Helminth parasites of Galápagos mammals: a new cestode of the genus <i>Raillietina</i> from the endemic rice rat <i>Nesoryzomys swarthi</i> and a summary of parasites from both endemic and invasive rodents

In this first report of endoparasites from endemic land-mammals of the Galápagos Islands, we describe a new species of cestode of the genus <i>Raillietina</i> (Cyclophyllidea: Davaineidae) from a species of <i>Nesoryzomys</i> and summarize the extent of helminth parasitism in both oryzomyine endemics and introduced species of <i>Rattus</i>. Up to the current time, no helminth parasites have been reported from rodents of the Galápagos, and little work has yet been done describing and synthesizing Galápagos parasite diversity. In historical times, several species of autochthonous rodents have occupied the islands including: <i>Nesoryzomys narboroughi</i> Heller 1904, <i>N. fernandinae</i> Hutterer and Hirsch 1979, <i>N. swarthi</i> Orr, 1938, and <i>Aegialomys galapagoensis</i> (Waterhouse, 1839). Colonization of the islands by humans brought 3 known species of synanthropic rodents: <i>Rattus rattus, R. norvegicus</i>, and <i>Mus musculus</i> which are suspected to have caused the extinction of at least 3 other oryzomyines in historical times.