New host and locality records for Hispidorhynchus australiensis (Trypanorhyncha: Eutetrarhynchidae) from Aetobatus flagellum in the Persian Gulf

In order to evaluate the trypanorhynch cestodes of Aetobatus flagellum (Bloch & Schneider) from the Persian Gulf, the intestines of 15 longheaded eagle rays were examined off Hormozgan Province, resulted in identification of Hispidorhynchus australiensis (Toth, Campbell & Schmidt, 1992). Prevalence, intensity, abundance, and mean intensity were 20%, 3–15, 2 ± 4.8, and 10 ± 6.2, respectively. New host and locality records are established for H. australiensis. The new locality record expands the geographical distribution of this cestode species from Northern Territory, Australia to the northwestern Indian Ocean. In the Indian Ocean, where the geographic distributions of the type host, A. ocellatus (Kuhl), and A. flagellum overlap, host switching probably occurred by the common food sources of the two eagle ray species, namely by the invertebrates played a role in the life cycle of the parasite. The Iranian specimens were consistent morphologically with the description and redescription of H. australiensis, i.e., the type and voucher specimens of the Northern Territory, Australia. The Iranian specimens of the Persian Gulf were also consistent morphologically with the ten vouchers of H. australiensis from the Arafura Sea (AHC 29493–10), loaned from the South Australian Museum for comparison. Although the shape, size of the hooks, and the armature pattern of the Iranian specimens were similar to those of the Australian type material and vouchers, the size of the scolex and its internal organs were greater in the Iranian specimens. This issue is considered here as the intraspecific variations. The metric comparison of H. australiensis is presented for the specimens of the Persian Gulf and the Australian type material and vouchers in a table. Three Iranian vouchers were deposited in the Natural History Museum of Geneva, Switzerland (MHNG–PLAT–0157453).