Paraseraphs placitus Jung, 1974

Caze, Bruno, Merle, Didier, Pacaud, Jean-Michel & Saint Martin, Jean-Paul, 2010, First Systematic Study using the Variability of the Residual Colour Patterns: The Case of the Paleogene Seraphsidae (Mollusca, Gastropoda, Stromboidea), Geodiversitas 32 (3), pp. 417-477 : 456

Paraseraphs placitus Jung, 1974 ( Figs 24 G-M; 28)

Paraseraphs placitus Jung, 1974: 38 , pl. 10, figs 13-18, text-fig. 28.

Terebellum fusiforme – Sowerby 1821: 157, pl. 287. — De Blainville 1828: 276. — Deshayes 1835: 738, pl. 95, figs 30, 31. Non Lamarck, 1802.

Terebellum (s.s.) fusiforme – Glibert 1938: 65, 66, pl. 2, fig.7. — Cossmann 1889: 96 partim. Non Lamarck, 1802.

Terebellum (s.s.) fusiforme postconicum Cossmann, 1904: 44. Non de Gregorio, 1880.

Paraseraphs placitus – Dolin et al. 1980: 28. — Le Renard 1992: 6. — Le Renard & Pacaud 1995: 112. — Pacaud & Le Renard 1995: 162.

TYPE LOCALITY. — Les Garennes, Chaussy (Val d’Oise, France), Lutetian (Middle Eocene).

TYPE MATERIAL. — Holotype ( NMB H14491); paratype ( NMB H10539), Les Garennes, Chaussy ( Val d’Oise , France); paratypes ( UCBL coll. Deshayes), Mouchy-le- Châtel (Oise) and Parnes (Oise), not found.

OTHER MATERIAL EXAMINED. — See Appendix 1.

DESCRIPTION

Shell

Shell up to 30 mm in height and 7 mm in diameter, moderately slender and evolute with distinct suture. Aperture long and narrow. Callus of the inner lip well developed, well delineated, extending to the apex and forming a narrow band parallel to the outer lip ( Fig. 24I ). Basal part of the columella bent backwards. Outer lip, almost straight and slightly opisthocline ( Fig. 24H, M ), not thickened on the basal part of the shell. Adapical part of the outer lip thickened and extending from the adapical end of the aperture, towards the apex ( Fig. 24H ), or bent towards the dorsal side ( Fig. 24M ). Siphonal notch moderately deep. Sculpture with a few oblique grooves near the base of the shell ( Fig. 24K ).

Colour pattern

Paraseraphs placitus has numerous and irregular dots with 2 levels of residual coloration on a lighter background ( Fig. 28 ). The first level consists of triangular spots, darker than the background.Th ese spots, more or less distorted, are orientated towards the growing edge ( Fig. 28C, F, L ). The second level consists of fluorescent spots with fuzzy borders, lighter than the background. These light spots, adjacent to the base of dark spots, are narrow and directed towards the inner lip in ventral view ( Fig. 28C, F, L ). They are variable in size. Th ese two components form the dots. The density of dots is generally low. Also, a peculiar pattern can be distinguished on the adapical part of the outer lip: an oblique succession of darker and lighter “patches” ( Fig. 28B, D, E, M, N ). These “patches” are probably the result of the coalescence of the dark axial segments ( Fig. 28D ).

VARIABILITY

Sometimes the darker spots of the dots are larger near the edge of the outer lip ( Fig. 28B, C, P ) and are coalescent.

Figures

FIG. 24. — Paraseraphs Jung, 1974 shells in normal light: A-F, P. tetanus Jung, 1974; A-C, MNHN A28579 (Faullummel coll.), Saint- Gobain, Aisne, France, Ypresian (Cuisian); A, ventral view; B, labral view; C, dorsal view; D-F, MNHN A28787 (Ferry coll.), Cuise- Lamotte (Butte-des-Usages), Oise, France, Ypresian (Cuisian); D, ventral view; E, labral view; F, dorsal view; G-M, P. placitus Jung, 1974; G-J, MNHN A28786 (Lhomme coll.), Chaussy (Les Garennes),Val d’Oise, France, Lutetian; G, ventral view; H, labral view; I, detailed view of the apical part; J, dorsal view; K, MNHN A28962 (detailed view of the basal part) (leg. Pacaud), Fercourt, Oise, France, Lutetian; L, M, MNHN A28774 (Lhomme coll.), Chaussy (Les Garennes), Lutetian; L, dorsal view; M, labral view. Scale bars: A-H, J, L, M, 10 mm; I, 5 mm; K, 2 mm. Photographs by C. Lemzaouda (MNHN).

FIG. 28. — Paraseraphs placitus Jung, 1974 under UV light: A-G, MNHN A28961 (leg. Pacaud), Fercourt, Oise, France, Lutetian; A, ventral view; B, labral view; C, detailed view of the outer lip; D, detailed view of the adapical part of the outer lip; E, detailed view of the dots; F, dorsal view; G, detailed view of the subsutural part; H, I, MNHN A28960 (leg. Pacaud), Parnes, Oise, France, Lutetian; H, dorsal view; I, abapertural view; J-L, MNHN A28963 (Ballot coll.), Grignon, Yvelines, France, Lutetian; J, ventral view; K, dorsal view;L, detailed view of the dots; M, N, MNHN A28966 (Boule coll.), Chaussy (Les Garennes),Val d’Oise,France, Lutetian;M, detailed view of the apical part; N, dorsal view; O, P, MNHN A28964 (Ballot coll.), Grignon, Lutetian; O, dorsal view; P, labral view. Scale bars: A, B, F, H-K, N-P, 10 mm; C-E, G, L, M, 2 mm. Photographs by C. Lemzaouda (MNHN).