Integrative taxonomy identifies a new species of Phyllodistomum (Digenea: Gorgoderidae) from the twospot livebearer, Heterandria bimaculata (Teleostei: Poeciliidae), in Central Veracruz, Mexico

Abstract

Phyllodistomum inecoli n. sp. is described from the twospot livebearer, Heterandria bimaculata (Teleostei: Poeciliidae), collected in the Río La Antigua basin, Veracruz, Mexico. The new species is described and characterised by using a combination of morphology, scanning electron microscopy, and sequences of nuclear and mitochondrial genes. Diagnostic characters of the new species of Phyllodistomum include a genital pore opening at the level of the caecal bifurcation; oval vitellarium, situated just posterior to the ventral sucker and not extended laterally and anterior extracaecal uterine loops variable in extension (reaching the anterior, median or posterior margin of the ventral sucker). P. inecoli n. sp. most closely resembles P. brevicecum, a species described as a parasite of the central mudminnow, Umbra limi, in other parts of North America; however, the genital pore in P. brevicecum is situated between the caecal bifurcation and the ventral sucker, the ovary is larger, the vitellarium is lobed and extended laterally and the anterior portion of the uterus extends to the posterior margin of the ventral sucker. Comparison of about 1,500–2,200 nucleotides of cox1 and 28S rDNA and ITS1 strongly supports the status of P. inecoli as a new species. Bayesian inference analysis of combined datasets of 28S rDNA and cox1 sequences showed that P. inecoli n. sp. and the other species found in freshwater fishes of Mexico, including the species complex of P. lacustri, are not sister species. Phylogenetic analysis based on 28S rDNA sequences of several gorgoderid taxa revealed the close relationship of P. inecoli n. sp. with several species of Phyllodistomum, Gorgodera and Gorgoderina with cystocercous cercariae developing in sphaeriid bivalves. Dot-plot analysis of ITS1 sequences of P. inecoli n. sp. revealed the presence of eight repetitive elements with different length, which together represent almost half the length of ITS1.

Phyllodistomum kanae sp. nov. (Trematoda: Gorgoderidae), a bladder fluke from the Ezo salamander Hynobius retardatus

“…Recent molecular phylogenetic studies on members of the Gorgoderidae showed that Phyllodistomum is paraphyletic [16,17], as also confirmed in the present study. The broad and foliate hindbody of Phyllodistomum is a key morphological character separating this genus from Gorgoderina and Gorgodera, and furthermore Gorgodera has more testes than Phyllodistomum and Gorgoderina [10].…”

“…Two adult flukes of the new species were individually subjected to DNA Phyllodistomum brevicecum Steen, 1938, a bladder fluke of North American freshwater fish [16], showed the relatively high BLAST scores of 97% identity to 28S rDNA and 87% identity to cox1.…”

Host specificity, molecular phylogeny and morphological differences of Phyllodistomum pseudofolium Nybelin, 1926 and Phyllodistomum angulatum Linstow, 1907 (Trematoda: Gorgoderidae) with notes on Eurasian ruffe as final host for Phyllodistomum spp.

“…of Ginetzinskaya, 1959) P. amnicum Pond near Rybinsk Water Reservoir on River Volga, RussiaKX957730KY307874 Phyllodistomum sp. b (identified as P. pseudofolium ) Perca fluviatilis Rybinsk Water Reservoir on River Volga, RussiaKY307869KY307886 Phyllodistomum macrocotyle a Dreissena polymorpha Lake Vilkokšnis, LithuaniaKJ729518, KJ729522, KJ729526 [27]KJ740518, KJ740519 [27] P. macrocotyle a D. polymorpha Elektrėnai Water Reservoir, LithuaniaKJ729525 [27]KJ740516 [27] P. macrocotyle a D. polymorpha Lake Wigry, PolandKJ729520 [27]KJ740520, KJ740521, KJ740522 [27] P. macrocotyle a D. polymorpha River Shumorovka, RussiaKJ729521, KJ729524 [27]KJ740523 [27] P. macrocotyle a ( = P. folium sensu Sinitsin, 1905) D. polymorpha Lake Lepelskoe, BelarusAY288828 [63]AY288831 [63] P. macrocotyle a ( = P. folium sensu Sinitsin, 1905) D. polymorpha Lake Lukomskoe, BelarusAF533015 [63]AF533015 [63] P. magnificum Tandanus tandanus Moggill Creek, Queensland, AustraliaKF013186, KF013189 [53]KF013153, KF013156 [53] P. inecoli Heterandria bimaculata Agua Bendita, Xico, Veracruz, MexicoKC760199 [8] P. inecoli Profundulus sp.Rio Templo, San Juan del Rio, MexicoKM659389 [10] P. spinopapillatum Profundulus balsanus Rio PuebloViejo, San Gabriel Mixtepec and Rio Santa Cruz, Santiago Jamiltepec, MexicoKM659382, KM659388 [10] P. centropomi Centropomus parallelus Tlacotalpan, Veracruz, MexicoKM659384 [10] P. kanae Hynobius retardatus Pippu, Hokkaido, JapanAB979868 [7] P. brevicecum Umbra limi Brokenhead, Manitoba, Ca...…”

“…While morphology may not be enough to establish robust species delimitation criteria, scanning electron microscopy (SEM) studies have revealed distinct patterns of the distribution of papillae on the body surfaces of species of the family Gorgoderidae [34–37], including species of Phyllodistomum [8–10, 38–43]. These studies have suggested that the arrangements of these tegumental papillae on adult gorgoderid species represent useful taxonomic characters.…”

Molecular approaches to trematode systematics: ‘best practice’ and implications for future study

“…This framework emphasises an integrative approach to taxonomy (Dayrat, 2005;Will et al, 2005) rather than one based on singular criteria, and has already been successfully applied to recognise many trematode species (e.g. Georgieva et al, 2013, Razo-Mendivil et al, 2013Georgieva et al, 2014 in association with Faltýnková et al, 2015;Blasco-Costa et al, 2014 in association with Faltýnková et al, 2014;Herrmann et al, 2014;Diaz et al, 2015). This approach is not completely new to parasite taxonomists, since ecological data (e.g.…”