C. R. Biologies 338 (2015) 266–277 Contents lists available at ScienceDirect Comptes Rendus Biologies w ww.sciencedirect.com Taxonomy/Taxinomie Mitochondrial phylogeny of grey mullets (Acanthopterygii: Mugilidae) suggests high proportion of cryptic species La phyloge´nie mitochondriale des mulets (Acanthopterygii: Mugilidae) sugge`re une forte proportion d’espe`ces cryptiques a, b Jean-Dominique Durand *, Philippe Borsa a Institut de recherche pour le de´veloppement (IRD), UMR5119 ECOSYM, Montpellier, France b IRD, UR 227 CoReUs, Noume´a, Montpellier and Denpasar, France A R T I C L E I N F O A B S T R A C T Article history: The low level of morphometric variability and the poor phylogenetic information borne by Received 6 October 2014 the morpho-anatomical characters used thus far in the systematics of grey mullets Accepted after revision 23 January 2015 (Mugilidae) emphasize the utility of molecular systematics in this family. A recent Available online 2 March 2015 mitochondrial phylogeny of grey mullets has uncovered multiple deep lineages within several species, flagging putative cryptic species. Here, we considered that several of the Keywords: deeply divergent lineages represent separate species based on either the tree topology, Molecular taxonomy independent data from nuclear markers, geographic distributions, or a combination of the Revision foregoing. By analogy with these well-documented cases, we considered other deep lineages Chelon in seven genera we focused on to represent putative cryptic species. Up to two cryptic species Crenimugil Dajaus were thus potentially detected in the genus Chelon, three in Crenimugil (including two within Ellochelon the single Crenimugil seheli), two in Dajaus, one in Ellochelon, 16 in Mugil (including 13 within Mugil the single M. cephalus), two in Osteomugil, and 10 in Planiliza. Wherever possible, we kept the Osteomugil current species epithets to designate those lineages that unambiguously correspond to the Planiliza type material, based on type locality, and we assigned arbitrary letters (sp. A, B, etc.) to the other lineages. We present a molecular diagnosis for 24 of the species analysed in this work, as well as for 25 putative cryptic species. ß 2015 Acade´mie des sciences. Published by Elsevier Masson SAS. All rights reserved. R E´ S U M E´ Mots cle´s : Le faible niveau de variabilite´ morphome´trique et la faible information phyloge´ne´tique Taxonomie mole´culaire porte´e par les caracte`res morpho-anatomiques utilise´s a` ce jour dans la syste´matique des Re´vision mulets (Mugilidae) montrent l’inte´reˆt de la syste´matique mole´culaire dans cette famille. Chelon Crenimugil Une phyloge´nie mitochondriale re´cente de la famille des Mugilidae a montre´ de multiples Dajaus ligne´es profondes au sein de plusieurs espe`ces, signalant de possibles espe`ces cryptiques. Ellochelon Ici, nous avons conside´re´ que plusieurs de ces ligne´es profondes repre´sentaient des Mugil espe`ces distinctes en nous basant, soit sur la topologie de l’arbre, soit sur des donne´es Osteomugil ge´ne´tiques nucle´aires obtenues inde´pendamment, soit sur les distributions ge´ographi- Planiliza ques. Par analogie avec ces cas bien documente´s, nous avons examine´ d’autres ligne´es profondes dans sept genres sur lesquels nous avions concentre´ notre effort d’e´chantil- * Corresponding author. Universite´ Montpellier-2, place Euge`ne-Bataillon, 34095 Montpellier cedex 5, France. E-mail address: [email protected] (J.-D. Durand). http://dx.doi.org/10.1016/j.crvi.2015.01.007 1631-0691/ß 2015 Acade´mie des sciences. Published by Elsevier Masson SAS. All rights reserved. J.-D. Durand, P. Borsa / C. R. Biologies 338 (2015) 266–277 267 lonnage d’espe`ces. Jusqu’a` deux espe`ces cryptiques pre´sume´es ont ainsi de´tecte´es dans le genre Chelon, trois dans le genre Crenimugil (dont deux dans le seul C. seheli), deux dans le genre Dajaus, une dans le genre Ellochelon, 16 dans le genre Mugil (dont 13 dans le seul Mugil cephalus), deux dans le genre Osteomugil, et 10 dans le genre Planiliza. Autant que possible, nous avons conserve´ les e´pithe`tes d’espe`ces actuelles pour de´signer les ligne´es qui correspondent clairement au mate´riel-type sur la base de la localite´-type, et nous avons attribue´ des lettres arbitraires (sp. A, B, etc.) aux autres ligne´es. Nous pre´sentons une diagnose mole´culaire pour 24 des espe`ces analyse´es dans le pre´sent travail, ainsi que pour 25 espe`ces cryptiques pre´sume´es. ß 2015 Acade´mie des sciences. Publie´ par Elsevier Masson SAS. Tous droits re´serve´s. 1. Introduction observe or infer from molecular population genetic data. These two properties of species will be the focus of the The determination of species boundaries, one of the present taxonomic review of the Mugilidae. main objectives of taxonomy, is important to evolutionary Based on the only comprehensive, mitochondrial ecology and conservation ecology, because species remain phylogeny of species in the family Mugilidae available the fundamental units and operational entities in most to date [13], the objectives of the present paper are: disciplines in these fields. Species misidentification and species confusion could lead to overestimating genetic to identify deeply divergent mitochondrial lineages that diversity, biasing estimates of genetic differentiation correspond to putative cryptic species in several mugilid between populations, overestimating densities, under- genera; estimating risks of local extinction, or producing mean- to revise the current nomenclature of species by ingless estimates of demographic parameters. This in turn proposing new, provisional names to these lineages; may misguide management actions. A common problem is to provide molecular diagnoses to species and putative that of cryptic species, undetected using traditional cryptic species. taxonomic approaches. Cryptic species are defined as distinct evolutionary Addressing these objectives is a necessary step to clarify lineages with a substantial amount of genetic distinc- the nomenclature of species in the Mugilidae, in a tiveness and no apparent morphological differences [1– taxonomic context where genetic markers are replacing 3]. Highly divergent mitochondrial clades within a traditional morphological characters. nominal species, where within-clade diversity is several times lower than divergence between clades might be 2. Materials and methods caused by either secondary contact, or introgression following interspecific hybridization, or the occurrence 2.1. Rationale of the present systematic revision of hitherto-unrecognized, ‘‘cryptic’’ species. The barcoding literature shows several examples of deep divergence at Durand et al.’s [13] mitochondrial phylogeny of the the mitochondrial cytochrome-oxidase 1 (CO1) locus Mugilidae has uncovered a number of deeply divergent within fish species, which have been ascribed to cryptic lineages within nominal species. Several of the lineages species (e.g., [4–12]). These examples thus illustrate the were paraphyletic with other species; other lineages potential of mitochondrial sequences to flag putative new represented reproductively isolated sympatric species, as species in marine fishes. demonstrated by genotypic frequencies at nuclear loci or The low level of morphometric variability and the poor inferred from karyotypes. Last, in some instances, deeply phylogenetic information borne by the morpho-anatomi- divergent sister-lineages characterized geographically cal characters used so far in the systematics of the grey separate populations within a species. Thus, there was mullets (Actinopterygian fish family Mugilidae) have led to substantial evidence for cryptic species in Mugilidae, based contradictory hence unreliable morphology-based phylog- on the tree topology, on independent data from nuclear enies (reviewed in [13]). This emphasizes the need for markers, and on the geographic distribution of sister molecular systematics in this family. Molecular phyloge- lineages. We used W.N. Eschmeyer’s fish database [17] as netics has demonstrated the occurrence of distinct, deep, the reference for the current nomenclature. The current sometimes paraphyletic mitochondrial lineages in a nomenclature was maintained for a lineage when its proportion of species in the Mugilidae, pointing to the geographic distribution was compatible with the type possible occurrence of cryptic species [13–15]. As a locality of the species. By analogy with these cases where consequence, the species richness of the family Mugilidae specific status was documented, we considered other deep is currently underestimated and possibly largely so. The lineages in Mugilidae, i.e. lineages whose distance to its species concept on which the present revision is based is nearest neighbour exceeded the gap between infra-specific the unified species concept of de Queiroz [16], which views and inter-specific pairwise distances (see section 2.5), to species as separately evolving metapopulation lineages. potentially represent additional cryptic species. We Reciprocal monophyly and reproductive isolation are two maintained the current nomenclature to designate those of the relevant properties of species [16] one expects to lineages that unambiguously correspond to the type 268 J.-D. Durand, P. Borsa / C. R. Biologies 338 (2015) 266–277 material, based on the type locality, and we arbitrarily specimens (including 120 vouchers deposited in museum assigned capital letters to the other lineages. The other collections), was used for the