A new species of Microtetrameres (Nematoda, Tetrameridae) parasitizing Buteogallus urubitinga (Aves, Accipitridae) from northeastern Argentina

Abstract A new tetramerid nematode, Microtetrameres urubitinga n. sp., is described from specimens recovered from the proventriculus of the great black-hawk, Buteogallus urubitinga (Aves: Accipitridae), from Formosa Province, Argentina. The males of the new species are characterized by having spicules unequal (length ratio of spicules 1:3.8–5.9) and dissimilar in shape (right spicule with a simple tip, left spicule with a symmetrical bifurcated tip), caudal papillae arranged asymmetrically (two pairs precloacal and two pairs postcloacal) and cloacal lips highly protruded forming a tube. The gravid females are permanently coiled clockwise or counterclockwise in a spiral and having a tail tapering gradually to a sharp point, with a cuticular fold. This is the first nominal species of Microtetrameres (Travassos, 1915) described parasitizing birds from Argentina. The relationship between the diet of B. urubitinga and the low prevalence of M. urubitinga n. sp. is discussed.摘要：本研究记述了采自阿根廷福尔摩沙省大黑鹰（Buteogallus urubitinga，鸟纲：鹰科）腺胃中的一新种微四棱线虫——乌宾提加微四棱线虫（Microtetrameres urubitinga n. sp.）。该新种雄虫的鉴别特征如下：交合刺不等长，长度比为1:3.8~5.9，且形态迥异——右交合刺顶端结构简单，左交合刺顶端呈对称二叉状；尾乳突呈不对称排列，包含2对肛前乳突与2对肛后乳突；泄殖腔唇高度突出，形成管状结构。怀卵雌虫呈永久性螺旋卷曲，可顺时针或逆时针缠绕，尾部逐渐变细至尖锐末端，且带有角质褶。本研究为阿根廷地区首次记述寄生于鸟类的微四棱线虫属（Microtetrameres, Travassos, 1915）有效物种。本文还探讨了大黑鹰的食性与乌宾提加微四棱线虫新种较低感染率之间的关联。