Tenuitella patefacta


Classification: pf_cenozoic -> Globigerinitidae -> Tenuitella -> Tenuitella patefacta
Sister taxa: T. iota, T. fleisheri, T. parkerae, T. clemenciae, T. angustiumbilicata, T. munda, T. gemma, T. praegemma, T. patefacta, T. insolita, T. sp.,

Taxonomy

Citation: Tenuitella patefacta Li 1987
Rank: Species
Basionym: Praetenuitella patefacta
Synonyms:
Taxonomic discussion: Comparison of the test outline, umbilical morphology, and height of the aperture in the T. patefacta holotype (re-illustrated on Pl. 16.7, Figs. 1-2) with those features on the holotype of T. gemma (Pl.16.7, Figs. 16-18) and illustrations of T. insolita (Pl.16.5) reveals why Li (1987) considered patefacta to be the intermediate link between insolita and gemma. Specimens designated as Praetenuitella patefacta by Poag and Commeau (1995) (re-illustrated on Pl. 16.7, Figs. 3-5) have a more circular aperture and a more closed umbilicus than Li’s primary type specimens but still fall within Li’s species concept. An early Oligocene specimen designated by Huber (1991) as T. gemma (re-illustrated on Pl. 16.7: Figs. 9-10) is too deeply umbilicate for that species and is reassigned to T. patefacta despite having a narrower and deeper umbilicus than found in Li’s (1987) type specimen. This latter specimen is nearly identical to a specimen assigned to T. patefacta from the upper Eocene specimen from the New Jersey Coastal Plain (Pl.16.7, Figs. 6-8). A specimen previously assigned to T. praegemma forma typica by Poag and Commeau (1995) (see Pl. 16.7, Figs. 13-14) is here considered to be T. patefacta because of its more highly arched aperture, but the more pendulous and axially broadening of the chambers and more closed umbilicus are suggestive of T. praegemma. A specimen designated as Globorotalia gemma by Poore and Bybell (1988; re-illustrated on Pl. 16.7, Figs. 11-12) is reassigned to T. patefacta because of its relatively lobate equatorial outline and more open umbilicus. [Huber et al. 2006]

Catalog entries: Praetenuitella patefacta

Type images:

Distinguishing features: Like T. insolita but with a low rather than highly arched, extraumbilical aperture

NB These concise distinguishing features statements are used in the tables of daughter-taxa to act as quick summaries of the differences between e.g. species of one genus.
They are being edited as the site is developed and comments on them are especially welcome.

Description


Diagnostic characters: Differs from Tenuitella insolita by having a low rather than highly arched, extraumbilical aperture; differs from T. gemma by having a more lobate equatorial outline and a more oval equatorial outline, a more open umbilicus and an aperture that extends closer to the peripheral margin; differs from T. praegemma by lacking secondary apertures or apertural lips and having globular rather than oval or subcrescentic chambers. [Huber et al. 2006]

Wall type: Microperforate, surface smooth to finely pustulose, pustules irregularly scattered on umbilical and spiral sides of test. [Huber et al. 2006]

Test morphology: Test small, lobate circular in equatorial outline, equatorial periphery rounded; chambers globular, coiled in a very low trochospire, increasing gradually in size, 5-6 in the final whorl, nearly symmetrical in edge view; sutures depressed, curved on the spiral side, radial on umbilical side; umbilicus small; aperture a low extraumbilical-umbilical arch bordered by a narrow, equidimensional lip. [Huber et al. 2006]

Size: Holotype maximum diameter: 0.16 mm. [Huber et al. 2006]

Character matrix

test outline:Lobatechamber arrangement:Trochospiraledge view:Equally biconvexaperture:Umbilical-extraumbilical
sp chamber shape:Globularcoiling axis:Very lowperiphery:N/Aaperture border:Thin lip
umb chbr shape:Globularumbilicus:Wideperiph margin shape:Moderately roundedaccessory apertures:None
spiral sutures:Strongly depressedumb depth:Shallowwall texture:Finely pustuloseshell porosity:Microperforate: <1µm
umbilical or test sutures:Strongly depressedfinal-whorl chambers:5.0-6.0 N.B. These characters are used for advanced search. N/A - not applicable

Biogeography and Palaeobiology


Geographic distribution: Few records of this species have been published. Identified in upper Eocene sediments from the Atlantic coastal plain and the southern Indian Ocean. [Huber et al. 2006]

Isotope paleobiology: No data available. [Huber et al. 2006]

Phylogenetic relations: Descended from T. insolita during the late Eocene; ancestral to T. gemma, which first appeared during the latest Eocene. [Huber et al. 2006]

Most likely ancestor: Tenuitella insolita - at confidence level 4 (out of 5). Data source: Huber et al. 2006 f16.2.

Biostratigraphic distribution

Geological Range:
Notes: Upper Eocene; Zone E15 to E16. [Huber et al. 2006]
Last occurrence (top): within E16 zone (33.90-34.68Ma, top in Priabonian stage). Data source: Huber et al. 2006 f16.2
First occurrence (base): within E15 zone (34.68-35.89Ma, base in Priabonian stage). Data source: Huber et al. 2006 f16.2

Plot of occurrence data:

Primary source for this page: Huber et al. 2006 - Eocene Atlas, chap. 16, p. 490

References:

Huber, B. T., Olsson, R. K. & Pearson, P. N. (2006). Taxonomy, biostratigraphy, and phylogeny of Eocene microperforate planktonic foraminifera (Jenkinsina, Cassigerinelloita, Chiloguembelina, Streptochilus, Zeauvigerina, Tenuitella, and Cassigerinella) and Problematica (Dipsidripella). 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 16): 461-508. gs

Jenkins, D. G. (1966b). Planktonic foraminiferal zones and new taxa from the Danian to lower Miocene of New Zealand. New Zealand Journal of Geology and Geophysics. 8: 1088-1126. gs

Li, Q. (1987). Origin, phylogenetic development and systematic taxonomy of the Tenuitella plexus (Globigerinitidae, Globigerininina). Journal of Foraminiferal Research. 17: 298-320. gs

Li, Q., McGowran, B. & Boersma, A. (1995). Early Palaeocene Parvularugoglobigerina and late Eocene Praetenuitella: does evolutionary convergence imply similar habitat?. Journal of Micropalaeontology. 14: 119-134. gs

Poag, C. W. & Commeau, J. A. (1995). Paleocene to middle Miocene planktic foraminifera of the southwestern Salisbury Embayment, Virginia and Maryland: Biostratigraphy, allostratigraphy, and sequence stratigraphy. Journal of Foraminiferal Research. 25: 134-155. gs

Poore, R. Z. & Bybell, L. M. (1988). Eocene to Miocene biostratigraphy of New Jersey Core ACGS #4: Implications for regional stratigraphy. U.S. Geological Survey Bulletin. 1829: 1-41. gs


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Tenuitella patefacta compiled by the pforams@mikrotax project team viewed: 8-12-2019

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