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Species Tenuitella patefacta Li 1987 | ||||||
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| Diagnosis / Definition: | ||||||
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Pearson et al. (2006): DESCRIPTION. Type of wall: Microperforate, surface smooth to finely pustulose, pustules irregularly scattered on umbilical and spiral sides of test. 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. Size: Holotype maximum diameter: 0.16 mm. |
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| Discussion / Comments: | ||||||
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Pearson et al. (2006): DISTINGUISHING FEATURES.- 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. 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. 16-1 8) 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 (1 991) as T. gemma (reillustrated 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 (1 987) 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 P1. 16.7, Figs. 11-12) is reassigned to T. patefacta because of its relatively lobate equatorial outline and more open umbilicus. PHYLOGENETIC RELATIONSHIPS - Descended from T. insolita during the late Eocene; ancestral to T. gemma, which first appeared during the latest Eocene. STRATlGRAPHlC RANGE.- Upper Eocene; Zone E15 to E16. GEOGRAPHIC DISTRIBUTTON .- Few records of this species have been published. Identified in upper Eocene sediments from the Atlantic coastal plain and the southern Indian Ocean. STABLE ISOTOPE PALEOBIOL0GY.- No data available. REPOSITORY.- Holotype and paratypes deposited in the British Museum of Natural History, London. |
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| Systematics: | ||||||
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35 Ordo Foraminiferida Superfamilia Globigerinaceae Familia Cassigerinellidae Genus Tenuitella Species Tenuitella patefacta |
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| Synonym list: | ||||||
| Pearson et al. (2006): 1987 Praetenuitella patefacta Li. - Li : p.309 pl. 1; fig. 6-10 [upper Eocene, Zone P16-P17, Choctaw County,
Alabama, USA]
1988 Globorotalia gemma Jenkins. - Poore & Bybell : p.16 pl. 3; fig. 1-6 [upper Eocene Turborotalia cunialensis Zone,
ACGS #4 borehole, Cape May, New Jersey Coastal
Plain]; [Not Jenkins, 1966]
1991 Tenuitella gemma Jenkins. - Huber : p.441 pl. 7; fig. 7-8 [lower Oligocene, ODP Site 744, Kerguelen
Plateau, southern Indian Ocean];
[Not Jenkins, 1966]
1995 Praetenuitella patefacta Li. - Poag & Commeau : pl. 9; fig. 18-20 [Upper Eocene, Zone P15, Exmore Core, Accomomack
County, Virginia]
1995 Praetenuitella patefacta Li. - Li et al. : p. 132-133 pl. 4; fig. 4-5 [upper Eocene, ODP Hole 749B, Kerguelen Plateau,
southern Indian Ocean]
1995 Praetenuitella insolita Jenkins. - Li et al. : pl. 4; fig. 6-8 [Upper Eocene, ODP Hole 749B, Kerguelen Palteau,
southern Indian Ocaean];
[Not Jenkins, 1966]
2006 Tenuitella patefacta Li. - Pearson et al. : p.497 pl. 16.7; fig. 1-14 (Pl. 16.7, Figs. 1, 2: SEMs of holotype of
Praetenuitella patefacta Li)
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| References: | ||||||
Li,Q. (1987): Poore,R.Z. and Bybell,L.. (1988): Huber,B.T. (1991): Poag,C.W.. and Commeau,J.A.. (1995): Li,Q.; McGowran,B. and Boersma,A. (1995): Pearson,P.N.; Olsson,R.K.; Hemleben,C.; Huber,B.T. and Berggren,W.A. (2006): |
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| Anonymous: Unedited TaxonConcept data | ||||||
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