Macroramphosus gracilis (Lowe, 1839)

Murat Bilecenoglu, 2006, Status of the genus Macroramphosus (Syngnathiformes: Centriscidae) in the eastern Mediterranean Sea., Zootaxa 1273, pp. 55-64 : 58-60

Macroramphosus gracilis (Lowe, 1839)

(Figure 2B)

Material examined: ESFM-PIS/9805, 9 specimens, 43-67 mm SL, northern Cyprus (35º13’N - 33º56’E), 102 m, 14 July 1998 ; ESFM-PIS/0202, 3 specimens, 56-66 mm SL, Babakale-Çanakkale (northern Aegean Sea), 140 m, 27 April 2002 ; ESFM-PIS/0211, 3 specimens, 56-84 mm SL, Kusadasi Bay (southern Aegean Sea), 160 m, 02 October 2002 ; ESFM-PIS/0416, 1 specimen, 106 mm SL, northern Aegean Sea, 70 m, 28 July 2004 .

Description: First dorsal fin IV -V, second dorsal finrays 11-13, anal finrays 18-19, pectoral finrays 16, caudal finrays 20-22. Body compressed and slender (maximum body depth 4.53 to 5.39 times in SL). Body height gradually decreasing after the first dorsal fin, forming no or slightly elevated hump over second dorsal fin base. Head elongate with long and tubular snout. Mouth opening very small, toothless, and located at tip of snout. Eye large, its diameter smaller than postocular head length, located close to dorsum of head, bearing a prominent supraorbital crest; a crest-like structure on the anterior part of the orbital region, having no spinules (Figure 3B). First dorsal fin clearly originating before anus; second spine strong, enlarged with serrated posterior edge (total number of denticules 0-14, mean=8.63), not extending beyond second dorsal fin base. Body covered with small and finely toothed scales. Bony plate structure on the body is similar to M. scolopax , with posterior edge of each plate serrated in adults. Ventral body profile almost straight; ventral scutes not protruding; projecting scute between pelvic and anal fins absent or poorly developed (Figure 4B). Fresh specimens of juveniles are dark brown and adults are brownish on the back, paler and silvery on the sides. Morphometric values are given in Table 1.

Distribution and biology: M. gracilis is a cosmopolitan species, distributed widely in the Indian, Pacific, and Atlantic Oceans (Ehrich & John, 1973; Wheeler, 1973). Occurrence of the species in various parts of the Mediterranean Sea was reported by several authors ( Günther, 1889; D’Ancona, 1933; Ben-Tuvia, 1962, 1971; Demetropoulos & Neocleous, 1969; Tortonese, 1970; Wheeler, 1973; Berdar et al., 1977; Bauchot & Pras, 1980). A single report of M. gracilis from Turkey was evaluated as doubtful (for full account, see Bilecenoglu et al., 2002).

Results of previous studies indicated that the species mainly occurs at depths between 100 and 450 m (Ehrich, 1976; Papaconstantinou & Tsimenides, 1979; Assis, 1993). Its growth pattern is similar to its congeneric species, with a short life span (five years) and a rapid attainment of maximum size (Borges, 2000). The feeding strategy of M. gracilis is selective both in the Atlantic and the Pacific oceans; individuals prey heavily on planktonic crustaceans (ostracods and copepods), quite different from the benthic diet of M. scolopax (Brethes, 1979; Matthiessen et al., 2003; Miyazaki et al., 2004).