Daughter taxa (time control age-window is: 0-800Ma)
Neogene species
Tenuitella clemenciae Like T. munda but larger, 5 chambers in final whorl, and a more flattened lip
Paleogene species
Tenuitella angustiumbilicata Like Tenuitella gemma but chambers more inflated, especially in edge and umbilical view, and slightly higher trochospiral, and also by typically has 4½ (vs. 5-6) chambers in final whorl. Wall texture is distinctly more pustulose.
Tenuitella munda Very small, low trochospiral, lobate, 4-4½ chambers in final whorl, sutures depressed. Surface fairly smooth with fine pustules; umbilicus narrow; aperture low arch with thin lip
Tenuitella gemma Like T. praegemma but test slightly more compressed, less lobate periphery and nearly closed umbilicus; and by absence of secondary apertures or apertural lips.
Tenuitella praegemma Like T. insolita but aperture is low and extends from near the umbilicus to the spiral side and may be divided in two.
Tenuitella patefacta Like T.insolita but with a low rather than highly arched, extraumbilical aperture
Tenuitella insolita Distinguished from other tenuitellids by its highly arched and narrow aperture and smooth test surface.
Tenuitella sp. Specimens which cannot be assigned to established species
Praetenuitella Li, 1987:309 (type species Praetenuitella praegemma Li, 1987).
Tenuitellinata Li, 1987:311 (type species Globigerina ciperoensis angustiumbilicata Bolli, 1957).
Taxonomic discussion: Li (1987) differentiated Praetenuitella from Tenuitella based on the presence of macroperforations in the early ontogeny and microperforations in later chambers. However, SEM observations of one of the earliest tenuitellids, T. insolita, reveals that early chambers are also microperforate. Thus, recognition of Praetenuitella as a separate genus is no longer considered warranted. SEM observations of pre-ultimate chambers in T. gemma (Pl. 16.7, Fig. 15), T. insolita (Pl 16.4, Fig. 10) and T. praegemma (Pl. 16.5, Fig. 9) reveals the presence of a monolamellar wall microstructure, unlike species assigned to the Globigerinacea. [Huber et al. 2006]
This genus was revised by Huber and others (2006). As in Fleisher’s (1974) original concept, we include forms with an umbilical aperture as well as those with intraumbilical-extraumbilical and wholly extraumbilical apertures, hence we include Li’s (1987) form-genus Tenuitellinata in synonymy (following Pearson and Wade, 2009; see additional discussion under Tenuitella angustiumbilicata). [Pearson et al. 2018]
The diagnostic features common to all species of Tenuitella are that all have a minute to small, low trochospiral test, globular chambers lacking a distinct carina, and a smooth surface penetrated by extremely small perforations, which are usually obscured by small pustules or crystallites (PI. 39, Figs. 1-4). The subgenus Tenuitella can be easily distinguished from other globorotaliids by its characteristic smooth surface and smaller size. [Kennett & Srinivasan 1983]
Distinguishing features: Parent taxon (Globigerinitidae): Microperforate This taxon: Minute to small, low trochospiral test, with globular chambers. Monolamellar, microperforate wall with a smooth or finely pustulate surface.
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
Morphology: Test small, low trochospiral, occasionally becoming pseudoplanispiral, periphery rounded; chambers globular to ovate, 4-6 in final whorl; sutures radial on umbilical side, radial to obliquely curved on spiral side; wall microperforate (glutinata-type), thin, smooth to weakly pustulose; umbilicus small, open to nearly closed; aperture a low extraumbilical to umbilical arch, bordered by a thin lip. [Pearson et al. 2018] Wall type: wall monolamellar, microperforate, thin, smooth to weakly pustulose; [Huber et al. 2006]
glutinata-type [Pearson et al. 2018] Size: Mostly small <150 µm to very small <75 µm. [Pearson et al. 2018]
Biogeography and Palaeobiology
Phylogenetic relationsThe lineage from which tenuitellids descended is uncertain. Li (1987) suggested that Tenuitellaimpariapertura ( =T. insolita), the earliest tenuitellid species, evolved from the bilamellar, normal perforate, and planispirally coiled Pseudohastigerina micra (Cole) during the late Eocene based on the stratigraphic overlap of both species, the nearly peripheral position of the tenuitellid aperture, and the pseudoplanispiral coiling observed in the early tenuitellid ontogeny. However, this is considered unlikely, as it requires too many simultaneous changes in wall texture, chamber morphology, and coiling for a single species transition. Li and McGowran (1996) observed that, except for the trochospiral coiling of T. insolita, this species shares a number of morphological features in common with Cassigerinellaeocaenica (C. winniana in their study), including a smooth, microperforate wall, minute test size, and high, narrowly arched aperture. On this basis, we suggest that the oldest tenuitellid, T. insolita, was derived from C. eocaenica during the late Eocene and we provisionally place Tenuitella together with Cassigerinella in the Cassigerinellidae. An alternative possibility is that these genera should be grouped with the Guembelitriidae because of their similarity with the guembelitriid wall microstructure. Other possiblities for the origin of the tenuitellids also need to be explored. [Huber et al. 2006]
Important Neogene species referable to Tenuitella are T. clemenciae and T. anfracta, which show morphological continuity as a lineage from the Late Oligocene through the Neogene (Text Fig. 18). T. munda exhibits most of its stratigraphic range within the Paleogene. [Kennett & Srinivasan 1983]
Geological Range: Notes: Upper Eocene-upper Oligocene (Zones E15-O6). [Huber et al. 2006] Last occurrence (top): at top of N17b zone (100% up, 5.7Ma, in Messinian stage). Data source: Total of ranges of the species in this database First occurrence (base): within E15 zone (34.68-35.89Ma, base in Priabonian stage). Data source: Total of ranges of species in this database
Plot of occurrence data:
Range-bar - range as quoted above, pink interval top occurs in, green interval base occurs in.
Triangles indicate an event for which a precise placement has been suggested
Primary source for this page: Pearson et al. 2018 - Olig Atlas chap.16 p.443; Huber et al. 2006 - Eocene Atlas, chap. 16, p. 487
References:
Fleisher, R. L. (1974a). Cenozoic planktonic foraminifera and biostratigraphy, Arabian Sea, Deep Sea Drilling Project, Leg 23A. Initial Reports of the Deep Sea Drilling Project. 23: 1001-1072. gsO
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. gsO
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 [1965](6): 1088-1126. gs
Kennett, J. P. & Srinivasan, M. S. (1983). Neogene Planktonic Foraminifera. Hutchinson Ross Publishing Co., Stroudsburg, Pennsylvania. 1-265. gs
Li, Q. & McGowran, B. (1996). The planktonic foraminifer Cassigerinella winniana (Howe) from southern Australia: Comments on its lineage recognition. Revista Española de Micropaleontología. 28: 97-103. gs
Li, Q. (1987). Origin, phylogenetic development and systematic taxonomy of the Tenuitella plexus (Globigerinitidae, Globigerininina). Journal of Foraminiferal Research. 17: 298-320. gs
Pearson, P. N. & Wade, B. S. (2009). Taxonomy and stable isotope paleoecology of well-preserved planktonic foraminifera from the uppermost Oligocene of Trinidad. Journal of Foraminiferal Research. 39: 191-217. gs
Pearson, P. N., Wade, B. S. & Huber, B. T. (2018c). Taxonomy, biostratigraphy, and phylogeny of Oligocene Globigerinitidae (Dipsidripella, Globigerinita, and Tenuitella). 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 16): 429-458. gsO
Srinivasan, M. S. & Kennett, J. P. (1981a). A review of Neogene planktonic foraminiferal biostratigraphy: applications in the equatorial and south Pacific. SEPM Special Publication. 395-432. gs
Tenuitella compiled by the pforams@mikrotax project teamviewed: 5-10-2024
