The malacological society of Japan

Res VENUS CJap. Jour. Mulac.) VuL 5o. No,2(l991):lel-108

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The Anatomy of PhyllodesmiiL7n seTTatum (Baba, 1949) from Japan (Nudibranchia: Faeelinidae)

Kikutar6 BABA (Shigigaoka 1-11-12, Sango-cho, Ikoma-gun, Nara-ken, Japan 636)

Abstract: A eomprehensive study of the anatomy of PhylZodesmaTu7n, serTat?.{m (Baba, 1949) is presented.

Introduction

The aeolid species Hervia serTata was established by Baba, 1949. Sub- sequently, this species has been mueh diseussed by different authors. In 1955, this species was named as Cratena serrata by Baba. In 1964, this species was made the type of the new genus Bab(za'ella by Risso-Dominguez. In 1981, the genus Babaiella was synonymized with Phyllodesmium Ehrenberg, 1831 by Rudman. This paper forms a taxonomical review of Phyllodes7niu?n serratum from the standpoint of the general ana,tomy of the species.

Aleyltottesmium serratum (Baba, 1949)

(Fig. 1, A-H; PL 1, figs. 1-3)

Synonymy :

Hervia serrata Baba, 1949: 105-106, 179, pL46, figs. 156-157, textifigs. 142-143 (Sagami Bay>. Maenae, 1954a: 9. 29 (comment). Maenae, 1954b: 54 (comment). Er. Marcus, 1958: 60, 62 (comment), Crate7La seTrata. Baba, 1955: 36, 56 (generic name ehange). Baba-iella serrata, Risso-Dominguez, 1964: 223 (generic name ehange), Phyllodesmium serrata. Rudman, 1981: 260 (generie name ehange). Phytlodes77ziu7n serra-tum, Baba, 1990: 202 (list). Material: No. 1. Akazumi, Noto Pen., Aug. 8, 1967, 1 specimen eoll. by Takaoka Biol. Club, 12mm; No. 2. Echizen-cho, Eehizen coast, Aug, 12, 1966, several speeimens coll. by Takaoka Biol. Club, 10 mm (partly prepared in H. S.) ; No. 3. Kada, Osaka Bay, May 5, 1962, 1 speeimen coll. by Mr. Tetsuzo Yasukawa, 25mm; No. 4. Sugashima near Toba, Apr, 20, 1954, 1 specimen coll, by Dr. Manabu Kojima, 18mm; No. 5. Kami-osawa near Wajima, Noto Pen,, Aug. 2,

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102 VENUS:VoL 50, No, 2 (1991)

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Baba ： Anatomy of Phytlodesmium serratum 103

． seve ral specimens coll ． ． mm 1987 ， by Takaoka Biol Club ， 20 （photograph ）；

No ．6．且 ashirimizu near Uraga Tokyo Bay May 22 1989 1specimen coll ． by ， ， ， ，

Miss Keiko Ohkawa ，40 mm （photograph by Ohkawa ）； No ． 7． Locality a．nd

as above − collector ， date May 13， 1990， 3specimens 15 25 mm （a spawn coil

was an aquarium across ． additional − laid in ， 8mm ）． More specimens for observa

tions were collec 七ed from different localities of Japan （detailed Iist omitted ）． − − ∬）escription ： Body length up to 40 mm ， mostly 10 25 mm ． Both the oral

tentacles and rhinophores are slender and simple （rarely 七he latter are wrinkled

on their s urface ）． The foot corners form short horns． The branchial papillae

or cerata are eylindrica1 0ften curved apically and ． the long ， ， deciduou8 They

are set on either side of body in single −rowed arches in the anterior half of

the body and single −rowed simple rows more posteriorly ． The genital orifices

open below the ．fore−arm of first right the arch ， the anus opens in the centre

of the right second arch ， and 七he nephroproct lies in front of this arch ． The

liver diverticulum within the cerata is simple bu 七 it may be ．more or less ，

corrugated when these cerata are contracted ． The cnidosac or the terminal sac ． （Rudman ，1981 ： 245 ） lies close to （in small specimens ）， or rather separated

from （in larger specimens ）， the distal end of the liver diverticulum． The

terminal sae is small and thin −walled without a layer of cnidocysts on the

inner w 乱 1］．

The general integument of the body is yellowish white and translucent ． The

back is more yellowish owing to 七he viscera showing through 、 The upper halves

Fig．1． Phyllodesmium serratum サ ガ ミ ミ ノ ウ ミ ウ シ − − ［A ，G ． Material No ．1 ； B1 3， H ． Material No ．2 ； C ， Ca c ． Material No ．3 ； − D ．Material No ．1supplemented by Material No ．2 （H ． S．）；E ． Fa b． Material No ．4．］ A ．Entire animal from above ，12 mm 全 形 背面 ，体 長 12 mm ； B ． Cerata 鰓 − 突起 （Bl ． when furly extended 充 分 に 伸長 し た 時 ； B2 ． when slightly con tracted 少 し く収 縮 し た 時 ； B3 ． when strongly contracted 強 く収縮 し た 時）； C ．Part量al figure of the contracted ceras and Ca ． Cb to Cc． isolated liver cells forming the liver diverticulum Ca orange cells Cb cell and Cc （ ． ， ．yellowish ， ． 一． colorless cell ） 強 く収 縮 し た 鰓 突 起 部拡 大 （C ）及 び 分 離 され た 肝 盲 管 細 胞 （Ca ． 橙 色 肝 細 胞 ，Cb ．微黄 色 肝 細 胞 ， Cc ．無 色 肝 細 胞）； D 。 Reconstracted internal anatomy of the body from above 体 内 部 解 剖 再構 成 図 背面 よ り ；E ． R 三ght jaw from outside 右 顎 板．外 面 よ り ； F ． Radular teeth 歯舌 の 歯 （Fa ． a tooth from ． above 歯 の 上 面 よ り ； Fb ． a tooth from lateral side 歯 の 側 面 よ り）；G ． General − anatomy of the genital system frQm above 生 殖 器 系 背 面 よ り ； H ． Reconstra cted anatomy of the genital syste 皿 from above 生殖 器 系 解 剖 再 構 成 図 背面 よ り．

Letters 言己号 ： a ．anus 肛 門 ；am ． ampulla 貯 精 部 ；d 。 denticles小 歯列 ； fg． female gland mass 雌 性 付 属 腺 部 ； fo ． female orifice 雌 性 孔 ； go ． genital ori 丘ce 生殖 門 ； hd ． herma 一 phrodite duct 両 性 生殖 輸 管 ； k ．kidney （renal system ）腎 （排 出系）； L1 ． right liver 右 肝 ；L2 ． left anterior liver左前 肝 ；L3 ． Ieft posterior liver ．左 後肝 ；mg ． mucous glands 粘 液 腺 lmo ． male orifice 雄性 孔 ； n ． nephroproct 腎 門 ； o ▼ ． oviduct 輸 卵 管 ； p ． penis ． ． 陰 茎 ； pr ． prostate 前 立 腺 ； sc ． terminal sac 末 端 嚢 ； sg ． salivary gland 唾 腺 ； t． sper matheca （black pigmented ） 受 精 嚢 （黒 染 ）； ▼ ． vagina 膣 ； w ． opaque white 蛋 自 色 ．

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104 VENUS: Vol, 50, No.2(1991)

of the oral tentacles, rhinophores and cerata are densely pigmerited with opaque

white. There is a median white band running from the head to the tail. The

liver diverticula within the cerata are rose, pink or orange red. Under certain

light, the overall white-pigmented integument of the body may appear to be

bluish white. The isolated liver cells consist of orange eells, yellowish cells and

colorless cells, and the first-named cells are the most abundant. Zooxanthellae

are absent from the liver diverticula.

The liver system consists of a right liver, a left anterior liver, and a left posteTior liver. The kidney is mueh branehed. The jaw-plate is sinuated behind. The masticatory edge of the jaw has a single row of about 10 small denticles.

The radular formula is 15 × O.1.0. Eaeh tooth is V-shaped with a row of 25-30

minute denticles or serrations on both edges of the eusp. The genitalia have a single spermatheea. The vas deferens is prostatic. The penis is unarmed. Rema-rks: In the genus Phyllodes7niam (s.1.), the species PL serrattcm is

strueturally one of the simplest. Namely, (1) the eerata are cylindrical, and smooth, not nodu]ose, on the outer surfaee, nor they flattened; (2) the liver

diverticulum within the cerata is simple, not branehed, and not aceommodating

symbiotic zooxanthellae; and (3) the denticles on the jaw-eclge are small in size. Phyllodesmium horriclum (Maenae, 1954a) from S. Africa is similar in body- colors to P. serratum. Aecording to Macnae (1954a) and Rudman (1991), the

two speeies are sepa[rable from each other by some differences of eharacters in

reference to the coloring of the cerata and the radular morphelogy. The occurrence of P. serratum in Australia is demonstrated by Rudman (1991: 170-175).

Quite recently (1990), Miss K. Ohkawa reported that in Fukaura, Aomori

Pref., and Hashiri-mizu near Uraga, Tokyo Bay, the animals of Phylloelesmium

serratum were found feeding on co]onies of the aleyonarian, CornztlaTia sp.

and she saw that the terminal sac of the cerata of the aeolid was separated from

the distal end of the liver diverticulum. Fortunately, she gave me the opportunity

to examine fresh specimens (Material No. 7) of P. serratum, together with a bit

of the feod alcyenarian. The nudibranchs were kept alive in a vessel, and some

of her observations could be eonfirmed. The polyps of the aleyenarian were

orange, and destitute of zooxanthellae. These eireumstanees rnay account, to a certain extent, for the orange color of the aeolid (Ohkawa, 1990), and the

absence of zooxanthellae from the liver system of the aeolid.

Acknowtedgements:-I am grateful to Dr. R.C. Willan (Department of Zoology, the University of Queensland, Australia) and Dr. G. McDonald (Joseph M. Long MaTine Laboratory, the University of CalifoTnia, America) for kindly giving me adviees for

my manuseript. Also I am grateful to the many Japanese friends who generously

helped rne in various ways during the eouTse of this study.

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Baba ： Anatomy of phyllodesmium serrat ” m 105

要 約

サ ガ ミ ミ ノ ウ ミ ウ シ Phyllodesminm serratum （Baba ，1949） は 体 長最 大 40 mm ，普 通 は 10〜25

＝ ミ ノ 一 mln 。 外 形 ．L の 特 長 と し て 背 側 縁 の 鰓 突 起 突起 は 細 長 で ， 単 な 円 柱 状 を 呈 し ，脱落性 で ，偏

こ い 口 ・ 一 圧 す る と な く ，先 端 部 は 彎 曲 し や す 。 触 手 触 角 共 に 単 ， 足 隅 は 短 角状 。 全 体 部 地 色 は 黄 白

は の た め 口 ・ ・ の 色 ，背 部 内 臓 透 見 黄 色強 くな る 。 触 手 触 角 鰓 突 起等 そ れ ぞ れ 上 半部 は 蛋 自色 。 背中

線 一L に は 1 条 の 蛋 白 色 縦 帯 が あ る 。 全 体 部 は 光 線 の ぐあ い で ，青 白 色 に 見 え る 。鰓 突 起 の 中 脈 （肝 盲

の 管 ） は 燈 赤 色 。 顎 板 縁 は 少 数 小 歯 を 生 じ る 。歯 式 は 15× 0．1．0．各歯 は V 字 状 ， ．1噛 尖 の 両側 に は

． ニ 各側多数 の 小 鋸 歯 を 配 列 し ， こ れ に よ っ て ク セ ア ウ ミ ウ シ 属 く広 義） Phyllodesmium （S ，L） 中 に 編

ノ シ ・ ン ゴ の ノ・ ゴ 入 され た 。 サ ガ ミ ミ ウ ミ ウ は 腔 腸 動 物 八 放 サ 虫類 ナ ケ Cornularia sp ． を 摂 食 す る

い と う （人 川 1990）。

References

Baba 1949 ． 額 εん‘め γ α π o ん｛α mi B collecte ・ ，K ， Op o ／Sag α α y ， 〔i by his M α ブθ9 古〃 the Empe ror

o Japa n・ 194 50 Iwanami ／ ． pp ．， pls ． Shoten ， Tokyo ． ． ．1955 んobranchin o ，α mi α collecte （ 皿 α esty Baba ，K ． Opist ／Sa g B y Supplement ， 1 by his ブ ’− the inl’ ，e7 07 o 」α α ％ 59 20 皿 E ノ p ． pp り pls ． Iwanami Shote ， Tokyo ．

‘‘ Baba ， K ．1990 ． Nomenclatural review of the species treated in Opisthobranchia of

，， Sagami Bay （1949 ）． In ； Opisthobr α nchia o ／ S α ga ．mi 召 卿 colleeteal by 雇 8 ’ ” 1Va ・esty tんθ mpeo or o 」α 丿α n edition 13PP ゴ E ノ 2 ． Second ． 211 十 ．， 50 Pls ． Iwanami

Shoten ， Tokyo ．

Macnae ， W ．1954a ． On some eolidacean nudibranehiate molluscs from South Africa ．

且 nn ．ヱ〉 α ・tal ．13 1 ： 1− ．1− ， Mus ， （ ） 50 ， pls 2

Macnae ， W ．1954b ， On 七he status of the generic names of the nudibranch genera ・ ． Ca ・tγ ion α CT α tena − Hervi α Rizzolia and Trinc んes iα Proc α lac Lond ， ， ， ． ．M ．Soc ． ．， − 31 （2 ）： 52 55 ．

，1958 ． wes 七ern opis 七 七ropods ． 。 ． ． Marcus ， Er On Atlantic hobranchiate gas 4mer Mws

・v 壱ta・tes 1906 ： 1−82 No ， （ ） ．

observations on cerata of aeolid nudibranch Ohkawa ， K l990 ． Mo 叩 hological the 響 仞 ？ α ． A note Rep ． Fzakater α M α r ． Biol ． L α b ． （Phyltodesmi m ser tum ） preliminary ． ， − （13 ）： 3 10 ． （In Japanese ）

− Facelinacea 七 七ematic − Risso Dominguez ， C ．J．1964 ． Notes on the ． IL On he sys posi ・ F α （諏 s ］M［ 1954 tion of Hervia ser7 α 亡α Baba ， 1949 and vorinus horri acnae ， ． ． BetX．Zt rti ，a 10 128 ： 222 −238 ． ．fo ， （ ）

Rudman W ． R 1981 ． The anatomy and biology of alcyonarian −feeding aeolid 《） − ， pistho

branch molluscs and their development of symbiosis with zooxanthellae ． Zoo 乙 」．

72 3 219 − Liwnt．Soc ．， （ ）： 262 ． − Rudman ， W ． B ，1991 。 Further studies on the taxonomy and biology of the octocoral

feeding PhylloofeswLizcm Ehrenberg 1831 Nudibranchia ： 」 genus ， （ AeolidQidea ）． ． − Mol1 ． S七ud ．，57 （2）： 167 203．

Received ： 〕ruary 20 19911 ［ Fel ，

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106 ： VENUS Vo1．50， No ．2 （1991）

Plate l 1 PhyUodesmium serratum

サ ガ ミ ミ ノ ウ ミ ウ シ Material No ．5

2 phyUedesmium serratum feeding on Cornuta 「ia sP ．

ハ ナ ゴ ケ 摂 食 中 の サ ガ ミ ミ ノ ウ ミ ウ シ Material No ．6

（Photo by K ． Ohkawa ）

3 Phyllodesmium serratum ， a spawn coil

サ ガ ミ ミ ノ ウ ミ ウ シ 産 出 卵 Material No ．7

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Baba: Anatomyof Phyllodesmium serrat"m 107

Plate 1

1

2

3

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