2009年7月30日 星期四

巴西南部產變色龍鯛之一新種 - Australoheros taura

文獻來源: Ottoni FP, Cheffe MM. 2009. A new species of Australoheros from the upper rio das Antas, laguna dos Patos System, southern Brazil. Spixiana 32 (1): 153-159. [全文下載]

Abstract
A new species of Australoheros, with the longest snout of the genus, is herein described from small tributaries of the upper rio das Antas, rio Jacuí drainage, a region characterized by rivers with rapids. This new species differs from A. ribeirae and other undescribed species from southeastern Brazil by caudal and precaudal vertebrae counts, and differs from A. ribeirae by having a deeper body and a lower preorbital depth. It is also distinguished from all the southern species by having pink to red dominant males (except A. minuano) and a longer snout (except A. tembe and A. forquilha). Australoheros taura differs in color pattern characters from A. scitulus and A. forquilha by having no mark on side of head; from A. facetus and A. minuano by having a very narrow caudal-fin base spot; and from A. kaaygua by having a visible caudal-fin base spot. The new species is distinguished from A. forquilha, A. tembe, A. scitulus and charrua by having fewer caudal vertebrae; and from A. tembe by having fewer total vertebrae. Australoheros taura also differs from its congeners from southern Brazil by other meristic and morphometric characters, i.e., more anal-fin rays, longer caudal peduncle, fewer total vertebrae, and longer predorsal length. Based on three apomorphic characters (four scales of dorsal-fin origin series, 12–13 proximal radial and caudal-fin base spot very narrow), A. taura is closely related to A. kaaygua, A. charrua and A. scitulus group. Not being included in the group containing A. sp. jacui, although it is recorded from the same river basin.