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Authority

(H.A.Thomsen) Manton, in Manton & Bremer (1981: 290, figs 1–5)

Class

Craspedophyceae/Choanoflagellida

Order

Choanoflagellida

Family

Acanthoecidae

Additional References

Thomsen et al. (1990: 382, figs 68, 69)

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Basionym

Pleurasiga sphyrelata H.A.Thomsen (1973: 24, figs 22–26)

Synonyms

Campanoeca dilatata Throndsen (1974: 109, figs 2, 8, 29)

Description

Cells solitary. Lorica barrel-shaped, 15–20 µm long, c. 10 µm diameter; longit-udinal costae 7 or 8; transverse costae 3. Longitudinal costae extend for about 10% of their length beyond the anterior transverse costa, each comprising 4 costal strips. Transverse costae comprising 7 or 8 costal strips; costal strips of anterior and middle costae, but only one of the posterior costa, bearing a small square facet in the middle of the costal strip. Protoplast ellipsoidal, 4 µm long, located posteriorly in the lorica; collar of tentacles c. 3 µm long.

Distribution

Inshore areas of Prydz Bay, East Antarctica; New Zealand (Moestrup, 1979); South Africa (Manton et al., 1975); type locality, Denmark (Thomsen, 1973).

Comments

Posteriorly, this organism resembles Polyfibula elatensis (H.A.Thomsen) Manton and P. caudata (B.Leadb.) Manton. However, the arrangement of the remainder of the lorica, especially insofar as the anterior ends of the longitudinal costae neither make T-junctions (as in P. caudata), nor that these costal strips extend well beyond the anterior transverse costal strips as spines (as in P. elatensis), indicates that this organism should be regarded as P. sphyrelata. In the Prydz Bay material, the square costal strip facets were not well developed on the middle and posterior transverse costae.

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