Independent Colonization Research Articles

Rapid Parallel Adaptation to Anthropogenic Heavy Metal Pollution.

The impact of human-mediated environmental change on the evolutionary trajectories of wild organisms is poorly understood. In particular, capacity of species to adapt rapidly (in hundreds of generations or less), reproducibly and predictably to extreme environmental change is unclear. Silene uniflora is predominantly a coastal species, but it has also colonized isolated, disused mines with phytotoxic, zinc-contaminated soils. To test whether rapid, parallel adaptation to anthropogenic pollution has taken place, we used reduced representation sequencing (ddRAD) to reconstruct the evolutionary history of geographically proximate mine and coastal population pairs and found largely independent colonization of mines from different coastal sites. Furthermore, our results show that parallel evolution of zinc tolerance has occurred without gene flow spreading adaptive alleles between mine populations. In genomic regions where signatures of selection were detected across multiple mine-coast pairs, we identified genes with functions linked to physiological differences between the putative ecotypes, although genetic differentiation at specific loci is only partially shared between mine populations. Our results are consistent with a complex, polygenic genetic architecture underpinning rapid adaptation. This shows that even under a scenario of strong selection and rapid adaptation, evolutionary responses to human activities (and other environmental challenges) may be idiosyncratic at the genetic level and, therefore, difficult to predict from genomic data.

Awards of JSE Outstanding Papers (2019)

Awards of JSE Outstanding Papers (2019)

Two species of slow worm (Anguis fragilis, A. colchica) present in the Baltic region

Abstract Five European slow worms (Anguis) have mostly parapatric distributions. Two species, A. fragilis and A. colchica, are widely distributed across the western and eastern parts of the genus range. Their contact zone runs from the north-eastern Balkans, through Pannonia to northern Central Europe. In northern Poland, the contact zone has been located approximately between the North and East European Plains. Here, we present the first mitochondrial and nuclear DNA data from Finland and the coastal Baltics. We demonstrate that A. fragilis enters the East European Plains, where it is presumably distributed along the Baltic coast. Our data indicate that A. colchica is present more inland and to the north of Riga. The genetic structure suggests three independent postglacial colonization events in the Baltics (two by A. colchica). The presence of the two species, A. fragilis and A. colchica, should be considered by the conservation legislations of Lithuania, Latvia and Russia.

New occurrence records of Lepidodactylus lugubris (Duméril & Bibron, 1836) (Squamata: Gekkonidae) for the amazon and atlantic forest in Brazil

The gecko Lepidodactylus lugubris is native to southwest Pacific but is widely introduced into the neotropics. In Brazil, its known distribution was limited to the city of Belem in the Amazon. This work presents three new records of the species for the states of Para and Bahia. Records from Para were made in Capitao Poco and in Marajo island, while the third one was in Salvador, Bahia. We believe these records represent independent colonizations, with specimens arriving in Capitao Poco in auto-vehicles coming from Belem, while colonizations of Salvador and Breves may have occurred by ships. Introductions of L. lugubris were described as accidental or due to pet trade, so the latter alternative cannot be discarded. It seems likely that L. lugubris has already spread to other states and biomes across the north and northeast of Brazil, but its occurrence is yet to be documented in these regions.

Patterns of genetic divergence and demographic history shed light on island-mainland population dynamics and melanic plumage evolution in the white-winged Fairywren.

The existence of distinct traits in island versus mainland populations offers opportunities to gain insights into how eco-evolutionary processes operate under natural conditions. We used two island colonization events in the white-winged fairywren (Malurus leucopterus) to investigate the genomic and demographic origin of melanic plumage. This avian species is distributed across most of Australia, and males of the mainland subspecies (M. l. leuconotus) exhibit a blue nuptial plumage in contrast to males of two island subspecies - M. l. leucopterus on Dirk Hartog Island and M. l. edouardi on Barrow Island - that exhibit a black nuptial plumage. We used reduced-representation sequencing to explore differentiation and demographic history in this species and found clear patterns of divergence between mainland and island populations, with additional substructuring on the mainland. Divergence between the mainland and Dirk Hartog was approximately 10 times more recent than the split between the mainland and Barrow Island, supporting two independent colonizations. In both cases, estimated gene flow between the mainland and the islands was low, contributing to signals of divergence among subspecies. Our results present demographic reconstructions of mainland-island dynamics and associated plumage variation in white-winged fairywrens, with broader implications regarding our understanding of convergent evolution in insular populations.

Review of the hagfishes (Myxinidae) from the Galapagos Islands, with descriptions of four new species and their phylogenetic relationships

AbstractHagfishes are an ancient group of benthic marine craniates that are found in deep or cold waters around the world. Among the 83 valid species, four are described from the Galapagos Islands: Eptatretus bobwisneri, E. grouseri, E. mccoskeri and Rubicundus lakeside. During a recent expedition to the archipelago, six species of hagfishes were collected, including four undescribed species of the genera Eptatretus (Eptatretus goslinei sp. nov.) and Myxine (Myxine greggi sp. nov., M. martinii sp. nov. and M. phantasma sp. nov.). In this paper, we provide a review of the eight species of hagfishes from the Galapagos Islands, including new diagnoses and an identification key for all species. Myxine phantasma is remarkable in that it is the only species of Myxine known to completely lack melanin-based pigments. Our species delineations were based on both morphological and molecular analyses. A phylogenetic hypothesis based on molecular data suggests that Galapagos hagfishes arose from multiple independent colonisations of the islands from as many as five different ancestral lineages. The large number of endemic hagfishes in the geologically young Galapagos Islands suggests that there is much global hagfish diversity yet to be discovered.

A unifying, eco‐physiological framework for animal dormancy

AbstractVarious animals across the tree of life express some form of programmed dormancy (e.g. hibernation, diapause) to maximize fitness in highly seasonal environments. The integrated phenotype of animals undergoing programmed dormancy is strikingly similar among diverse groups; however, research on programmed dormancy has historically been phylogenetically siloed. A broad comparative approach could clarify new angles for answering fundamental questions about programmed dormancy evolution.To advance this approach, we present a cross‐taxonomic framework describing dimensions that distinguish animal dormancies and provide a set of core traits that animals regulate as they progress through the eco‐physiological phases of deep, programmed dormancy.We use this universal framework to explore the ultimate drivers and evolutionary consequences of dormancy across the tree of life. Deep, programmed dormancy appears to be a predictable and repeated adaptation to highly seasonal environments that draws on a conserved suite of ancestral traits. We highlight evidence for molecular convergence in signalling pathways coordinating environmental sensing and energy metabolism in the insect and mammal lineages, separated by 700 million years of evolution and representing independent colonizations of highly seasonal environments.Lastly, we discuss the utility of this new framework and highlight opportunities and challenges for researchers to continue advancing our understanding of dormancy through a broad, comparative lens.A freePlain Language Summarycan be found within the Supporting Information of this article.

First freshwater mussel-associated piscicolid leech from East Asia

Parasites and symbionts of freshwater mussels are poorly understood, although a diverse assemblage of mussel-associated leeches (Glossiphoniidae) was recently described. Here, we report on the discovery of a fish leech (Piscicolidae) in the mantle cavity of the freshwater mussel Cristaria plicata (Unionidae) in the Russian Far East. It is the first member of this leech family being associated with freshwater molluscs. This leech does not match any known genus and species both morphologically and genetically, and is described here as Alexandrobdella makhrovigen. & sp. nov. It uses mussels as shelter (and probably as a secondary host), while the Amur catfish Silurus asotus (Siluridae) seems to be the primary host. These novel findings indicate that mussel-associated leech assemblage contains at least one piscicolid species. Our fossil-calibrated phylogeny suggests that the crown group of Piscicolidae was originated in the Early Cretaceous. This primarily marine family shares at least five independent colonization events into freshwater environments.

Genetic diversity and phylogeography of Corynosoma australe Johnston, 1937 (Acanthocephala: Polymorphidae), an endoparasite of otariids from the Americas in the northern and southern hemispheres.

Adult specimens of Corynosoma australe Johnston, 1937 were recorded from the intestines of California sea lions, Zalophus californianus (Lesson), from Baja California Peninsula, Mexico, whereas larval forms were collected from two fish species on the Argentinian coast. Adult specimens of C. australe were morphologically characterized by having a cylindrical proboscis with 18-20 rows of 12-14 hooks per row and a cylindrical trunk expanded anteriorly into a disk with tiny, triangular spines spreading almost to three quarters of the hind-trunk in males and to the posterior body end in females. The aim of this study was to explore the genetic diversity and systematic position of C. australe distributed in the Americas. Newly generated sequences of the mitochondrial cytochrome c oxidase subunit 1 (cox 1) gene were compared with sequences available from GenBank. Phylogenetic analyses performed with the cox 1 dataset using maximum likelihood and Bayesian inference showed that the 11 new sequences of C. australe recovered from the California sea lion in northern Mexico plus the six sequences from Argentinian seashores formed a clade with other sequences of specimens previously identified as C. australe. The intraspecific genetic divergence among the isolates was very low, ranging from 1 to 1.7%, and in combination with the phylogenetic trees confirmed that the isolates belonged to the same species. The cox 1 haplotype network inferred with 27 sequences revealed 18 haplotypes divided into two clusters clearly separated from each other by 5 substitutions. The first cluster corresponded to specimens from the Northern Hemisphere (United States of America and Mexico), and the second corresponded to specimens from the Southern Hemisphere (Argentina and Brazil). The current evidence suggests that C. australe has an amphitemperate distribution and is associated mainly with otariids with secondary and independent colonization events to other mammals and the Magellanic penguin in the Southern Hemisphere.

Molecular phylogenetics of Lotus (Leguminosae) with emphasis in the tempo and patterns of colonization in the Macaronesian region

With a wide distribution range including Europe and Asia, Lotus (Leguminosae) represents the largest genus within Loteae. It is particularly diverse in the Mediterreanean region and in the five archipelagos of Macaronesia (Atlantic Ocean). However, little is known about the relationships among the 14 sections currently recognized within Lotus and about the timing and patterns of its colonization in the Macaronesian region. In this investigation, we use four DNA regions (nuclear ribosomal ITS plus three plastid regions) in the most comprehensive sampling of Lotus species to date (some endemic species within the Canary Islands were poorly represented in previous phylogenetic analyses) to infer relationships within this genus and to establish patterns of colonization in Macaronesia. Divergence time estimates and habitat reconstruction analyses indicate that Lotus likely diverged about 7.86 Ma from its sister group, but all colonization events to Macaronesia occurred more recently (ranging from the last 0.23 to 2.70 Ma). The diversification of Lotus in Macaronesia involved between four and six independent colonization events from four sections currently distributed in Africa and Europe. A major aspect shaping the current distribution of taxa involved intra-island colonization of mainly new habitats and inter-island colonization of mostly similar habitats, with Gran Canaria and Tenerife as the major sources of diversification and of further colonization events. Section Pedrosia is the most diverse in terms of colonization events, number of species, and habitat heterogeneity, including a back-colonization event to the continent. Subsections within Pedrosia radiated into diverse habitat types recently (late Pleistocene, ca 0.23–0.29 Ma) and additional molecular markers and sampling would be necessary to understand the most recent dispersal events of this group within the Canary Islands and Cape Verde.

A Disjunctive Marginal Edge of Evergreen Broad-Leaved Oak (Quercus gilva) in East Asia: The High Genetic Distinctiveness and Unusual Diversity of Jeju Island Populations and Insight into a Massive, Independent Postglacial Colonization.

Jeju Island is located at a marginal edge of the distributional range of East Asian evergreen broad-leaved forests. The low genetic diversity of such edge populations is predicted to have resulted from genetic drift and reduced gene flow when compared to core populations. To test this hypothesis, we examined the levels of genetic diversity of marginal-edge populations of Quercus gilva, restricted to a few habitats on Jeju Island, and compared them with the southern Kyushu populations. We also evaluated their evolutionary potential and conservation value. The genetic diversity and structure were analyzed using 40 polymorphic microsatellite markers developed in this study. Ecological Niche Modeling (ENM) has been employed to develop our insights, which can be inferred from historical distribution changes. Contrary to our expectations, we detected a similar level of genetic diversity in the Jeju populations, comparable to that of the southern Kyushu populations, which have been regarded as long-term glacial refugia with a high genetic variability of East Asian evergreen trees. We found no signatures of recent bottlenecks in the Jeju populations. The results of STRUCTURE, neighbor-joining phylogeny, and Principal Coordinate Analysis (PCoA) with a significant barrier clearly demonstrated that the Jeju and Kyushu regions are genetically distinct. However, ENM showed that the probability value for the distribution of the trees on Jeju Island during the Last Glacial Maximum (LGM) converge was zero. In consideration of these results, we hypothesize that independent massive postglacial colonization from a separate large genetic source, other than Kyushu, could have led to the current genetic diversity of Jeju Island. Therefore, we suggest that the Jeju populations deserve to be separately managed and designated as a level of management unit (MU). These findings improve our understanding of the paleovegetation of East Asian evergreen forests, and the microevolution of oaks.

"Into and Out of" the Qinghai-Tibet Plateau and the Himalayas: Centers of origin and diversification across five clades of Eurasian montane and alpine passerine birds.

Encompassing some of the major hotspots of biodiversity on Earth, large mountain systems have long held the attention of evolutionary biologists. The region of the Qinghai‐Tibet Plateau (QTP) is considered a biogeographic source for multiple colonization events into adjacent areas including the northern Palearctic. The faunal exchange between the QTP and adjacent regions could thus represent a one‐way street (“out of” the QTP). However, immigration into the QTP region has so far received only little attention, despite its potential to shape faunal and floral communities of the QTP. In this study, we investigated centers of origin and dispersal routes between the QTP, its forested margins and adjacent regions for five clades of alpine and montane birds of the passerine superfamily Passeroidea. We performed an ancestral area reconstruction using BioGeoBEARS and inferred a time‐calibrated backbone phylogeny for 279 taxa of Passeroidea. The oldest endemic species of the QTP was dated to the early Miocene (ca. 20 Ma). Several additional QTP endemics evolved in the mid to late Miocene (12–7 Ma). The inferred centers of origin and diversification for some of our target clades matched the “out of Tibet hypothesis’ or the “out of Himalayas hypothesis” for others they matched the “into Tibet hypothesis.” Three radiations included multiple independent Pleistocene colonization events to regions as distant as the Western Palearctic and the Nearctic. We conclude that faunal exchange between the QTP and adjacent regions was bidirectional through time, and the QTP region has thus harbored both centers of diversification and centers of immigration.

Cave-adapted evolution in the North American amblyopsid fishes inferred using phylogenomics and geometric morphometrics.

Cave adaptation has evolved repeatedly across the Tree of Life, famously leading to pigmentation and eye degeneration and loss, yet its macroevolutionary implications remain poorly understood. We use the North American amblyopsid fishes, a family spanning a wide degree of cave adaptation, to examine the impact of cave specialization on the modes and tempo of evolution. We reconstruct evolutionary relationships using ultraconserved element loci, estimate the ancestral histories of eye-state, and examine the impact of cave adaptation on body shape evolution. Our phylogenomic analyses provide a well-supported hypothesis for amblyopsid evolutionary relationships. The obligate blind cavefishes form a clade and the cave-facultative eyed spring cavefishes are nested within the obligate cavefishes. Using ancestral state reconstruction, we find support for at least two independent subterranean colonization events within the Amblyopsidae. Eyed and blind fishes have different body shapes, but not different rates of body shape evolution. North American amblyopsids highlight the complex nature of cave-adaptive evolution and the necessity to include multiple lines of evidence to uncover the underlying processes involved in the loss of complex traits.

Accumulation of Deleterious Mutations in Landlocked Threespine Stickleback Populations.

Colonization of new habitats often reduces population sizes and may result in the accumulation of deleterious mutations by genetic drift. Compared with the genomic basis for adaptation to new environments, genome-wide analysis of deleterious mutations in isolated populations remains limited. In the present study, we investigated the accumulation of deleterious mutations in five endangered freshwater populations of threespine stickleback (Gasterosteus aculeatus) in the central part of the mainland of Japan. Using whole-genome resequencing data, we first conducted phylogenomic analysis and confirmed at least two independent freshwater colonization events in the central mainland from ancestral marine ecotypes. Next, analyses of single nucleotide polymorphisms showed a substantial reduction of heterozygosity in freshwater populations compared with marine populations. Reduction in heterozygosity was more apparent at the center of each chromosome than the peripheries and on X chromosomes compared with autosomes. Third, bioinformatic analysis of deleterious mutations showed increased accumulation of putatively deleterious mutations in the landlocked freshwater populations compared with marine populations. For the majority of populations examined, the frequencies of putatively deleterious mutations were higher on X chromosomes than on autosomes. The interpopulation comparison indicated that the majority of putatively deleterious mutations may have accumulated independently. Thus, whole-genome resequencing of endangered populations can help to estimate the accumulation of deleterious mutations and inform us of which populations are the most severely endangered. Furthermore, analysis of variation among chromosomes can give insights into whether any particular chromosomes are likely to accumulate deleterious mutations.

Community Structure and Undescribed Species Diversity in Non-Pollinating Fig Wasps Associated with the Strangler Fig Ficus petiolaris

Abstract Figs and their associated mutualistic and parasitic wasps have been a focus of intensive ecological and evolutionary research due to their diversity, unusual reproductive biology, and highly coevolved interspecific relationships. Due to the ecological dependence of their interactions, fig wasps were once considered to be fig-species specific and to cospeciate with their hosts, however, a growing body of evidence reveals mixed support for species specificity and the importance of additional evolutionary processes (e.g., host switching) structuring these long-term interactions. Our research on the genus Idarnes Walker, 1843 (Hymenoptera, Agaonidae), a common non-pollinating wasp of New World fig flowers, reveals a community in which multiple wasp species coexist on the same host in space and time. Using both molecular and morphological data, we identify five distinct Idarnes lineages associated with a single host fig species, Ficus petiolaris Kunth, 1817 (Rosales, Moraceae). A comprehensive phylogenetic analysis including Idarnes species from numerous host fig species reveals that the lineages associated with F. petiolaris do not form a monophyletic group but are distantly related, suggesting multiple independent colonization events and subsequent diversification. Morphological and ecological data provide support that the wasps are partitioning niches within the figs, explaining the coexistence of these diverse lineages on the same host fig. These results, coupled with a growing body of research on pollinating and non-pollinating fig wasps, bring into focus a more dynamic picture of fig and fig wasp coevolution and highlight how wasp lineage divergence and niche partitioning contributes to increased species diversity and community structure on a single fig host.

A glide over the Indo-Australian geological maze: repeated transgressions of Lydekker’s and Wallace’s Lines in archdukes, barons and dukes (Nymphalidae: Limenitidinae: Adoliadini)

Abstract Archdukes, barons, counts, dukes and marquises are forest-dwelling butterflies found in mainland Asia and most islands of the Indo-Australian archipelago west of Wallace’s Line, with only a few species occurring as far east as the Bismarck Archipelago. This pattern is unusual among butterfly groups of the region, which often present more widespread geographical ranges bearing little signature of Lydekker’s and Wallace’s Lines. Using a molecular multimarker matrix, we infer the first dated phylogeny for this clade and estimate its biogeographical history. We recover the Oriental genus Euthalia as polyphyletic, although other genera are monophyletic. The clade originated in continental Indomalaya in the late Oligocene ~24 Mya, when the Indo-Australian archipelago was at one of the most dynamic stages of its orogeny. Multiple independent colonization events towards the Lesser Sunda Islands, Moluccas, Australia and New Guinea suggest the relative permeability of Lydekker’s and Wallace’s Lines to these butterflies. Colonization of Melanesia took place twice, probably before the recent formation of Sulawesi. The study of Indo-Australian Adoliadini provides additional evidence that biogeographical barriers long thought to prevent exchange between the Asian and Australian biotas are, in fact, permeable especially to vagile insect lineages in the region.

Phenotypic divergence among threespine stickleback that differ in nuptial coloration.

By studying systems in their earliest stages of differentiation, we can learn about the evolutionary forces acting within and among populations and how those forces could contribute to reproductive isolation. Such an understanding would help us to better discern and predict how selection leads to the maintenance of multiple morphs within a species, rather than speciation. The postglacial adaptive radiation of the threespine stickleback (Gasterosteus aculeatus) is one of the best‐studied cases of evolutionary diversification and rapid, repeated speciation. Following deglaciation, marine stickleback have continually invaded freshwater habitats across the northern hemisphere and established resident populations that diverged innumerable times from their oceanic ancestors. Independent freshwater colonization events have yielded broadly parallel patterns of morphological differences in freshwater and marine stickleback. However, there is also much phenotypic diversity within and among freshwater populations. We studied a lesser‐known freshwater “species pair” found in southwest Washington, where male stickleback in numerous locations have lost the ancestral red sexual signal and instead develop black nuptial coloration. We measured phenotypic variation in a suite of traits across sites where red and black stickleback do not overlap in distribution and at one site where they historically co‐occurred. We found substantial phenotypic divergence between red and black morphs in noncolor traits including shape and lateral plating, and additionally find evidence that supports the hypothesis of sensory drive as the mechanism responsible for the evolutionary switch in color from red to black. A newly described third “mixed” morph in Connor Creek, Washington, differs in head shape and size from the red and black morphs, and we suggest that their characteristics are most consistent with hybridization between anadromous and freshwater stickleback. These results lay the foundation for future investigation of the underlying genetic basis of this phenotypic divergence as well as the evolutionary processes that may drive, maintain, or limit divergence among morphs.

Pinworms of the red howler monkey (Alouatta seniculus) in Colombia: Gathering the pieces of the pinworm-primate puzzle.

Pinworms of primates are believed to be highly host specific parasites, forming co-evolutionary associations with their hosts. In order to assess the strength and reach of such evolutionary links, we need to have a broad understanding of the pinworm diversity associated with primates. Here, we employed an integrative taxonomic approach to assess pinworm diversity in red howler monkeys in Colombia. Molecular and morphological evidence validate the presence of at least four different species of Trypanoxyuris occurring in red howler monkeys: T. minutus, a widely distributed species, and three new species, T. seunimiii n. sp., T. kemuimae n. sp. and T. kotudoi n. sp. The mitochondrial COI gene and the 28S ribosomal gene were used for phylogenetic assessments through Bayesian inference. The three new species were morphologically distinct and formed reciprocally monophyletic lineages. Further molecular lineage subdivision in T. minutus and T. kotudoi n. sp. without morphological correspondence, suggests the potential scenario for the existence of cryptic species. Phylogenetic relationships imply that the different species of Trypanoxyuris occurring in each howler monkey species were acquired through independent colonization events. On-going efforts to uncover pinworm diversity will allow us to test the degree of host specificity and the co-phylogenetic hypothesis, as well as to further unravel the primate-pinworm evolutionary history puzzle.

The lichenized genus Cora (Basidiomycota: Hygrophoraceae) in Mexico: high species richness, multiple colonization events, and high endemism

AbstractIn a continued effort to catalog the numerous phylogenetically detected and predicted species of Cora in the Americas, we focus here on the diversity of the genus in Mexico and the phylogenetic relationships of the taxa present in this area. Based on previous results and new collections, 12 taxa are recognized in Mexico, including eight new species and one new subspecies. The 12 taxa form 11 unrelated lineages within the genus, indicating multiple independent colonization from Central and South America. While the new subspecies is nested within a species known from the northern Andes in South America, the other species are all putative endemics for Mexico, resulting in endemism of 92% at species level and 100% at taxon level. Considering the rather narrow area of origin of the sequenced specimens in southeastern Mexico and the previously documented range of Cora including the northwestern part of the country, plus the underlying topography, we predict that the 12 species and subspecies now known represent only about 20% of the total richness of Cora in the country, and that many more endemic lineages are to be found in the western and northwestern parts (Sierra Madre Occidental). The new taxa from Mexico formally introduced in this study are Cora benitoana sp. nov., with a strongly projecting, cyphelloid hymenophore; C. buapana sp. nov., with elongate, finger-like and partly branched appendages on the lower medullary hyphae; C. dewisanti subsp. mexicana subsp. nov., with a marginally protruding hymenophore; C. guzmaniana sp. nov., with a partly setose lobe surface; C. ixtlanensis sp. nov., a phenotypically cryptic species similar but unrelated to C. terrestris; C. lawreyana sp. nov., with globose hyphal appendages; C. marusae sp. nov., a phenotypically cryptic species similar but unrelated to C. comaltepeca; C. totonacorum sp. nov., a phenotypically cryptic species similar but phylogenetically distant to C. davidia; and C. zapotecorum sp. nov., with a very thinly pilose lobe surface.

The oldest freshwater crabs: claws on dinosaur bones

With approximately 1,500 extant species, freshwater crabs (Decapoda: Brachyura) are among the most diverse decapod crustaceans. Nevertheless, their fossil record is extremely limited: only Potamidae, Potamonautidae and Trichodactylidae are reported up to the Eocene of the Neotropics so far. This work documents unusually large decapod claws from the Upper Cretaceous (Campanian) continental deposits of Velaux and vicinity (southern France), in close association with large vertebrate remains. In addition to (1) the systematic assignment of these claws, the study addresses (2) the salinity trends in the deposit environment from its faunal assemblage and the elementary chemical patterns of fossils, and (3) the likely scenario for their auto/allochthony in the Velaux fluvial system. These claws belong to a new taxon, Dinocarcinus velauciensis n. gen. n. sp., referred to as Portunoidea sensu lato, a group of “true” crabs nowadays linked to marine systems. However, the faunal assemblage, the claw taphonomy and the carbonates Y/Ho signatures support their ancient freshwater/terrestrial ecology, making them the oldest reported continental brachyurans and extending the presence of crabs in freshwater environments by 40 Ma. Either as primary or as secondary freshwater crabs, the occurrence of these portunoids in Velaux is an evidence for the independent colonizations of continental environments by multiple brachyuran clades over time, as early as the Campanian.