120 T. SflIKAMA
Palaeogene Miocene Pliocene･pl
eisto･
ene HoIQCelle
EarlyMid.Late lEarly LateC
nJ〇
tT]勺u7]c7トニ 冒 E‑EJ く̲̲1 Fミ読
小Ot畑〜
‑一ー
■‑一
̲‑一一
′ ノ:
′
′
′
′
′′/′
l勺
!=
■･･･‑
Uq く⊃
ト1
コ.
P3
トセ
∽ rつ 'O
∫ PL) (■つ P upestris
LLr＋＋i
〜1bO8￠Sr
乞alm(社交
h.St
h.
■h 1C
fI.A."
niPPonhaiensis
‑i̲olsaensisし＼､ヾヾ
̲‑‑ll‑‑I‑‑‑‑‑一‑‑ exoptanda
■‑I megaipilra
′′′
//′
′′■
′
′
′
′
′
′′si†tZletlS
′
′
′
Ire
l
111amOtOi
l
kd由eko tlLI
IL
k.hayashii
ll
co71CtTL71a
C
C
I.C･t]L
HILl If111
.corrtLgata
ttL=l
Il IIIl
I
lll5WB沖 一■ J■
′■■
′一′J一‑‑
一′一一‑̲‑‑
Ill lC.rOSea
LIld i'iesillLL llLtLHLl
I a
‑‑一‑‑
.･:̲･二･I==;i:･
/I一‑￣
′■
∫
ノ′‑I‑
′
t￠ssettlata̲I‑‑‑‑
一■■
′￣
■‑一■
′■
̲̲excelsa
masudae
･1z
宅
○
IJ
⊂) コ
■̲I
(つ く⊃
i.･･angulosa･‑i;':A:､i･'･了{･､;::〜.･▲･
̲̲一一‑￣･:言,.･Otukail･̀i
ー一‑‑ー
‑J‑4
̲‑I‑一一‑‑‑‑
.･.･.†.,さ∴1.L:■◆1̲.
′､1､､･.甜志豊,I:1i,=T.,き三芸≡三笠1:e
■=r‑
'･:Ll:.
1=:='l:lil
'l･'/･l･tご･丁こT!LI'1.1LISl:T:L〜･
◆14▲■■▲●ヽ
●●.‑I
･､さI'̲
･:J41■･./11I>':･
..A:L::;..::.:l･;:･墓i･･.:‑fi=:l･:I:LL;::.:〜:;i‑濡･i'tT:'t･'.･31･7t::L･L芯.::';･L
L ▲■‑;f二こ7i:...T註首i'{el;os▲●■l a:.:.I,･暮′1て‑ニ1.i.i恐i･li:::.1':.‑TLt.･L'ヽ･.A.L･.J･t.yt:*.斗●･一･‑･･土･上い
''‥ゝ'i､こ>':'LLr.言f:''言･S:fさ芸;:I:I:?i;iqi･‑I
oz.:,:;･･･Ti‑.､t.L･.･･･;L{･d･.､･{.･･..I.I.,LI
･･･L･::.･････:I.I‑‑‑‑,････.̀一･=7碧く'e々
‑'･‑.･..tて.‑f･､.I.‑.‑I.I‑ ■いIL I‑･■･/?.･､⊥(.1b●
A‑,･.
.'ヽ l､■●▲■■▲l
I:1･Lt:.t1.̲‑I:〜(･'?‑.̲･h?.I..1'J,b‑i上■‑
i./ujl'mo(
ヽ●●ヽ
J､
‑･,･一･'‑kT'1tl･.'･'･.:･p･salebros
∫z･i･:･';:･･::･t!･脅FIL.!il ･.･..･一､.1･..T.ー
‑?‑I7, A̲･3(2
.･.i;=if.::f迂ii;･
=T:.:i.:･:･;‑=･･b‑i2!e!,?I.';TE;I;:･･
%D/9!b!2e
/e4kzふ
ち
〜
＼q々/;
＼4,eoAseA
System and Evolution of Japanese Fulgorarid Gastropoda
Table 37･ Age distribution of recent species and subspecies.
121
Holocene K
Pleistocene
∫ I
Pliocene Miocene Oligocene
Fulgoraria Psephaea Nipponomelon Musashia Saotomea Total
6 9 6 5 1 27
1 (1)
3 (3)
5 (6)
4 (4)
1 (1)
14 (15)
H2 1 (1)
2 (4)
5 (7)
4 (5)
1 (1) 13(18)
Ⅱ1 1 (2)
2 (4)
3 (5)
2 (6)
1 (1) 9(14)
0
G i F3
0
F卜2
0 0
E D C
0 0 (2)
3 (5)
1 (4)
0 (0) 4(ll)
0 (3)
2 (6)
1 (4)
0 (0) 3(13)
0 (3)
1 (5)
1 (3)
0 (0) 2(10)
0 (2)
0 (4)
0 (2)
o
(o)
0 (8)
0 0
(1 (3 (3 ) ) )
0 (1)
0 (0)
0 (8)
Total speci丘c number in each stage in parenthesis.
Table 38･ Percentage of recent species to total species.
Holocene Pleistocene Pliocene
.Miocene Oligocene
K JI H2Hl
､耳吾l16i㌃
DCFulgoraria 100 100 10050 0%
Psephaea 100 100 5050 0000 0
Nipponomelon 100 83 7160 6033200 0
Musashia 100 100 8033 25′25330 0
Saotomea 100 100 100100 0000 0
Totalmean 100 97 8059 1712110 0
for the evolution of fulgorarids in Japan.
B. Acceleration
As indicated by the modernization curve of subgenus in text丘g. 23, mod‑
ernization was accelerated since early Pliocene･ As far as it is concerned, phylogenetic evolution of the Japanese fulgoraris is arranged in three stages
as follows.
Early stage: Palaeogene to earliest Miocene
(C‑E).
No recent species appeared in this stage.Middle stage: Miocene
(Fl‑G)･
There appeared some recent species.Percentage of recent species to total ones is below 27% on an average.
Late stage: Pliocene to recent
(Hl‑K).
Recent species increased.￣per･
centage of recent species to total ones is over 59% on an average. Modern‑
ization was highly accelerated.
The total number of species and subspecies of the norther･n fulgorarids
122 T. SHIKAMA
in each stage is shown in Table 39･ The number of species increases abruptly since Pliocene
(HrK)
but the percentage of subspecies to species abruptly increases since late Miocene(G‑K).
Subspecies are all established upon the recent species, and little is known on the extinct species･ Be that as it mayG stage presents an important moment for the fulgorarid evolution during
the middle to late stages.
Table 39. Total Number of species and subspecies in each stage.
C‑D E Fト2 F3 G Hl H2 トJ a
Species 12 10 12 12 9 17 16 12 19
Subspecies 0 0
0
0 1 2 2 2
13
3 3
Percentageofsub･
speciestospecies
0 0 8 22 12 25 42%
Table 40. Generic and specific numbers and their potential coeBicient.
Generic number*
Speci丘c number*
Potential coe庁icient of genera
Ditto of species
D 6 6＋6
7
45 E 6＋0 7＋3
1
33
Fl̲2 6十0 8＋4
30
F3 6＋0 11＋1
1
26
5＋0 6＋3
1
25 Bl 5＋1 7＋1
22 H2 5＋0 12＋4
12
トJ 5＋0 12＋0
0
5＋0 11＋8
0
8
* The number of those already appeared is on the left side and that of newly appeared on the right side.
Since Oligocene
(C)
to recent, fulgorarid discharged 45 species, of which 19 are recent and 26 are extinct, hence their total potential energy of taxa is indicated by coefBcient 45; in basal Miocene (E) 12 species were discharged and their potential energy of taxa is indicated by coefBcient 33, thus in recent(K)
itis 8(or
8＋Ⅹ). Generic potentiality ab‑ruptly decreased in E stage, while speci負c potentiality decreased graduallythroughout
Miocene, and decreasedwith a relatively
highspeed
since late Pliocene(Hl).
Rate of speci丘c appear‑ance per 106 years is shown in Table 41, that is, highest in E stage, next in
D and HI Stages and very low in Fl‑G stages. From these points of view,
Pleistocene is inslgnificant, but when Pleistocene and recent are treated as a single age, the value becomes 3.8 which is rather high. Basal
MioceneしE)
isvery slgniBcant owing to the abrupt decrease of generic potentiality and
highest rate of speci丘c orlglnation.
Systeln and Evolution of Japanese Fulgorarid Gastropoda 123
40
つ0.‑
C‑D 亡 Fl F2 F3 G Hl H2 IJ K
lw
50
2o
一〆 / / /..･･･''
′ーー
h････‑.･‑･''
/′
JJ
■′
■■
/
..<･‑･J'ー●‑̲̲
′○'･L･‑･￣･●
/ .//
/
/
/
/
‑○イ▲･.∫
∫
/..L'L
I,･L
I
ア /
I
,/I /
.{' ーーq',I
∫:/
̀L&/
‑;･･Zl
○
･･/;(.･･
jo'I
i
○
2
IO,
J･.血拶
Fulgoraria ‑
‑‑
‑ ‑‑ Musashia O‑O Total speci丘c num‑bers
PsePhaea ‑ ‑一‑
‑ Saotomea ●‑● speci丘c potential curve
NiPPonomelon
Text丘g･ 23･ Modernization curve of each subgenus shown in the upper chart.
The numbers of vertical line show percantages･ Speci丘c potential curve of the
northern fulgorarids shown in the lower chart.
Table 41･ Rate sf speci丘c origination par 106 years.
D E Fト2 F8 G Hl H2 IIJ K
TimelO6years 2.4 0.5 5.3 4.･4
0.2
5.4
0.6
4.0■
2.5
4.0 2.0
0
0.1＋
? RateofspeciBc
aPPearanCePer 106years
2.5 6 0.8 1
1.6 3二8
C. Distribution
Geograpbical distribution of recent fulgorarids in
Japan
is shown in textfig･ 24 and its range of latitude is町shown in text丘g･ 25･ Each genuslhas
the following ranges. J音
Fulgoraria : Lat. 22o‑37oN.
PsePhaea: Lat. 24o? 27o‑39oN.
124 T. SHIKAMA
Nipponomelon: Lat･ 33o‑45oN･
Musashia: Lat. 33o‑35Q30'N. 〜 saotomea: Lat. 31o‑34o30'N.
If the area of Japan Sea is excluded, the northern limit of Fulgoraria is Lat･
34oN and that of PsePhaea is Lat. 35o30'N, which are generauy included within the area of the Kuroshio current. The southern limit of Nipponomelon and Musashia is Lat. 33oN, generally corresponding with the northern area of the Kuroshio current. Musashia and Saotomea are restricted in central Japan of paci丘c water^and Nipponomelon extends into the area of the Oyashio current･
1200
･400
l･30o(4CB
JS
○
S q9