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Pierceites
From Williams et al., 2017:
[Pierceites, Habib and Drugg, 1987, p. 761
Type species: Pierceites schizocystis, Habib and Drugg, 1987 (pl.6, fig.1)]
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Original description: [Habib and Drugg, 1987]:
Diagnosis:
Proximate peridinioid dinoflagellate cysts, with one smoothly tapering apical horn and two unequally developed antapical horns. Wall layers closely appressed, without pericoels. Archeopyle 3I. Operculum compound, with three opercular pieces corresponding to plates of intercalary series; opercular pieces free; when they remain in place, each is always completely outlined by an archeopyle suture. Cyst tabulation, if present, is peridiniacean; it is expressed by sutural lines of dehiscence defining plate boundaries, and not by positive structures such as ridges, septa, or processes, or by patterns of ornamentation.
Affinities:
Pierceites is distinguished from other peridinioid genera with the 3I archeopyle by its lack of pericoels underlying any area of the periphragm. Except for the archeopyle, it may lack any evidence of tabulation. However, when it is expressed, it is by sutural lines of dehiscence which define plate boundaries in the cyst. Both Trithyrodinium Drugg and Ginginodinium Cookson and Eisenack possess a 3I archeopyle, but are proximocavate. Also, in the latter genus, when there is evidence of tabulation it is expressed by positive features of the periphragm. Pareodinia wiggins may also possess a 3I archeopyle, but does not possess antapical horns.
[Pierceites, Habib and Drugg, 1987, p. 761
Type species: Pierceites schizocystis, Habib and Drugg, 1987 (pl.6, fig.1)]
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Original description: [Habib and Drugg, 1987]:
Diagnosis:
Proximate peridinioid dinoflagellate cysts, with one smoothly tapering apical horn and two unequally developed antapical horns. Wall layers closely appressed, without pericoels. Archeopyle 3I. Operculum compound, with three opercular pieces corresponding to plates of intercalary series; opercular pieces free; when they remain in place, each is always completely outlined by an archeopyle suture. Cyst tabulation, if present, is peridiniacean; it is expressed by sutural lines of dehiscence defining plate boundaries, and not by positive structures such as ridges, septa, or processes, or by patterns of ornamentation.
Affinities:
Pierceites is distinguished from other peridinioid genera with the 3I archeopyle by its lack of pericoels underlying any area of the periphragm. Except for the archeopyle, it may lack any evidence of tabulation. However, when it is expressed, it is by sutural lines of dehiscence which define plate boundaries in the cyst. Both Trithyrodinium Drugg and Ginginodinium Cookson and Eisenack possess a 3I archeopyle, but are proximocavate. Also, in the latter genus, when there is evidence of tabulation it is expressed by positive features of the periphragm. Pareodinia wiggins may also possess a 3I archeopyle, but does not possess antapical horns.