Relict Lineage Research Articles

Endemic evolutionary radiation of Rhagada land snails (Pulmonata: Camaenidae) in a continental archipelago in northern Western Australia

In the Dampier Archipelago of Western Australia's Pilbara Region, several locally endemic, morphologically distinctive species of Rhagada land snails occur, contrasting with the morphologically conservative species with wider distributions on the adjacent mainland. To test alternative origins of this unusual local diversity in a continental archipelago, we examined sequences of the cytochrome oxidase subunit 1 and 16S mitochondrial genes in 22 described species and eight undescribed forms, including all known morphospecies from the Pilbara Region's Dampier Archipelago and adjacent mainland. Phylogenetic analyses consistently resolved four, deep clades within the Pilbara Region, with a mean sequence divergence of 15–18%. All but one of the species from the Dampier Archipelago formed one of the major clades, indicating that the morphological radiation in the archipelago evolved locally, rather than through multiple, relictual mainland lineages. Morphological divergence spanning almost that of the entire genus was within a subclade with sequence divergence < 4%, highlighting the disconnection between morphological diversification and levels of molecular genetic divergence. This in situ morphological radiation in the Dampier Archipelago, which transcends variation seen over much larger distances on the mainland, is unusual for a continental archipelago, and may relate to local heterogeneity of land forms. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 106, 316–327.

A termite from the Late Oligocene of northern Ethiopia

Termites of the family Stolotermitidae are a relict lineage of primitive Isoptera. The fossil record of Stolotermitidae is exceptionally poor, with only two Miocene (Neogene) species documented to date. Herein, a new genus and species of Paleogene termites is described and figured from the Late Oligocene (28-27 Ma, Early Chattian) of northwestern Ethiopia (Amhara Region, Chilga Woreda). Chilgatermes diamatensis gen. et sp. nov., is most similar to genera of the Stolotermitidae, Archotermopsidae, and Termopsidae but can be distinguished on the basis of forewing venational details. The genus is tentatively placed in the Stolotermitidae: Porotermitinae. Chilgatermes diamatensis is the first fossil termite from Ethiopia and, indeed, the first from the entire African continent.

China: home for the most endangered plants of the world?

If you ask to a western botanist: “Which is the world’s most endangered plant species?” he will probably answer the Florida torreya (Torreya taxifolia Arn.), the Wollemi pine (Wollemia nobilis W. G. Jones, K. D. Hill & J. M. Allen), or perhaps the Nebrodi fir (Abies nebrodensis Mattei), if the interviewed is of european origin. In contrast, if you make the same question to a Chinese (or at least to somebody familiar with the Chinese flora) you may get a quite different reply. Much less known than these emblematic trees, a large handful of Chinese plant taxa is currently in a more critical situation, with just a very few individuals surviving (He, 2009; Lopez-pujol & zhang, 2009). A rare cypress (Cupressus chengiana S. Y. Hu var. jiangeensis (N. zhao) Silba1) is arguably the most threatened gymnosperm on earth because only one individual tree occurs in Longmen (“Dragon’s Gate”) Mountains, in northern Sichuan. The baishanzu fir (Abies beshanzuensis M. H. Wu var. beshanzuensis1) from zhejiang, is not in a much wealthier situation, with only three representatives alive. Moreover, China has also the dubious honour of harbouring some of the surely world’s most endangered angiosperms, such as Carpinus putoensis W. C. Cheng (one fenced, old individual is remaining in the wild in putuo Island, in the east China Sea), Gleditsia japonica Miq. var. velutina L. Chu Li1 and Sinopora hongkongensis (N. H. Xia, Y. F. Deng & K. L.Yip) J. Li, N. H. Xia & H. W. Li (with two individuals each one), or Acer yangbiense Y. S. Chen & Q. e. Yang (with four representatives). These few conspicuous examples of rare plants, however, may represent just the iceberg’s tip of a flora facing a situation of extreme risk: of the approximately 4200 angiosperm taxa assessed in the first issue of the China Species Red List (which represents just 14% of the angiosperm flora of China), as many as 651 were listed as CR (“critically endangered”) following the 2001 IuCN criteria (Xie & Wang, 2007), that is, in the verge of extinction. The disproportionate number of extremely threatened plants in China may have resulted from the combination of natural and human-induced factors (Lopez-pujol & zhang, 2009). The existence of numerous refuge areas during the Quaternary glacial periods in China (Qian & Ricklefs, 2000; Lopezpujol, 2008; Lopez-pujol & Ren, 2010) yielded a large number of narrow endemics through survival of relict (pre-Quaternary) lineages as well as by differentiation and speciation in these favourable pockets, most of them located in the southern mountainous regions (Fig. 1). The huge destruction and deterioration of ecosystems, largely reported in China during recent decades (e.g. Lopez-pujol et al., 2006; He, 2009), must have decimated many of these “naturally rare” species, in some cases driving them to the brink of extinction (such as the abovementioned examples) or

Molecular phylogeny of Atripliceae (Chenopodioideae, Chenopodiaceae): Implications for systematics, biogeography, flower and fruit evolution, and the origin of C4 photosynthesis

Atripliceae (Chenopodiaceae), including Atriplex (300 spp.) as the largest genus of the family, are an ecologically important group of steppes and semideserts worldwide. Relationships in Atripliceae are poorly understood due to obscure and potentially convergent morphological characters. • Using sequence variation of two chloroplast markers (rbcL gene, atpB-rbcL spacer) and one nrDNA marker (ITS) analyzed with BEAST, we investigated the systematics and biogeography of Atripliceae. We surveyed flower morphology and fruit anatomy to study the evolution of flowers and fruits in the tribe. • Female flowers with persistent foliar cover (the diagnostic character of traditional Atripliceae) evolved three times in Chenopodioideae, in Atripliceae s.s., Axyrideae, and Spinacia. Atripliceae s.s. started to diversify during the Early Miocene in Eurasia, separating into the Archiatriplex and the Atriplex clades. The former consists of eight species-poor, disjunct, and morphologically heterogeneous genera and is likely a relictual lineage. The Atriplex clade comprises the majority of species and evolved one C(4) lineage 14.1-10.5 Ma, which diversified rapidly worldwide. The C(4) Atriplex entered North America during the Middle/Late Miocene and spread to South America subsequently. Australia was colonized by two C(4) lineages both arriving during the Late Miocene. One of them diversified rapidly, giving rise to most Australian Atriplex species. • Atripliceae s.s. comprise Archiatriplex, Atriplex, Exomis, Extriplex, Grayia, Halimione, Holmbergia, Manochlamys, Proatriplex, and Stutzia. Microgynoecium is included based on morphology but only weak molecular support. Axyris, Krascheninnikovia, and Ceratocarpus (here described as Axyrideae) and Spinacia are excluded from Atripliceae.

Phylogeny and biogeography of the Asian trogons (Aves: Trogoniformes) inferred from nuclear and mitochondrial DNA sequences

We present the first species-level molecular phylogenetic hypothesis for the Asian trogons, using DNA sequences of multiple mitochondrial and nuclear loci, and Bayesian and maximum likelihood tree reconstruction methods. The two genera of Asian trogons, Harpactes and Apalharpactes, are distantly related to each other. Within the widespread Southeast Asian genus Harpactes, we recovered three species groups: (1) H. oreskios; (2) H. orrhophaeus and H. duvaucelii; and (3) a clade of the seven large-bodied species. Short internal branch lengths link species in the large-bodied group, suggesting rapid diversification. Apalharpactes, which is currently restricted to the montane forests of Sumatra and Java, appears to be a relictual lineage distantly related to all other trogons. Bayesian and maximum likelihood analyses indicate Apalharpactes is sister to the African genus Apaloderma, although this result was not strongly supported. Overall, the extant Asian trogon species appear to have diversified prior to the Pleistocene, based on large pair-wise mitochondrial divergences between taxa.

The Trichoderma harzianum demon: complex speciation history resulting in coexistence of hypothetical biological species, recent agamospecies and numerous relict lineages.

BackgroundThe mitosporic fungus Trichoderma harzianum (Hypocrea, Ascomycota, Hypocreales, Hypocreaceae) is an ubiquitous species in the environment with some strains commercially exploited for the biological control of plant pathogenic fungi. Although T. harzianum is asexual (or anamorphic), its sexual stage (or teleomorph) has been described as Hypocrea lixii. Since recombination would be an important issue for the efficacy of an agent of the biological control in the field, we investigated the phylogenetic structure of the species.ResultsUsing DNA sequence data from three unlinked loci for each of 93 strains collected worldwide, we detected a complex speciation process revealing overlapping reproductively isolated biological species, recent agamospecies and numerous relict lineages with unresolved phylogenetic positions. Genealogical concordance and recombination analyses confirm the existence of two genetically isolated agamospecies including T. harzianum sensu stricto and two hypothetical holomorphic species related to but different from H. lixii. The exact phylogenetic position of the majority of strains was not resolved and therefore attributed to a diverse network of recombining strains conventionally called 'pseudoharzianum matrix'. Since H. lixii and T. harzianum are evidently genetically isolated, the anamorph - teleomorph combination comprising H. lixii/T. harzianum in one holomorph must be rejected in favor of two separate species.ConclusionsOur data illustrate a complex speciation within H. lixii - T. harzianum species group, which is based on coexistence and interaction of organisms with different evolutionary histories and on the absence of strict genetic borders between them.

Out of the Palaeotropics? Historical biogeography and diversification of the cosmopolitan ectomycorrhizal mushroom family Inocybaceae

AbstractAim The ectomycorrhizal (ECM) mushroom family Inocybaceae is widespread in north temperate regions, but more than 150 species are encountered in the tropics and the Southern Hemisphere. The relative roles of recent and ancient biogeographical processes, relationships with plant hosts, and the timing of divergences that have shaped the current geographic distribution of the family are investigated.Location Africa, Australia, Neotropics, New Zealand, north temperate zone, Palaeotropics, Southeast Asia, South America, south temperate zone.Methods We reconstruct a phylogeny of the Inocybaceae with a geological timeline using a relaxed molecular clock. Divergence dates of lineages are estimated statistically to test vicariance‐based hypotheses concerning relatedness of disjunct ECM taxa. A series of internal maximum time constraints is used to evaluate two different calibrations. Ancestral state reconstruction is used to infer ancestral areas and ancestral plant partners of the family.Results The Palaeotropics are unique in containing representatives of all major clades of Inocybaceae. Six of the seven major clades diversified initially during the Cretaceous, with subsequent radiations probably during the early Palaeogene. Vicariance patterns cannot be rejected that involve area relationships for Africa–Australia, Africa–India and southern South America–Australia. Northern and southern South America, Australia and New Zealand are primarily the recipients of immigrant taxa during the Palaeogene or later. Angiosperms were the earliest hosts of Inocybaceae. Transitions to conifers probably occurred no earlier than 65 Ma.Main conclusions The Inocybaceae initially diversified no later than the Cretaceous in Palaeotropical settings, in association with angiosperms. Diversification within major clades of the family accelerated during the Palaeogene in north and south temperate regions, whereas several relictual lineages persisted in the tropics. Both vicariance and dispersal patterns are detected. Species from Neotropical and south temperate regions are largely derived from immigrant ancestors from north temperate or Palaeotropical regions. Transitions to conifer hosts occurred later, probably during the Palaeogene.

An overlooked pink species of land iguana in the Galápagos

Despite the attention given to them, the Galápagos have not yet finished offering evolutionary novelties. When Darwin visited the Galápagos, he observed both marine (Amblyrhynchus) and land (Conolophus) iguanas but did not encounter a rare pink black-striped land iguana (herein referred to as "rosada," meaning "pink" in Spanish), which, surprisingly, remained unseen until 1986. Here, we show that substantial genetic isolation exists between the rosada and syntopic yellow forms and that the rosada is basal to extant taxonomically recognized Galápagos land iguanas. The rosada, whose present distribution is a conundrum, is a relict lineage whose origin dates back to a period when at least some of the present-day islands had not yet formed. So far, this species is the only evidence of ancient diversification along the Galápagos land iguana lineage and documents one of the oldest events of divergence ever recorded in the Galápagos. Conservation efforts are needed to prevent this form, identified by us as a good species, from extinction.

A new genus and species of characid fish from the Amazon basin: the recognition of a relictual lineage of characid fishes (Ostariophysi: Cheirodontinae: Cheirodontini)

Amazonspinther dalmata, a new miniature characid from the streams of rio Purus and rio Madeira, right bank tributaries of the rio Amazonas, is described as a new genus and species of the subfamily Cheirodontinae. The unique characters of the new genus and species are the three remarkable black blotches on the base of the dorsal, anal, and caudal fins, the anteriormost proximal radial of the anal fin with an anteriorly extended lamina entering the abdominal cavity, and the extremely elongate caudal peduncle. The reduced number of ventral procurrent caudal-fin rays (7-9), and the hemal spines of only posterior one, two, or sometimes three caudal vertebrae directly articulating with the ventral procurrent caudal-fin rays further diagnoses the new taxon from remaining genera of the tribe Cheirodontini. The results of a phylogenetic analysis strongly support a close relationship between A. dalmata and Spintherobolus in the tribe Cheirodontini on the basis of fifteen unambiguous synapomorphies. Ten of these characters, previously hypothesized as exclusive synapomorphies for Spintherobolus, were now also identified in Amazonspinther, such as the pattern of exposed neuromasts on the head, the presence of a second pseudotympanum anterior to the first pleural rib, and the nearly discoidal coracoid bone. A discussion about the phylogenetic position of the closely related fossil †Megacheirodon to Spintherobolus and Amazonspinther is also provided. Convergent characters shared between Amazonspinther and the characid Priocharax are discussed in relation to miniaturization. Biogeographical implications of the diversification of Amazonspinther, Spintherobolus, and Megacheirodon lineages are discussed.

Global diversity of dobsonflies, fishflies, and alderflies (Megaloptera; Insecta) and spongillaflies, nevrorthids, and osmylids (Neuroptera; Insecta) in freshwater

The insect orders Megaloptera and Neuroptera are closely related members of the superorder Neuropterida, a relict lineage of holometabolous insects that also includes the Raphidoptera. Megaloptera, composed of the families Sialidae and Corydalidae (including subfamilies Chauliodinae and Corydalinae), has fully aquatic larvae that occur in a wide variety of lotic and lentic habitats, including temporary streams. In total, 2 of 17 families of Neuroptera have aquatic larvae: Nevrorthidae live in the benthos of fast-flowing streams and Sisyridae reside on freshwater sponges. A third family of Neuroptera, Osmylidae, contains some water-dependent species that reside under leaves and rocks along the margins of waterbodies. We recognize 328 extant, described species of Megaloptera (composed of 116 species of Chauliodinae, 131 species of Corydalinae, and 81 species of Sialidae) and 73 species of aquatic Neuroptera (composed of 12 species of Nevrorthidae and 61 species of Sisyridae). Additionally, we estimate that 45 species of Osmylidae are water-dependent, although the ecology of this group is poorly understood. Chauliodinae and Corydalidae are both found in the New World, the Oriental region, and South Africa, but are absent from Europe, the Middle East, Central Asia, tropical Africa, and boreal regions. Chauliodinae is quite speciose in Australia, whereas Corydalinae is absent. Sialidae is most speciose in temperate regions, and is absent from tropical Africa and portions of the Oriental region. Sisyridae and Osmylidae are nearly cosmopolitan, but the relict family Nevrorthidae is limited to Japan, the Mediterranean, and Australia. The discovery of many new species in recent years, particularly among Corydalidae in the Neotropics and China, suggests that our knowledge of aquatic neuropterid diversity is far from complete.

Phylogeny and biogeography of the alpine newt Mesotriton alpestris (Salamandridae, Caudata), inferred from mtDNA sequences

In this paper, we performed phylogenetic analyses of Mesotriton alpestris populations from the entire range of species distribution, using fragments of two mtDNA genes, cytochrome b (309 bp) and 16S rRNA (∼500 bp). Sequence diversity patterns and phylogenetic analyses reveal the existence of a relict lineage (Clade A) of late Miocene origin, comprising populations from south-eastern Serbia. This lineage is proposed to be ancestor to a western and an eastern lineage, which diverged during the middle Pliocene. The western lineage is further divided in two clades (Clades B, C) of middle Pliocene origin that represent populations from Italy (B) and populations from central Europe and Iberia (C). Further subdivision, dated back to the middle-late Pliocene, was found within the eastern lineage, representing southern (Clade D) and central-northern (Clade E) Balkan populations, respectively. Extensive sequence divergence, implying greater isolation in multiple refugia, is found within eastern clades, while the western clades seem to have been involved in the colonization of central, western and north-eastern Europe from a hypothetical refugium in central Europe. The extent of divergence does not support the current taxonomy indicating cryptic speciation in the Balkans, while paedomorphic lineages were found to have been evolved during early-middle Pleistocene probably as a response to the ongoing dramatic climatic oscillations.

Discovery of a new basal relict lineage of Madagascan frogs and its implications for mantellid evolution

Discovery of a new basal relict lineage of Madagascan frogs and its implications for mantellid evolution

Discovery of a new basal relict lineage of Madagascan frogs and its implications for mantellid evolution

Frogs of the subfamily Mantellinae (Amphibia: Anura: Mantellidae) are a species-rich and diverse lineage endemic to the Madagascan region. The major synapomorphy of this clade is a derived reproductive mode including an unusual mating behaviour (loss of strong mating amplexus, egg deposition outside of water) and associated morphological adaptations (evolution of femoral glands, loss of nuptial pads). However, the evolutionary steps towards this unique character complex remain obscure. We here describe a recently discovered new frog, Tsingymantis antitra gen. nov., sp. nov. from the moderately dry karstic massif Tsingy de Ankarana in northern Madagascar. The new species is not referable to any existing genus or species groups. A phylogenetic analysis, based on DNA sequences of four mitochondrial genes (12S and 16S rRNA, tRNAVal, cytochrome b) and one nuclear gene (rhodopsin) placed Tsingymantis without significant support as sister taxon of the Mantellinae which was found to be a well-defined monophyletic group (100% Bayesian and 99% bootstrap support). The position of Tsingymantis as the most basal clade of the Mantellinae is in agreement with several morphological and osteological characters, suggesting that this subfamily including Tsingymantis may be a monophyletic group whereas the Boophinae could represent the most basal clade of the Mantellidae. We therefore include Tsingymantis in the Mantellinae in a preliminary way, pending further study. In contrast to the large majority of recent mantellid species which are adapted to humid rainforests, the most basal clades of the three subfamilies show adaptations to relatively dry conditions, indicating that the climate during the early radiation of mantellids (probably in the Eocene) may have been drier than in recent times.

Phylogeny of Chaetanthera (Asteraceae: Mutisieae) reveals both ancient and recent origins of the high elevation lineages

Penalized likelihood analysis of previously published chloroplast DNA (cpDNA) ndhF sequences suggests that the central-southern Andean genus Chaetanthera diverged ca. 16.5 million years (my) ago, well before the uplift of the Andes to their present heights. Penalized likelihood analysis based on new nuclear ribosomal DNA (rDNA) internal transcribed spacer (ITS) sequences indicates that the most relictual lineages occupy high elevation Andean habitats that did not exist until some 10my later. This result is contrary to the expectation that younger habitats should be occupied by phylogenetically younger lineages. The results are interpreted with respect to the development of aridity in lowland habitats during the Miocene and Pliocene, which presumably extinguished the lowland relatives of the high elevation taxa or, in effect, forced them upwards in search of adequate moisture. As the more northerly lineages were being displaced upward, others diversified in the mediterranean-type climate area of central Chile, giving rise to additional high elevation taxa again, at an early date, as well as lowland taxa. Some species of Chaetanthera from lowland central Chile appear as the phylogenetically youngest taxa, suggesting secondary adaptation to lowland aridity. At the same time, at least two high elevation species, Chaetanthera peruviana and Chaetanthera perpusilla, appear to have been derived recently from a lower elevation ancestor, while some middle to low elevation taxa seem to have evolved recently out of a high elevation complex. The results suggest that the younger high elevation habitats have served as both "cradle" and "museum" for Chaetanthera lineages.

Molecular systematics of the Hyaenidae: Relationships of a relictual lineage resolved by a molecular supermatrix

The four extant species of hyenas (Hyaenidae; Carnivora) form a morphologically and ecologically heterogeneous group of feliform carnivorans that are remnants of a formerly diverse group of mammalian predators. They include the aardwolf ( Proteles cristatus), a termite-feeding specialist, and three species with a craniodental morphology adapted to cracking the bones of prey and/or carcasses, the spotted hyena ( Crocuta crocuta), brown hyena ( Parahyaena brunnea), and striped hyena ( Hyaena hyaena). Hyenas have been the subject of a number of systematic studies during the last two centuries, due in large part to the extensive fossil record of the group, with nearly 70 described fossil species. Morphological studies incorporating both fossil and living taxa have yielded different conclusions regarding the evolutionary relationships among living hyenas. We used a molecular supermatrix comprised of seven nuclear gene segments and the complete mitochondrial cytochrome b gene to evaluate phylogenetic relationships among the four extant hyaenid species. We also obtained sequence data from representative species of all the main families of the Feliformia (Felidae, Herpestidae, and Viverridae) to estimate the sister group of the Hyaenidae. Maximum parsimony and maximum likelihood analyses of the supermatrix recovered identical topologies. Furthermore, Bayesian phylogenetic analyses of the supermatrix, with among-site rate variation among data partitions parameterized in three different ways, also yielded the same topology. For each phylogeny reconstruction method, all but two nodes received 100% bootstrap or 1.00 posterior probability nodal support. Within the monophyletic Hyaenidae, Parahyaena and Hyaena were joined together, with Crocuta as the sister to this clade, and Proteles forming the most basal lineage. A clade containing two species of mongoose (core Herpestidae) plus Cryptoprocta ferox (currently classified in Viverridae) was resolved as the sister group of Hyaenidae. The pattern of relationships among the three bone-cracking hyaenids ( Crocuta, Hyaena, and Parahyaena) is incongruent with recent cladistic assessments based on morphology and suggests the need to reevaluate some of the morphological characters that have been traditionally used to evaluate relationships among hyenas. Divergence time estimates based on a Bayesian relaxed molecular clock indicates that hyaenids diverged from their feliform sister group 29.2 MYA, in the Middle Oligocene. Molecular clock estimates also suggest that the origin of the aardwolf is much more recent (10.6 MYA) than that implied by a cladistic analysis of morphology ( ∼ 20 MYA) and suggests that the aardwolf is possibly derived from a bone and meat eating lineage of hyaenids that were present in the Late Miocene. [Hyaenidae; phylogeny; cytochrome b; nuclear gene segments; Proteles; Crocuta; Hyaena; Parahyaena.]

Aquifers: the ultimate groundwater-dependent ecosystems

Australian aquifers support diverse metazoan faunas comprising obligate groundwater inhabitants, largely crustaceans but also including insects, worms, gastropods, mites and fish. They typically comprise short-range endemics, often of relictual lineages and sometimes widely vicariant from their closest relatives. They have been confined to subterranean environments from a range of geological eras and may contain information on the deep history of aquifers. Obligate groundwater fauna (stygobites) occurs in the void spaces in karst, alluvial and fractured rock aquifers. They have convergent morphologies (reduction or loss of eyes, pigment, enhanced non-optic senses, vermiform body form) and depend on energy imported from the surface except in special cases of in situ chemoautotrophic energy fixation. In Australia, many stygofaunas in arid areas occur in brackish to saline waters, although they contain taxa from lineages generally restricted to freshwater systems. They may occur alongside species belonging to taxa considered typical of the marine littoral although far removed in space and time from marine influence. The ecological attributes of stygofauna makes them vulnerable to changes in habitat, which, combined with their taxonomic affinities, makes them a significant issue to biodiversity conservation. The interaction of vegetation and groundwater ecosystems is discussed and, in places, there are conservation issues common to both.

Status, trends and management of sturgeon and paddlefish fisheries

AbstractThe 27 extant species of sturgeons and paddlefishes (Order Acipenseriformes) represent a unique and relict lineage of fishes. Producers of coveted black caviar, sturgeons are one of the most valuable wildlife commodities on earth. The group is among the most endangered fishes with all species listed under Convention on International Trade in Endangered Species (CITES) Appendix I (two species) or II (25 species), only two species considered Lower Risk by IUCN, four of the nine US taxa and one Caspian species protected under the Endangered Species Act, and local extinctions recorded for 19 of 27 species. Despite their well‐publicized imperilled status, commercial pressure on 15 species persists. Here, after reviewing the biological characteristics of sturgeons and paddlefishes and their commercial use, an overview of global fisheries is presented. The synopsis demonstrates that, with few exceptions, sturgeon and paddlefish are imperilled across the globe and long‐term survival in the wild is in jeopardy. All major sturgeon fisheries have surpassed peak productivity levels, with 70% of major fisheries posting recent harvests &lt;15% of historic peak catches and 35% of the fisheries examined crashing within 7–20 years of inception. Even in Caspian Sea fisheries, the most important globally, present catches are below 10% of historic peak landings. Improved domestic and international fisheries management and attention to habitat and species restoration is now needed. Although captive rearing offers promise for caviar alternatives and endangered species restoration, it must advance cautiously to avoid environmental harm. To ensure a continued supply of caviar and the survival of these unique fishes we offer recommendations for priority conservation action for the future.

Comparisons of allozyme variation of narrow endemic and widespread species of Far East Euphorbia (Euphorbiaceae)

Genetic variation from 19 populations representing four species of Euphorbia was compared using isozyme markers. Euphorbia fauriei and E. garanbiensis are rare endemic species in Korea and Taiwan, respectively while E. pekinensis and E. jolkinii are widespread in Korea and Taiwan. A low level of genetic variation and high genetic differentiation among populations was found in E. garanbiensis, which has a restricted distribution, small population sizes, gravity-dispersed seeds, and is possibly a self-pollinator. Alternatively, E. garanbiensis may have recently evolved from a continental progenitor or may be a relictual lineage from the continental flora. The high genetic diversity found in E. fauriei is unusual and may be explained by its recent origin from a widespread continental progenitor, E. pekinensis, An alternative explanation is that E. fauriei survived in refugia during the last glaciation in the Korean peninsula. The idea of progenitor-derivative species pairs between E. pekinensis and E. fauriei is supported by the high genetic identity values between the two species and the putative derivative E. fauriei having no unique allele and lacking some rare alleles present in the putative progenitor E. pekinensis.

Molecular Phylogeny and Biogeography of Tribe Anthemideae (Asteraceae), Based on Chloroplast Gene ndhF

Anthemideae (Asteraceae) is primarily a north temperate, Old World tribe of 109 genera and approximately 1740 species. We sequenced a 1200-bp portion of chloroplast gene ndhF for representative genera and subtribes and constructed a phylogeny for the tribe. There is support for monophyly of subtribes Chrysantheminae and Gonosperminae and for portions of some subtribes. However, our molecular phylogeny differs significantly from traditional classifications and from previously published morphological phylogenies of the tribe. Many South African genera from several different subtribes form a basal grade, indicating multiple, relictual lineages. Eurasian genera form a recently derived clade that includes the Mediterranean genera of the Iberian Peninsula and North Africa. There is little resolution or support for the placement of eastern Asian genera. Apparently, the tribe originated in the Southern Hemisphere, presumably in Africa, with the Eurasian and Mediterranean members being derived from a common ancestor.

Phylogeny of Giant Clams (Cardiidae: Tridacninae) Based on Partial Mitochondrial 16S rDNA Gene Sequences

We have performed the first DNA molecular phylogenetic analysis of giant clams. An approximately 462-nucleotide fragment of the mitochondrial large ribosomal subunit (16S) was sequenced for all eight species of giant clams and two species of an outgroup taxon, the edible cockle Cerastoderma. The data were analyzed using a maximum parsimony approach and a single most parsimonious tree was found. The resulting phylogenetic hypothesis indicates that the genera Hippopus and Tridacna are monophyletic sister taxa. Tridacna (Chametrachea) is the sister taxon to (T. tevoroa (T. derasa+T. gigas)), with these latter three taxa all being placed in a single subgenus, Tridacna (Tridacna). The number of recognized giant clam species has increased by one-third over the last two decades with the discovery of two rare new species having restricted geographic ranges: H. porcellanus (Palau and the Sulu Archipelago) and T. tevoroa (Tonga and Fiji). These two species lack a known fossil record but exhibit greater genetic distances from sister taxa than do extant giant clam species pairs which are recognizable in Neogene strata, e.g., T. gigas/T. derasa and T. maxima/T. squamosa. We propose that the two new species represent ancient relict lineages of Miocene origin.