The blue and red shrimp Aristeus antenantus supports an important commercial fishery in the Western Mediterranean, adjacent Atlantic waters and Mozambique Channel (western Indian Ocean). This study investigates its genetic structure by examining a total of 506 individuals from Mediterranean, Atlantic and Indian Ocean locations. In order to identify putative genetic stocks, sequences from 16S rDNA (546 bp) and COI (514 bp) genes were used. Genetic diversity, estimated by haplotypic and nucleotidic diversity, was lower in the Western Mediterranean than in samples from other locations. The high haplotypic diversity of the Eastern Mediterranean, Atlantic and Indian Ocean samples reflects the occurrence of a number of private haplotypes, which are also responsible for significant genetic divergence between these samples and the Western Mediterranean ones. The analysis of mismatch distributions, neutrality tests, and star-like patterns present in the network of haplotypes provided consistent inference of past population expansion in the Western Mediterranean, Atlantic and Mozambique Channel regions. Our study provides the first evidence of genetic structuring in A. antennatus across its distributional range.KEY WORDS: Aristeus antennatus · COI · 16S rDNA · Genetic structure · Atlantic Ocean · Mediterranean Sea · Western Indian Ocean Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 421: [163][164][165][166][167][168][169][170][171] 2011 roboration of Atlantic-Mediterranean differentiation has been provided by multiple examples of the population structure of marine species, from pioneer work on crustaceans (Chthamalus montagui, Dando & Southward 1981), mollusks (Mytilus galloprovincialis, Quesada et al. 1995a,b; Sepia officinalis, Pérez-Losada et al. 1999) and fishes (Platichthys flesus, Borsa et al. 1997; Merluccius merluccius, Roldán et al. 1998) down to the present day.The blue and red shrimp Aristeus antennatus (Risso, 1816) is an important commercial deep-sea species that inhabits the Mediterranean, northeast Atlantic waters from Portugal to the Cape Verde Islands (Holthuis 1980), and the Indian Ocean from the Maldive Islands to Zanzibar, Mozambique and South Africa (Freitas 1985). In recent years, it has also been recorded off the northern coasts of Brazil (Serejo et al. 2007). A. antennatus is a eurybathic species ranging from 80 to 3300 m depth, with peaks of abundance at 600 to 900 m depth (Campillo 1994, Sardà et al. 2004). Its abundance is also geographically variable, with density in the Western Mediterranean being higher than that in the eastern basin ). Significant morphological differences have been observed in individuals from the 2 basins. However, no allozyme divergence was found (Sardà et al. 1998) and the differences were explained as being a response to hydrological and ecological characteristics of the 2 Mediterranean basins (Sarà 1985). Recently, new molecular markers (microsatellites, Cannas et al. 2008; mitochondrial control region, ...

Systematics derived from morphological characters often does not correspond with the evolutionary processes underlying the divergence within a group of organisms. In the family Mugilidae (Teleostei) morphological similarities have resulted in inconsistencies between taxonomy and phylogeny among its species, and particularly for the genera Mugil, Liza and Chelon where both intrageneric and intergeneric phylogenetic clarifications are needed.

In this paper we addressed the phylogeographical genetic structure of the economically important red shrimp, Aristeus antennatus (Crustacea, Aristeidae) in the Western Mediterranean. Partial mitochondrial regions of the cytochrome c oxidase subunit I (514 bp) and ribosomal 16S subunit (547 bp) were sequenced in 137 individuals collected at three localities: Catalan Sea, Ligurian Sea and the southern Tyrrhenian Sea. Values of haplotypic diversity were h = 0.552-0.724, whereas those for nucleotide diversity were pi = 0.0012-0.0026. Among-sample genetic diversity was not significant and no geographical patterns in the distribution of haplotypes were apparent. Results of the present study are consistent with a past population expansion that occurred <2,000 years ago. Despite the current fishing pressure, genetic variability appears to be sufficiently high to keep A. antennatus populations stable over time. Dispersal-related life history traits may account for the shallow genetic structure. Our results are not in contrast with the hypothesis of sustainability of Western Mediterranean red shrimp fisheries predicted on the basis of previously obtained biological results.

We have characterized a deletion in the MC1R gene causing the loss of one amino acid (p.Phe256del), which is perfectly associated with melanism in guinea fowl (Numida meleagris). Co-segregation of the p.Phe256del with melanism was confirmed in 25 offspring born from a cross of two heterozygote birds; therefore we suggest that this mutation is responsible for the black phenotype. Interestingly, this is the first case of recessive melanism linked to MC1R.

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Understanding life history variation and strategies is crucial for stock assessment and fisheries management due to the direct effects on population dynamics, effective population size, sex-ratios, levels of inbreeding, and relatedness among individuals. Aristeus antennatus (En ─ Blue and red shrimp; Fr ─ Crevette rouge; Sp ─ Gamba rosada) is one of the most exploited demersal resources in the Western Mediterranean Sea. However, information regarding the mating system and mate choice preferences remains largely unknown. Advances in molecular genetic markers and methods of inferring biological relationships among individuals have facilitated new insights into the reproductive dynamics of the species in the wild. Here, we used microsatellite markers to examine the A . antennatus mating system and putative mate choice preferences. Our results provided clear evidence of polyandry and polygyny. Relatedness analyses, together with F ST and DAPC values showed females exhibited a mating bias towards unrelated males. Mating males were inferred from spermatophores and suggested males were sympatric with females and were also from other spawning grounds. Our findings provided the first description of the reproductive behavior of blue and red shrimp.

The early life stages of the blue and red shrimp Aristeus antennatus (Decapoda: Dendrobranchiata: Penaeoidea: Aristeidae) were described by Heldt in 1955 based on plankton samples, larval rearing and assumptions of species habitat. Even with adequate keys, identification of its first larval stages remained a difficult task due to the lack of specific morphological characters which would differentiate them from other Penaeoidea species. Larvae of Aristeus antennatus were collected in the continental slope off the Spanish Mediterranean coast in August 2016 with a neuston net and preserved in ethanol 96%. DNA from the larvae was extracted and the molecular markers Cytochrome Oxidase I and 16S rDNA were sequenced and compared to that of adults with the objective of confirming the previous morphological description. Then, we present additional information to the morphological description of Aristeus antennatus larval stages through scanning electron microscopy and molecular analysis. This represents the first documented occurrence of Aristeus antennatus larvae off the Catalan coast and sets the grounds for further work on larval ecology and population connectivity of the species, which is an important contribution to a more sustainable fishery.

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