Seraphs peterjungi, Caze & Merle & Pacaud & Saint Martin, 2010

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 : 445-446

publication ID	https://doi.org/ 10.5252/g2010n3a4
persistent identifier	https://treatment.plazi.org/id/03A69848-FF8B-1E42-FF1E-FF2AFE02FB9E
treatment provided by	Marcus
scientific name	Seraphs peterjungi
status	sp. nov.

Treatment

Seraphs peterjungi n. sp. ( Figs 15 View FIG J-N; 19)

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

TYPE MATERIAL. — Holotype: MNHN A28578 View Materials , leg. Pacaud.

Paratypes: Chaussy (Les Garennes), Val d’Oise, 2 ex., MNHN A27613 (1965-11 coll.) ; 1 ex., MNHN A28506 View Materials (Morlet coll.) ; 1 ex., MNHN A28931 (leg. Pacaud) ; 1 ex., MNHN A27273 View Materials (leg. Pacaud) ; 1 ex. MNHN A28537 View Materials (Faullummel coll.) ; 1 ex., MNHN A28538 View Materials (Faullummel coll.) ; 1 ex., MNHN A27550 View Materials (Schtrock coll.) ; 1 ex., MNHN A28550 View Materials (leg. Pacaud) ; 1 ex., MNHN A28559 View Materials (Ledon coll.) ;

Beynes, Yvelines, 1 ex., MNHN A28789 View Materials ;

Fercourt, Oise, 5 ex., MNHN A27634 (leg. Pacaud) ; Grignon, Yvelines, 1 ex., MNHN A27632 View Materials (ex Galerie de Zoologie coll.) ; 1 ex., MNHN A28512 View Materials (leg. Caze) ; 1 ex., MNHN A28530 View Materials (Ballot coll.) ;

Parnes, Oise, 1 ex., MNHN A11186 (d’Orbigny coll.) ; 1 ex., MNHN A28511 View Materials (Roissy coll.) ;

Parnes (Grande Cronière), Oise, 1 ex., MNHN A28521 View Materials (leg. Pacaud) ;

Saulx-Marchaix, Yvelines, 1 ex., MNHN A28520 View Materials (1965- 11 coll.).

ETYMOLOGY. — Dedicated to Peter Jung for his work on the Seraphsidae .

DESCRIPTION OF THE HOLOTYPE

Shell 23 mm in height and 7 mm in diameter, slender with acute apical part. Aperture long and narrow. Callus of the inner lip well developed and delineated, continuing adapically on the spire and forming a narrow band parallel to the outer lip. Columella bent backwards near the base ( Fig. 15K View FIG ). Outer lip slightly thickened and, in labral view, sinuous near the adapical end of the aperture. Outer lip extending to the apex and continuing on the opposite side for a short distance ( Fig. 15K, L, N View FIG ). Siphonal notch moderately deep on the dorsal side of the shell. Surface sculpture of narrow oblique grooves near the base ( Fig. 15M View FIG ).

COLOUR PATTERN DESCRIPTION

The colour pattern shows two different and superimposed levels of residual pigmentation: a dark one and a white and fluorescent one. The background displays an intermediate colour between these two levels. Th e darker elements correspond to several thick spiral rows of patches. Th e lighter fluorescent elements, overlaid on the darker, consist of narrow spiral lines. Th e morphology of the dark elements is similar to the pattern of S. chilophorus : several spiral rows of dark triangles of which the apex is directed towards the outer lip. Th eir width, depending on the size of the patches, is variable ( Fig. 19A, B View FIG ). In addition, some tiny and isolated triangles, orientated towards the outer lip, are visible between the rows ( Fig. 19G, H View FIG ). Th eir size, distribution and shape are heterogenous and irregular ( Fig. 19G, H View FIG ). On the apical part of the shell, the elements are more dense and coalescent, tending to be shapeless.

VARIABILITY

The variability is only observable on the darker elements of the residual pattern. Th e rows can be more or less distant, from widely spaced to contiguous ( Fig. 19A, E, F View FIG ). Dark patches can show considerable shape variation from triangular to completely distorted ( Fig. 19E, F View FIG ). Th ey can be well separated or connected. The fluorescent elements, narrow spiral lines, do not show perceptible variation except in their number: between 16 and 20. SHELL AND COLOUR PATTERN COMPARISONS

The shell of Seraphs peterjungi n. sp. is indistinguishable from that of Seraphs chilophorus . Accordingly, for shell comparison with the other species, see S. chilophorus .

The dark underlying elements of S. peterjungi n. sp. resemble the colour pattern of S. chilophorus , but it appears to be less variable. Seraphs chilophorus never has fluorescent narrow lines.

DISCUSSION

The comparisons between S. peterjungi n. sp. and S. chilophorus are respectively based on 24 specimens and 163 specimens ( Table 1). Using the shell shape, no distinction can be made between the two populations. Using the residual pattern, we can observe a strong similarity in the dark component, suggesting a close relationship. However, S. peterjungi n. sp. shows an additional element with some light and fluorescent spiral lines ( Fig. 19 View FIG ), lacking in all examined S. chilophorus ( Fig. 16 View FIG ) and suggesting a morphological discontinuity. Considering the number of specimens studied and the lack of intermediaries between the two colour patterns, we cannot regard both populations as a single species. In this case, the residual pattern does seem to be a unique discriminating criterion enabling the differentiation of fossil species.