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Broomea fusticula
From Fensome et al., 2019:
Broomea fusticula Mantle, 2009a, p.44–46, pl.6, figs.1–8; text-fig.9. Holotype: Mantle, 2009a, pl.6, fig.1. Age: Callovian.
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Original description: [Mantle, 2009a]:
Broomea fusticula sp. nov.
Plate 6, Figs 1-8; Text-fig. 9
Diagnosis: Cysts proximate, acavate, elongate-ovoidal, surmounted by a long, slender, apical horn. Antapex densely sculptured with grana and sparse verrucae; irregularly shaped, spongeous phragma commonly extending as 2 short antapical horns or as a thickened, sometimes bilobate, antapical boss. Cyst wall double-layered; endo- and periphragm closely appressed. Periphragm scabrate to granulate with sculpture
coarsening polewards. Paratabulation lacking, other than that suggested by archeopyle outline and paracingular folds. Intercalary archeopyle rarely evident, involving loss of 1 intercalary paraplate.
Description: An elongate, club-like proximate cyst with a long apical horn (up to 65 pm long) and narrow antapex. The scabrate to granulate periphragm is commonly folded, thickened antapically, and may develop low ridges along the paracingulum margins. The broad-based, apical horn tapers uniformly to a rounded tip, which is typically surmounted by a narrow apicular structure. The antapex and distal one-third of the apical horn bear coarser grana than the rest of the cyst. The antapex, formed of thickened periphragm and closely appressed endophragm, varies from planar to pointed and is beset with grana and scattered verrucae. The thickened periphragm may be spongeous (commonly), solid, fenestrate, or fibrous and is commonly drawn out into two short antapical horns (e.g., Pl. 6, Figs 1, 5; Text-fig. 9E), is bilobate (e.g., Pl. 6, Figs 3, 4; Text-fig. 9C), or forms an antapical boss as in Pl. 6, Figs 7, B and Text-fig. 9D. The nature of the archeopyle is generally unclear but appears to involve the loss of one intercalary paraplate (e.g., Pl. 6, Figs 4-6; Text-fig. 9A). The autophragm is commonly torn around the intercalary paraplates; in several specimens this tearing gives the impression of a larger archeopyle involving more than one intercalary paraplate. In some specimens, the anterior half of the epicyst has broken away and these specimens can superficially resemble cysts with apical archeopyles. However, the tears are commonly located close to the paracingulum and appear to have resulted from mechanical damage rather than natural excystment. A small, dark, circular area, up to 4 μm in diameter and located towards the centre of the cyst, may represent an accumulation body.
Dimensions (33 specimens): Total length of cyst (including antapical structure) 115 (134) 155 μm; maximum width of cyst 25 (33) 47 μm; thickness of cyst wall 0.5-1.5 μm.
Holotype: Slide no. 3, EF 533/2. CPC no. 39,159; Pl. 6, Fig. 1. Total length of cyst (including antapical structure) 150 μm; maximum width of cyst 37 μm; thickness of cyst wall 1 μm.
Type locality: Timor Sea, Bayu-Undan Field, Undan-3, core 2 at 3016 m (Elang Formation).
Etymology: Lat., fusticulws (small club); with reference to the club-like outline.
Comparison: Broomea fusticula sp. nov. possesses a rather indistinct paracingulum situated farther from the antapex than is typical of the type species, B. ramosa Cookson & Eisenack 1958. It differs further from the type species and all other members of the genus in bearing only short antapical projections or in lacking them completely. Broomea fusticula is distinguished from species of Imbatodinium Vozzhennikova
emend. Lentin &. Vozzhennikova 1990 and Pareodinia Deflandre emend. Below 1990 by its single, hexagonal, intercalary archeopyle and differentiated antapical sculpture as outlined in the generic discussion. Specimens with a torn or unclear archeopyle margin are thus harder to separate from these genera. Broomea fusticula is distinct from I. kondratjevii Vozzhennikova emend. Lentin & Vozzhennikova 1990 (pp. 88-90; pl. 11; figs 1-4) on account of its larger size (up to 50 μm longer) and less prominent paracingulum. The paracingulum of I. kondratjevii is also nearer to the antapex and is commonly indented. Parker (1986: 164-165; pl. 37, figs 1, 2; text-fig. 5.82) recorded several specimens, from the Upper Jurassic of the Carnarvon Basin, Western Australia, as I. kondratjevii Vozzhennikova emend. Dörhöfer & Davies 1980; these are very similar to B. fusticula in size and structure. Parker noted that 'an archeopyle was not evident on any of the Carnarvon Basin specimens'. However, one of her figured specimens (pl.37, fig. 1; text-fig. 5.82) clearly shows the archeopyle sutures around one, probably two, intercalary paraplates, which suggests a type 2I archeopyle. Parker's specimens differ further from B. fusticula in bearing verrucae on the hypocyst and
coarser grana overall. The cyst length of Pareodinia prochagrinata Below 1990 (p. 69; pl. 15, figs 12, 15, 21, 26, 27) is two-thirds that of B. fusticula but exhibits a similar outline with a narrow antapex. It differs in archeopyle formation (loss of two large intercalary paraplates), in lacking the thickened antapical periphragm, in possessing shagreenate to granulate sculpture that may coalesce to form a reticulum, and in
having a proportionately longer and narrower apical horn.
Local occurrence: Elang Formation; Ternia balmei Interval Zone (Subzone TB4) through Voodooia tabulata Interval Zone (Subzone VT5); rare.
Broomea fusticula Mantle, 2009a, p.44–46, pl.6, figs.1–8; text-fig.9. Holotype: Mantle, 2009a, pl.6, fig.1. Age: Callovian.
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Original description: [Mantle, 2009a]:
Broomea fusticula sp. nov.
Plate 6, Figs 1-8; Text-fig. 9
Diagnosis: Cysts proximate, acavate, elongate-ovoidal, surmounted by a long, slender, apical horn. Antapex densely sculptured with grana and sparse verrucae; irregularly shaped, spongeous phragma commonly extending as 2 short antapical horns or as a thickened, sometimes bilobate, antapical boss. Cyst wall double-layered; endo- and periphragm closely appressed. Periphragm scabrate to granulate with sculpture
coarsening polewards. Paratabulation lacking, other than that suggested by archeopyle outline and paracingular folds. Intercalary archeopyle rarely evident, involving loss of 1 intercalary paraplate.
Description: An elongate, club-like proximate cyst with a long apical horn (up to 65 pm long) and narrow antapex. The scabrate to granulate periphragm is commonly folded, thickened antapically, and may develop low ridges along the paracingulum margins. The broad-based, apical horn tapers uniformly to a rounded tip, which is typically surmounted by a narrow apicular structure. The antapex and distal one-third of the apical horn bear coarser grana than the rest of the cyst. The antapex, formed of thickened periphragm and closely appressed endophragm, varies from planar to pointed and is beset with grana and scattered verrucae. The thickened periphragm may be spongeous (commonly), solid, fenestrate, or fibrous and is commonly drawn out into two short antapical horns (e.g., Pl. 6, Figs 1, 5; Text-fig. 9E), is bilobate (e.g., Pl. 6, Figs 3, 4; Text-fig. 9C), or forms an antapical boss as in Pl. 6, Figs 7, B and Text-fig. 9D. The nature of the archeopyle is generally unclear but appears to involve the loss of one intercalary paraplate (e.g., Pl. 6, Figs 4-6; Text-fig. 9A). The autophragm is commonly torn around the intercalary paraplates; in several specimens this tearing gives the impression of a larger archeopyle involving more than one intercalary paraplate. In some specimens, the anterior half of the epicyst has broken away and these specimens can superficially resemble cysts with apical archeopyles. However, the tears are commonly located close to the paracingulum and appear to have resulted from mechanical damage rather than natural excystment. A small, dark, circular area, up to 4 μm in diameter and located towards the centre of the cyst, may represent an accumulation body.
Dimensions (33 specimens): Total length of cyst (including antapical structure) 115 (134) 155 μm; maximum width of cyst 25 (33) 47 μm; thickness of cyst wall 0.5-1.5 μm.
Holotype: Slide no. 3, EF 533/2. CPC no. 39,159; Pl. 6, Fig. 1. Total length of cyst (including antapical structure) 150 μm; maximum width of cyst 37 μm; thickness of cyst wall 1 μm.
Type locality: Timor Sea, Bayu-Undan Field, Undan-3, core 2 at 3016 m (Elang Formation).
Etymology: Lat., fusticulws (small club); with reference to the club-like outline.
Comparison: Broomea fusticula sp. nov. possesses a rather indistinct paracingulum situated farther from the antapex than is typical of the type species, B. ramosa Cookson & Eisenack 1958. It differs further from the type species and all other members of the genus in bearing only short antapical projections or in lacking them completely. Broomea fusticula is distinguished from species of Imbatodinium Vozzhennikova
emend. Lentin &. Vozzhennikova 1990 and Pareodinia Deflandre emend. Below 1990 by its single, hexagonal, intercalary archeopyle and differentiated antapical sculpture as outlined in the generic discussion. Specimens with a torn or unclear archeopyle margin are thus harder to separate from these genera. Broomea fusticula is distinct from I. kondratjevii Vozzhennikova emend. Lentin & Vozzhennikova 1990 (pp. 88-90; pl. 11; figs 1-4) on account of its larger size (up to 50 μm longer) and less prominent paracingulum. The paracingulum of I. kondratjevii is also nearer to the antapex and is commonly indented. Parker (1986: 164-165; pl. 37, figs 1, 2; text-fig. 5.82) recorded several specimens, from the Upper Jurassic of the Carnarvon Basin, Western Australia, as I. kondratjevii Vozzhennikova emend. Dörhöfer & Davies 1980; these are very similar to B. fusticula in size and structure. Parker noted that 'an archeopyle was not evident on any of the Carnarvon Basin specimens'. However, one of her figured specimens (pl.37, fig. 1; text-fig. 5.82) clearly shows the archeopyle sutures around one, probably two, intercalary paraplates, which suggests a type 2I archeopyle. Parker's specimens differ further from B. fusticula in bearing verrucae on the hypocyst and
coarser grana overall. The cyst length of Pareodinia prochagrinata Below 1990 (p. 69; pl. 15, figs 12, 15, 21, 26, 27) is two-thirds that of B. fusticula but exhibits a similar outline with a narrow antapex. It differs in archeopyle formation (loss of two large intercalary paraplates), in lacking the thickened antapical periphragm, in possessing shagreenate to granulate sculpture that may coalesce to form a reticulum, and in
having a proportionately longer and narrower apical horn.
Local occurrence: Elang Formation; Ternia balmei Interval Zone (Subzone TB4) through Voodooia tabulata Interval Zone (Subzone VT5); rare.