Back
Exochosphaeridium brevispinosum
Exochosphaeridium brevispinosum Matsuoka, 1984
Holotype: Matsuoka, 1984, pl.72, fig.7
Age: Middle Eocene
Original description Matsuoka, 1984: Exochosphaeridium brevispinosum sp. nov. (Pl. 72, Figs. 6-9)
Derivation of name: Latin, brevis + spinosum; short spine, with refence tot he short processes.
Diagnosis: Cyst spherical to ovoidal and intermediate in size. Cyst wall composed of two layers, periphragm and endophragm appressed between processes. Processes strongly fibrous, and short and widely cylindrical. Their distribution fundamentally intratabular, but apparently nontabular. The wall of the processes becoming loose. Distal extremities of processes denticulate. Archeopyle precingular; operculum free.
Holotype: Slide NG 33-2 (6gI), Pl. 72, Fig. 7, sample no. NG 33, Nanggulan Formation; Middle Eocene. Location; Kalisongo, 20 km northwest of Yogajakarta, Central Java, Indonesia.
Dimensions: Holotype: length of cyst 69 µm, width 63 µm, length of processes 9 µm. Other specimens; length of cyst 53-69 µm, width 53-63 µm; length of processes 7-9 µm.
Number of specimens measured: 5.
Description: the proximochorate cyst is intermediate in size and spherical to ovoidal in shape. The periphragm is moderately thick and strongly fibrous. The fibro-pitted structure is developed around the proximal base of the processes. The endophragm is thin, smooth. The processes composed of several strings are short and widely cylindrical and seem to be hollow. Their walls show a reticulate structure and their distal extremities are apparently denticulate. The intratabular distribution of processes is clearly indicated around the archeopyle. About fifteen processes are developed in one paraplate are based on the detached operculum. The processes are similar in length and structure within a single specimen. The cingulum is occasionally represented by a linear distribution of the process beneath the basal parasuture of the process beneath the basal parasuture of the precingular archeopyle. Except for the archeopyle might be derived from the loss of 3’’ paraplate based on shape of the free operculum.
Remarks: This species is similar to Exochosphaeridium reticulatum n. sp. in having a fibro-pitted periphragm and fibrous processes, but distinguishable from the latter in possessing shorter and wider, and strongly fibrous cylindrical processes. Nevertheless, the intermediate forms were encountered in the material of the Nangulan Formation.
Holotype: Matsuoka, 1984, pl.72, fig.7
Age: Middle Eocene
Original description Matsuoka, 1984: Exochosphaeridium brevispinosum sp. nov. (Pl. 72, Figs. 6-9)
Derivation of name: Latin, brevis + spinosum; short spine, with refence tot he short processes.
Diagnosis: Cyst spherical to ovoidal and intermediate in size. Cyst wall composed of two layers, periphragm and endophragm appressed between processes. Processes strongly fibrous, and short and widely cylindrical. Their distribution fundamentally intratabular, but apparently nontabular. The wall of the processes becoming loose. Distal extremities of processes denticulate. Archeopyle precingular; operculum free.
Holotype: Slide NG 33-2 (6gI), Pl. 72, Fig. 7, sample no. NG 33, Nanggulan Formation; Middle Eocene. Location; Kalisongo, 20 km northwest of Yogajakarta, Central Java, Indonesia.
Dimensions: Holotype: length of cyst 69 µm, width 63 µm, length of processes 9 µm. Other specimens; length of cyst 53-69 µm, width 53-63 µm; length of processes 7-9 µm.
Number of specimens measured: 5.
Description: the proximochorate cyst is intermediate in size and spherical to ovoidal in shape. The periphragm is moderately thick and strongly fibrous. The fibro-pitted structure is developed around the proximal base of the processes. The endophragm is thin, smooth. The processes composed of several strings are short and widely cylindrical and seem to be hollow. Their walls show a reticulate structure and their distal extremities are apparently denticulate. The intratabular distribution of processes is clearly indicated around the archeopyle. About fifteen processes are developed in one paraplate are based on the detached operculum. The processes are similar in length and structure within a single specimen. The cingulum is occasionally represented by a linear distribution of the process beneath the basal parasuture of the process beneath the basal parasuture of the precingular archeopyle. Except for the archeopyle might be derived from the loss of 3’’ paraplate based on shape of the free operculum.
Remarks: This species is similar to Exochosphaeridium reticulatum n. sp. in having a fibro-pitted periphragm and fibrous processes, but distinguishable from the latter in possessing shorter and wider, and strongly fibrous cylindrical processes. Nevertheless, the intermediate forms were encountered in the material of the Nangulan Formation.