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"ec VENUS (Jap. Jour. Malac.) Vol. 49, No. 1 (19901}:45-53

fi v if' i F} 3 llENoJE;ue ･ tsme t ERifi eeO

ee is,E tzc ou t 6 re "n bl 3

ff,i N ,de.-, EIEF

Further Studies on the Strueture of Osphradiurn in

Three Subfamilies of Natieidae with Reference

to their MorphologsT and Eeology

/ Toyohide MAEDA (Laboratory of Sea-Farming, Tokyo UniveTsity of Fisheries, 4-5-7, Konan, Minato-ku, Tokyo, 108)

Abstract: The numbers of leaflets and structure of the osphradium of 20

species of three subfamilies of Natiaidae, viz. Natieinae, Polinieinae and

Sininae, were examined in relation to shel] form and size. The numbers of

]eaflets in the Polinicinae is eonsistent]y small (50-80) throughout a varied

range of sizes of animal (10-60mm in shell length). All of the Polinieinae

under examination except Lunatia are hemispherieal in shell shape and have

strueturally eomp]ieated osphTadium. The Natieinae are spherical in she]1 shape and have an osphradium of simpler strueture with numbers of leafiets

seemingly increasing with shell size, In Crypto7zatica wakkanaiensis the

numbers of the leaflet are most numerous attaining up to 170, Lunatia has

the shell of spherical form and pessesses the simple osphradium with about 50

leaflets. This may mean Ltmatia stands a transitional situation between the Naticinae and the Polinieinae. Sinu?n･ o'avaniettm has a depressed shell and

complieated structure with 50 leaflets, Complicated osphradium is consistently found in speeies which bury deep in the substratum, while simpler one is

common among speeies which either remain shallowly buried or creep on the

sand. It is thus suggested that the structural complexity of this organ within the Naticidae is related tQ the mode of life, particularly degree or depth of burrowing into the soft substratum.

Introduction

Maeda (1983, 1986, 1988, 1989) described structures of osphradia in re-

lation to the differenees in shell form, soft bodies as well as in habitat among

the prosobranch family Naticidae. In these papers only 7 species were treated, 1 The present investigation on the numbers of ]eaflets and the morphology of

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46 VENUS: Vol. 49, No.1(1990)

the osphradium was extended over more speeies of the same family in order to

eorroborate the previous results and to throw the new light on eeological and

evolutional bearings of osphradian struetures.

Materials and Methods

The present materials consist of 20 species of three subfamilies, viz. 'the Naticinae (7 species), Polinicinae (12 speeies) and Sininae (1 speeies) of

family Natieidae:

Natieinae: Cryptonatiea o'anthostomoides (Kuroda & Habe, 1941)

C. ctausiformis (Broderip & Sowerby, 1829)

C. zenr-yumaruae Habe & Ito, 1976

C. o'anthosthoma (Deshayes, 1841)

C. tvakhanaiensis Habe & Ito, 1976

C. russa (Gould, 1859) C. hirasei (Pilsbry, 1905)

Polinicinae: Lunatia foTtunei (Reev6, 1865) L. pli$ipara Kuroda, 1961

L. pila (Pislbry, 1911) Polinices mellosms (Hedley, 1924) P. tzamidus (Swainson, 1840)

Table 1.. Locality,habitat and shell size of examinedT.se.ecies, -. .

Species N Locality Habitat*Length × width

Lunatia Pila 11l19533311196226814621Akkeshi s 3,5 × 3,5 L. PlicisPira Cape Soya s 2,2 × 2.1

L. fortunei Ariake Bay M 2.8 × 2.8

Pblinices mellosus Philippines s 2.0x2,6

PL tumidus Philippines sM+S 2.1× 2.2

P. sagemiensis Mikawa Bay 3. 5 × 4, 1

R vestitus Mikawa Bay s 3.5 × 4,5

Mlammiila oPaca Philippines s 2.2× 2.6

M. mihawaensis Mikawa Bay s

Glossaulax reiniana Mikawa Bay s 4. 5 × 4, 1

G. didyma Mikawa Bay s 4.5 × 5,5

G. vesicalis Mikawa Bay s 3,5 × 4,2

CrNPtonatica janthostomoides Ch6shiWakkanai s 3,6 × 3.7

C. etausijbrmis s 2,4x2.4

C. xenryumaruae KushiroHakodate sM+S 5,OX4,5

C. russa 4,5 × 4,5

C. wakkanaiensis Wakkanai s 7.0× 6,9

C. hirasei Kushiro s L7 × L7

C. jonthostoma KushiroMikawa s 4.8 × 4.7 Sinum tiavanicum Bay s

* M:mud;S:sand

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Maeda: Further Studies on Naticid Osphradium 47

A sagamiensis (?ilsbry, 1904J

P. vestitus Kuroda, 1961

Mammilla opaca (Lamarck, 1816)

M. mikawaensis Azuma, 1961

Gtossaulas didyma (R6ding, 1798) G. ren'niana (Dunker, 1877) G. vesicatas (Philippi, 1894)

Sininae: Sinum jovanicum (Grirnth & Pidgeon, 1894) Shell length and width were measured with calipers after a careful observa-

tion of the shell rnorphology. The she]1 was then crushed to open and the

soft body was removed and fixed in a 10% neutral formalin. Dissection and

preliminary observations of the osphradium were carried out under a dissecting

microseope. Osphradia were ]ater dehydrated in ascending alcehol series,

ernbedded in Paraplast, and sectioned and stained with haematoxylin-eosin.

Mean number of leaflebs was counted and standard deviation was calculated

except in cases where number of specimens was Iess than three per species.

Number of species examined, locality, size (shell width and length) and shell

form are shown in Table 1.

Table 2, Morphology of osphradium and shell forrn of Naticidae examined.

of Species Type*Numbers osphradial leafietsStructure**Shellform***

Lunatia Pita llllll[llllllllll[llullllllllullllfi54,6 ± 5.1 sssccCcCCCCCssssssss

L. PticisPira 51, 554, sp L. fbrtunei O66. } Pbtinices metXosus 2± 3, 7

P. tumidus 66,4 ± 6,4

P. sagnmiensis 65,354. lHS R vestitus 780.

Mammilla oPaca 156. ML mihawaensis 045, f Glossaulax reniana O73.9 spHS

G. didyma ± 6.7 G. vesicatis 65.8± 4.2 } CrsPtonatica 1'anthostomoides 109.4± 9,2 C. clausinrmis 79. 8± Z3

C. 2enryzamaruae 96.4± 6.8

C. russa 85,O146, sp

C. wakkanaiensis 7 ± 16. 4

C. hirasei 59. 0 ± 7, 1

C. janthostoma 85,O D Sinum iavanicum 55,O

"simple "cornplicated"; **** *' Type adepted by Maeda ; S denotes and C, L

"depressed",(1988) "hemispherical" D indicates HS, and SP,ttlcspherical".

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48 VENUS: Vol. 49, No. 1 (1990)

50 1OO 150

Lunatiapila

L.Pticis'pita

L.fortunei e Potinicestnetlt)sus it' l'.t"mid"s -.-4F.

P-sagamiensis 7]g P.vestitu.s lee Mammiltaopaca I e M.mikawaensis e Glos.sa"taxreiniana e (i.didyin(t + G'.vesicati,s' . Cryptonaticayanthosromvides

C.ctausiformis ]1 ' 1 c.renry"maruae l1 C,r"ssa l1 e C.wakkanaiensis I ' C.hirasei

C.janfhostoma e Sin"mjavanicum e

Fig. 1. Number of osphradial Ieaflets by species. ptlcliggstXdheeX diegem

Horizontal bars indicate the range of variabilities, Circles show

the mean value, otherwise real count when less than 3 specirnens

were available.

Results

Shells of al! species of the Polinicinae except Lunatia are hemispherical.

The shell of both L. rortunei and L. ptla is like a viviparid. The Natieinae

have a spherieal, while the Sininae have a depressed shell, Marked differences

in leaflet numbers are observed between the Polinicinae and the Naticinae.

Leaflet numbers are about 50 for Lunatia, 60-70 for Polinices, and 70-80 for

both Mammilla and Glossaulax (Fig. 1). It can be seen that leafiet numbers of

the Polinicinae consistently fall within a narrow range between 50 and 80

for shell width of 10-60mm regardless by species (Fig. 2). On the contrary,

the number of leafiets of 7 species of the Naticinae greatly varied from 50

to 170, even though among a single genus Crytonuttica. C. hirasei has the

lowest number of ]eaflets (50) for shell width of 15-20mm, while the largest number of leaflets (about 170) are found in C. waichauaiensis (Fig. 3). The

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Maeda: Further Studies on Naticid Osphradium 49

number of leafiets in the Naticinae seems to increase with shell size almest in a

linear fashion (Fig. 3). Sintem 2'avanicum, the only species ef the Sininae under examination presents about 50 leafiets.

Histo]ogical observations on sectioned specimens of the osphradia revealed

that simple structure is found in Lunatia fortunei and L. plieisptra (Pl. 1, fig. 1) while more complicated one in L. ptla. All other Polinicinae pessess

osphradia with complicated structure. This can be notably seen in P. tumidus

(Pl. 1, fig. 5) and P. mellosus (PL 1, fig. 4) despite their small shell width

(abeut 20mm). Structurally, Mamwitla (PL 1, fig. 6) and Glossaulax are the

most eomplex. Sueh comp]ieated structure is also observed in the Sininae, while

all Naticinae examined have a relatively simple structure (Pl. 1, figs. 2, 3).

Discussion

There may be two ways of improving the olfactory function among Gastro- poda. One is through an increase in the number of sensory eells and the other

m-o=ero-

100 -N--vcaL=acoo MammiUat'-s ' " t.`.,.fog)/i'v"`lillii v '

,,..,.. 5 50 ts--=. l!!)cl' potinices:N.l'kLss).:..I!..).:.:-:tS'!:'l Lunatia 9oDE=z ' -t ttt t t t '

o lo 2o 3o 4e so 6o 7o

Shell width (mm)

Fig. 2. Relation between shell width and numbers of osphradial leaflets in the

Polinicinae. F q ij'ldiI:･ftctstl]'6ueas8ggeXtixeeXomaes

e L"natia Pila; Li Mitmmila oPaca; A M. mihawaensis; O Pblinices tumidus; @ P. mellosus; V GIossaulax vesicalis; - G. didyma

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50 VENUS:Vol.49, No. 1 (1990)

200

'-. sN

--Xx t N x tl- ' 1 50co- 1 -l l ! xl ¢ ! =er2-esb-N10O=a8 vv × 1 1 1 vv l 1 IZv9VV7vvve 111

1 VOl l e o/ x e z !l-- 1xe AY

-o l e t - 1A -- t - 9 5oODE=z TA /- N .t N t---p

O 10 20 30 40 5D 60 7D 80

Shell length (mm)

Fig. 3. Relation between shell length and numbers of osphradial leaflets in Cr)ptonatica. CrJ¢ )tonatica MOpt a' t Outft k wawt234liecX t O ma es V Cr)f,tonatica 1'anthostomoides; e C. etausiformis; O C. 2enrptu- maruae; × C. wakhanaiensis; A C, hirasei; D C. russa

is through a qualitative change. The former can be achieved by a) an increase

in the number of osphradial ]eaflets, b) an increase in the width of the leaflets

and c) by increasing the structural complexity of the organ. Qualitative

changes may involve the appearance of new cell types such as Sl, S2 and S4

of Haszprunar (1985). Haszprunar divided Taenioglossa into two groups, the

Archeotaenioglossa and the Neotaenioglossa, based on the presenee of such

new cells. The Naticidae belongs to the latter.

An increase in the number of osphradial }eaflets is observed in the Naticinae

and also in the Strombidae. For instance, Strombus has an osphradium with

simple structure, but 150 to 300 leaflets (Bernard 1890, Maeda 1986). The

inerease of the width of the osphradium is observed in Tonnoidea and Neogastro-

poda, both of whieh comprise carnivorous species thus require effective olfactory

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Maeda ： Further Studies on Naticid Osphradium 51

organs complex structure （Bernard， 1890 ）． The of the leaflet， as seen in 七he

Polinicinae also skilful ， is found in the Conidae ， both being hunters （Bernard

1890 ，Alexander 1970 ）， The results of the presen七 investigation indicate that an increase in the

number of leaflets seems to be characteristic of the Na 七ieinae while increased ，

complexity of the Iea且et structure is common in 七he Polinicinae， An exception

is Luncvtia which may be a transitional stage between the two subfamilies ．

The differences in osphradium types between the Naticinae and the Polinicinae

were expeeted and seem to be related to their ecology ． The Naticinae genera11y

have a Iess developed propodium and spherical shell ， thus being bet七er able 七〇

creep on the sand than to bury themselves ． Abundan 七 water can therefore be utilized for searching for food （Maeda ， 1988， 1989 ）． On the contrary ， the

a Polinicinae has developed propodium which can cover the hemisphericalshell，

adapting sand ． surrou it to bury into the （Maeda ， 1988 ， 1989 ） The scarce 皿 ding

water available under deep sand must be eMciently used by the osphradium

with struetural complexity which ra 七 compact ， is her yet highly emcient ．These

differences are Iikely independent of size ． G ． didyma ， a large Polinicinae which

buries deep in the sand has hemispherical a shell ， a small mantle cavity ， a ’ zigzaging axon of osphradium ． 0． w aiChanaiensis ， a Iarge Naticinae， has a

spherical shell a ， large mantle cavity with an linear axon ，about 30mm in length． ’ C ． tvakk αu α iensis lives under shallow sand or may be on the sandy bottom．

Similar trend can be observed in the Sininae． 8．ブavanicum has a developed

which covers shelL also under sand propodium ， the depressed It lives the ， has

an osphradium with small number of ］eaflets （about 50 ） but complex structure

Maeda 1988 ． appears an osphradium s 七ructuraI （ ， ） Therefore ， it that increase in complexity within the Na 七icidae is related to life under sand ．

− AcknourSedgements’ The author is grateful to Profs ． Takashi Oku 七ani and Fumio

Takashima （Tokyo University of Fisheries） for valuable suggestions and cons 七ant supPort ・ Thanks are also due to ML Kiyoshi lto （Otaru ）， Mr ． Kinji Takagawa

Rakodate Mr ． Yoshio Kushiro （ ）， Suzuki （ ）， personnel of Hokkaido Wakkanai Fisheries 」 Experimental Sta．tion and personnel of Akashima Mar 童ne Scienee Laboratory （Oki−

nawa ） for making av 訊 ilable the mollusc specimens ．

要 約

先 回 （前 田 ，1989） タ v ガ イ 科 の 3 亜 科 ，す なわ ち タ マ ガ イ 亜 科 ， ト ミ ガ イ 亜 科， フ ク 卩 ガ イ 亜 科

に つ い て ，嗅 検 器 の 構 造 と形 態 及 び 生 態 の 関 連 に つ い て 述 べ た が 今 回 は 更 に 多数 の 標本 を 用 い て 調 査

し タ マ ガ イ ：亜 で は の が つ た 。 科 嗅検 踞 小 葉数 ，殻高 が 高 く な る に れ て 増加 し て 行 くが ，小葉搆 造 は ほ

い マ ツ メ ． と ん ど 変 化 は な 。 タ タ ガ イ 属 以外 の ト ミ ガ イ 亜 科 で は 構 造 が 複雑 化す る の が 特徴 で あ る が小

は て の で 〜 で 一 マ 葉 数 全 属 50 80 台 ，殻 幅が 増 加 し て もほ と ん ど 定 の 値 を 示 す事 が 判 っ た 。又 ， タ ツ メ

タ ガ イ 属 は 殻 型 が タ ニ シ 型 な い し 球 型 で ，小 葉数 が 50台 ，小 葉構造 は 単純 で ，上 記 の 2 亜 科 の う ち で

つ は 原始 的形 態 を 持 と 思 お れ る 。

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52 VENUS ： Vol．49， No ，1 （1990）

ツ メ タ ガ イ は ト ミ ガ イ 亜 科 に 属 す る 大 型種 で あ る が ，半 球 型 の 殻 を 持 ち ，嗅 検 器 の 軸 は 蛇 行 し て お

い ・．．・ タ マ ガ イ り，小 葉構 造 も複 雑 で 砂 中 に 潜 る 際 ，少 な 環 境 水 を 有 効 に 使 用 す る と 思 わ れ る 。 方 ， 亜 一 ・ “ 科 の 最大 型 種， ワ ッ カ ナ イ fi ガ イ で は 殻 が 球 型 で ，外 套腔 が よ り広 い と 思 わ れ 小 葉数 は 170位 で 嗅

の で こ の こ に て ツ メ タ ガ イ 検 器 軸 は 直線 的 ，長 さ は 30mrr1 に も 及 ぶ 。 と は 砂 中 深 く潜 っ 生 活 す る 類

マ の い と，砂底 の 表面 近 くに 生活 す る と思 われ る ワ ッ カ ナ イ タ ガ イ の 生 活 の 場 違 と 思 わ れ る 。

フ 卩 卩 ク ガ イ 亜 科 の フ ク ガ イ は 殻 が 扁 平 で あ る が ，小 葉数 は 50 台 で ，小 葉構 造 は 複 雑 で あ る 。 本 種

い で は 完 全 な 砂 中生 活 を す る が ， 小 葉構 造 の 複 雑化 が 砂 中 生 活 に 関 係 し て る 事 を 示 す 傍 証 と な る あ ろ

う。

References

Alexander C 1970 osphradium of 軅 伽 8 αr ： −240 ， G ． ． The Conus 伽 ，M ，Biol．，6 236 ．

sur organes Bernard ， F ，1890， R6cherches les pallaux des gast6ropodes prosobranches ． − Ann ． Sei， Nat ． Zool ．，7 （9 ）： 84 424 ．

Haszpruner G ．1985 ． The 伽 e morphology of osphradial se 皿 se organ of Mollusca ． ，

1 ： ． 腕 ． TTans ， α 1． ． Lonc 迂ont B 307 ： Part Gastropoda ， prosobranchia P Z Rey Soc 457−496，

Maeda T ．1983． Types of osphradia in the Prosobranchia with special reference to ，

feeding habits 41 ： 264 −273 In Japanese with English relation with ． Venus ， （ abstract ）．

Interrelationnships habitat and food habit Maeda ， T ．1986． of types of osphradium ，

θ 翩 s ； − of Cerithiacea and its near superfamilies （Mesogastropoda ）． y ， 45 31 41．

（In Japanese with English abstract ）． Maeda ， T ．1988 ． The structure of osphradiun of three subfamilies in Naticidae with

reference orphology and ecology θnus 47 ： 121 −126 to their 皿 ． V ， ． （In Japanese

with English abstract ）．

Maeda T ．1989 ， Search and observation of moon shells in Akashima Okinawa Pre− ， ，

fecture ． Chiribot α n （1皿 Japnaese with English al）stract ）．

［Received ： November 6 ，1989 ］

Plate 1． Cross section of osphradia of six species of tne Naticidae．

ーロ Lunatia キ ザ ミ タ マ ツ メ タ ガ イ． （× 40） Plicispira 23456ロ CryPtonatica hirasei ヒ ラ セ タ マ ガ イ x80 （ ） C ．claUSiformis ハ イ イ ロ タ マ ガ イ （x40 ）

ロ Polinices tumidus ト ミ ガ イ （× 80）

ロ P ．metlosus ロ ウ イ ロ ト ミ ガ イ （× 40） ・ サ Mammizaa oPaca リ ス ガ イ （x40 ）

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MaedaFurther Studies on Naticid Osphradium 53Plabe

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