Glaucostegus, also known as giant guitarfishes, is a genus of large Indo-Pacific rays, with a single species, Glaucostegus cemiculus, in the East Atlantic, and Mediterranean. They were formerly classified in the family Rhinobatidae but are now recognized as a distinct family, Glaucostegidae.
Their upperparts are uniform pale yellowish, brownish or greyish, and the nose is pale. Most are large, reaching in length depending on the exact species involved, except for the small G. obtusus that is less than .
Species There are nine recognized species, all of which are classified as critically endangered:
Glaucostegus cemiculus (Geoffroy St. Hilaire, 1817) (Blackchin guitarfish) Glaucostegus granulatus (Cuvier, 1829) (Sharpnose guitarfish) Glaucostegus halavi (Fabricius 1775) (Halavi guitarfish) Glaucostegus microphthalmus (Teng, 1959) (Smalleyed guitarfish) Glaucostegus obtusus (Müller & Henle, 1841) (Widenose guitarfish) Glaucostegus spinosus (Günther, 1870) (Spiny guitarfish) Glaucostegus thouin (Anonymous [Lacépède], 1798) (Clubnose guitarfish/Thouin ray) Glaucostegus typus (Anonymous [E. T. Bennett], 1830) (Giant guitarfish) Glaucostegus younholeei (Habib & Islam, 2021) (Bangladeshi guitarfish)
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