Molecular phylogeny and evolution of the freshwater eels genus Anguilla based on the whole mitochondrial genome sequences

Molecular phylogenetic analyses were conducted using the whole mitochondrial genome sequences of all 18 species/subspecies of the freshwater eels genus Anguilla to infer their phylogenetic relationships and to evaluate hypotheses about the possible dispersal routes of this genus. The Bayesian and maximum likelihood analyses using a total of 15,187 sites of mitochondrial DNA sequences suggested that A. mossambica was the most basal species of anguillid eel, and that the other species (except for A. borneensis) formed three geographic clades: Atlantic (two species), Oceania (three species), and Indo-Pacific (11 species). The present study clearly indicated a sister relationship between the Atlantic and Oceanian species, which now have distantly separated geographic distributions. This suggests that the previous hypotheses to estimate the dispersal route of anguillid eels into the Atlantic Ocean based on the current geographic distribution of species are unsupported by the present more complete analysis. Alternatively, the unique geographic distribution of the present day species in the genus Anguilla appears to have resulted from multiple dispersal events. Although the age of the beginning of speciation among anguillid eels was tentatively estimated as 20 million years ago using a calibration for bony fishes of 7.3x10(-4) substitutions/site/million years, it is possible that this divergence time was underestimated because of the ecological characteristics of these fishes. The results of the present study suggest that the hypotheses for the dispersal route and divergence time of the genus Anguilla should be reconsidered.     

A phylogeny of freshwater eels inferred from mitochondrial genes

The genus Anguilla Shaw of Family Anguillidae consists entirely of freshwater eels, including 15 species and 2 subspecies. Conventionally, variegated markings and the length of the dorsal fin are the major morphological features used for reconstruction of phylogenetic relationships. The evolutionary history of these species remains unclear, especially for the Atlantic eels, whose habitats are far from the Metropolis in the Indo-Pacific region. This study reexamined the phylogenetic relationships of 12 Anguilla species by sequencing of the cytochrome b and 12S rRNA genes. In our analysis, species bearing similar coloration patterns or dorsal fin morphology are not necessarily clustered in the same clade, indicating that these morphological features might be unstable or might have occurred independently in different lineages during evolution. Combining our molecular data and geographical evidence, we speculate that (1) Anguilla first radiated about 20 million years ago, (2) the ancestors of Atlantic eels did not migrate by drifting through the Tethys Seaway at the leptocephali stage but instead trekked across the Central American Isthmus to the Sargasso Sea for spawning at the adult stage, and (3) multiple radiation events had occurred at the Metropolis during Anguilla evolution.     

Evolution of freshwater eels of the genus Anguilla: a probable scenario

We present a molecular phylogeny of freshwater eels from three oceans and give hypotheses to address major questions about the evolution and geographic distribution of this group. A phylogenetic tree obtained from mitochondrial cytochrome b sequences of eight species of Anguilla suggests that the African species A. mossambica and Australian species A. australis form a clade together with the two Atlantic species, the European eel, A. anguilla, and American eel, A. rostrata , whereas A. marmorata in the Indo-Pacific Ocean, A. reinhardti in northeastern Australia and the Japanese eel, A. japonica, in the northwestern Pacific are placed in another. Most speciation among the lineages is proposed to have occurred during the Eocene to Oligocene (45–30 million years ago, Ma). However, the two Atlantic species are estimated to have separated much later, approximately 10 Ma. The following evolutionary scenario for the dispersal and speciation of these species of anguillid eels is proposed based on general global paleogeography and paleo-circulation. Ancestral eels evolved during the Eocene or earlier, in the western Pacific Ocean near present-day Indonesia. A group derived from this ancestor dispersed westward, by transport of larvae in the global circum-equatorial current through the northern edge of the Tethys Sea. This group split into the ancestor of the European and American eels, which entered the Atlantic Ocean, and a second group, which dispersed southward and split into the east African species and Australian species.     

A new molecular phylogenetic hypothesis for the evolution of freshwater eels

Phylogenetic analysis of a segment of the mitochondrial 16S rDNA of eight Anguilla species from the Indo-Pacific region and from the North Atlantic revealed that the genus Anguilla appears to be surprisingly young, based upon the small observed maximum genetic distance of 4.8% and the high degree of morphological similarity among the species. The placement of A. marmorata as the most ancestral lineage suggests that the genus is likely to have originated in the Indo-Malayian region, from which it quickly spread. Two Pacific species, A. obscura and A. japonica, branched next. A. japonica was placed as sister group to all remaining species, which formed three clades: the first comprising A. australis, the second A. reinhardti and A. mossambica, and the third A. anguilla and A. rostrata. All analyzed specimens of A. rostrata originating from southern New Jersey to Nova Scotia had identical mitotypes, while five mitochondrial genotypes were found in Europe differing by zero to two substitutions. The two Atlantic eel species are very closely related; all surveyed specimens of A. anguilla differ by three to five substitutions from their American allies, corroborating the existence of two distinct biological species. This was also confirmed by restriction analysis of a 350-bp segment of the cytochrome b, in which American specimens were distinct in sharing a single diagnostic restriction site of HinfI. Our results suggest little to no gene flow between the two nominal Atlantic eel species.     

Molecular systematics of Xenocyprinae (teleostei: cyprinidae): taxonomy, biogeography, and coevolution of a special group restricted in East Asia

We surveyed mitochondrial DNA (mtDNA) sequence variation in the subfamily Xenocyprinae from China and used these data to estimate intraspecific, interspecific, and intergeneric phylogeny and assess biogeographic scenarios underlying the geographic structure of lineages. We sequenced 1140 bp of cytochrome b from 30 individuals of Xenocyprinae and one putative outgroup (Myxocypris asiaticus) and also sequenced 297 bp of ND4L, 1380 bp of ND4, 68 bp of tRNA(His), and 69 bp of tRNA(Ser) from 17 individuals of Xenocyprinae and the outgroup (M. asiaticus). We detected high levels of nucleotide variation among populations, species, and genera. The phylogenetic analysis suggested that Distoechodon hupeinensis might be transferred to the genus Xenocypris, the taxonomic status of the genus Plagiognathops might be preserved, and species of Xenocypris and Plagiognathops form a monophyletic group that is sister to the genus Distoechodon and Pseudobrama. The introgressive hybridization might occur among the populations of X. argentea and X. davidi, causing the two species to not be separated by mtDNA patterns according to their species identification, and the process and direction of hybridization are discussed. The spatial distributions of mtDNA lineages among populations of Xenocypris were compatible with the major geographic region, which indicated that the relationship between Hubei + Hunan and Fujian is closer than that between Hubei + Hunan and Sichuan. From a perspective of parasite investigation, our data suggested that the fauna of Hexamita in Xenocyprinae could be used to infer the phylogeny of their hosts.     

Comparative plastid genomics of Pinus species: Insights into sequence variations and phylogenetic relationships

Pinus L. is the largest genus of conifers and provides a classical model for studying species divergence and phylogenetic evolution by gymnosperms. However, our poor understanding of sequence divergence in the whole plastid genomes of Pinus species severely hinders studies of their evolution and phylogeny. Thus, we analyzed the sequences of 97 Pinus plastid genomes, including four newly sequenced genomes and 93 previously published plastomes, to explore the evolution and phylogenetic relationships in the genus Pinus. The complete chloroplast genomes of Pinus species ranged in size from 109 640 bp (P. cembra L.) to 121 976 bp (P. glabra Walter), and these genomes comprised circular DNA molecules in a similar manner to those of most gymnosperms. We identified 9108 repeats where most of the repeats comprised the dispersed type with 3983 (44%), followed by tandem repeats with 2999 (33%), and then palindromic repeats with 2126 (23%). Sixteen divergence hotspot regions were identified in Pinus plastid genomes, which could be useful molecular markers for future population genetics studies. Phylogenetic analysis showed that Pinus species could be divided into two diverged clades comprising the subgenera Strobus (single needle section) and Pinus (double needles section). Molecular dating suggested that the genus Pinus originated approximately 130.38 Mya during the late Cretaceous. The two subgenera subsequently split 85.86 Mya, which was largely consistent with the other molecular results based on partial DNA markers. These findings provide important insights into the sequence variations and phylogenetic evolution of Pinus plastid genomes.     

Molecular phylogenetic analysis of the genus Abies (Pinaceae) based on the nucleotide sequence of chloroplast DNA

A phylogenetic study of firs (Abies Mill.) was conducted using nucleotide sequences of several chloroplast DNA regions with a total length of 5580 bp. The analysis included 37 taxa, which represented the main evolutionary lineages of the genus, and Keteleeria davidiana. According to phylogenetic reconstruction, the Abies species were subdivided into six main groups, generally corresponding to their geographic distribution. The phylogenetic tree had three basal clades. All of these clades contained American species, and only one of them contained Eurasian species. The divergence time calibrations, based on paleobotanical data and the chloroplast DNA mutation rate estimates in Pinaceae, produced similar results. The age of diversification among the basal clades of the present-day Abies was estimated as the end of the Oligocene-beginning of Miocene. The age of the separation of Mediterranean firs from the Asian-North American branch corresponds to the Miocene. The age of diversification within the young groups of Mediterranean, Asian, and “boreal” American firs (A. lasiocarpa, A. balsamea, A. fraseri) was estimated as the Pliocene-Pleistocene. Based on the phylogenetic reconstruction obtained, the most plausible biogeographic scenarios were suggested. It is noted that the existing systematic classification of the genus Abies strongly contradicts with phylogenetic reconstruction and requires revision.     

Phylogeny of the Acipenseriformes: cytogenetic and molecular approaches

The review of the data on karyology and DNA content in Acipenseriformes shows that both extant families, the Polyodontidae and Acipenseridae, originated from a tetraploid ancestor which probably had a karyotype consisting of 120 macro- and microchromosomes and DNA content of about 3.2–3.8 pg per nucleus. The tetraploidization of the presumed 60-chromosome ancestor seems to have occurred at an early time of evolution of the group. The divergence of the Acipenseridae into Scaphirhyninae and Acipenserinae occurred without polyploidization. Within the genus Acipenser, polyploidization was one of the main genetic mechanisms of speciation by which 8n and 16n-ploid species were formed. Individual gene trees constructed for sequenced partial fragments of the 18S rRNA (230 base pairs, bp), 12S rRNA (185 bp), 16S rRNA (316 bp), and cytochrome b (270 bp) genes of two Eurasian (A. baerii and A. ruthenus) and two American (A. transmontanus and A. medirostris) species of Acipenser, Huso dauricus, Pseudoscaphirhynchus kaufmanni, Scaphirhynchus albus, and Polyodon spathula showed a low level of resolution; the analysis of a combined set of data for the four genes, however, gave better resolution. Our phylogeny based on molecular analysis had two major departures from existing morphological hypotheses: Huso dauricus is a sister-species to Acipenser instead of being basal to all acipenseriforms, and Scaphirhynchus and Pseudoscaphirhynchus do not form a monophyletic group. The phylogenetic tree constructed for the cytochrome b gene fragments (with inclusion of 7 additional species of Acipenser) supported the conclusion that octoploid species appeared at least three times within Acipenser.     

Phylogenetic systematics of Colotis and associated genera (Lepidoptera: Pieridae): evolutionary and taxonomic implications

We investigated the genetic diversity and phylogenetic placement of the butterflies in the genus Colotis and eight related pierid genera using sequence information from two mitochondrial and two nuclear genes. To establish the status of species, we initially barcoded 632 specimens representative of all genera and most species and subspecies in those genera. A subset was then selected for phylogenetic analysis where additional gene regions were sequenced: 16S rRNA (523 bp), EF‐1α (1126 bp) and wg (404 bp). DNA barcode results were largely congruent with the traditional classification of species in the Colotis group, but deep splits or lack of genetic divergence in some cases supported either species‐level differentiation or synonymy. Despite using information from four genes, the deeper nodes in our phylogeny were not strongly supported, and monophyly of the ‘Colotis group’ and the genera Colotis and Eronia could not be established. To preserve the monophyly of Colotis, we revive the genus Teracolus for three outlying species previously in Colotis (i.e. Colotis eris, Colotis subfasciatus and Colotis agoye), as well as the genus Afrodryas for Eronia leda. The position of Calopieris is unresolved although it appears to be well outside the molecular variation in Colotis (s.l.). A dispersal/vicariance analysis suggested that major diversification in Colotis (s.str.) occurred in Africa with subsequent dispersal to India and Madagascar.     

七种蟋蟀基因组DNA的RAPD多态性研究（直翅目：蟋蟀总科）

应用10种随机引物,对西北地区常见的3属7种蟋蟀进行RAPD多态性检测,共筛选出2种引物S142,S8可以对7个种扩增出清晰稳定的多态性片段,多态性片段共计58条,相对分子质量在320bp-2400bp之间。应用UPGMA（非加权配对算术平均法）对多态性片段进行聚类分析,构建树状图,推测系统发生关系。每一种蟋蟀均先各自聚为一类,棺头蟋属与油葫芦属间的遗传距离最小,亲缘关系最近,斗蟋属4个种间的亲缘关系较为复杂,明显分为2个支系,与传统分类并不一致。     

Are crocodiles really monophyletic?--Evidence for subdivisions from sequence and morphological data

Recently, the phylogenetic placement of the African slender snouted crocodile, Crocodylus cataphractus, has come under scrutiny and herein we address this issue using molecular and morphological techniques. Although it is often recognized as being a "basal" form, morphological studies have traditionally placed C. cataphractus within the genus Crocodylus, while molecular studies have suggested that C. cataphractus is very distinct from other Crocodylus. To address the relationship of this species to its congeners we have sequenced portions of two nuclear genes (C-mos 302bp and ODC 294bp), and two mitochondrial genes (ND6-tRNA(glu)-cytB 347bp and control region 457bp). Analyses of these molecular datasets, both as individual gene sequences and as concatenated sequences, support the hypothesis that C. cataphractus is not a member of Crocodylus or Osteolaemus. Examination of 165 morphological characters supports and strengthens our resurrection of an historic genus, Mecistops (Gray 1844) for cataphractus.     

中国野生稻及栽培稻核糖体DNA第一转录间隔区序列分析及其系统学意义

用 PCR技术从产于我国的 3种野生稻和亚洲栽培稻的 2个亚种中特异地扩增和测序了 r DNA的第一转录间隔区。普通野生稻 (Oryza rufipogon)、药用野生稻 (O.officinalis)、疣粒野生稻 (O.granu-lata)和栽培稻的两个亚种 (O.sativa ssp.indica,O.sativa ssp.japonica)的 ITS1序列为 1 93bp、1 94bp、2 1 8bp、1 94bp和 1 94bp,它们的 G/ C含量为 69.3%～ 72 .7% ,序列中位点趋异率为 1 .5%～ 1 0 .6%。序列的相似性比较和简约性分支分析的结果表明 ,普通野生稻与栽培稻的两个亚种之间的亲缘关系最为密切 ;药用野生稻与普通野生稻和与栽培稻的两个亚种的相似性都为 82 % ,说明它与 AA基因组有一定的亲缘关系 ;疣粒野生稻与普通野生稻、药用野生稻和栽培稻两个亚种的亲缘关系相对较远 ,它在稻属中可能是一个系统地位较独特的类群。以 ITS1序列构建的 3种野生稻和 2个栽培稻亚种的系统发育关系与前人用同工酶、叶绿体 DNA、线粒体 DNA和核 DNA资料重建的稻属的系统发育关系基本一致     

Identification and nearly full-length genome characterization of novel porcine bocaviruses

The genus bocavirus includes bovine parvovirus (BPV), minute virus of canines (MVC), and a group of human bocaviruses (HBoV1-4). Using sequence-independent single primer amplification (SISPA), a novel bocavirus group was discovered with high prevalence (12.59%) in piglet stool samples. Two nearly full-length genome sequences were obtained, which were approximately 5,100 nucleotides in length. Multiple alignments revealed that they share 28.7-56.8% DNA sequence identity with other members of Parvovirinae. Phylogenetic analyses indicated their closest neighbors were members of the genus bocavirus. The new viruses had a putative non-structural NP1 protein, which was unique to bocaviruses. They were provisionally named porcine bocavirus 1 and 2 (PBoV1, PBoV2). PBoV1 and PBoV2 shared 94.2% nucleotide identity in NS1 gene sequence, suggesting that they represented two different bocavirus species. Two additional samples (6V, 7V) were amplified for 2,407 bp and 2,434 bp products, respectively, including a partial NP1 gene and the complete VP1 gene; Phylogenetic analysis indicated that 6Vand 7V grouped with PBoV1 and PBoV2 in the genus of bocavirus, but were in the separate clusters. Like other parvoviruses, PBoV1, PBoV2, 6Vand 7V also contained a putative secretory phospholipase A(2) (sPLA(2)) motif in the VP1 unique region, with a conserved HDXXY motif in the catalytic center. The conserved motif YXGXF of the Ca(2+)-binding loop of sPLA2 identified in human bocavirus was also found in porcine bocavirus, which differs from the YXGXG motif carried by most other parvoviruses. The observation of PBoV and potentially other new bocavirus genus members may aid in molecular and functional characterization of the genus bocavirus.     

Diverse migration strategy between freshwater and seawater habitats in the freshwater eel genus Anguilla

The freshwater eels of the genus Anguilla, which are catadromous, migrate between freshwater growth habitats and offshore spawning areas. A number of recent studies, however, found examples of the temperate species Anguilla anguilla, Anguilla rostrata, Anguilla japonica, Anguilla australis and Anguilla dieffenbachii that have never migrated into fresh water, spending their entire life history in the ocean. Furthermore, those studies found an intermediate type between marine and freshwater residents, which appear to frequently move between different environments during their growth phase. The discovery of marine and brackish-water residents Anguilla spp. suggests that they do not all have to be catadromous, and it calls into question the generalized classification of diadromous fishes. There has been little available information, however, concerning migration in tropical Anguilla spp. Anguilla marmorata, shows three fluctuation patterns: (1) continuous residence in fresh water, (2) continuous residence in brackish water and (3) residence in fresh water after recruitment, while returning to brackish water. Such migratory patterns were found in other tropical species, Anguilla bicolor bicolor and Anguilla bicolor pacifica. In A. b. bicolor collected in a coastal lagoon of Indonesia, two further patterns of habitat use were found: (1) constantly living in either brackish water or sea water with no freshwater life and (2) habitat shift from fresh water to brackish water or sea water. The wide range of environmental habitat use indicates that migratory behaviour of tropical Anguilla spp. is facultative among fresh, brackish and marine waters during their growth phases after recruitment to the coastal areas. Further, the migratory behaviours of tropical Anguilla spp. appear to differ in each habitat in response to inter and intra-specific competition. The results suggest that tropical Anguilla spp. have a flexible pattern of migration, with an ability to adapt to various habitats and salinities. The ability of anguillids to reside in environments of various salinities would be a common feature between tropical and temperate species without a latitudinal cline. Thus, the migration of Anguilla spp. into fresh water is clearly not an obligatory behaviour. This evidence of geographical variability among Anguilla spp. suggests that habitat use is determined by environmental conditions in each site.     

Phylogenetic reconstructions in the genus Capra (Bovidae, Artiodactyla) based on the mitochondrial DNA analysis

Mitochondrial genome fragments were examined in all species of the genus Capra (Bovidae, Artiodactyla). Phylogenetic analysis was carried out using 59 cytochrome b gene sequences (392 bp), and 22 sequences of the mtDNA variable fragment (402 bp). In the control region, two unique deletions were revealed. One of the deletions was found only in Capra cilindricornis (17 bp), while another one grouped C. caucasica with C. aegagrus (1 bp). The group of Caucasian wild goats splits into two clades, and furthermore, the sequences of C. caucasica demonstrate remarkable similarity to the sequences of C. aegagrus, while C. cylindricus seems to have evolved independently for a long period of time. It was demonstrated that C. pyrenaica and C. ibex were extremely close to one another. Capra sibirica formed an outer group relative to the other species, and according to our data, was the most ancient species of the genus. On the contrary, genetic distance separating C. falconeri (the most independent species of the genus related to its morphology) from the other species is small.     

Molecular systematics and global phylogeography of angel sharks (genus Squatina)

Angel sharks of the genus Squatina represent a group comprising 22 extant benthic species inhabiting continental shelves and upper slopes. In the present study, a comprehensive phylogenetic reconstruction of 17 Squatina species based on two mitochondrial markers (COI and 16S rRNA) is provided. The phylogenetic reconstructions are used to test biogeographic patterns. In addition, a molecular clock analysis is conducted to estimate divergence times of the emerged clades. All analyses show Squatina to be monophyletic. Four geographic clades are recognized, of which the Europe–North Africa–Asia clade is probably a result of the Tethys Sea closure. A second sister group relationship emerged in the analyses, including S. californica (eastern North Pacific) and S. dumeril (western North Atlantic), probably related to the rise of the Panamanian isthmus. The molecular clock analysis show that both lineage divergences coincide with the estimated time of these two geological events.     

Multigenic and morphometric differentiation of ground squirrels (Spermophilus, Scuiridae, Rodentia) in Turkey, with a description of a new species

This study reports on the molecular phylogenetics of ground squirrels, genus Spermophilus, in Turkey using cytochrome b (1140bp), part of the D-loop and flanking tRNAs (572bp), X chromosome (867-1051bp) and Y chromosome (983-989bp) DNA sequences. Individuals also were characterized by karyotype and with geometric morphometric analyses of mandibles and skulls. Two hundred fourteen individuals from 91 localities were studied. All the data support the recognition of a new species in SW Anatolia: the Taurus ground squirrel Spermophilus taurensis sp. nov. The new species has a small distribution in the Taurus Mountains in an area that is a hotspot for biodiversity. Molecular clock analysis suggests that the new species diverged from the European ground squirrel, Spermophilus citellus, about 2.5 million years ago and that the ancestor of these two species diverged from the widespread Anatolian ground squirrel, Spermophilus xanthoprymnus, about 5 million years ago. Morphometric differentiation in skull and mandible shape among the three species is incomplete, but statistically significant. S. xanthoprymnus is subdivided into five cytochrome b phylogroups and we use these data to infer the location of glacial refugia where the species lived during the last glacial maximum. This study illustrates the potential of combined molecular and morphometric studies to uncover new Anatolian species and to reconstruct their phylogeographic history. The new species is important for squirrel taxonomy and for understanding Eurasian mammal evolution.     

Distribution of leptocephali of the freshwater eels,genus <Emphasis Type="Italic">Anguilla</Emphasis>, in the waters off west Sumatra in the Indian Ocean

A research cruise was conducted in the eastern Indian Ocean off west Sumatra, Indonesia, in June 2003 to learn about the spawning and larval ecology of the tropical freshwater eels of the genus Anguilla in the region. A total of 43 anguillid leptocephali were collected during the cruise and they were genetically identified as 41 Anguilla bicolor bicolor, 1 Anguilla marmorata, and 1 Anguilla interioris. A. bicolor bicolor leptocephali were 44.1–55.5 mm TL and most of them were at the fully grown stage. Reexamination of the historical data of Jespersen (1942) also suggested a relatively low abundance of small size leptocephali (<40 mm) of this species off west Sumatra. Although the study area has long been considered to be a spawning site of A. bicolor bicolor, the distributions of leptocephali from the two surveys and the patterns of ocean currents in the region suggest the possibility that the main spawning area of this species is located farther offshore.     

Deep genomic analysis of Coelastrella saipanensis (Scenedesmaceae,Chlorophyta): comparative chloroplast genomics of Scenedesmaceae

Many species belonging to the coccoid green algae genus Coelastrella are considered potential candidates for the large-scale production of natural pigments and biofuels. However, little is known about the structural, functional and molecular aspects of the chloroplast genomes (cpDNAs) of this genus. In the present study, the complete sequence of the cpDNA of strain FACHB-2138, which was further identified as Coelastrella saipanensis Hanagata based on morphological and molecular analyses, was elucidated. The 196 140 bp cpDNA sequence that was assembled as a circular map was found to possess the typical quadripartite structure. The two identical copies of 11 897 bp inverted repeat (IR) sequences were separated from one another by single copy regions. The large single copy region (LSC) was 104 949 bp, whereas the small single copy region (SSC) was 67 397 bp. The cpDNA encoded a total of 96 unique genes, which included 67 protein-coding genes, three rRNA genes and 26 tRNA genes. A total of 19 group I introns were annotated in this genome. Comparative analyses with three species from the family Scenedesmaceae showed C. saipanensis had a slightly expanded genome, higher GC content and less skewed distribution of its genes between the two DNA strands than that of the other three species. The cpDNA data deduced from the present study helps to expand our present understanding of plant systematics and phylogenetic reconstruction, and identify the possible biotechnological applications of the species belonging to the studied taxa.     

Climate and Soil Type Together Explain the Distribution of Microendemic Species in a Biodiversity Hotspot

The grasshopper genus Caledonula, endemic to New Caledonia, was studied to understand the evolution of species distributions in relation to climate and soil types. Based on a comprehensive sampling of 80 locations throughout the island, the genus was represented by five species, four of which are new to science, of which three are described here. All the species have limited distributions in New Caledonia. Bioclimatic niche modelling shows that all the species were found in association with a wet climate and reduced seasonality, explaining their restriction to the southern half of the island. The results suggest that the genus was ancestrally constrained by seasonality. A molecular phylogeny was reconstructed using two mitochondrial and two nuclear markers. The partially resolved tree showed monophyly of the species found on metalliferous soils, and molecular dating indicated a rather recent origin for the genus. Adaptation to metalliferous soils is suggested by both morphological changes and radiation on these soils. The genus Caledonula is therefore a good model to understand the origin of microendemism in the context of recent and mixed influences of climate and soil type.