Type species: Heterohelix navarroensis Loeblich, 1951, p. 107, pl. 12, figs 1-3.

Diagnosis.– Test with early planispiral coil and weak test wall flexure on the periphery of the earlier portion of the test.

Description.– Test with early planispiral coil and biserial in the adult stage. Earlier chambers are globular, those of the adult stage subglobular. Periphery slightly subangular with a weak test wall flexure developed mostly on the cham- bers of the earlier portion of the test. Aperture is a low to medium high arch at the base of the last formed chamber. Two small, symmetrical flanges border the aperture on the lateral sides. Chamber surface is costate and with orna- mentation thickenings in the proximity of the ‘zigzag’ suture on the earlier chambers. Test wall calcitic, hyaline, finely perforate to macroperforate.

Remarks.– Paraspiroplecta nov. gen. differs from Hendersonia nov. gen. by the presence of the early planispiral coil. Spiroplecta Ehrenberg, 1844 presents more globular chambers, which can be best seen in the edge view, and has smaller pores (0.7 to 1.3 µm rather than 1.5-3.2 µm). These suggest that Spiroplecta is apparently a descendant from a species of the Heterohelix globulosa (Ehrenberg,1840) group.
Species included.– Heterohelix navarroensis Loeblich, p.107, Pl. 12, Figs. 1-3.

Phylogenetic relationships.– Paraspiroplecta  nov. gen. evolved from Hendersonia nov. gen. It became extinct in the proximity of the Cretaceous/Tertiary boundary leaving no descendants (Fig. 4).

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