Viriola, Jousseaume, 1884

Viriola View in CoL namyitensis n. sp.

( Figs 2 D–F View FIG , 5 View FIG ; Table 1)

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

Type locality: Namyit Island , Spratly Islands, Khanh Hoa province, Vietnam, 10°11’03.8’’N, 114°22’05.2’’E, depth 16–18 m. GoogleMaps

Type material. Holotype VNMN M-000.002.348 (shell height 7.4 mm, shell width 2.1 mm, Figs. 2 D–E View FIG ) . Paratype: VRTCM.Ga 27050719.03 (1 shells), Tai-Tu N. (14 shells), same data as holotype .

Etymology: This species is named after the type locality, Namyit Island, Spratly Islands, Khanh Hoa province, Vietnam.

Material examined. South China Sea, Spratly Islands, Vietnam: Lansdowne Reef, on dead corals and under stones, 09°46’37’’N, 114°22’34.8’’E, depth 10 m, coll. Tai-Tu N, 19.5.2019, VRTCM.Ga 27051619.02 (3 shells); Pearson Reef, on dead corals and under stones, 08°57’24.1’’N, 113°41’31.2’’E, depth 18–21 m, coll. Tai-Tu N, 23.5.2019, VRTCM.Ga 27050619.02 (1 shell); Barque Canada Reef, on dead corals and under stones, 08°16’35.3’’N, 113°21’10.7’’E, depth: 12 m, coll. Tai-Tu N., 29.5.2019, VRTCM.Ga 27051019.02 (2 shells); on dead corals and under stones, 08°15’52.2’’N, 113°21’45.5’’E, depth: 6–8 m, coll. Tai-Tu N, 29.10.2020, VRTCM.Ga 27051020.02 (2 shells); on dead corals and under stones, 08°16’54.4’’N, 113°21’51.8’’E, depth: 8–9 m, coll. Tai-Tu N., 30.10.2020, VRTCM.Ga 27051020.03 (3 shells); Alison Reef, on dead corals and under stones, 08°49’7.04’’N, 113°57’6.73’’E, depth: 2 m, coll. Tai-Tu N, 25.5.2019, VRTCM.Ga 27050719.02 (2 shells); on dead corals and under stones, 08°49’47.8’’N, 113°56’3.2’’E, depth: 3 m, coll. Tai-Tu N, 27.5.2019, VRTCM.Ga 27050719.03 (3 shells) GoogleMaps .

Diagnosis. The shell is rather long, cyrtoconoid, flat above and convex below. The teleoconch is yellowish brown with white blotches on the first spiral cord, white granules on the second spiral cord, and reddish brown between spiral cords 1–3. The first whorl of protoconch has numerous hemispherical granules. Teleoconch has 13 whorls, with three spiral cords. The second spiral cord is weakly granular, appearing on the first teleoconch whorl. Spiral microsculpture of fine threads and weakly axial riblets that are present between the main spiral cords. The last whorl has 34–36 axial ribs. Base with two additional weakly tuberculed spiral cords ( Fig. 5C, S View FIG 1–S View FIG 2 View FIG ).

Description. The shell is rather long, cyrtoconoid, flat above and convex below. The teleoconch is yellowish brown with white blotches on the first spiral cord, white granules on the second spiral cord, and reddish brown between spiral cords 1–3; protoconch reddish brown. The protoconch has 6 whorls, the first whorl with hemispherical granules, whorls 2–4 with one median spiral thread, and whorls 5–6 with 2 median spiral threads, uninterrupted axial riblets on protoconch whorls. Teleoconch has 13 whorls, with three spiral cords. First and third spiral cords are smooth, granulated on the first teleoconch whorl.The second spiral cord is weakly granular, appearing on the first teleoconch whorl. Spiral microsculpture of fine threads and weakly axial riblets that are present between the main spiral cords. The last whorl has 34–36 axial ribs. Base with two additional weakly tuberculed spiral cords ( Fig. 5C, S View FIG 1–S View FIG 2 View FIG ). Peristome with an additional tuberculed spiral cord ( Fig. 5D View FIG ,

Sp1). Outer lip thick and flared. Anterior siphonal canal oblique, subtubular, long.

Measurements. SH: 7.4–8.4 mm; SW: 2.1–2.5 mm (n = 2).

Distribution. This species is known from Spratly Islands, Khanh Hoa province, Vietnam.

Ecology. This species collected under stones and on dead corals.

Remarks. Viriola namyitensis n. sp. is superficially similar to V. cancellata ( Hinds, 1843) . However, V. namyitensis n. sp. differs from V. cancellata in having the shell cyrtoconoid, flat above, convex below, base rather wide ( vs. the shell cyrtoconoid with flat sides); the first whorl of protoconch has numerous hemispherical granules ( vs. the first two whorls of protoconch have numerous hemispherical granules); the second spiral cord appears on the first teleoconch whorl ( vs. the second spiral cord appears on the second teleoconch whorl); spiral microsculpture of fine threads and axial ribs ( vs. axial ribs); the last whorl has 34–36 axial ribs ( vs. 28–30 axial ribs); the base with two additional weakly tuberculed spiral cords ( vs. the base with an additional granulated spiral cord and a small, smooth spiral cord).