Carcharhinus cf. sorrah (Valenciennes, 1839)

Jirapatrasilp, Parin, Cuny, Gilles, Kocsis, László, Sutcharit, Chirasak, Ngamnisai, Nom, Charoentitirat, Thasinee, Kumpitak, Satapat & Suraprasit, Kantapon, 2024, Mid-Holocene marine faunas from the Bangkok Clay deposits in Nakhon Nayok, the Central Plain of Thailand, ZooKeys 1202, pp. 1-110 : 1-110

Carcharhinus cf. sorrah (Valenciennes, 1839)

Fig. 20

cf. Carcharias (Prionodon) sorrah Valenciennes in Müller & Henle, 1839: 45 – 46, pl. 16. Type locality: Java.

cf. Carcharhinus sorrah . Compagno 1984: 500 – 501, with in-text figs. Krajangdara et al. 2022: 57, with in-text figs.

Referred material.

CUF - NKNY - 3.1 (Fig. 20 A – G ), CUF - NKNY - 3.2 (Fig. 20 H – N ) (2 upper teeth).

Description.

The crown is compressed labio-lingually. The labial face is slightly flatter than the lingual one. The cusp is inclined distally and presents a notch on its distal part. The serrations do not reach the apex of the main cusp and are enlarged, becoming more complex basally, especially on the distal heel. The mesial edge of the crown is almost straight in labial or lingual view. The base of the root is slightly concave in lingual or labial view. There is a well-developed groove with a nutritive foramen at the base of the root in lingual view.

Habitat.

Coastal, shallow-water zones of the continental and insular shelves, primarily around coral reefs at intertidal zones down to 73 m depth ( Compagno 1984; Krajangdara et al. 2022).

Distribution.

Red Sea and Indian Ocean; Indo-West Pacific, from China to Australia ( Compagno 1984).

Record in Thailand.

Gulf of Thailand and Andaman Sea ( Compagno 1984; Krajangdara et al. 2022).

Taxonomic remarks and comparisons.

Some upper teeth of C. sorrah appear to display a mesial cutting edge slightly more convex than on our specimens, but this character is known to depend on ontogenetic stages and the position of the teeth in the jaw (e. g., Bass et al. 1973: pl. 13; Garrick 1982: fig. 76). Juveniles of C. dussumieri may have upper teeth with similar characteristics, but the distal cutting edge of the main cusp is not serrated. This latter character appears in larger specimens, but the mesial cutting edge of the main cusp becomes slightly concave. In addition, the distal heels and the distal root lobe of the fossil teeth are more elongated than the upper teeth of C. dussumieri ( White 2012) .

Figures

Figure 20. Carcharhinid shark teeth - Carcharhinus cf. sorrah A – G specimen CUF - NKNY - 3.1 A lingual B apical C labial D mesial and E distal views F, G close-ups of the serration F on the distal heel and G on the middle part of the cusp mesial cutting-edge H – N specimen CUF - NKNY - 3.2 H lingual I apical J labial K mesial and L distal views M close-up of the serration on the lower part of the mesial cutting-edge and N close-up of the serration between the heel and the base of the distal cutting edge.