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Exochosphaeridium reticulatum
Exochosphaeridium reticulatum Matsuoka, 1984
Holotype: Matsuoka, 1984, pl.72, fig.1
Age: Middle Eocene
Original description Matsuoka, 1984
Derivation of name: Latin, reticulatus, net-like, with reference to the reticulate surface of cyst.
Diagnosis: Cyst subspherical to ovoidal, composed of two layers, periphragm and endophragm appressed between processes. Periphragm clearly reticulate and endophragm smooth. Processes fibrous and tubiform, and basically intratabular but apparently nontabular. Distal part of processes patilate to denticulate and sometimes recurved. Precingular archeopyle with pentagonal margin; operculum detached.
Holotype: Slide NG 43-2 (1gIV), Pl. 72, Fig. 1, sample no. 43, Nangulan Formation; northwest of Yogjakarta, Central Java, Indonesia.
Dimensions: Holotype, length of cyst 66 µm, width 54 µm, length of processes 13-18 µm. Other specimens; length of cyst 66-88µm, width 54µm, length of processes 13-20µm. Number of specimens measured: 10.
Description: The procumochorate cyst has a subspherical to ovoidal shape. The periphragm is relatively thick and reticulate, and the endophragm is thin and smooth. The reticulation of periphragm are clearly observed at the basal part of processes. Processes derived from the periphragm are fibrous, somewhat flexous and slender tubiform, and have similar length within a single specimen. Apical and antapical processes are not differentiated and similar to other processes. The distal parts of processes show patulate to finely denticulate and occasionally recurved. Their distribution of processes appears to be nontabular especially on ventral side, but around the precingular archeopyle and on the free operculum, processes has basically intratabular or penitabular arrangement. These processes are sometimes reduced and become to be fibrous, linear complex forms. The paracingulum is occasionally represented as a linear arrangement of processes especially beneath the precingular archeopyle, but on the ventral side, it is unclear as well as the parasulcus. The archeopyle formed by displacement of the third precingular paraplate is pentagonal in shape. The free operculum provided with about fifteen processes on it.
Remarks: Exochosphaeridium reticulatum is characterized by possession of reticulate periphragm and fibrous processes being basically intratabular or penitabular. This species resembles Exochosphaeridium bifidum (Clarke and Verdier 1967) Clarke et al. 1968 in bearing a fibro-pitted periphragm and fibrous processes, but differs form the latter in having larger number of processes, and lacking in conspicuously branched apical process. The processes of E. reticulatum might be hollow, but it is obscure because of slender and fibrous stalks.
Holotype: Matsuoka, 1984, pl.72, fig.1
Age: Middle Eocene
Original description Matsuoka, 1984
Derivation of name: Latin, reticulatus, net-like, with reference to the reticulate surface of cyst.
Diagnosis: Cyst subspherical to ovoidal, composed of two layers, periphragm and endophragm appressed between processes. Periphragm clearly reticulate and endophragm smooth. Processes fibrous and tubiform, and basically intratabular but apparently nontabular. Distal part of processes patilate to denticulate and sometimes recurved. Precingular archeopyle with pentagonal margin; operculum detached.
Holotype: Slide NG 43-2 (1gIV), Pl. 72, Fig. 1, sample no. 43, Nangulan Formation; northwest of Yogjakarta, Central Java, Indonesia.
Dimensions: Holotype, length of cyst 66 µm, width 54 µm, length of processes 13-18 µm. Other specimens; length of cyst 66-88µm, width 54µm, length of processes 13-20µm. Number of specimens measured: 10.
Description: The procumochorate cyst has a subspherical to ovoidal shape. The periphragm is relatively thick and reticulate, and the endophragm is thin and smooth. The reticulation of periphragm are clearly observed at the basal part of processes. Processes derived from the periphragm are fibrous, somewhat flexous and slender tubiform, and have similar length within a single specimen. Apical and antapical processes are not differentiated and similar to other processes. The distal parts of processes show patulate to finely denticulate and occasionally recurved. Their distribution of processes appears to be nontabular especially on ventral side, but around the precingular archeopyle and on the free operculum, processes has basically intratabular or penitabular arrangement. These processes are sometimes reduced and become to be fibrous, linear complex forms. The paracingulum is occasionally represented as a linear arrangement of processes especially beneath the precingular archeopyle, but on the ventral side, it is unclear as well as the parasulcus. The archeopyle formed by displacement of the third precingular paraplate is pentagonal in shape. The free operculum provided with about fifteen processes on it.
Remarks: Exochosphaeridium reticulatum is characterized by possession of reticulate periphragm and fibrous processes being basically intratabular or penitabular. This species resembles Exochosphaeridium bifidum (Clarke and Verdier 1967) Clarke et al. 1968 in bearing a fibro-pitted periphragm and fibrous processes, but differs form the latter in having larger number of processes, and lacking in conspicuously branched apical process. The processes of E. reticulatum might be hollow, but it is obscure because of slender and fibrous stalks.