Catalog - Chiloguembelitria biseriata

This page provides data from the catalog of type descriptions. The catalog is sorted alphabetically. Use the current identification link to go back to the main database.

Other pages this level: C. biseriata, C. danica, C. hofkeri, C. trilobata

Chiloguembelitria biseriata

Citation: Chiloguembelitria biseriata Arenillas et al. 2017

Type specimens: Fig. 14(a)e(d); Holotype MPZ 2016/116 (Fig. 14(a)). Paratype MPZ 2016/117 (Fig. 14(b)). MPZ 2016/118 (Fig. 14(c)). Paratype MPZ 2016/119 (Fig. 14(d)).

Type sample (& lithostrat): in the lower part of Zone P1a, or middle part of the Eoglobigerina trivialis Subzone (Parasubbotina pseudobulloides Zone), lower Danian.

Type age (chronostrat): 8.50 m above the Cretaceous/Paleogene boundary of the El Kef section (sample KF20.50),

Type locality: El Kef section, El Haria Formation, Tunisia.

Type repository: Zaragosa; Museo de Ciencias Naturales de la Universidad de Zaragoza (Aragon Government, Spain).

Test subconical to flaring, with 7-10 subspherical chambers and a medium-to-high rate of chamber enlargement. Triserial juvenile stage with 5-6 chambers distributed in 1.5-2 spiral whorls, and biserial final stage with 1-2 pairs of chambers in a twisted plane of biseriality. Outline subtriangular, lobate, with incised sutures. Aperture interiomarginal, lateral, rounded or elongate, generally asymmetrical, with an imperforate lip. Wall surface microperforate, pustulate to rugose, with isolated, decen-tered pore-mounds, perforate and/or imperforate rugosities, and blunt pustules (papilla-type).

Adult size range 120-160 mm in height.

Latin term biseriata referring to the biserial final stage of its ontogeny.

? 1998 Guembelitria danica (Hofker); Jenkins et al., p. 64, part, pl. 1, Fig. 3.
? 1999 Woodringina claytonensis Loeblich and Tappan; Olsson et al., p. 242, pl. 68, Fig. 1.

Remarks. It differs from other Chiloguembelitria species in its final biserial stage. The species Chg. biseriata sp. nov. has previously gone unnoticed because it is morphologically very similar to Woodringina claytonensis. However, W. claytonensis differs in its wall surface (pustulate or muricate rather than rugose, and without pore-mounds) and its reduced triserial initial stage (single whorl of three-chambered stage, usually pseudotriserial rather than triserial). Olsson et al. (1999) included these morphotypes within the phenotypic variability of W. claytonensis, adducing that some specimens of Woodringina bear scattered pore-mounds. However, typical W. claytonensis has a pustulate wall like other species of Woodringina and Chiloguembelina, consisting of small imperforate blunt pustules (papilla-type). Many pustules in the wall of Woodringina may have the same ontogenetic origin as the pore-mounds in Guembelitria, although others perhaps may not.

Occurrence. Lowermost Danian, from the lower part of Zone Pa to the upper part of Zone P1a of Berggren and Pearson (2005), i.e. from the lower part of the Parvularugoglobigerina longiapertura Subzone (Guembelitria cretacea Zone) to the upper part of the Subbotina trivialis Subzone (Parasubbotina pseudobulloides Zone) of Arenillas et al. (2004). It is not abundant, and is easily confused with Woodringina claytonensis (Fig. 1).

References:

Arenillas, I., Arz, J. A. & Gilabert, V. (2017). Revalidation of the genus Chiloguembelitria Hofker: Implications for the evolution of early Danian planktonic foraminifera. Journal of African Earth Sciences. 134: 435-456. gs

CATALOG OF ORIGINAL DESCRIPTIONS: Chiloguembelitria biseriata Arenillas et al. 2017

Chiloguembelitria biseriata

References:

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