Neobenedenia Cibnorensis n. Sp. (Monogenea: Capsalidae), a cryptic species infesting the skin of Seriola rivoliana valenciennes, 1833 (Perciformes: Carangidae) from la ensenada de la paz, baja California Sur, Mexico

Abstract

Ectoparasites of the genus Neobenedenia Yamaguti, 1963, are responsible for causing mortality within aquaculture systems. Given their pronounced morphological resemblance, the identification of Neobenedenia species based on phenotypic characteristics poses significant challenges. Thus, molecular techniques are used to complement discrimination between species with very limited morphological variation, such as Neobenedenia melleni (MacCallum, 1927) Yamaguti 1963 and N. girellae (Hargis, 1955) Yamaguti, 1963. Molecular markers can enhance the ability to describe biological diversity and understand the biogeography of these species.  The gulf of California has traditionally hindered the exchange of genes for various species with different life histories. In this study, Neobenedenia specimens were collected from wild and captive Seriola rivoliana Valenciennes, 1833, at four locations within the gulf of California. Partial sequences of the 28S rDNA and Cytochrome b (Cytb) genes revealed genetic divergence among the specimens. Cytb analysis showed that specimens from cultured S. rivoliana at La Ensenada de La Paz are genetically distinct from N. girellae found in other Pacific Ocean localities. Principal Component Analysis (PCA) also revealed morphometric differences, supporting the recognition of these specimens as a new species, Neobenedenia cibnorensis n. sp. These findings highlight the presence of at least two distinct Neobenedenia species infecting wild and captive S. rivoliana populations within the gulf of California. The integration of molecular and morphometric analyses was key to the accurate identification of these cryptic species and has implications for parasite management and biosecurity in Seriola Cuvier 1816, aquaculture in the region.