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Bosedinia alveolata
Bosedinia alveolata, Prauss, 2012, p. 289, figs.2A–F,M,3A–H,N–O.
Holotype: Prauss, 2012, fig.2A.
Paratypes: Slide 21, E/F ref. N 33/4, E 44, Fig. 2B, C.
Type locality and stratigraphic horizon: Well-2, Tarfaya Basin, Morocco; upper Turonian–upper Coniacian.
Age: late Turonian–late Coniacian
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Original description: [Prauss, 2012]:
Diagnosis:
A species of Bosedinia with a distinctive alveolate autophragm.
Description:
The alveolae are of different sizes and bipolar in distribution, i.e., larger alveolae are located at the antapical cyst portion and become gradually smaller towards the apical portion. However, there are also specimens with a nearly even distribution of alveolae ( Fig. 2E). Probably as a result of different preservation, the autophragm may be partly dissolved, which results in a mesh-like appearance under the light microscope and perforations under SEM respectively.
Dimensions (in µm):
Holotype: length 48.65, width 57.6.
Paratypes: overall diameter 44.34 (60.48) 82.36.
Other specimens, Well-2, upper Turonian–upper Coniacian, diameter (43 measurements) 36.66 (57.41) 100.89; diameter of alveolae (82 measurements) 0.77 (1.45) 3.6. Specimens from “Mohammed Plage” section, upper Cenomanian–lower Turonian, diameter (36 measurements) 33.1 (39.48) 50.43.
Affinities/Comparison:
Bosedinia alveolata differs from all known species of the genus by the distinctive alveolation of the autophragm. It is otherwise most similar to B. laevigata (Jiabo, 1978 ex He Chengquan and Qian Zeshu, 1979; cf. Fig. 2D, F, G, L, M), which lacks the alveolate wall. In some specimens the alveolation can be rather subtle (Fig. 3A–C, G, H) and may be confused with granulation (cf. Fig. 3N) or with the non-alveolate species B. laevigata (cf. Fig. 2D, F, G). Generally, it is much more prominently developed on specimens from the late Turonian to late Coniacian time interval than on those from the upper Cenomanian–lower Turonian. The coexistence of large numbers of B. alveolata and B. laevigata in several samples is considered indicative of a true species difference rather than a purely ecophenotypic feature.
Holotype: Prauss, 2012, fig.2A.
Paratypes: Slide 21, E/F ref. N 33/4, E 44, Fig. 2B, C.
Type locality and stratigraphic horizon: Well-2, Tarfaya Basin, Morocco; upper Turonian–upper Coniacian.
Age: late Turonian–late Coniacian
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Prauss, 2012]:
Diagnosis:
A species of Bosedinia with a distinctive alveolate autophragm.
Description:
The alveolae are of different sizes and bipolar in distribution, i.e., larger alveolae are located at the antapical cyst portion and become gradually smaller towards the apical portion. However, there are also specimens with a nearly even distribution of alveolae ( Fig. 2E). Probably as a result of different preservation, the autophragm may be partly dissolved, which results in a mesh-like appearance under the light microscope and perforations under SEM respectively.
Dimensions (in µm):
Holotype: length 48.65, width 57.6.
Paratypes: overall diameter 44.34 (60.48) 82.36.
Other specimens, Well-2, upper Turonian–upper Coniacian, diameter (43 measurements) 36.66 (57.41) 100.89; diameter of alveolae (82 measurements) 0.77 (1.45) 3.6. Specimens from “Mohammed Plage” section, upper Cenomanian–lower Turonian, diameter (36 measurements) 33.1 (39.48) 50.43.
Affinities/Comparison:
Bosedinia alveolata differs from all known species of the genus by the distinctive alveolation of the autophragm. It is otherwise most similar to B. laevigata (Jiabo, 1978 ex He Chengquan and Qian Zeshu, 1979; cf. Fig. 2D, F, G, L, M), which lacks the alveolate wall. In some specimens the alveolation can be rather subtle (Fig. 3A–C, G, H) and may be confused with granulation (cf. Fig. 3N) or with the non-alveolate species B. laevigata (cf. Fig. 2D, F, G). Generally, it is much more prominently developed on specimens from the late Turonian to late Coniacian time interval than on those from the upper Cenomanian–lower Turonian. The coexistence of large numbers of B. alveolata and B. laevigata in several samples is considered indicative of a true species difference rather than a purely ecophenotypic feature.