Updated keys to the genera in the subfamilies of Cyclocoelidae Stossich, 1902, including a reconsideration of species assignments, species keys and the proposal of a new genus in Szidatitreminae Dronen, 2007

Abstract

Keys to the six subfamilies, 22 genera within subfamilies and 128 species recognized within the Cyclocoelidae are provided. Lists of species in each genus are provided, along with taxonomic summaries that include type host, type locality, additional hosts, additional localities, previously proposed synonyms, and remarks for each species. The following synonymies are proposed: Cyclocoelum mutabile (Zeder, 1800)-Syn. C. microstomum (Creplin, 1929); Cyclocoelum leidyi Harrah, 1922-Syn. C. cuneatum Harrah, 1922; Cyclocoelum mehrotrai Sinha & Sahay, 1975-Syn. C. mathuri Jain, 1984; Selfcoelum allahabadi (Khan, 1935) n. comb.-Syns. Cyclocoelum agamprasadi Jain, 1983, Cyclocoelum erythropis Khan, 1935 and Cyclocoelum indicum Khan, 1935; Selfcoelum obliquum (Harrah, 1921) n. comb.-Syn. Cyclocoelum mehrii Khan, 1935; Uvitellina adelphus (Johnston, 1917)-Syn. Cyclocoelum (Uvitellina) dollfusi Tseng, 1930; Uvitellina kaniharensis (Gupta, 1958)-Syn. U. indica Siddiqi & Jairajpuri, 1962; Uvitellina simile (Stossich, 1902) n. comb.-Syn. U. magniembria Witenberg, 1923; Uvitellina vanelli (Rudolphi, 1819)-Syns. U. keri Yamaguti, 1933 and U. tageri Yamaguti, 1933; Wardianum triangulare (Harrah, 1922)-Syn. Wardianum catoptrophori Dronen, 2007; Haematotrephus limnodromi Dronen, Gardner & Jiménez, 2006-Syn. H. selfi Dronen, Gardner & Jiménez, 2008; and Hyptiasmus arcuatus (Brandes, 1892 of Stossich, 1902)-Syn. H. coelonodus Witenberg, 1923. Based on the lack of adequate descriptive information, Cyclocoelum cornu (Zeder, 1800); Cyclocoelum crenulatum (Rudolphi, 1809); Haematotrephus nigropunctatum (von Linstow, 1883) n. comb.; Haematotrephus robustus Ukoli, 1968; Hyptiasmus californicus (Wootton, 1966); and Hyptiasmus vigisi Savinov, 1960 are considered to be species inquirendae. Hyptiasmus witenbergi Tret'iakova, 1940 (described in a dissertation) is considered to be a nomen nudum. Comparative tables containing measurements, morphometric percentages and morphometric ratios for species in the family are provided and the comparative characteristics used to distinguish species in the Cyclocoelidae are discussed.

Intraspecific variation in adult Uvitellina iraquensis Dronen, Ali & Al-Amura, 2013 (Cyclocoelidae: Haematotrephinae) from two collection sites of white-tailed lapwing, Vanellus leucurus (Lichtenstein) (Charadriiformes: Charadriidae), in Iraq

“…Based on this study we feel the length of the cirrus sac can be a valuable characteristic for separating species and groups of species in cyclocoelids, especially when the percentage of its length relative to the length of the body also is considered. Generally, we agree with Dronen & Blend (2015) that where consistent differences are apparent in the posterior extent of the cirrus sac relative to the intestinal bifurcation and/or the length of the cirrus sac relative to body length that these characteristics can be valuable tools in distinguishing species of cyclocoelids. It should be kept in mind when comparing specimens where the anterior aspect of the ceca has become swollen, that the increased width of the ceca may alter the perception of the extent that the cirrus sac overlaps the ceca at the level of the intestinal bifurcation.…”

“…Previous authors (e.g. Szidat 1932;Stunkard 1966;Macko et al 2011;Dronen 2002;Dronen & Blend 2015) have noted variability in position and size of the gonads in cyclocoelids. Whereas we consider the placement of the ovary relative to the position of the testes and the location of the gonads in the body relatively strong characteristics to diagnose subfamilies and sometimes genera in this family (e.g.…”

“…In our opinion the presence or absence of suckers represent a relatively good distinguishing characteristic. Dronen & Blend (2015) noted that in general the presence of the oral sucker is more easily determined than that of the ventral sucker in cyclocoelids, and that histological sectioning often may be required to detect the presence of the ventral sucker. These authors also pointed out that when a rudimentary oral sucker is present in cyclocoelids, its outer boundary may be vague and difficult to see, and some specimens also may require histological sectioning to access the width and length accurately, often precluding the use of the oral sucker/ pharynx width ratio.…”

“…Dronen & Blend (2015) indicated that the anterior end of species of cyclocolids have a tendency to contract even when specimens are heat-fixed using an accepted method. The length of the prepharynx was quite variable in our specimens; however, generally the length of the prepharynx beyond being presence or absent, or longer or shorter that the esophagus, is known to be quite variable in many groups of flukes and investigators should be cautious of using measurements of the prepharynx length in separating species and/or genera in the Cyclocoelidae Stossich, 1902.…”

“…Many previous authors have considered the testes size to be one of the most variable characteristics in flukes (e.g. Szidat 1932;Stunkard 1966;Macko et al 2011;Dronen 2002;Dronen & Blend 2015). Dronen (2007) and Dronen & Blend (2015) considered the size, shape and appearance of the testes to be too variable in most cyclocoelids to be effective as a distinguishing characteristic at the species or genus levels.…”