Alterbia pellucida, (Deflandre and Cookson, 1955), Yun, 1981

Combination illegitimate : the generic name Alterbia is illegitimate.
NOW Isabelidinium pellucidum. Originally Deflandrea bakeri forma pellucida, subsequently Deflandrea pellucida, thirdly Isabelia pellucida (combination illegitimate), fourthly (and now) Isabelidinium pellucidum, fifthly Alterbia pellucida (combination illegitimate); see also Isabelia pellucida (combination illegitimate). Lentin and Williams (1985, p.13) retained this species in Isabelidinium Lentin and Williams, 1977a.

Holotype: Deflandre and Cookson, 1955, pl.4, fig.3
Locus typicus: Nelson bore, Victoria, Australia
Stratum typicum: ?Paleocene-Lower Eocene, Tertiary
Age: Paleocene-Early Eocene.

-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description as Deflandrea bakeri forma pellucida: [Deflandre and Cookson, 1955, p. 251]:

Description:
Membrane of the theca thinner and more finely punctate than that of the type. Outline not especially enlarged in the region of the cyst. Posterior end simply and obliquely truncate, slightly depressed in the middle.

Dimensions:
Type - theca, length 118 µm, breadth 77 µm; cyst, length 67 µm, breadth 74 µm.
Other specimens: length up to 113 µm, breadth up to 92 µm.