R. Kruger et al., BIOLOGY AND REPRODUCTIVE PROCESSES OF THE LARGER FORAMINIFERAN CYCLOCLYPEUS-CARPENTERI (PROTOZOA, NUMMULITIDAE), Archiv fur Protistenkunde, 147(3-4), 1997, pp. 307-321
Gamonts and agamonts of the extant nummulitid Cycloclypeus carpenteri
were collected from a depth between 45 and 61 m, near Okinawa (Ryukyu
Islands, Japan) and maintained in the laboratory in Kiel (Germany) unt
il they reproduced. All of them grew in the laboratory, including dama
ged specimens, which regenerated more or less regular tests. Like othe
r nummulitids, they formed sheaths for attachment, complete in young a
nd incomplete in adult specimens. Eighteen agamonts formed gamonts in
the laboratory, the first reproducing after 5.5 months and the last af
ter 9.2 months of maintenance. The process of multiple fission can be
divided into 5 well defined periods. During the formation of the two-c
hambered embryonic apparatuses, the symbiotic diatoms are apportioned
to the daughter cells by a highly organized process that is identical
in all nummulitids. The number of gamonts provided by 3 agamonts was 1
740, 1910 and 2540. The mean prolocular size in the two-chamber stage
of the gamonts was 263 mu m (minimum 200 mu m, maximum 327 mu m). The
mean size of 5 gamonts from the natural habitat was 8.1 mm on the day
of reproduction. The mean size of 39 gamonts from laboratory culture w
as 8.6 mm. Gamete formation began at an age of about 11 months and end
ed at an age of about 13 months. Gamonts released their 2.5-3.0 mu m b
iflagellated gametes over 0.7 to 15 hours mainly during the light peri
od.