Ascocotyle (Phagicola) rara sp. n. (Digenea, Heterophyidae) from Ixobrychus exilis (Aves, Ardeidae) in Brazil

Abstract

Ascocotyle (Phagicola) rara sp. n. is described from the intestine of Ixobiyclius exilis (Gmelin, 1789), a Brazilian bittern. The new species is compared with Ascocotyle (Phagicola) angeloi Travassos, 1928 and Ascocotyle (Phagicola) moUieiiisicola (Sogandares-Bernal & Bridgman, 1960); the main distinguishing characters are related to the aspect of the gonotyl that is not perforated in A. (P.) rara sp. n. when compared to A. (P.) mollienisicola and the absence of the crown of spines at the anteriorend in the new species compared withA. (P.) angeloi. This is an important finding, since human infections by Phagicola spp. have been previously reported in Brazil

Taxonomic status of Ascocotyle (Phagicola) rara Arruda, Muniz-Pereira et Pinto, 2002 (Digenea: Heterophyidae)

“…(P.) rara does the genital pore open dextral to the genital sac as described by Arruda et al (2002). In the present study, the terminal part of the uterus was observed to simply follow the antero-sinistral margin of the ventral sucker to open into the ventrogenital sac together with the ejaculatory duct and gonotyl (Fig.…”

“…(P.) rara are in fact smooth, lacking any tegumental spines that were reported and illustrated by Arruda et al (2002). Actually, the outer, syncytial layer of the tegument of A.…”

“…Re-examination of Ascocotyle (Phagicola) rara specimens has shown other morphological features than those in the original description by Arruda et al (2002) and slight differences in some of the measurements (Table 1).…”

“…24-32 (probably 28) spines in total, considering the alleged presence of two complete circles. Arruda et al (2002) presented the specimen illustrated in Fig. 1 as in total, ventral view, but in the slide itself, the specimen is folded at the mid-length, showing the anterior half part in the ventral view and the posterior part of the body in the dorsal view.…”

“…However, most of these specimens were grouped on permanent slides, altogether with the host's intestinal scrapings and, although the labels refer to their status as type or voucher specimens, they were not separately assigned on the slides deposited at the Helminthological Collection of Instituto Oswaldo Cruz (CHIOC). Arruda et al (2002), while studying Travassos' material of Ascocotyle from CHIOC, found two specimens on the slides Nos. 2632 and 2639 without circumoral spines, which they described as Ascocotyle (Phagicola) rara.…”