PHYLOGENY OF THE EUGLENOID LORICATE GENERA TRACHELOMONAS AND STROMBOMONAS (EUGLENOPHYTA) INFERRED FROM NUCLEAR SSU AND LSU rDNA1

Previous studies using the nuclear SSU rDNA and partial LSU rDNA have demonstrated that the euglenoid loricate taxa form a monophyletic clade within the photosynthetic euglenoid lineage. It was unclear, however, whether the loricate genera Trachelomonas and Strombomonas were monophyletic. In order to determine the relationships among the loricate taxa, SSU and LSU nuclear rDNA sequences were obtained for eight Strombomonas and 25 Trachelomonas strains and combined in a multigene phylogenetic analysis. Conserved regions of the aligned data set were used to generate maximum‐likelihood (ML) and Bayesian phylogenies. Both methods recovered a strongly supported monophyletic loricate clade with Strombomonas and Trachelomonas species separated into two sister clades. Taxa in the genus Strombomonas sorted into three subclades. Within the genus Trachelomonas, five strongly supported subclades were recovered in all analyses. Key morphological features could be attributed to each of the subclades, with the major separation being that all of the spine‐bearing taxa were located in two sister subclades, while the more rounded, spineless taxa formed the remaining three subclades. The separation of genera and subclades was supported by 42 distinct molecular signatures (33 in Trachelomonas and nine in Strombomonas). The morphological and molecular data supported the retention of Trachelomonas and Strombomonas as separate loricate genera.     

Molecular phylogeny and divergence times of Onosma (Boraginaceae s.s.) based on nrDNA ITS and plastid rpl32‐trnL(UAG) and trnH–psbA sequences

We analysed 87 species of Onosma (Boraginaceae) from throughout its distribution range to investigate its evolutionary history. Using nrDNA ITS and two plastid (rpl32‐trnL_(UAG) and trnH–psbA) markers, we reconstructed phylogenetic relationships within Onosma by conducting maximum parsimony, maximum likelihood, Bayesian, and BEAST analyses. The analyses revealed that Onosma as currently circumscribed is not monophyletic. However, the vast majority of Onosma species appear to belong to a single clade, the so‐called Onosma s.s. Outside of this core clade is a clade containing O. rostellata, a subclade of Sino‐Indian species and Maharanga emodii. Podonosma orientalis (as O. orientalis) appear only distantly related to Onosma but is more closely related to Alkanna, as also suggested in previous molecular studies. The Onosma s.s. clade includes all representatives of O. sect. Onosma, and encompasses three subsections, i.e. Onosma, Haplotricha and Heterotricha, corresponding to asterotrichous, haplotrichous and heterotrichous groups, respectively, but none of these subsections was retrieved as monophyletic. We observed significant incongruence between nuclear and chloroplast phylogenies regarding the phylogenetic status of the heterotrichous group. A dozen of the Iranian haplotrichous species formed a lineage which may not hybridize with asterotrichous species. Divergence time estimates suggested that the early radiation of Onosma s.l. took place at the Oligocene‐Miocene boundary and the diversification within Onosma s.s. occurred during middle to late Miocene and Pliocene.     

Photosynthetic pigments of oceanic Chlorophyta belonging to prasinophytes clade VII

The ecological importance and diversity of pico/nanoplanktonic algae remains poorly studied in marine waters, in part because many are tiny and without distinctive morphological features. Amongst green algae, Mamiellophyceae such as Micromonas or Bathycoccus are dominant in coastal waters while prasinophytes clade VII, yet not formerly described, appear to be major players in open oceanic waters. The pigment composition of 14 strains representative of different subclades of clade VII was analyzed using a method that improves the separation of loroxanthin and neoxanthin. All the prasinophytes clade VII analyzed here showed a pigment composition similar to that previously reported for RCC287 corresponding to pigment group prasino‐2A. However, we detected in addition astaxanthin for which it is the first report in prasinophytes. Among the strains analyzed, the pigment signature is qualitatively similar within subclades A and B. By contrast, RCC3402 from subclade C (Picocystis) lacks loroxanthin, astaxanthin, and antheraxanthin but contains alloxanthin, diatoxanthin, and monadoxanthin that are usually found in diatoms or cryptophytes. For subclades A and B, loroxanthin was lowest at highest light irradiance suggesting a light‐harvesting role of this pigment in clade VII as in Tetraselmis.     

Genetic differentiation of Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) biotype Q based on mitochondrial DNA markers

In the present study, genetic differentiation of Bemisia tabaci (Gennadius) biotype Q was analyzed based on mitochondrial cytochrome oxidase I (mt COI) gene sequence. The results showed that B. tabaci biotype Q could be separated into two subclades, which were labeled as subclades Q1 and Q2. Subclade Q1 was probably indigenous to the regions around the Mediterranean area and subclade Q2 to Israel or Cyprus. It was because B. tabaci was composed of several genetically distinct groups with a strong geographical association between more closely related biotypes. Not all of the B. tabaci biotype Q in the non‐Mediterranean countries come from the same regions. Until now, all B. tabaci biotype Q in China were grouped into subclade Q1. The B. tabaci biotype Q introduced into the US included both subclades Q1 and Q2. The genetic structure analysis showed higher genetic variation of subclade Q1 than that of subclade Q2.     

Australian Laurencia majuscula (Rhodophyta,Rhodomelaceae) and the Brazilian Laurencia dendroidea are conspecific

Morphological and molecular studies have been undertaken on two species of the red algal genus Laurencia J.V.Lamouroux: Laurencia majuscula (Harvey) A.H.S. Lucas and Laurencia dendroidea J.Agardh, both from their type localities. The phylogenetic position of these species was inferred by analysis of the chloroplast‐encoded rbcL gene sequences from 24 taxa. In all phylogenetic analyses, the Australian Laurencia majuscula and the Brazilian L. dendroidea formed a well‐supported monophyletic clade within the Laurencia sensu stricto. This clade was divided into two subclades corresponding to each geographical region; however, the genetic divergence between Australian L. majuscula and Brazilian L. dendroidea was only 0–1.35%. Examination of the type specimens and sequences of freshly collected samples of both Laurencia majuscula and L. dendroidea show the two to be conspecific despite their disjunct type localities.     

Molecular phylogeny evidence of altitudinal distribution and habitat adaptation in Korean Ephemera species (Ephemeroptera: Ephemeridae)

Molecular phylogeny of the four Korean Ephemera species, Ephemera orientalis, E. sachalinensis, E. strigata, and E. separigata, was inferred from 630 bp sequences of the partial mitochondrial cytochrome c oxidase I (COI) gene. Results indicated that mean intraspecific sequence divergences were 0.70%, whereas mean interspecific divergences were 15.75%, and 17 samples were distinguished to four species correctly by COI sequences. The results also demonstrated that four species of Korean Ephemera assembled a monophyletic group with high support in maximum parsimony and maximum likelihood analyses. This Ephemera group was divided into two major clades of E. orientalis–E. sachalinensis and E. strigata–E. separigata. Furthermore, we demonstrated that this phylogeny explained altitudinal and habitat adaptations of Korean Ephemera species. The E. orientalis–E. sachalinensis clade, a widespread and lowland‐adapted mayfly group, retained plesiomorphic traits such as paired stripes on abdominal segments and was regarded as plesiotypic in terms of habitat adaptation, compared to the geographically more limited and upland‐adapted E. strigata–E. separigata clade.     

Genetic Variation and Evolution of the Alpine Bamboos (Poaceae: Bambusoideae) using DNA Sequence Data

Thamnocalamus , Fargesia and Yushania, of the alpine bamboos and one species of Ampelocalamus as an out-group were studied. The results indicated that Thamnocalamus spathiflorus var. crassinodus and the Fargesia spathacea clade form the basal groups but bootstrap support was weak. Among the rest of the species, including species previously placed in Fargesia (plus Borinda) and Yushania, the F. yunnanensis subclade and the F. communis subclade were recognized but internal support for such groups was again low. The result indicated that, Fargesia and Yushania as delimited by morphological characters, are not monophyletic in the ITS phylogeny and require further resolution. We revealed relatively high levels of genetic variability in the alpine bamboos and showed that the ITS region could be used to improve generic delimitation of the woody bamboos in general. Received 18 September 2000/ Accepted in revised form 9 May 2001     

Phylogenetic analysis of the grape family (Vitaceae) based on three chloroplast markers

Seventy-nine species representing 12 genera of Vitaceae were sequenced for the trnL-F spacer, 37 of which were subsequently sequenced for the atpB-rbcL spacer and the rps16 intron. Phylogenetic analysis of the combined data provided a fairly robust phylogeny for Vitaceae. Cayratia, Tetrastigma, and Cyphostemma form a clade. Cyphostemma and Tetrastigma are each monophyletic, and Cayratia may be paraphyletic. Ampelopsis is paraphyletic with the African Rhoicissus and the South American Cissus striata nested within it. The pinnately leaved Ampelopsis form a subclade, and the simple and palmately leaved Ameplopsis constitutes another with both subclades containing Asian and American species. Species of Cissus from Asia and Central America are monophyletic, but the South American C. striata does not group with other Cissus species. The Asian endemic Nothocissus and Pterisanthes form a clade with Asian Ampelocissus, and A. javalensis from Central America is sister to this clade. Vitis is monophyletic and forms a larger clade with Ampelocissus, Pterisanthes, and Nothocissus. The eastern Asian and North American disjunct Parthenocissus forms a clade with Yua austro-orientalis, a species of a small newly recognized genus from China to eastern Himalaya. Vitaceae show complex multiple intercontinental relationships within the northern hemisphere and between northern and southern hemispheres.     

基于5个基因片段的野胡麻属系统位置研究

对单种属野胡麻属(原隶属于广义玄参科)及其可能近缘类群广泛取样,选择合适外类群,通过对4个叶绿体基因联合数据(trnL-F、rps16、rbcL、rps2)、核基因ITS片段、叶绿体基因与核基因ITS片段联合数据,进行最大简约法和贝叶斯法分析,探讨野胡麻属在科级系统位置及其与近缘类群系统发育关系。结果表明,所有系统树都支持野胡麻属先和肉果草属构成姐妹群关系,叶绿体基因联合系统树支持率分别为97%[Bootstrap(BS)]和100%[Posterior probability(PP)];ITS系统树支持率分别为99%(BS)和100%(PP);叶绿体基因和ITS联合系统树支持率均为100%(BS和PP)。野胡麻属、肉果草属与通泉草属一起构成一单系群,叶绿体基因联合系统树、ITS系统树、叶绿体基因和ITS联合系统树的支持率均为100%(BS和PP)。形态学证据也支持野胡麻属、肉果草属和通泉草属这3个属的近缘关系。本研究结果支持单种属野胡麻属隶属于透骨草科的通泉草亚科,与肉果草属亲缘关系最近,这两个属进而与通泉草属近缘,可能隶属于通泉草属内,与岩白翠亲缘关系较近,也可能与通泉草属互为姐妹群关系。     

Symbiotic green algae in eggs of Hynobius nigrescens,an amphibian endemic to Japan

The egg capsules of some amphibians' eggs are known to become green colored before hatching. This is due to the increase of green symbionts in the egg capsule surrounding the embryo. The green symbionts in North American amphibian eggs were reported to be unicellular green algae in the Oophila‐clade of Volvocales, Chlorophyceae. However, it remains unclear whether this is also the case in other parts of the world. In this study, we analyzed the green symbionts in green‐colored eggs of Hynobius nigrescens, an amphibian endemic to Japan, obtained from five distinct locations. Microscopic observations revealed that the green symbionts were similar in appearance to Oophila amblystomatis, which was reported in some amphibian eggs in North America, in which non‐motile cells of the algae had thick cell walls with reticulate protuberances. PCR‐DGGE followed by phylogenetic analyses of partial 18S rRNA sequences revealed that the symbionts from the five locations were identical and most likely unialgal in each egg capsule. They formed an independent subclade within the Oophila‐clade, indicating that H. nigrescens has a unique symbiont. Our data are consistent with the previous report on North American amphibian eggs and support the specific symbiotic relationships between Oophila‐clade symbionts and the eggs of amphibians. This is the first report on the specific symbiont‐and‐host association between an Oophila‐clade symbiont and an amphibian outside of North America. We also discuss several possibilities regarding the origin of green symbionts (vertical transmission or invasion) on the basis of the discovery and detailed observation of H. nigrescens eggs without any green symbionts.     

CAROTENOID COMPOSITIONS OF CLADOPHORA BALLS (AEGAGROPILA LINNAEI) AND SOME MEMBERS OF THE CLADOPHORALES (ULVOPHYCEAE,CHLOROPHYTA): THEIR TAXONOMIC AND EVOLUTIONARY IMPLICATION1

Photosynthetic pigments were analyzed by HPLC for 27 samples of the Cladophorales (Ulvophyceae, Chlorophyta). The carotenoid compositions of the examined algae were classified into three types based on the final compound of biosynthesis of the α‐carotene branch: lutein type, characterized by containing lutein as a major carotenoid and lacking loroxanthin and siphonaxanthin; loroxanthin type, characterized by containing loroxanthin and lacking siphonaxanthin; and siphonaxanthin type, characterized by containing siphonaxanthin. We constructed molecular phylogenetic tree of the species examined in the present study using 18S rRNA gene sequences and mapped the carotenoid types of the species onto the tree. The molecular phylogenetic analysis divided the Cladophorales into two major clades, clade 1 and Aegagropila‐clade (clade 2), and divided clade 1 into subclade 1‐1 and subclade 1‐2. All the examined species positioned in the Aegagropila‐clade and those of the subclade 1‐1 belonged to the loroxanthin type, whereas both lutein type and siphonaxanthin type appeared only in the subclade 1‐2. The clades delineated by molecular phylogenetic analysis were congruent with distribution of the carotenoid types, indicating that the carotenoid types are of taxonomic significance in the Cladophorales. Considering the distribution pattern of these carotenoid types and minimum state changes in the Cladophorales, we concluded that the loroxanthin type was the primitive (plesiomorphic) state and the siphonaxanthin type and lutein type appeared in the subclade 1‐2 as advanced (apomorphic) state within this order and suggested that the cladophoralean siphonaxanthin type would have been secondarily acquired.     

Molecular phylogeny of relict-endemic <Emphasis Type="Italic">Liquidambar orientalis</Emphasis> Mill based on sequence diversity of the chloroplast-encoded <Emphasis Type="Italic">mat</Emphasis>K gene

The genetic diversity and evolutionary divergence in Liquidambar species and Liquidambar orientalis varieties were compared with respect to the matK gene. A total of 66 genotypes from 18 different populations were sampled in southwestern Turkey. The matK region, which is about 1,512 bp in length, was sequenced and studied. L. orientalis, L. styraciflua, and L. formosana had similar magnitude of nucleotide diversity, while L. styraciflua and L. acalycina possessed higher evolutionary divergence. The highest evolutionary divergence was found between L. styraciflua and eastern Asian Liquidambar species (0.0102). However, the evolutionary divergence between L. orientalis and other species was of a similar magnitude. The maximum-parsimony phylogenetic tree showed that L. styraciflua and L. orientalis formed a closer clade while East Asian species were in a separate clade. This suggests that the North Atlantic Land Bridge through southern Greenland may have facilitated continuous distribution of Liquidambar species from southeastern Europe to eastern North America in early Tertiary period. The maximum-parsimony tree with only 18 Oriental sweetgum populations indicated that there were two main clusters: one with mainly L. orientalis var. integriloba and the other with var. orientalis and undetermined populations. High nucleotide diversity (0.0028) and divergence (0.00072) were found in L. orientalis var. integriloba populations and Muğla-1 geographical region. This region could be considered as the major refugium and genetic diversity center for the species. The low genetic diversity and divergence at intraspecies level suggest that L. orientalis populations in Turkey share an ancestral polymorphism from which two varieties may have evolved.     

Phylogeography of the fungal pathogen Histoplasma capsulatum

Until recently, Histoplasma capsulatum was believed to harbour three varieties, var. capsulatum (chiefly a New World human pathogen), var. duboisii (an African human pathogen) and var. farciminosum (an Old World horse pathogen), which varied in clinical manifestations and geographical distribution. We analysed the phylogenetic relationships of 137 individuals representing the three varieties from six continents using DNA sequence variation in four independent protein‐coding genes. At least eight clades were idengified: (i) North American class 1 clade; (ii) North American class 2 clade; (iii) Latin American group A clade; (iv) Latin American group B clade; (v) Australian clade; (vi) Netherlands (Indonesian?) clade; (vii) Eurasian clade and (viii) African clade. Seven of eight clades represented genetically isolated groups that may be recognized as phylogenetic species. The sole exception was the Eurasian clade which originated from within the Latin American group A clade. The phylogenetic relationships among the clades made a star phylogeny. Histoplasma capsulatum var. capsulatum individuals were found in all eight clades. The African clade included all of the H. capsulatum var. duboisii individuals as well as individuals of the other two varieties. The 13 individuals of var. farciminosum were distributed among three phylogenetic species. These findings suggest that the three varieties of Histoplasma are phylogenetically meaningless. Instead we have to recognize the existence of genetically distinct geographical populations or phylogenetic species. Combining DNA substitution rates of protein‐coding genes with the phylogeny suggests that the radiation of Histoplasma started between 3 and 13 million years ago in Latin America.     

Range expansion during the Pleistocene drove morphological radiation of the fir genus (Abies,Pinaceae) in the Qinghai‐Tibet Plateau and Himalayas

Range expansion caused by climate oscillations in the past probably promoted morphological radiation in a few plant groups. In this study, we aim to test this hypothesis through phylogeographical analysis of the cold‐tolerant fir genus (Abies) in the Qinghai‐Tibet Plateau (QTP) and Himalayas, where it comprises 12 described species. We examined sequence variation in two maternally inherited mitochondrial (mt) DNA fragments (nad5‐4 and nad7‐1) and two paternally inherited plastid DNA fragments (trnS‐G and trnL‐F) for 733 individuals from 75 populations of the species in a monophyletic group. Only six mtDNA haplotypes were recovered, but five were shared between multiple species and one occurred at a high frequency, providing strong evidence of range expansion. Forty‐three plastid DNA haplotypes were detected, 19 of which were shared between species and three occurred at high frequency. Network, mismatch and Bayesian skyline plot analyses of all plastid DNA haplotypes from this clade clearly suggested range expansion. This expansion was dated as having occurred during the longest and most extensive glaciation in the Pleistocene. Our results therefore supported the range expansion hypothesis for this clade of Abies during the Pleistocene; expansion probably drove the morphological radiation of the clade in the QTP and Himalayas, although it remains unclear whether the different morphotypes should be acknowledged as independent, reproductively isolated species. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 179 , 444–453.     

Molecular systematics and Holarctic phylogeography of cestodes of the genus Anoplocephaloides Baer, 1923 s. s. (Cyclophyllidea,Anoplocephalidae) in lemmings (Lemmus,Synaptomys)

The present molecular systematic and phylogeographic analysis is based on sequences of cytochrome c oxidase subunit 1 (cox1) (mtDNA) and 28S ribosomal DNA and includes 59 isolates of cestodes of the genus Anoplocephaloides Baer, 1923 s. s. (Cyclophyllidea, Anoplocephalidae) from arvicoline rodents (lemmings and voles) in the Holarctic region. The emphasis is on Anoplocephaloides lemmi (Rausch 1952) parasitizing Lemmus trimucronatus and Lemmus sibiricus in the northern parts of North America and Arctic coast of Siberia, and Anoplocephaloides kontrimavichusi (Rausch 1976) parasitizing Synaptomys borealis in Alaska and British Columbia. The cox1 data, 28S data and their concatenated data all suggest that A. lemmi and A. kontrimavichusi are both non‐monophyletic, each consisting of two separate, well‐defined clades, that is independent species. As an example, the sister group of the clade 1 of A. lemmi, evidently representing the ‘type clade’ of this species, is the clade 1 of A. kontrimavichusi. For A. kontrimavichusi, it is not known which one is the type clade. There is also fairly strong evidence for the non‐monophyly of Anoplocephaloides dentata (Galli‐Valerio, 1905)‐like species, although an earlier phylogeny suggested that this multispecies assemblage may be monophyletic. The results suggest a deep phylogenetic codivergence of Lemmus spp. and A. lemmi, primarily separating the two largely allopatric host and parasite species at the Kolyma River in east Siberia. There are also two allopatric sublineages within each main clade/species of A. lemmi and Lemmus, but the present distributions of the sublineages within the eastern L. trimucronatus and clade 1 of A. lemmi are not concordant. This discrepancy may be most parsimoniously explained by an extensive westward distributional shift of the easternmost parasite subclade. The results further suggest that the clade 1 of A. kontrimavichusi has diverged through a host shift from the precursor of L. trimucronatus to S. borealis.     

Polyphyly of the genus Apalis and a new generic name for the species pulchra and ruwenzorii

The genus Apalis is a member of the African forest warblers clade of the Cisticolidae. In view of its morphological diversity, it was suggested that this genus needs a taxonomic revaluation. For this, we sequenced a nuclear intron (myoglobin intron 2) and two mitochondrial protein‐coding genes (ND2 and ND3). The 2016 bp of sequence data obtained were aligned and subjected to parsimony, maximum likelihood and Bayesian inference. All three genes strongly reject the monophyly of Apalis but support the placing of all apalises within a broader clade of forest cisticolids which also includes Urolais. Within this forest clade, a subclade is defined which includes the genera Urolais, Schistolais and a well‐supported clade comprising three afromontane species, the Black‐collared Apalis Apalis pulchra, the Ruwenzori Apalis Apalis ruwenzorii and the African Tailorbird Artisornis. This subclade is sister to other members of Apalis, including the type species of the genus the Bar‐throated Apalis Apalis thoracica. A new generic name, Oreolais, is suggested for the Black‐collared and Ruwenzori Apalises.     

Molecular phylogenetic analysis of Euphorbiaceae sensu stricto based on plastid and nuclear DNA sequences and ovule and seed character evolution

A phylogenetic analysis of Euphorbiaceae sensu stricto is presented using sequences from rbcL, atpB, matK and 18S rDNA from 85 species and 83 genera. The combined analysis of four molecular markers resulted in only one most parsimonious tree and also generated new supported clades, which include Euphorbioideae + Acalyphoideae s.s., subclades A2 + A3, subclades A5 + A6 and a clade uniting subclades A2–A8 within Acalyphoideae s.s. A palisadal exotegmen is a possible synapomorphy for all the Euphorbiaceae, except for the subfamily Peroideae. The presence of vascular bundles in the inner integument and a thick inner integument were shown to be synapomorphies for the clade of inaperturate and articulated crotonoids and for the large clade of Euphorbioideae, Acalyphoideae s.s., inaperturate and articulated crotonoids, respectively. Characters of the aril and vascular bundles in the outer integument are discussed. The selected embryological characters were seen to be highly correlated with the molecular phylogeny. When the results of molecular phylogenetic analysis of a previous study and this study were adjusted along with the selected embryological characters, all clades within Euphorbiaceae were supported except for a clade comprising Euphorbioideae + Acalyphoideae s.s. + inaperturate crotonoids + articulated crotonoids + Adenoclineae s.l. and a clade uniting subclades A4–A8 within Acalyphoideae s.s. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Morphological observation,life history and rbcL gene sequence analysis of a new species,Grateloupia variata sp. nov. (Halymeniaceae,Rhodophyta) from Qingdao,China

Grateloupia variata sp. nov. H. W. Wang (Halymeniaceae, Rhodophyta) is newly described from Qingdao, China. The results indicated that: (1) thalli are cartilaginous or gelatinous in texture; (2) thalli are constricted at the base with frequent proliferations; (3) the end portion of branches are irregular, wide, flat or ungulate, split; (4) the cortex is 50–80?μm thick, consisting of four to six layers of cells; the medulla is 10–15?μm long and 1–3?μm wide, consisting of densely and irregularly intertwined filaments; (5) six-celled carpogonial ampullae branched and five-celled auxiliary cell ampullae branched; they are of the typical Grateloupia-type; (6) tetraspores and carpospores grow directly into discoid crusts through initial cell division and are of the immediate discal type; (7) Grateloupia variata sp. nov. shows a typical triphasic life history with homotypic gametophytes, carposporophytes and tetrasporophytes, and a typical homotypic alternation of generations; and (8) the rbcL sequences show no pairwise divergence and the species form a small single monophyletic subclade within the Grateloupia clade. Morphological observations, life history and molecular analysis support G. variata as a new species.     

A COMBINED 18S rDNA AND rbcL PHYLOGENETIC ANALYSIS OF CHLOROMONAS AND CHLAMYDOMONAS (CHLOROPHYCEAE,VOLVOCALES) EMPHASIZING SNOW AND OTHER COLD‐TEMPERATURE HABITATS1

An extensive phylogenetic analysis of the biflagellate genera, Chlamydomonas Ehrenberg and Chloromonas Gobi emend. Wille, was undertaken using 18S rDNA and rbcL gene sequence analysis. Emphasis was placed on 21 cold‐tolerant taxa of which 10 are from snow. These taxa occurred in four distinct clades each in the 18S rDNA and rbcL phylogenies, and when taken together suggest at least five distinct origins in cold habitats. Most of these taxa occur in a single clade (A), and all snow species occurred in this clade. In the rbcL and combined rbcL–18S rDNA analyses, the snow taxa fell into three groups. Two groups occurred in subclade 1: Chlamydomonas augustae Skuja CU, Chlamydomonas augustae UTEX, and Chlamydomonas sp.‐A and Chloromonas clathrata Korshikov, Chloromonas rosae Ettl CU, and Chloromonas rosae v. psychrophila var. nov. The third snow group, subclade 2, included three species with unique cell divisions, Chloromonas brevispina (Fritsch) Hoham, Roemer et Mullet, Chloromonas pichinchae (Lagerheim) Wille, and Chloromonas sp.‐D, and the basal Chloromonas nivalis (Chodat) Hoham et Mullet with normal cell divisions. This suggests that the snow habitat has been colonized at least twice and possibly three times in the history of these biflagellates. In the 18S rDNA tree, one cold‐tolerant Chloromonas species fell outside clade A: Chloromonas subdivisa (Pascher et Jahoda) Gerloff et Ettl. In the rbcL tree, three cold‐tolerant Chloromonas species fell outside clade A: Chloromonas subdivisa, Chloromonas sp.‐ANT1, and Chloromonas sp.‐ANT3. These results support previous findings that pyrenoids have been gained and lost several times within this complex.