Cylichnoides densistriatus ( Leche, 1878 )

Chaban, E. M., 2016, Opisthobranch molluscs of « Cylichna occulta group » (Gastropoda: Opisthobranchia: Cylichnidae) from the Chukchi Sea and adjacent waters, The Bulletin of the Russian Far East Malacological Society 20, pp. 5-26 : 13-14

publication ID

https://doi.org/ 10.5281/zenodo.11087801

DOI

https://doi.org/10.5281/zenodo.11620770

persistent identifier

https://treatment.plazi.org/id/C85AF226-FF87-FFFA-BCD8-FCC6FD521D45

treatment provided by

Felipe

scientific name

Cylichnoides densistriatus ( Leche, 1878 )
status

 

Cylichnoides densistriatus ( Leche, 1878) View in CoL

Figs 3B View Fig ; 6I–L View Fig ; 7K–L View Fig

Utriculopsis densi-striata Leche, 1878, p. 74 View in CoL –75, Taf. 1, fig. 20.

Utriculopsis densistriata Leche, 1878 View in CoL : Herzenstein, 1885, p. 707.

Diaphana densistriata ( Leche, 1878) : Aurivillius, 1887, p. 371.

Cylichna densistriata ( Leche, 1878) : Knipowitsch, 1896, p. 300.

Cylichna occulta densistriata ( Leche, 1878) : Lemche, 1948, p. 79, figs 40a, 40b (paratype); Lemche, 1956, p. 236–239, pl. 1, figs 9, 10, 11; pl. 4, figs 42, 44; pl. 6, fig. 63; pl. 7, figs 82, 84; pl. 42, fig. 348.

Cylichnoides densistriata ( Leche, 1878) View in CoL : Chaban, 2001, p. 108; Chaban, 2004, p. 83 –84, fig. 5C, D; Chaban, 2010, p. 76, fig. 6.5.

Type locality. Kara Sea, 63º05′ N, 73º45′ E, 9–70 fms.

Type s p e c i m e n s. SMNH [ Lemche, 1956, p. 236].

Material studied. New Siberian Islands : Russian polar expedition, R / V «Zarya», 1903, Kotelny Il., coll. A. V. Kolchak, det. N. Knipowitsch – 5 specimens ; East-Siberian Sea : R / V «Ivan Kireev», 2004, station 87, 69º31′17′′ N, 170º25′97′′ E, 11 m depth – 1 specimen; station 90, 70º02′81′′ N, 170º04′62′′ E, 18 m depth – 2 specimens; station 108, 70.275º N, 168.376º E, 27 m depth – 1 specimen; station 110, 70.835º N, 162.877º E – 2 specimens; Laptev Sea : 24.08.1973, Kondrat’evsky Isl., 7 m depth, coll., det. by A.N. Golikov – 2 specimens ; R / V «Ivan Kireev», 1993, station 31/53, 75.0000º N, 129.5730º E, 40 m depth, mud – 3 specimens GoogleMaps ; R / V «Yakov Smirnitstkiy», 1995, station 60, 74.5401º N, 135.0002º E, 23 m depth, clay – 2 specimens GoogleMaps ; station 62, 72.5501º N, 134.0003º E, 17 m depth, clay – 1 specimens.

D e s c r i p t i o n. Shell ( Fig. 6I–L View Fig ) very thick and strong, almost globose, up to 6 mm, very wide at the top, apex umbilicated, columellar margin short, straight, often wide, almost parallel to axis of shell. Spiral sculpture ( Fig. 7L View Fig ) consists of alternating narrow deep wavy grooves and ribs.

Anatomy. Studied specimens 5–5.5 mm height are adult, their narrow twisted prostate joined with a lateral side of the penial sac ( Fig. 3B View Fig ). Radula is 2:1:1:1;2 ( Fig. 7K View Fig ), bilobate rachidian teeth with straight denticles.

D i s t r i b u t i o n. White, Kara, Laptev and East-Siberian seas from 5 to 170 m [ Leche, 1878; Herzenstein, 1885; Aurivillius, 1887; Knipowitsch, 1896; Chaban, 2001, 2004, 2010].

N o t e s. The type specimens of C. densistriatus have not been studied here but the specimens here described belong to this amazing species without doubt. The species is easily defined due to their almost globose thick shell and hard spiral sculpture, and according to figures given by Leche [1878] and Lemche [1956]. C. validus differs from C. densistriatus in shell shape, sculpture and columellar margin. C. densistriatus has a very thick shell with hard spiral sculpture. C. occulta from Jørgen Brønlund Fjord (North Greenland) was regarded by Schiøtte [1989, fig. 11C] as identical to C. densistriatus due to the shell shape, but it does not have the appropriate spiral sculpture and is determined not to be C. densistriatus . Radula of the type specimen was studied by Lemche and he noted that the denticulation on the rachidian tooth is continuous over the median incision [ Lemche, 1956, p. 238]. This characteristic and the shell morphology distinguish C. densistriatus from other species of the genus. The species is not found to the east of the East-Siberian Sea.

SMNH

Department of Paleozoology, Swedish Museum of Natural History

R

Departamento de Geologia, Universidad de Chile

V

Royal British Columbia Museum - Herbarium

Kingdom

Animalia

Phylum

Mollusca

Class

Gastropoda

Order

Cephalaspidea

Family

Eoscaphandridae

Genus

Cylichnoides

Loc

Cylichnoides densistriatus ( Leche, 1878 )

Chaban, E. M. 2016
2016
Loc

Cylichnoides densistriata ( Leche, 1878 )

Chaban I. 2010: 76
Chaban I. 2004: 83
Chaban E. M. 2001: 108
2001
Loc

Diaphana densistriata ( Leche, 1878 )

Aurivillius C. W. S. 1887: 371
1887
Loc

Utriculopsis densistriata

Herzenstein S. 1885: 707
1885
Loc

Utriculopsis densi-striata

Leche W. 1878: 74
1878
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