Bunocotylid trematodes represent a group of 149 species with a rather complex taxonomic history. The current concept of the subfamily only includes three genera,
Bunocotyle
,
Saturnius
, and
Robinia
.... Specimens of a bunocotylid were collected from the silver mullet,
M. curema
, from a coastal lagoon of Yucatán and identified as belonging to
Saturnius
. Further detailed morphological study revealed they corresponded to
S. maurepasi
, a species previously reported from the stripped mullet,
Mugil cephalus
in Mississippi, USA. Specimens were sequenced for the LSU of nuclear ribosomal RNA gene (28S) to test their phylogenetic position. We discovered that they do not belong in
Saturnius
since they nest as an independent lineage which is the sister taxa of a clade formed by
Robinia
, and
Saturnius
+
Bunocotyle
; additionally, the new genus exhibits high genetic divergence (10-12%) with respect to species allocated in the other bunocotylid genera. The species
S. maurepasi
was then transferred to the new genus as
Parasaturnius maurepasi
n. gen., n. comb.
that was created to accommodate it, and was redescribed based on newly sampled specimens.
Polymorphidae is a monophyletic group of acanthocephalans distributed worldwide. Within this family, Hexaglandula corynosoma is a specialist species that uses a single bird species as a definitive ...host. Southwellina hispida is a generalist species that uses a broad spectrum of definitive hosts to complete its life cycle. In the current research, sequences of cytochrome c oxidase subunit 1 (cox1) from mitochondrial DNA were generated from 44 specimens of H. corynosoma and 76 of S. hispida distributed sympatrically in 6 biogeographic provinces of Mexico with the objective of characterizing and comparing the population genetic structure of 2 acanthocephalan species with opposing life strategies. The phylogeographic studies indicated that the populations of both species lacked a phylogeographic structure and exhibited high haplotype diversity, low nucleotide diversity and low Fst values among the biogeographic provinces; in combination with negative values on the neutrality test, this suggests that the populations of acanthocephalans are expanding. Paratenic hosts are key for the transmission from intermediate to definitive hosts in the generalist species. However, the inclusion of paratenic hosts does not play a principal role in the population genetic structure of S. hispida within its distribution along the coasts of Mexico.
Acanthocephalans of the order Echinorhynchida are one of the most diverse groups in their phylum, with approximately 470 species classified into 11 families that largely consist of parasites of ...freshwater, brackish and marine fishes and, sporadically, reptiles and amphibians distributed worldwide. Previous phylogenies inferred with molecular data have supported the paraphyly or polyphyly of some families, suggesting that most of them have been diagnosed based on unique combinations of characters, rather than shared derivative features. We expand the taxonomic sampling of several genera such as Acanthocephalus, Echinorhynchus and Pseudoacanthocephalus of Echinorhynchidae from diverse biogeographical zones in the Americas, Europe and Asia with the aim of testing the monophyly of the family by using two molecular markers. Sequences from small (SSU) and large (LSU) subunits of ribosomal DNA were obtained for six species representing the genera Acanthocephalus and Echinorhynchus from the Neotropical, Nearctic, Palearctic and Oriental regions. These sequences were aligned with other sequences available in the GenBank dataset from Echinorhynchidae. Phylogenetic trees inferred with the combined (SSU + LSU) and the individual data sets consistently placed the genera Acanthocephalus, Pseudoacanthocephalus and Echinorhynchus into three independent lineages. Two families, Paracanthocephalidae Golvan, 1960, and Pseudoacanthocephalidae Petrochenko, 1956, were resurrected to accommodate the genera Acanthocephalus and Pseudoacanthocephalus, respectively. The species of the genus Acanthocephalus from the Nearctic, Palearctic and Oriental biogeographic regions formed a clade that was well supported. However, Acanthocephalus amini from the Neotropical region was nested inside Arhythmacanthidae. Therefore, the genus Calakmulrhynchus was created to accommodate A. amini and resolve the paraphyly of Acanthocephalus. Finally, the diagnoses of the families Echinorhynchidae and Arhythmacanthidae were amended. The molecular phylogenies should be used as a taxonomic framework to find shared derived characters (synapomorphies) and build a more robust classification scheme that reflects the evolutionary history of the acanthocephalans.
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•Phylogenetic analyses inferred showed that Echinorhynchidae is polyphyletic.•Two families Paracanthocephalidae and Pseudoacanthocephalidae were resurrected.•The diagnoses of the families Echinorhynchidae and Arhythmacanthidae were amended.•The genus Calakmulrhynchus was created to accommodate A. amini and resolve the paraphyly of Acanthocephalus.•Calakmulrhynchus amini n. comb. is a new genus of the family Arhythmacanthidae.
Patagifer
Dietz, 1909 is a small genus of echinostomatids, with 12 recognized species, mostly parasitising threskiornithid birds, distributed worldwide. In the current research, adult specimens of ...the type species,
Patagifer bilobus
(Rudolphi, 1819) Dietz, 1909 from the white faced ibis (
Plegadis chihi
) and white ibis (
Eudocimus albus
) were re-described, providing new metrical data for the number of head collar spines. Those specimens were recorded from eight localities in Mexico and compared morphologically with specimens previously identified as
Patagifer lamothei
. A total of 19 specimens identified as
P. bilobus
including two
hologenophores
were sequenced with three molecular markers: domains D1–D3 of the large subunit (LSU), the internal transcribed spacer (ITS1, ITS2) plus 5.8S from the nuclear rDNA, and nicotinamide adenine dinucleotide dehydrogenase subunit 1 (
nad1
) from mitochondrial DNA. The new sequences were aligned with other sequences of
Patagifer
spp., downloaded from GenBank. Phylogenetic trees inferred from each data set, placed all the specimens in a clade, confirming that the isolates belonged to the same species. The morphological examination of specimens previously identified as
P. lamothei
by Ortega-Olivares MP, Hernández-Mena DI, Pérez-Ponce de León G, García-Varela M (2011) Helminths of the white ibis,
Eudocimus albus
(Aves Therskiornithidae) in Mexico. (Zootaxa 3088, 15–26. 10.11646/zootaxa.3088.1.2) and in combination with molecular data confirms that those specimens should be reassigned to
P. bilobus.
In addition, this is the first study in
P
.
bilobus
using an integrative taxonomy approach.
Adult specimens of monorchiids (Digenea) were collected from the intestines of the white grunt, Haemulon plumierii Lacepède (Haemulidae), and the white mullet, Mugil curema Valenciennes (Mugilidae) ...from five localities off the Yucatán Peninsula and one locality in the Gulf of Mexico. Some specimens were photographed and sequenced for two molecular markers, the large subunit (LSU) of nuclear rDNA and the cytochrome c oxidase subunit 1 (cox1) of mitochondrial DNA. Other specimens were processed for morphological analyses. Newly generated sequences were aligned with other sequences available in GenBank. Bayesian inference and maximum likelihood analyses were implemented using the data sets of LSU and cox1 independently. Reciprocal monophyly evidenced through phylogenetic analyses, sequence divergence values for both molecular markers, and detailed morphological analyses, including scanning electron microscopy photomicrographs, revealed three new genetic lineages, i.e., species, as parasites of M. curema. The three new species are Sinistroporomonorchis mexicanus n. sp., Sinistroporomonorchis yucatanensis n. sp., and Sinistroporomonorchis minutus n. sp. Two additional species of monorchiids were sampled, characterised molecularly, and re-described, namely Sinistroporomonorchis glebulentus (Overstreet, 1971) from the white mullet, and Alloinfundiburictus haemuli (Overstreet, 1969), from the white grunt.
Members of Forticulcitinae Blasco-Costa, Balbuena, Kostadinova & Olson, 2009 include endoparasites of mullet fishes distributed worldwide. Adult specimens were collected from the intestines of white ...mullet (
Mugil curema
) and flathead grey mullet (
Mugil cephalus
) from five localities in the Gulf of Mexico and a single locality in Venezuela.
Photogenophores
were sequenced for two nuclear molecular markers, the large subunit (LSU) and second internal transcribed spacer (ITS2) of nuclear rDNA. The new sequences were aligned with other sequences downloaded from GenBank. The maximum likelihood and Bayesian inferences were deduced using the combined dataset (LSU + ITS2). The phylogenetic analyses revealed four new lineages belonging to Forticulcitinae. Three new species are described in the present study.
Ekuarhuni mexicanus
n. sp.
can be differentiated from its congeneric species by presenting a longer hermaphroditic sac length (136–180 μm) and a wider testis (91–123 μm).
Forticulcita macropharyngis
n. sp.
and
Forticulcita venezuelensis
n. sp.
are the 8th and 9th species described in
Forticulcita
. Both species belong to the diminutive morphotype of
Forticulcita
.
Forticulcita macropharyngis
n. sp.
can be morphologically distinguished from the other congeneric species by the presence of a massive and muscular pharynx (46–110 μm long, 74–106 μm wide).
Forticulcita venezuelensis
n. sp.
is the second species of the studied genus recorded in South America and can be differentiated from congeneric species by possessing the largest testis (138–201 μm long, 83–100 μm wide). Finally, the fourth lineage corresponds to
Overstreetoides
Andrade-Gómez & García-Varela, 2021; however, few specimens of this lineage were collected, precluding any description of the species. In addition, a key is proposed for differentiating the genera and species of Forticulcitinae.
Saccocoelioides is a genus of trematodes associated with fishes from the Americas. In the current research, morphologically distinct specimens of Saccocoelioides spp. were collected from six ...countries in Middle America. Specimens were sequenced using three molecular markers, the domains D1–D3 of the large subunit (LSU) from the nuclear rDNA, the cytochrome c oxidase subunit 1 (cox1) and nicotinamide adenine dinucleotide dehydrogenase subunit 1 (nad1) from mitochondrial DNA. A total of 74 new sequences were compared and aligned with other sequences available in GenBank. Maximum likelihood and Bayesian inference analyses were inferred from the LSU and cox1 datasets, revealing unequivocally that all the specimens correspond to S. lamothei. A haplotype network was built with 119 sequences of the nad1 gene. The network detected 57 distinct haplotypes divided into three haplogroups. To explore morphological differences among samples of S. lamothei, 17 morphological features were measured from 53 specimens from three fish families: Eleotridae, Mugilidae and Gobiidae. Principal component analysis yielded three main polygons that corresponded with each family analysed, suggesting host-induced phenotypic plasticity. The current evidence suggests that S. lamothei infects at least five fish families along the Pacific coasts of Mexico, Guatemala, El Salvador, Honduras, Nicaragua and Costa Rica.
This study investigates the systematic position of some species of the genus Saccocoelioides Szidat, 1954, and the species Culuwiya cichlidorumAguirre-Macedo and Scholz, 2005, from North and Middle ...America using new morphological data and partial sequences of 2 nuclear genes, the large subunit and the internal transcribed spacer 2 from ribosomal DNA. In total 74 specimens representing 4 species of Saccocoelioides (41 of Saccocoelioides sogandaresi, 3 of Saccocoelioides chauhani, 6 of Saccocoelioides lamothei, and 12 of Saccocoelioides olmecae) plus 12 specimens of Culuwiya cichlidorum were analyzed. The phylogenetic analyses inferred with maximum likelihood method and Bayesian inference showed that the 4 species of Saccocoelioides formed a clade divided into 4 subclades representing each species. In addition, 7 specimens sequenced from the type host and locality of Culuwiya cichlidorum were nested in 2 clades: the first clade with specimens of C. cichlidorum from Costa Rica, and the second clade with specimens of S. sogandaresi from Mexico, Honduras, Nicaragua, and Costa Rica. Our analyses suggest that C. cichlidorum should be reallocated into Saccocoelioides, as was originally designated Saccocoelioides cichlidorum n. comb., is restricted to Nicaragua and Costa Rica and associated with cichlid fishes. In contrast, the specimens identified previously as Culuwiya cichlidorum from the coast of Gulf of Mexico by Aguirre-Macedo and Scholz belong to S. sogandaresi, which has a wide distribution that extends from Galveston Bay (U.S.A.) in Gulf of Mexico to Atlantic and Pacific slopes associated with poeciliid and cichlid fishes. New morphological data derived from scanning electron microscopy photographs of the body surface show a characteristic pattern of spination that is useful to distinguish between S. cichlidorum n. comb. and S. sogandaresi.
Members of the genus
Lueheia
Travassos, 1919, are endoparasites of birds, particularly passerines, throughout the Americas. Adults of
Lueheia
sp., (Plagiorhynchidae Golvan, 1960; Porrorchinae Golvan,
...1956
) were recovered from the intestine of the American robin (
Turdus migratorius phillipsi
Bangs) in Mexico City, and two other species of acanthocephalans identified as
Porrorchis nickoli,
(Plagiorhynchidae: Porrorchinae) Salgado-Maldonado and Cruz-Reyes,
2002
and
Centrorhynchus microcephalus
(Bravo-Hollis,
1947
) Golvan,
1956
(Centrorhynchidae Van Cleave, 1916), were recovered from the Virginia opossum (
Didelphis virginiana
Allen) and groove-billed ani (
Crotophaga sulcirostris
Swainson), respectively in southeastern Mexico. Specimens of three species were sequenced at two molecular markers, the small subunit (SSU) and large subunit (LSU) of the nuclear rDNA and compared with other sequences available in GenBank. Maximum likelihood and Bayesian inference analyses of the combined (LSU + SSU) dataset and each individual dataset revealed that the specimens of
Lueheia
sp. formed an independent lineage, which is recognized herein as a new species,
Lueheia aztecae
n. sp., representing the fifth species of the genus in the Americas, and the second in the Nearctic region. The new species can be morphologically distinguished from the other five species in the genus by having a cylindrical proboscis, armed with 24–26 longitudinal rows with 9–10 hooks each. Phylogenetic inference performed with the combined dataset consisting of two genes (LSU + SSU) revealed that
Lueheia aztecae
n. sp. and
P. nickoli
belonging to subfamily Porrorchinae, formed two independent lineages, indicating that the subfamily is paraphyletic.
Porrorchis nickoli
and
C. microcephalus
formed a clade with other species of the genus
Centrorhynchus
, suggesting that
P. nickoli
should be transferred to genus
Centrorhynchus
, to form
C. nickoli
n. comb. In addition, we briefly discuss the ecological associations between the members of the families Plagiorhynchidae and Centrorhynchidae.
Members of the genus
Tylodelphys
Diesing, 1850 are endoparasites of fish-eating birds, particularly ciconiids, anhingids, and podicipedids across the globe. Metacercariae of
Tylodelphys
spp. were ...collected from the cranial and body cavities of freshwater fishes in central and northern Mexico; adults were recovered from the intestine of two species of freshwater diving birds of the family Podicipedidae, commonly known as grebes, in two locations of central Mexico. Specimens were sequenced for two molecular markers, the internal transcribed spacers (ITS1 and ITS2) plus 5.8S gene of the nuclear ribosomal DNA and of the cytochrome
c
oxidase subunit 1 from mitochondrial DNA. The genetic divergence among the 25 samples (16 metacercariae and 9 adults) and between the newly sequenced specimens and those deposited in the GenBank were estimated. Maximum likelihood and Bayesian inference analyses inferred with each data set revealed the existence of five genetic lineages. Eight metacercariae analyzed in this study were nested in two divergent lineages previously recognized as
Tylodelphys
sp. 5 and
Tylodelphys
sp. 6 (sensu Locke et al.,
Int J Parasitol
, 45:841–855,
2015
). Five adult specimens recovered from the intestine of the least grebe (
Tachybaptus dominicus
Linnaeus, 1766) in Tecocomulco Lake, Hidalgo State, nested in a single clade with other sequences identified previously as
Tylodelphys aztecae
, expanding its distribution range in other areas of central Mexico. The isolates of the metacercariae found in the cranial cavity of the shortfin silverside,
Chirostoma humboldtianum
Valenciennes, 1835 from Zacapu Lake in central Mexico formed a monophyletic lineage and were recognized as an undescribed species of
Tylodelphys.
The lack of adult specimens of this lineage in our samples prevented a formal description. However, the metacercariae collected in the cranial cavity of the silverside,
Chirostoma jordani
Woolman, 1894 and the adult specimens recovered from the intestine of the western grebe,
Aechmophorus occidentalis
(Lawrence, 1858) from Cuitzeo Lake formed a monophyletic clade, allowing us to link both stages of the life cycle and to describe this as a new species,
Tylodelphys kuerepus
n. sp. The new species represents the eighth species of the genus described in the Americas and the fourth in the Nearctic region. We briefly discuss the ecological associations between the metacercariae and their second intermediate hosts in relation to the genetic diversity patterns uncovered in our study.
