Modern Dinocyst Key

Cyst of Archaeperidinium bailongense Mertens et al., 2015

Characteristics:
Cysts are subspherical, light brown and covered with numerous apiculocavate processes. Wall is granulate. Processes have a narroww circular base with capitate distal ends. Processes are generally of equal length but some smaller processes can be present. Archeopyle is theropylic corresponding to plate 2a.


Dimensions: Cyst body: 38.3 to 50.3 µm diameter, Process length: mean: 6.4 to 10.3 µm, Process density: 4 to 7 processes 10 x 10 µm2.
Motile affinity: Archaeperidinium bailongense.
Stratigraphic range: Recent.

Comparison with other species:
Cysts most closely resemble cysts of Protoperidinium tricingulatum in having a apiculocavate captivated processes. The major difference is the granulate wall and the theropylic archeopyle along plater 2a with cysts of Protoperidinium tricingulatum having a smooth to micro granulate wall surface and an archeopyle along the plate boundaries of 2‘/1a, 2‘/2a, 3‘/2a, 4‘/2a, 4‘/6“, 4’/7“. Cysts of A. bailongense can have processes with different length. However, when the archeopyle is not visible, both species can not be separated by light-microscope.