Genetic and Morphological Evidence to Split the Coris julis Species Complex (Teleostei: Labridae) Into Two Sibling Species: Resurrection of Coris melanura (Lowe, 1839) Redescription of Coris julis (Linnaeus, 1758)

Sergio Ramírez-Amaro,Ignacio Bolado,Francesc Ordines,Ronald Fricke,Enric Massutí,Ignacio Ruiz-Jarabo

doi:10.3389/fmars.2021.744639

Abstract

The genus Coris contains 28 valid species, most of them with an Indo-Pacific distribution and only two species recognized from the eastern Atlantic: Coris atlantica and C. julis. This last species has a large variability in its coloration, which caused that during the first half of XIX century the sexes were considered as different species. Two liveries have been described for C. julis: (i) primary or “giofredi,” which corresponds to females and primary-phase males and is considered common for Atlantic and Mediterranean populations; and (ii) the secondary or “julis” which corresponds to secondary-phase males, which is different for Atlantic and Mediterranean populations. In this study we demonstrate the existence of two sibling species within the C. julis species complex. Morphological and molecular analyses showed that this species complex is composed of two species: (i) C. julis, distributed mainly in the Mediterranean, from which the species was originally described; and (ii) C. melanura, a species described by Lowe in 1839 which is resurrected here, mainly distributed in the eastern Atlantic and western Mediterranean. We also discuss the possible speciation event to understand the contemporary distribution patterns of Coris species in the eastern Atlantic and Mediterranean.

Highlights

The accurate delineation of species is of paramount importance to quantify and preserve biodiversity
Our morphological and molecular analyses confirmed the hypothesis that Coris julis is a species complex composed of two sibling species: C. julis, distributed mainly in the Mediterranean, from which the species was originally described, and C. melanura (Lowe, 1839), that we propose as a valid species with the oldest available name, distributed mainly in the northeastern Atlantic and western Mediterranean
The differences in the secondary livery between Atlantic and Mediterranean morphotypes had already been documented (e.g., Sanchez-Delgado, 1981; Michel et al, 1987; Laurent and Lejeune, 1988; Martino and Grau, 2010), this is the first time that differences in the primary livery are reported

Summary

Introduction

The accurate delineation of species is of paramount importance to quantify and preserve biodiversity. This process is difficult when trying to tell apart closely related taxa (Mayr, 1947; Coyne and Orr, 2004). Coris julis (Linnaeus, 1758), reported from the northeastern Atlantic and the Mediterranean, and Coris atlantica Günther, 1862, reported from the African Atlantic coast, are currently the only two species representing this genus outside the Indo-Pacific (Randall, 1999; Parenti and Randall, 2018). Most species of Coris are beautifully colored, to the point that Günther (1880) said they “belong to the most gorgeously colored kinds of the whole class of fishes.” The color pattern is of great diagnostic importance in the genus, but the radical changes of color that occur with sex change frequently led to incorrectly describing different species for each color phase (Randall, 1999)

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