Chlorurus sordidus (Forsskål, 1775)

Zajonz, Uwe, Bogorodsky, Sergey V., Saeed, Fouad K. N., Aideed, Moteah S. & Lavergne, Edouard, 2023, Parrotfishes (Teleostei: Labridae: Scarini) of the Socotra Archipelago: Diversity and distributional biogeography, including a range extension of Scarus zufar Randall & Hoover, 1995, Zootaxa 5389 (3), pp. 301-330 : 304-305

Chlorurus sordidus (Forsskål, 1775)

Scarus sordidus Forsskål in Niebuhr, 1775: 30; neotype: USNM 202297 ; type locality: Red Sea.

Bullethead Parrotfish

Figure 2

Material examined: Underwater photograph.

Distinctive characters: Body depth 2.3–2.5 in SL; front of head strongly rounded, the dorsal and ventral profiles about equally convex; teeth fully fused to form dental plates, mostly exposed, less than one-half covered by lips; cutting edge of dental plates distinctly denticulate; posterior nostril as large as anterior nostril; caudal fin truncate to slightly emarginate. Meristic values: Pectoral-fin rays 14; median predorsal scales 4, first largest; cheek with 2 scale rows, lower row with 5–8 scales.

Colouration: Initial phase dark reddish brown with two rows of whitish spots on side of body; caudal peduncle paler than body, usually with a faint blackish spot at caudal-fin base; dorsal fin dark reddish brown. Terminal males usually mainly green with lavender-pink scale edges, caudal peduncle distinctly lighter than body; head with green interorbital area and nape, two short green bands radiating from eye and green stripe or blotch below eye that bifurcating into two, edged ventrally with pink, stripes to upper lip and to chin; usually a diffuse yellowish area beneath dorsal half of pectoral fins.

Distribution: Red Sea along eastern Africa south to South Africa (KwaZulu-Natal), Madagascar and the Mascarene Islands, east to the Andaman Sea and western Indonesia. Known from the entire Arabian region from the Red Sea along Arabian Peninsula to the Arabian /Persian Gulf ( Randall & Bruce 1983; Randall 1995; Lips et al. 2016).

Remarks: The photographed terminal male matches the description of Chlorurus sordidus given by Randall & Bruce (1983) and Randall (1995), supporting the record of Zajonz et al. (2019). The species occurs at all islands of the Archipelago on seaward coral-dominated habitats at depths of 4–15 m, though it is rare. The photographed individual was observed at Samha Island in an area with soft corals at 10 m depth. Terminal males from the Red Sea and Gulf of Aden, in contrast to males from the Indian Ocean, possess a broad pink or pinkish orange zone across cheek and lack green bands radiating from the eye.

Figures

FIGURE 2. Chlorurus sordidus, terminal male, Samha Island, Socotra Archipelago, 10 m depth.