Back
Bosea
From Williams et al., 2017:
[Bosea, He Cheng-quan and Qian Ze-shu, 1979, p. 177-179
Type species: Bosea granulata, He Chengquan and Qian Zeshu, 1979 (pl.1, fig.2)]
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [He Chen-quan and Qian Ze-shu, 1979]: (Translations: Chen et al., 1988, p. 14-15, GSC, courtesy R. Fensome):
Description:
Cysts proximate, spherical to subovoidal. Apical and antapical horns absent. Paracingulum, parasulcus and paratabulation not shown. Archeopyle indicated by a `circular opening`, perhaps of the epicystal type, generally located at the widest part of the body. Operculum adnate or free. Hypocyst larger than epicyst. Surface smooth, scabrate, or rugulate; no spine-like processes.
GSC:
Affinities/Comparison and Discussion:
This new genus bears a resemblance to Chytroeisphaeridia Sarjeant. The difference between the two lies in the fact that the "pylome" in this new genus is rather large and is frequently positioned at the point where the tract reaches its maximum width, as well as the fact that it rises to a height equal to approximately one-third of the tract`s diameter. This "pylome" is significantly different from the apical archaeopyle of the latter genus. Moreover, the operculum in this genus is often attached, whereas in Chytroeisphaeridia the operculum usually is lost. The shape of the archaeopyle in this new genus is quite similar to that seen in Energlynia Sarjeant, 1976. The latter genus, however, may have indistinct tabulation (the signs of tabulation are difficult to make out from the photographs - the authors), or tabulation may be completely absent. In cases where faunal elements belonging to Energlynia lack reflected tabulation (see Sarjeant, 1976a, Geobios, No. 9, Pl. 1, Fig. 3, p. 16), the only distinction between this new genus and the latter lies in the presence or absence of antapical horns. Energlynia is a dinoflagellate cyst that has an epitractal archaeopyle. The genera listed below share many morphological features in common with this new genus. Nevertheless, they can be distinguished from this new genus by the characteristics cited: Batiacasphaera Drugg, 1970, by the fact that it possesses a horn-like apical archaeopyle; Palaeostomocystis Deflandre, by the fact that its tract has an elongated oval shape and a pylome that is apically situated; and Tenua (Eis., 1958) Sarjeant, by the fact that it bears spine-like processes. Consequently, some species that should be transferred to this new genus include Bosea (al. Rugosphaera) operculata (Jiabo, 1978) comb. nov., Bosea (al. Palaeostomocystis) laevigata (Jiabo, 1978) comb. nov., and Bosea (al. Palaeostomocystis) scabrata (Jiabo, 1978) comb. nov. Two lines of evidence suggest that these organisms may be dinoflagellate cysts. First, the "pylome" or rounded opening is large in the vast majority of specimens, and it seems that this is a manifestation of the fact that the position and characteristics of this opening are different from the rounded openings that are ordinarily seen on the epitheca of acritarchs. Nevertheless, the opening generally does not appear to be polygonal, and as a result the authors have put quotation marks around the term "pylome" that is being used for these rounded openings to signify the difference. It is also possible that this [opening] is an epitractal archaeopyle (in some specimens, the characteristics of an attached archaeopyle or an apical archaeopyle seem to be suggested). Secondly, the openings that are observed in nearly all of the specimens are laterally positioned, which seems to indicate that the organism was not spherical and exhibited characteristics similar to those of dorsoventrally flattened dinoflagellates. All of these materials await further research sometime in the future.
This genus occurs here in China in Lower Tertiary strata in the coastal area of the Bohai Sea and in the Bose Basin of Guangxi. Similar elements have been found in Upper Tertiary beds in Romania.
[Bosea, He Cheng-quan and Qian Ze-shu, 1979, p. 177-179
Type species: Bosea granulata, He Chengquan and Qian Zeshu, 1979 (pl.1, fig.2)]
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [He Chen-quan and Qian Ze-shu, 1979]: (Translations: Chen et al., 1988, p. 14-15, GSC, courtesy R. Fensome):
Description:
Cysts proximate, spherical to subovoidal. Apical and antapical horns absent. Paracingulum, parasulcus and paratabulation not shown. Archeopyle indicated by a `circular opening`, perhaps of the epicystal type, generally located at the widest part of the body. Operculum adnate or free. Hypocyst larger than epicyst. Surface smooth, scabrate, or rugulate; no spine-like processes.
GSC:
Affinities/Comparison and Discussion:
This new genus bears a resemblance to Chytroeisphaeridia Sarjeant. The difference between the two lies in the fact that the "pylome" in this new genus is rather large and is frequently positioned at the point where the tract reaches its maximum width, as well as the fact that it rises to a height equal to approximately one-third of the tract`s diameter. This "pylome" is significantly different from the apical archaeopyle of the latter genus. Moreover, the operculum in this genus is often attached, whereas in Chytroeisphaeridia the operculum usually is lost. The shape of the archaeopyle in this new genus is quite similar to that seen in Energlynia Sarjeant, 1976. The latter genus, however, may have indistinct tabulation (the signs of tabulation are difficult to make out from the photographs - the authors), or tabulation may be completely absent. In cases where faunal elements belonging to Energlynia lack reflected tabulation (see Sarjeant, 1976a, Geobios, No. 9, Pl. 1, Fig. 3, p. 16), the only distinction between this new genus and the latter lies in the presence or absence of antapical horns. Energlynia is a dinoflagellate cyst that has an epitractal archaeopyle. The genera listed below share many morphological features in common with this new genus. Nevertheless, they can be distinguished from this new genus by the characteristics cited: Batiacasphaera Drugg, 1970, by the fact that it possesses a horn-like apical archaeopyle; Palaeostomocystis Deflandre, by the fact that its tract has an elongated oval shape and a pylome that is apically situated; and Tenua (Eis., 1958) Sarjeant, by the fact that it bears spine-like processes. Consequently, some species that should be transferred to this new genus include Bosea (al. Rugosphaera) operculata (Jiabo, 1978) comb. nov., Bosea (al. Palaeostomocystis) laevigata (Jiabo, 1978) comb. nov., and Bosea (al. Palaeostomocystis) scabrata (Jiabo, 1978) comb. nov. Two lines of evidence suggest that these organisms may be dinoflagellate cysts. First, the "pylome" or rounded opening is large in the vast majority of specimens, and it seems that this is a manifestation of the fact that the position and characteristics of this opening are different from the rounded openings that are ordinarily seen on the epitheca of acritarchs. Nevertheless, the opening generally does not appear to be polygonal, and as a result the authors have put quotation marks around the term "pylome" that is being used for these rounded openings to signify the difference. It is also possible that this [opening] is an epitractal archaeopyle (in some specimens, the characteristics of an attached archaeopyle or an apical archaeopyle seem to be suggested). Secondly, the openings that are observed in nearly all of the specimens are laterally positioned, which seems to indicate that the organism was not spherical and exhibited characteristics similar to those of dorsoventrally flattened dinoflagellates. All of these materials await further research sometime in the future.
This genus occurs here in China in Lower Tertiary strata in the coastal area of the Bohai Sea and in the Bose Basin of Guangxi. Similar elements have been found in Upper Tertiary beds in Romania.