Cirsotrema matugisiense (Ozaki, 1958)

Sirenko, Boris I. & Drobyazin, Evgeny N., 2020, New finding of the epitoniid Cirsotrema matugisiense (Ozaki, 1958) (Mollusca: Gastropoda) in the Sea of Japan, The Bulletin of the Russian Far East Malacological Society 24 (1 / 2), pp. 61-66 : 62-66

publication ID

https://doi.org/ 10.24866/1560-8425/2020-24/61-66

DOI

https://doi.org/10.5281/zenodo.11243516

persistent identifier

https://treatment.plazi.org/id/124A9556-FFEC-FFDB-FE69-FA7CD04EFDD7

treatment provided by

Felipe

scientific name

Cirsotrema matugisiense (Ozaki, 1958)
status

 

Cirsotrema matugisiense (Ozaki, 1958) View in CoL

Figs. 1 View Fig , 2B–F View Fig

Epitonium (Boreoscala) matugisiensis Ozaki, 1958, p. 142 View in CoL , pl. 15, fig. 25 (fossil); Brown, Neville,

2015, p. 102 (fossil and Recent).

Epitonium (Boreoscala) yokozunai Ozaki, 1958, p. 143 View in CoL , pl. 15, fig. 26 (fide Nakayama [2003]) (fossil).

Cirsotrema matugisiense (Ozaki, 1958) View in CoL : Nakayama, 2003, p. 29, pl. 4, figs. 23–27 (fossil and Recent); Tsushida, Hasegawa, 2017, p. 894, pl. 183, fig. 7 (fossil and Recent).

Ty p e m a t e r i a l. The holotype ( NSMT 4498 View Materials ) .

Ty p e l o c a l i t y. Cliff, 500 m south of Matugisi Railway Station, Tyosi City, Iioka Formation, Neogene.

M a t e r i a l e x a m i n e d. The Sea of Japan, near western Sakhalin, 47°16.4′– 47°15.9′ N, 141°47.3′– 141°47.0′ E, depth 386–388 m, mud, R / V Bukhoro, research trawl, 2 specimens ( ZISP 62489 View Materials ); 1 specimen ( FEFU XII 53121 /Ga-10171), 04.07.2018, coll. E.N. Drobyazin GoogleMaps ; 47°16.5′– 47°15.9′ N, 141°45.2′– 141°44.6′ E, depth 521 m, mud, R / V Bukhoro, research trawl, 1 specimen, 28.05.07.2015, coll. I. Kornejchuk. GoogleMaps

D i s t r i b u t i o n. Japan: Boso Peninsula (fossil) [ Nakayama, 2003; Tsuchida, Hasegawa, 2017], off Kunashir Island, Hokkaido, Japan [ Nakayama, 2003] and the Sea of Japan, near western Sakhalin (this study). Nakayama [2003] was the first to report the discovery of this species in the Recent fauna near Kunashir Id. and Hokkaido. Unfortunately he did not give more detailed information about locality and depths. Specimens collected from western Sakhalin significantly advance the boundaries of the area of this species to the north and are the first find of the species off the coast of Russia. Reports of the distribution of this species off Greenland and in the Arctic seas [ Tsuchida, 2000], appear to be associated with incorrect identifications. Kazunori Hasegawa (in e-mail message) informed that he has seen specimens of this species only from the north-western Pacific (eastern Hokkaido and northwards), Okhotsk Sea and northern Sea of Japan.

Due to some differences between western Sakhalin specimens and fossil type and other similar specimens, we found it useful to give a brief description and distinctive diagnosis .

D e s c r i p t i o n. Shell big for the genus, height up to 85.4 mm, high, thin but rather solid, grayish white. Protoconch damaged, teleoconch consist of 7 convex whorls separated by distinct narrow sutures. Axial sculpture of teleoconch whorls consisting of numerous, low ribs of different thickness especially on the last whorl, where there are 36 axial ribs. Spiral ribs rather low, flattened, wide, 6 spiral ribs on whole surface of each whorl excluding base. Axial and spiral ribs presenting weakly cancellated appearance. Umbilicus narrow, fissure-like. Aperture round, the outer edge of the aperture is thickened by a wide axial rib, columellar lip narrow, smooth, slightly erect, the inner surface of the aperture purple. Operculum brownish black, paucispiral, nucleus of operculum shifted to the lower left edge.

There is no information about the radula due to the lack of soft parts of the body.

R e m a r k s. The protoconchs of all studied specimens were destroyed, so the real height of the shell is a few millimeters more (see Table). Nakayama [2003] believes that the holotypes of Epitonium (Boreoscala) matugisiense Ozuka, 1958 ( Fig. 2F View Fig ) and E. (B). yokozunai Ozuki, 1958 ( Fig. 2B, E View Fig ) are two parts of the same shell, so he composed the characters.According to the new diagnosis, the holotype of C. matugisiense has 26 axial ribs and 9 spiral ribs, which is at odds with the number of ribs in western Sakhalin specimens. In addition, the last specimens have a slit-like umbilicus. Kasunori Hasegawa (in e-mail message) and we believe that this is the result of intraspecific variability.

C. matugisiense differs from the other species of the family Epitoniidae View in CoL , having few low flattened, wide spiral ribs throughout the whole surface of each whorl, excluding the base. Most similar to C. matugisiense is Amaea iwaotakii Azuma, 1961 View in CoL ( Fig. 2A View Fig ). A. iwaotakii View in CoL differs from C. matugisiense in having the whorls with many distinct minute spiral striae except on the upper third of each whorl [ Azuma, 1961] (vs. a few low flattened, wide spiral ribs throughout the whole surface of each whorl excluding the base in C. matugisiense ); all axial ribs are rather similar in size (vs. the axial ribs of different thickness, especially on the last whorl, in C. matugisiense ).

R

Departamento de Geologia, Universidad de Chile

V

Royal British Columbia Museum - Herbarium

Kingdom

Animalia

Phylum

Mollusca

Class

Gastropoda

Order

Architaenioglossa

Family

Epitoniidae

Genus

Cirsotrema

Loc

Cirsotrema matugisiense (Ozaki, 1958)

Sirenko, Boris I. & Drobyazin, Evgeny N. 2020
2020
Loc

Cirsotrema matugisiense (Ozaki, 1958)

Nakayama T. 2003: 29
2003
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