4.16
Biogeographical Change in the Latitudinal Boundary of a
Bisubtropical Pteropod Styliola subula (QUOY et GAIMARD)
in the Indian Ocean
M.SAKTHIVEL
The geographical distribution and relative abundance of the bisubtropical pteropod
Styliola suhula is given in Fig. 1. This species has a wide range of distribution from
10° N to 40° S and is very rare or absent in the Indian Ocean north of 10° N and south
D 1-19
D 20-39
_ 40 - 79
Fig. 1. Distribution of Styliola subula in the Indian Ocean
of 40° S. The sparse occurence of this species between 5° Nand 10° N, and 30° Sand
40° S is noticed in the present study. There were 579 collections from north of 10° N:
except for a single record of a single specimen from AB 175 at 17° 26'N and 56° 57'E,
none of them contained this species. Therefore, the extreme scarcity of S. subula in the
Biogeographical Change in the Latitudinal Boundary of a
Bisubtropical Pteropod Styliola subula (QUOY et GAIMARD)
in the Indian Ocean
M.SAKTHIVEL
The geographical distribution and relative abundance of the bisubtropical pteropod
Styliola suhula is given in Fig. 1. This species has a wide range of distribution from
10° N to 40° S and is very rare or absent in the Indian Ocean north of 10° N and south
D 1-19
D 20-39
_ 40 - 79
Fig. 1. Distribution of Styliola subula in the Indian Ocean
of 40° S. The sparse occurence of this species between 5° Nand 10° N, and 30° Sand
40° S is noticed in the present study. There were 579 collections from north of 10° N:
except for a single record of a single specimen from AB 175 at 17° 26'N and 56° 57'E,
none of them contained this species. Therefore, the extreme scarcity of S. subula in the