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Home , Apicalia, Echineulima, Eulimidae, Fusceulima, Monogamus, Parvioris

©The Malacological Society of Japan DOI: http://doi.org/10.18941/venus.78.1-2_61 Short Notes December 25, 201961

New Species of Vitreobalcis (: : ) Parasitic on gratilla (Echinodermata: : ) in Japan

Haruna Matsuda1* and Kazuya Nagasawa2 1Center for Faculty-wide General Education, Shikoku University, 123-1 Ebisuno, Furukawa, Ojin-cho, Tokushima, Tokushima 771-1192, Japan; *@gmail.com 2Aquaparasitology Laboratory, 365-61 Kusanagi, Shizuoka 424-0886, Japan

Caenogastropods of the family Eulimidae are by Hikaru Kawano from T. gratilla on the Pacific known to be parasitic on including coast of Tokushima Prefecture, Japan. Although the holothuroids, ophiuroids, crinoids, asteroids eulimid from T. gratilla was initially identified as and echinoids (Warén, 1984). The eulimids of E. akauni (e.g., Habe, 1976, 1989), comparison of each are usually found on echinoderms these specimens with E. akauni reveals that they in a single class. The family currently consists are a distinct species. This paper describes the of 106 genera, 16 of which (Clypeastericola, specimens as a new species of Vitreobalcis. , Eulitoma, , Hypermastus, Three types and five other specimens examined Microeulima, , Nanobalcis, , are deposited in the molluscan (Mo) collection of the Pulicicochlea, Robillardia, , Trochostilifer, NSMT. For comparison, the holotype of E. akauni Turveria, Vitreobalcis and ) have been (NSMT-Mo 39830) and one specimen of E. akauni reported to be associated with echinoids (Warén, (NSMT-Mo 79110) collected by Hikaru Kawano 1981a, 1984, 1992; Bouchet & Warén, 1986; Warén from the Pacific coast of Kochi Prefecture at Nabae & Mifsud, 1990; Warén et al., 1994; MolluscaBase, (Muroto) on 2 August 2009 were also examined. 2019). Their parasitic mode ranges from temporal Abbreviations: AE, aperture anterior extension ectoparasitism to permanent endoparasitism. (distance from the anteriormost end of the columellar Eleven valid species of eulimids are known to lip to the anteriormost end of the aperture); BL, occur on the surface of regular sea urchins in Japanese body whorl length; L, distance from the posterior waters (see Hori & Matsuda, 2017). They are extremity of the outer lip margin to the widest Hypermastus araeosomae (Habe, 1992), Eulitoma point along OL; OL, chord of the outer lip margin akauni (Habe, 1952), E. langfordi (Dall, 1925), (distance from the posterior extremity to the anterior Vitreobalcis temnopleuricola Fujioka & Habe, 1983, extremity of the outer lip margin); SL, shell length; Echineulima mittrei (Petit de la Saussaye, 1851), SW, shell width (see Matsuda et al., 2010: fig. 1A, E. robusta (Pease, 1861), E. tokii (Habe, 1974), B, D). Pelseneeria castanea (Dall, 1925), P. yamamotoi (Habe, 1952), Trochostilifer atriatus (Hedley, 1905) and Vitreolina aurata (S. Hirase, 1920). Some species are host-specific, while others are found Family Eulimidae Philippi, 1853 on several hosts. An example of the latter group, V. Genus Vitreobalcis Warén, 1980 aurata, parasitizes five species of regular (Heliocidaris tuberculata, Anthocidaris crassispina, Vitreobalcis tripneusticola n. sp. Hemicentrotus pulcherrimus, Stomopneustes (Figs 1A–F; 2A) variolaris and Pseudocentrotus depressus) (Habe, 1946, 1989; Higo et al., 1999) and is one of the most Type material: Holotype, NSMT-Mo 79105 frequently encountered eulimids in Japan. (Fig. 1A, B), on the surface of Recently, we examined seven eulimid specimens collected by gill nets set for lobsters in the western from the regular sea urchin Tripneustes gratilla North Pacific at Nishi-yuki, Minami, Kaifu, (Toxopneustidae), which have been deposited at the Tokushima Prefecture, Japan, 29 October 2008, leg. National Museum of Nature and Science, Tsukuba H. Kawano; paratype #1, NSMT-Mo 102493 (Fig. (NSMT), Japan, and a single specimen collected 1C, D), on the surface of T. gratilla, collected in http://zoobank.org/urn:lsid:zoobank.org:pub:991A1DC2-BD6A-4326-9CFB-5906EC608286 62 VENUS 78 (1–2), 2019 the western North Pacific Ocean off Sakai, Minabe, collected by gill nets set for lobsters at a depth Wakayama Prefecture, Japan, 6 December 1972, of 40 m in the western North Pacific Ocean, off leg. T. Yamamoto; paratype #2, NSMT-Mo 102490 Minabe, Wakayama Prefecture, Japan, 30 October (Fig. 1E, F), on the surface of T. gratilla collected 1977, leg. T. Habe; NSMT-Mo 79107 (identified as by gill nets set for lobsters, collection site the same “Balcis sp.” on specimen label), from T. gratilla, as that of paratype #1, 23 November 1973, collector collected in the western North Pacific Ocean at unknown. Seto, southern Wakayama Prefecture, 1 December Other material examined: NSMT-Mo 79106 1952, collector unknown; NSMT-Mo 79108, from (given provisional Japanese name “Shirahige-uni- T. gratilla, collected at a drying site for lobster nets, yadori-nina” on specimen label), from T. gratilla, Kushimoto Port, southern Wakayama Prefecture, 24 collection site the same as that of paratypes #1 November 1974, leg. T. Kuribayashi; NSMT-Mo and 2, 28 December 1973, collector unknown; 79109, from T. gratilla, collection site and date NSMT-Mo 102492, on the surface of T. gratilla, unknown, collector unknown.

A B C D E F

1 mm

Fig. 1. Shell morphology of Vitreobalcis tripneusticola n. sp. A–B. Holotype, NSMT-Mo 79105, SL = 3.97 mm. C–D. Paratype #1, NSMT-Mo 102493, SL = 4.01 mm. E–F. Paratype #2, NSMT-Mo 102490, SL = 3.90 mm. A, C, E, Apertural view of shell; B, D, F, Lateral view of shell.

A B

100 µm 100 µm

Fig. 2. Scanning electron micrographs of the protoconch. A. Holotype of Vitreobalcis tripneusticola n. sp., NSMT-Mo 79105. B. Eulitoma akauni, NSMT-Mo 79110, SL = 3.97 mm. Short Notes 63

Description: Shell slender (3.97 and 1.58 mm in found in other genera mentioned previously. In this SL and SW, respectively, for holotype; 3.90–4.01 study, only dried specimens of the new species were and 1.38–1.54 mm for paratypes; 3.32–4.41 and examined and it is thus still necessary to clarify its 1.29–1.71 mm for non-type specimens), conical in mode of . form, glossy, white or semi-translucent yellowish in The genus Vitreobalcis currently contain four color, visceral mass visible through shell (Fig. 1). species, the hosts of three of which are known: Spire almost straight, but slightly flexed as inverted echinoids for V. temnopleuricola Fujioka & Habe, S-shaped curve in lateral view. Suture slightly 1983 and V. holdsworthi (H. Adams, 1874) (Warén, impressed, visible in reflected light. Body whorl 1980, 1984; Fujioka & Habe, 1983) and a holothurian expanded, periphery round, constituting almost for V. laevis Warén, 1980. The last is tentatively half of shell length in holotype (BL/SL = 0.52 for assigned to the genus because its shell is similar holotype; 0.49–0.51 for paratypes; 0.48–0.51 for to that of V. holdsworthi, but its soft parts and thus non-type specimens). Incremental scars very thin, mode of parasitism are unknown (Warén, 1980). appearing 1.2, 2.3, 3.4, 4.5, 5.5 and 6.0 whorls from The new species resembles V. temnopleuricola from outer lip margin in holotype. Protoconch consists Temnopleurus toreumaticus (Temnopleuridae) in of four flattened whorls of increasing diameter, Japan but can be readily separated by its flattened approximately 430 µm in height, separated by apical whorls and more protruding outer lip margin. shallow incremental scars (Fig. 2A). Aperture short, The new species also differs from two other pyriform, extended slight anteriorly (AE = 0.17 congeners, V. holdsworthi from Mespilia globulus mm for holotype; 0.13–0.18 mm for paratypes; in New Caledonia and V. laevis from Synaptula 0.15–0.22 mm for non-type specimens). Columellar lamperti (as “Synaptula purpurea”) in Queensland parietal wall slightly curved or slightly angulated at (Warén, 1980), by the combination of a flattened transition. In lateral view, outer lip margin strongly larval shell and a less convex spire. Vitreobalcis curved with middle to upper part protruding (L/OL = nutans from the West Indies differs from the new 0.43 for holotype; 0.44–0.45 for paratypes; 0.42– species in having a slightly curved shell (Megerle 0.44 for non-type specimens) (Fig. 1B). Operculum von Mühlfeld, 1824). While one eulimid from T. thin, transparent. gratilla in south Vietnam has been reported as Type Locality: Western North Pacific Ocean at Vitreolina sp. (Dgebuadze, 2014), it cannot be Nishi-yuki, Minami, Kaifu, Tokushima Prefecture, compared with the new species because neither a Japan. description nor illustration was given. Distribution: Western North Pacific Ocean off The eulimid collected from T. gratilla in Japanese the coasts of Tokushima and Wakayama prefectures, waters has been reported as E. akauni (Habe, 1976, Japan. 1989). It was originally described by Habe (1952) Etymology: The specific name of the new species as Balcis akauni from Pseudocentrotus depressus is a combination of two words, tripneusti derived (Strongylocentrotidae) but later transferred to from the generic name of the host and Eulitoma by Bouchet & Warén (1986). Habe (1976) cola, meaning an inhabitant. added two more sea urchins, Temnotrema rubrum Remarks: The generic position of Vitreobalcis (Temnopleuridae) and T. gratilla, as the hosts of tripneusticola n. sp. is supported by the conical shell the eulimid. While the species was reported in with rather convex whorls and the short and rounded the original description (Habe, 1952) to have a aperture (see Warén, 1980). Species of Vitreobalcis brown dotted line on the body whorl, Habe (1976) were placed in (Warén, 1980, 1984), but the stated that E. akauni usually has a transparently latter genus is separated from Vitreobalcis by having white shell. Through the examination of eulimid strong scars from the outer lip margin (Warén, specimens from T. gratilla, which were deposited by 1981b). Although some species of and Habe at the NSMT, we confirmed that they possess a Eulitoma were previously included in Vitreobalcis white shell without any dotted line. Although Habe (Habe, 1989), they differ from those of Vitreobalcis (1976) did not designate any specimen as a voucher, in that Parvioris spp. have a small aperture and a E. akauni and the new species are considered to have straight outer lip margin and Eulitoma spp. have flat been confused. The new species and E. akauni share whorls and a larger larval shell. Vitreobalcis spp. similar morphology, such as a slightly flexed shell are known to use a pseudopallium for protecting and a protrusion of the outer lip margin (Figs 1, 3). themselves (Warén, 1980, 1984), which has not been However, the new species can be distinguished from 64 VENUS 78 (1–2), 2019

We are thankful to anonymous reviewers for valuable comments on the manuscript. A B References

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Species at: http://www.marinespecies.org/aphia. シラヒゲウニに寄生する php?p = taxdetails&id = 135 on 2019–06–11. Warén, A. 1980. Description of new taxa of ハナゴウナ科貝類の 1 新種 Eulimidae (Mollusca, Prosobranchia), with シラヒゲウニヤドリニナ（新称） notes on some previously described genera. Zoologica Scripta 9: 283–306. Warén, A. 1981a. Eulimid gastropods parasitic on 松田春菜・長澤和也 echinoderms in the New Zealand region. New Zealand Journal of Zoology 8: 313–324. Warén, A. 1981b. Revision of the genera Apicalia A. 要 約 Adams and Iredale and description of two new genera (Mollusca, Prosobranchia, シラヒゲウニ Tripneustes gratilla に寄生するハナ Eulimidae). Zoologica Scripta 10: 133–154. ゴウナ科貝類は，これまでアカウニヤドリニナ Warén, A. 1984. A generic revision of the family Eulimidae (Gastropoda: Prosobranchia). Eulitoma akauni に同定されてきた。しかし，国立 Journal of Molluscan Studies, Supplement (13): 科学博物館に所蔵されている，シラヒゲウニを宿 1–96. 主とする標本を調べたところ，アカウニヤドリニ Warén, A. 1992. Comments on and description of eulimid gastropods from tropical west America. ナとは形態的に区別でき，未記載種であることが The Veliger 35: 177–194. 判明した。そこで，国立科学博物館所蔵の標本と Warén, A. & Mifsud, C. 1990. Nanobalcis a new 新たに徳島県沿岸で採集された標本に基づき，新 eulimid genus (Prosobranchia) parasitic on 種 Vitreobalcis tripneusticola シラヒゲウニヤドリニ cidaroid sea urchins, with two new species, and comments on Sabinella bonifaciae (Nordsieck). ナ（新称）として記載した。本種は，同属のサン Bollettino Malacologico 26: 1–4. ショウウニヤドリニナ V. temnopleuricola に似るが， Warén, A., Norris, D. R. & Templado, J. 1994. 殻頂近くの後成殻がより扁平で，外唇の突出が強 Descriptions of four new eulimid gastropods い点で区別できる。 parasitic on irregular sea urchins. The Veliger 37: 141–154.

(Accepted October 10, 2019)