Daughter taxa (time control age-window is: 0-800Ma) | ||||
acrostoma-incognita group | ||||
Paragloborotalia acrostoma Like P. pseudocontinuosa, but 4½ - 5 chambers and with a higher arched aperture; not very lobulate, often pentagonal in outline. | ||||
Paragloborotalia incognita Like P. nana but larger, and with a more rapid rate of chamber expansion, a less compact test, a higher arched aperture, elongation of the chambers in the direction of coiling, and slightly curved spiral sutures. | ||||
Paragloborotalia pseudocontinuosa Characterized by its spherical chambers that increase moderately rapidly as added. 4 chambers in final whorl | ||||
Paragloborotalia semivera Like P. pseudocontinuosa but somewhat larger and with more chambers (4½-5) in the final whorl. | ||||
pseudokugleri -> kugleri lineage | ||||
Paragloborotalia kugleri Like P. pseudokugleri but the final chamber shows a distinct pinching; the chambers are less inflated and more appressed; the outline is more ovate and less lobulate; spiral side sutures are more strongly curved and less depressed. | ||||
Paragloborotalia pseudokugleri Like P. nana but with 5 or more chambers in the final whorl (typically 6-7) and somewhat less inflated chambers. | ||||
siakensis -> mayeri lineage | ||||
Paragloborotalia mayeri Like P. siakensis but with slightly curved spiral sutures and generally higher arched aperture, and less strongly developed lip. | ||||
Paragloborotalia siakensis Like P. nana but with more chambers (5-7) in the final whorl, less embracing chambers, more rapid rate of chamber expansion, and a higher arched aperture. | ||||
Other species | ||||
Paragloborotalia birnageae 5½-7, typically 6, embracing chambers in the final whorl; last chamber may be kummerform | ||||
Paragloborotalia continuosa Like P. nana but less compact and periphery lobulate; aperture higher arched aperture with a more distinctive lip. | ||||
Paragloborotalia opima Like P. nana but larger (>0.32mm) | ||||
Paragloborotalia nana Test small, compact, quadrangular, usually 4 chambers in the final whorl. Umbilicus very narrow, sutures radial. Aperture with prominent lip, which often obscures the primary aperture. | ||||
Paragloborotalia griffinoides Small, very low trochospiral, compact, subquadrate test. Aperture with a thickened continuous lip. Wall coarsely cancellate. | ||||
Paragloborotalia sp. Specimens which cannot be assigned to established species |
Paragloborotalia experienced considerable evolutionary changes through the Oligocene – middle Miocene, particularly a period of accelerated evolutionary turnover (speciation and extinction) across the Oligocene/Miocene boundary and in the earliest Miocene (Figure 5.1). Major evolutionary trends include: 1) originally 4-5 chambers in the final whorl (ancestral condition), to 6 chambers in the mid- to late Oligocene, and finally up to 7 chambers in the early and middle Miocene; 2) radial spiral sutures through the mid Oligocene (Zone O5; ancestral condition), appearance of slightly curved spiral sutures in the late Oligocene (Zones O6-O7), to more strongly curved spiral sutures in some taxa in the early Miocene (Zone M1) – a trend also noted by Keller (1981); and 3) broadly rounded peripheral margin through the mid-Oligocene (Zone O5; ancestral condition) to some taxa with subacute margins in the late Oligocene and early Miocene. Species of Paragloborotalia range in size from small (0.35 mm) (e.g., Spezzaferri, 1994; Wade and others, 2007, 2016). [Leckie et al. 2018] Kennett and Srinivasan (1983) erected Jenkinsella (type species siakensis) as a subgenus of Globorotalia, for low trochospiral forms with globular to subglobular chambers, a rounded peripheral margin, lacking a distinct carina, with an umbilical-extraumbilical aperture bordered by a rim. Jenkinsella included opima, semivera, siakensis, bella, mayeri and acrostoma. Paragloborotalia was erected by Cifelli in 1982 and therefore has seniority over Jenkinsella, which is here considered a junior synonym. [Leckie et al. 2018] Paragloborotalia is distinguished from Parasubbotina by a slower rate of chamber growth and inflation, more embracing chambers, and generally more heavily encrusted test. [Leckie et al. 2018]
Catalog entries: Paragloborotalia, Jenkinsella
Distinguishing features:
Parent taxon (Globigerinidae): Wall spinose, usually with 3½-6 globular chambers in final whorl, trochospiral or planispiral
This taxon: Very low trochospiral test with low-arched umbilical-extraumbilical aperture with a thick lip; 4-5 chambers in the ultimate whorl, and a coarsely cancellate, sacculifer-type wall.
Morphology:
Wall type:
Geographic distribution
Phylogenetic relations
Most likely ancestor: Parasubbotina - at confidence level 3 (out of 5). Data source: Olsson and others, 2006; Leckie et al. 2018.
Likely descendants: Fohsella; Globorotalia; Neogloboquadrina;
plot with descendants
Geological Range:
Notes: Lower Eocene Zone E7 (Olsson and others, 2006) to Miocene Zone M13. The youngest recorded species attributed to Paragloborotalia is P. continuosa.
Last occurrence (top): at top of M13 zone (100% up, 6.1Ma, in Messinian stage). Data source: Total of ranges of the species in this database
First occurrence (base): within E1 zone (55.81-55.96Ma, base in Ypresian stage). Data source: Total of ranges of species in this database
Plot of occurrence data:
Primary source for this page: Leckie et al. 2018 - Olig Atlas chap.5 p.127 (major revision of Olsson et al. 2006 - Eocene Atlas, chap 5, p. 88)
Blow, W. H. (1979). The Cainozoic Globigerinida: A study of the morphology, taxonomy, evolutionary relationships and stratigraphical distribution of some Globigerinida (mainly Globigerinacea). E. J. Brill, Leiden. 2: 1-1413. gs Bolli, H. M. (1957b). Planktonic foraminifera from the Oligocene-Miocene Cipero and Lengua formations of Trinidad, B.W.I. In, Loeblich, A. R. , Jr., Tappan, H., Beckmann, J. P., Bolli, H. M., Montanaro Gallitelli & E. Troelsen, J. C. (eds) Studies in Foraminifera. U.S. National Museum Bulletin . 215: 97-123. gs Cifelli, R. (1982). Early Occurrences and some Phylogenetic Implications of Spiny, Honeycomb Textured Planktonic Foraminifera. Journal of Foraminiferal Research. 12(2): 105-115. gs Leckie, R. M. et al. (2018). Taxonomy, biostratigraphy, and phylogeny of Oligocene and Lower Miocene Paragloborotalia and Parasubbotina. In, Wade, B. S., Olsson, R. K., Pearson, P. N., Huber, B. T. & Berggren, W. A. (eds) Atlas of Oligocene Planktonic Foraminifera. Cushman Foundation for Foraminiferal Research, Special Publication . 46(Chap 5): 125-178. gs Olsson, R. K., Pearson, P. N. & Huber, B. T. (2006c). Taxonomy, biostratigraphy, and phylogeny of Eocene Catapsydrax, Globorotaloides, Guembelitrioides, Paragloborotalia, Parasubbotina, and Pseudoglobigerinella n. gen. In, Pearson, P. N., Olsson, R. K., Hemleben, C., Huber, B. T. & Berggren, W. A. (eds) Atlas of Eocene Planktonic Foraminifera. Cushman Foundation for Foraminiferal Research, Special Publication . 41(Chap 5): 67-110. gs OReferences:
Paragloborotalia compiled by the pforams@mikrotax project team viewed: 12-11-2024
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