The lunule of caligid copepods: an evolutionarily novel structure

Kaji, Tomonari; Maran, Balu Alagar Venmathi; Kondoh, Yuusuke; Ohtsuka, Susumu; Boxshall, Geoff A.; Tsukagoshi, Akira

doi:10.1111/ede.12000

Cited by 12 publications

(8 citation statements)

References 34 publications

(37 reference statements)

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“…Morphologically, Lepeophtheirus differ from Caligus as they lack lunules. Lunules are paired sucker-like structures on the frontal plates that are used for attachment to the fish host, and are unique to nearly half of the genera within the Caligidae, including Caligus and Pseudocaligus [2,26]. Lunules are thought to have evolved only once in the Caligidae and character based phylogenetic analysis of the family suggests that several genera, such as Lepeophtheirus , have secondarily lost their lunules [2].…”

Section: Discussionmentioning

confidence: 99%

Multiple gene analyses of caligid copepods indicate that the reduction of a thoracic appendage in Pseudocaligus represents convergent evolution

2013

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BackgroundThe Caligidae is a family of parasitic copepods containing over 30 recognised genera. They are commercially important parasites as they cause disease in numerous finfish aquaculture facilities globally. Morphological features are used to distinguish between the genera and Pseudocaligus has traditionally been differentiated from Caligus solely by the presence of a much reduced form of the fourth thoracic leg. Currently there are numerous DNA sequences available for Caligus spp. but only the type species, Pseudocaligus brevipedis, has molecular data available, so systematic studies using molecular phylogenetic analyses have been limited.MethodsThree gene regions, SSU rDNA, 16S and CO1, for Pseudocaligus fugu from puffer fish from Japan and Pseudocaligus uniartus from rabbit fish from Indonesia are sequenced and molecular phylogenetic analyses performed in order to infer phylogenetic relationships between Pseudocaligus and other caligid copepods.ResultsThe analysis revealed that there was no discrete grouping of Pseudocaligus spp. and that they had a polyphyletic distribution within Caligus taxa. Pseudocaligus fugu grouped with Caligus elongatus and contained a unique synapomorphy in the SSU rDNA region only seen in members of that clade. Pseudocaligus uniartus formed a well-supported group, in the SSU rDNA analyses, with a Caligus sp. that also infects rabbit fish, but was unresolved in the other analyses. Pseudocaligus brevipedis consistently and robustly grouped with Caligus curtus and C. centrodonti in all analyses. The majority of Lepeophtheirus spp. form a monophyletic sister group to the Caligus clade; however, L. natalensis is unresolved in all analyses and does not form part of the main Lepeophtheirus clade.ConclusionsThese findings do not support the morphological-based distinction between Pseudocaligus and Caligus, suggesting that the reduced fourth leg is a feature that has evolved on multiple occasions throughout caligid evolution. Congruent molecular phylogenetic data support groupings based on the presence of morphological features, such as lunules, geography and host fish type rather than appendage morphology. Therefore, we support the synonymy of Pseudocaligus with Caligus.

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Section: Discussionmentioning

confidence: 99%

Multiple gene analyses of caligid copepods indicate that the reduction of a thoracic appendage in Pseudocaligus represents convergent evolution

2013

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“…The evolutionary processes linked with structural novelties were discussed in several recent studies from a developmental perspective (e.g. Brylski and Hall 1988;Prum 1999;Page 2000;Tsukagoshi 2008, 2010;Nagashima et al 2009;Kaji 2010Kaji , 2012Tajiri et al, 2010;Kaji et al 2011Kaji et al , 2012Atallah et al 2012;Dugon et al 2012). It was clearly shown that the origin of novelties can result from much simple modifications of adjustable elements.…”

Section: Introductionmentioning

confidence: 99%

Parallel evolution of novelties: extremely long intromittent organs in the leaf beetle subfamily Criocerinae

Matsumura

Machida

Wipfler‍

et al. 2013

Evolution and Development

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Extreme elongation of a part of the intromittent organ, the flagellum, has occurred several times in Criocerinae (Chrysomelidae). These leaf beetles have acquired a specialized pocket to store the flagellum in the abdominal cavity, at the same time allowing a quick control of movements of this structure during copulation. We investigated the morphogenesis of the intromittent organs of species with and without a flagellum to discuss the evolutionary background of parallel evolution of novel structures. We found that the specialized pocket is formed by the invagination of an epidermal layer and a resultant rotation of the primary gonopore. Invagination itself is a well-known phenomenon in morphogenetic processes, which leads us to hypothesize that the novelty is formed by co-opting a previously acquired genetic system. A large open-space is present within the intromittent organ during the entire morphogenesis in species without a flagellum, and the invagination in the species with a flagellum grows in the corresponding area. This means that there are no physical impediments for the growth of a large pocket. In addition the sites of muscular attachments in the species with a flagellum are also different from those without it. The differentiation of muscles is completed immediately before adult emergence, which means the muscles are adjustable during the entire morphogenesis in this group. Simple modifications probably based on a co-option of previously acquired genetic systems, the potential space for adding a new element, and an adjustable factor in morphogenesis of the intromittent organ facilitate the parallel evolution of the extreme elongation.

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“…Los copépodos son el segundo grupo parasitario más grande, sobre todo los del género Caligus O. F. Müller, 1785 (Kaji et al, 2012). A pesar de ello, no se mantienen anclados de manera firme y se pierden cuando los hospederos son capturados en el momento de la pesca (Cressey et al, 1983).…”

Section: Resultsunclassified

Parásitos Metazoos Branquiales Del Peto Scomberomorus Cavalla (Cuvier, 1829) en Playa Chachalacas, Veracruz, México

Villar-Beltrán¹,

Valero-Pacheco²,

Méndez³

2020

Neotrop Helminthol

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El peto Scomberomorus cavalla (Cuvier, 1829) es un pez de hábitos oceanódromos, con una ruta migratoria extensa, desde el Sur de Canadá hasta São Paulo, Brasil. En México son escasos los estudios parasitológicos de esta especie, que en el estado de Veracruz es de gran importancia económica entre los meses de mayo a septiembre. El objetivo fue determinar la composición de especies de parásitos metazoos en las branquias de S. cavalla, en la localidad de Chachalacas, Veracruz. Se colectaron 34 branquias entre mayo y julio, obtenidas de las capturas por pesca artesanal. Las branquias se conservaron en formaldehido al 10% y se revisaron para la extracción de los parásitos. En total se obtuvieron 488 individuos, pertenecientes a tres especies de monogéneos (83,2%), cuatro de trematodos (8,4%), dos de copépodos (6,1%) y una de nematodo (2,3%). Los monogéneos presentaron los parámetros de infección más altos: Gotocotyla acanthura (Parona & Perugia, 1896), con una prevalencia del 91,2% y una intensidad media de (5,5±8,3), Mexicotyle mexicana (Meserve, 1938) con 70,6% (5,2±4,4) y Scomberocotyle scomberomori (Koratha, 1955) con 55.9% (5,7±6,6). Este es uno de los pocos trabajos sobre la parasitofauna de S. cavalla en el Golfo de México, obteniéndose nuevos registros, ampliando el rango geográfico de las especies encontradas y generando información útil para futuros estudios.

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The lunule of caligid copepods: an evolutionarily novel structure

Cited by 12 publications

References 34 publications

Multiple gene analyses of caligid copepods indicate that the reduction of a thoracic appendage in Pseudocaligus represents convergent evolution

Multiple gene analyses of caligid copepods indicate that the reduction of a thoracic appendage in Pseudocaligus represents convergent evolution

Parallel evolution of novelties: extremely long intromittent organs in the leaf beetle subfamily Criocerinae

Parásitos Metazoos Branquiales Del Peto Scomberomorus Cavalla (Cuvier, 1829) en Playa Chachalacas, Veracruz, México

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