Clinostomum poteae n. sp. (Digenea: Clinostomidae), in the trachea of a double-crested cormorant Phalacrocorax auritus Lesson, 1831 and molecular data linking the life-cycle stages of Clinostomum album Rosser, Alberson, Woodyard, Cunningham, Pote & Griffin, 2017 in Mississippi, USA

Abstract

Clinostomum spp. (Digenea: Clinostomidae) are a group of trematodes commonly found in the buccal cavity and oesophagus of a variety of piscivorous birds. The metacercariae, colloquially known as "yellow grubs," have been reported from a diverse group of freshwater fishes worldwide. In the catfish farming region of the southeastern USA, piscivorous birds present a continuous challenge for aquaculturists in the form of fish depredation and the introduction of trematodes into these static, earthen pond systems. Clinostomum spp. are commonly encountered in farm-raised catfish. While generally considered pests of minimal importance, heavy infections can result in unmarketable fillets. Of the piscivorous birds that frequent catfish aquaculture operations in the southeastern US, the double-crested cormorant (Phalacrocorax auritus Lesson) is one of the most damaging, although reports of Clinostomum spp. from P. auritus are limited. In this study, adult trematodes morphologically consistent with Clinostomum sp. were found in the trachea of a double-crested cormorant captured in Lowndes Co., Mississippi, USA. These specimens differed from other recognised Clinostomum spp. in several key morphological characters. Moreover, sequence data of mitochondrial cytochrome c oxidase subunit 1 gene (cox1), nicotinamide adenine dinucleotide dehydrogenase subunit 1 gene (nad1) and ribosomal internal transcribed spacer (ITS) regions did not match any known Clinostomum sp. for which sequence data are available. While genetically similar to C. marginatum and C. album Rosser, Alberson, Woodyard, Cunningham, Pote & Griffin, 2017 reported from the great egret Ardea alba L. in Mississippi, these adult clinostomids were larger in size and limited to the trachea, whereas both C. marginatum Rudolphi, 1819 and C. album are found in the oral cavity and esophagus. Given these distinct morphological and molecular characters we propose a new member of the genus, known hereafter as Clinostomum poteae n. sp. Additionally, larval stages in the life-cycle of C. album are morphologically and molecularly identified for the first time from ramshorn snails Planorbella trivolvis Say and fathead minnows Pimephales promelas Rafinesque.

The Digenean <i>Clinostomum complanatum</i> Found from Great Cormorant <i>Phalacrocorax carbo</i> in Japan

“…Twelve out of the 20 species have been validated using a combined morphological and molecular approach. Besides, several putative species recognized solely through DNA sequences are proposed (Rosser et al, 2018;Sereno-Uribe et al, 2018). Among these species, the present worm is morphologically identified as C. complanatum.…”

“…The taxonomy of the genus Clinostomum had been complicated. According to recent studies, the genus currently contains 20 described species (Briosio-Aguilar et al, 2018;Rosser et al, 2018;Sereno-Uribe et al, 2018). Twelve out of the 20 species have been validated using a combined morphological and molecular approach.…”

Patterns ofClinostomum marginatuminfection in fishes and amphibians: integration of field, genetic, and experimental approaches

“…Although trematodes in the genus Clinostomum are broadly distributed geographically and have been studied extensively, the taxonomy of this group has been the subject of extensive debate and discussion. Thus far, there are 31 recognized species of Clinostomum recorded from all continents other than Antarctica (see supplementary tables 1–3), of which 20 include some degree of support using genetic techniques (Locke et al , 2015; Caffara et al , 2017; Briosio-Aguilar et al ., 2018; Rosser et al ., 2018; Sereno-Uribe et al ., 2018). For the 14 species reported in North America (see supplementary table 3), differentiation among species is often believed to differ based on their use of second intermediate hosts, with nine species infecting only fishes, one infecting only amphibians, and two using both host groups.…”

“…marginatum in both fishes ( Micropterus salmonoides ) and salamanders ( Eurycea tynerensis and E. spelaea ) in Oklahoma. While DNA sequence analyses have helped to validate the taxonomic identity, differentiated between species, and uniqueness of several previously identified species of Clinostomum , both in the New and Old World (Caffara et al , 2011; Sereno-Uribe et al , 2013, 2018; Locke et al , 2015; Pinto et al , 2015; Pérez Ponce de León et al , 2016; Rosser et al ., 2018), the extent of their specificity to a second intermediate host remains conjectural.…”

Two New Metacercariae of Genus Austrodiplostomum (Trematoda: Diplostomidae) from Oreochromis niloticus (Cichlidae) and Varicorhinus beso (Cyprinidae) in Tana Lake, Ethiopia

“…Before this study, the genus Austrodiplostomum was represented by three species: A. compactum , A. mordax Szidat et Nani, 1951(Szidat & Nani, 1951, and A. ostrowskiae Dronen, 2009(Dronen, 2009). All of them as adult are endohelminthic parasites of cormorants Szidat & Nani, 1951;Ostrowski de Núñez, 1970;Dubois & Macko, 1972;Nasir & Díaz, 1972;Dubois, 1977;Rietschel & Werding, 1978;Fedynich et al, 1997;Dronen, 2009) and freshwater fishes (Machado et al, 2005;Salgado-Maldonado, 2006;Novaes et al, 2006;Violante-González et al, 2009) (Rosser et al, 2016). As metacercariae the genus Austrodiplostomum was represented by A. compactum Dubois, 1970, A. mordax (Szidat et Nani, 1951) n.…”