Catalog - Bolliella praeadamsi

CATALOG OF ORIGINAL DESCRIPTIONS: Bolliella praeadamsi Chaproniere 1991

This page provides data from the catalog of type descriptions. The catalog is sorted alphabetically. Use the current identification link to go back to the main database.


Higher levels: pf_cat -> B -> Bolliella -> Bolliella praeadamsi
Other pages this level: B. praeadamsi

Bolliella praeadamsi

Citation: Bolliella praeadamsi Chaproniere 1991
Rank: Species
Type specimens: Holotype and 5 paratypes from sample 81640021, So16-12SL-075, and are filed under numbers CPC30216 30218 and CPC30224-30226 in the Commonwealth Palaeontology Collection, BMR, Canberra.
Type sample (& lithostrat): sample 81640021 from piston core So16-12SL-075
Type age (chronostrat): Pleistocene, N23;
Type locality: Queensland Plateau, piston core (-15N; 147W)
Type repository: Canberra; Commonwealth Palaeontology Collection, BMR,

Current identification:


Original Description


Diagnosis
. A hastigerine with the final 1 to 4 chambers arranged planispirally, and which may or may not show some radial elongation; the earlier part of the final whorl is clearly trochospiral.

Description
. Test medium to large, with 5 or 6 chambers in the final whorl. Initial stage a low trochospire, with the last 1 to 4 chambers planispirally arranged and well separated from the previous whorl. Chambers initially spherical and globular becoming ovate; may finally be radially elongate in large specimens. Chambers increase rapidly in size throughout ontogeny, each separated from the previous chamber by a depressed radial suture. Aperture umbilical-extra-umbilical and a low asymmetrical arch on the earlier chambers of the final whorl, becoming a high and wide symmetrical arch with a distinct thin lip. Wall calcareous, spinose, densely perforate with large circular pores, with randomly distributed, rounded and raised spine bases. Spines round becoming triradiate.

Size:

Etymology:

Extra details from original publication
Remarks. In side view this species is very similar to Bo. calida sensu lato in having a narrow test, but differs by having 14 chambers arranged in a planispire, clearly separated from the previous whorl. In addition, some of the final chambers may show some degree of radial elongation. Bo. praeadami differs from Bo. adamsi in having rounded, subglobular chambers, rather than the pointed distal chamber apex of Bo. adamsi. It differs from Gl. aequilateralis (1) in having only the last few chambers of the test arranged planispirally, with a distinct trochospiral part of the final whorl as viewed from the spiral side, (2) by having more chambers in the final whorl, the earlier part of the test being somewhat narrower in side view, (3) by having the last few chambers separated from the previous whorl, and (4) by having a distinct apertural lip. The chambers of Gl. aequilateralis are more globular and expand more rapidly in diameter as the test increases in size, leading to a thicker test as seen in side view. Saito & others (1981) show that the test wall of Bo. calida is very similar to that of Bo. adamsi, a feature not found in this study. The wall texture of both Bo. adamsi and Bo. praeadamsi is identical, but it has distinctly larger diameter pores than those of Bo. calida. This may be an environmental factor, although specimens illustrated by Saito & others (1981) were collected from the southwestern equatorial Pacific, not far from the present study area.

This species has almost certainly been recorded either as Gl. aequilateralis ( = Gl. siphonifera)or as Bo. adamsi, with which it has many features in common. It is readily differentiated from Gl. aequilateralis in side view. It is very similar to both Bo. calida and Bo. adamsi in side view in its slow rate of chamber expansion, resulting in a lower trochospire than that of Gl. aequilateralis.

Phylogeny. Two phylogenies for the hastigerines have been proposed. Blow (1969) traced the phylogenetic origins of this group to Gl. obesa. He believed that this morphotype graded into the planispiral forms Gl. praesiphonifera (within Zone N.7), Gl. aequilateralis ( = siphonifera)in Zone N. 12, and Bo. adamsi within the Pleistocene (Banner & Blow, 1960). Blow (1969) considered that Bo. calida praecalida had its origins within the Globigerina praebulloides group and gave rise to Bo. calida calida, which is thus unrelated to Hastigerina. H. pelagica was considered to have had an unknown ancestry (Banner & Blow, 1960). Kennett & Srinivasan (1983, text fig. 26) proposed a phylogenetic scheme for the group, with the same lineage (Gl. obesa -  Gl. praesiphonifera - Gl. aequilateralis) as in Banner & Blow (1960). However, H. pelagica and Bo. calida (including both the praecalida and calida morphotypes) were both derived from Gl. aequilateralis (within Zones N . 17A and N. 19, respectively). Srinivasan & Kennett (1975) believed that Bolliella evolved from Globigerinella.

As noted above, the presence of an apertural lip and the arrangement of the initial coil of Bo. calida praecalida, Bo. calida calida, Bo. praeadamsi and Bo. adamsi distinguishes the group from other spinose forms such as Globigerina bulloides, GI. aequilateralis and Hastigerina pelagica. On the basis of wall structure (size and pattern of pores, characteristics of spines and spine bases), the Bo. calida group and Bolliella are close to Gl. aequilateralis, but distinct from Hastigerina. The FAD of Bo. praeadamsi occurs before the FAD of Bo. calida calida, indicating that the latter cannot be the ancestral form. As noted above, the early ontogenetic stage of Bo. praeadamsi is very similar to Bo. calida praecalida, and this appears to be the preferred ancestral form of Bo. praeadamsi.

Editors' Notes

References:

Banner, F. T. & Blow, W. H. (1960b). The taxonomy, morphology and affinities of the genera included in the subfamily Hastigerininae. Micropaleontology. 6(1): 19-31. gs

Chaproniere, G. C. H. (1991). Pleistocene to Holocene planktic foraminiferal biostratigraphy of the Coral Sea, offshore Queensland, Australia. BMR Journal of Australian Geology and Geophysics. 12: 195-221. gs V O

Saito, T., Thompson, P. R. & Breger, D. (1981). Systematic Index of Recent and Pleistocene Planktonic Foraminifera. University of Tokyo Press, Tokyo. 1-190. gs

Srinivasan, M. S. & Kennett, J. P. (1975c). The status of Bolliella, Beella, Protentella and related planktonic foraminifera based on surface ultrastructure. Journal of Foraminiferal Research. 5(3): 155-165. gs


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Bolliella praeadamsi compiled by the pforams@mikrotax project team viewed: 4-10-2022

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