Buccinum kosyanae, Linnaeus, 1758

Kantor, Yuri I. & Sirenko, Boris I., 2024, New species of Buccinum (Neogastropoda: Buccinidae) from the Kurile Islands, Ruthenica, Russian Malacological Journal 34 (1), pp. 1-5 : 2-4

Buccinum kosyanae sp. nov.

( Figs 1 A-E, 2)

Zoobank registration: urn:lsid:zoobank.org:act:

7C725C7F-D4D9-408E-9A1A-9377DFDEAA7B

Buccinum sp. 3 – Sirenko (ed.), 2013: 160.

Buccinum cf. kobjakovae – Kantor et all., 2022b: Fig. 3G.

Type material. Holotype (sequenced)– Kurile Is., off Simushir I., 46°40.6′N, 151°58.4′E, 436 m, R / V Akademik Oparin, cruise 56, stn 19, MIMB 47413 , 02.07.2019, leg. A. Maiorova; 5 paratypes (not sequenced) – Kurile Is., off Ketoy I., 47°19.4’N, 152°39.0’E, 450 m, small and large pebbles, R / V Odyssey, stn 19, geological dredge, 05.01.1985, leg. A. Alekseev and V. Bizikov, ZIN 63719 .

Genbank acquisition numbers (holotype): cox-1 – OM791448 , 28 S – OM778281 [Kantor et all., 2022b].

Description (holotype) ( Fig. 1 A-A’). Shell small, biconical, with weakly angulated shoulder, and strongly angular at transition to shell base. Shell thin, fragile, with short siphonal canal, yellow-brown, with slightly lighter fasciole. Protoconch and upper teleoconch whorls eroded. Remaining teleoconch whorls 3.5. Suture distinct, lightly adpressed at periphery of previous whorl. Axial sculpture of thin nearly orthocline growth lines. Spiral sculpture distinct, consists of a keel on shoulder, more pronounced keel on transition to shell base and smaller unequal cords covering entire shell surface. Cords distinct on shell base and canal, around 20 on penultimate whorl, 23 between suture and basal keel on last whorl and 30 on shell base and canal. Intervals between cords are narrower than cords.

Aperture large, sub-triangular. Outer lip thin, distinctly convex adapically, forming obtuse angle at transition to shell base and nearly straight abapically. Columella with low fold bordering fasciole, short, nearly straight. Siphonal notch indistinct. Periostracum very thin, smooth, tightly adhering. Operculum large, spanning 2/3 of aperture, thin, yellowish, transparent, oval, with subcentral nucleus.

Dimensions (holotype). Shell length 12.2 mm, last whorl length 9.4 mm, aperture length 7.4 mm, shell width 8.8 mm.

Etymology. The new species is named after our late colleague and friend, Russian malacologist Dr. Alisa Kosyan from A.N. Severtsov Institute of Ecology and Evolution, who published numerous papers on north Pacific Buccinoidea .

Remarks. The shell length attains 19.1 mm ( Fig. 1 D , Table 1 ). Other examined specimens are quite similar to the holotype in shell outline and sculpture pattern. In largest specimen the periostracum is forming low axial lamellae.

The new species has a highly distinctive, nearly biconical shell shape. The presence of a robust keel at transition to the shell base is a feature shared with some Buccinum species, such as B. angulosum Gray, 1839 (differing however in the presence of well-developed axial ribs and much larger shell which can exceed 70 mm – Golikov, 1990). This characteristic is sometimes accomplished by more or less obtusely angular shoulder, as observed in B. kashimanum Okutani, 1964 , B. bicordatum ( Golikov et Sirenko, 1988) , B. kobjakovae Golikov et Sirenko, 1988 (depicted on Fig. 1 F-F’ herein), but the shell never achieves such a distinctly biconical shape.

Kantor et al. (2022b) compared the new species to B. kobjakovae (which is known only from the holotype). Nevertheless the new species can be distinguished by its much less pronounced keel on shoulder and broader shell. It bears a certain resemblance to B. kurilense Golikov et Sirenko, 1988 , which differs in much more slender and notably larger shell (42 mm in the holotype).

Distribution. Presently the species was recorded in a very narrow range – only off Simushir and Ketoy Islands, Kurile Islands, at 436-450 m ( Fig. 2 ).

Presently we found out the case of a primary homonymy among Buccinum species (see below).

Figures

FIG. 1. Buccinum kosyanae sp. nov. (A–E). A–A’. Holotype, MIMB 47413, shell length (SL) 12.2 mm. B–E. Paratypes, off Ketoy Island, ZIN 63719 (B–C – SL 15.2 mm; D – SL 19.1 mm; E – SL 17.8 mm). Buccinum kobjakovae Golikov et Sirenko, 1988 (F-F’), holotype, ZIN 48667/1, eastward from Shikotan, Kurile Islands, 285–287 m, SL 10.1 mm.All shells at the same scale except A’ and F’ (enlarged). РИС.1. Buccinum kosyanae sp. nov. (A–E). A–A’. Голотип, MIMB 47413, высота раковины (SL) 12.2 мм. B–E. Паратипы, о. Кетой, ZIN 63719 (B–C – SL 15.2 mm; D – SL 19.1 mm; E – SL 17.8 mm). Buccinum kobjakovae Golikov et Sirenko, 1988 (F–F’), голотип, ZIN 48667/1, восточнее о.Шикотан, Курильские острова, 285–287 м, SL 10.1 мм.Все раковины, кроме A’ и F’ (увеличены) – в одном масШтабе.

FIG. 2. Distribution of Buccinum kosyanae sp. nov. The insert shows map at larger scale. Circle – type locality, square – local- ity of the paratypes. РИС. 2. Распространение Buccinum kosyanae sp. nov. На вкладке приведена карта в более крупном масШтабе. Кружок – типовое местнонахождение, квадрат – нахождение паратипов.