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Pyxidinopsis fragilis
Plate 6, Figures 11-13, 15, 16 19, 20, 23, 24
?Pyxidinopsis sp. 1 LEEREVELD 1997, p. 452, text-fig. 9g
Holotype: Plate 6, Figures 16, 20
Type Locality: Division C7C, early Hauterivian, inversum ammonite Zone, Speeton Clay, Speeton, England. Holotype: Slide Lr.C7C(4). E.F. P47.0.
Derivation of Name: From the Latin fragilis, easily broken - in reference to the delicate nature of this species.
Diagnosis: A medium-sized, thin-walled, ovoidal dinocyst, which is smooth and covered in a reticulum of small mesh size which is surmounted by rows of minute spines. The reticulum is often partially disorganised into separate or intermittently linked low ridges. The archeopyle is single-plate precingular.
Dimensions: Holotype: Length - 61 μm. Width - 56 μm.
Overall: 71 (58) 51 μm × 56 (52) 48 μm.
Specimens Measured: 5.
Remarks: This rare species is thin-walled and tends to be folded or broken to varying degrees. In size, it is similar to Pyxidinopsis challengerensis Habib 1976, but differs in possessing tiny spines which run along the often partial reticulum. Pyxidinopsis fragilis n. sp. is significantly larger than Pyxidinopsis rigida n. sp. and Pyxidinopsis minuta Duxbury 2018, and has a much thinner cyst wall than the former. Leereveld’s Pyxidinopsis sp. 1 (Leereveld 1997, p. 452, text-fig. 9g) appears to be very similar to Pyxidinopsis fragilis n. sp., in its, “finely reticulate and dense irregularly rugulate ornamentation and in its size, although its characteristic, “indication of the paracingulum (parallel alignment of granules)” was not a feature observed in P. fragilis. This species has a very restricted range at Speeton, between Beds C7C and C7B (upper inversum ammonite Zone, immediately below the early/late Hauterivian boundary). Leereveld’s Pyxidinopsis sp. 1 has a longer range, through much of the Hauterivian.
?Pyxidinopsis sp. 1 LEEREVELD 1997, p. 452, text-fig. 9g
Holotype: Plate 6, Figures 16, 20
Type Locality: Division C7C, early Hauterivian, inversum ammonite Zone, Speeton Clay, Speeton, England. Holotype: Slide Lr.C7C(4). E.F. P47.0.
Derivation of Name: From the Latin fragilis, easily broken - in reference to the delicate nature of this species.
Diagnosis: A medium-sized, thin-walled, ovoidal dinocyst, which is smooth and covered in a reticulum of small mesh size which is surmounted by rows of minute spines. The reticulum is often partially disorganised into separate or intermittently linked low ridges. The archeopyle is single-plate precingular.
Dimensions: Holotype: Length - 61 μm. Width - 56 μm.
Overall: 71 (58) 51 μm × 56 (52) 48 μm.
Specimens Measured: 5.
Remarks: This rare species is thin-walled and tends to be folded or broken to varying degrees. In size, it is similar to Pyxidinopsis challengerensis Habib 1976, but differs in possessing tiny spines which run along the often partial reticulum. Pyxidinopsis fragilis n. sp. is significantly larger than Pyxidinopsis rigida n. sp. and Pyxidinopsis minuta Duxbury 2018, and has a much thinner cyst wall than the former. Leereveld’s Pyxidinopsis sp. 1 (Leereveld 1997, p. 452, text-fig. 9g) appears to be very similar to Pyxidinopsis fragilis n. sp., in its, “finely reticulate and dense irregularly rugulate ornamentation and in its size, although its characteristic, “indication of the paracingulum (parallel alignment of granules)” was not a feature observed in P. fragilis. This species has a very restricted range at Speeton, between Beds C7C and C7B (upper inversum ammonite Zone, immediately below the early/late Hauterivian boundary). Leereveld’s Pyxidinopsis sp. 1 has a longer range, through much of the Hauterivian.