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Phoberocysta latissima
Plate 16, Figures 1, 2, 5
?Phoberocysta neocomica Alberti 1961. – MILLIOUD 1969, pl. 2, fig. 4,
pl. 3, fig. 4.
?Muderongia tomaszowensis Alberti 1961. – MONTEIL 1991, pl. 9, fig.
4 only.
Holotype: Plate 16, Figure 2.
Paratype: Plate 16, Figure 1.
Type Locality: Vergol outcrop, early Valanginian, Bed V31M, pertransiens ammonite Zone, salinarium Sub-zone. Holotype: Slide V31M/3, E.F. H47.0. Paratype: Slide V31M/3, E.F. M46.1.
Derivation of Name: From the Latin latissima, very wide.
Diagnosis: A large, smooth, proximochorate cyst with two wall layers clearly represented. Four long, slender horns of approximately equal length are present, including an apical, two equal laterals and a left antapical. The laterals are distally notched with short postcingular projections. A rudimentary right antapical horn may also be present. Tabulation is marked only by the zigzag apical archeopyle margin. The endocyst is diamond-shaped and clearly defined, with rounded apices. Acuminate, capitate or briefly furcate spines of moderate length cover the cyst surface. The operculum is usually retained.
Dimensions: Holotype: Length - 144 μm. Width - 119 μm. Paratype: Length - 144 μm. Width - 114 μm. Both are complete specimens. Overall - Complete specimens: 144 (142) 132 μm × 127 (115) 101 μm (5 specimens). Operculum detached: 104 (88) 81 μm × 122 (116) 104 μm (6 specimens).
Remarks: This species possesses significantly longer, more slender horns than other members of this genus. The very wide morphological range currently included in Phoberocysta neocomica does include some morphotypes with fairly long horns, but the essentially cruciform nature of P. latissima falls outside the range. Gocht (1957) described several "forma" of Wetzeliella ? neocomica - now Phoberocysta neocomica (Gocht 1957) Millioud 1969, including Wetzeliella? neocomica forma cruciformis, and this appears to be the closest morphologically to P. latissima. All of Gocht's "formae" were incorporated into Phoberocysta neocomica by Millioud (1969, p. 432), and this was further formalised by Lentin and Williams (1973) who listed them as subspecies of P. neocomica. Subsequently, by implication in Monteil (1991, p. 477), Wetzeliella? neocomica forma cruciformis was listed as a taxonomic junior synonym of Phoberocysta neocomica.
In his treatment of "Wetzeliella ? neocomica forma cruciformis", Gocht (1957, p. 176) described a diamond-shaped test with well-developed horns at the poles, features in common with P. latissima. However, he also described, "somewhat squat" lateral horns, with, "one of them often inclined forward" and an inner body, "somewhat hinted at". This contrasts with the long lateral horns and clearly-defined endocyst of P. latissima. In addition, Gocht (op. cit.) described, "a weak transverse structure" (Gocht op. cit., fig. 10), again not observed in P. latissima.
In the present study, Phoberocysta latissima was largely restricted to the early Valanginian, ranging consistently between Beds V10M (pertransiens Zone, salinarium Sub-zone) and V82M (neocomiensis Zone, campylotoxus Sub-zone). A major increase in this species was recorded between Beds V26M and V36M, peaking at the higher level where it was abundant. It is therefore particularly characteristic of the upper part of the salinarium Sub-zone.
Further occurrences of Phoberocysta latissima were noted as isolated occurrences in La Charce Beds LCH206M and LCH220M, both in the early Hauterivian, radiatus ammonite zone. The apparently damaged specimen figured as Muderongia tomaszowensis Alberti 1961 by Monteil (1991, pl. 9, fig. 4), from the pertransiens Zone of southeastern France might also be assignable to P. latissima, as might that specimen from the upper Hauterivian at Angles (SE France) figured as Phoberocysta neocomica in Millioud 1969, pl. II, fig. 4, pl. III, fig. 4.
?Phoberocysta neocomica Alberti 1961. – MILLIOUD 1969, pl. 2, fig. 4,
pl. 3, fig. 4.
?Muderongia tomaszowensis Alberti 1961. – MONTEIL 1991, pl. 9, fig.
4 only.
Holotype: Plate 16, Figure 2.
Paratype: Plate 16, Figure 1.
Type Locality: Vergol outcrop, early Valanginian, Bed V31M, pertransiens ammonite Zone, salinarium Sub-zone. Holotype: Slide V31M/3, E.F. H47.0. Paratype: Slide V31M/3, E.F. M46.1.
Derivation of Name: From the Latin latissima, very wide.
Diagnosis: A large, smooth, proximochorate cyst with two wall layers clearly represented. Four long, slender horns of approximately equal length are present, including an apical, two equal laterals and a left antapical. The laterals are distally notched with short postcingular projections. A rudimentary right antapical horn may also be present. Tabulation is marked only by the zigzag apical archeopyle margin. The endocyst is diamond-shaped and clearly defined, with rounded apices. Acuminate, capitate or briefly furcate spines of moderate length cover the cyst surface. The operculum is usually retained.
Dimensions: Holotype: Length - 144 μm. Width - 119 μm. Paratype: Length - 144 μm. Width - 114 μm. Both are complete specimens. Overall - Complete specimens: 144 (142) 132 μm × 127 (115) 101 μm (5 specimens). Operculum detached: 104 (88) 81 μm × 122 (116) 104 μm (6 specimens).
Remarks: This species possesses significantly longer, more slender horns than other members of this genus. The very wide morphological range currently included in Phoberocysta neocomica does include some morphotypes with fairly long horns, but the essentially cruciform nature of P. latissima falls outside the range. Gocht (1957) described several "forma" of Wetzeliella ? neocomica - now Phoberocysta neocomica (Gocht 1957) Millioud 1969, including Wetzeliella? neocomica forma cruciformis, and this appears to be the closest morphologically to P. latissima. All of Gocht's "formae" were incorporated into Phoberocysta neocomica by Millioud (1969, p. 432), and this was further formalised by Lentin and Williams (1973) who listed them as subspecies of P. neocomica. Subsequently, by implication in Monteil (1991, p. 477), Wetzeliella? neocomica forma cruciformis was listed as a taxonomic junior synonym of Phoberocysta neocomica.
In his treatment of "Wetzeliella ? neocomica forma cruciformis", Gocht (1957, p. 176) described a diamond-shaped test with well-developed horns at the poles, features in common with P. latissima. However, he also described, "somewhat squat" lateral horns, with, "one of them often inclined forward" and an inner body, "somewhat hinted at". This contrasts with the long lateral horns and clearly-defined endocyst of P. latissima. In addition, Gocht (op. cit.) described, "a weak transverse structure" (Gocht op. cit., fig. 10), again not observed in P. latissima.
In the present study, Phoberocysta latissima was largely restricted to the early Valanginian, ranging consistently between Beds V10M (pertransiens Zone, salinarium Sub-zone) and V82M (neocomiensis Zone, campylotoxus Sub-zone). A major increase in this species was recorded between Beds V26M and V36M, peaking at the higher level where it was abundant. It is therefore particularly characteristic of the upper part of the salinarium Sub-zone.
Further occurrences of Phoberocysta latissima were noted as isolated occurrences in La Charce Beds LCH206M and LCH220M, both in the early Hauterivian, radiatus ammonite zone. The apparently damaged specimen figured as Muderongia tomaszowensis Alberti 1961 by Monteil (1991, pl. 9, fig. 4), from the pertransiens Zone of southeastern France might also be assignable to P. latissima, as might that specimen from the upper Hauterivian at Angles (SE France) figured as Phoberocysta neocomica in Millioud 1969, pl. II, fig. 4, pl. III, fig. 4.