Biological Sciences

Black nerite snails are ecologically important herbivores of the intertidal zone of Australia's temperate marine coast. A set of 13 microsatellites was developed for the black nerite Nerita atramentosa using 1/8 of a shot-gun pyrosequencing reaction. From 46,971 sequences containing putative microsatellite motifs, 18 were selected for primer design. Thirteen microsatellite loci were successfully genotyped using three multiplex reactions in 45 specimens of black nerite from two localities. The number of alleles per locus varied from four to 23 (mean = 12.4) and the observed heterozygosity ranged from 0.40 to 0.96 (mean = 0.72). Only one locus showed significant deviation from Hardy-Weinberg equilibrium probably due to null alleles. No linkage disequilibrium between pairs of loci was detected. These polymorphic markers represent useful tools for connectivity and seascape genetic studies of Australian black nerites. These studies should provide valuable information for the design and assessment of marine protected areas in temperate waters of Australia.

Siphon limpets are an ecologically important component of the intertidal zone of Australia's temperate coast. Using 1/16 of a shotgun pyrosequencing plate, a set of 14 microsatellites was developed for the Van Diemen's siphon limpet (Siphonaria diemenensis). From 2,744 sequences that contained putative microsatellite motifs, 18 were selected for primer design and tested for amplification. Fourteen microsatellite loci were successfully genotyped in 48 specimens of S. diemenensis from two localities. The number of alleles per locus varied from 5 to 35 (mean = 14.6) and the observed heterozygosity ranged from 0.53 to 0.90 (mean = 0.77). Only one locus showed significant deviation from Hardy-Weinberg equilibrium, probably due to null alleles. No linkage disequilibrium between pairs of loci was detected. Connectivity and seascape genetic studies on siphon limpets using the markers reported here should provide important information for management of temperate Australian marine biodiversity.

The identification of historical, environmental and biological factors influencing metapopulation connectivity is important for informing management policies and for designing conservation areas to protect biodiversity. The brown smooth-hound shark Mustelus henlei is a key component of the Mexican commercial shark fisheries, one of the largest in the world. However, Mexico lacks conservation management policies for this heavily exploited species. We conducted phylogeographic and population genetic analyses using data from mitochondrial and nuclear DNA markers and from oceanographic variables to assess metapopulation connectivity in M. henlei from the Gulf of California and the Pacific coast of Baja California. We report on historical range expansion during the Pleistocene, probably associated with the last stages of formation of the Gulf of California. From a contemporary perspective, there is significant population structure explained by spatial distance (but not by environmental factors), which contrasts with expectations of high dispersal capacity for this shark. Population-and individual-based genetic analyses suggest that both female philopatry and male-biased dispersal impact on metapopulation structure. These results highlight the importance of protecting nursery areas and habitat connectivity for the conservation management of the species. Our study clarifies important biological aspects of the brown smooth-hound shark that have implications for the design of shark management policies and marine protected areas in the Gulf of California, an iconic marine ecosystem of global significance.

Cybium 2006, 30(2): 191-192 (1) Marine Ecology department ,CiCESE, Km107 Carretera tijuana-Ensenada, Ensenada, BC MéxiCo 22860 and Po Box 430222, San diego, Ca 92143-0222, USa. [[email protected]] (2) Elasmobranchs laboratory, Universidad autónoma de Baja California Sur (UaBCS), Carretera al Sur Km 105 la Paz, BCS, MéxiCo.

Cybium 2006, 30(2): 191-192 (1) Marine Ecology department ,CiCESE, Km107 Carretera tijuana-Ensenada, Ensenada, BC MéxiCo 22860 and Po Box 430222, San diego, Ca 92143-0222, USa. [[email protected]] (2) Elasmobranchs laboratory, Universidad autónoma de Baja California Sur (UaBCS), Carretera al Sur Km 105 la Paz, BCS, MéxiCo.

Although the application of population and evolutionary genetic theory and methods to address issues of conservation relevance has a long history, the formalization of conservation genetics as a research field is still relatively recent. One of the periodic catalysts for increased research effort in the field has been advances in molecular technologies, leading to an increasingly wider variety of molecular markers for application in conservation genetic studies. To date, genetic methods have been applied in conservation biology primarily as selectively neutral molecular tools for resolving questions of conservation relevance. However, there has been renewed interest in complementing the analysis of neutral markers with the assessment of loci that may be directly involved in responses to processes such as environmental change, with a view to identifying the genes involved in them. These kinds of studies are now possible due to the increase in availability of genomic resources for nonmodel organisms, and there will likely be an even more rapid increase in the near future due to the advent of new ultrahigh throughput-sequencing technologies. This review considers the implications of the most recent developments in genomic technologies and their potential for contributing to the conservation of populations and species. Three "conservation genomics" case studies are presented (Atlantic salmon, Salmo sala; the butterfly, Melitaea cinxia; and the California condor, Gymnogyps californianus) in order to demonstrate the diversity of applications now possible. While it is clear that genomics approaches in conservation will not replace other tried-and-true methods, these recent developments open up an exciting new range of possibilities that will enable further diversification of the application of genomics in conservation biology.

The aim of this work was the description of fetal mummification in silky shark. During July of 2001 in Santa Maria fishing camp, Gulf of California Mexico, fourteen pregnant female of silky sharks were captured. In all of them the embryos were found to be dehydrated. However, total observations were possible in only two litters. Six embryos in each analyzed litters were found. All the embryos were mummified, complete and without maceration. Because the litters were totally mummificated in several females, it was suggested that fetal mummification was produced by the environmental condition.

This article documents the addition of 512 microsatellite marker loci and nine pairs of Single Nucleotide Polymorphism (SNP) sequencing primers to the Molecular Ecology Resources Database. Loci were developed for the following species: Alcippe morrisonia morrisonia, Bashania fangiana, Bashania fargesii, Chaetodon vagabundus, Colletes floralis, Coluber constrictor flaviventris, Coptotermes gestroi, Crotophaga major, Cyprinella lutrensis, Danaus plexippus, Fagus grandifolia, Falco tinnunculus, Fletcherimyia fletcheri, Hydrilla verticillata, Laterallus jamaicensis coturniculus, Leavenworthia alabamica, Marmosops incanus, Miichthys miiuy, Nasua nasua, Noturus exilis, Odontesthes bonariensis, Quadrula fragosa, Pinctada maxima, Pseudaletia separata, Pseudoperonospora cubensis, Podocarpus elatus, Portunus trituberculatus, Rhagoletis cerasi, Rhinella schneideri, Sarracenia alata, Skeletonema marinoi, Sminthurus viridis, Syngnathus abaster, Uroteuthis (Photololigo) chinensis, Verticillium da...

The northern Mexican Pacific (NMP), the Gulf of California (GC), and Baja California have been recognized as an ecological and evolutionarily dynamic region having experienced significant tectonic and climatic changes leading to the diversification of terrestrial and marine biotas. Zapteryx exasperata is a predominant ray caught in the artisanal fisheries of the NMP. Morphometric and reproductive differences between rays from the GC and the Pacific coast of Baja California (PCBC) regions suggest the presence of distinct populations. We investigate whether this distinction correlates with differences in genetic diversity and differentiation using sequences of the mitochondrial nicotinamide adenine dinucleotide dehydrogenase subunit 2 (ND 2) gene and the noncoding control region (CR) in 63 specimens. Contrary to our expectations, ND 2 bore significantly more diversity (h = 0.76) than CR (h = 0.39). Geographic patterns of diversity of CR were opposite to those of ND 2 , with GC being significantly less (ND 2) and more (CR) diverse than PCBC. The diversity of concatenated haplotypes was high (h = 0.84). Low nucleotide diversity suggests the recent coancestry of haplotypes. Marked genetic structure (Φ st = 0.23, P < 0.0001) revealed the existence of reproductive isolation and limited matrilineal gene flow between GC and PCBC, which correlates with their phenotypic distinction. These results suggest the influence of factors such as female reproductive philopatry, and ecological or historical vicariant barriers to gene flow. Our results point to the existence of a distinct management unit of banded guitarfish in each region, and add to the increasing evidence attesting to the diversifying nature of this evolutionarily dynamic region.

The shovelnose guitarfish Rhinobatos productus is an evolutionarily, ecologically, and economically important ray, with a continuous distribution from San Francisco, California (USA), to Mazatlan, Sinaloa, and in the Gulf of California (Mexico). Regional studies have revealed morphometric differences between shovelnose from the Gulf of California and the Pacific coast of Baja California, which may result from phenotypic plasticity in the presence of high levels of gene flow or from a degree of genetic differentiation in the presence of cryptic isolation within a continuous distribution. We used PCR-RFLP of the mitochondrial control region to assess the degree of genetic differentiation between Gulf of California and Pacific shovelnose guitarfish. We found very high levels of molecular diversity (averages: h=0.77, p=1.19%), which may be associated with historically large and stable populations, as well as very significant levels of genetic differentiation between gulf and Pacific samples (v 2 =64, P<0.0001; F ST =0.63, P<0.0001, mean nucleotide divergence d=2.47%). We found a deep phylogeographic break between haplotypes from the gulf and the Pacific, which may suggest the existence of cryptic species but clearly indicates more than one evolutionarily significant unit of R. productus. Our results show a pattern of genetic structure and levels of differentiation consistent with the geological history of the region. Furthermore, these findings have wideranging implications for the management and conservation of cartilaginous fish in Mexico, as they reveal the existence of biological diversity that will go unnoticed without the genetic scrutiny of intraspecific variation and that is highly relevant for much needed management and conservation efforts.

Crabs of the family Hymenosomatidae are common in coastal and shelf regions throughout much of the southern hemisphere. One of the genera in the family, Hymenosoma, is represented in Africa and the South Pacific (Australia and New Zealand). This distribution can be explained either by vicariance (presence of the genus on the Gondwanan supercontinent and divergence following its break-up) or more recent transoceanic dispersal from one region to the other. We tested these hypotheses by reconstructing phylogenetic relationships among the seven presently-accepted species in the genus, as well as examining their placement among other hymenosomatid crabs, using sequence data from two nuclear markers (Adenine Nucleotide Transporter [ANT] exon 2 and 18S rDNA) and three mitochondrial markers (COI, 12S and 16S rDNA). The five southern African representatives of the genus were recovered as a monophyletic lineage, and another southern African species, Neorhynchoplax bovis, was identified as their sister taxon. The two species of Hymenosoma from the South Pacific neither clustered with their African congeners, nor with each other, and should therefore both be placed into different genera. Molecular dating supports a post-Gondwanan origin of the Hymenosomatidae. While long-distance dispersal cannot be ruled out to explain the presence of the family Hymenosomatidae on the former Gondwanan land-masses and beyond, the evolutionary history of the African species of Hymenosoma indicates that a third means of speciation may be important in this group: gradual along-coast dispersal from tropical towards temperate regions, with range expansions into formerly inhospitable habitat during warm climatic phases, followed by adaptation and speciation during subsequent cooler phases.

Genetic methods can be a powerful tool to resolve the native versus introduced status of populations whose taxonomy and biogeography are poorly understood. The genetic study of introduced species is presently dominated by analyses that identify signatures of recent colonization by means of summary statistics. Unfortunately, such approaches cannot be used in low-dispersal species, in which recently established populations originating from elsewhere in the species' native range also experience periods of low population size because they are founded by few individuals. We tested whether coalescent-based molecular analyses that provide detailed information about demographic history supported the hypothesis that a sea squirt whose distribution is centered on Tasmania was recently introduced to mainland Australia and New Zealand through human activities. Methods comparing trends in population size (Bayesian Skyline Plots and Approximate Bayesian Computation) were no more informative than summary statistics, likely because of recent intra-Tasmanian dispersal. However, IMa2 estimates of divergence between putatively native and introduced populations provided information at a temporal scale suitable to differentiate between recent (potentially anthropogenic) introductions and ancient divergence, and indicated that all three non-Tasmanian populations were founded during the period of European settlement. While this approach can be affected by inaccurate molecular dating, it has considerable (albeit largely unexplored) potential to corroborate nongenetic information in species with limited dispersal capabilities.