An integrative approach assesses the intraspecific variations ofProcamallanus(Spirocamallanus)inopinatus, a common parasite in Neotropical freshwater fishes, and the phylogenetic patterns of Camallanidae

Abstract

Integrative taxonomy was used to evaluate two component populations of Procamallanus (Spirocamallanus) inopinatus in Brazil and the phylogeny Camallanidae. Parasite populations were collected in the characiform Anostomoides passionis from River Xingu (Amazon basin) and Megaleporinus elongatus from River Miranda (Paraguay basin). Morphology was analysed using light and scanning electron microscopy (SEM). Genetic characterization was based on partial sequences of the 18S and 28S rDNA, and COI mtDNA. Phylogenies were based on 18S and COI due to data availability. Generalized Mixed Yule Coalescent (GMYC), Poisson Tree Process (PTP) and *BEAST were used for species delimitation and validation. SEM revealed for the first time the presence of minute denticles and pore-like structures surrounding the oral opening, phasmids in females and confirmed other important morphological aspects. Statistical comparison between the two-component populations indicated morphometric variations, especially among males. The different component population of P. (S.) inopinatus showed variable morphometry, but uniform morphology and were validated as conspecific by the GMYC, PTP and *BEAST. Some camallanid sequences in GenBank have incorrect taxonomic labelling. Host, environment and geographic aspects seem to be related to some lineages within Camallanidae; however, their real phylogenetic meanings are still unclear.

Review of the parasitic nematodes of marine fishes from off the American continent

“…in the absence of a supporting scientific publication. Such submissions limit checks on the accuracy of taxonomic identifications, and some likely misidentifications have been noted by some authors (see Černotíková et al ., 2011; Ailán-Choke et al ., 2019, 2020). However, despite the limited and sometimes inaccurate data, the genetic characterization of nematodes reported herein has been crucial for supporting species validity and the evaluation of their phylogenetic positions (Mejía-Madrid and Aguirre-Macedo, 2011 a , 2011 b ; Sardella et al ., 2017; Aguilar-Aguilar et al ., 2019; Sokolov and Gordeev, 2021), genetic variability (Li et al ., 2014), broad phylogenetic studies of higher taxa (Nadler and Hudspeth, 1998, 2000; Nadler et al ., 2007; Li et al ., 2018; Barton et al ., 2022), specific identification of larval forms (Palesse et al ., 2011; Haarder et al ., 2013; Roca-Geronès et al ., 2018) and even the elucidation of life cycles (May-Tec et al ., 2018).…”

Checklist of nematodes parasitizing fish in the Brazilian Amazon

“…; Ancistrus leucostictus; Hemiancistrus sp. intestine Borges et al, 2018 Raphidascaroides brasiliensis Moravec & Thatcher, 1997 b AM; PA Megalodoras uranoscopus (Eigenmann & Eigenmann, 1888); Platydoras costatus (Linnaeus, 1758); Pterodoras granulosus Valenciennes, 1821 intestine Moravec & Thatcher, 1997a; Pereira et al, 2015 a AM; AP Astronotus ocellatus; Corydoras amapaensis Nijssen, 1972; Corydoras ephippifer Nijssen, 1972; Corydoras melanistius Regan, 1912; Corydoras spilurus Norman, 1926; Hyphessobrycon amapaensis Zarske & Géry, 1998; Hyphessobrycon takasei Géry, 1964 intestine Thatcher, 1981; Ferreira et al, 2019; Pereira et al, 2019 (Continued ) Pinto & Noronha, 1976; Santos et al, 1979; Andrade et al, 2001; Andrade & Malta, 2006; Saraiva et al, 2006a; Silva et al, 2011; Gaines et al, 2012; Gonçalves et al, 2014; Tavares-Dias et al, 2014b; Alcântara Dias et al, 2015a, b;Oliveira et al, 2015Hoshino et al, 2016;Santos & Tavares-Dias, 2016;Moreira et al, 2017;Tavares-Dias, 2017;Ferreira et al, 2019;Fujimoto et al, 2018;Negreiros et al, 2019a;Pereira et al, 2019;Carvalho et al, 2020;Ailán-Choke et al, 2020…”