Diagnosis.– Haigella with triserial test and chambers of the adult stage with lateral projections.

Description.– Test with curved growth axis and triserial chamber arrangement. Earlier chambers are globular, those of the adult stage present short, backward oriented lateral projections (Pl. 5, Figs 7-14). A line of tubercles lines up the chamber projections in the adult stage (Pl. 5, Figs 7, 8, Pl. 7, Fig. 2). Earlier part of the test with rounded periphery; the chambers of the adult portion of the test present subacute to acute periphery due to the development of backward oriented chamber projections. Sutures are distinct, deeply incised, straight or slightly curved.

Aperture is single, elliptical in shape and subterminal in position (Pl. 5, Figs 10, 14). It is bordered by an asymmetrically developed imperforate rim. A supplementary suture is present on the apertural face, between the base of the aperture and the suture between the last-formed and penultimate chamber (Pl. 5, Figs 10, 14). Chamber surface is smooth. Test wall is calcitic, hyaline and nannoperforate, with pore diameter ranging between 0.2 and 0.5 µm (Pl. 7, Fig. 2).

Remarks.– Haigella haigi differs from H. intermedia by being completely triserial and bearing well developed backward-oriented chamber projections in the adult stage.

The specimens with relatively similar gross test architecture reported from the lower Turonian (offshore Ghana, equatorial Atlantic Ocean) and assigned to Praebulimina sp. 1 by Holbourn & Kuhnt (1998, p. 363, pl. 3, figs 1-2) cannot be included within Haigella. They present chamber projections without lined peripheral tubercles and aperture situated at the base of the apertural face, without relict suture.

References: