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Anthocyrtella (?) callopisma
Caulet, 1986
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Description - Add description
Anthocyrtella spA
The first three segments are porous and the pores are very large, often irregular in the fourth segment. Some longitudinal ribs may be seen in the walls of the fourth segment. The first segment is the narrowest, the fourth is the broadest. All the segments are separated from one another by the inner ring and the external constriction. Not very abundant but rather typical in the Antarctic Miocene. Some specimens with undeveloped fourth segment (which has very small pores) also occur (Plate 15, Figures 4, 5).
| | Petrushevskaya 1975 | Anthocyrtella (?) callospima
Description: Cephalis subglobose, with small pores. Fundamental spicule reduced to bars separating four collar pores. Apical spine thin, vertical. Vertical spine, oblique, very short. No axobate. Collar stricture slightly marked by a progressive change in external contour. Shell conical, consisting of four segments, separated by inner rings. Thorax truncate-conical, spiny, with thin walls perforated by circular pores of irregular size. About 8-10 pores on a half-circumference. Abdomen truncate-conical with longitudinal ribs and spines. A total of 8-10 subcircular pores on a half-circumference. Pores increase in size distally. Fourth segment with indistinct termination, truncate-conical. Large pores of irregular shape and increasing distally. One or two ribs prolonged outward as thin acicular feet of the same length as the fourth segment.
Dimensions: (Based on 20 specimens). Total length (excluding apical horn and terminal feet) 100-120 µm; maximum width 75 µm, length of cephalis (excluding apical horn) 10-16 µm; length of thorax 18-20 µm; length of third segment 22-25 µm; maximum length of terminal feet 42µm.
Name: ornamented (Greek).
Holotype: (Plate I, 1,2), sample AET 75002, 10 cm, slide 1.
Remarks: Assignment of these specimens to the genus Anthocyrtella is not satisfactory because Eocene forms described by Ehrenberg (1872) are very different. However, the choice of Petrushevskaya has been retained here to avoid a confusing situation. Additional study is necessary before considering a good generic placement for this morphotype. Because its stratigraphic range appears to be relatively short and useful for biostratigraphy, it is convenient to give it a species name. | | Caulet 1986 |
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