Harnessing eDNA metabarcoding to investigate fish community composition and its seasonal changes in the Oslo fjord.

In the face of global ecosystem changes driven by anthropogenic activities, effective biomonitoring strategies are crucial for mitigating impacts on vulnerable aquatic habitats. Time series analysis underscores a great significance in understanding the dynamic nature of marine ecosystems, especially amidst climate change disrupting established seasonal patterns. Focusing on Norway's Oslo fjord, our research utilises eDNA-based monitoring for temporal analysis of aquatic biodiversity during a one year period, with bi-monthly sampling along a transect. To increase the robustness of the study, a taxonomic assignment comparing BLAST+ and SINTAX approaches was done. Utilising MiFish and Elas02 primer sets, our study detected 63 unique fish species, including several commercially important species. Our findings reveal a substantial increase in read abundance during specific migratory cycles, highlighting the efficacy of eDNA metabarcoding for fish composition characterization. Seasonal dynamics for certain species exhibit clear patterns, emphasising the method's utility in unravelling ecological complexities. eDNA metabarcoding emerges as a cost-effective tool with considerable potential for fish community monitoring for conservation purposes in dynamic marine environments like the Oslo fjord, contributing valuable insights for informed management strategies.

Hybrid speciation driven by multilocus introgression of ecological traits.

Hybridization allows adaptations to be shared among lineages and may trigger the evolution of new species1,2. However, convincing examples of homoploid hybrid speciation remain rare because it is challenging to demonstrate that hybridization was crucial in generating reproductive isolation3. Here we combine population genomic analysis with quantitative trait locus mapping of species-specific traits to examine a case of hybrid speciation in Heliconius butterflies. We show that Heliconius elevatus is a hybrid species that is sympatric with both parents and has persisted as an independently evolving lineage for at least 180,000 years. This is despite pervasive and ongoing gene flow with one parent, Heliconius pardalinus, which homogenizes 99% of their genomes. The remaining 1% introgressed from the other parent, Heliconius melpomene, and is scattered widely across the H. elevatus genome in islands of divergence from H. pardalinus. These islands contain multiple traits that are under disruptive selection, including colour pattern, wing shape, host plant preference, sex pheromones and mate choice. Collectively, these traits place H. elevatus on its own adaptive peak and permit coexistence with both parents. Our results show that speciation was driven by introgression of ecological traits, and that speciation with gene flow is possible with a multilocus genetic architecture.

Convergent and environmentally associated chromatic polymorphism in Bryconops Kner, 1858 (Ostariophysi: Characiformes: Iguanodectidae).

Bryconops Kner, 1858, includes two well defined subgenera based on morphological evidence, with each containing at least one species (B. (Bryconops) caudomaculatus and B. (Creatochanes) melanurus) with a very wide distribution, within which regional populations present color variations. To test if phenotypic variation is related to cladogenetic events, we performed tests for phylogenetic independence and determined the strength of convergence for color characters in relation to water type, as the variation between clear, black and white waters is considered to be one of the major driving forces in the evolution of Amazonian fishes. Color characters for fins above the median line of the body were generally found to be independent from phylogeny and the Wheatsheaf test strongly supports convergence of the dorsal fin color between populations of species in the same type of water, with a similar trend suggested for the color of the dorsal lobe of the caudal fin. This means that simple color characters cannot necessarily be relied upon for taxonomic revisions of the genus as local phenotypic variants may represent environmentally determined plasticity or convergent evolution. Further studies are required to determine the validity of these characters.

Molecular analyses of carangid fish diets reveal inter-predation, dietary overlap, and the importance of early life stages in trophic ecology.

Carangid fishes are commercially important in fisheries and aquaculture. They are distributed worldwide in both tropical and subtropical marine ecosystems. Their role in food webs is often unclear since their diet cannot be easily identified by traditional gut content analysis. They are suspected to prey on pelagic and benthic species, with clupeiform fishes being important dietary items for some species, though it is unknown whether carangids share food resources or show trophic segregation. Here, we used metabarcoding to overcome traditional challenges of taxonomic approaches to analyze the diet of seven carangid species caught as bycatch in the Brazilian southwest Atlantic sardine fishery. Stomach contents were processed from the following species: Caranx crysos, Caranx latus, Chloroscombrus chrysurus, Hemicaranx amblyrhynchus, Oligoplites saliens, Selene setapinnis, and Trachinotus carolinus. Identified diets were dominated by teleost fishes. The C. latus diet was the most distinct among the seven species, preferentially consuming Engraulis anchoita, but H. amblyrhynchus, O. saliens, and S. setapinnis also showed a trend of predominantly consuming small pelagic fishes. Finally, we found evidence of inter-predation in carangids, especially strong between S. setapinnis and C. crysos, suggesting that consumption of early life stages may result in indirect competition through reduced recruitment in these fishes. These findings provide unprecedented insights into the biodiversity in marine ecosystems, especially the poorly known diet of carangid fishes.

Merging two eDNA metabarcoding approaches and citizen-science-based sampling to facilitate fish community monitoring along vast Sub-Saharan coastlines.

The coastline of Sub-Saharan Africa hosts highly diverse fish communities of great conservation value, which are also key resources for local livelihoods. However, many costal ecosystems are threatened by overexploitation and their conservation state is frequently unknown due to their vast spatial extent and limited monitoring budgets. Here, we evaluated the potential of citizen science-based eDNA surveys to alleviate such chronic data deficiencies and assessed fish communities in Mozambique using two 12S metabarcoding primer sets. Samples were either collected by scientific personnel or trained community members and results from the two metabarcoding primers were combined using a new data merging approach. Irrespective of the background of sampling personnel, a high average fish species richness was recorded (38 ± 20 OTUs per sample). Individual sections of the coastline largely differed in the occurrence of threatened and commercially important species, highlighting the need for regionally differentiated management strategies. A detailed comparison of the two applied primer sets revealed an important trade-off in primer choice with MiFish primers amplifying a higher number of species but Riaz primers performing better in the detection of threatened fish species. This trade-off could be partly resolved by applying our new data-merging approach, which was especially designed to increase the robustness of multiprimer assessments in regions with poor reference libraries. Overall, our study provides encouraging results but also highlights that eDNA-based monitoring will require further improvements of, for example, reference databases and local analytical infrastructure to facilitate routine applications in Sub-Saharan Africa.

Scale-dependent environmental effects on phenotypic distributions in Heliconius butterflies.

Identifying the relative importance of different mechanisms responsible for the emergence and maintenance of phenotypic diversity can be challenging, as multiple selective pressures and stochastic events are involved in these processes. Therefore, testing how environmental conditions shape the distribution of phenotypes can offer important insights on local adaptation, divergence, and speciation. The red-yellow Müllerian mimicry ring of Heliconius butterflies exhibits a wide diversity of color patterns across the Neotropics and is involved in multiple hybrid zones, making it a powerful system to investigate environmental drivers of phenotypic distributions. Using the distantly related Heliconius erato and Heliconius melpomene co-mimics and a multiscale distribution approach, we investigated whether distinct phenotypes of these species are associated with different environmental conditions. We show that Heliconius red-yellow phenotypic distribution is strongly driven by environmental gradients (especially thermal and precipitation variables), but that phenotype and environment associations vary with spatial scale. While co-mimics are usually predicted to occur in similar environments at large spatial scales, patterns at local scales are not always consistent (i.e., different variables are best predictors of phenotypic occurrence in different locations) or congruent (i.e., co-mimics show distinct associations with environment). We suggest that large-scale analyses are important for identifying how environmental factors shape broad mimetic phenotypic distributions, but that local studies are essential to understand the context-dependent biotic, abiotic, and historical mechanisms driving finer-scale phenotypic transitions.

Revisiting the phylogeny of the genus Lolliguncula Steenstrup 1881 improves understanding of their biogeography and proves the validity of Lolliguncula argus Brakoniecki & Roper, 1985.

The biogeography of American loliginid squids has been improved in recent years, but certain key taxa have been missing. Given that the most accurate phylogenies and estimates of divergence times of common ancestors depend heavily on good taxonomic coverage we have reanalyzed the genus Lolliguncula in light of new samples that increase the geographic and taxonomic coverage. New sequences were produced using standard methods to update an existing dataset for COI, 16S and Rhodopsin markers. Data was analyzed using various species delimitation methods, rigorous phylogenetic analyses and estimates of divergence times between clades. Within Lolliguncula we recover five monophyletic lineages that relate to the known species L. argus, L. diomedeae, L. panamensis, L. brevis North Atlantic and L. brevis South Atlantic. Except when using low divergence thresholds in ABGD, species delimitation methods only identify four of these lineages as distinct species, grouping L. argus and L. diomedeae as a single species. However, considering the reciprocal monophyly, recent divergence time estimate and morphological diagnoses we refrain from synonymizing L. argus within L. diomedeae, considering them very recently diverged species. The biogeography of the American loliginids is discussed, wherein basal cladogenesis in both Lolliguncula and Doryteuthis occur between the Atlantic and Pacific about 45 mya, with subsequent speciation around 20 mya associated with seafloor changes during the formation of the Caribbean. The recent speciation between L. argus and L. diomedeae is associated to oceanic environmental changes associated with glaciation, deep sea cooling and tropical upwelling.

Species specificity and intraspecific variation in the chemical profiles of Heliconius butterflies across a large geographic range.

In many animals, mate choice is important for the maintenance of reproductive isolation between species. Traits important for mate choice and behavioral isolation are predicted to be under strong stabilizing selection within species; however, such traits can also exhibit variation at the population level driven by neutral and adaptive evolutionary processes. Here, we describe patterns of divergence among androconial and genital chemical profiles at inter- and intraspecific levels in mimetic Heliconius butterflies. Most variation in chemical bouquets was found between species, but there were also quantitative differences at the population level. We found a strong correlation between interspecific chemical and genetic divergence, but this correlation varied in intraspecific comparisons. We identified "indicator" compounds characteristic of particular species that included compounds already known to elicit a behavioral response, suggesting an approach for identification of candidate compounds for future behavioral studies in novel systems. Overall, the strong signal of species identity suggests a role for these compounds in species recognition, but with additional potentially neutral variation at the population level.

Unexpected species diversity in electric eels with a description of the strongest living bioelectricity generator.

Is there only one electric eel species? For two and a half centuries since its description by Linnaeus, Electrophorus electricus has captivated humankind by its capacity to generate strong electric discharges. Despite the importance of Electrophorus in multiple fields of science, the possibility of additional species-level diversity in the genus, which could also reveal a hidden variety of substances and bioelectrogenic functions, has hitherto not been explored. Here, based on overwhelming patterns of genetic, morphological, and ecological data, we reject the hypothesis of a single species broadly distributed throughout Greater Amazonia. Our analyses readily identify three major lineages that diverged during the Miocene and Pliocene-two of which warrant recognition as new species. For one of the new species, we recorded a discharge of 860 V, well above 650 V previously cited for Electrophorus, making it the strongest living bioelectricity generator.

Karyoevolution of Crenicichla heckel 1840 (Cichlidae, Perciformes): a process mediated by inversions.

Crenicichla (Cichliformes, Cichlidae) present a highly conserved diploid number 2n=48 with fundamental numbers varying between 52 and 62. We analyzed four species in order to investigate the role of repetitive DNA in chromosome evolution in the genus. Crenicichla johanna, Crenicichla cf. saxatilis and Crenicichla cf. regani have 2n=48 (8 m/sm and 40st/a) and FN=56, while Crenicichla sp. 'Xingu I' has 2n=48 (48 st/a) and FN=48. Different patterns of constitutive heterochromatin distribution were observed including pericentric, interstitial and whole arm C bands. A single chromosome bears 18S rDNA clusters in most species, except C. johanna, where population variation exists in terms of the quantity and distribution of clusters and their association with interstitial telomeric sequences. All species showed hybridization of 5S rDNA sequences in an interstitial region on an acrocentric chromosome pair. The karyotypic differences and maintenance of the diploid number supports chromosome evolution mediated by inversions in Crenicichla The telomeric and 18S rDNA sequence association in various chromosomes of C. johanna are proposed to represent hotspots for breakage, favoring intra-chromosomal rearrangements. The results suggest that repetitive sequences can contribute to microstructural cytogenetic diversity in Crenicichla.

Surveying cephalopod diversity of the Amazon reef system using samples from red snapper stomachs and description of a new genus and species of octopus.

The cephalopod fauna of the southwestern Atlantic is especially poorly-known because sampling is mostly limited to commercial net-fishing operations that are relatively inefficient at obtaining cephalopods associated with complex benthic substrates. Cephalopods have been identified in the diets of many large marine species but, as few hard structures survive digestion in most cases, the identification of ingested specimens to species level is often impossible. Samples can be identified by molecular techniques like barcoding and for cephalopods, mitochondrial 16S and COI genes have proven to be useful diagnostic markers for this purpose. The Amazon River estuary and continental shelf are known to encompass a range of different substrates with recent mapping highlighting the existence of an extensive reef system, a type of habitat known to support cephalopod diversity. The present study identified samples of the cephalopod fauna of this region obtained from the stomachs of red snappers, Lutjanus purpureus, a large, commercially-important fish harvested by fisheries using traps and hook-and-line gear that are capable of sampling habitats inaccessible to nets. A total of 98 samples were identified using molecular tools, revealing the presence of three squid species and eight MOTUs within the Octopodidae, representing five major clades. These include four known genera, Macrotritopus, Octopus, Scaeurgus and Amphioctopus, and one basal group distinct from all known octopodid genera described here as Lepidoctopus joaquini Haimovici and Sales, new genus and species. Molecular analysis of large predatory fish stomach contents was found to be an incredibly effective extended sampling method for biodiversity surveys where direct sampling is very difficult.

Karyotypic Diversity and Evolution in a Sympatric Assemblage of Neotropical Electric Knifefish.

Chromosome changes can perform an important role in speciation by acting as post-zygotic reproductive barriers. The Neotropical electric fish genus Brachyhypopomus (Gymnotiformes, Hypopomidae) has 28 described species, but cytogenetic data are hitherto available only for four of them. To understand karyotype evolution and investigate the possible role of chromosome changes in the diversification of this genus, we describe here the karyotype of eight species of Brachyhypopomus from a sympatric assemblage in the central Amazon basin. We analyzed cytogenetic data in the context of a phylogenetic reconstruction of the genus and known patterns of geographical distribution. We found a strong phylogenetic signal for chromosome number and noted that sympatric species have exclusive karyotypes. Additional insights into the role of chromosome changes in the diversification of Brachyhypopomus are discussed.

The Karyotype of Microsternarchus aff. bilineatus: A First Case of Y Chromosome Degeneration in Gymnotiformes.

Various species and lineages that until recently were identified as Microsternarchus bilineatus (Hypopomidae, Gymnotiformes) have a widespread distribution in the Amazon and Orinoco River basins and across the Guiana shield. Recent molecular studies show five distinct lineages for Microsternarchus from different localities. These results suggest that this previously monotypic genus actually consists of more than one species. Here, we describe the karyotype of M. aff. bilineatus from the Cururutuia River (Bragança, Pará, Brazil). The diploid number of 48 chromosomes (14 meta-submetacentric/34 subtelo-acrocentric) is found for males and females, with an XX/XY sex chromosome system. The nucleolar organizer region is found in the short arm of pair 9. Constitutive heterochromatin occurs in the pericentromeric region of all chromosomes, in the distal region of 3p, 5p, 7p, 8q, 9q, 16q, and Xq, in the interstitial region in 2p, 10q, 11q, and 12q and all along 4p, and in a large block of the Y chromosome. These results indicate extensive karyotype divergence between this population and samples from Igarapé Tarumã Grande (Negro River, Amazonas, Brazil) studied by other researchers. Moreover, despite the diversity of sex chromosome systems found in Gymnotiformes, the XX/XY sex chromosome system of M. aff. bilineatus is the first case of Y chromosome degeneration in this order. The present data are valuable to help understand karyotype evolution in Hypopomidae.

Divergence of cryptic species of Doryteuthis plei Blainville, 1823 (Loliginidae, Cephalopoda) in the Western Atlantic Ocean is associated with the formation of the Caribbean Sea.

Although recent years have seen an increase in genetic analyses that identify new species of cephalopods and phylogeographic patterns, the loliginid squid of South America remain one of the least studied groups. The suggestion that Doryteuthis plei may represent distinct lineages within its extensive distribution along the western Atlantic coasts from Cape Hatteras, USA (36°N) to northern Argentina (35°S) is consistent with significant variation in a number of environmental variables along this range including in both temperature and salinity. In the present study D. plei samples were obtained from a large number of localities along the western Atlantic coasts to investigate the distribution of these possible species in a phylogeographic context. Phylogeographic analyses were performed using the mitochondrial Cytochrome Oxidase I gene and nuclear Rhodopsin gene. Divergence times were estimated using Bayesian strict clock dating with calibrations based on fossil records for divergence from the lineage containing Vampyroteuthis infernalis (162mya), the probable origins of the North American loliginids (45mya), and the European loliginids (20mya) and fossil statolith from Doryteuthis opalescens (3mya). Our results suggest a deep genetic divergence within Doryteuthis plei. The currently described specie consists of two genetically distinct clades (pair-wise genetic divergence of between 7.7 and 9.1%). One clade composed of individuals collected in northwestern Atlantic and Central Caribbean Atlantic waters and the other from southwestern Atlantic waters. The divergence time and sampling locations suggest the speciation process at approximately 16Mya, which is in full agreement with the middle Miocene orogeny of the Caribbean plate, ending up with the formation of the Lesser Antilles and the adjacent subduction zone, coinciding with a particularly low global sea level, resulting in the practical absence of continental shelves at the area, and therefore an effective geographic barrier for D. plei. Furthermore, this study also provides evidence of previously undocumented sub-population structuring in the Gulf of Mexico.

Integrated Cytogenetic and Mitochondrial DNA Analyses Indicate That Two Different Phenotypes of Hypancistrus (L066 and L333) Belong to the Same Species.

The diversity of Hypancistrus species in the Xingu River is remarkable and the variation in color morphs represents a real challenge to taxonomists to delimit species boundaries. One of the most recognizable Hypancistrus complexes is the worm-lined species, known in the aquarium trade as King Tiger Plec in English, Hypancistrus "pão" in Portuguese or under the L-numbers L066 and L333 that represent two melanic pigment pattern phenotypes. To assess the identity of these two phenotypes, we described their karyotypes and sequenced part of the mitochondrial cytochrome oxidase I gene (DNA barcode). These fishes have 52 chromosomes (40 meta-submetacentric and 12 subtelo-acrocentric) and a strong heteromorphism in chromosome pair 21 was observed, which does not correlate with the two phenotypes or sex. DNA barcodes separated the samples analyzed from Hypancistrus zebra and other publicly available sequences of Loricariidae showing no divergence between the two phenotypes. The data set indicates that worm-lined Hypancistrus from the Xingu form a single species with clear chromosomal and melanic pigment pattern polymorphisms.

Comparative Allometric Growth of the Mimetic Ephippid Reef Fishes Chaetodipterus faber and Platax orbicularis.

Mimesis is a relatively widespread phenomenon among reef fish, but the ontogenetic processes relevant for mimetic associations in fish are still poorly understood. In the present study, the allometric growth of two allopatric leaf-mimetic species of ephippid fishes, Chaetodipterus faber from the Atlantic and Platax orbicularis from the Indo-Pacific, was analyzed using ten morphological variables. The development of fins was considered owing to the importance of these structures for mimetic behaviors during early life stages. Despite the anatomical and behavioral similarities in both juvenile and adult stages, C. faber and P. orbicularis showed distinct patterns of growth. The overall shape of C. faber transforms from a rounded-shape in mimetic juveniles to a lengthened profile in adults, while in P. orbicularis, juveniles present an oblong profile including dorsal and anal fins, with relative fin size diminishing while the overall profile grows rounder in adults. Although the two species are closely-related, the present results suggest that growth patterns in C. faber and P. orbicularis are different, and are probably independent events in ephippids that have resulted from similar selective processes.

Karyotypic and morphological divergence between two cryptic species of Eigenmannia in the Amazon basin with a new occurrence of XX/XY sex chromosomes (Gymnotiformes: Sternopygidae)

Eigenmannia species are widely distributed in the Neotropics, with eight valid species currently recognized. Populations of Eigenmannia from three locations in the eastern Amazon were investigated using cytogenetic and morphological techniques, revealing two taxa designated here as Eigenmannia sp. "A" and Eigenmannia sp. "B". The species differ in three morphometric characters, two meristic characters, and one osteological character. Eigenmannia sp. "A" presents 2n = 34 (22 m/sm+12 st/a) and Eigenmannia sp. "B" presents 2n = 38 (14 m/sm+24st/a) and simple differentiated sex chromosomes of the type XX/XY. In both species the Constitutive Heterochromatin (CH) rich in A-T bases is distributed in the centromeric region of all chromosomes. Eigenmannia sp. "B" also presents CH blocks in the interstitial region of chromosome pairs 8, 9 and X which are positively stained with CMA3, indicating G-C rich regions. The NOR is located on the short arm of chromosome pair 17 of Eigenmannia sp. "A" and on the short arm of pair 14 of Eigenmannia sp. "B". FISH with rDNA probes hybridized to different-sized regions between homologs, suggesting heteromorphism. The differentiation of the X chromosome in Eigenmannia sp. "B" could be the result of amplification of repetitive DNA sequences.

Espécies de Eigenmannia estão amplamente distribuídas na região Neotropical, com oito espécies válidas atualmente reconhecidas. Populações de Eigenmannia de três localidades do leste da Amazônia foram investigadas usando técnicas citogenéticas e morfológicas, revelando dois táxons designados aqui como Eigenmannia sp. "A" e Eigenmannia sp. "B". As espécies diferem em três caracteres morfométricos, dois merísticos e um osteológico. Eigenmannia sp. "A" apresenta 2n = 34 (22 m/sm+12st/a) e Eigenmannia sp. "B" apresenta 2n = 38 (14 m/sm+24st/a) e cromossomos sexuais de diferenciação simples, do tipo XX/XY. Em ambas espécies a Heterocromatina Constitutiva (HC) rica em bases A-T está distribuída na região centromérica de todos os cromossomos. Eigenmannia sp. "B" também apresenta blocos de HC na região intersticial dos pares cromossômicos 8, 9 e X que coraram positivamente para CMA3, indicando regiões ricas em G-C. A NOR está localizada no braço curto do par 17 em Eigenmannia sp. "A" e no braço curto do par 14 em Eigenmannia sp. "B". FISH com sondas de rDNA hibridizaram em regiões de tamanhos diferentes entre os homólogos, sugerindo heteromorfismo. A diferenciação do cromossomo X em Eigenmannia sp. "B" pode ser o resultado de amplificação de sequências repetitivas de DNA.

Chromosomal Variability Between Populations of Electrophorus electricus Gill, 1864 (Pisces: Gymnotiformes: Gymnotidae).

The electric eel, Electrophorus electricus, the only species of its genus, has a wide distribution in the Amazon and Orinoco drainages. There is little previous information regarding the population variation in E. electricus, with only basic karyotype data from two populations (Amazon and Araguaia Rivers). Karyotypic description and analysis of CO1 barcode sequences were performed for E. electricus from three localities (Caripetuba, Irituia, and Maicuru Rivers). All samples share the 2n=52 (42 m-sm [meta-submetacentric] +10 st-a [subtelo-acrocentric]) with previously studied material. However, the Maicuru River samples differ from the other populations, as they have B chromosomes. The distribution of noncentromeric constitutive heterochromatin between samples is relatively divergent. All samples analyzed present the Nucleolar Organizer Region (NOR) located in a single chromosome pair. In the samples from Caripetuba, NORs were colocalized with a heterochromatin block, whereas the NOR was flanked by heterochromatin in Maicuru River samples and pericentromeric heterochromatin adjacent NOR was found in Irituia River samples. Alignment of CO1 barcode sequences indicated no significant differentiation between the samples analyzed. Results suggest that karyotypic differences between samples from the Caripetuba, Irituia, and Amazon Rivers represent chromosome polymorphisms. However, differences between the samples from the Maicuru and Araguaia Rivers and the remaining populations could represent interpopulation differentiation, which has not had time to accrue divergence at the CO1 gene level.

Molecular phylogeny of the genus Lolliguncula steenstrup, 1881 based on nuclear and mitochondrial DNA sequences indicates genetic isolation of populations from north and South atlantic, and the possible presence of further cryptic species.

Squid of the genus Lolliguncula Steenstrup, 1881 are small bodied, coastal species capable of tolerating low salinity. Lolliguncula sp. are found exclusively in the New World, although only one of the four recognized species (Lolliguncula brevis) occurs in the Atlantic Ocean. Preliminary morphological analyses suggest that Lolliguncula brevis populations in the North and South Atlantic may represent distinct species. The principal objective of the present study was to verify the phylogenetic relationships within the genus and test for the presence of possible cryptic species. Both gene and species tree topologies indicated that Lolliguncula brevis specimens from the North and South Atlantic represent distinct phylogenetic clades. In contrast with previous studies, L. panamensis was identified as the basal species of the genus. Our results provide important insights into the phylogenetic relationships among the Lolliguncula specimens analyzed, and confirm the genetic separation of Lolliguncula brevis populations of the North and South Atlantic at the level of sister species.

New molecular phylogeny of the squids of the family Loliginidae with emphasis on the genus Doryteuthis Naef, 1912: mitochondrial and nuclear sequences indicate the presence of cryptic species in the southern Atlantic Ocean.

The family Loliginidae Lesueur, 1821, is currently considered to include seven genera and approximately 50 species of neritic and coastal squids. These commercially important species occur in tropical and temperate coastal waters around the world. The taxonomy of the family has been revised a number of times in recent years, focusing in particular on genera such as Doryteuthis, Sepioteuthis, Alloteuthis, and Uroteuthis, which are represented by populations in the New World, Oceania, Europe/Africa, and Asia. However, no detailed phylogenetic analysis is available for the loliginids of the southern Atlantic, in particular the genus Doryteuthis. The present molecular study analyzed 81 loliginid taxa from around the world. The partial sequencing of the mitochondrial 16S and Cytochrome Oxidase I genes, and the nuclear rhodopsin gene revealed a number of important patterns, recovering the monophyletic status of the majority of the genera and revealing possible cryptic species in Doryteuthis plei D. pealei, Uroteuthis duvauceli and Sepioteuthis lessoniana.