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Echinidinium granulatum
Echinidinium granulatum Zonneveld, 1997, p.325,327-328, pl.2, figs.1-8; text-figs.4A-B ex Head et al., 2001, p.633.
This name was not validly published in Zonneveld (1997) since that author did not provide a Latin diagnosis; such a diagnosis is required since the type is from a sediment trap and thus must be considered modern and not fossil.
Holotype: Zonneveld, 1997, pl.2, figs.1-4.
Age: Holocene.
(Zonneveld, 1997):
1977 Dinoflagellate cyst form D, Wall et al., p. 154, pl. 1, fig. 4.
1996a cf. Protoperidinium sp. 2, Zonneveld, p. 151, pl. l, figs. 5-6.
Holotype: Single grain ARZE 20, Sample MST-9-E3t (Plate II, 1-4).
Repository: Collection of Fachbereich-5 Geowissenschaften, Universitfit Bremen, Germany.
Type locality: Offshore Somalia, Arabian Sea.
Etymology: With reference to the granulate cyst wall.
Diagnosis: Spheroidal cysts covered with numerous randomly distributed spines. Cyst wall pigmented with a thin pedium and a luxuria of isolated granulae. The hollow spines are formed by separation of the luxuria and pedium. The luxuria of the spines is smooth but fine solid spinules can be present at the distal ends of the spines. Spines are acuminate with closed distal ends. The broad spine bases are (sub) sphaerical to ovoidal. The chasmic archeopyle consists of a single split along one or two sutures.
Additional remarks: The spheroidal cysts have a thin pigmented cell wall. In some specimens the granulate luxuria is only faintly visible under light microscopy due to the reduced height of the granules. The amount and height of the spinules at the distal ends of the spines can vary greatly between different specimens and between spines of a single specimen. They are always very small and have not been observed with lengths exceeding the thickness of the spine wall. Specimens from surface samples taken within the Benguela upwelling system exhibit often spinules (R. Hoek, pers. commun., 1996); this feature is mostly lacking in specimens from the Arabian Sea samples. The diameter of the process bases varies between specimens from less than 1/6 to about half of the process length. Spines may be curved and their length is generally 20 to 25% of the body diameter. Some specimens observed in sediment trap samples showed reduced process lengths. In these cases the distal ends of the spines remained closed. The archeopyle is rarely observed but consists of a small split along one or two parasutures. No other paratabulation is reflected.
Dimensions: Holotype: body diameter 33.7 µm; spine length on average 7.4 µm; diameter spine base on average 4.2 µm. Range: body diameter 26-46 µm (mean=33.5 µm, n=18); spine length 5-11 µm (mean=8.5 µm, n=18), diameter spine base 1-5.5 µm (mean=2.5 µm, n = 18).
Comparison with other taxa: Echinidinium granulatum most closely resembles cysts formed by Diplopelta parva (Abe) Matsuoka, 1988 (Matsuoka, 1988) but has a granulate cell wall and can have small spinules at the distal ends of their spines. Furthermore, the chasmic archeopyle of D. parva consist of a split along one long and four short sides whereas the archeopyle of E. granulatum consist of a split along one or two sutures only (Plate II, 5). E. granulatum differs from Diplopelta symmetrica Pavillard, 1913, in having acuminate spines rather than having many hairy-like spines that densely cover the cyst wall. E. granulatum has acuminate spines in contrast to cysts of Protoperidinium minutum (Kofoid) Loeblich, 1969 as described by Wall and Dale (1968) which have short, hollow and more or less flat-topped spines and cysts of P. minutum as described by Fukuyo et al. (1977) which are densely covered with hair-like spines. E. granulatum differs from cysts of Protoperidinium monospinum (Paulsen) Zonneveld et Dale, 1994 in having only one type of spines. It differs from cysts of Pheopolykrikos hartmannii (Zimmermann) Matsuoka et Fukuyo, 1986 in its smaller size, the absence of striations at the proximal bases of the spines and the archeopyle which is formed by a split along one or two sutures. E. granulatum differs from Algidasphaeridium? minutum ( Harland et Reid) Matsuoka et Bujak, 1988 in having hollow spines where small spinules can be present at the distal tips, rather than having spines with hollow bases and solid shafts and distal tips.
Stratigraphic range: Late Pleistocene Recent (Zonneveld, 1996b; Zonneveld et al., 1996a).
Environmental affinity: E. granulatum is most abundant in the Arabian Sea regions characterised by upwelling (Zonneveld, 1996a,b). Furthermore it is observed in the Benguela upwelling (R. Hoek, pets. commun., 1996).
This name was not validly published in Zonneveld (1997) since that author did not provide a Latin diagnosis; such a diagnosis is required since the type is from a sediment trap and thus must be considered modern and not fossil.
Holotype: Zonneveld, 1997, pl.2, figs.1-4.
Age: Holocene.
(Zonneveld, 1997):
1977 Dinoflagellate cyst form D, Wall et al., p. 154, pl. 1, fig. 4.
1996a cf. Protoperidinium sp. 2, Zonneveld, p. 151, pl. l, figs. 5-6.
Holotype: Single grain ARZE 20, Sample MST-9-E3t (Plate II, 1-4).
Repository: Collection of Fachbereich-5 Geowissenschaften, Universitfit Bremen, Germany.
Type locality: Offshore Somalia, Arabian Sea.
Etymology: With reference to the granulate cyst wall.
Diagnosis: Spheroidal cysts covered with numerous randomly distributed spines. Cyst wall pigmented with a thin pedium and a luxuria of isolated granulae. The hollow spines are formed by separation of the luxuria and pedium. The luxuria of the spines is smooth but fine solid spinules can be present at the distal ends of the spines. Spines are acuminate with closed distal ends. The broad spine bases are (sub) sphaerical to ovoidal. The chasmic archeopyle consists of a single split along one or two sutures.
Additional remarks: The spheroidal cysts have a thin pigmented cell wall. In some specimens the granulate luxuria is only faintly visible under light microscopy due to the reduced height of the granules. The amount and height of the spinules at the distal ends of the spines can vary greatly between different specimens and between spines of a single specimen. They are always very small and have not been observed with lengths exceeding the thickness of the spine wall. Specimens from surface samples taken within the Benguela upwelling system exhibit often spinules (R. Hoek, pers. commun., 1996); this feature is mostly lacking in specimens from the Arabian Sea samples. The diameter of the process bases varies between specimens from less than 1/6 to about half of the process length. Spines may be curved and their length is generally 20 to 25% of the body diameter. Some specimens observed in sediment trap samples showed reduced process lengths. In these cases the distal ends of the spines remained closed. The archeopyle is rarely observed but consists of a small split along one or two parasutures. No other paratabulation is reflected.
Dimensions: Holotype: body diameter 33.7 µm; spine length on average 7.4 µm; diameter spine base on average 4.2 µm. Range: body diameter 26-46 µm (mean=33.5 µm, n=18); spine length 5-11 µm (mean=8.5 µm, n=18), diameter spine base 1-5.5 µm (mean=2.5 µm, n = 18).
Comparison with other taxa: Echinidinium granulatum most closely resembles cysts formed by Diplopelta parva (Abe) Matsuoka, 1988 (Matsuoka, 1988) but has a granulate cell wall and can have small spinules at the distal ends of their spines. Furthermore, the chasmic archeopyle of D. parva consist of a split along one long and four short sides whereas the archeopyle of E. granulatum consist of a split along one or two sutures only (Plate II, 5). E. granulatum differs from Diplopelta symmetrica Pavillard, 1913, in having acuminate spines rather than having many hairy-like spines that densely cover the cyst wall. E. granulatum has acuminate spines in contrast to cysts of Protoperidinium minutum (Kofoid) Loeblich, 1969 as described by Wall and Dale (1968) which have short, hollow and more or less flat-topped spines and cysts of P. minutum as described by Fukuyo et al. (1977) which are densely covered with hair-like spines. E. granulatum differs from cysts of Protoperidinium monospinum (Paulsen) Zonneveld et Dale, 1994 in having only one type of spines. It differs from cysts of Pheopolykrikos hartmannii (Zimmermann) Matsuoka et Fukuyo, 1986 in its smaller size, the absence of striations at the proximal bases of the spines and the archeopyle which is formed by a split along one or two sutures. E. granulatum differs from Algidasphaeridium? minutum ( Harland et Reid) Matsuoka et Bujak, 1988 in having hollow spines where small spinules can be present at the distal tips, rather than having spines with hollow bases and solid shafts and distal tips.
Stratigraphic range: Late Pleistocene Recent (Zonneveld, 1996b; Zonneveld et al., 1996a).
Environmental affinity: E. granulatum is most abundant in the Arabian Sea regions characterised by upwelling (Zonneveld, 1996a,b). Furthermore it is observed in the Benguela upwelling (R. Hoek, pets. commun., 1996).