Ariid swimbladders
Posted: 30 Aug 2010, 10:06
Marceniuk, AP & JLO Birindelli, 2010. Morphology of the gas bladder in sea catfishes (Siluriformes: Ariidae). Zootaxa 2579: 59–68.
Abstract
The morphology of the gas bladder and associated structures in sea catfishes (Siluriformes: Ariidae) is studied. The most simple gas bladder, exclusive to Galeichthys Valenciennes, is apple-shaped with weakly developed internal trabeculae, has smooth walls externally and a short Müllerian window associated with a broad, short Müllerian ramus that is firmly attached to Baudelot’s ligament and supracleithrum. Most genera of Ariidae have a cordiform bladder with well-developed trabeculae, smooth walls externally, an elongate Müllerian window and an elongate Müllerian ramus with an acute tip that is free from the Baudelot’s ligament and supracleithrum. Sciades proops (Valenciennes) and S. parkeri (Traill) have a similar gas bladder but with a well-developed secondary chamber. Other genera of Ariidae also have a cordiform bladder with well-developed trabeculae and elongate Müllerian window, but with lateral diverticula present as shallow rounded bulges or blister-like swellings along the peripheral margins of the bladder. The degree of development of lateral diverticula varies among and within species, with Osteogeneiosus Bleeker having the most highly-developed diverticula. Bagre pinnimaculatus (Steindachner) and Bagre bagre (Linnaeus) have unusual depressed gas bladders with complex network of internal trabeculae. The implications of gas bladder morphology for the taxonomy and phylogenetic relationships of the family are discussed.
Abstract
The morphology of the gas bladder and associated structures in sea catfishes (Siluriformes: Ariidae) is studied. The most simple gas bladder, exclusive to Galeichthys Valenciennes, is apple-shaped with weakly developed internal trabeculae, has smooth walls externally and a short Müllerian window associated with a broad, short Müllerian ramus that is firmly attached to Baudelot’s ligament and supracleithrum. Most genera of Ariidae have a cordiform bladder with well-developed trabeculae, smooth walls externally, an elongate Müllerian window and an elongate Müllerian ramus with an acute tip that is free from the Baudelot’s ligament and supracleithrum. Sciades proops (Valenciennes) and S. parkeri (Traill) have a similar gas bladder but with a well-developed secondary chamber. Other genera of Ariidae also have a cordiform bladder with well-developed trabeculae and elongate Müllerian window, but with lateral diverticula present as shallow rounded bulges or blister-like swellings along the peripheral margins of the bladder. The degree of development of lateral diverticula varies among and within species, with Osteogeneiosus Bleeker having the most highly-developed diverticula. Bagre pinnimaculatus (Steindachner) and Bagre bagre (Linnaeus) have unusual depressed gas bladders with complex network of internal trabeculae. The implications of gas bladder morphology for the taxonomy and phylogenetic relationships of the family are discussed.