Xiphodolamia maliki, Artüz & Sakinç, 2025

Artüz, M. Levent & Sakinç, Mehmet, 2025, Description of a new species, Xiphodolamia maliki sp. nov. and the shark teeth of Middle Eocene (Lutetian) aged Soğucak Formation in Küçükçekmece, Istanbul, Turkey, Zootaxa 5646 (4), pp. 527-544 : 536-537

Xiphodolamia maliki sp. nov.

LSID: urn:lsid:zoobank.org:pub:D1138F87-2F78-430C-9DBD-E9A83B19B639

Fig. 7

Material: Forty-four mostly poorly preserved teeth in the Malik Sayar Collection

Material examined: Holotype: After measurements were taken and it was photographed in its entirety before preparation, it was prepared as a section slide and recorded with the QR code number LA60-001.00 ( Fig. 7 a–d ) and added to the Malik Sayar Collection. Paratypes: 23 anterior teeth, 2 intermediate teeth, 14 lateral teeth, and 5 symphysial teeth were bulk-stored in the Malik Sayar Collection with their original labels and re-QR coded under the number AK14-009.00.

Locality: On the eastern shore of the Küçükçekmece Lagoon ( Fig. 4 ; 5 ) in the Eocene Epoch, Lutetian-aged level, Soğucak Formation ( Fig. 6 ).

Description based on holotype teeth:

The teeth are laterally compressed, exhibiting a narrow, triangular, dagger-shaped crown with sharp edges along both borders. The crown typically presents a slightly sigmoid curvature along the mesial cutting edge, while the posterior edge is obtuse. The construction of the root reveals a strong labio-lingual flattening, where both sides appear compressed, causing the processes to run parallel and obliquely; occasionally, one process is shorter than the other.

The crown is smooth, without basal cusps, serrations, or folds on the labial or lingual surfaces of the dentin. The broad crown extends fully to the root, which is quadrangular and lacking lateral denticles. A faint lingual groove is present on the root, containing a small nutrient foramen at its summit. The lingual crown face is convex, featuring a distinct uvula flanked by deep depressions on both sides. In labial view, the crown face is flat, while the mesial cutting edge is straight in profile. The distal cutting edge transitions at an acute angle into a distal heel, separated by a notch.

Some teeth display signs of poor preservation, particularly in the root region, which may be attributed to fossilisation processes or post-collection storage conditions.

Figures

FIGURE 4. Locality map showing the point (marked with a black dot) where the shark tooth fossils were collected. The Küçükçekmece Basin is located southeast of Küçükçekmece Lake (Lagoon) and is one of the major Tertiary sedimentary basins in Thrace, Turkey.

FIGURE 5. Generalized geological map of the location where the teeth were found, adapted from Arıç (Sayar), (1955)

FIGURE 6. Generalized stratigraphic columnar section of the Küçükçekmece Basin (explained in text).

FIGURE 7. Xiphodolamia maliki sp. nov. (a–d) Holotype: LA60-001.00, anterior tooth. a) labial view; b) mesial view; c) distal view; d) lingual view. (e–f) selected mandibular lateral teeth; e) labial view; f) lingual view. (g–h) selected maxillar lateral tooth; g) labial view; h) lingual view. (j–m) selected maxillar intermediate tooth; j) lingual view; k) labial view; l) mesial view; m) distal view. (Scale bar 10 mm)