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Homotryblium constrictum
Homotryblium constrictum Islam, 1983
Holotype: Islam, 1983, pl.3, fig.1
Paratype: Islam, 1983
Locus typicus: Sheppey, England
Stratum typicum: Early Eocene
Original diagnosis: Islam, 1983, p. 86
Cyst subspherical to ellipsoidal, proximochorate and biphragmal; endophragm
mildly reticulate or chagrinate; periphragm chagrinate; possesses intratabular short tubular, thinly tubular and solid processes widening at both ends, hollow processes proximally closed and distally open and aculeate, thinly tubular and solid ones distally ramified into palm-like expansions with indented extremities or aculeate or bifurcate; sometimes all process types present in one specimen with tubular ones, if present, preferably posteriorly placed; generally one but sometimes two processes per paraplate define a paratabulation of 4", 6", 6c, 6""", 1p, 1"""", xs; archeopyle epicystal.
Dimensions: Holotype: cyst body 42x39 Ám, length of processes 5-10 Ám. Range: cyst length 34(41)44 Ám, breadth 34(37)42 Ám, length of processes 5-15 Ám.
Affinities:
Islam, 1983, p. 86: This species differs from other species of the genus in possessing very thin and solid processes, and particularly from H. suggestatum Islam 1983 in possessing shorter processes not exceeding 15 Ám in length. This is an unusual species of Homotryblium generally possessing the operculum in place and frequently not showing the archeopyle suture and parasutures of the epicyst as generally seen in other species of the genus. However, dehiscence along the upper paracingular boundary is noticeable in the holotype and split forms occur at Sheppey. It is probably an extreme species of the genus and environmentally sensitive.
Holotype: Islam, 1983, pl.3, fig.1
Paratype: Islam, 1983
Locus typicus: Sheppey, England
Stratum typicum: Early Eocene
Original diagnosis: Islam, 1983, p. 86
Cyst subspherical to ellipsoidal, proximochorate and biphragmal; endophragm
mildly reticulate or chagrinate; periphragm chagrinate; possesses intratabular short tubular, thinly tubular and solid processes widening at both ends, hollow processes proximally closed and distally open and aculeate, thinly tubular and solid ones distally ramified into palm-like expansions with indented extremities or aculeate or bifurcate; sometimes all process types present in one specimen with tubular ones, if present, preferably posteriorly placed; generally one but sometimes two processes per paraplate define a paratabulation of 4", 6", 6c, 6""", 1p, 1"""", xs; archeopyle epicystal.
Dimensions: Holotype: cyst body 42x39 Ám, length of processes 5-10 Ám. Range: cyst length 34(41)44 Ám, breadth 34(37)42 Ám, length of processes 5-15 Ám.
Affinities:
Islam, 1983, p. 86: This species differs from other species of the genus in possessing very thin and solid processes, and particularly from H. suggestatum Islam 1983 in possessing shorter processes not exceeding 15 Ám in length. This is an unusual species of Homotryblium generally possessing the operculum in place and frequently not showing the archeopyle suture and parasutures of the epicyst as generally seen in other species of the genus. However, dehiscence along the upper paracingular boundary is noticeable in the holotype and split forms occur at Sheppey. It is probably an extreme species of the genus and environmentally sensitive.