Nannotax3 - ntax_Farinacci

Original descriptions of taxa - also emended descriptions for a few taxa. For coccolithophores, and many calcispheres, these are pages from the Farinacci & Howe Catalog of Calcareous Nannofossils. In other cases (e.g. non-calcifying haptophytes) the data is directly compiled on this site. The "Catalogue of Calcareous Nannofossils" was originally compiled by Prof A. Farinacci 1969-1989, since 2000 it has been updated and extended by Richard Howe - see The Farinacci and Howe Catalog - an Introduction.
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Type species: Senelia plevrotos Varol 2023

Type repository: not stated, presumalby the author's collection

Diagnosis: A circular coccolith comprising a non-birefringent distal shield, a broad tube cycle without distal protrusion, and an appressed proximal shield.

Description: The number of segments constructing the distal shield is between 26 and 40. The tube cycle and proximal shield combination create an asymmetrical X-shape structure in side view (Plate16, Figs. 3,7; Plate 17, Figs. 2,6). The broad tube cycle is flush with the distal shield. The narrowest point of the central area lies at the boundary between the tube cycle and its proximal shield that corresponds to the sharp tapering inner end of the distal shield.

Senelia includes two new species, Senelia plevrotos and Senelia perifanos.

Senelia plevrotos and Senelia perifanos differ by the shape of their tube cycle and the distal shield in their side view. The distal shield has pointed ends in Senelia perifanos and rounded ends in Senelia plevrotos.

The width of the x-shape structure is much greater than its height in Senelia perifanos. The smooth tube cycle’s diameter is often two times wider than the width of the shield in Senelia perifanos; this can be seen in both the side view (Plate 16, Fig. 3,7) and plan view (Plate 16, Fig. 14).

In Senelia plevrotos, the periphery of the tube cycle is serrated, and its diameter is about equal to the width of the shield.

Optical properties: In cross-polarised light, identifying the curved direction of the inclined extinction lines (symmetrical) is challenging.

Seneliadisplays laevogyre extinction lines distally (Plate 17, Figs. 10,14) and dextrogyre extinction lines proximally (Plate 17, Figs. 11,15). With the gypsum plate inserted, the blue sectors correspond to the horizontal axis on the distal side (Plate17, Fig. 14). In contrast, the blue sectors correspond to the vertical axis on the proximal side (Plate17, Fig. 15).

In honour of late geologist Dr. Mustafa S ¸ enel, Ankara, Turkey. Mustafa’s geological and stratigraphical work on the Taurus Mountains enormously contributed to compiling and publishing Turkey’s 1/100,000, 1/250,000 and 1/500,000 scaled geological maps at the MTA Geological Studies Department.

Remarks: Senelia differs from Noelia and Mauriceblackia by lacking a distally protruding tube cycle above the distal shield. Senelia is distinguished from Davidbukrya and Carlamuelleria by having an appressed proximal shield. Davidbukrya has no proximal shiel, and Carlamuelleria has a vestigial diminutive proximal shield.

The spaced proximal shield is present in Coccolithus formosus (Plate 2, Figs.2, 6), Markalius astroporus (Plate 1, Figs. 15,19) and Mauriceblackia media (Plate 2, Figs. 14,18). In Senelia, the appressed proximal shield is contracted and bound to the inner perimeter of the distal shield.

References:

Varol, O. (2023). New Paleocene calcareous nannofossils: Carlamuelleria, Davidbukrya, Mauriceblackia, Noelia and Senelia. Marine Micropaleontology. 180: 1-41. gs

CATALOG - Senelia

References:

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				Senelia perifanos Varol 2023 = Senelia perifanos
				Senelia plevrotos Varol 2023 = Senelia plevrotos