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Cerodinium inflatum
Derivation of name. From the Latin inflatus, inflated, swollen in reference to the inflated nature of the apical horn.
Holotype. Plate 1, figure 1; from a cuttings sample at 2552m, well 25/4-13S; Size, overall length =70um, width =40.5um. Length apical horn =24.5um, width apical horn at base =31um. Endocyst diameter ¼38.5mm. EF coordinates F37.
Type locality. Norwegian North Sea Quad 25 – Alvheim Field, Lista Formation.
Diagnosis. Bicavate to circumcavate peridinioid cyst, dorso-ventrally compressed. Pericyst elongate, smooth, with a long inflated apical horn and two shorter antapical horns. Endocyst sub-circular to ovoidal, thicker and highly folded. Archeopyle intercalary (2a), with a large operculum, free or attached.
Description. Peridinioid cyst, bicavate to circumcavate in shape, and dorso-ventrally compressed. The pericyst is elongate, smooth to minutely scabrate, and exhibits a well-developed, inflated apical horn with a broad base and blunt apex, typically measuring twice or more the length of the antapical horns. The two antapical horns are generally equal in length, though occasionally one may be shorter; both exhibit broad bases and taper to pointed ends. The endocyst is sub- circular to ovoid, markedly darker and thicker than the pericyst, and displays a highly folded surface. The archeopyle is intercalary, formed by the loss of plate 2a that is iso- to lati-deltaform (cf. Text-figure 6 of Bujak and Davies 1983b), with a large operculum that may be free or remain attached.
Dimensions. Overall length of the cyst body 60 (67.5) 73mm, length of apical horn 16.5 (23) 28mm, width of the apical horn at their base 22 (28) 31mm, antapical horns 8 (11) 13mm, diameter of the endocysts 30 (35) 40mm. Number of specimens measured =20.
Comparison. Cerodinium inflatum sp. nov. closely resembles Cerodinium speciosum (Alberti 1959) Lentin and Williams 1987but differs in being generally larger and possessing a more prominently separated, inflated apical horn. It can be distinguished from Cerodinium dartmoorium (Cookson and Eisenack 1965) Lentin and Williams 1987by the absence of granulose ornamentation, and from C. medcalfii (Stover 1974) Lentin and Williams 1987by lacking the more robust ornamentation of spinules and coni. Cerodinium inflatum also differs from C. kangiliense Nøhr-Hansen and Heilmann-Clausen 2001in the absence of intratabular clusters of granulae or echinae.
Holotype. Plate 1, figure 1; from a cuttings sample at 2552m, well 25/4-13S; Size, overall length =70um, width =40.5um. Length apical horn =24.5um, width apical horn at base =31um. Endocyst diameter ¼38.5mm. EF coordinates F37.
Type locality. Norwegian North Sea Quad 25 – Alvheim Field, Lista Formation.
Diagnosis. Bicavate to circumcavate peridinioid cyst, dorso-ventrally compressed. Pericyst elongate, smooth, with a long inflated apical horn and two shorter antapical horns. Endocyst sub-circular to ovoidal, thicker and highly folded. Archeopyle intercalary (2a), with a large operculum, free or attached.
Description. Peridinioid cyst, bicavate to circumcavate in shape, and dorso-ventrally compressed. The pericyst is elongate, smooth to minutely scabrate, and exhibits a well-developed, inflated apical horn with a broad base and blunt apex, typically measuring twice or more the length of the antapical horns. The two antapical horns are generally equal in length, though occasionally one may be shorter; both exhibit broad bases and taper to pointed ends. The endocyst is sub- circular to ovoid, markedly darker and thicker than the pericyst, and displays a highly folded surface. The archeopyle is intercalary, formed by the loss of plate 2a that is iso- to lati-deltaform (cf. Text-figure 6 of Bujak and Davies 1983b), with a large operculum that may be free or remain attached.
Dimensions. Overall length of the cyst body 60 (67.5) 73mm, length of apical horn 16.5 (23) 28mm, width of the apical horn at their base 22 (28) 31mm, antapical horns 8 (11) 13mm, diameter of the endocysts 30 (35) 40mm. Number of specimens measured =20.
Comparison. Cerodinium inflatum sp. nov. closely resembles Cerodinium speciosum (Alberti 1959) Lentin and Williams 1987but differs in being generally larger and possessing a more prominently separated, inflated apical horn. It can be distinguished from Cerodinium dartmoorium (Cookson and Eisenack 1965) Lentin and Williams 1987by the absence of granulose ornamentation, and from C. medcalfii (Stover 1974) Lentin and Williams 1987by lacking the more robust ornamentation of spinules and coni. Cerodinium inflatum also differs from C. kangiliense Nøhr-Hansen and Heilmann-Clausen 2001in the absence of intratabular clusters of granulae or echinae.