46 VENUS 70 (1–4), 2012 ©Malacological Society of Japan

A New Species of the Family Epitoniidae in the Nagai Collection in Wakayama Prefectural Museum of Natural History (II)

Taisei Nakayama 997-53 Fuke, Misaki, Osaka 599-0303, Japan; [email protected]

The late Mr. Seiji Nagai’s molluscan collection body whorl with an intritacalax. Aperture elliptical, is now preserved in the Wakayama Prefectural with double peristome and thick lip. Umbilicus Museum of Natural History (WMNH), and it slightly perforated. contains large number of unstudied and unidentified Type locality: Off Shionomisaki, Kii Peninsula, specimens, especially in the families Epitoniide and 33°25´N, 135°47´E, at a depth of about 160 m. Turridae (s.l.) (Nakayama, 2010). The author Distribution: Off Kii Peninsula, Japan, 80–160 m. formerly described a new epitoniid, Opalia levis, Type materials: Holotype, WMNH-Mo-Na-46, based on specimens in the collection (Nakayama, height 10.3 mm, breadth 3.5 mm (Figs. 1–2); 2010). Further investigation of the collection paratype 1, WMNH-Mo-Na-47, height 10.0 mm, resulted in the finding of another undetermined breadth 3.2 mm (Fig. 3); paratype 2, WMNH-Mo- Opalia species, which was collected from off the Ko-1, height 11.0 mm; breadth 4.0 mm (Fig. 4). Kii Peninsula, Japan, and is similar to O. levis. Remarks: The present new species is similar to Although only two specimens were found in the Opalia levis Nakayama, 2010 (Figs. 5–6) in overall Nagai collection, another specimen from the same shell morphology, but is distinguished by having region was subsequently found in Mr. Yasuo distinct axial ornamentation at the suture. Regarding Koyama’s collection, which was also donated to the the generic position of these species, they can be WMNH. Detailed comparison of the three assigned to a group containing the genera Opalia H. specimens with Opalia levis revealed that they & A. Adams, 1853, Gregorioscala Cossmann, 1912 represent a distinct species, and it is described and Compressiscala Masahito & Habe, 1976 in herein as new to science. possessing intritacalax on the shell surface and a thick peristome, which characterize these genera Taxonomy (Kilburn, 1985). Among them, they can be assigned to Opalia, in having pitted intritacalx that is Family Epitoniidae Berry, 1910 regarded by Bouchet & Warén (1986) as the most Genus Opalia H. & A. Adams, 1853 important character to characterize the genus. Although several authors prefer to subdivide the Opalia calyx n. sp. genus Opalia into several subgenera, such as (Figs. 1–4) Nodiscala de Boury, 1889 and Pliciscala de Boury, 1887 (e.g., Kilburn, 1985), the taxonomical Description: Shell narrowly acuminate, usually relationships among these subgenera still remain straight, moderately thick, pale gray or chalky white unclear, because of the absence of detailed in color. Protoconch slightly eroded in all specimens morphological, especially anatomical, characters, examined, but probably blunt and subcylindrical. and genetic data, as mentioned in the former study Teleoconch with about 9 convex whorls. Suture (Nakayama, 2010). Accordingly this new species is impressed and occasionally covered with sepal-like assigned only to the genus Opalia, until a firmer ribs. Base obscurely angulated below periphery, higher taxonomical framework becomes available. forming indistinct basal disc. Axial sculpture Among the known species, the present new consisting of weak axial ribs and microscopic spiral species resembles Opalia (Pliciscala) aglaia threads and pits. Axial ribs round and weak, and (Bartsch, 1915), which was originally described sequent to the sepal-like ornament on sutures, about from Port Alfred, South Africa and illustrated in 14 in number on 3rd teleoconch whorl, becoming detail by Kilburn (1985: figs. 11–12), but it is easily more indistinct towards body whorl. Occasionally distinguishable by the sepal-like axial ornament at varices present, usually irregular. Spiral sculpture the suture. Opalia spongiosa Carpenter, 1866, consisting of fine dots, lines and threads, 15–25 on described from off Cooper, Monterey, California, Short Notes 47

Figs. 1–4. Opalia spp. 1–4, Opalia calyx n. sp.; 1–2, holotype, WMNH-Mo-Na-46, height 10.3 mm, breadth 3.5 mm. 3, paratype 1, WMNH-Mo-Na-47, height 10.0 mm, breadth 3.2 mm. 4, paratype 2, WMNH-Mo-Ko- 1, height 11.0 mm, breadth 4.0 mm. 5–6. Opalia levis Nakayama, 2010, holotype, WMNH-Mo-Na-765, height 11.0 mm, breadth 3.5 mm. Scale = 2 mm (all at the same scale). 48 VENUS 70 (1–4), 2012

USA (holotype was illustrated by Palmer, 1958: pl. 22, figs. 1–3), also closely resembles the present 和歌山県立自然博物館の new species, but O. spongiosa is distinguishable by 永井コレクションに含まれる its relatively thicker outer lip and more distinct axial 日本産イトカケガイ科の 1新種（2） ribs with nodule-like projections at the suture. Etymology: The name calyx is derived from the 中山大成 sepal-like ribs at the suture.

Acknowledgments: I am very grateful to Mr. 要 約 Makoto Yoshida, co-principal of Wakayama Prefectural Museum of Natural History, for taking 和歌山県立自然史博物館に所蔵されている永井 photos used in this study, and also for allowing me 誠二氏のコレクション中の不詳種を検討中に見出 to examine the specimens in the Nagai and Koyama 1 collections preserved in the museum. I also thank された日本産イトカケガイ科の 新種を記載する。 Mr. Yasuo Koyama, for donating his valuable なお同種は同博物館に寄贈された小山安夫氏のコ collection to WMNH. レクションにも見出された。 Opalia calyx n. sp. ウテナイトカケガイ References （新種，新称） 殻は 10～12 mm の小型で厚く，尖塔形。灰白色。 Bouchet, P. & Warén, A. 1986. Revision of the Northeast Atlantic bathyal and abyssal 各層に不規則な縦張肋をなす。胎殻は平滑で円錐 Aclididae, Eulimidae, Epitoniidae (Mollusca, 形，浸蝕されていることが多い，体層は弱い底盤 Gastropoda). Bolletino Malacologico, 9 supplemento (2): 486–576. を形成する。次体層は 層内外で，殻表は繊細な Kilburn, R. N. 1985. The family Epitoniidae 微穴からなる螺列と非常に弱い縦肋を持ち縦肋は (Mollusca: Gastropoda) in southern Africa and 直上の縫合を蕚状に覆う。殻口は 2重，楕円形で Mozambique. Annals of the Natal Museum 27: 239–337. 外唇厚くなるが著しい張り出しにはならない。 Nakayama, T. 2003. A Review of Northwest Pacific タイプ標本：ホロタイプ，殻高 10.3 mm; 殻径 Epitoniids (Gastropoda: Epitoniidae). 3.5 mm（WMNH-Mo-Na-46）；パラタイプ 1，殻高 Monographs of Marine Mollusca (6), vii + 143 pp. Backhuys Publishers, Leiden. 10.0 mm，殻径 3.2 mm（WMNH-Mo-Na47）；パラ Nakayama, T. 2010. A new species of the Family タイプ 2，殻高 11.0 mm，殻径 4.0 mm（WMNH- Epitoniidae in the Nagai Collection in Mo-Ko-1）。 Wakayama Prefectural Museum of Natural History. Venus 68: 173–175. タイプ産地：和歌山県串本町沖，水深 160 m。 Palmer, K. van W. 1958. Type specimens of marine 分布：紀伊半島沖水深 80～160 m。 Molluca described by P. P. Carpenter from the 比較：本種に最も近似するカタイトカケガイ West Coast (San Diego to British Columbia). Memoir of the Geological Society of America Opalia levis Nakayama, 2010は体層に明瞭な底盤を 76: 1–376. もつが，本種は底盤が不明瞭，また本種では縫合 Weil, A., Brown, L & Neville, B. 1999. The まで伸びる縦肋が蕚（うてな）状に覆うことが大 Wentletrap Book. 244 pp. Evolver, Rome. きく異なる。本種の和名はこの特徴により命名し た。