Scissurella azorensis , Nolt, Jaya M., 2008

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: 54-56

publication ID

http://doi.org/ 10.5281/zenodo.180366

persistent identifier

http://treatment.plazi.org/id/03C287E4-B908-1E33-2FFA-FB2BFA97EFB4

treatment provided by

Plazi

scientific name

Scissurella azorensis
status

new species

Scissurella azorensis  new species

( Fig. 1View FIGURE 1, Fig. 2View FIGURE 2 A)

Holotype. MNHNAbout MNHN Moll 9640, gold coated.

Paratypes. 2 MNHNAbout MNHN Moll 9641, from type locality. 1 MCZAbout MCZ 356976, Pedra Furada, Baia do Alcaide, Silveira, Terceira Island, Azores 38 ° 39 ’ N, 27 ° 14 ’ W, all gold coated.

Type locality. Santa Maria Island, off Ponta do Marvão, Azores. 0–1 m, in rocks. June 1990. Leg. S. and C. Gofas. 36 ° 56 ’N, 25 °08’W.

Etymology. Named for the provenance from the Azores.

Description. Shell small to 0.75 mm, trochoid with flat spire, one fourth wider than high, whitish. Protoconch 120 µm long, 1.16–1.2 whorls, 24–28 strong to irregular axial cords, axials on outer margin of protoconch not extending full width, no apertural varix, apertural margin rounded. Teleoconch I slightly greater than one whorl, approximately 18–20 strong axial cords, fine irregular lamellae between axials, no spiral sculpture. Teleoconch II 0.75 whorls, with nine weaker axial cords, fine irregular lamellae, no spiral sculpture. Shoulder angled down from coiling axis with fine irregular lamellae. Base rounded, with 18–25 weak axial cords, fine irregular lamellae between axials. Umbilicus open with marginal carina, weak axial lines on base. Selenizone, slit above periphery, moderately keeled. Aperture subquadratic, edge slightly projecting. Animal unknown.

Distribution. Only known from the type material from the Azores.

Comparisons. The holotype ( Fig. 1View FIGURE 1 A) is a mature Scissurella  spp. and not a juvenile Sinezona  spp. because it shows an open slit with the long angled shoulder and descending last quarter whorl. Compared to the other species of the region, Sci. azorensis  is distinguished by the protoconch sculpture which contains axial cords on the outer margins only, an open umbilicus region, teleoconch I is slightly greater then one whorl and the numerous strong axial cords over the entire shell.

Scissurella lobini ( Burnay & Rolán, 1990)  from the Cape Verde Islands ( Fig. 3View FIGURE 3 A) and Scissurella redferni ( Rolán, 1996)  from the Caribbean ( Fig. 3View FIGURE 3 B) both differ from Sci. azorensis  in that the protoconch has fewer axial cords (24–28 in Sci. azorensis  , 14–18 in Sci. lobini  and Sci. redferni  ), the axials are more uniform in shape and the bases of Sci. redferni  and Sci. lobini  have spiral threads. Scissurella costata d’Orbigny, 1824  from the Mediterranean ( Fig. 3View FIGURE 3 C) has a flattened spire, apertural margin of the protoconch is sinusoid, teleoconch sculpture contains thin irregular axial lines and spiral threads on shoulder and base, and teleoconch II has approximately 1.3 whorls. Since Sinezona  and Scissurella  spp. may be difficult to distinguish in juvenile stages due to the incomplete closure of the slit in the foramen, comparisons are also made with Sinezona  spp. from the Atlantic-Mediterranean region. Sinezona cingulata  ( O.G. Costa, 1861) from the Mediterranean ( Fig. 2View FIGURE 2 B) has a protoconch sculpture with approximately 15 strong axial cords that cover more than half the width. Teleoconch I has fewer then one whorl, with 14 axial cords and the umbilicus is very narrow. Sinezona semicostata Burnay & Rolán, 1990  from the Cape Verde Islands ( Fig. 4View FIGURE 4 A) most closely resembles Sci. azorensis  but has approximately 12 protoconch axial cords over more than half the width and teleoconch I has fewer than one whorl and as a member of Sinezona  , the foramen is closed in mature specimens. Sinezona confusa Rolán & Luque, 1994  from the Caribbean ( Fig. 4View FIGURE 4 B) has protoconch sculpture with approximately 14 axial cords that cover more than half the width, an apertural varix and spiral threads on teleoconch I and II.

MNHN

Museum National d'Histoire Naturelle

MCZ

Museum of Comparative Zoology

Kingdom

Animalia

Phylum

Mollusca

Class

Gastropoda

Family

Scissurellidae

Genus

Scissurella

Loc

Scissurella azorensis

Nolt, Jaya M. 2008

2008
Loc

Scissurella redferni ( Rolán, 1996 )

Rolan 1996

1996
Loc

Sinezona confusa Rolán & Luque, 1994

Rolan & Luque 1994

1994
Loc

Scissurella lobini ( Burnay & Rolán, 1990 )

Burnay & Rolan 1990

1990
Loc

Sinezona semicostata Burnay & Rolán, 1990

Burnay & Rolan 1990

1990
Loc

Scissurella costata d’Orbigny, 1824

d'Orbigny 1824

1824