Glaucostegus

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.^[1] They were formerly classified in the family Rhinobatidae but are now recognized as a distinct family, Glaucostegidae.^[2]

Glaucostegus
Giant guitarfish (G. typus)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Chondrichthyes
Subclass:	Elasmobranchii
Order:	Rhinopristiformes
Family:	Glaucostegidae Last, Séret & Naylor, 2016
Genus:	Glaucostegus Bonaparte, 1846

Their upperparts are uniform pale yellowish, brownish or greyish, and the nose is pale. Most are large, reaching 1.7–3 m (5.6–9.8 ft) in length depending on the exact species involved, except for the small G. obtusus that is less than 1 m (3.3 ft).^[1]

Species

There are ten recognized species, all of which are classified as critically endangered:^[2][3]

• Glaucostegus cemiculus (Geoffroy St. Hilaire, 1817) (Blackchin guitarfish)
• Glaucostegus granulatus (Cuvier, 1829) (Sharpnose guitarfish)
• Glaucostegus halavi (Fabricius 1775) (Halavi guitarfish)
• Glaucostegus microphthalmus (H.-T.Teng, 1959) (Smalleyed guitarfish)
• Glaucostegus obtusus (Müller & Henle, 1841) (Widenose guitarfish)
• Glaucostegus petiti (Chabanaud, 1929) (Madagascar 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)