Mangelia vanaartseni, Öztürk, 2021

Öztürk, Bilal, 2021, Mangelia (Gastropoda, Conoidea) species of the Turkish coasts with description of Mangelia vanaartseni sp. nov., Zootaxa 4933 (2), pp. 241-262 : 257-259

Mangelia vanaartseni sp. nov.

( Fig 19 )

Material examined. Four specimens were sampled from the Levantine and Aegean coasts between 2015 and 2019. The holotype and paratypes are deposited in the Museum of the Faculty of Fisheries at Ege University (Izmir, Turkey) .

Holotype. ( Figure 19 A, B, C ). Taşucu, Levantine Sea, 36.23355° N- 33.89467° E, 25 m, total height 4.4 mm, width 1.3 mm ( ESFM-GAS/2019-04 ).

Paratype A. ( Figure 19 D, E ). Akköy, Aegean Sea , 37.45183°N- 27.12383°E, 66 m, total height 3.4, width 1.5 mm ( ESFM-GAS/2015-23 ) .

Paratype B. ( Figure 19 , F, G, L). Marmaris Bay, Aegean Sea , 36.813560° N- 28.495550° E, 26 m, total height 3.7 and 3.1 mm, and width 1.6 and 1.3 mm, respectively ( ESFM-GAS/2017-79 ) .

Type locality. Known from the localities from where the examined material was sampled.

Etymology. The species was named after the late John J. van Aartsen for his contributions in the field of the malacology.

Description. Shell biconic, of small size, height 3.1–4.4 mm, width 1.3–1.6 mm. Protoconch paucispiral of about 1.3 rounded, transparent and glossy whorls. On the last whorl with some oblique axial riblets before the boundary with the teleoconch. Teleoconch of 3.6–4 whorls, shouldered adapically, and with evident subsutural ramp below the suture. On the whorls, a sculpture of orthocline axial ribs and spiral cords of unequal thickness. Axial ribs (on the body whorl 8–9 ribs) a bit thinner and curving regularly towards the suture and continue nearly to the base. The interspaces between the axial ribs twice as wide as ribs. Spiral sculpture consists of dense and thin spirals alternating with intermittently thicker ones ( Figure 19 , M). On subsutural ramp only thin spirals of equal thickness. Aperture long, narrow and about 2/3 height of the body whorl. Columella smooth, outer lip with labial varix. Posterior sinus evident. Siphonal canal short and wide. On the siphonal fasciole relatively thicker cords. Color range of the shell from whitish to light brown, sometimes with fine lines in lighter color. Protoconch glossy white or light brown. Sometimes there is a brown spot on the inner part of outer lip.

Distribution. It is known from the localities in the Levantine and Aegean Seas mentioned above where the examined materials were sampled.

Remarks: Based on its conchological characteristics (shell shape and size, profile, spiral cords of unequal size, number of axial ribs on the body whorl), Mangelia vanaartseni appears to be a sister (sibling) species of Mangelia unifasciata ( Figure 19 , H–K), from which it differs by its paucispiral protoconch. It may also be confused with Mangelia secreta which has a similar spiral sculpture, but the latter species is different by its light color with rust colored spiral band on the body whorl, and the protoconch with more whorls.

Figures

FIGURE 19. Mangelia vanaartseni sp. nov. (A–F): Holotype (ventral: A, dorsal: B views of the specimen and its protoconch: C), Paratypes A (D, E), Paratype B (F, G and L) and Mangelia unifasciata (H–K) (H, J: general view of two specimens and their protoconchs I and K (H=4.3 mm, Aegean Sea (Ildır Bay), 10 m; J=6.0 mm, Fethiye Bay, 25 m, M: microsculpture).