First record of the genus Syncuaria (Nematoda : Acuariidae) in Argentina, with description of a new species

The nematode genus Syncuaria Gilbert, 1927 (Acuariidae) is reported for the first time from Argentina with two ;species parasitic in Threskiornithidae . Syncuaria plegadisi sp. n. from the white-faced ibis, Plegadis chihi (Vie illot), is described and figured. The new species differs from known specie s of Syncuaria by the following characters: absence of lateral alae; cephal ic cordons narrow, consisting of cuticular plates dorsally and ventrally in vaginated forming a groove; presence of cephalic spines; spicules with simp le, rounded distal ends; left spicule two to three times longer than right one; female tail dorsally bent and distance between vulva and anus comparab le to tail length. Syncuaria diacantha Fetter, 1961, a common parasite of t he roseate spoonbill, Platalea ajaja L., is reported for the first time fro m Argentina and briefly described. SEM micrographs for both species are pro vided. Both S. plegadisi sp. n. and S. diacantha were found to co-occur in the same locality, but not on the same host, suggesting a high degree of ho st specificity.