Case Of Sympatry Research Articles

Phylogenomics and species delimitation of an abundant and little-studied Amazonian forest spiny rat

Species delimitation studies based on integrating different datasets such as genomic, morphometric, and cytogenetics data are rare in studies focused on Neotropical rodents. As a consequence, the evolutionary history of most of these genera remains poorly understood. Proechimys is a highly diverse and widely distributed genus of Neotropical spiny rats with unique traits like multiple sympatry, micro-habitat segregation, and fuzzy species limits. Here, we applied RAD-Seq to infer the phylogenetic relationships, estimate the species boundaries, and estimate the divergence times for Proechimys, one of the most common and least studied small mammals in the Amazon. We tested whether inferred lineages in the phylogenetic trees could be considered distinct species based on the genomic dataset and morphometric data. Analyses revealed the genus is not monophyletic, with Proechimys hoplomyoides sister to a group of Hoplomys gymnurus + all other Proechimys species, contesting the generic status of Hoplomys. There are five main clades in Proechimys stricto sensu (excluding H. gymnurus and P. hoplomyoides). Species delimitation analyses supported 25 species within the genus Proechimys. The five main clades in Proechimys stricto sensu also showed similar ages for their origins, and two rapid diversification events were identified in the Early Pliocene and in the Early Pleistocene. Most cases of sympatry in Proechimys occur among species from the different main clades, and although Proechimys is an inhabitant of the Amazon, three species occupied the Cerrado biome during the Pleistocene. We could associate available nominal taxon, cytogenetics information, and DNA sequences in Genbank to most of the 25 species we hypothesized from our delimitation analyses. Based on our analyses, we estimate that eight forms represent putative new species that need a taxonomic revision.

Phylogeographical analysis of character displacement in feeding phenotypes of snail-feedingAcoptolabrusground beetles

AbstractEcological character displacement predicts that interspecific resource competition results in greater trait divergence between species in sympatry than in allopatry. However, other processes, such as ecological sorting, result in the same pattern of trait variation. In this study, we characterize character displacement in eight species of snail-feeding Acoptolabrus ground beetles in the Far East. Acoptolabrus exhibit divergent feeding phenotypes, including species with a slender forebody that is able to intrude into large shells and species with stout heads and mandibles for crushing small shells. The pattern of character displacement in feeding phenotypes was confirmed by multivariate analysis of body dimensions. Molecular phylogenetic analysis, divergence time estimation and biogeographical analysis revealed that sympatry and phenotypic divergence occurred repeatedly during the Pleistocene and almost simultaneously within each geographical area. Comparative analysis revealed that the evolution of feeding phenotypes best fitted a selective model with three adaptive optima, corresponding to the three cases of sympatry with a congener. Repeated coincidences of sympatry and adaptive differentiation in feeding phenotypes suggested causal relationships, although the precise order of events was difficult to discriminate. This study provides insight into the spatiotemporal dynamics of interspecific interactions and adaptive phenotypic diversification.

Cryptic diversity and ancient diversification in the northern Atlantic Forest Pristimantis (Amphibia, Anura, Craugastoridae)

The Neotropical region is known both for its megadiverse fauna and for the significant deficiency of our knowledge on species limits. The Amazon and Atlantic Forest are the two most diverse and large rainforests in South America, and they harbor many groups of sister species and sister genera. The frog genus Pristimantis is the most speciose genus of terrestrial vertebrates with 546 species, but only three of them occur in the Atlantic forest. Herein, we investigate the diversification history and phylogenetic relationship among the Atlantic Forest Pristimantis lineages in a spatial-temporal framework, using mitochondrial and nuclear genes. Our results reveal a remarkable hidden diversity, with nine highly structure lineages that may correspond to undescribed species, with many cases of sympatry among these divergent lineages. Atlantic forest Pristimantis form a monophyletic group that started to diversify over 40 million years ago. This ancient group shows diversification events that remount the early bursts of the Atlantic Forest diversification history, as well as lineage diversification likely resulting from recent Pleistocene climatic fluctuations. Future work must concentrate in comparing these lineages under an integrative framework including morphology, advertisement calls and other ecology traits to confidently delimit species of Pristimantis in the Atlantic Forest.

Are we underestimating the occurrence of sympatric populations?

Sympatric populations are conspecific populations that coexist spatially. They are of interest in evolutionary biology by representing the potential first steps of sympatric speciation and are important to identify and monitor in conservation management. Reviewing the literature pertaining to sympatric populations, we find that most cases of sympatry appear coupled to phenotypic divergence, implying ease of detection. In comparison, phenotypically cryptic, sympatric populations seem rarely documented. We explore the statistical power for detecting population mixtures from genetic marker data, using commonly applied tests for heterozygote deficiency (i.e., Wahlund effect) and the structure software, through computer simulations. We find that both tests are efficient at detecting population mixture only when genetic differentiation is high, sample size and number of genetic markers are reasonable and the sympatric populations happen to occur in similar proportions in the sample. We present an approximate expression based on these experimental factors for the lower limit of FST , beyond which power for structure collapses and only the heterozygote-deficiency tests retain some, although low, power. The findings suggest that cases of cryptic sympatry may have passed unnoticed in population genetic screenings using number of loci typical of the pre-genomics era. Hence, cryptic sympatric populations may be more common than hitherto thought, and we urge more attention being diverted to their detection and characterization.

Influences of oceanic islands and the Pleistocene on the biogeography and evolution of two groups of Australasian parrots (Aves: Psittaciformes: Eclectus roratus, Trichoglossus haematodus complex). Rapid evolution and implications for taxonomy and conservation

AbstractThe Australasian region is a centre of biodiversity and endemism, mainly based on the tropical climate in combination with the large amount of islands. During the Pleistocene, islands of the Sahul Shelf (Australia, New Guinea, Aru Islands) had been part of the same land mass, while islands within the Wallacea (Lesser Sunda Islands, Moluccas, Sulawesi etc.) remained isolated. We investigated biogeographical avian diversification patterns of two species complexes across the Wallacea and the Sahul Shelf: the Eclectus Parrot Eclectus roratus Wagler, 1832, and the Rainbow Lorikeet Trichoglossus haematodus Linnaeus, 1771. Both species are represented by a large number of described geographical subspecies. We used mitochondrial cytochrome b (cyt b) sequences for phylogenetic and network analysis to detect biogeographic roles of islands and avian diversification patterns. The number of threatened taxa in this region is increasing rapidly and there is an urgent need for (sub-)species conservation in this region. Our study provides first genetic evidence for treating several island taxa as distinct species. In both species complexes similar genetic patterns were detected. Genetic diversification was higher across the islands of the Wallacea than across the islands of the Sahul Shelf. Divergence in E. roratus can be dated back about 1.38 million years ago, whereas in the younger T. haematodus it was 0.80 million years ago. Long distance dispersal was the most likely event for distribution patterns across the Wallacea and Sahul Shelf. The geographic origin of the species-complex Eclectus roratus spp. is supposed to be Wallacean, but for the species-complex Trichoglossus haematodus spp. it is supposed to be non-Wallacean. Trichoglossus euteles, so far considered a distinct species, clearly belongs to the Trichoglossus-haematodus-complex. The only case of sympatry in the complex is the distribution of T. (h.) euteles and T. h. capistratus on Timor, which means a rapid evolution from one ancestor into two distinct species within only 800,000 years. For all other taxa a Checkerboard distribution pattern is present. In this complex, 8 taxa are already treated as separate species (del Hoyo et al. 2014). Based on genetic evidence, the following populations are supported to represent phylogenetic units: (1) N New Guinea (haematodus) incl. Biak (rosenbergii), Bismarck Archipelago (massena), and New Caledonia (deplanchii); (2) Flores (weberi); (3) E Australia (moluccanus) incl. Aru Islands (nigrogularis) and S New Guinea (caeruleiceps); (4) N Australia (rubritorquis); (5) Timor 1st lineage (capistratus) incl. Sumba (fortis); (6) Bali and Lombok (mitchellii); (7) Sumbawa (forsteni); (8) Timor 2nd lineage (euteles). Those 8 phylogenetic units are not identical to the 8 species listed by del Hoyo et al. (2014). Several populations on smaller islands are under decline, a separate species status may lead to a higher conservation status in both species complexes, which are currently listed as “Least Concern”. Eclectus roratus is currently treated as monospecific. Based on genetic evidence, the following populations are suggested being treated as valid species: (1) Sumba (Eclectus cornelia), (2) Tanimbar Islands (E. riedeli), (3) Moluccas (E. roratus), and (4) New Guinea (E. polychloros incl. Aru Islands (E. aruensis), and Solomon Island (E. solomonensis).

Chromosomal Diversification Higher Than Molecular Variation in Astyanax aff. fasciatus (Teleostei, Characidae).

Comprising a large number of species, the genus Astyanax has been intensively studied by several approaches to elucidate its evolutionary relationships. Such studies have demonstrated that many nominal species are artificial clusters where distinct taxa are grouped under the same denomination. Astyanax aff. fasciatus stands out due to its high karyotypic diversity, since cytogenetic studies have reported three standard cytotypes (2n = 46, 48, and 50), as well as cases of sympatry between cytotypes, variant cytotypes, and B chromosomes. In this study, we attempted to evaluate the reliability of the chromosomal differences in relation to the analysis of the ATPase6/8 mitochondrial DNA (mtDNA) sequence, thereby providing subsidies to the evolutionary reconstruction of this group. Nine populations from four distinct hydrographic basins along Southeastern Brazil were analyzed. These are the first cytogenetic data collected for four of them. Fluorescent in situ hybridization with 5S rDNA probe evidenced the presence of a standard phenotype for the group and the existence of a new arrangement in the individuals from Ribeira de Iguape River. Besides the karyotypic variation, the genetic distance was low among the studied populations and some aspects of the evolutionary relationships among distinct cytotypes/populations could be ascertained by phylogeographic studies. The incipient molecular structuring of certain cytotypes in different hydrographic basins indicates the role of different evolutionary processes on the diversification of the group.

Sharing the space: distribution, habitat segregation and delimitation of a new sympatric area of subterranean rodents.

Subterranean rodents of the genus Ctenomys usually present an allopatric or parapatric distribution. Currently, two cases of sympatry have been recognized for the genus in the coastal dunes of southern Argentina and southern Brazil. In this context, they are ideal models to test hypotheses about the factors that delimit the patterns of space use and to understand interspecific interactions in small mammals. We investigated the vegetation structure, plant biomass and soil hardness selected by two species of subterranean rodents (Ctenomys flamarioni and C. minutus) when distributed in sympatry and allopatry from nine different areas along the line of coastal dunes in southern Brazil. In addition, our work presents a new record of a third area of sympatry for the genus Ctenomys. Ctenomys flamarioni and C. minutus show habitat segregation in the area where they occur in sympatry. These species show segregation in their selection of microhabitats, differing in relation to soil hardness, plant biomass, and plant cover. Ctenomys flamarioni showed a distinction in habitat selection when occurring in allopatry and sympatry, whereas C. minutus selected the same habitat characteristics under both conditions. A possible explanation to the observed pattern is that these species have acquired different adaptations over time which allows them the ability to exploit different resources and thus avoid competitive interactions all together.

The Taxonomic Status of Mico marcai (Alperin 1993) and Mico manicorensis (van Roosmalen et al. 2000) (Cebidae, Callitrichinae) from Southwestern Brazilian Amazonia

Species level taxonomic revisions of New World monkeys are scarce but necessary if we are to obtain a clear picture of this group’s diversity. In this work I revise taxonomically the little known marmoset Mico marcai¸ originally described as Callithrix argentata marcai Alperin, 1993, in light of more recently collected material. I show that this species is significantly different in facial pigmentation and pelage color from all other marmosets of the genus Mico in the Madeira–Tapajos interfluvium. The form first described as Callithrix manicorensis is treated as a junior synonym of Mico marcai, as there are no morphological differences or geographical barriers between the two putative taxa. Mico marcai occurs in the Aripuana–Manicore interfluvium, limited in the north by the Rio Madeira and in the south by enclaves of savannah vegetation. Mico marcai occurs in sympatry with Callibella humilis through at least part of its range, representing the only known case of sympatry of two species of marmoset. The northern range of Mico marcai is relatively undisturbed and has few human settlements, its southern limit, on the other hand, is crossed by a major Brazilian highway, and in the same region at least seven hydroelectric reservoirs are planned to be built.

Molecular, morphological and osteological differentiation of a new species of microhylid frog of the genus Stumpffia from northwestern Madagascar.

We describe a new small-sized microhylid frog of the genus Stumpffia and provide a preliminary survey of Stumpffia diversity in northern and northwestern Madagascar based on molecular and morphological data. Analysis of 68 previously published and 142 newly generated DNA sequences of a fragment of the mitochondrial 16S rRNA gene revealed a large genetic diversity within Stumpffia, with numerous strongly differentiated lineages occurring across Madagascar. The anal. ysis confirmed a clade formed exclusively by Stumpffia species occurring in north/northwestern Madagascar and contain. ing almost all species from this area. Based on DNA sequences of the RAG1 gene, we further assess that most of the deep mitochondrial lineages do not share haplotypes in this nuclear marker, even in the few cases of sympatry, which we interpret as confirmation of their status as independent evolutionary lineages. Micro-computed tomography revealed subtle differences in phalangeal formulae among some of these candidate species, providing additional taxonomic characters for future revisions of the genus. The newly described species Stumpffia analamaina sp. nov. occurs 27 km north-west of Antsohihy and is at present the southernmost confirmed Stumpffia of the north/northwestern clade. It is mainly characterized by a snout-vent length of 10-12 mm, advertisement calls consisting of a series of short melodious chirps, manus with four fingers and pes with five toes, with only slight length reduction of first finger and toe. It furthermore does not share haplotypes with any other Stumpffia species in 16S or RAG1, and has relatively longer hands and feet compared with other small-sized Stumpffia of the north/northwestern clade such as S. madagascariensis and S. pygmaea. The new species lives in an area of dry forest where it was found in leaf litter along a small stream bordered by degraded gallery vegetation. Due to the limited distributions of almost all species in the north/northwestern Stumpffia clade, the rareness of appropriate microhabitat around the type locality of S. analamaina sp. nov. and the rampant habitat destruction in this part of Madagascar, we propose a threat status of Critically Endangered for this new species.

Differential susceptibility to parasites of invasive and native species of Artemia living in sympatry: consequences for the invasion of A. franciscana in the Mediterranean region

Elucidating the mechanisms making a successful invader remains a central problem in invasion ecology. There is growing evidence supporting that the outcome of competition between species can be controlled by parasites. However our understanding of how parasites affect the interaction between native and invasive species is very limited. Here we explore the role of parasites as potential agents mediating the competitive exclusion of populations of Mediterranean brine shrimps Artemia by the exotic American A. franciscana, which is leading in most of the cases to the extinction of native Artemia populations. We compared the susceptibility of the invasive species and the native A.parthenogenetica to different cestode species using an exceptional case of sympatry in Aigues-Mortes saltern, South of France. The invader A. franciscana showed greatly reduced diversity, low prevalence and low burden of cestode larvae compared to its native congener. Infection in A. parthenogenetica was associated with high fitness costs. In particular, the most prevalent cestode, Flamingolepis liguloides caused castration in A. parthenogenetica. The results of this study suggest that the large impact of cestode on the native, but not the invading species, is likely to confer a decisive competitive advantage to the invader. It thus certainly contributes to explain the demographic success of A. franciscana in the Mediterranean region.

Rostral reconstruction of South American hippidiforms (Mammalia, Perissodactyla, Equidae): New anatomical and ecomorphological inferences

The Pleistocene Equus (Amerhippus) and hippidiforms frequently occur together in the South American fossil record, suggesting a possible case of sympatry and syntopy. Although resembling each other in their overall morphology, their rostra show distinct differences. While Equus (Amerhippus) resembles extant horses, hippidiforms are characterised by slender nasal bones, a retracted nasal notch at the level of M2–M3 or posterior to M3, and the presence of dorsal preorbital fossae of variable depth. Here we present an anatomical reconstruction of the muzzle of hippidiforms based on homologous patterns in the extant horse Equus caballus, together with a morphofunctional analysis of their rostra and a comparative analysis of premaxillary shape. The rostral morphology of hippidiforms suggests the presence of a developed upper lip with prehensile function, as occurs in extant black rhinoceros. This prehensile structure could be ecomorphologically related to browsing, thus reducing niche overlap with Equus (Amerh...

Neosclerocalyptus spp. (Cingulata: Glyptodontidae: Hoplophorini): cranial morphology and palaeoenvironments along the changing Quaternary

We propose that the particular high latitudinal distribution of Neosclerocalyptus (Glyptodontidae) and the cyclic nature of the Pleistocene glacial–interglacial events were factors that probably stimulated morphological evolution of its fronto-nasal sinuses, a feature unique among glyptodonts. The distributions of the species, and the majority of its records, are associated with sediments related to arid and semiarid environments. Four species are recognized during the last million years in southern South America. The first record of Neosclerocalyptus (N. pseudornatus) coincides with the “Great Patagonian Glaciation” and shows the lowest grade of pneumatization on its skull. Neosclerocalyptus paskoensis (the most derived species), limited to Oxygen Isotopic Stage 2, shows the greatest development of fronto-nasal pneumatization. The restricted geographic range of Neosclerocalyptus, the possible absence of geographic barriers during the Pleistocene, and the absence of cases of sympatry, allow us to speculate the existence of a single continuous lineage of successive species, showing an anagenetic process.

Diaceratherium massiliae nov. sp. des argiles oligocènes de Saint-André et Saint-Henri à Marseille et de Les Milles près d’Aix-en-Provence (SE de la France), premier grand Rhinocerotidae brachypode européen

A revision of all previously collected mammalian fossils from the two Late Oligocene sites of Saint-André and Saint-Henri in Marseille (both from the MP 26 reference-level) allows us to identify three Rhinocerotoidea species: Protaceratherium albigense, Ronzotherium romani, Diaceratherium massiliae nov. sp., and maybe a fourth one, Eggysodon cf. gaudryi. Only the first two were previously known there. D. massiliae nov. sp. is found together with R. romani; it is the first case of sympatry ever known between the two genera. D. massiliae nov. sp. is then the most ancient Diaceratherium in Europe, where the genus was previously unknown before the MP 29 reference-level. It is a very large species whose limb bones proportions foreshadow these of the later species of the genus, especially D. lemanense from the Late Oligocene-Early Miocene. This suggests a possible phylogenetic link between D. massiliae nov. sp. and D. lemanense, and the coexistence of at least two different but partially contemporaneous lineages among the European Diaceratherium. In Les Milles near Aix-en-Provence, also from the MP 26 reference-level, the three species P. albigense, R. romani and D. massiliae nov. sp. were also found.

The radiation of hydrobiid gastropods in New Zealand: A revision including the description of new species based on morphology and mtDNA sequence information

A revision of New Zealand hydrobiid gastropods resulted in the description of 46 new species out of a total of 64, which belong to 15 genera, nine of them new. This revision is based on morphological data as well as sequence information of two mtDNA fragments. The majority of species occur in seepages, springs and the ground‐water and many have very narrow ranges. The morphological diversification appears to be linked to these habitats. Their common feature is the absence of predators. The genetics of three morphologically distinct species found in springs and streamlets suggest they have only recently split from the common, widespread Potamopyrgus antipodarum. Predator pressure, on the other hand, may have stabilised shell shape of three genetically distinct but otherwise cryptic species of Potamopyrgus, which occur in rivers, lakes and estuaries. Many species occur sympatrically. In one case of sympatry P. antipodarum appeared to displace another, slightly smaller species into crevices and other microhabitats not accessible for the former. Phylogenetic relationships were reconstructed based on the concatenated mtDNA sequences using Bayesian analyses, maximum likelihood and minimum evolution (LogDet distances). The three reconstruction methods gave very similar results suggesting that heterogeneous base frequencies were not a confounding factor. Analyses of character evolution revealed convergence in the digestive system as well as in the female and male genitalia. Radular features suggested a relationship of New Caledonian and New Zealand hydrobiids.

GIS‐based niche models identify environmental correlates sustaining a contact zone between three species of European vipers

ABSTRACTThe current range of European vipers is mostly parapatric but local‐scale allopatric distribution is common and few cases of sympatry are known. In the High Course of Ebro River, northern Spain, there is a contact zone between Vipera aspis, V. latastei, and V. seoanei. Sympatry was detected between aspis and latastei and also specimens with intermediate morphological traits. Presence‐data at a local scale (1 × 1 km) and ecological niche‐based models manipulated in a GIS were used to (1) identify how environmental factors correlate with the distribution of the three vipers and with the location of the sympatry area, and (2) identify potential areas for viper occurrence and sympatry. Ensemble for casting with 10 Maximum Entropy models identified a mixture of topographical (altitude, slope), climatic (precipitation, evapotranspiration, and minimum and maximum temperature), and habitat factors (land cover) as predictors for viper occurrence. Similar predicted probabilities according to the variation of some environmental factors (indicating probable sympatry) were observed only for aspis‐latastei and aspis‐seoanei. In fact, areas of probable occurrence of vipers were generally allopatric but probable sympatry between vipers was identified for aspis‐latastei in 76 UTM 1 × 1 km squares, for aspis‐seoanei in 23 squares, and latastei‐seoanei in two squares. Environmental factors correlate with the location of this contact zone by shaping the species range: some enhance spatial exclusion and constrain distribution to spatially non‐overlapping ranges, while others allow contact between species. The distribution in the contact zone apparently results from the balance between the pressures exerted by the different environmental factors and in the sympatry area probably by interspecific competition. Further ecological and genetical data are needed to evaluate the dynamics of the probable hybrid zone. GIS and niche‐modelling tools proved to be powerful tools to identify environmental factors sustaining the location of contact zones.

A NEW SPECIES OF FUNNEL-EARED BAT (NATALIDAE: NATALUS) FROM MEXICO

A new species in the genus Natalus is described on the basis of 71 specimens found in museum collections. The body pelage of the new bat is unique among natalids in having hair bases much darker than hair tips. This new species is also characterized by short tibiae, legs and feet notably hairy, a long braincase, and a shallow rostrum. This species is known from 16 localities in Mexico, from both mountain and lowland areas. At some localities, it has been collected together with the previously known species Natalus stramineus. This constitutes the 1st known case of sympatry among species of the genus Natalus (sensu stricto).

Thaumatomyrmex strips millipedes for prey: a novel predatory behaviour in ants, and the first case of sympatry in the genus (Hymenoptera: Formicidae)

We describe, for the first time, the predatory behaviour ofThaumatomyrmex ants on millipedes of the family Polyxenidae, based on field observations ofT. atrox and a field and laboratory study ofT. contumax. The capture of the prey and the removal process of its body-covering setae by the ants before they eat the millipede are described. This specialized behaviour in at least two species of the genus, belonging to two distinct groups of species, indicates a general trend inThaumatomyrmex. We coupled this study with a comparative morphological analysis of the mouthparts and digestive tube of these and otherThaumatomyrmex species. Also, we report the first case of sympatry in the genus, which suggests thatThaumatomyrmex includes several species, and not only one highly variable taxon, as hypothetized earlier.

On the Ecology of Coexistence in Parthenogenetic and Bisexual Lizards of the GenusCnemidophorus

In the center of their distribution in North America, members of a complex of parthenogenetic and bisexual lizards of the genus Cnemidophorus may be found side by side with one or more of the others in a bewildering variety of patterns and ecological associations. Exactly why so many congeneric species are found living together and exactly what their ecological, physiological and geographical requirements are remains virtually unknown. Here 1 summarize all reported cases of sympatry among six species of Cnemidophorus and discuss in detail specific examples of some of these interactions based on several years of field collections and observations. In addition I present the first field experimental study designed to understand the ecological relationships of sympatry in Cnemidophorus .

Distribution of Cottus poecilopus Heckel and C. gobio L (Pisces) in Scandinavia

AbstractAndreasson. S. (Department of Animal Ecology, Lund University, Lund. Sweden.) Distribution of Cottus poecilopus Heckel and C. gobio L. (Pisces) in Scandinavia. Zool. Scripta 1(2): 69–78, 1972. –The distribution of the freshwater sculpins Cottus poecilopus Heckel and C. gobio L. in Scandinavia is presented. In southern Scandinavia there are rather defined limits between the species with C. poecilopus in the upper parts of the water courses and C. gobio in the lower reaches. There are few cases of sympatry. In northern Scandinavia there is a broad overlap and coexistence is common in the large rivers. The distribution pattern seems to be partly a result of an interaction between the species. In the South, the sharp limits are set by falls blocking the upstream dispersal of C. gobio thus indicating an exclusion of C. poecilopus in the lower reaches below the falls by the presence of C. gobio there. Where the species meet or overlap there is a habitat segregation.