Disentangling the evolutionary and biogeographical history of the freshwater fish trematode genus Creptotrema (Digenea: Allocreadiidae) using an integrative taxonomy approach: the case of Creptotrema agonostomi in Middle American mountain mullets

Abstract

Species of the allocreadiid genus Creptotrema are parasites of freshwater fishes in the Americas. Species in the genus possess one pair of muscular oral lobes on the oral sucker. Currently, the genus contains eight species, six distributed in South America, one in Middle America and one in North America. Genetic data are only available for the North American species, Creptotrema funduli, a parasite of fundulids originally described from Oneida Lake, New York State. In this study, we obtained 28S ribosomal DNA sequences of trematodes morphologically similar to Creptotrema agonostomi from the mountain mullet, Dajaus monticola, across a wide geographical range in Middle America. Our molecular phylogenetic analyses showed that (1) the genus Creptotrema, as currently conceived, is not monophyletic; (2) the allocreadiids in mountain mullets should be re-allocated in the genus Pseudoparacreptotrema; and (3) the allocreadiid trematodes from D. monticola across Middle America represent four morphologically similar species, three of which can be distinguished genetically. These three new species are described herein using an integrative taxonomy approach. We contend that accurate estimates of species diversity and phylogenetic relationships among allocreadiids, and most likely other species of trematodes, necessarily require an integrative taxonomy approach that should consider at least DNA sequences and scanning electron microscopy.

Three new species of Creptotrema (Trematoda, Allocreadiidae) with an amended diagnosis of the genus and reassignment of Auriculostoma (Allocreadiidae), based on morphological and molecular evidence

“…According to our 28S rDNA phylogenetic inference (see Results section), the sequence of C. funduli was not grouped within the Creptotrema sensu stricto clade. Considering that this sequence was not sourced from the type-host or type-locality [ 15 , 46 ], we hypothesize that the specimen might not belong to Creptotrema and may represent a new genus yet to be properly described, corroborating the paraphyly of the genus recently proposed by Pérez-Ponce de León et al [ 46 ]. After analyzing the types deposited in museums and based on our molecular data, C. funduli is proposed herein as species inquirenda ; future studies must be conducted to resolve its taxonomic status.…”

“…(considering the species previously allocated in Auriculostoma ), and represents a shared feature among other “papillose” allocreadiids as a result of convergent evolution. Therefore, this character should not be considered sufficient to delimitate and distinguish species of Creptotrema or genera of “papillose” allocreadiids, since this character arose or was secondarily lost several times during the evolutionary history of the group [ 46 ]. We recommend the use of different tools for consistent morphological and molecular analyses to diagnose the species.…”

“…Species of this genus parasitize freshwater teleosts belonging to the family Anostomidae in Brazil. There are currently seven valid species in this genus [ 26 ] (excluding Creptotrema agonostomi Salgado-Maldonado, Cabañas-Carranza & Caspeta-Mandujano, 1978, recently reassigned as Pseudoparacreptotrema Pérez Ponce de León, Pinacho-Pinacho, Mendoza-Garfias, Choudhury & García-Varela, 2016 [ 46 ]), described as parasites of teleosts in the United States, Brazil, Ecuador, Paraguay, and Argentina, and toads (Bufonidae) from Colombia.…”

Description of a new species ofAuriculostoma(Digenea: Allocreadiidae) fromCharacidium heirmostigmata(Characiformes: Crenuchidae) from Argentina, using morphological and molecular data

“…The results of the molecular analysis further corroborated the independence of the new species. The topology of the phylogenetic tree, regarding on the position of Auriculostoma, Creptotrematina and Wallinia, agrees with previous studies by Curran et al (2011), Razo-Mendivil et al (2014 and Alves Dias et al (2020), but disagrees with Pérez-Ponce de León et al (2015), Hernández-Mena et al (2016, 2019 and Da Silva et al (2021). There is no doubt about the monophyly of each genus, but the phylogenetic relationships between them are not well supported and require further scrutiny.…”

“…The family Allocreadiidae Looss, 1902 is distributed worldwide and their members are mainly parasites of the digestive tract of freshwater fishes (see Caira & Bogéa, 2004). The studied specimens belong to a group of nine genera of allocreadiids characterized by having muscular lobes associated with the oral sucker, including Acrolichanus Ward, 1917; Auriculostoma Scholz, Aguirre-Macedo & Choudhury, 2004; Crepidostomum Braun, 1900; Creptotrema Travassos, Artigas & Pereira, 1928; Creptotrematina Yamaguti, 1954; Bunodera Railliet, 1896; Bunoderella Schell, 1964; Megalogonia Surber, 1928; and Pseudoparacreptotrema Pérez Ponce de León, Pinacho-Pinacho, Mendoza-Garfias, Choudhury & García-Varela, 2016 (Atopkin et al ., 2020; Pérez-Ponce de León et al ., 2020). However, our specimens conform with the diagnosis of the genus Auriculostoma in that they possess a single pair of oral lobes, funnel-shaped oral sucker and pretesticular uterus.…”