Redescription and life cycle of the monorchiid Postmonorcheides maclovini Szidat, 1950 (Digenea) from the Southwestern Atlantic Ocean: Morphological and molecular data

Bagnato, Estefanía; Gilardoni, Carmen Mariangel; Pina, Susana; Rodrigues, Pedro; Cremonte, Florencia

doi:10.1016/j.parint.2015.09.008

Cited by 10 publications

(6 citation statements)

References 16 publications

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“…Most of these known life cycles are two species-host cycles, as is the case in D. fossor herein for both Lasiotocus species found, which include the use of the same bivalve species as both first and second intermediate host. For rare species of this family, metacercariae may be found within sporocysts [8,10] or may be extruded into the water [57,58]. More typically, however, metacercariae encyst in the tissues of the bivalve, similar to those we observed in D. variabilis and D. fossor.…”

Section: Discussionsupporting

confidence: 76%

“…The high prevalence of L. trachinoti metacercariae in the inhalant siphon of the coquinas compared to the rather rare occurrence of sporocysts in D. fossor supports the contention of Bagnato [8] that a long tail in cercariae suggests a free-living lifestyle. This monorchiid may have a two-host life cycle utilizing the same species of bivalve (in this case, D. fossor) as both first and second intermediate hosts but not the same individuals given the rarity of sporocyst-infected coquinas compared to those harboring metacercariae.…”

Section: Discussionmentioning

confidence: 54%

“…Monorchiidae is a very speciose family [39,66]; however, of the 20 species with a bivalve as intermediate host, only nine have known life cycles: one from the Mediterranean coast [41], one from the European Atlantic coast ( [10]; in [40]), three from the North American Atlantic coast [42,57,58], two from the South American Atlantic coast [8,28], and two from the North American Pacific coast [23,68]. Most of these known life cycles are two species-host cycles, as is the case in D. fossor herein for both Lasiotocus species found, which include the use of the same bivalve species as both first and second intermediate host.…”

Section: Discussionmentioning

confidence: 99%

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Molecular data reshape our understanding of the life cycles of three digeneans (Monorchiidae and Gymnophallidae) infecting the bivalve, Donax variabilis: it’s just a facultative host!

et al. 2021

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The coquina, Donax variabilis, is a known intermediate host of monorchiid and gymnophallid digeneans. Limited morphological criteria for the host and the digeneans’ larval stages have caused confusion in records. Herein, identities of coquinas from the United States (US) Atlantic coast were verified molecularly. We demonstrate that the current GenBank sequences for D. variabilis are erroneous, with the US sequence referring to D. fossor. Two cercariae and three metacercariae previously described in the Gulf of Mexico and one new cercaria were identified morphologically and molecularly, with only metacercariae occurring in both hosts. On the Southeast Atlantic coast, D. variabilis’ role is limited to being a facultative second intermediate host, and D. fossor, an older species, acts as both first and second intermediate hosts. Sequencing demonstrated 100% similarities between larval stages for each of the three digeneans. Sporocysts, single tail cercariae, and metacercariae in the incurrent siphon had sequences identical to those of monorchiid Lasiotocus trachinoti, for which we provide the complete life cycle. Adults are not known for the other two digeneans, and sequences from their larval stages were not identical to any in GenBank. Large sporocysts, cercariae (Cercaria choanura), and metacercariae in the coquinas’ foot were identified as Lasiotocus choanura (Hopkins, 1958) n. comb. Small sporocysts, furcocercous cercariae, and metacercariae in the mantle were identified as gymnophallid Parvatrema cf. donacis. We clarify records wherein authors recognized the three digenean species but confused their life stages, and probably the hosts, as D. variabilis is sympatric with cryptic D. texasianus in the Gulf of Mexico.

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Section: Discussionsupporting

confidence: 76%

Section: Discussionmentioning

confidence: 54%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Molecular data reshape our understanding of the life cycles of three digeneans (Monorchiidae and Gymnophallidae) infecting the bivalve, Donax variabilis: it’s just a facultative host!

et al. 2021

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“…The sporocysts of both infections reported here are consistent with previously reported monorchiid sporocysts (Cremonte et al ., 2001; Gilardoni et al ., 2013; Bagnato et al ., 2016) in being unspecialized, immobile, thick-walled sacs containing cercariae of varying developmental stages. Cercariae from both infections exhibit typical monorchiid cercarial features – two suckers, a pharynx, eye-spots, a thick-walled excretory vesicle, a long, thin tail and lacking a stylet (Cable, 1956).…”

Section: Discussionmentioning

confidence: 99%

Gerricola queenslandensis n. g., n. sp., a new monorchiid trematode from the eastern Australian coast and its life cycle partially elucidated

2021

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Of over 250 species of Monorchiidae Odhner, 1911, just four are known from gerreid fishes. Here, we report adult specimens of a new species infecting Gerres oyena (Forsskål) and Gerres subfasciatus Cuvier from off Heron Island and North Stradbroke Island, Queensland, Australia. The species is morphologically most similar to the concept of Lasiotocus Looss, 1907, which currently comprises eight species, in the possession of an unspined genital atrium, bipartite terminal organ, round oral sucker and unlobed ovary. However, phylogenetic analyses of the 28S ribosomal DNA gene region shows the species to be distantly related to the two sequenced species of Lasiotocus – Lasiotocus mulli (Stossich, 1883) Odhner, 1911 and Lasiotocus trachinoti Overstreet & Brown, 1970 – and that it clearly requires a distinct genus; thus, we propose Gerricola queenslandensis n. g., n. sp. Morphologically, G. queenslandensis n. g., n. sp. differs significantly from L. mulli and L. trachinoti only in the possession of distinctly longer caeca, which terminate in the post-testicular region, and in the absence of a distinct gap in the terminal organ spines. The remaining species of Lasiotocus possess caeca that also terminate in the post-testicular region, which might warrant their transfer to Gerricola n. g. However, doubt about their monophyly due to a combination of significant morphological variation, a lack of information on some features and infection of a wide range of hosts, lead us to retain these taxa as species of Lasiotocus until molecular sequence data are available to better inform their phylogenetic and taxonomic positions. Sporocysts and cercariae of G. queenslandensis n. g., n. sp. were found in a lucinid bivalve, Codakia paytenorum (Iredale), from Heron Island. Sexual adult and intramolluscan stages were genetically matched with the ITS2 ribosomal DNA and cox1 mitochondrial DNA regions. This is the second record of the Lucinidae as a first intermediate host for the Monorchiidae. Additionally, we report sporocysts and cercariae of another monorchiid infection in a tellinid bivalve, Jactellina clathrata (Deshayes), from Heron Island. Molecular sequence data for this species do not match any sequenced species and phylogenetic analyses do not suggest any generic position.

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“…Known monorchiid life cycles consist of three hosts: a molluscan first intermediate host, an invertebrate second intermediate host (usually another mollusc), and a molluscivorous fish definitive host [1,2]. However, the first or second intermediate host is known for only 14 monorchiid species [3][4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Phylogenetic Affinity of Genolopa (Digenea: Monorchiidae) with Descriptions of Two New Species

2020

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The validity of Genolopa Linton, 1910 has been controversial because the observation of presently recognized critical diagnostic morphological features (spines in the genital atrium and a bipartite, anteriorly spined terminal organ) were omitted from the original diagnosis, and these features were not universally appreciated as important diagnostic features until 2008. Modern taxonomists have been further challenged by inappropriate fixation techniques that have resulted in various interpretations of morphological features. Consequently, named species in the genus have fluctuated among other monorchiid genera depending on various interpretations by taxonomists, and a modern consensus on classifying these species is lacking. This study combines a molecular approach with modern conventional morphological techniques to investigate the validity of Genolopa as a lineage within the Monorchiidae. New morphology and molecular sequence data from the type-species of Genolopa were studied, and two new species in the genus were described, Genolopa vesca n. sp. and Genolopa minuscula n. sp. Interrelationships among the Monorchiidae were explored using Bayesian inference analysis of the partial 28S rDNA fragment, incorporating three species of Genolopa for the first time. The phylogenetic analysis revealed that the genus represents a natural lineage, supporting the presence of spines in the genital atrium in conjunction with a bipartite and anteriorly spined terminal organ as key features of the generic diagnosis. This study also provides for the first time partial 28S rDNA data for Postmonorchis orthopristis, Lasiotocus trachinoti, Lasiotocus glebulentus, and an unidentified species of Lasiotocus.

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Redescription and life cycle of the monorchiid Postmonorcheides maclovini Szidat, 1950 (Digenea) from the Southwestern Atlantic Ocean: Morphological and molecular data

Cited by 10 publications

References 16 publications

Molecular data reshape our understanding of the life cycles of three digeneans (Monorchiidae and Gymnophallidae) infecting the bivalve, Donax variabilis: it’s just a facultative host!

Molecular data reshape our understanding of the life cycles of three digeneans (Monorchiidae and Gymnophallidae) infecting the bivalve, Donax variabilis: it’s just a facultative host!

Gerricola queenslandensis n. g., n. sp., a new monorchiid trematode from the eastern Australian coast and its life cycle partially elucidated

Phylogenetic Affinity of Genolopa (Digenea: Monorchiidae) with Descriptions of Two New Species

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