1. Second whorl to penultimate whorl: IP, P1, P2 and P3. Last whorl: sutural ramp, adis, IP and abis; convex part of the whorl, P1, P3, P4 and P5 well developed and P2 atrophied; siphonal canal, P6 atrophied, ADP, MP and ABP well developed. Secondary cords s1to s5(on convex part of the whorl). Longest shoulder spines (P1) distally acute. Axial sculpture with six varices. Aperture oval, Columellar lip smooth, slightly erected anteriorly and lacking columellar fold. Outer lip crenulated, with denticles ID simple, D1 + D2 (fused denticles), D3, D4 and D5 simple. Siphonal canal open, of 29% of the total length, dorsally and left turned. Microsculpture with growing lamellae. Shell cream, varices and spines tan, primary cords P1, P3, P4 and P5 white. Aperture white. Operculum and radula unknown.

ADDITIONAL DESCRIPTION BASED ON OTHER MATERIAL

Protoconch 1.5 whorls. H: between 18.9 mm and 43.4 mm for adult specimens. In large specimens: D1 and D2 not fused, D3 and D4 splitted. Microsculpture squamous or cancellate in juveniles. Sometimes, a darker spiral band between P3 and P4. Operculum with apical nucleus.

REMARKS

Lamarck (1816) figured Murex hexagonus Lamarck, 1816 among shells coming from the Antilles and gave a description in 1822. Unfortunately, this name had previously been proposed by Gmelin (1791) and is usually unaccepted, because it is considered to be a junior primary homonym. However, the article 23.9.5 of the ICZN (1999) stipulates that: “When an author discovers that a species-group name in use is a junior primary homonym [Art. 53.3] of another species-group name also in use, but the names apply to taxa not considered congeneric after 1899, the author must not automatically replace the junior homonym” – the case should be referred to the Commission for a ruling under the plenary power and meanwhile prevailing usage of both names is to be maintained.” In respect to this article, these two names are not considered congeneric after 1899 and the prevailing usage is maintained for Murex hexagonus Lamarck, 1816 and Cerithium hexagonum ( Gmelin, 1791) . Murex hexagonus Gmelin, 1791 , from the Middle Eocene of Europe, has been transferred in genus Cerithium ( Bruguière 1792) . Murex hexagonus Gmelin, 1791 is a junior synonym of Murex angulatus Solander in Brander 1766 and belongs to the genus Pyrazopsis Akopjan, 1972 ( Harzhauser et al. 2013). In conclusion, the name Murex hexagonus Lamarck, 1816 should be rehabilitated.

Later, Smith (1938) described a subspecies Murex hexagonus oxytatus from a Plio-Pleistocene fossil (Caloosahatchee Formation, Florida, USA) and since Abbott (1958), M. oxytatus is usually used for Recent material ( Abbott 1974, Fair 1976, Radwin & d’Attilio 1976, Abbott & Dance1982, Vokes 1994, Houart 2006 see above the synonymic list). However, the case of M. hexagonus Lamarck, 1816 was not reconsidered and Vokes (1994) discussing M. zylmanae (Petuch, 1993) suggested that the figure of Murex hexagonus Lamarck, 1816 displays more similarities with M. zylmanae than with M. oxytatus . Thus, the question of the identity of M. hexagonus Lamarck, 1816 was open. The study of numerous specimens of Murexsul collected in the Caribbean area allows to identify seven local species: Murexsul oxytatus ( Smith, 1938) , M. huberti ( Radwin & D’Attilio, 1976) , M. zylmanae and M . chesleri Houart, 2006, M. sunderlandi (Petuch, 1987) , M. warreni (Petuch, 1993) , M. jahami Merle & Garrigues, 2011 and to distinguish an eighth species. Thanks to the collaboration of Y. Finet (MHNG), we received photos of the two syntypes of Murex hexagonus . These photos correspond to the species that we identified as the eighth species.

COMPARISON (SEE ALSO TABLE 3 )

Murexsul oxytatus ( Fig. 7G, H ) is distinguished from M. hexagonus by columellar folds and by a shorter siphonal canal. In M. oxytatus , the length of siphonal canal is 24% of the total length of the teleoconch (average on 11 spm), instead of 28% for M. hexagonus (average on 14 spm), see also Fig. 9 . In addition, the cord spines P1 of M. hexagonus are longer than those of M. oxytatus . Murexsul zylmanae ( Fig.7I ) differs from M.hexagonus by hypertrophied cord spines P1, P3 and P5, an atrophied P4, a longer siphonal canal and a more acute spire. Murexsul huberti ( Fig. 7J ) has a lower spire than M. hexagonus with an apical angle of 54° instead of 44°. It displays seven varices on last whorl instead six. The protoconch is also shorter with 1.25 whorls instead 1.5 whorls. Murexsul chesleri ( Fig. 7K ) exhibits a shorter siphonal canal, a broader infrasutural ramp. In M. chesleri , the cord spine P3 is longer than the P1 cord spine whereas in M. hexagonus , the P1 cord spine is longer than the P3 cord spine. Murexsul sunderlandi (Petuch, 1987) has a more globose shell with a lower spire and a peculiar red colour with white spiral bands. In comparison with M. warreni (Petuch, 1993) , M. hexagonus displays a narrower shape, a higher spire and a longer siphonal canal. Murexsul warreni bears a white color white with black spots. Murexsul jahami Merle & Garrigues, 2011 , differs from M. hexagonus by an inflated last whorl, a P5 less developed, a more expanded columellar lip and a very scabrous surface.

Figures

FIG. 7. — A-F, Murexsul hexagonus (Lamarck, 1816): A, B, ventral and dorsal views, lectotype (MHNG 1099/41/1); C, ventral view, paralectotype (MHNG 1099/41/2); D, ventral view, coll. BG, Cuba; E, ventral view, coll. DL, Saint-Barthélemy Island, 30-40 m deep; F, ventral view, coll. BG, Bimini, Bahama, 90 m deep. G, H, M. oxytatus (Smith, 1938): G, ventral view, paratype UF no. 5946, Caloosahatchee Formation, Plio-Pleistocene, Hendry County, Florida, photo courtesy of John Slapcinsky (UF); H, ventral view, coll. BG, Rosalind Bank, Honduras, on coral reef at 20 m deep. I, ventral view, M. zylmanae (Petuch, 1993), holotype CMNH no. 47379, Great Isaacs Cay,Bahamas,photo courtesy of M. Paustian (CMNH).J, ventral view,M. huberti (Radwin & D’Attilio, 1976),holotype SDNHM, no. 63078, west side of Grenada, West Indies, at 4.5 m deep, photo courtesy of Carole Hertz, Jim Berrian, Michael Wall and Paul Tuskes (SDNHM). K, ventral view,M. chesleri Houart, 2006, paratype MNHN no. 7008, Roatan Island,Honduras, on dead coral at 2 m deep.L, ventral view,M. sunderlandi (Petuch, 1987),holotype, USNM 859848,Cay Sal,Cay Sal Bank,Bahamas,under coral rubble at 10 m deep, photo courtesy of E. Strong (USNM). M, ventral view, M. warreni (Petuch,1993),holotype CMNH, Montego Bay,Jamaica, Greater Antilles, 20-30 m deep, photo courtesy of M. Paustan (CMNH). N, ventral view, M. jahami Merle & Garrigues, 2011, holotype MNHN.IM.24630, Peninsula Caravelle, Eastern Martinique. Scale bars: 10 mm.

FIG. 12. — Morphology of spiral cords and denticles: A, Pygmaepterys pointieri n. sp., holotype MNHN-IM-2013-8488, Gosier Island, at 6 m deep; B, P. karukerensis n. sp., holotype MNHN IM-2000-27730, Pigeon Island, at 50 m deep; C, Lindapterys domlamyi n. sp., holotype MNHN IM-2000-27732; D, Muricopsis guadalupensis n. sp., holotype MNHN IM-2000-27731, Malendure, Guadeloupe, at 10 m deep; E, Murexsul hexagonus (Lamarck, 1816), lectotype (MHNG 1099/41/1). Abbreviations: see Material and methods. Scale bars: 5 mm.

FIG. 8. — Map showing the geographic range of Murexsul hexagonus (Lamarck,1816) and Murexsul oxytatus (Smith, 1938).Symbols: Â, M. hexagonus; ™, M. oxytatus.

FIG. 9. — Scatterplot showing the relationship between the length of the siphonal canal (×2) and the total shell length in Murexul hexagonus and in Murexsul oxytatus (Smith,1938).Symbols:¿, Murexsul oxytatus; ¢, Murexsul hexagonus Lamarck,1816;—, Linéaire (Murexsul oxytatus; --, Linéraire (Murexsul hexagonus).