New evidence for parallel evolution of colour patterns in Malagasy poison frogs (Mantella)

Malagasy poison frogs of the genus Mantella are diurnal and toxic amphibians of highly variable and largely aposematic coloration. Previous studies provided evidence for several instances of homoplastic colour evolution in this genus but were unable to sufficiently resolve relationships among major species groups or to clarify the phylogenetic position of several crucial taxa. Here, we provide cytochrome b data for 143 individuals of three species in the Mantella madagascariensis group, including four newly discovered populations. Three of these new populations are characterized by highly variable coloration and patterns but showed no conspicuous increase of haplotype diversity which would be expected under a scenario of secondary hybridization or admixture of chromatically uniform populations. Several populations of these variable forms and of M. crocea were geographically interspersed between the distribution areas of Mantella aurantiaca and Mantella milotympanum. This provides further support for the hypothesis that the largely similar uniformly orange colour of the last two species evolved in parallel. Phylogenies based on over 2000 bp of two nuclear genes (Rag-1 and Rag-2) identified reliably a clade of the Mantella betsileo and Mantella laevigata groups as sister lineage to the M. madagascariensis group, but did not support species within the latter group as monophyletic. The evolutionary history of these frogs might have been characterized by fast and recurrent evolution of colour patterns, possibly triggered by strong selection pressures and mimicry effects, being too complex to be represented by simple bifurcating models of phylogenetic reconstruction.     

Reinstatement of Rhodotorula colostri (Castelli) Lodder and Rhodotorula crocea Shifrine & Phaff, former synonyms of Rhodotorula aurantiaca (Saito) Lodder

Rhodotorula aurantiaca (Saito) Lodder is an anamorphic basidiomycetous yeast species that belongs to the so-called "Erythrobasidium lineage" of the Urediniomycetes, according to molecular phylogenetic studies based on nucleotide sequence analyses of different ribosomal DNA regions. In the most recent editions of the yeast taxonomy treatises the species Rhodotorula colostri (Castelli) Lodder and Rhodotorula crocea Shifrine & Phaff were listed as synonyms of R. aurantiaca. Taxonomic heterogeneity within R. aurantiaca was demonstrated in a study based on whole-cell protein profiles and is also hinted at by the observed differences in physiological and biochemical characteristics among the different strains under that species name. We determined partial nucleotide sequences of the 26S rRNA gene (D1/D2 domains) of strains maintained in the CBS culture collection under R. aurantiaca, including the type strains of its synonyms. The results showed that R. colostri and R. crocea are clearly distinct from R. aurantiaca and from any other currently recognised basidiomycetous yeast species. Furthermore, phylogenetic analysis of the sequence data placed the former two species in separate lineages of the Microbotryomycetidae: R. colostri in the "ruineniae clade" (Sporidiobolus lineage or Sporidiobolales) and R. crocea loosely linked to Rhodotorula javanica (Microbotryum lineage).     

Emendation of Dioszegia with redescription of Dioszegia hungarica and two new combinations,Dioszegia aurantiaca and Dioszegia crocea

During phylogenetic analyses of hymenomycetous yeasts based on 18S rDNA sequences, we found that Bullera armeniaca showed an extremely close phylogenetic relationship to Cryptococcus hungaricus. The analyses of internal transcribed spacer (ITS) regions of the two yeasts and the phylogenetically related species, Bullera aurantiaca and Bullera crocea, showed that B. armeniaca and C. hungaricus had identical sequences, indicating that these were conspecific. B. aurantiaca and B. crocea also showed high sequence similarity, 97.1% for ITS1, 100% for ITS2, and 98.7% for overall ITS regions. A DNA-DNA reassociation experiment revealed that B. armeniaca and C. hungaricus were conspecific and B. aurantiaca and B. crocea were two distinct species. These species occurred at a phylogenetically different lineage from that of Bulleromyces albus (anamorph: Bullera alba, type species of Bullera) and Filobasidiella neoformans (anamorph: Cryptococcus neoformans, neotype species of Cryptococcus). Based on these results, we emend the genus Dioszegia to include both ballistoconidium-forming and non-ballistoconidium-forming yeasts and redescribe the species Dioszegia hungarica. B. aurantiaca and B. crocea are also transferred to Dioszegia as Dioszegia aurantiaca comb. nov. and Dioszegia crocea comb. nov.     

Mitochondrial evidence for distinct phylogeographic units in the endangered Malagasy poison frog Mantella bernhardi

Mantella bernhardi is an endemic species of Malagasy poison frog threatened by loss and fragmentation of its natural habitat and collection for the pet trade. It is classified as threatened according to the International Union for Conservation of Nature and Natural Resources (IUCN) categories and included in Appendix II of the Convention on the International Trade of Endangered Species (CITES). A recent survey has increased the known distributional range of the species from one to eight populations across southeastern Madagascar, but little is known about its biology and genetic diversity. Here we estimate inter- and intrapopulation mitochondrial genetic variation of four populations. Populations from the northern and southern parts of the distributional range showed a high degree of divergence (maximum of 11.35% in cytochrome b) and were recovered as reciprocally monophyletic groups. Nine haplotypes were detected in the northern and 12 in the southern populations. The population from Ranomafana National Park showed the lowest number of haplotypes and nucleotide diversity, and shared its most common haplotype with the second northern population from Tolongoina. All the other detected haplotypes were unique to each of the four populations. This suggests the existence of important barriers to gene flow, pre-dating human colonization of Madagascar at about 2000 years ago, in distinct contrast to other Mantella species that show a high degree of haplotype sharing throughout their range. The continued habitat fragmentation within the distribution range of M. bernhardi prevents any connection between its populations. Our data indicate the existence of at least two different management units for conservation in this species, corresponding to the North and South of its distribution range, and highlight the existence of strong regional endemism in southeastern Madagascar.     

Genomic variation in the mitochondrially encoded cytochrome b (MT-CYB) and 16S rRNA (MT-RNR2) genes: characterization of eight endangered Pecoran species

In an effort to develop species-specific identification markers, we examined genetic variants and molecular signatures within genes encoding mitochondrial cytochrome b and 16S rRNA in eight endangered Pecoran species endemic to the Indian peninsula. Our results revealed that the cytochrome b gene exhibited higher sequence diversity than the 16S rRNA gene, both between and within species. However, the 16S rRNA gene harboured a larger number of species-specific mutation sites compared with the cytochrome b gene, suggesting that it could be useful for species identification. Indeed, we successfully used 'forensically informative nucleotide sequencing' (FINS) analysis of the 16S rRNA gene to identify two previously unknown biological specimens.     

Genetic variation of an endangered Malagasy frog, <Emphasis Type="Italic">Mantella cowani</Emphasis>, and its phylogeographic relationship to the widespread <Emphasis Type="Italic">M. baroni</Emphasis>

We investigated the degree and distribution of the genetic variation, and phylogeography, of two species of Malagasy poison frogs, Mantella cowani and M. baroni. The former is critically endangered due to its restricted distribution, habitat destruction and overcollection for the pet trade. Analysis of 526 bp of mtDNA (cytochrome b) resulted in separate haplotype networks for the two species, and discovered hybridization at a single locality. The two networks confirm the status of M. baroni and M. cowani as separate evolutionary species and units for conservation. Within both mitochondrial haplotype networks, specimens from different localities shared numerous identical haplotypes, even those from the most distant sample sites of M. baroni. Most populations were characterized by high haplotype diversity and no haplotype clades exclusive to geographical regions were observed. Protection of a few large populations of these species is therefore likely to conserve much of the mtDNA genetic diversity found in the entire species. While M. baroni is widespread and occurs in many nature reserves, we recommend efficient legal protection of some M. cowani habitats to protect this species against extinction.     

Phylogeography of the false smooth snakes, Macroprotodon (Serpentes, Colubridae): mitochondrial DNA sequences show European populations arrived recently from Northwest Africa

Mitochondrial DNA (1075 bp: cytochrome b, 300 bp; 12S rRNA, 393 bp; and 16S rRNA, 382 bp) corroborates the monophyly of the genus Macroprotodon and of the species M. mauritanicus, M. abubakeri, and M. brevis. The subspecies M. brevis ibericus is also monophyletic. The mtDNA tree presented here indicates that M. cucullatus consists of at least two separate units and may possibly represent a primitive morphology rather than a species in its own right. However, this hypothesis is tentative since it is only reflects the history of a single evolutionary unit (mtDNA). A definitive understanding of the evolution of M. cucullatus will not be possible until informative nuclear markers are added to the mitochondrial data. Macroprotodon appears to have originated in the Maghreb region of NW Africa and speciated there around 4-5.5 million years ago around the end of the Miocene period, after which its three main lineages may each have expanded north into more mesic conditions. The group also spread eastwards into coastal areas of Libya quite recently and on to Egypt and Israel. Later still, M. b. ibericus from extreme north Morocco reached the Iberian Peninsula, and M. mauritanicus from Tunisia or Algeria colonised the Balearic Islands of Menorca and Mallorca. Both these range extensions may result from very recent natural colonisations or even from accidental human introduction. Recency of origin of Iberian and Balearic populations is indicated by uniformity of their mtDNA even across large distances, and its great similarity to that of populations in source regions. Isolated populations assigned to M. cucullatus in the Hoggar mountains (southern Algeria) and Western Sahara are probably relicts from quite recent periods of climatic amelioration in the North African desert.     

Systematics of the grey mullets (Teleostei: Mugiliformes: Mugilidae): molecular phylogenetic evidence challenges two centuries of morphology-based taxonomy

The family Mugilidae comprises mainly coastal marine species that are widely distributed in all tropical, subtropical and temperate seas. Mugilid species are generally considered to be ecologically important and they are a major food resource for human populations in certain parts of the world. The taxonomy and systematics of the Mugilidae are still much debated and based primarily on morphological characters. In this study, we provide the first comprehensive molecular systematic account of the Mugilidae using phylogenetic analyses of nucleotide sequence variation at three mitochondrial loci (16S rRNA, cytochrome oxidase I, and cytochrome b) for 257 individuals from 55 currently recognized species. The study covers all 20 mugilid genera currently recognized as being valid. The family comprises seven major lineages that radiated early on from the ancestor to all current forms. All genera that were represented by two species or more, except Cestraeus, turned out to be paraphyletic or polyphyletic. Thus, the present phylogenetic results generally disagree with the current taxonomy at the genus level and imply that the anatomical characters used for the systematics of the Mugilidae may be poorly informative phylogenetically. The present results should provide a sound basis for a taxonomic revision of the mugilid genera. A proportion of the species with large distribution ranges (including Moolgarda seheli, Mugil cephalus and M. curema) appear to consist of cryptic species, thus warranting further taxonomic and genetic work at the infra-generic level.     

Structure and Evolution of the Mitochondrial DNA Complete Control Region in the Lizard <Emphasis Type="Italic">Lacerta dugesii</Emphasis> (Lacertidae,Sauria)

We sequenced the complete control region (CR) and adjacent tRNAs, partial 12S rRNA, and cytochrome b (over 3100 bp) from eight individuals of Madeiran wall lizards, Lacerta dugesii, from four distinct island populations. The tRNAs exhibit a high degree of intraspecific polymorphisms compared to other vertebrates. All CR sequences include a minisatellite that varies in length between populations but is apparently fixed within them. Variation in minisatellite length appears between populations separated by apparently very short evolutionary time spans. Many motifs identified in the CR of other vertebrates are not highly conserved, although conserved blocks are identifiable between the few published reptile CR sequences. Overall there are extensive differences in the internal organization of the reptile CR compared to the more widely studied mammals and birds. Variability in the CR is lower than in cytochrome b, but higher than in 12S rRNA. Phylogenetic analysis of these sequences produces a well-resolved estimate of relationships between populations.     

Discovery of a breeding area of the enigmatic large‐billed reed warbler Acrocephalus orinus

The present study reports the discovery of the hitherto unknown breeding grounds of the large‐billed reed warbler Acrocephalus orinus in the Badakhshan region of Tajikistan. A total of eight adult individuals were caught at three riverine woodland sites and breeding was confirmed at one locality. The identity of the birds was confirmed on the basis of partial sequences of the cytochrome b gene. Even among individuals sampled at the same locality, genetic diversity was surprisingly high. This was interpreted as the result of secondary contact between previously isolated or fragmented populations. The breeding range of the large‐billed reed warbler is likely small and the species’ habitat is under intense pressure from the collection of firewood and fodder. Consequently, the large‐billed reed warbler remains of considerable conservation concern.     

Phylogeny and biogeography of ice crawlers (Insecta: Grylloblattodea) based on six molecular loci: designating conservation status for Grylloblattodea species

Ice crawlers (Insecta: Grylloblattodea) are rarely encountered insects that consist of five genera representing 26 species from North America and Asia. Asian grylloblattids are the most diverse, but North American ice crawlers (genus Grylloblatta) are known for their adaptation to cold conditions. Phylogenetic relationships among grylloblattid species and genera are not known. Six genes were sampled in 35 individuals for 18S rRNA, 28S rRNA, histone 3, 12S rRNA, 16S rRNA, and cytochrome oxidase II from 21 populations of Grylloblatta, three populations from Japan (genus Galloisiana), and three populations from Russia (genus Grylloblattina). Phylogenetic analysis of these data with two mantophasmid outgroups in POY supported monophyletic genera, with Grylloblatta as sister to Grylloblattina. Grylloblatta was shown to contain two major lineages: a clade in Northern California and Oregon and a clade in Washington and Oregon. One new species and six candidate species are proposed. IUCN Red List Conservation Criteria were implemented to designate conservation status for each lineage.     

Molecular phylogenetics of Iberian wall lizards (Podarcis): is Podarcis hispanica a species complex?

Phylogenetic relationships between species and morphotypes of Podarcis wall lizards from the Iberian Peninsula and north Africa were estimated using partial 12S rRNA and cytochrome b mitochondrial DNA sequences. All species except Podarcis hispanica form monophyletic units. P. hispanica is paraphyletic, although all identified morphotypes are monophyletic. These morphotypes represent highly divergent lineages showing 10-15% pairwise sequence divergence with the cytochrome b gene. The data suggest that P. hispanica is a species complex. We recommend using P. hispanica* until additional sampling delimits the number and ranges of species currently referred to P. hispanica. P. carbonelli, which has recently been raised to species status, is confirmed as a genetically distinct form. P. atrata is genetically distinct, but much more closely related to some populations of P. hispanica than previously thought.     

大黄鱼16SrRNA和18SrRNA基因的测定与序列分析

利用多对引物,扩增并测定出大黄鱼16SrRNA基因和18SrRNA基因的部分序列,其长度分别为1202bp和1275bp,16SrRNA基因序列的GC含量为46．12％,18SrRNA基因的Gc含量为53．oo％。将大黄鱼16SrRNA基因序列与GenBank中15种硬骨鱼类的同源序列结合,同时将其18SrRNA基因序列与GenBank中9种脊索动物的同源序列相结合,运用软件获得各自序列间差异百分比,转换和颠换数值等信息。基于这两种基因序列,利用NJ法和BI法,分别构建16种硬骨鱼类和10种脊索动物的分子系统树。18SrRNA构建的系统树包括三大支,一支为哺乳类、鸟类和爬行类共6个物种,一支为两栖类的1个物种,另一支为2种硬骨鱼类。16SrRNA构建的系统树显示大黄鱼所在的石首鱼科与鲈科和盖刺鱼科亲缘关系较近。此外还讨论了这两个基因的序列特征。     

Microbial community of predatory bugs of the genus <Emphasis Type="Italic">Macrolophus</Emphasis>(Hemiptera: Miridae)

BACKGROUND: The predatory mirids of the genus Macrolophus are key natural enemies of various economically important agricultural pests. Both M. caliginosus and M. pygmaeus are commercially available for the augmentative biological control of arthropod pests in European greenhouses. The latter species is known to be infected with Wolbachia -inducing cytoplasmic incompatibility in its host- but the presence of other endosymbionts has not been demonstrated. In the present study, the microbial diversity was examined in various populations of M. caliginosus and M. pygmaeus by 16S rRNA sequencing and denaturing gradient gel electrophoresis. RESULTS: Besides Wolbachia, a co-infection of 2 Rickettsia species was detected in all M. pygmaeus populations. Based on a concatenated alignment of the 16S rRNA gene, the gltA gene and the coxA gene, the first is phylogenetically related to Rickettsia bellii, whereas the other is closely related to Rickettsia limoniae. All M. caliginosus populations were infected with the same Wolbachia and limoniae-like Rickettsia strain as M. pygmaeus, but did not harbour the bellii-like Rickettsia strain. Interestingly, individuals with a single infection were not found. A PCR assay on the ovaries of M. pygmaeus and M. caliginosus indicated that all endosymbionts are vertically transmitted. The presence of Wolbachia and Rickettsia in oocytes was confirmed by a fluorescence in situ hybridisation. A bio-assay comparing an infected and an uninfected M. pygmaeus population suggested that the endosymbionts had minor effects on nymphal development of their insect host and did not influence its fecundity. CONCLUSION: Two species of the palaearctic mirid genus Macrolophus are infected with multiple endosymbionts, including Wolbachia and Rickettsia. Independent of the origin, all tested populations of both M. pygmaeus and M. caliginosus were infected with three and two endosymbionts, respectively. There was no indication that infection with endosymbiotic bacteria had a fitness cost in terms of development and fecundity of the predators.     

Phenotypic and genetic diversity in aposematic Malagasy poison frogs (genus Mantella)

Intraspecific color variation has long fascinated evolutionary biologists. In species with bright warning coloration, phenotypic diversity is particularly compelling because many factors, including natural and sexual selection, contribute to intraspecific variation. To better understand the causes of dramatic phenotypic variation in Malagasy poison frogs, we quantified genetic structure and color and pattern variation across three closely related species, Mantella aurantiaca, Mantella crocea, and Mantella milotympanum. Although our restriction site‐associated DNA (RAD) sequencing approach identified clear genetic clusters, they do not align with current species designations, which has important conservation implications for these imperiled frogs. Moreover, our results suggest that levels of intraspecific color variation within this group have been overestimated, while species diversity has been underestimated. Within major genetic clusters, we observed distinct patterns of variation including: populations that are phenotypically similar yet genetically distinct, populations where phenotypic and genetic breaks coincide, and populations that are genetically similar but have high levels of within‐population phenotypic variation. We also detected admixture between two of the major genetic clusters. Our study suggests that several mechanisms—including hybridization, selection, and drift—are contributing to phenotypic diversity. Ultimately, our work underscores the need for a reevaluation of how polymorphic and polytypic populations and species are classified, especially in aposematic organisms.     

Mitochondrial DNA coding region sequences support the phylogenetic distinction of two Indian wolf species

Two small endangered populations of Indian wolves were recently shown to be distant from other wolf and dog mtDNA lineages characterized so far. None of the inner branches in the tree of canid species based on partial hypervariable D-loop sequences were, however, statistically supported by the data raising the question whether the two Indian wolf lineages represent two new species, occupying an intermediate position between Canis latrans and C. lupus or have diverged from the sub-species of C. lupus due to isolation and drift. Here we report complete D-loop, cytochrome b, and 16S rRNA sequences data for 23 additional wolves from India analysed in the context of other canid species. Extended analyses of D-loop data and partial sequences of 16S rRNA showed highly reticulated pattern and were unable to resolve unambiguously the phylogenetic relationship of Indian wolves among other canid species. The phylogenetic reconstructions of cytochrome b sequences, however gave significant statistical support for the inner branches supporting genetic distinction of the two Indian wolf lineages within themselves as well as from all other wolves of the world, including individuals belonging to subspecies C. lupus chanco and C. lupus pallipes to which the two Indian wolf populations have been traditionally assigned. Their genetic differentiation relative to worldwide variation of wolves supports the suggestion to treat them as separate wolf species, C. himalayensis and C. indica .     

Extreme intraspecific mitochondrial DNA sequence divergence in Galaxias maculatus (Osteichthys: Galaxiidae), one of the world's most widespread freshwater fish

Biogeographic controversies surrounding the widespread freshwater fish, Galaxias maculatus, were addressed with DNA sequence data. Mitochondrial cytochrome b and 16S rRNA sequences were obtained from representatives of six populations of this species. Substantial levels of cytochrome b (maximum 14.6%) and 16S rRNA sequence divergence (maximum 6.0%) were detected between western Pacific (Tasmania-New Zealand) and South American (Chile-Falkland Islands) haplotypes. A considerable level of divergence was also detected between Tasmanian and New Zealand haplotypes (maximum 5.1%) and within and among Chilean and Falkland Island G. maculatus (maximum 3. 8%). The phylogenetic structure of haplotypes conflicts with the accepted pattern of continental fragmentation. Molecular clock calibrations suggest that haplotype divergences postdate the fragmentation of Gondwana. These findings point to marine dispersal rather than ancient vicariance as an explanation for the wide distribution. The phylogenetic structure of South American haplotypes was not consistent with their geographic distribution. We consider factors such as population divergence, population size, dispersal, secondary contact, and philopatry as potential causes of the high level of mtDNA nucleotide diversity in this species.     

Relationships among cave swallow populations (Petrochelidon fulva) determined by comparisons of microsatellite and cytochrome b data

The cave swallow (Petrochelidon fulva) is a polytypic species with isolated populations in northwestern South America, southwestern North America, Yucatan, Greater Antilles, and Florida. We compared microsatellite genotypes of at least five individuals each from five populations and cytochrome b sequence data of two individuals each from seven populations plus two outgroups. Microsatellite allelic diversity was substantial, and the North American populations were about equally variable. In contrast, the Ecuadorian population had far less genetic variation. Gene flow was apparent among populations, especially between Texas and Florida. Genetic structure was greater than in widespread North American species but less than that of sedentary Neotropical birds. Microsatellite genetic distances indicated a close affinity between Ecuadorian and northern populations, especially Texas and Florida, but this finding was inconsistent with cytochrome b data, which indicated that the Ecuadorian population is the clear outgroup to the northern populations. Its outgroup status is consistent with recent classifications that designate South American populations as their own species (P. rufocollaris). The cytochrome b data further suggested that the northern populations are divided into two clades: Texas/Yucatan and Florida/Greater Antilles. The microsatellite data incorrectly measured the diversity and affinities of Ecuadorian birds apparently because of an ascertainment bias that results from the use of heterologous PCR primers. Despite these problems in measuring phylogenetic relationships, the microsatellite data appeared to work well as a population genetic marker in indicating population structure and gene flow.     

Molecular systematics of the genus Megoura (Hemiptera: Aphididae) using mitochondrial and nuclear DNA sequences

To construct the molecular systematics of the genus Megoura (Hemiptera: Aphididae), DNA based-identifi-cation was performed using four mitochondrial and three nuclear DNA regions: partial cytochrome c oxidase I (COI), partial tRNA-leucine + cytochrome c oxidase II (tRNA/COII), cytochrome b (CytB), partial 12S rRNA + tRNA-valine + 16S rRNA (12S/16S), elongation factor-1 alpha (EF1 alpha), and the internal transcribed spacers 1 and 2 (ITS1, ITS2). Pairwise sequence divergences between taxa were compared, and phylogenetic analyses were performed based on each DNA region separately, and the combined datasets. COI, CytB, EF1 alpha, ITS1, and ITS2 were relatively effective in determining species and resolving their relationships. By contrast, the sequences of tRNA/COII and 12S/16S were not able to separate the closely related species. CytB and EF1alpha gave better resolution with higher average sequence divergences (4.7% for CytB, 5.2% for EF1 alpha). The sequence divergence of COI (3.0%) was moderate, and those of the two ITS regions (1.8% for ITS1, 2.0% for ITS2) were very low. Phylogenetic trees were constructed by minimum evolution, maximum parsimony, maximum likelihood, and Bayesian phylogenetic analyses. The results indicated that the phylogenetic relationships between Megoura species were associated with their host preferences. Megoura brevipilosa and M. lespedezae living on Lespedeza were closely related, and M. nigra, monophagous on Vicia venosa, was rather different from M. crassicauda, M. litoralis, and M. viciae, which are oligophagous on Lathyrus and Vicia. The three populations of M. crassicauda formed a clade separated from M. litoralis and M. viciae. Nevertheless M. litoralis and M. viciae, which are morphologically similar, were not separated due to negligible sequence divergence. We discuss the phylogenetic relationships of the Megoura, and the usefulness of the seven DNA regions for determining the species level phylogeny of aphids.     

Cryptic speciation on the high seas; global phylogenetics of the copepod family Eucalanidae

Few genetic data are currently available to assess patterns of population differentiation and speciation in planktonic taxa that inhabit the open ocean. A phylogenetic study of the oceanic copepod family Eucalanidae was undertaken to develop a model zooplankton taxon in which speciation events can be confidently identified. A global survey of 20 described species (526 individuals) sampled from 88 locations worldwide found high levels of cryptic diversity at the species level. Mitochondrial (16S rRNA, CO1) and nuclear (ITS2) DNA sequence data support 12 new genetic lineages as highly distinct from other populations with which they are currently considered conspecific. Out of these 12, at least four are new species. The circumglobal, boundary current species Rhincalanus nasutus was found to be a cryptic species complex, with genetic divergence between populations unrelated to geographic distance. 'Conspecific' populations of seven species exhibited varying levels of genetic differentiation between Atlantic and Pacific basins, suggesting that continental landmasses form barriers to dispersal for a subset of circumglobal species. A molecular phylogeny of the family based on both mitochondrial (16S rRNA) and nuclear (ITS2, 18S rRNA) gene loci supports monophyly of the family Eucalanidae, all four eucalanid genera and the 'pileatus' and 'subtenuis' species groups.