VENUS 64 (3-4): 141-149, 2005

Two New Species of the Family () from Japan

Yoshihiro Omi1 and Takeshi Iino2 14-20-8-4 Sendagaya, Shibuya-ku, Tokyo 151-0051, Japan; [email protected] 21-8-10-405 Daidominami, Higashi-yodogawa-ku, Osaka 533-0012, Japan

Abstract: Two new species of the family Ovulidae are described from off the Kii Peninsula, from Kuchinoshima Island and the Oshima-Shin-Sone Bank, Japan. astra n. sp. is closely similar to Primovula oryza Omi & Clover, 2005 in overall morphology, but it can be distinguished by its non-beaked posterior extremity and different dorsal marking. vitrea n. sp. is most similar to Phenacovolva tayloriana Azuma & Cate, 1971, but differs from it in forming short and callously rimmed terminals, and having less flared margin.

Keywords: Ovulidae, new species, Japan, Primovula astra, Phenacovolva vitrea

Introduction

All ovulid species are ectoparasites on octocorallian coral, such as gorgonaceans, alcyonaceans and pennatulaceans. According to Imahara (1994), 621 octcorallians have been recorded from Japanese waters. The octocorallian fauna is known to be especially rich around the Kii Peninsula, which is strongly influenced by the Kuroshio Current and is home to 160 species (Kubota & Imahara, 2004). Reflecting the abundance of octocorallians, this area is also known to have a rich ovulid fauna. Among the 127 ovulid species that have been recorded from Japanese water, 58 species were described from the Kii Peninsula as the type locality, mostly in the years between 1970 and 1990 (Higo et al., 1999). More recently, additional new species were described by Omi & Clover (2005) and Omi (2003) from this area and the area influenced by Kuroshio Current. In examining ovulid specimens collected from this area, we found two additional possibly undescribed species, although all the specimens at our disposal were empty shells. Mase (1989) demonstrated some intraspecific variabilities in shell morphology, and pointed out the importance of soft part characters, such as external morphology and coloration of the , for not only species but also level classification. Nevertheless, some of the shell characters still have important systematic significance, and detailed examination of the shells of these species and comparison with those of related species has led us to the conclusion that they are distinct from all the previously named species. Accordingly descriptions of these new species are given in following lines.

Abbreviations: Coll. – collection; SL – shell length; NSMT – National Science Museum, Tokyo.

Taxonomy

Family Ovulidae Fleming, 1828

Genus Primovula Thiele, 1925 Type species: Amphiperas beckeri Sowerby, 1900, by original designation. 142 Y. Omi & T. Iino

Primovula astra n. sp. (Figs. 2A-M)

Type materials: Holotype (NSMT-Mo 73722) dredged from off Cape Shiono-Misaki, Kushimoto-Cho, Wakayama Prefecture, Japan at a depth of 110 m (33˚26´ N, 135˚46´ E), January 5, 1998, collected by M. Tanaka; paratype #1 (NSMT-Mo 73723a) and paratype #2 (NSMT- Mo 73723b) dredged from Hira-se Shoal, N. of Kuchinoshima Island, Japan at a depth of 80 m (30˚06.00´ N, 130˚03.40´ E), May 21, 2003, collected by K. Hasegawa (T/S Toyoshio-Maru St. TY-03-04); paratype #3 (NSMT-Mo 73724a), paratype #4 (NSMT-Mo 73724b) and paratype #5 (NSMT-Mo 73724c) dredged from Oshima-Shin-Sone Bank, Japan at a depth of 163-167 m (28˚52.14´ N, 129˚32.99´ E), May 27, 2003, collected by K. Hasegawa (T/S Toyoshio-Maru St. TY-03-15); paratype #6 (Coll. Y. Omi) from off Inami, Hidaka-gun, Wakayama Prefecture, Japan (33˚48´ N, 135˚14´ E) in March 1978, by S. Habu; paratype #7 (Coll. T. Iino) dredged from off Cape Shiono-Misaki, Kushimoto-Cho, Wakayama Prefecture, Japan at a depth of 110 m (33˚ 26´ N, 135˚46´ E), December 19, 1992, collected by M. Tanaka; paratype #8 (Coll. M. Tanaka) collected alive from off Kuroshima, Cape Shiono-Misaki, Kushimoto-Cho, Wakayama Prefecture, Japan (33˚26´ N, 135˚46´ E), February 18, 1979, by M. Tanaka; paratypes #9 and #10 (Coll. M. Tanaka) dredged from off Cape Shiono-Misaki, Kushimoto-Cho, Wakayama prefecture, Japan at a depth of 110 m (33˚26´ N, 135˚46´ E), January 5, 1998, collected by M. Tanaka (Fig. 1). Paratypes #9 and #10 are juvenile shells with incomplete terminal ridges; numerous incised transverse striations on the dorsum extend over the columellar surface on the ventral side. Description: Shell small, rhomboid, broadest at approximately 1/3 position from posterior end, where angled shoulder transverses dorsum, gradually attenuate toward anterior extremity. Dorsum heavily and evenly incised with numerous spiral striations over entire surface. Anterior terminal square, callously rimmed and slightly pointed on corner. umbilicate centrally, laterally elevated on marginal portion, thickened and forming callus at posterior end of dorsum. Posterior terminal abruptly tapered, squared and rimmed on tip. Right margin callously rimmed, extending over both extremities. Columella inflated, callused, smooth, constricted in front. Anterior terminal ridge twisted and prominent. Triangular funiculum, upraised on edge. Long concave columellar peristome, smooth on surface, narrowly depressed in middle, connected to fossula. Outer lip weakly dentating anterior two-thirds, three strong denticles protruded from outer periphery of posterior portion. Aperture narrow, expanded anteriorly, open straight and flared at both ends. Shell color pinkish white overall. Dorsum marked with seven punctations of brownish orange, pigmented with faint fine yellow line along angles of labral shoulder extending over extremities. Both extremities and marginal rims white. Ventral side marked by transverse faint yellow band at the middle of columella. Funiculum and labrum white. Fossula pigmented with orange. Dimensions (Length × width × height in mm): Holotype – 4.5 × 2.2 × 1.9. Paratype #1 – 6.5 × 3.6 × 3.3. Paratype #2 – 6.3 × 3.5 × 3.2. Paratype #3 – 4.9 × 2.6 × 2.5. Paratype #4 – 4.9 × 2.5 × 2.2. Paratype #5 – 4.8 × 2.3 × 2.1. Paratype #6 – 5.5 × 3.1 × 2.8. Paratype #7 – 5.9 × 3.3 × 3.1. Paratype #8 – 5.7 × 3.1 × 2.6. Paratype #9 – 8.0 × 4.7 × 4.2. Paratype #10 – 6.5 × 3.6 × 3.1. Type locality: Off Cape Shiono-Misaki, Wakayama Prefecture, Kii Peninsula, Japan, 110 m depth. Distribution: Off Inami and Cape Shiono-Misaki on Kii Peninsula; off Kuchinoshima Island; on Oshima-Shin-Sone Bank (Fig. 1). Etymology: The species name is derived from the Latin “astra”, meaning “constellation”, referring to the image of bright orange spots on the dorsum. Remarks: The genus Primovula was originally proposed based on the type species Amphiperas beckeri Sowerby, 1900 by Thiele (1925), who gave the diagnostic features as follows: “Shell Two New Species of Ovulidae from Japan 143

Fig. 1. Localities for Primovula astra n. sp. ( ● ) and vitrea n. sp. ( ▲ ). small, pyriform; aperture narrow; outer lip distinct, thickened, denticulate; funiculum distinct, fully developed”. The present new species is basically consistent with this definition except for the shorter and rhomboid shell outline. The present new species most closely resembles Primovula oryza Omi & Clover, 2005 (Figs. 2N, O), in sharing the following characters: shell rhomboid in shape with angulate shoulder; columella with a thick callus, and distinct triangular funiculum near the posterior end; several protruding labral denticles at the posterior portion. However, the present new species is distinguished from P. oryza by the following features: the posterior end of the new species is simply cut, and is not pointed like a beak as in P. oryza. The new species is markedly characterized by having seven reddish orange dorsal spots, and possesses an oblong callus near the spire at the posterior portion of the dorsum (Fig. 3A). The posterior portion of P. astra is formed into a step by the elevated callus (Fig. 3A), whereas the same portion of P. oryza is gradually attenuated and produces a beaked posterior end (Fig. 3B). Also, the maximum elevation of the dorsum of P. astra is at approximately 2/3 from the 144 Y. Omi & T. Iino

Fig. 2. Primovula astra n. sp. (A-M) and Primovula oryza (N, O). A-C. Primovula astra n. sp. Holotype from Wakayama Prefecture (NSMT-Mo 73722), SL = 4.5 mm. D, E. Do. Paratype #2 from Hira-se off Kuchinoshima Island (NSMT-Mo 73723b), SL = 6.3 mm. F, G. Do. Paratype #3 from Oshima-Shin- Sone Bank (NSMT-Mo 73724a), SL = 4.9 mm. H, I. Do. Paratype #6 from Wakayama Prefecture (Coll. Y. Omi), SL = 5.5 mm. J, K. Do. Paratype #8 from Wakayama Prefecture (Coll. M. Tanaka), SL = 5.7 mm. L, M. Do. Paratype #10 juvenile from Wakayama Prefecture (Coll. M. Tanaka), SL = 6.5 mm. N, O. Primovula oryza Holotype from Ogasawara Islands (NSMT-Mo 73638), SL = 9.0 mm. Two New Species of Ovulidae from Japan 145

Fig. 3. Comparison of Primovula astra n. sp. Paratype #8 (Coll. M. Tanaka), SL = 5.7 mm (A) and Primovula oryza Paratype #1 (NSMT-Mo 73639), SL = 8.0 mm (B) from Wakayama Prefecture. The arrow indicates the callus near the spire on dorsum of Primovula astra. anterior end and more round (Fig. 3A) but that of P. oryza is at 3/4 and more angular (Fig. 3B). These features can also be observed in immature shells. The new species also forms a prominent terminal ridge. Primovula dorsuosa (Hinds, 1844) is another similar-looking ovulid hitherto known from the western Pacific. However, P. dorsuosa differs from the new species by lacking a callus near the spire, terminal crenulation and dorsal spots. Primovula roseomaculata (Schepman, 1909) also superficially resembles the present new species in possessing dorsal spots, but differs by lacking the callus near the spire, distinct triangular funiculum and strong labral denticles.

Genus Phenacovolva Iredale, 1939 Type species: Phenacovolva nectarea Iredale 1930, by original designation.

Phenacovolva vitrea n. sp. (Fig. 4A-J)

Type materials: Holotype (NSMT-Mo 73725) collected alive in gill-net set for Japanese spiny lobster Panulirus japonicus (Siebold, 1824), off Minabe, Wakayama Prefecture, Japan (33˚45´ N, 135˚19´ E), February 9, 1986, by M. Tanaka; paratype #1 (NSMT-Mo 73726) collected alive in gill-net, from off Minabe, Wakayama Prefecture, Japan (33˚45´ N, 135˚19´ E), March 16, 2003, by T. Iino; paratype #2 (Coll. T. Iino) collected alive by gill-net, off Inami, Hidaka-gun, Wakayama Prefecture, Japan (33˚48´ N, 135˚14´ E), February 2, 2003, by T. Iino; paratype #3 and #4 (Coll. M. Tanaka) collected alive in gill-net, off Minabe, Wakayama Prefecture, Japan (33˚ 45´ N, 135˚19´ E), February 9, 1986, by M. Tanaka; paratypes #5 (Coll. Y. Omi) from 60-70 m, off Minabe, Wakayama Prefecture, Japan (33˚45´ N, 135˚19´ E), February, 1998, by S. Habu, in gill-net (Fig. 1). 146 Y. Omi & T. Iino

Fig. 4. Phenacovolva vitrea n. sp. (A-J) and Phenacovolva tayloriana (K, L) from Wakayama Prefecture. A-D. Phenacovolva vitrea n. sp. Holotype from off Cape Shiono-Misaki (NSMT-Mo 73725), SL = 11.1 mm. E, F. Do. Paratype #1 from off Minabe (NSMT-Mo 73726), SL = 9.8 mm. G, H. Do. Paratype #2 from off Inami (Coll. T. Iino), SL = 11.3 mm. I, J. Do. Paratype #3 from off Minabe (Coll. M. Tanaka), SL = 11.1 mm. K, L. Phenacovolva tayloriana from off Sakai (Coll. Y. Omi), SL = 11.3 mm. Two New Species of Ovulidae from Japan 147

Description: Shell small, narrowly rhomboid. Body whorl thin, glassy. Dorsum incised with numerous fine transverse striations over the terminals. Transverse striations become more prominent towards the extremities. Right margin curved, rimmed along the labrum, broader towards the extremities. Anterior terminal long, gradually tapered, slightly twisted to the right. Anterior extremity square, arched and rimmed. Posterior terminal well developed, rapidly attenuate, slightly curving upward, rimmed on tip. Ventral side glossy, smooth and thickened. Columella inflated, elongated, anteriorly constricted, and narrowly extended. Columellar peristome thin, connected to fossula. Outer lip edentate, constricted in front. Aperture narrow, expanded anteriorly and flared at tips. Shell color translucent white overall. Anterior and posterior portion of dorsum pinkish orange in color. Columellar peristome to fossula tinted with pinkish orange, visible from dorsal aspect. Infraspecific variations: Significant infraspecific variations were observed among the type specimens: The posterior rostrum exhibits different degrees of development. Paratype 5 has distinct incised transverse striations on the dorsum, and paratype 3 and 4 are incised on both dorsal and ventral sides, which may be due to immaturity. Dimensions (Length × width × height in mm): Holotype – 11.1 × 2.8 × 2.5. Paratype #1 – 9.8 × 2.5 × 2.3. Paratype #2 – 11.3 × 3.1 × 2.8. Paratype #3 – 11.1 × 3.3 × 2.7. Paratype #4 – 8.7 × 2.8 × 2.2. Paratype #5 – 10.1 × 2.9 × 2.5. Type locality: Off Minabe, Kii Peninsula in Wakayama Prefecture, Japan, 60-70 m depth. Distribution: Known only from two localities, Inami and Minabe in Wakayama Prefecture (Fig. 1). Etymology: The species name is derived from Latin adjective vitreus that means “glassy”, referring to the translucent body whorl of this shell. Remarks: The present new species is characterized by a narrow and lanceolate shell with thickened rims on both terminal ends. Also the anterior extremity of the outer lip is slightly pointed out and forming terminal ridge. The present new species has determinate shell growth; terminal ends thicken or become rimmed after maturity, and cease growing in length. This particular shell feature is seen in the species included in the narrow sense in the genera Dissona Cate, 1973 and Hiatavolva Cate, 1973, and there might be the possibility of a relationship to these groups. However, these groups are also considered to belong to the genus Phenacovolva sensu lato because of the taxonomic features are not sufficient for separation from Phenacovolva. Callomon (2005) treated Hiatavolva as a synonym of Phenacovolva. The genus Phenacovolva was originally proposed based on the type species Phenacovolva nectarea Iredale 1930 by Iredale (1935), who gave the diagnostic features as follows: “Shells in this genus are narrowly ovate centrally, with narrow lanceolate terminal processes at either end of the shell”. The present new species is basically consistent with this definition, and it thus assigned to the genus Phenacovolva. The present new species most closely resembles Phenacovolva tayloriana (Azuma & Cate, 1971) (Figs. 4K, L), which is distributed over almost the same range off the Kii Peninsula. They share common characters, such as the small and glassy translucent shell. However, the present new species is distinguished from P. tayloriana by having a less flared margin, straight or slightly bent outward columellar ends, a short anterior terminal, squared and thickened terminal rim, and the labrum slightly protruding from the edge of the anterior end. Among the similar-looking ovulids hitherto known from western Pacific waters, Dissona hasta Cate & Azuma, 1973 resembles the present new species. However, D. hasta differs from the present new species in having a thickened shell with a brown posterior terminal, oblique angled anterior extremity, broad and flat columella and semi-enclosed terminal canal. D. reflexa Cate, 1973, described from the Philippines, is also similar to the new species, but can be separated 148 Y. Omi & T. Iino therefrom by having a funicular projection on the posterior side of the columella.

Acknowledgements

We are grateful to Mr. Makoto Tanaka, Wakayama, for providing us with invaluable specimens: Dr. Takashi Okutani, Emeritus Professor at Tokyo University of Fisheries and Dr. Kazunori Hasegawa at the National Science Museum, Tokyo for valuable comments that improved the manuscript. We also thank the following persons who helped us in various ways: Mr. Yukimitu Imahara of Wakayama Natural History Museum, Mr. Shingo Habu in Wakayama, Mr. Hitoshi Ikeda of Hayama Shiosai Museum in Kanagawa, and Mr. Kin’ya Mase in Kamakura City.

References

Azuma, M. & Cate, C. N. 1971. Sixteen new species and one new genus of Japanese Ovulidae. The Veliger 13: 261-268. Callomon, P. 2005. Phenacovolva brunneiterma (Cate, 1969): First record from Japan (Gastropoda: Ovulidae). Venus 63: 153-155. Cate, C. N. 1973a. A systematic revision of the Recent family Ovulidae (: Gastropoda). The Veliger, Supplement 15: 1-116. Cate, C. N. 1973b. The Ovulidae: Replacement names for four ovulid homonyms. The Veliger 16: 238-239. Higo, S., Callomon, P. & Goto, Y. 1999. Catalogue and Bibliography of the Marine Shell-bearing Mollusca of Japan. Elle Scientific Publications, Osaka. 749 pp. Imahara, Y. 1994. Octocorals of Japan. Marine Parks Journal (103): 3-8. (in Japanese) Iredale, T. 1935. Australian . Australian Zoologists 96-135, pls. 8-9. Kubota, S. & Imahara, Y. 2004. A checklist of the Octocorals (Cnidaria, ) recorded in the coasts of the Kii Peninsula. Annual report of the Seto Marine Biological Laboratory 17: 32-36. (in Japanese) Mase, K. 1989. Taxonomic significance of color patterning of the soft body in the family Ovulidae – Description of soft body of 26 species. Venus, Supplement 1: 75-120. (in Japanese with English abstract) Omi, Y. 2003. A new species of (Gastropoda) collected near the Boso Peninsula, Japan. Venus 62: 11-18. Omi, Y. & Clover, P. W. 2005. Description of a new species of Primovula (Gastropoda: Ovulidae), with the designation of the type species for the genus . Venus 63: 101-108. Thiele, J. 1925-1926. Solenogastres・ Mollusca・ Echinodermata in Kükenthal, W. Handbuch der Zoologie 5 (1), Teil 1-3: 256 pp. Berlin, Germany.

(Received February 14, 2005 / Accepted October 25, 2005) Two New Species of Ovulidae from Japan 149

日本近海で採集されたウミウサギ科の 2 新種

淤見慶宏・飯野 剛

要 約

紀伊半島沖，口の島沖，奄美大島沖の刺網漁混獲物及びドレッジ採集物から採集されたウミウサギ科 2 新種類を記載する。

Primovula astra n. sp. イサリビケボリ（新称：漁火毛彫） 殻長 4.5 ～8.0 mm。本種貝殻は以下の特徴がある。背面に 7 つの橙色斑が並ぶ，臍状に陥没した螺 搭の側縁部が滑層の肥厚により横方向に盛りあがる，背面に明確な螺条が刻まれる，三角形の滑層痕 （funiculum）を形成する，内外唇の前端内側の滑層が肥厚し末端襞を形成する，外唇後端側に強い外唇歯 が形成されるなどの特徴をもつ。本種はヤエバケボリ Primovula oryza Omi & Clover, 2005 に似るが，後 端が嘴状にならない点，背面に 7 つの斑点が出現する点，螺搭陥没痕が滑層で肥厚する点，末端襞がね じれて形成される点などで明瞭に区別される。 タイプ標本：ホロタイプ，NSMT-Mo 73722，殻長 4.5 mm。パラタイプ No. 1，NSMT-Mo 73723a，殻長 6.5 mm。パラタイプ No. 2，NSMT-Mo 73723b，殻長 6.3 mm。パラタイプ No. 3，NSMT-Mo 73724a，殻 長 4.9 mm。パラタイプ No. 4，NSMT-Mo 73724b，殻長 4.9 mm。パラタイプ No. 5，NSMT-Mo 73724c， 殻長 4.8 mm。 タイプ産地：和歌山県西牟婁郡串本町潮岬沖，水深 110 ｍ。 み な べ 分布：紀伊半島南部沖，潮岬沖，口之島沖，大島新曽根。

Phenacovolva vitrea n. sp. ビードロマメヒガイ（新称：玻璃豆杼貝） 殻長 8.7 ～11.3 mm。本種貝殻は以下の特徴がある。薄く半透明となる，内唇の膨らみが前後に向かっ て急速に窄まる，外唇縁の肥厚に連続して前端が反転し角ばり肥厚する，内唇縦溝・軸唇窩は橙色に彩 色され，背面側からも透過して見える，殻口が前菅溝手前で湾曲して広がる，前後溝の先端が開くなど の特徴がある。 本種はテイラーキヌヅツミ Phenacovolva tayloriana (Azuma & Cate, 1971) に似るが，前後端が角ばり滑 層の肥厚により縁取られる点，背面外唇側が前端手前で広がらない点などで容易に区別される。また， 本種はヤリクビレキヌヅツミ Dissona hasta Cate & Azuma, 1973 にも似るが，後種は殻が厚く，前端が斜 めに切れており，後端が褐色に彩色され，腹面が幅広く扁平になる点，水管が半閉じとなる点などで異 なる。 タイプ標本：ホロタイプ，NSMT-Mo 73725，殻長 11.1 mm。パラタイプ No. 1，NSMT-Mo 73726，殻 長 9.8 mm。 み な べ タイプ産地：和歌山県御坊市南部沖，水深 60 ～ 70 m。 み な べ 分布：紀伊半島南部沖。