Sinezona cingulata, Sin.

Nolt, Jaya M., 2008, A new species of Scissurella from the Azores with discussions on Sinezona semicostata Burnay & Rolán, 1990 and Sinezona cingulata (O. G. Costa, 1861) (Gastropoda: Vetigastropoda: Scissurellida, Zootaxa 1678, pp. 51-62: 58-59

publication ID

10.5281/zenodo.180366

persistent identifier

http://treatment.plazi.org/id/03C287E4-B90C-1E3C-2FFA-F917FAE0EF3C

treatment provided by

Plazi

scientific name

Sinezona cingulata, Sin.
status

 

Comparisons of Sinezona cingulata, Sin.  fayalensis, Sin.  depressa  and Sin. crossei 

Sinezona cingulata  is applied to a Mediterranean species with type locality Sardinia Island, Italy. The whereabouts of the holotype is unknown. Burnay & Rolán (1990) argued that Costa’s (1861) description did not match the cited figure (here shown in Fig. 5 AView FIGURE 5. A) and that Thiele (1912: figs. 6, 7; here shown in Fig. 5View FIGURE 5. A B) noted a different figure in Costa referring to Sin. cingulata  . They concluded that Sin. cingulata  is a nomen dubium and should be referred to by the first available name to which it is usually applied, Sin. crossei  (Folin, 1896) with designated neotype ( Burnay & Rolán 1990), type locality São Vincente, Cape Verde Islands. However taking into account the microscope technology of that time, the original description matches the figure; with 11–12 strong axial cords on the teleoconch, open umbilicus and semi oval aperture ( Fig. 5 AView FIGURE 5. A). The shorter teleoconch II and open slit in the original figure are characteristic of a juvenile specimen. That the figure in Thiele (1912) was an error and did not contain the strong axial cords of Costa’s original description has no relevance to the identity of Costa’s species. Costa’s original figure of Sin. cingulata  corresponds with the Mediterranean species to which that name has usually been applied. Sinezona crossei  as its neotype illustrated by Burnay & Rolán (1990: pl. 1, figs 3–5) compared to Sin. cingulata  ( Fig. 2View FIGURE 2 B) from Spain show differences in numbers of axial cords (protoconch 18 vs. 17, teleoconch I 14 vs. 12, teleoconch II 16 vs. 13) and spiral lines (7 vs. 5). These differences in amounts are insignificant and can be accounted for by intraspecific variation.

Three syntypes of Sin. depressa  ( BMNH 1911.17.21– 23, one shown here in Fig. 2View FIGURE 2 C), type locality Madeira, and seven specimens of Sin. fayalensis  ( MNHNAbout MNHN, one is shown in Fig. 4View FIGURE 4 C) from Santa Maria Island, Azores where examined. The neotype of Sin. crossei  could not be located in the MNHNAbout MNHN collections (Geiger pers. obs. 4 / 2005), but was adequately illustrated by Burnay & Rolán (1990: pl. 1, figs 3–5). One type specimen of Sin. fayalensis  is in Koninklijk Belgisch Instituut voor Natuurwetenschappen in Brussels (T. Backeljau pers. comm. 10 / 2006), but was not available for examination, hence near topotypical specimens were used in this study. Specimens of Sin. fayalensis  from the Azores tended to display fewer axial ribs and have a smoother sculpture than specimens from the Mediterranean. One syntype of Sin. depressa  was smoother due to erosion. Comparisons of these species with Sin. cingulata  are given in Table 2.

Sculpture and shape are the same. All the specimens have no apertural varix and an open umbilicus. The nominal taxa differ in the number of axial cords (protoconch 16–17 and teleoconch I 12–17) and axial lines (teleoconch II 15–16 and base 12–16). These differences are not sufficient to justify recognition as separate species and can be accounted for by intraspecific variations. A radula of Sin. cingulata  from Spain in Figure 6View FIGURE 6 shows features typically seen in members of Scissurellidae  s.s., including serrated rachidian, with 5 serrated laterals, lateral 5 enlarged and serrated marginals ( Geiger 2003). In Figure 6View FIGURE 6 B the rachidian is triangular with 5 denticles the central on being the largest. The first three laterals have three denticles on the outer margin, the innermost is largest. The fourth lateral tooth is hook shaped. The fifth is broad with about 10 denticles.

TABLE 2. Comparisons of Sin. cingulata, Sin. fayalensis and Sin. depressa.

Species Shell Shape Protoconch Teleoconch I Teleoconch II Base
Sinezona cingulata  Spain (Fig. 3A) trochid, slightly depressed 1.5 whorls, 17 strong axial cords approx. 1 whorl, 12 strong axial cords 0.25 whorls, 16 axial lines, 5 weak spiral lines, irregular lamellae 16 axial lines
Sinezona  fayalen- sis topotypical, Azores (Fig. 3D) trochid, slightly depressed 1.5 whorls, 16 strong axial cords 1 whorl, 14 strong axial cords 0.25 whorls, 15 axial lines, 8 weak spiral lines, irregular lamellae 14 axial lines
Sinezona depressa  syntype, Azores (Fig. 2D) trochid, slightly depressed 1.5 whorls, 16 strong axial cords approx. 1 whorl, 17 strong axial cords 0.25 whorls, 16 axial lines, 4 weak spiral lines, irregular lamellae 12 axial lines
MNHN

Museum National d'Histoire Naturelle

Kingdom

Animalia

Phylum

Mollusca

Class

Gastropoda

Family

Scissurellidae

Genus

Sinezona

Loc

Sinezona cingulata, Sin.

Nolt, Jaya M. 2008

2008
Loc

crossei

Folin 1896

1896