Introduction
The individual parasites in a host population are subsets of the parasite fauna exploiting a host species over its entire geographical range (Poulin, Reference Poulin1997). Therefore, to determine the parasite fauna of a host species, sampling individuals from several localities throughout its geographical distribution range is required. However, most information about the fish parasite fauna in a host species has been gathered from studies analysing the populations from one or two localities. Very few studies have been conducted to describe the parasite fauna across the entire distribution range of a species since this represents a logistical and economic challenge. Host species with a relatively limited distribution offer an opportunity to shorten the knowledge gap about their parasite fauna and to obtain a complete parasite inventory when sample size is large enough to consider the parasite community thoroughly sampled. The full understanding of the fish parasite fauna is relevant because parasites are useful indicators of human impacts on the environment and can be used to infer several aspects about the biology of their hosts (Lafferty, Reference Lafferty1997; Sasal et al., Reference Sasal, Mouillot, Fichez, Chifflet and Kulbicki2007; Williams et al., Reference Williams, MacKenzie and McCarthy1992), as well as about the biodiversity of the ecosystems where parasites and hosts coexist (Marcogliese, Reference Marcogliese2005).
The Ocellated killifish, Floridichthys polyommus, is an endemic fish species occurring mainly in the Yucatán Peninsula. This small-sized fish has been reported from Champotón, Campeche, Mexico, on the coastal shelf of the southern Gulf of Mexico (GM) to Belize, on the Caribbean Sea (Castro-Aguirre et al., Reference Castro-Aguirre, Espinosa-Pérez and Schmitter-Soto1999; Greenfield and Thomerson, Reference Greenfield and Thomerson1997; López-López et al., Reference López-López, Sedeño-Díaz, López-Romero and Trujillo-Jiménez2009). Furthermore, this killifish is one of the most abundant species in the coastal lagoons of the Yucatán Peninsula (Arceo-Carranza et al., Reference Arceo-Carranza, Dorantes-Acereto, Hernández-Mendoza and Chiappa-Carrara2021; Vega-Cendejas et al., Reference Vega-Cendejas and Arreguin-Sanchez1994). The cyprinodontid F. polyommus can be found in a variety of habitats, tolerating anoxic waters and a wide range of salinity conditions (23–110 PSU) and may occur even in the sea (Aguilar-Medrano et al., Reference Aguilar-Medrano, de Santillana and Vega-Cendejas2020; Peralta-Meixueiro and Vega-Cendejas, Reference Peralta-Meixueiro and Vega-Cendejas2011; Vega-Cendejas and Santillana, Reference Vega-Cendejas and Santillana2004; Vega-Cendejas et al., Reference Vega-Cendejas and Arreguin-Sanchez1994).
The metazoan parasite fauna of F. polyommus comprises 26 taxa reported from studies conducted in four localities over an extension of 100 km along the northern coast of the Yucatán state, i.e. Chuburná, Chelem, Celestún, and La Carbonera coastal lagoons. The parasite fauna is composed of 15 digeneans, three nematodes, two cestodes, and one species of monogenean, acanthocephalan, copepod, isopod, hirudinean, and a pentastomid (Espínola-Novelo et al., Reference Espínola-Novelo, Solórzano-García, Guillén-Hernández, Badillo-Alemán, Chiappa-Carrara and Pérez-ponce de León2023; Scholz and Salgado-Maldonado, Reference Scholz and Salgado-Maldonado2001; Scholz et al., Reference Scholz, Vargas-Vázquez, Aguirre-Macedo and Vidal-Martínez1997, Reference Scholz, Aguirre-Macedo and Salgado-Maldonado2001; Sosa-Medina et al., Reference Sosa-Medina, Vidal-Martínez and Aguirre-Macedo2015). The main objectives of this study are to describe the metazoan parasite species richness of F. polyommus across most of its distributional range in the Yucatán Peninsula which encompassed most of their distributional range, including the states of Campeche, Yucatán and Quintana Roo, Mexico; and to provide data on the prevalence and mean intensity of infection of each parasite taxa in the sampled localities to compare the parasite species richness at regional and local scales.
Materials and methods
Four hundred and nine individuals were sampled from six localities across the Yucatán Peninsula, i.e. Champotón (n = 52) in Campeche state; Celestún (n = 127), Dzilam de Bravo (n = 106), and San Felipe (n = 57) in Yucatán state; and Mahaual (n = 33) and Xcalak (n = 34) in Quintana Roo state. Fish were collected in 15 sampling campaigns conducted irregularly between January 2022 and June 2024. Additionally, the dataset was complemented with samples of 94 individuals from three sites of northern Yucatán from the study of Espínola-Novelo et al. (Reference Espínola-Novelo, Solórzano-García, Guillén-Hernández, Badillo-Alemán, Chiappa-Carrara and Pérez-ponce de León2023), i.e. Sisal (n = 34), Homochen (n = 20), and La Carbonera (n = 40) (Figure 1).
Map of the Yucatán Peninsula showing the nine localities where the specimens of Floridichthys polyommus were sampled.
Specimens were captured with cast and seine nets, kept alive in containers, and transported to the laboratory for examination a few hours after capture. Specimens were euthanized following standard procedures of the American Veterinary Medical Association (AVMA [American Veterinary Medical Association], 2020). Each host was measured (total length (TL) in cm) and screened for ectoparasites on the body surface, fins, mouth, gills, and eyes. Fish were dissected, and internal organs were removed from the body cavity, separated in Petri dishes with 0.85% saline, and examined under the stereomicroscope. All recovered parasites were counted in situ; helminths were fixed in nearly boiling 0.85% saline solution and transferred to vials with 100% ethanol. Some specimens were stained with Mayer’s paracarmine and mounted on permanent slides with Canada balsam. Nematodes were cleared with 50% glycerol in semi-permanent slides (Lamothe-Argumedo, Reference Lamothe-Argumedo1997). Crustaceans, including copepods, argulids, and isopods, were fixed in 70% ethanol and, when required, cleared in 50% glycerol for observation under the stereomicroscope.
The identification of parasite taxa was accomplished by using morphological characters, compared to previous studies (Espínola-Novelo et al., Reference Espínola-Novelo, Solórzano-García, Guillén-Hernández, Badillo-Alemán, Chiappa-Carrara and Pérez-ponce de León2023). In a few cases, molecular analyses were carried out to confirm the taxonomic identity of metazoan parasites. Sequences of the 28S rRNA gene were obtained for some individuals following extraction, amplification, and sequencing procedures described in Espínola-Novelo et al. (Reference Espínola-Novelo, Solórzano-García, Guillén-Hernández, Badillo-Alemán, Chiappa-Carrara and Pérez-ponce de León2023). Obtained sequences were checked and edited in Geneious Prime v.11 and submitted to a Basic Local Alignment Search Tool (BLAST, https://blast.ncbi.nlm.nih.gov) for taxonomic identity, considering a species-match when the identity score was higher than 99% with the available records. Novel sequences were deposited at the GenBank with the accession numbers PX056120-PX056128. Voucher specimens of helminth species were deposited at the Colección Nacional de Helmintos (CNHE, Instituto de Biología, Universidad Nacional Autónoma de México, Mexico City) (Table 1).
Metazoan parasites found in Floridichthys polyommus in coastal areas of the Yucatán Peninsula, Mexico
SI, site of infection; DS, developmental stage; Localities: 1, Champotón; 2, Celestún; 3, Dzilam de Bravo; 4, San Felipe, 5, Mahahual; 6, Xcalak. SIS, Sisal; HOM, Homochen; LCA, La Carbonera; CNHE, accession number to the Colección Nacional de Helmintos, UNAM; GB, GenBank accession number.
Site of infection: M, mesentery; I, intestine; B, brain; G, gills; H, heart; Bs, body surface; Mo, mouth; Li, liver; L, larvae; A, adult.
a New host record.
b Published in Espínola-Novelo et al. (Reference Espínola-Novelo, Solórzano-García, Guillén-Hernández, Badillo-Alemán, Chiappa-Carrara and Pérez-ponce de León2023).
Prevalence and mean intensity of infection were calculated for each parasite taxa and locality according to Bush et al. (Reference Bush, Lafferty, Lotz and Shostak1997). In addition, parasite species richness was estimated for each locality at the component community level (all parasite taxa found in a host population). Parasite species accumulation curves were constructed to determine whether or not the sample size was adequate at both, local and regional scales; the species richness estimator Chao2 was also calculated in the ‘vegan’ package of R freeware (Oksanen et al., Reference Oksanen, Simpson, Blanchet, Kindt, Legendre, Minchin, Hara RB, Solymos, Stevens, Szoecs, Wagner, Barbour, Bedward, Bolker, Borcard, Borman, Carvalho, Chirico, De Caceres, Durand, Antoniazi Evangelista, FitzJohn, Friendly, Furneaux, Hannigan, Hill, Lahti, Martino, McGlinn, Ouellette, Ribeiro Cunha, Smith, Stier, Ter Braak and Weedon2025) to determine the expected number of species per population, using 50 permutations.
Results
In total, the analysis comprises 503 individuals of F. polyommus across nine sampling sites. Sample size was variable among localities. Species accumulation curves at the regional and local scales show that, excepting by the locality of San Felipe which clearly reached the asymptote, the curves nearly reached the asymptote in the remaining localities, and also at regional scale, indicating that some species are missing (Figure 2). For instance, at the regional scale, the non-parametric estimator (Chao2) resulted in 29 estimated species, contrasting with the observed richness of 24. At local scale, observed parasite richness varied from 6 to 10, whereas Chao2 values estimated a richness varying from 6.9 to 14.8 (Figure 2). A total of 3,281 individual metazoan parasites belonging to 22 taxa were found (Table 1), including 17 endoparasites (11 as larval stages and six as adults) and five ectoparasites (all as adult stages). Parasite species were identified using morphological characters, and, for 10 taxa, eight trematodes and two cestodes, sequence data of the 28S rRNA gene were obtained to corroborate the identification, bringing the identification to the lowest possible taxonomic level. Four digeneans, i.e. M. microbursa, Phocitremoides ovale, Sinistroporomonorchis bolini, and Stephanostomum tantabiddii were identified to species level with an identity similarity between 99% and 100%. Four trematode taxa reached an identity percentage value between 87.1% and 98%, and were identified only to genus or family level, i.e. Bivesicula sp., Rhipidicotyle sp., Schikhobalotrema sp., and Didymozoidae gen. sp. Two cestodes were sequenced; the metacestode of Anthocephalum sp. reached an identity percentage of 98% with Anthocephalum centrurum; thus, it cannot be considered with certainty to belong to this species, whereas the metacestode of Scyphophyllidium sp. reached an identity percentage of 99.9% with an unidentified species of the genus.
Parasite species accumulation curves of Floridichthys polyommus of the Yucatán Peninsula at both regional and local scales. RO, Observed richness; RE, Expected richness Chao.
The most species-rich group were the digeneans with 13 taxa, followed by cestodes and copepods, with three and two respectively. Conversely, only one taxon was found for Acanthocephala, Nematoda, Malacostraca, Ichthyostraca, Hirudinea, and a Pentastomida (Table 1). Larvae of Contracaecum sp. were present in all sampled localities, whereas the metacestode of Glossocercus caribaensis, and the copepod Ergasilus sp. were found in seven of them. The remaining metazoan parasite taxa were found in 1–6 localities (see Table 1).
Infection parameters
The taxa with the highest prevalence of infection in each sampled locality are different. For instance, the metacestode of G. caribaensis reached the highest prevalence values in La Carbonera and Dzilam de Bravo (50.0%, 83.1%); the copepod Ergasilus sp, in Champotón and Celestún (23.1%, 81.1%); the metacercariae of Ascocotyle diminuta in Sisal and Homechen (57.5%, 34.4%); the digenean Schikhobalotrema sp. in Mahahual (72.7%); Rhipidicotyle sp. in Xcalak (82.3%); and Cardiocephaloides medioconiger in San Felipe (68.4%) (Table 2). However, the intensity of infection was notoriously higher for A. diminuta, particularly in two localities where it was present, reaching mean intensity values of 697.4 and 1129.2 metacercariae per infected fish in Sisal and Homochen, respectively (Table 2).
Prevalence (P %) and mean intensity of infection (MI ± SD) of metazoan parasites of Floridichthys polyommus in coastal areas of the Yucatán Peninsula, Mexico
Parasite fauna at a local scale
The number of parasite taxa was variable among the sampled localities; the localities with the largest number of parasite taxa were La Carbonera, and Dzilam de Bravo, with 10, followed by Champotón, and Celestún with nine, and Homochen, San Felipe, Mahahual, and Xcalak, with eight taxa (Figure 3). The locality with the lowest number of taxa was Sisal, with six.
Proportions of taxonomic groups of metazoan parasites in Floridichthys polyommus of the Yucatán Peninsula at both regional and local scales. PT, number of parasite taxa.
Discussion
Few studies have reported the parasites of the Ocellated killifish in the Yucatán Peninsula; these records account for a limited number of localities in a range of less than 100 Km, i.e. Chelem and Chuburná see (Scholz and Salgado-Maldonado, Reference Scholz and Salgado-Maldonado2001; Scholz et al., Reference Scholz, Vargas-Vázquez, Aguirre-Macedo and Vidal-Martínez1997, Reference Scholz, Aguirre-Macedo and Salgado-Maldonado2001), Celestún (Sosa-Medina et al., Reference Sosa-Medina, Vidal-Martínez and Aguirre-Macedo2015), and La Carbonera (Espínola-Novelo et al., Reference Espínola-Novelo, Solórzano-García, Guillén-Hernández, Badillo-Alemán, Chiappa-Carrara and Pérez-ponce de León2023). Our study is the first assessing the taxonomic composition of the metazoan parasites of the F. polyommus across most of its geographical distribution range, which spans from Champotón (Campeche state) to Xcalak (Quintana Roo state) across the Yucatán Peninsula (Figure 1), encompassing an area of about 1,250 km. (Herrera-Silveira et al., Reference Herrera-Silveira, Comín, Capurro, Rivera, Villalobos-Zapata, Rosado and Azuz2004). Our results add nine new host records to the metazoan parasite fauna of the Ocellated killifish, increasing the total number to 35 taxa.
Parasite species richness
Digeneans were the best represented group of parasites in F. polyommus, with 13 taxa. Six of the 13 digenean taxa are reported for the first time. However, Mesostephanus microbursa, Saccocoelioides sp., and Didymozoidae gen. sp. seem to represent accidental infections since they were found in a single locality with very low prevalence and mean intensity values. Seven out of the 13 digenean taxa were found as metacercariae (Ascocotyle sp., A. diminuta, Cardiocephaloides medioconiger, Clinostomum marginatum, Mesostephanus microbursa, Phocitremoides ovale, and Rhipidicotyle sp.) (Table 1). Of these, Rhipidicotyle sp. must complete its life cycle when fish are consumed by a carnivorous fish, as in other species in bucephalids (see Muñoz et al., Reference Muñoz, Valdivia and López2015). The remaining taxa require a fish-eating bird to complete their life cycles. For instance, species of Cardiocephaloides are mainly parasites of seagulls (Born-Torrijos et al., Reference Born-Torrijos, Poulin, Pérez-del-olmo, Culurgioni, Raga and Holzer2016); in Mexico, adult forms of C. medioconiger have been reported in Larus occidentalis and Larus sp. (Hernández-Mena et al., Reference Hernández-Mena, García-Prieto and García-Varela2014). Species of Clinostomum are parasites of Ciconiiform birds (de León G et al., Reference de León, Garciá-Varela, Pinacho-Pinacho, Sereno-Uribe and Poulin2016; Rosser et al., Reference Rosser, Alberson, Woodyard, Cunningham, Pote and Griffin2017); Ascocotyle diminuta has been reported as a parasite of Paraorygmatobothrium in Celestún, Yucatán (Scholz et al., Reference Scholz, Vargas-Vázquez, Aguirre-Macedo and Vidal-Martínez1997), Ardea albus in Florida (Sepúlveda et al., Reference Sepúlveda, Spalding, Kinsella and Forrester1999), and A. alba in Argentina (Drago and Lunaschi, Reference Drago and Lunaschi2011). The metacercariae of the heterophyd P. ovale was previously reported from F. polyommus by Scholz et al. (Reference Scholz, Aguirre-Macedo and Salgado-Maldonado2001); this species also complete its life cycle in fish-eating birds (Martin, Reference Martin1950) and has been obtained experimentally in chicks and ducks (Scholz et al., Reference Scholz, Aguirre-Macedo and Salgado-Maldonado2001). Finally, the cyathocotylid M. microbursa has been reported in Sula nebouxii (Hernández-Mena et al., Reference Hernández-Mena, García-Varela and Pérez-ponce de León2017).
Molecular data was very useful in establishing or corroborating the identification of four digeneans, i.e. M. microbursa, Phocitremoides ovale, Sinistroporomonorchis bolini, and Stephanostomum tantabiddii whereas other four trematodes, i.e. Bivesicula sp., Rhipidicotyle sp., Schikhobalotrema sp., and Didymozoidae gen. sp. were identified to genus or family level. Floridichthys polyommus is parasitized by three cestode taxa. Glossocercus caribaensis appears to be a common parasite since it was found in seven out of nine localities and has also been reported in previous studies (Espínola-Novelo et al., Reference Espínola-Novelo, Solórzano-García, Guillén-Hernández, Badillo-Alemán, Chiappa-Carrara and Pérez-ponce de León2023; Scholz and Salgado-Maldonado, Reference Scholz and Salgado-Maldonado2001; Sosa-Medina et al., Reference Sosa-Medina, Vidal-Martínez and Aguirre-Macedo2015). The metacestodes of Anthocephalum sp. and Scyphophyllidium sp. were found each in only one locality, Champotón and Mahahual, respectively, exhibiting low prevalence and mean intensity of infection values. Both species close their life cycles when fish are eaten by elasmobranchs (Herzog and Jensen, Reference Herzog and Jensen2018; Jensen and Bullard, Reference Jensen and Bullard2010).
The Ocellated killifish is parasitized only by one species of acanthocephalan, Neoechinorhynchus mexicoensis, which was recorded as cystacanth in three localities and was previously reported by Espínola-Novelo et al. (Reference Espínola-Novelo, Solórzano-García, Guillén-Hernández, Badillo-Alemán, Chiappa-Carrara and Pérez-ponce de León2023) from the same host species. This species has also been reported in freshwater fish such as Dormitator maculatus, Petenia splendida, and Mayaheros urophthalmus (Pinacho-Pinacho et al., Reference Pinacho-Pinacho, Sereno-Uribe, de León and García-Varela2015).
The nematode referred to as Contracaecum sp., was the most common taxa since it was found in all sampling localities, mainly inhabiting the mesentery of F. polyommus, with differences in their prevalence among localities (from 3% to 70%). Even though we considered all specimens of Contracaecum as a single taxon (Contracaecum sp.), they may represent different species (Espínola-Novelo et al., Reference Espínola-Novelo, Solórzano-García, Guillén-Hernández, Badillo-Alemán, Chiappa-Carrara and Pérez-ponce de León2023). As adults, members of Contracaecum are parasites of piscivorous birds and mammals such as seals (Anderson, Reference Anderson2000). No seal species occur in the Yucatan Peninsula; then, piscivorous birds that feed on F. polyommus, such as the Neotropic cormorant, Nannopterum brasilianus; the Boat-billed heron Cochlearius cochlearius; the Reddish egret E. rufescens; the Snowy egret, E. thula; and the Great egret, A. alba (De Dios Arcos et al., Reference De Dios Arcos, Badillo-Alemán, Arceo-Carranza and Chiappa-Carrara2019) could be acting as Contracaecum sp. definitive hosts. The ability of the birds to disperse would explain the presence of Contracaecum sp. in all the localities.
The copepod Ergasilus sp. can be considered a common parasite of F. polyommus, since it was present in seven out of nine localities, reaching prevalence up to 79.5% in some localities. Members of the Genus Ergasilus have been reported in F. polyommus from Celestún and La Carbonera (Espínola-Novelo et al., Reference Espínola-Novelo, Solórzano-García, Guillén-Hernández, Badillo-Alemán, Chiappa-Carrara and Pérez-ponce de León2023; Sosa-Medina et al., Reference Sosa-Medina, Vidal-Martínez and Aguirre-Macedo2015), as well as in other small fish species such as Fundulus grandissimus and F. persimilis in coastal lagoons of the Yucatán Peninsula (Espínola-Novelo et al., Reference Espínola-Novelo, Solórzano-García, Badillo-Alemán, Chiappa-Carrara, Guillén-Hernández and Pérez-ponce de León2025). However, we do not know yet if they represent the same species. Probably, the generalist nature of this parasite allows its presence in several locations. Conversely, Bomolochus sp. represents a rare parasite in the killifish, and constitutes a new record for F. polyommus; however, only one individual was found, suggesting might be an accidental infection. Furthermore, the argulid Argulus sp. and the isopod Cymothoa excisa showed low infection values, but both crustaceans were present in more than one locality; Argulus sp. was found in six, whereas C. excisa was found in two (see Table 1).
Regional vs local parasite species richness patterns
Twenty-four parasite taxa were found as parasites of F. polyommus at the regional scale. The richest localities were La Carbonera and Dzilam de Bravo, with 10 taxa parasitizing F. polyommus. This result showed that the parasites found in a single locality represent a subsample of the total species-richness at the regional level (Figure 3), coinciding with Poulin (Reference Poulin1997) assertion that parasites of a host species in a particular locality do not necessarily represent the entire parasite fauna of the host. This pattern needs to be taken with caution since we acknowledge that species richness estimators showed that a few additional species can be found at both, local and regional scales. Also, as pointed out by Poulin (Reference Poulin1997), new sampling localities may represent new biotic and abiotic conditions and because of that new parasites might be added to the parasite pool. Even though each host population (locality) exhibits a variation in species composition in the sampled localities, four parasite taxa, i.e. C. medioconiger, Contracaecum sp., G. caribaensis, and Ergasilus sp., were found in almost all localities, albeit with varying levels of prevalence and mean intensity of infection (Tables 1 and 2, Figure 3).
Two general patterns were observed at the regional and local scales. First, F. polyommus is mainly parasitized by digeneans which were the most species-rich taxa in all cases, accounting for 54.2% of the parasite taxa. Similarly, digeneans represented 25% to 62.5% of the local parasite fauna in the sampled localities (Figure 4); irrespective of the variable sampling size at local scale, this is a consistent pattern. This pattern coincides with that of other studies. For example, Cribb et al. (Reference Cribb, Bray, Barker, Adlard and Anderson1994) examined 303 species of marine fish from the Great Barrier Reef, Australia and found that digeneans were the dominant gastrointestinal parasites, whereas Poulin (Reference Poulin2016) analysed data from 677 fish species, including 482 from freshwater habitats and 195 from marine habitats, and irrespective of the fact that he uncovered a greater diversification rate of freshwater than marine fish parasites; this author also found digeneans as the dominant parasite group in both environments. A similar pattern was recently found in the study of Espínola-Novelo et al. (Reference Espínola-Novelo, Solórzano-García, Badillo-Alemán, Chiappa-Carrara, Guillén-Hernández and Pérez-ponce de León2025) on two species of killifishes, F. grandissimus and F. persimilis, in coastal lagoons of Yucatán. Likewise, in temperate regions of the Atlantic coast of the USA, Garvey et al. (Reference Garvey, Blanar, Warburton, Grunberg, Mckean and Kerstetter2024) analysed ten species of killifishes of the genus Fundulus spp. to compare the parasite fauna across a latitudinal gradient. These authors found that in 70% of the host populations sampled, digeneans were the dominant parasite group.
Parasite taxa found at both regional and local scales.
A second pattern showed that F. polyommus harbours more taxa of parasites as larval stages than as adults. When each locality is analysed separately, larval forms account for 33.3 to 100% of the parasite communities of F. polyommus. The fact that F. polyommus harbours more parasites as larval forms highlights its role as an intermediate rather than a definitive host. This pattern could be related to its size since small seized fish are more vulnerable to predation than large ones, making them better hosts for larval parasites (Poulin and Leung, Reference Poulin and Leung2011). Most parasite taxa we found in F. polyommus across its distributional range complete their life cycle in fish-eating birds (see references above). In addition, birds are highly vagile can disperse the parasite eggs across localities; this may have determined the widespread presence of some species across the geographic range of this host. In our study, three taxa, i.e. the third-stage larvae of the nematode Contracaecum sp., the metacestodes of G. caribaensis, and the metacercariae of the digenean C. medioconiger were found in most sampled localities. This result suggests that local factors influence the structure of parasite communities.
In conclusion, our results describe the composition of the metazoan parasite fauna infecting the Ocellated killifish across must of its distributional range. Trematodes were the most species-rich group of parasites at both regional and local scale. A group of parasite taxa was commonly found across the distributional range of the host, including the cestode Glossocercus caribaensis, the nematode Contracaecum, and the copepod Ergasilus sp., whereas some species were rare (e.g. the dydymozomid trematode, two larval cestodes, and the copepod Bomolochus), since they only occurred in a single locality. This study provided nine new host records for the Ocellated killifish in the Yucatán Peninsula.
Acknowledgements
JEN thanks SECIHTI for the postdoctoral fellowship ‘Estancias Posdoctorales por México Modalidad Académica’ (CVU 351170), and LAG thanks SECIHTI for the postdoctoral fellowship ‘Estancias Posdoctorales por México Modalidad Académica’ (CVU 640068). We sincerely thank Edith Tapia, Betzi Pérez, and José Sandoval for their assistance in the field and laboratory. We also thank Laura Márquez and Nelly López from the Laboratorio Nacional de Biodiversidad (LANABIO, Biology Institute, UNAM) for their help with DNA sequencing processing and Alfredo Gallardo from BioCon (Laboratorio de Biología de la Conservación, F.C., UNAM) for technical support and the identification of hosts. We also want to thank the anonymous reviewers for their helpful suggestions for improving the manuscript.
Author contributions
JEN: conceptualization, field work, data analyses, writing – original draft. MBA: Field work and host identification. BSG and LAG: Field work and DNA work. SGH: Field work and data analysis. XCC: conceptualization, original draft reviewing, and editing. GPPL: conceptualization, funding, original draft – reviewing and editing. All authors reviewed and accepted the latest version of the manuscript.
Funding
This study was funded by the programmes PAPIIT-UNAM IN200824 to GPPL and IG201121 to XCC, respectively.
Competing interests
None.
Data availability
The authors confirm that the data supporting the findings of this study are available within the article. Specimens were deposited in the National Collection of Helminths, Mexico City. Sequence data was deposited in the GenBank dataset.
