Phytochemistry and bioactivity of Acacia sensu stricto (Fabaceae: Mimosoideae)

Phytochemistry Reviews - Acacia sensu lato (Fabaceae: Mimosoideae) was recently retypified and divided into five genera worldwide: Acacia, Acaciella, Mariosousa, Senegalia and Vachellia. Acacia...     

Annotated checklist of Senegalia and Vachellia (Fabaceae: Mimosoideae) for the Indian subcontinent

An annotated checklist of Senegalia Raf. and Vachellia Wight & Arn. taxa for the Indian subcontinent is presented, following the fragmentation and retypification of the former broadly defined genus Acacia Mill. The countries encompassed by this study include Bangladesh, Bhutan, India, Maldives, Nepal, Pakistan and Sri Lanka. All indigenous species (and a few introductions) in this region previously referred to Acacia belong to Senegalia and Vachellia. All Acacia s.s. taxa are introduced (principally from Australia) and are not included in the study. There are 22 species of Senegalia (21 indigenous, 1 introduced; representing 23 taxa) and 21 species of Vachellia (12 indigenous, 9 introduced; representing 27 taxa) currently recognized for the subcontinent. The largest country, India, has most species. This checklist complements that which was recently provided for these genera in southeast Asia and China. Two names formerly recorded for the Indian subcontinent are excluded, namely, Senegalia intsia (L.) Maslin is a nomen confusum and Acacia pennata subsp. hainanensis (Hayata) I. C. Nielsen is now known to be restricted to southern China and Vietnam. Acacia eriantha Desv. is an unresolved name. The following new combinations are made herein: Senegalia tanjorensis (Ragup., Thoth. & A.Mahad.) A.S.Deshpande & Maslin, Vachellia campbellii (Arn.) A.S.Deshp., & Maslin and V. pseudowightii (Thoth.) A.S.Deshpande & Maslin. A lectotype has been selected for Acacia pennata var. canescens Graham ex Kurz (= Senegalia pennata (L.) Maslin).     

Australian Thysanoptera – biological diversity and a diversity of studies

Abstract   Studies in Australia on thrips have had extensive impacts worldwide. In behaviour, the latest definition of eusociality is derived from work on the radiation of thrips on Acacia species in central Australia, and these Acacia thrips also having been used to develop the concept of 'model clades' for analysing the evolution of behavioural and ecological diversity. In ecology, the concept of the lack of density dependent factors in population dynamics was elaborated through studies on the plague thrips of southern Australia. In virology, thrips were first shown in Australia to be the vectors of tospoviruses, although these viruses, their vectors and the plants attacked are all non-native to this continent. Work in Australia has included the development of electronic methods of illustration, identification and information transfer about thrips, including the use of molecular methods for pest species recognition, and considerable advances have been made in Australia in our knowledge of the relationships between thrips and plants, from polyphagy to pollination.     

Origin,Differentiation, and Geographic Distribution of the Chenopodiaceae

Numbers of species and genera,endemic genera,extant primitive genera,relationship and distribution patterns of presently living Chenopodiaceae(two subfamilies,12 tribes,and 118 genera)are analyzed and compared for eight distributional areas,namely central Asia,Europe,the Mediterranean region,Africa,North America,South America, Australia and East Asia． The Central Asia,where the number of genera and diversity of taxa are greater than in other areas,appears to be the center of distribution of extant Chenopodiaceae．North America and Australia are two secondary centers of distribution． Eurasia has 11 tribes out of the 12,a total of 70 genera of extant chenopodiaceous plants,and it contains the most primitive genera of every tribe． Archiatriplex of Atripliceae,Hablitzia of Hablitzeae,Corispermum of Corispermeae,Camphorosma of Camphorosmaea,Kalidium of Salicornieae,Polecnemum of Polycnemeae,Alexandra of Suaedeae,and Nanophyton of Salsoleae,are all found in Eurasia,The Beteae is an Eurasian endemic tribe,demonstrating the antiquity of the Chenopodiaceae flora of Eurasia．Hence,Eurasia is likely the place of origin of chenopodiaceous plants． The presence of chenopodiaceous plants is correlated with an arid climate．During the Cretaceous Period,most places of the continent of Eurasia were occupied by the ancient precursor to the Mediterranean,the Tethys Sea．At that time the area of the Tethys Sea had a dry and warm climate．Therefore,primitive Chenopodiaceae were likely present on the beaches of this ancient land．This arid climatic condition resulted in differentiation of the tribes Chenopodieae,Atripliceae,Comphorosmeae,Salicornieae,etc．,the main primitive tribes of the subfamily Cyclolobeae. Then following continental drift and the Laurasian and Gondwanan disintegration, the Chenopodiaceae were brought to every continent to propagate and develop, and experience the vicissitudes of climates, forming the main characteristics and distribution patterns of recent continental floras. The tribes Atripliceae, Chenopodieae, Camphorosmeae, and Salicornieae of recent Chenopodiaceae in Eurasia, North America, South America, southern Africa, and Australia all became strongly differentiated. However, Australia and South America, have no genera of Spirolobeae except for a few maritime Suaeda species. The Salsoleae and Suaedeae have not arrived in Australia and South America, which indicates that the subfamily Spirolobeae developed in Eurasia after Australia separated from the ancient South America-Africa continent, and South America had left Africa. The endemic tribe of North America, the tribe Sarcobateae, has a origin different from the tribes Salsoleae and Suaedeae of the subfamily Spirolobeae. Sarcobateae flowers diverged into unisexuality and absence of bractlets. Clearly they originated in North America after North America had left the Eurasian continent. North America and southern Africa have a few species of Salsola, but none of them have become very much differentiated or developed, so they must have arrived through overland migration across ancient continental connections. India has no southern African Chenopodiaceae floristic components except for a few maritime taxa, which shows that when the Indian subcontinent left Africa in the Triassic period, the Chenopodiaceae had not yet developed in Africa. Therefore, the early Cretaceous Period about 120 million years ago, when the ancient Gondwanan and Laurasian continents disintegrated, could have been the time of origin of Chenopodiaceae plants.The Chinese flora of Chenopodiaceae is a part of Chenopodiaceae flora of central Asia. Cornulaca alaschnica was discovered from Gansu, China, showing that the Chinese Chenopodiaceae flora certainly has contact with the Mediterranean Chenopodiaceae flora. The contact of southeastern China with the Australia Chenopodiaceae flora, however, is very weak.     

Reserve mass and dispersal investment in relation to geographic range of plant species: phylogenetically independent contrasts

Recent studies have reported conflicting evidence about correlations between seed size and plant species geographic range sizes. Using phylogenetically independent contrasts (PICs) within genera, we found no consistent differences in reserve mass between species with similar dispersal morphology and «wide>> versus «narrow>> geographic ranges. There was also no tendency within genera for broad ranged species to be those that allocate a larger percentage of the resources invested in each diaspora to dispersal structures. PICs were also constructed between species having a tenfold difference in seed size. In these PICs, the larger seeded species often occupied a greater number of regions than species with smaller seed sizes. This result was generated primarily through the comparison of species from different genera, families or higher level taxa which differed not only in seed mass but also in dispersal modes and growth forms. Finally, comparing species within Acacia and Eucalyptus having similar seed size but different dispersal modes, we found that bird dispersal (in Acacia ) and possession of a wing for wind dispersal (in Eucalyptus ) was associated with wider geographic range compared to lower-investment dispersal modes. Taken together, these comparisons indicate that seed size is not itself important as a factor influencing breadth of geographic range. Dispersal mode and growth form may have an influence, however, and seed size differences may be associated with contrasts in dispersal mode or growth form.     

New stygobiont copepods (Calanoida; Misophrioida) from Bundera Sinkhole, an anchialine cenote in north-western Australia

Two new taxa in the copepod orders Calanoida and Misophrioida are described from the flooded coastal karst of north-western Australia. Stygocyclopia australis sp. nov. is the first pseudocyclopiid calanoid to be reported from the continent, with other congeners distributed in anchialine environments of the Philippine, Balearic, and Canary archipelagos. The presence of a supernumerary spine on the outer margin of the first exopod segment of leg 3 in this species is discussed in the context of the Neocopepodan groundpattern. Speleophria bunderae sp. nov. is the first representative of the order Misophrioida known from Australia, with other congeners in the Balearics, Bermuda, and the Yucatan peninsula of México. Both taxa co-exist in the deeper higher salinity layers of a single sinkhole in Cape Range peninsula. The placement of these taxa in strictly stygobiont genera represented by very localized and disjunct species distributed over regions flooded by the late Mesozoic seas, lends support to their interpretation as true Tethyan relicts, and hence to the inclusion in the past of the Northwest portion of Australia in the Tethyan realm. The remains of S. bunderae in the gut contents of a stygobiont epacteriscid calanoid is recorded.     

藜科植物的起源、分化和地理分布

全球藜科植物共约130属1500余种,广泛分布于欧亚大陆、南北美洲、非洲和大洋洲的半干旱及盐碱地区。它基本上是一个温带科,对亚热带和寒温带也有一定的适应性。本文分析了该科包含的1l族的系统位置和分布式样,以及各个属的分布区,提出中亚区是现存藜科植物的分布中心,原始的藜科植物在古地中海的东岸即华夏陆台(或中国的西南部)发生,然后向干旱的古地中海沿岸迁移、分化,产生了环胚亚科主要族的原始类群;起源的时间可能在白垩纪初,冈瓦纳古陆和劳亚古陆进一步解体的时期。文章对其迁移途径及现代分布式样形成的原因进行了讨论。     

Molecular phylogenetics of Acacia (Fabaceae: Mimosoideae) based on the chloroplast MATK coding sequence and flanking TRNK intron spacer regions

The tribe Acacieae (Fabaceae: Mimosoideae) contains two genera, the monotypic African Faidherbia and the pantropical Acacia, which comprise about 1200 species with over 950 confined to Australia. As currently recognized, the genus Acacia is subdivided into three subgenera: subg. Acacia, subg. Aculeiferum, and the predominantly Australian subg. Phyllodineae. Morphological studies have suggested the tribe Acacieae and genus Acacia are artificial and have a close affinity to the tribe Ingeae. Based on available data there is no consensus on whether Acacia should be subdivided. Sequence analysis of the chloroplast trnK intron, including the matK coding region and flanking noncoding regions, indicate that neither the tribe Acacieae nor the genus Acacia are monophyletic. Two subgenera are monophyletic; section Filicinae of subgenus Aculeiferum does not group with taxa of the subgenus. Section Filicinae, eight Ingeae genera, and Faidherbia form a weakly supported paraphyletic grade with respect to subg. Phyllodineae. Acacia subg. Aculeiferum (s. s.) is sister to the grade. These data suggest that characters currently used to differentiate taxa at the tribal, generic, and subgeneric levels are polymorphic and homoplasious in cladistic analyses.     

Multiple gene sequences delimit Botryosphaeria australis sp. nov. from B. lutea

Botryosphaeria lutea (anamorph Fusicoccum luteum) most easily is distinguished from other Botryosphaeria spp. by a yellow pigment that is formed in young cultures. This fungus has been reported from a number of cultivated hosts in New Zealand and Portugal. During a survey of Botryosphaeria fungi that occur on native Acacia species in Australia, a yellow pigment was observed in some cultures. These isolates were morphologically similar to B. lutea, but the pigment differed slightly from the one formed by authentic B. lutea isolates. Preliminary data also revealed small differences in ITS rDNA sequence data. The aim of this study was to determine whether these small differences were indicative of separate species or merely variations within B. lutea. Anamorph, teleomorph and culture morphology were compared between B. lutea and Acacia isolates from Australia. Sequence data of two other genome regions, namely the β-tubulin and EF1-α gene and intron regions, were combined with ITS rDNA sequence data to determine the phylogenetic relationship between these isolates. Isolates of B. lutea and those from Australian Acacia species were not significantly different in spore morphology. The yellow pigment, however, was much more distinct in cultures of B. lutea than in cultures from Acacia. There were only a few base pair variations in each of the analyzed gene regions, but these variations were fixed in the two groups in all regions. By combining these data it was clear that B. lutea and the isolates from Acacia were distinct species, albeit very closely related. We, therefore, propose the new epithet B. australis for the fungus from Australia. Botryosphaeria australis also was isolated in this study from exotic Sequoiadendron trees in Australia. Re-analyses of GenBank data in this study showed that B. australis also occurs on other native Australian hosts, namely a Banksia sp. and a Eucalyptus sp., as well as a native Protea sp. in South Africa and on Pistachio in Italy. These records from GenBank have been identified previously as B. lutea. The common occurrence of B. australis on a variety of native hosts across Australia suggests that this fungus is native to this area.     

Implications of the changing phylogenetic relationships of Acacia s.l. on the biological control of Vachellia nilotica ssp. indica in Australia

Plant relationships have implications for many fields including weed biological control. The use of DNA sequencing and new tree building algorithms since the late 1980s and early 1990s have revolutionised plant classification and has resulted in many changes to previously accepted taxonomic relationships. It is critical that biological control researchers stay abreast of changes to plant phylogenies. One of the largest plant genera, Acacia, has undergone great change over the past 20 years and these changes have ramifications for weed biological control projects in a number of countries. Vachellia nilotica (prickly acacia) is a major weed in Australia, originating from the Indian subcontinent and Asia, and it has been a target for biological control since 1980. Once a member of Acacia, a large (>1,000 spp.) and iconic group in Australia, prickly acacia is now part of the genus Vachellia. Current knowledge suggests that Vachellia is more closely related to mimosoid genera than it is to Acacia s.s. There has also been a recent reclassification of legume subfamilies with subfamily Mimosoideae now part of subfamily Caesalpinioideae, and four new subfamilies. In this paper we review the changes that have occurred to this group since the prickly acacia biological control project began and discuss the implications for the project. A new host test list for quarantine testing is proposed. Developed following the modernisation of the centrifugal‐phylogenetic method, it is shorter than past lists, containing 46 species, although still lengthy because of the expectations of regulatory bodies, which are slower to accept advances in scientific knowledge. The list includes five Vachellia species, six “Mimoseae” species and 26 Acacia species. The number species from legume subfamilies other than the new Caesalpinioideae is greatly reduced.     

Molecular phylogeny and zoogeography of the freshwater crayfish genus Cherax Erichson (Decapoda: Parastacidae) in Australia

The evolutionary history and biogeography of freshwater-dependent taxa in Australia is of intrinsic interest given the present-day aridity of this continent. Cherax is the most widespread and one of the most species-rich of Australia's nine freshwater crayfish genera. The phylogenetic relationships amongst 19 of the 23 Australian Cherax were established from mitochondrial DNA sequences representing the 12S rRNA and 16S rRNA gene regions. The relationships among species support an initial east–west separation, followed by a north–south divergence in eastern Australia. Molecular clock estimations suggest that these divergences date back to the Miocene. The phylogenetic relationships support endemic speciation within geographical regions and indicate that long-distance dispersal has not led to recent speciation as previously hypothesized. This new evolutionary scenario is consistent with the climatic history of Australia and the evolutionary history of other similarly distributed freshwater-dependent organisms in Australia.  © 2004 The Linnean Society of London, Biological Journal of the Linnean Society , 2004, 81 , 553–563.     

Differences in life‐cycle stage components between native and introduced ranges of five woody Fabaceae species

Understanding differences in the components of life‐cycle stages of species between their native and introduced ranges can provide insights into the process of species transitioning from introduction to naturalization and invasion. We examined reproductive variables of the germination (seed predation, seed viability, time to germination), seed output (crown projection, seed production, seed weight) and dispersal (seed weight, dispersal investment) stages of five woody Fabaceae species, comparing native and introduced ranges. We predicted that each species would differ in reproductive variables of at least one life‐cycle stage between their native and introduced ranges, thus allowing us to determine the life‐cycle stage most associated with invasion success in the introduced range. Acacia melanoxylon and Paraserianthes lophantha had reduced seed predation in their introduced ranges while P. lophantha also had higher seed viability indicating that the germination life‐cycle stage is most strongly associated with their invasion success in the introduced range. Only Acacia longifolia varied between ranges for the seed output stage due to larger plant size, greater seed production and smaller seed size in its introduced range. Similar to A. longifolia, Acacia cyclops had smaller seed size in its introduced range but did not have any other variable differences between ranges suggesting that the dispersal stage is best associated with its invasion success in the introduced range. Surprisingly, Acacia saligna was the only species without a clear life‐cycle stage difference between ranges despite it being one of the more invasive acacia species in Australia. Although we found clear differences in reproductive variables associated with life‐cycle stages between native and introduced ranges of these five species, these differences were largely species‐specific. This suggests that a species invasion strategy into a novel environment is complex and varies among species depending on the environmental context, phenotypic plasticity and genotypic variation in particular traits.     

Evolution and loss of long-fringed petals: a case study using a dated phylogeny of the snake gourds, Trichosanthes (Cucurbitaceae)

ABSTRACT: BACKGROUND: The Cucurbitaceae genus Trichosanthes comprises 90-100 species that occur from India to Japan and southeast to Australia and Fiji. Most species have large white or pale yellow petals with conspicuously fringed margins, the fringes sometimes several cm long. Pollination is usually by hawkmoths. Previous molecular data for a small number of species suggested that a monophyletic Trichosanthes might include the Asian genera Gymnopetalum (four species, lacking long petal fringes) and Hodgsonia (two species with petals fringed). Here we test these groups' relationships using a species sampling of c. 60% and 4759 nucleotides of nuclear and plastid DNA. To infer the time and direction of the geographic expansion of the Trichosanthes clade we employ molecular clock dating and statistical biogeographic reconstruction, and we also address the gain or loss of petal fringes. RESULTS: Trichosanthes is monophyletic as long as it includes Gymnopetalum, which itself is polyphyletic. The closest relative of Trichosanthes appears to be the sponge gourds, Luffa, while Hodgsonia is more distantly related. Of six morphology-based sections in Trichosanthes with more than one species, three are supported by the molecular results; two new sections appear warranted. Molecular dating and biogeographic analyses suggest an Oligocene origin of Trichosanthes in Eurasia or East Asia, followed by diversification and spread throughout the Malesian biogeographic region and into the Australian continent. CONCLUSIONS: Long-fringed corollas evolved independently in Hodgsonia and Trichosanthes, followed by two losses in the latter coincident with shifts to other pollinators but not with long-distance dispersal events. Together with the Caribbean Linnaeosicyos, the Madagascan Ampelosicyos and the tropical African Telfairia, these cucurbit lineages represent an ideal system for more detailed studies of the evolution and function of petal fringes in plant-pollinator mutualisms.     

Morphological and Functional Divergence of the Lower Jaw Between Native and Invasive Red Foxes

Journal of Mammalian Evolution - The introduction of European red foxes in Australia in the late mid-nineteenth century has resulted in the spread of this invasive species across the continent. The...     

Frugivore gape size and the evolution of fruit size and shape in southern hemisphere floras

Abstract The present study uses differences among frugivore faunas of the southern hemisphere landmasses to test whether frugivore characteristics have influenced the evolution of fruit traits. Strong floristic similarities exist among southern landmasses; for example, 75% of New Zealand vascular plant genera also have species in Australia. However, plants in Australia and South America have evolved in the presence of a range of mammalian frugivores, whereas those in New Zealand, New Caledonia and the Pacific Islands have not. In addition, the avian frugivores in New Zealand and New Caledonia are generally smaller than those of Australia. If frugivore characteristics have influenced the evolution of fruit traits, predictable differences should exist between southern hemisphere fruits, particularly fruit size and shape. Fruit dimensions were measured for 77 New Zealand species and 31 Australian species in trans‐Tasman genera. New Zealand fruits became significantly more ellipsoid in shape with increasing size. This is consistent with frugivore gape size imposing a selective pressure on fruit ingestability. This result is not a product of phylogenetic correlates, as fruit length and width scaled isometrically for Australian species in genera shared with New Zealand. Within‐genus contrasts between New Zealand and Australian species in 20 trans‐Tasman genera showed that New Zealand species have significantly smaller fruits than their Australian counterparts. Within‐genus contrasts between New Zealand and South American species in nine genera gave the same result; New Zealand species had significantly smaller fruits than their South American counterparts. No difference was found in fruit size or shape between New Zealand and New Caledonia congeneric species from 12 genera. These results are consistent with the broad characteristics of the frugivore assemblage influencing the evolution of fruit size and shape in related species. The smaller‐sized New Zealand frugivore assemblage has apparently influenced the evolution of fruit size of colonizing taxa sometimes within a relatively short evolutionary timeframe.     

Cyanobacterial composition of microbial mats from an Australian thermal spring: a polyphasic evaluation

Cyanobacterial composition of microbial mats from an alkaline thermal spring issuing at 43-71 degrees C from tropical north-eastern Australia are described using a polyphasic approach. Eight genera and 10 species from three cyanobacterial orders were identified based on morphological characters. These represented taxa previously known as thermophilic from other continents. Ultrastructural analysis of the tower mats revealed two filamentous morphotypes contributed the majority of the biomass. Both types had ultrastructural characteristics of the family Pseudanabaenaceae. DNA extracts were made from sections of the tentaculiform towers and the microbial community analysed by 16S cyanobacteria-specific PCR and denaturing-gradient gel electrophoresis. Five significant bands were identified and sequenced. Two bands clustered closely with Oscillatoria amphigranulata isolated from New Zealand hot springs; one unique phylotype had only moderate similarity to a range of Leptolyngbya species; and one phylotype was closely related to a number of Geitlerinema species. Generally the approaches yielded complementary information, however the results suggest that species designation based on morphological and ultrastructural criteria alone often fails to recognize their true phylogenetic position. Conversely some molecular techniques may fail to detect rare taxa suggesting that the widest possible suite of techniques be applied when conducting analyses of cyanobacterial diversity of natural populations. This is the first polyphasic evaluation of thermophilic cyanobacterial communities from the Australian continent.     

Australian hookworms (Ancylostomatoidea): a review of the species present,their distributions and biogeographical origins

Ancylostomatoidea or hookworms recorded in Australia are reviewed and the attempt is made to provide the biogeographical background to their occurrence. The poor representation of this nematode superfamily is probably a reflection of the fact that they are primarily parasites of Carnivora, Artiodactyla, Insectivora, Rodentia, Edentata, Proboscoidea and primates, eutherian mammals which are either absent from the Australian fauna or which have only recently reached the continent. The principal genera of hookworms recorded to date from Australia are Ancylostoma, Bunostomum, Necator and Uncinaria. The majority of the ancylostomatoid fauna is represented by introduced species of man and domestic animals. Native or endemic species of hookworms are restricted to members of the genus Uncinaria with two species occurring in rodents and pinnipeds. Only a single endemic species of hookworm is known, U. hydromyidis, which is found in the small intestine of a rat. Significant problems remain in understanding the systematics, epidemiology and evolutionary relationships of the Australian ancylostomatoid fauna.     

Spatial variation in egg polymorphism among cuckoo hosts across 4 continents

Although egg color polymorphism has evolved as an effective defensive adaptation to brood parasitism, spatial variations in egg color polymorphism remain poorly characterized. Here, we investigated egg polymorphism in 647 host species (68 families and 231 genera) parasitized by 41 species of Old Word cuckoos (1 family and 11 genera) across Asia, Europe, Africa, and Australia. The diversity of parasitic cuckoos differs among continents, reflecting the continent-specific intensities of parasitic selection pressure on hosts. Therefore, host egg polymorphism is expected to evolve more frequently on continents with higher cuckoo diversity. We identified egg polymorphism in 24.1% of all host species and 47.6% of all host families. The common cuckoo Cuculus canorus utilized 184 hosts (28.4% of all host species). Hosts of the common cuckoo and of Chrysococcyx species were more likely to have polymorphic eggs than hosts parasitized by other cuckoos. Both the number of host species and the host families targeted by the cuckoo species were positively correlated with the frequency of host egg polymorphism. Most host species and most hosts exhibiting egg color polymorphism were located in Asia and Africa. Host egg polymorphism was observed less frequently in Australia and Europe. Our results also suggested that egg polymorphism tends to occur more frequently in hosts that are utilized by several cuckoo species or by generalist cuckoo species. We suggest that selection pressure on hosts from a given continent increases proportionally to the number of cuckoo species, and that this selection pressure may, in turn, favor the evolution of host egg polymorphism.     

金粟兰科的起源,演化及其分布

本文利用形态解剖,孢粉学及化石资料,讨论了金粟兰科的系统;并对其起源,演化和现代分布格局形成等问题做了合理推测,主要结果如下：（１）Ｓａｒｃａｎｄｒａ和Ｃｈｌｏｒａｎｔｈｕｓ的亲缘关系最接近,而Ａｓｃａｒｉｎａ和Ｈｅｄｙｏｓｍｕｍ的系统位置最靠近。Ｓａｒｃａｎｄｒａ是金粟兰科中最原始的属,而Ｈｅｄｙｏｓｍｕｍ则是最进化的属。（２）金粟兰科可能于白垩纪最早期起源于木质部无导管的,具简单两性虫媒花的祖     

Beyond the prolegomenon: a molecular phylogeny of the Australian camaenid land snail radiation

From an analysis of over 900 specimens of camaenid land snails, we have assembled a molecular phylogeny of 327 tips covering > 70% genera across the entire continent of Australia and including > 90% of eastern species. Our approach emphasizes sampling to identify lineage flocks from populations down to build a hierarchical gene‐by‐taxa tapestry or supermatrix dataset using three mitochondrial genes, then analysed with Markov chain Monte Carlo and fast maximum likelihood methods. Similarity amongst taxa set results suggests missing data cause only minor distortions. This is supplemented by a separate higher level 28S rDNA phylogeny for a global scale perspective. The shallow divergence of Australasian forms, and their nesting within South‐East Asian groups within the Helicoidea supergroup extending from Europe to North America, is consistent with the Solem hypothesis of Laurasian immigration of c. Miocene origin, and so being more than 400 species in 80‐plus genera spread across the continent of Australia from rainforest to desert, forms an immense radiation. There is a major distinction between eastern and western lineages, with some key exceptions. Finer scale patterns of relictual endemics indicate that many ancestral lineages were in place before the major decline and breakup of the Tertiary mesic forest realm that once dominated Gondwanan Australia, and so chart the phylogenetic turnover of ecosystem change from mesic to xeric. The various higher classification schemes proposed all founder on the sheer scale of this radiation. Of 30 polytypic genera tested, at least 18 are not monophyletic, highlighting (1) the repeated radiation of shell forms, and (2) that the current higher taxonomy is unacceptable. Here we provide a phylogenetic and biogeographically condign arrangement as the basis for future elaborations. © 2011 The Linnean Society of London, Zoological Journal of the Linnean Society, 2011, 161 , 531–572.