Tải bản đầy đủ - 0 (trang)
Chapter 54. The provincial distribution of shallow-water Indo- Pacific marine Ostracoda: Origins, antiquity, dispersal routes and mechanisms

Chapter 54. The provincial distribution of shallow-water Indo- Pacific marine Ostracoda: Origins, antiquity, dispersal routes and mechanisms

Tải bản đầy đủ - 0trang

760 S. TITTERTON

AND R. C. WHATLEY



One of the objects of the study of the Solomon Islands fauna was to attempt to determine its

origins and closest affinities. To this end, all published literature on Tertiary to Recent Ostracods

from the Indo-Pacific and adjacent southern ocean has been analysed. This includes studies from

adjacent coastal areas such as East Africa and the Western seaboard of North and South America,

etc. Since the study of the Solomon Islands fauna was restricted to the Podocopid and Platycopina,

only data on these groups is presented here. For similar reasons, only data on littoral and shelf

species is included.

The number of papers analysed was 285 and the study is up to date to April 1985. A total of 2599

species were recorded and their geological and geographical distribution noted. Space precludes the

listing of the various species here. They can be found in Titterton (1984 MS.).The present study,

therefore, is based on a numerical analysis of the species.

Although we encountered some species which are very widespread geographically and fairly

long ranging, the vast majority are very restricted both geographically and in time. Approximately

70% of the species are recorded only from very limited geographical areas.



TEXT-FIG.

1-Map showing the 13 zoogeographical provinces in the Indo-Pacific region, based on Ostracoda.



Provincial Distribution of Shallow Water Indo-Pacific Marine Ostracoda 761



THEPROVINCIAL DISTRIBUTION

OF SHALLOW

WATERINDO-PACIFIC

OSTRACODA

Compared to our knowledge of the Tertiary to Recent ostracoda of Europe and North America,

we know relatively little of Indo-Pacific faunas. Although studies in the region began as early as

1850, only 85papersonfossil and Recent ostracods were published prior to 1945. Since that date,

approximately 200 papers have been written, reflecting the growing interest in this extensive region.

Many of these works have been concerned with faunas of a limited area. The faunas of some areas

within the Indo-Pacific are relatively well known; viz Japan, the west coast of North America and,

to a lesser extent, Australia, Indonesia and South Africa. However, large areas have been substantially neglected, particularly the Pacific Islands and the northwestern coast of South America.

Subsequent studies in these and other areas may alter some of the details of the present study, but

the major features are not likely to change.

The reasons for endemism are well known being principally due to physical barriers. Latitude

and the deep oceans are the principal barriers to the distribution of Indo-Pacific shallow water

ostracods. In the present study, the Ostracoda of the Indo-Pacific fall into 13 zoogeographical

provinces. These vary considerably in the geographical areas they encompass and in the total

number of species recorded from them (Table 3). Those taxa which typify the various provinces are

given in Titterton (1984 MS.)and will be eventually published elsewhere. Space requirements

preclude their inclusion here. The 13 provinces are shown in Text-fig. 1.

Although Benson’s (1964) paper on the provincial distribution of the Pacific has been considered,

the Pacific provinces proposed in the present study are not based on this work. Benson recognized

11 realms in the Pacific. He comments (p. 3880, that “The effects of temperature, salinity, bottom

sediment, depth, and immigration history are strongly suggested within the distribution of the

465 species thus far identified or described”. The present study concentrates on the immigrant

history of the various faunas in an attempt to elucidate the origins of the Recent Indo-Pacific

Ostracoda as a whole.,



A SYNPOSIS

OF THE NATURE

OF THE 13 PROVINCES

The following observations have been made on the provinciality of the faunas of the various

provinces and of the degree of affinity between provinces.

The Recent marine fauna of the Eastern African Province (Province A) is comparatively poorly

known, the most extensive work being by Hartmann (1974). Other authors have studied species

from 1 or 2 localities or have concentrated on a single taxonomic group from scattered localities.

A total of 221 species have been recorded from this province. The provinciality of the fauna of this

province is relatively poor (Text-fig. 2a). The fauna shows strongest affinity with that of the Southern and Southwestern Pacific (Province H), with 19 common species. The fauna also shows

strong affinities with that of the Australian Province (Province F) with 13 species being common.

However, no species were common with the Western North and Central American Province

(ProvinceJ).

The provinciality of the fauna of the Arabian province (Province B) is strong; however, relatively

few species (146) have been recorded from this region and the ostracods have not been comprehensively studied (Text-fig. 2b). The fauna displays strongest affinity with that of the East Indian (Province Da), 16 species being common to both. No species are common with Provinces B and Db

(Khymerian).

Similarly, the Recent faunas of the Bengalian Province (Province C) are poorly known, the



A N D R. c. WHATLEY

762 S. TITTERTON



TEXT-FIG.2-Link diagrams illustrating the number of endemic species and number of species common with

other provinces for four zoogeographical provinces. 2a, East African Province; 2b, Arabian Province;

2c, Bengalian Province; 2d, East Indian Province.



TEJCT-FIG.3-Link diagrams illustrating the number of endemic species and number of species common with

other provinces for four zoogeographical provinces. 3a, Kymerian Province; 3b, Japanese Province;

3c, Australian Province; 3d, New Zealand Province.



Provincial Distribution of Shallow Water Indo-Pacific Marine Ostracoda 763



majority of the 157 species being recorded by Brady (1866) and Scott (1905) from around Ceylon.

The fauna of this province shows a comparatively strong connection with that of the East Indian

(ProvinceDa) with 23 species common and the Southern and Southwestern Pacific (Province H)

with 24 common species (Text-fig. 2c).

The Neogene and Recent faunas of the East Indian Province (Province Da) are comparatively

well documented. The provinciality of the fauna is poor; only 126 species of the 302 recorded in

this province are endemic. The fauna displays strongest links with that of the Southern and Southwestern Pacific (Province H) as 40 species have been recorded in both (Text-fig. 2d). Affinity is also

strong with the fauna of the Bengalian (Province C) with 23 common species, Australian (Province

F) with 26 common species and the Khymerian (Province Db) with 10 common species.

The study by Kingma (1948) paved the way for the re-evaluation of the taxonomy of the ostracods of the Indo-Pacific. This work has been continued more recently in this region by Keij (19661979) and two further studies are currently being undertaken at Aberystwyth.

The majority of work in the Khymerian (Province Db) is comparatively recent, initiated by

studies on faunas from Vietnam by Schneider (1971) and Herrig (1975-1978) and on the faunas

of Taiwan by Hu and others (1975-1977) and Malz (1980). The provinciality of the fauna of this

province is strong; 96 of the 142 recorded species appear to be endemic. The fauna demonstrates

strongest connections with that of the adjacent provinces: Da (East Indian) to the south has 10 spcies in common and E (Japan) to the north has 9 species in common (Text-fig. 3a). No common

species occur between this province and provinces B (Arabia), K (Western South American) and

L (Southern Ocean).

The Neogene and Recent faunas of Japan (Province E) are very well documented. Of the 299

species recorded in this province, 244 appear to be endemic. The fauna shows strongest and equal

&ity with that of Da (East Indian) and Db (Khymerian) with 9 species being common in each

case (Text-fig. 3b). Six species are common with the Southern and Southwestern Pacific (Province

H). The majority of species in this province have been recorded by Hanai (1957-1961) and Ishizaki

(1963-1977).



The greatest number of species listed (533) have been recorded in and around Australia (Province F) from the Tertiary and Recent; the majority of Recent species being recorded by Hartmann

(1978-1982). The provinciality of the fauna appears to be poor and the fauna shows strong affinities

with 6 other provinces. The strongest links are with the fauna of the adjacent province H (Southern

and Southwestern Pacific) to the north-east with 61 common species (Text-fig. 3c). Twenty-six species are common to Province Da (East Indian), which is also adjacent to the north-west. The connection with the faunas of the Southern Ocean (0)is illustrated by the 25 species that are common

and connections to the east with 14 species common to New Zealand (G). Province F also has

links with the Indian Ocean region with 13 species common with Eastern Africa (Province A) and

14 with the Bengalian Province (Province C).

The work by Hornibrook (1952) on the ostracods of New Zealand (Province G) was an important contribution to the understanding of Pacific ostracods. The relatively few species in the fauna

(198) exhibit strong provinciality; strongest links are with Australia (F) to the west with 14 common species (Text-fig. 3d). There is also a connection to the north and east with 11 species common

to the Southern and SouthwesternPacific (Province H). There are no common species with Western

North and Central America (Province J).

Province H, Southern and Southwestern Pacific is rather difficult to define on the distribution of

species as provinciality of the fauna is poor. This may be a function of our limited knowledge of the

ostracods of this region. Of the 485 species recorded in the province, only 182 appear to be endemic.

The fauna demonstrates strongest affinity with that of Australia (Province F) to the southwest with

61 common species (Text-fig. 4a). Links are also strong to the northwest with 40 species also



764 S. TITTERTON

AND R. C. WHATLEY



TEXT-FIG.&Link diagrams illustrating the number of endemic species and number of species common with

other provinces for five zoogeographical provinces. 4a, Southern and Southwestern Pacific Province;

4b, Northern and Central Pacific Province; 4, Western North and Central American Province;

4d, Western South American Province; 4e, Southern Ocean Province.



occurring in the East Indies (Province Da). Connections with the Indian Ocean region are illustrated by the 24 species common to Province C (Bengalian) and 19 species common to Province A

(Eastern African). Connections to the north and south are also indicated as 18 species are shared

with Province I (Northern and Central Pacific) and 18 species shared with Province L (Southern

Ocean).

The Northern and Central Pacific (Province I) encompasses several isolated localities, mainly

from around the islands of the Northern and Western Central Pacific Ocean. The faunas from

these scattered localities show little affinity with each other or with other provinces. Affinities of

the 128 species recorded from this region are strongest with the Southern and Southwestern Pacific

(Province H) with 18 common species (Text-fig. 4b). Links with the faunas of the western coasts of

Northern and Central America are indicated by the 7 species common with J. There is also some

connection with Australia (F) with 8 common species.

The Recent faunas of Western North and Central America (Province J) are relatively well documented by a variety of authors. The fauna of 317 species, shows relatively poor affinity with the

Pacific Ocean as only 7 species also occur in I (Northern and Central Pacific) and 9 in H (Southern

and Southwestern Pacific (Text-fig. 4c). There is no connection with the faunas of either Eastern

Africa (A) or New Zealand (G).

The ostracods of Western South America (Province K) are poorly known, most of the species

being recorded by Hartmann (1962, 1965) and Ohmert (1968, 1971). The provinciality of the fauna

of 139 species is strong (Text-fig. 4d). Similarly, the ostracods of Province L (Southern Oceans)

are poorly documented, the majority of the 120 species being recorded prior to 1919 (Text-fig. 4e),

mainly from south of the Indian Ocean.



Provincial Distribution of Shallow Water Indo-Pacifc Marine Ostracoda 765



THEENDEMISM

OF THE FAUNAS

The degree of endemism (or provinciality) of shallow water Indo-Pacific Cainozoic and Recent

ostracods is well illustrated in Text-figs. 2-4. The following tables also illustrate numerically the

levels of endemism in these faunas. One means of doing this is to analyse the extent to which species

are subsequently recorded in provinces other than those in which they were first recorded. Data

based on absolute numbers of species which occur in more than one province is summarized in

Table 1.

TABLE

1-NUMBER

OF SPECIES

WHICH OCCUR

I N MORETHAN 1 PROVINCE.

A

B

C

Da

Db

E

F

G

H

I

J

*

5

2

3

2

1

8

5

8

2

0

2

3

*

1

1

0

0

2

0

2

2

0

c

1

5

*

5

0

0

3

0

4

0

1

ul

D a 3 1 5 1 8

*

2

8 1 3

4 1 8

2

2

Db

0

0

4

8

*

3

3

1

4

1

1

3

E

2

2

2

0

6

*

3

1

3

3

0

3

F

5

8 1 1

13

0

2

*

9 2 2

7

2

E

G

0

2

1

2

0

4

5

*

2

1

0

3

3

H

11

5

20

22

2

3

39

9

* 15

2

E

.I

0

1

1

1

1

0

1

1

3

*

0

0

;0 49

J

0

2

2

3

0

2

2

0

1

7

*

2

K

0

2

0

2

0

1

4

1

2

1

2

08

L

2

1

2

4

0

0

11

1

7

1

2

!%E

21

48

64

54

13

24

94

32

82

42

12

Number of species subsequently recorded in each province.

c



4



!



.g



A

B



K

2

0

0

0

0

0

3 1

0

2

1

5



*



0

12



L

4

0



0

11

0

19

2

87

0

25

2

24

3

95

1 1 8

10

150

1

0

0 3 0

1 1 6

*

31

32



In 7 provinces (A, Da, Db, F, H, J, K) the number of species recorded for the first time in the

province exceed the number of species first recorded elsewhere but subsequently recorded in the

province. In the case of the remaining 6 provinces, (B, C, E, G, I, L), the reverse occurs.

Table 2 shows the number of species common to any two provinces and again can be used to

assess the degree of endemism of any one province.

Numerical and percentage data are combined in Table 3 for all 13 provinces. Columns 1 and 2

give the number and percentage of species restricted to each province and the latter is expressed in

rank order below :

Only the East Indian, Bengalian, Southern and Southwestern Pacific and the Southern Ocean

Provinces have less than 50% endemic species. The level of provincialism in the faunas of the

Western North and Central American, Japanese, Western, South American, New Zealand and the

Khymerian Provinces is very high with over 60% of the species being endemic and that of the

first two provinces being exceptionally high with more than 80 % endemism.

Columns 3 and 4 of Table 3 are important guides to the degree of overall endemism of IndoPacific shallow water ostracod faunas and to certain provinces in particular. Column 3 gives the

number and column 4 the percentage of species which were first recorded only in each of the 13

provinces, but which have subsequently been recorded in other provinces. The percentage of these

species is always less than 20 % and in only 4 provinces is it more than 10%. It can be seen, therefore, that there is a mean of only 8 % of species for all 13 provinces, which once recorded in a province are subsequently recorded elsewhere.

It is the high degree of endemism which enables the recognition of the various provinces considered here. However, it is those species which occur in two or more provinces which make it



766 S. TIITERTON

AND R. C. WHATLEY

TABLE2-THE



NUMBER

OF SPECIES

COMMON

TO TWO PROVINCES.



%

Province J, Western North and Central American

Province E, Japanese

Province K, Western South American

Province G, New Zealand

Province Db, Khyrnerian

Province A, East African

Province F, Australian

Province B, Arabian

Province I, North and Central Pacific

Province Da, East Indian

Province C, Bengalian

Province H, Southern and Southwestern Pacific

Province L, Southern Ocean



81.7

80.2

72.7

69.2

67.6

57.9

56.4

56.2

55.5

39.4

37.4

36.7

35.0



possible to discuss the relationships between the faunas of various provinces, the nature of faunal

migrations between them, and therefore, the possible origins of the faunas.



FAUNAL

hLATIONSHIPS BETWEEN

PROVINCES THROUGHOUT

THE INDO-PACIFIC

Text-figure 5 is a composite species relationship diagram which brings together the number of

species common between all the provinces. Very clearly illustrated in Text-fig. 5 are the following

phenomena :

1. More species occur in the Bengalian, East Indian, Australian and S. W.Pacific regions than

elsewhere and the number of common species between provinces in these regions is markedly

greater than elsewhere. The number of common species between adjacent and near-adjacent

provinces in the complex of the East Indies, Bengal, Australia, Southern and Southwestern

Pacific area are, with only one exception, the only ones to exceed 20. Trans-Pacific faunal links are

very tenuous, even more so than the relatively poor trans-Indian Ocean links. The area of strongest faunal links is also the area where the greatest number of provinces are clustered and also in



TABLE3-THE NUMBER

AND PERCENTAGE OF VARIOUS CATEGORIES OF SPECIES IN EACHPROVINCE



No. of species restricted to province

% of species restricted to province

No. of species originally recorded in

province but subsequently also recorded elsewhere

% of species originally recorded in

province but subsequently also recorded elsewhere

No. of species simultaneously originally

recorded in more than one province

Total number of species originally

recorded from province (1 3 5 )

% of species originally recorded from )

province (1 3 5-10 x 100)

No. of species in province originally

recorded elsewhere (excluding 5 )

% species in province originally

recorded elqewhere (excluding 5 )

Total number of species in province



+ +



+ +



1)

2)



A

128

57.9



B

82

56.2



3)



25



5



4)



11.3



3.4



5



)



6)



154



1



Provinces

C

D a D b

E

F

G

H

59 119

96 240 301 137 178

37.5 39.4 67.6 80.2 56.4 69.2 36.7

15

9.5

1



88



75



7)



69.7



60.3



47.8



8)



66



58



82



9)

10)



.



42



8



13.9



5.6



1



1



162

53.6

140



11

3.6

2



106



43

8.1



2



253



74.6



84.6



36



46



11



75



5



5.5



15.5



3.9



2



6



4



4

348

65.3

185



J

K

259 101

55.5 81.7 72.7



I

71



150

75.7

48



259

53.4

226



9



15



5.0



6.5



12.5



0



1



8



16



80



L

42

35.0



275



111



65



62.5



86.7



79.8



54.1



48



42



28



65



29.9 39.7 52.2 46.3 25.3 20.1 34.7 24.2 46.6 37.5 13.2 20.1 54.1

221 146 157 302 142 299 533 198 485 128 317 139 120



768 S. TITIERTON

AND R. C. WHATLEY



this Bengalian, Indonesian, S. W. Pacific, Australian area, a continuum of shelf environments occurs.

The great distance across the Pacific and the interspersion of an abyssal plain, would only

allow many western American seaboard ostracods to be common with those of the S. W. Pacific

if they could migrate along a shelf continuum via the Aleutians and Japan. The climatic effects of

latitude have clearly prevented this from taking place in the Pacific. Also, but to a much lesser extent, in the Indian Ocean, latitude seems to have influenced the migration of species.

C

157



Db

142



TEXT-FIG.5-Three



link diagrams demonstrating the number of species common between various provinces.



THEMIGRATION

ROUTESOF INDO-PACIFIC

SHALLOW

WATEROSTRACODA

McKenzie (1967) suggested that during the early Tertiary, the Tethys allowed the rapid dispersal

of marine ostracod genera via Simpson’s (1940) methods of migration.

Simpson’s (1940) methods of dispersal, although proposed for land animals, can be applied to

marine animals such as benthonic ostracods. Simpson proposed 3 routes by which animals can

migrate. The corridor route runs parallel to latitude with little climatic change which allows the

active migration of animals, for example across Asia. The filter route requires a narrow channel

which also allows active migration, the example for land animals being the Central American isthmus. Finally, the sweepstakes route involves chance dispersal, possibly by rafts, usually via small

islands.

The Tethys acted as a latitudinal corridor that linked the faunas of the Caribbean, Mediter-



Provincial Distribution of Shallo w Water Indo-Pacific Marine Ostracoda 769



ranean, Indonesian and Australian regions. The Tethys gradually closed during the Neogene, and

since that time the respective faunas have developed more or less independently, the Caribbean and

Gulf Coast regions no longer being directly linked with the Mediterranean and Europe or Indonesia, Australia and the Western Pacific. The links between these regions was illustrated by McKenzie

(1967) by a series of 4 figures showing the Tertiary distribution of the genera Paracypris, Triebelina,

Miocyprideis (herein considered a junior synonym of Neocyprideis) and Caudites. He also gave

other examples of marine myodocopid and podocopid genera that have achieved their present day

distribution via the Tethys. McKenzie suggested that the pelagic fauna could have been carried by

currents and that the benthonic fauna migrated along the continental shelves.The shallow water

benthonic faunas, however, need not necessarily be confined to the shelves. Benson (1979) argues

that the Tethys was an ocean, although without a psychrosphere. It had no links with the colder

waters of the Polar regions, being fed with thermospheric water from the Pacific Ocean. Consequently, decrease in temperature with increasing depth would not be a limiting factor, although

other factors such as increase in pressure may be prohibitive for shallow water faunas.

Although McKenzie (1967) concludes that no single region provided the principal locus for the

adaptive radiation of shallow water ostracod genera during the Tertiary, he implies that the dominant movement of migration was from west to east. For example, he states that the fauna of New

Zealand is endemic because of its position at the end of a sweepstakes route via the island chains

of the Western Pacific Ocean. He illustrates that the genera used as examples, only occur in the

Recent in the Western Pacific and originate from Europe and/or the Gulf Coast. Since 1967, several

more occurrences can be added to the figures given by McKenzie for the distribution of Paracypirs,

Triebelina and Neocyprideis. In particular, Miocene occurrences of Paracypris and Triebelina at

Midway Island (Holden, 1976) and the Quaternary occurrence of Neocyprideis in the Solomon

Islands (Williams, 1980, MS.). The Tertiary to Recent occurrences of Caudites, however, appear

to be correct as far as is known. McKenzie also gives examples of genera that may have migrated

west wards through the Tethys, for example Bythoceratina and Arcacythere, although these are in

the minority. Overemphasis on Mediterranean faunas in discussions on the Tethys may also have

led to the implication that all ostracod taxa originated there. In addition, there is a much greater

knowledge of the ostracods of Europe and the Caribbean, both fossil and Recent, than of Indonesia, the Western Pacific and New Zealand.

Some genera may have reached the Pacific coasts of the Americas from the Gulf Region via the

Panamanian Straits which, prior to the Pliocene, acted as a filter route. Some of these genera are

believed to have crossed the Pacific Ocean from east to west, for example Cushmanidea and Munseyella (McKenzie, 1967). However, the discovery of Munseyella and possible ancestral genera in

the Upper Cretaceous of Western Australia (Bate, 1972) renders this doubtful.

Benson (1979) proposed that the Tethys was a primary channel for world ocean, deep circulation. Water entered the Tethys from the Pacific to the east, moved west and passed south down

the opening South Atlantic and west across the Panamanian Straits to enter the Pacific Ocean again

from the east. Insupport of the view that many genera may have originated from the Pacific is the

fact that this ocean had probably always been in existence during the Phanerozoic. The occurrence

of such “living fossils” as the palaeocopid genera Puncia and Manawa, for example, still found

living off New Zealand and Australia, supports this suggestion, as does the occurrence of Saipanetta in the western Pacific.

Since the Tethys closed during the Neogene, barriers to the migration of species, such as temperature and depth, have led to the establishment of provincial faunas. Some species, however,

have achieved interoceanic dispersal, at least between the Indian and Pacific Oceans. Text-figure

5, showing the links between faunal provinces, suggests that most species are either moving to or

from the Western Pacific. As the Indian Ocean has existed in its present form only since the Tethys



770 S. TITTERTON

AND R. C. WHATLEY



closed, it is suggested that the dominant movement of species across this ocean is eastwards from

the Western Pacific (including Southern Indonesia, Northern Australia and New Zealand). This

does not, however, apply to migration within the Pacific Ocean.



EVIDENCE

OF MIGRATION

ROUTES

FROM INDIVIDUALSPECIES

The 16 species recorded in the Recent of the Solomon Islands that have also been recorded

fossils as there or elsewhere, can be used to trace the direction of movement through geological time.

The earliest fossil record of 4 of these species is in Indonesia or the Phillipines. The oldest record

of Triebelina sertafa Triebel, 1948 (Text-fig. 6) is from the Upper Miocene deposits in the Phillipines (Keij, 1974) and the Lower Pliocene of the Andaman Islands (Guha, 1968) and Northern

Sumatra (Kingma, 1948). This species has migrated westwards to occur in the Recent off Madagascar (Maddocks, 1969a), Reunion Island (Keeler, 1981 MS) the Red Sea (Triebel, 1948), Persian

Gulf (Keij, 1974), Ethiopia (Keij, 1974) and Cyprus (Keij, 1974) and eastwards to the Solomon

Islands, Fiji (Allison and Holden, 1971) and Clipperton Island (Allison and Holden, 1971). The

species has also been recorded in the Recent off British Honduras (Teeter, 1973), Venezuela (Bold,

1948) and the Gulf of Mexico (Puri, 1960).

Tanella gracilis Kingma, 1948 (Text-fig. 7) also possibly occurs in the Recent of the Gulf of

Mexico (Teeter, 1973). Its oldest record is in Pliocene strata of Northern Sumatra (Kingma, 1948)

and it has migrated westwards to occur in the Recent in the Gulf of Manaar (Guha, 1970), around

the coast of India (Jain, 1976, 1978), the Gulf of Oman (Paik, 1977), the Persian Gulf (Bate, 1971;

Teeter, 1973; Paik, 1977), Gulf of Aden (Teeter, 1973) and Suez Canal (Teeter, 1973)and eastwards

to Java (Keij, 1979a), Australia (Hartmann, 1978, 1981) and the Solomon Islands.

Neocyprideis spinulosa (Brady, 1968) (Text-fig. 8) occurs in the Upper Pliocene of Timor (Fyan,

1916) and the Pliocene-Pleistocene of Southern India (Guha, 1968a). This species has spread

westwards to occur in the Recent off Mauritius (Brady, 1868) and Reunion Island (Keeler, 1981,

MS.) and north and eastwards to occur in the Quaternary (Williams, 1980 MS.) and the Recent of

the Solomon Islands, the Philippines (Keij, 1954), New Caledonia (Brady, 1980), Fiji (Brady, 1890)

and the Southeastern Pacific Ocean (Brady, 1880). The fourth species, LeptocythereSoveoreticula~~

(McKenzie, 1982) (Fig. 9) occurs in the Late Pliocene of Java (McKenzie, 1982)and the Recent of

the Solomon Islands.

These 4 species suggest that migration to achieve their present day distribution has been both

westwards and eastwards from the Indonesian Philippine region.

Seven species which have their earliest fossil record in the Solomon Islands also indicate that

the dominant direction of movement is outwards from the Southwestern Pacific and Indonesia.

Neocyprideis timorensis (Fyan, 1916)(Text-fig. 10) occurs in the Miocene (Hughes, 1977MS.) Quaternary (Williams, 1980 MS.) and Recent of the Solomons, the Upper Pliocene of Timor (Fyan,

1916) and the Recent of the Red Sea (Bonaduce et al., 1976 as Bishopina mozarti).

Quadracyfhere sp. (a new species to be described shortly (Text-fig. 11) also occurs in the Miocene, Quaternary and Recent of the Solomons and has been recorded in the Recent off Madagascar (Maddocks, 1966). Hemicytheridea sp. (a new species to be described shortly (Text-fig. 12) was

recorded in Quaternary and Recent deposits in the Solomons and at the present day occurs off the

Philippines (Keij, 1954), Mozambique (Teeter, 1973) and Reunion Island (Keeler, 1981 MS.).

This species also occurs in the Recent off British Honduras and Florida (Teeter, 1973).

Xestoleberis sp. (Text-fig. 13) occurs in the Quaternary and Recent of the Solomons and in the

Recent off Madagascar (Maddocks, 1966). In addition, Cytherella semitalis Brady, 1868 (Text-fig.

14) has been recorded in the Lower Miocene of New Zealand (Swanson, 1969), the Miocene of the



Tài liệu bạn tìm kiếm đã sẵn sàng tải về

Chapter 54. The provincial distribution of shallow-water Indo- Pacific marine Ostracoda: Origins, antiquity, dispersal routes and mechanisms

Tải bản đầy đủ ngay(0 tr)

×