<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Dasyatis Rafinesque 1810</title> <meta content="text/html; charset=UTF-8" http-equiv="content-type"/> </head> <body> <h1>Genus <i>Dasyatis</i> Rafinesque, 1810</h1> <p> <i>Dasyatis</i> Rafinesque, 1810:16. Type species <i>Dasyatis ujo</i> Rafinesque, 1810 (= <i>Raja pastinaca</i> Linnaeus, 1758); designated by monotypy.</p> <p> <b>Definition</b>. Small to medium-sized dasyatids (adults to 38–84 cm DW) characterised by the following: robust, rhombic disc with pectoral-fin apex narrowly rounded to angular; snout broadly angular and short (1.1–1.5 times combined orbit and spiracle length); eye medium-sized to large and protruding slightly; nasal curtain broadly skirtshaped; mouth medium-sized, with 3–7 oral papillae (3 centrally); tail firm, somewhat filamentous distally (length 1.2–2.3 times DW), its base broad to very broad and depressed; pelvic fins medium-sized to large, protruding well beyond disc; dorsal fold variably developed, low or reduced to form a ridge; ventral fold low (better developed in <i>D. pastinaca</i>) with a short to long base; caudal sting typically forward on tail (distance from pectoral-fin insertion to caudal-sting base 1.8–3 times interspiracular width); no median thorns on disc and denticle band absent; skin typically smooth, except in largest adults which may have sparse coverage of denticles and sometimes welldeveloped thorns on anterior tail; scapular thorns absent; tail smooth or prickly; dorsal coloration plain or with prominent pattern; ventral surface white, disc margin sometimes dark; tail plain, black distally; marine, Atlantic and South-West Indian Ocean.</p> <p> <b>Species</b>. <i>D. chrysonota</i> (Smith, 1828), <i>D. hypostigma</i> Santos & Carvalho, 2004, <i>D. marmorata</i> (Steindachner, 1892), <i>D. pastinaca</i> (Linnaeus, 1758), and <i>D. tortonesei</i> Capapé, 1977.</p> <p> <b>Remarks</b>. The polyphyletic genus <i>Dasyatis</i>, once thought to consist of 36 species with widespread distributions in tropical and temperate seas, now applies to a monophyletic group of five small to medium-sized species found in the Atlantic (including the Mediterranean Sea) and SW Indian Ocean (see Fig. 1). Molecular data supports the non-conspecificity of similar blue-marbled forms, <i>D. chrysonota</i> and <i>D. marmorata</i>.</p> </body> </html>