pforams@mikrotax - Chiloguembelina adriatica pforams@mikrotax - Chiloguembelina adriatica

Chiloguembelina adriatica

Classification: pf_cenozoic -> Guembelitrioidea -> Chiloguembelinidae -> Chiloguembelina -> Chiloguembelina adriatica
Sister taxa: C. adriatica, C. cubensis, C. andreae, C. ototara ⟩⟨ C. parallela, C. trinitatensis, C. wilcoxensis, C. crinita ⟩⟨ C. subtriangularis, C. midwayensis, C. morsei, C. sp.


Citation: Chiloguembelina adriatica Premec Fucek, Hernitz Kucenjak,&Huber, in Premec Fucek et al. 2018
taxonomic rank: species
Taxonomic discussion:

The exceptionally well-preserved material from the Adriatic Sea and Syria enabled detailed study of the abundant biserial planktonic foraminifera. Two morphologically significant groups with costate surface ornamentation that clearly differ in shape have been observed. The first of these is the commonly identified species C. cubensis. The other group differs from C. cubensis by the growth rate of chambers, total number of chambers, apical angle and length and width of the test. The specimens with a more rapidly flaring test outline are placed in Chiloguembelina adriatica. This species appears in the uppermost Eocene Zone E16 and disappears at the end of Zone O4, with sporadic occurrences in Zone O5. In contrast, Chiloguembelina cubensis has a longer stratigraphic range with its lowest occurrence (LO) in the middle Eocene and highest common occurrence (HCO) at the top of Zone O4, above which it becomes rare and sporadic up to the uppermost Oligocene. [Premec Fucek et al. 2018] 

Catalog entries: Chiloguembelina adriatica

Type images:

Distinguishing features:
Parent taxon (Chiloguembelina): Test subtriangular in outline, biserial throughout or rarely with multiserial final chambers; aperture a simple arched opening at base of the final chamber, with a narrow rim on one margin and a broad collar or flange directed toward one of the flat sides of the test, lacking an infolded margin or internal plate. Rarely with multiple apertures.
This taxon: Like C. cubensis but test outline more rapidly flaring, greater apical angle of about 55-60°, a more rapid increase in chamber size and generally a shorter and wider test.

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.


Test biserial, elongate, subtriangular in outline, periphery rounded; chambers increasing moderately to rapidly in size, usually 11-12, up to 14 in adult specimens; sutures depressed, perpendicular to slightly oblique to the growth axis; aperture a low, moderately narrow to broad, symmetrical arch centered or slightly off-center from the base of the final chamber, bordered on one side by a narrow collar that thickens away from its attachment point on the chamber face. Apical angle is larger than in C. cubensis, generally about 55-60°. [Premec Fucek et al. 2018]

Wall type:
Microperforate, bilamellar, the wall is 4-5 μm thick, the inner layer is usually very thin (0.4-0.5 μm), the outer layer has a submicron granular (blocky) texture (Pl. 17.1, Fig. 21), ototara-type wall (see Chapter 15, this volume); surface ornamentation consists of fine but distinct, discontinuous costae on the youngest chambers, becoming faint on last chambers, with costae aligned with the long axis of the test; the wall is evenly perforated by pores that are usually about 0.50-0.75 μm in diameter, but can exceed 1 μm as a result of dissolution, pore channels are straight. [Premec Fucek et al. 2018]

Size of measured populations: Mid-latitude (Adriatic Sea): Length 0.10-0.19 mm; width 0.07-0.13 mm; breadth 0.06-0.07 mm. Low latitude (Syria): Length 0.14-0.22 mm; width 0.09-014 mm; breadth 0.07-0.08 mm. [Premec Fucek et al. 2018]

Character matrix
test outline:Triangularchamber arrangement:Biserialedge view:Equally biconvexaperture:Interiomarginal
sp chamber shape:Globularcoiling axis:N/Aperiphery:N/Aaperture border:Thin lip
umb chbr shape:Globularumbilicus:N/Aperiph margin shape:Broadly roundedaccessory apertures:None
spiral sutures:Moderately depressedumb depth:N/Awall texture:Finely costateshell porosity:Microperforate: <1µm
umbilical or test sutures:Moderately depressedfinal-whorl chambers:2-2 N.B. These characters are used for advanced search. N/A - not applicable

Biogeography and Palaeobiology

Geographic distribution

Cosmopolitan. Beckmann (1957:89, text-fig. 14:7, 8) was the first to illustrate biserial morphotypes with a costate surface based on two morphotypes from lower Oligocene sediments (Cipero Formation) in Trinidad. Morphotypes with a shorter and wider test and greater apical angle most probably belong to the herein described species C. adriatica n. sp. Hornibrook (1990:368, pl. 1, fig. 1) also figured costate specimens from the lower Oligocene of Cuba, and Leckie and others (1993; pl. 1, fig. 14) provided SEM images of the same morphotype from lower Oligocene of the Ontong Java Plateau. In the Adriatic Sea and Syria this form is very common in Zone O1 and O2 and comprises up to 30% of the biserial planktonic populations in the small size fractions (63-125 μm). [Premec Fucek et al. 2018]

Isotope paleobiology
No data available. [Premec Fucek et al. 2018]

Phylogenetic relations
Probably evolved from C. cubensis during the latest Eocene. [Premec Fucek et al. 2018]

Most likely ancestor: Chiloguembelina cubensis - at confidence level 2 (out of 5). Data source: Premec Fucek et al. 2018.

Biostratigraphic distribution

Geological Range:
Notes: Uppermost Eocene (Zone E16) to the end of Zone O4, with sporadic occurrences in Zone O5 (this study). [Premec Fucek et al. 2018] [Premec Fucek et al. 2018]
Last occurrence (top): within O5 zone (26.93-28.09Ma, top in Chattian stage). Data source: Premec Fucek et al. 2018
First occurrence (base): within E16 zone (33.90-34.68Ma, base in Priabonian stage). Data source: Premec Fucek et al. 2018

Plot of occurrence data:

Primary source for this page: Premec Fucek et al. 2018 - Olig Atlas chap.17 p.463


Beckmann, J. P. (1957). Chiloguembelina Loeblich and Tappan and related foraminifera from the Lower Tertiay 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: 83-95. gs

Hernitz Kucenjak, M., Premec Fucek, V., Slavkovic, R. & Mesic, I. A. (2006). Planktonic foraminiferal biostratigraphy of the late Eocene and Oligocene in the Palmyride area, Syria. Geologia Croatica. 59: 19-39. gs

Hornibrook, N. d. B. (1990). Chiloguembelina cubensis (Palmer) and C. ototara (Finlay), in New Zealand. Journal of Foraminiferal Research. 20(4): 368-371. gs

Leckie, R. M., Farnham, C. & Schmidt, M. G. (1993). Oligocene planktonic foraminifer biostratigraphy of Hole 803D (Ontong Java Plateau) and Hole 628A (Little Bahama Bank), and comparison with the southern high latitudes. Proceedings of the Ocean Drilling Program, Scientific Results. 130: 113-136. gs

Palmer, D. K. (1934). The Foraminiferal Genus Guembelina in the Tertiary of Cuba. Memorias de la Sociedad Cubana de Historia Natural “Felipe Poey”. 8(2): 73-76. gs

Premec Fucek, V., Hernitz Kucenjak, M. & Huber, B. T. (2018). Taxonomy, biostratigraphy, and phylogeny of Oligocene Chiloguembelina and Jenkinsina. 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 17): 459-480. gs

Spezzaferri, S. & Premoli Silva, I. (1991). Oligocene planktonic foraminiferal biostratigraphy and paleoclimatic interpretation from Hole 538A, DSDP Leg 77, Gulf of Mexico. Palaeogeography Palaeoclimatology Palaeoecology. 83: 217-263. gs


Chiloguembelina adriatica compiled by the pforams@mikrotax project team viewed: 17-7-2024

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