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Table 5 Comparative data for morphological characters among the selected cryptogonimid genera based on [44] and this study

From: Uncharted digenean diversity in Lake Tanganyika: cryptogonimids (Digenea: Cryptogonimidae) infecting endemic lates perches (Actinopterygii: Latidae)

 Neocladocystis Manter & Pritchard, 1969 (amended diagnosis)Tanganyikatrema n. g.Grandifundilamena novemtestes n. g., n. sp.Acanthostomum Looss, 1899Brientrema Dollfus, 1950Claribulla Overstreet, 1969Iheringtrema Travassos, 1947Isocoelium Ozaki, 1927Siphodera Linton, 1910
Body shapeIrregular ovalElongate, fusiformLong, relatively narrowElongate-oval to distinctly elongateFusiformElongate with distinct constriction immediately posterior to oral suckerElongate-ovalVery elongateOval, enlongate-oval
BL/BW1.5–2.54–7c.112–3.52–2.5c.6c.311–162–3.5
OSAlmost round, opens subterminallyInfindibular or cup-shaped, massive, relatively large, longer than wide, squared-off posteriorly, opens terminallyMassive, broadly infundibular, opens terminallyFunnel-shaped, opens terminallyNearly round, opens terminallyFunnel- or cup-shaped, opens almost terminallyAlmost round, opens subterminallyLonger than wide, opens subterminallyNearly round, opens almost terminally
Circumoral spinesAbsentAbsentAbsentEnlarged (rarely absent)EnlargedAbsentAbsentAbsentAbsent
VSPre-equatorial, rounded, unspecialised, not obviously embedded in ventrogenital sacPre-equatorial, rounded, unspecialised, embedded in ventrogenital sacPre-equatorial, rounded, much smaller than oral sucker.Pre-equatorial, rounded, unspecialised, not obviously embedded in ventrogenital sacPre-equatorial, rounded, unspecialised, embedded in ventrogenital sacPre-equatorial, rounded unspecialised, deeply embedded in ventrogenital sacPre-equatorial, rounded, unspecialised, not obviously embedded in ventrogenital sacPre-equatorial, rounded, unspecialised, not obviously embedded in ventrogenital sacPre-equatorial, rounded unspecialised, embedded in ventrogenital sac, usually smaller than VS
OSW/VSW1.5–2.10.8–1.7c.2.71–2.51.5–2.5c.2.52.0–2.5c.2.01–2.5
TegumentSmooth or spined, spines reach to posterior extremity, largest in mid-regionSpined, spines can reach at about level of ovarySpines not observedSmooth or spined, spines reach to posterior extremitySpined, spines reach to posterior extremitySpines not observedSpines not observedSpines not observedSpined
Forebody26–40% of BL30–62% of BLc.24 % of BL5–40% of BL20–25% of BLc.40% of BLc.20% of BL20–25% of BL20–33% of BL
PrepharynxShort or absentVariable in lengthBroadly oval, larger than ventral suckerShortVery shortVery shortVery shortShortShort
OesophagusShort or indistinctShorter than prepharynxAbsentShortVery shortShortVery shortLongShort
Intestinal bifurcationIn about mid-forebody, at level of ventral suckerIn posterior forebody just anterior to VSIn posterior forebodyImmediately anterior to VSImmediately anterior to or dorsal to VSIn anterior forebodyIn mid-forebodyIn posterior forebodyIn mid-forebody
CaecaBlind, end at level of testes or post-testicular regionBlind, reach into post-testicular regionBlind, reach into post-testicular regionOpens via separate ani close to posterior extremityBlind, end close to posterior extremityBlind, end posteriorly to testesBlind, end close to posterior extremityBlind, end close to posterior extremityBlind, end close to posterior extremity
Testes2, symmetrical or oblique, lobed, contiguous or slightly separated2, entire, tandem, contiguous, in posterior third of hindbody; anterior testis oval, posterior testis sub-triangular9, transversely oval, entire, in tandem row, contiguous, in posterior third of hindbody2, entire, tandem, contiguous, in posterior third of hindbody2, symmetrical to slightly oblique, close to posterior extremity2, strongly oblique to tandem, in mid-hindbody9, irregular, in posterior hindbody2, mostly intercaecal, distinctly elongate, strongly oblique to slightly tandemUsually 9, in two lateral groups, or one large group in hindbody
Seminal vesicleElongate-oval, nakedTubulo-saccular, naked, long, convolutedNaked, long, convolutedTubularTubulo-saccularTubulo-saccular, in forebodyTubularTubularTubulo-saccular
GonotylAbsentAbsentAbsentAbsentA spined muscular structure immediately anterior to VSAbsentAbsentAbsentAbsent
Genital poreMedian, immediately anterior to VSMedian, immediately anterior to VSMedian, immediately anterior to VSMedian, immediately anterior to VSMedian, immediately anterior to VSMedian, at mid-level of intestinal bifurcation and VSSinistral to VSMedian, immediately posterior to VSMedian, posterior and slightly sininstral to VS
OvaryDextral, pretesticular, regularly lobedOval, pre-testicular, overlapping anterior testisIrregularly subtriangular, pre-testicularEntire, pre-testicular; in posterior hindbodyEntire, anterior to testes in posterior hindbodyEntire, immediately anterosinistral to anterior testisDeeply lobed, median, immediately anterior to testesDeeply lobed, well separated form anterior testis, occupies full width of body in mid-hindbodyDeeply lobed, immediately anterior to testes
UterusFills much of body from intestinal bifurcation to anterior testicular region, mostly intercaecalFills much of hindbody from anterior testis anteriorly, passes dorsally to VS, mostly intercaecalNarrow, reaches between VS and anterior testis, passes dorsally to VS, mostly intercaecalIn hindbody between ovary and VSIn hindbody between ovary and VSIn hindbody, extends close to posterior extremityIn hindbody, between gonads and VSIn hindbody, between VS and anterior testisIn hindbody, extends close to posterior extremity
Vitelline folliclesIn 2 lateral groups from just post intestinal bifurcation to close to posterior extremity, just overlapping caecaIn 2 lateral groups, reach from VS to level distinctly anterior to ovary, just overlapping caeca dorsally and ventrallyIn 2 lateral groups, reach from about halfway between VS and ovary to level of posterior testisIn 2 lateral groups, in hindbody, from slightly posterior to VS to level of anterior testis or mid-bodyIn 2 lateral groups, in hindbody, from slightly anterior to ovary to the posterior extremityIn 2 restricted lateral groups between VS and gonadsIn 2 lateral groups, confluent posteriorly, from level of pharynx to posterior extremityIn 2 bands, occupy full body width from midway between VS to ovary and ovary to anterior testisIn 2 lateral groups, may extend from forebody to level of testes
Excretory vesicleY-shaped, bifurcates lateral to ovary, narrow posteriorly, widens and reaches uterusNot clearNot clearY-shaped, bifurcatedBifurcatedBifurcatedUnknownBifurcatedY-shaped, bifurcated
Excretory vesicle armsMay extend to level of pharynx, excretory pore terminal at posterior end of bodyNot clearNot traced beyond posterior testisReach level of pharynxReach pharynxReach pharynxUnknownReach pharynxReach level of pharynx
HostsFreshwater fishes (Latidae: L. angustifrons, L. mariae, L. microlepis)Freshwater fishes (Latidae: L. angustifrons, L. microlepis)Freshwater fishes (Latidae: L. angustifrons, L. microlepis)Freshwater and marine fishes; reptilesFreshwater fishes (Malapteruridae, Citharinidae and pelicans - probable pseudoparasitism)Marine fishes (Albulidae, Sphyraenidae)Freshwater fishes (Pimelodidae)Marine fishes (Uranoscopidae)Marine fishes
Site in hostImmature specimens in intestine; eggs-bearing specimens in pyloric caeca and gall-bladderIntestineIntestineIntestineIntestineIntestineIntestineIntestineIntestine
DistributionAfrica (Lake Tanganyika)Africa (Lake Tanganyika)Africa (Lake Tanganyika)CosmopolitanAfricaNorth America (Florida, USA)South America (Brazil)JapanAtlantic, Indian and Pacific Oceans
Type-speciesN. tanganyikae (Prudhoe, 1951) Manter & Pritchard, 1969Tanganyikatrema fusiforma n. g., n. sp.Grandifundilamena novemtestes n. g., n. sp.A. spiniceps  (Looss, 1896) Looss, 1899B. pelecani Dollfus, 1950C. longula Overstreet, 1969I. iheringi Travassos, 1947I. mediolecithale Ozaki, 1927S. vinaledwardsii (Linton, 1901) Linton, 1910
  1. Abbreviations: BL, body length; BW, body width; OS, oral sucker; OSW, oral sucker width; VSW, ventral sucker width; VS, ventral sucker