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Achilleodinium fibrapendiculum
Williams, Lentin and Fensome 1998 - Lentin and Williams Index of Fossil Dinoflagellates
Achilleodinium fibrapendiculum, Islam, 1983b, p. 335
Holotype: Islam, 1983b pl.1, figs.1-2; text-fig.5.
Locus typicus: Hampshire Basin, S England
Age: Mid Eocene.
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Original description: [Islam, 1983, p. 335]:
Diagnosis:
Cyst ellipsoidal, skolochorate and biphragmal; periphragm fibrous/fibroreticulate; intratabular fibrous processes proximally closed and distally entirely open or closed; epi- and hypocystal processes broad, with more or less equidimensional cross sections, but paracingular processes broad, parallel to paracingulum but very narrow perpendicular to it; anterior processes generally smaller in all dimensions than posterior ones; antapical process sometimes longest and broadest of all, possessing a few lateral spines distally and frequently a closed domal tip; one process per paraplate defining a paratabulation of 4', 6", 4-6c, 5''', 1p, 1'''', xs;
paracingulum slightly helicoidal;
parasulcus sometimes very narrow, straight, extending over both cyst halves;
archeopyle precingular type P, representing paraplate 3", operculum free.
Dimensions:
Holotype: cyst body 52 x 47 µm; length of processes 11-15 µm, breadth 8-15 µm. Range: cyst length 68(54)46 µm, breadth 57(48)44 µm, length and breadth of processes 8-15 µm.
Affinities:
This species differs from others of the genus in possessing fibrous processes. It resembles Cordosphaendium fibrospinosum but differs in possessing narrower paracingular processes and smaller cyst and process dimensions. Cordosphaeridium fibrospinosum is roughly a fourth to twice larger and possesses about twice longer processes, showing no size differentiation between anterior and posterior processes.
Achilleodinium fibrapendiculum, Islam, 1983b, p. 335
Holotype: Islam, 1983b pl.1, figs.1-2; text-fig.5.
Locus typicus: Hampshire Basin, S England
Age: Mid Eocene.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Islam, 1983, p. 335]:
Diagnosis:
Cyst ellipsoidal, skolochorate and biphragmal; periphragm fibrous/fibroreticulate; intratabular fibrous processes proximally closed and distally entirely open or closed; epi- and hypocystal processes broad, with more or less equidimensional cross sections, but paracingular processes broad, parallel to paracingulum but very narrow perpendicular to it; anterior processes generally smaller in all dimensions than posterior ones; antapical process sometimes longest and broadest of all, possessing a few lateral spines distally and frequently a closed domal tip; one process per paraplate defining a paratabulation of 4', 6", 4-6c, 5''', 1p, 1'''', xs;
paracingulum slightly helicoidal;
parasulcus sometimes very narrow, straight, extending over both cyst halves;
archeopyle precingular type P, representing paraplate 3", operculum free.
Dimensions:
Holotype: cyst body 52 x 47 µm; length of processes 11-15 µm, breadth 8-15 µm. Range: cyst length 68(54)46 µm, breadth 57(48)44 µm, length and breadth of processes 8-15 µm.
Affinities:
This species differs from others of the genus in possessing fibrous processes. It resembles Cordosphaendium fibrospinosum but differs in possessing narrower paracingular processes and smaller cyst and process dimensions. Cordosphaeridium fibrospinosum is roughly a fourth to twice larger and possesses about twice longer processes, showing no size differentiation between anterior and posterior processes.