Back
Batioladinium delicatum
Plate 5, Figures 11, 13-16
Holotype: Plate 5, Figure 13, 14
Paratype: Plate 5, Figure 11
Type Locality: late Hauterivian, Speeton Clay Formation,
Speeton. Holotype: Slide lr.C8B/3, E.F. J55.1. Paratype: Slide lr.C8B/2, E.F. L42.1.
Derivation of Name: From the Latin delicatus, delicate - in reference to the thin-walled, insubstantial nature of this species.
Diagnosis: An elongate pareodinioid dinocyst with a long, sharply-tapering apical horn and two fairly long, slender, pointed antapical horns which are of equal length and which are laterally fused close to the antapex. The archeopyle is apical, leaving a shallow sulcal notch on opercular detachment. The cyst wall is very thin and has a very finely granular to microreticulate texture which extends evenly over the whole cyst, including the horns.
Dimensions: Holotype (operculum detached): Length – 86 μm.
Width: 43 μm
Antapical horns: 22 μm
Paratype (complete): Length – 106 μm. Width – 38 μm
Apical horn: 28 μm
Antapical horns (one detached): 16 μm
Overall (operculum detached): 86 (80) 76 μm × 43 (37) 33 μm
Antapical horns: 22 (19) 16 μm
Specimens Measured: 4
Remarks: This thin-walled, delicate species has a very short range, being observed only in Speeton Beds C8B and C8A (early Hauterivian, top regale Zone) and as a single ocurrence at 9467.60 ftMD in well 14/19-E5Y. Only four specimens were recorded at outcrop but despite this rarity, it is felt sufficiently distinctive to include here. Folding and breakage were observed in two of the specimens of Batioladinium delicatum recorded here, suggesting a propensity to physical damage.
Batioladinium delicatum resembles Batioladinium shaftesburiense Nøhr-Hansen 1993, a boreal species ranging no older than the middle Albian (Nøhr-Hansen, et al. 2020), which differs in possessing longer horns (especially the apical), a smoother test surface and no proximal fusing of antapical horns.
Proximal fusing of antapical horns was described for the early Valanginian species Batioladinium natator Duxbury 2018, but that species is much more robust and has shorter antapical horns. Also, the surface ornament of B. natator is scabrate to granular, of varying height and generally more pronounced on the hypocyst and the operculum. Alignment of surface ornament often outlines the cingulum in B. natator, but not in B. delicatum.
Batioladinium longicornutum (Alberti 1961) Brideaux 1975, another long-horned species, is much longer, more slender and thicker-walled than B. delicatum. It is completely smooth (Harding 1980, p. 46) and the antapical horns, although well-developed and of approximately equal length, usually carry ragged ornament (see Plate 5, Fig. 8).
Batioladinium mucronatum n. sp. is of similar width to B. delicatum, but much longer and whereas the antapical horns of B. delicatum appear to be hollow, proximally fused and gradually tapering, those of B. mucronatum are proximally distinct, more complex (see below) and distally solid. In addition, the rounded antapex of B. deliatum contrasts with the strongly concave antapex of B. mucronatum.
Holotype: Plate 5, Figure 13, 14
Paratype: Plate 5, Figure 11
Type Locality: late Hauterivian, Speeton Clay Formation,
Speeton. Holotype: Slide lr.C8B/3, E.F. J55.1. Paratype: Slide lr.C8B/2, E.F. L42.1.
Derivation of Name: From the Latin delicatus, delicate - in reference to the thin-walled, insubstantial nature of this species.
Diagnosis: An elongate pareodinioid dinocyst with a long, sharply-tapering apical horn and two fairly long, slender, pointed antapical horns which are of equal length and which are laterally fused close to the antapex. The archeopyle is apical, leaving a shallow sulcal notch on opercular detachment. The cyst wall is very thin and has a very finely granular to microreticulate texture which extends evenly over the whole cyst, including the horns.
Dimensions: Holotype (operculum detached): Length – 86 μm.
Width: 43 μm
Antapical horns: 22 μm
Paratype (complete): Length – 106 μm. Width – 38 μm
Apical horn: 28 μm
Antapical horns (one detached): 16 μm
Overall (operculum detached): 86 (80) 76 μm × 43 (37) 33 μm
Antapical horns: 22 (19) 16 μm
Specimens Measured: 4
Remarks: This thin-walled, delicate species has a very short range, being observed only in Speeton Beds C8B and C8A (early Hauterivian, top regale Zone) and as a single ocurrence at 9467.60 ftMD in well 14/19-E5Y. Only four specimens were recorded at outcrop but despite this rarity, it is felt sufficiently distinctive to include here. Folding and breakage were observed in two of the specimens of Batioladinium delicatum recorded here, suggesting a propensity to physical damage.
Batioladinium delicatum resembles Batioladinium shaftesburiense Nøhr-Hansen 1993, a boreal species ranging no older than the middle Albian (Nøhr-Hansen, et al. 2020), which differs in possessing longer horns (especially the apical), a smoother test surface and no proximal fusing of antapical horns.
Proximal fusing of antapical horns was described for the early Valanginian species Batioladinium natator Duxbury 2018, but that species is much more robust and has shorter antapical horns. Also, the surface ornament of B. natator is scabrate to granular, of varying height and generally more pronounced on the hypocyst and the operculum. Alignment of surface ornament often outlines the cingulum in B. natator, but not in B. delicatum.
Batioladinium longicornutum (Alberti 1961) Brideaux 1975, another long-horned species, is much longer, more slender and thicker-walled than B. delicatum. It is completely smooth (Harding 1980, p. 46) and the antapical horns, although well-developed and of approximately equal length, usually carry ragged ornament (see Plate 5, Fig. 8).
Batioladinium mucronatum n. sp. is of similar width to B. delicatum, but much longer and whereas the antapical horns of B. delicatum appear to be hollow, proximally fused and gradually tapering, those of B. mucronatum are proximally distinct, more complex (see below) and distally solid. In addition, the rounded antapex of B. deliatum contrasts with the strongly concave antapex of B. mucronatum.