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Deflandrea acutula
Deflandrea acutula Wilson, 1967
Now Alterbidinium. Originally Deflandrea, subsequently (and now) Alterbidinium. See also Alterbia (combination illegitimate).
Tax. sr. synonym of Alterbia recticornis (Vozzhennikova, 1967) Lentin and Williams, 1976, according to Whitney, 1979.
Harker and Sarjeant in Harker et al., 1990, retained Alterbia (as Alterbidinium) recticornis as a separate species.
Lentin and Vozzhennikova, 1990, Khowaja-Ateequzzaman et al., 1991, and Lentin and Williams, 1993, regarded Alterbidinium recticorne as a tax. jr. synonym of Alterbidinium acutulum (Wilson, 1967) Lentin and Williams, 1985.
Tax. sr. synonym of Alterbia curvicornis (Vozzhennikova, 1967) Lentin and Williams, 1976, according to Whitney, 1979.
Khowaja-Ateequzzaman et al., 1991, emended the diagnosis of this species, as Alterbidinium acutulum.
Holotype: Wilson, 1967, fig.12
Locus typicus: Garden Cove Mudston at Head of Persevance Habour, Campbell Island, New Zealand
Stratum typicum: ?Teurian, Palaeocene
Original descriptoin: Wilson, 1967, p.225-226
Test narrow, bi-layered, comprising smooth outer cyst tapering at poles, and smaller inner cyst. Right antapical horn long (l=14-36 µm), pointed. Left antapical horn absent, but position represented by minor angularity in margin of outer cyst. Archaeopyle long, narrow, intercalary, situated on dorsal epitheca; operculum hinged to shell by posterior margin. Spiral transverse girdle represented by a folding of outer cyst.
Dimensions: Holotype: l=83 µm, b=44 µm, inner cyst 44x36 µm. Two other measured specimens: SM 621: l=116 µm, b=47 µm, inner cyst 47x39 µm; SM 602: l=94 µm, b=50 µm, inner cyst=44x41 µm.
Affinities:
Wilson, 1967, p.226: D. acutula shares certain features with sveral Antarctic species of Deflandrea described recently by the author (Wilson, 1967). In particular the archaeopyle resembles that of D. assymetrica and D. distincta, although it is much narrower. All three species possess a flat-tipped apical horn. D. acutula is distinguished from the two Antarctic species by its different shell outline, greater development of the right antapical horn, and the absence of a left antapical horn.
Now Alterbidinium. Originally Deflandrea, subsequently (and now) Alterbidinium. See also Alterbia (combination illegitimate).
Tax. sr. synonym of Alterbia recticornis (Vozzhennikova, 1967) Lentin and Williams, 1976, according to Whitney, 1979.
Harker and Sarjeant in Harker et al., 1990, retained Alterbia (as Alterbidinium) recticornis as a separate species.
Lentin and Vozzhennikova, 1990, Khowaja-Ateequzzaman et al., 1991, and Lentin and Williams, 1993, regarded Alterbidinium recticorne as a tax. jr. synonym of Alterbidinium acutulum (Wilson, 1967) Lentin and Williams, 1985.
Tax. sr. synonym of Alterbia curvicornis (Vozzhennikova, 1967) Lentin and Williams, 1976, according to Whitney, 1979.
Khowaja-Ateequzzaman et al., 1991, emended the diagnosis of this species, as Alterbidinium acutulum.
Holotype: Wilson, 1967, fig.12
Locus typicus: Garden Cove Mudston at Head of Persevance Habour, Campbell Island, New Zealand
Stratum typicum: ?Teurian, Palaeocene
Original descriptoin: Wilson, 1967, p.225-226
Test narrow, bi-layered, comprising smooth outer cyst tapering at poles, and smaller inner cyst. Right antapical horn long (l=14-36 µm), pointed. Left antapical horn absent, but position represented by minor angularity in margin of outer cyst. Archaeopyle long, narrow, intercalary, situated on dorsal epitheca; operculum hinged to shell by posterior margin. Spiral transverse girdle represented by a folding of outer cyst.
Dimensions: Holotype: l=83 µm, b=44 µm, inner cyst 44x36 µm. Two other measured specimens: SM 621: l=116 µm, b=47 µm, inner cyst 47x39 µm; SM 602: l=94 µm, b=50 µm, inner cyst=44x41 µm.
Affinities:
Wilson, 1967, p.226: D. acutula shares certain features with sveral Antarctic species of Deflandrea described recently by the author (Wilson, 1967). In particular the archaeopyle resembles that of D. assymetrica and D. distincta, although it is much narrower. All three species possess a flat-tipped apical horn. D. acutula is distinguished from the two Antarctic species by its different shell outline, greater development of the right antapical horn, and the absence of a left antapical horn.