Phylogeography of the Korean pine (Pinus koraiensis) in northeast Asia: inferences from organelle gene sequences

Range-wide genetic variation of Korean pine (Pinus koraiensis) was assessed using maternally inherited mtDNA and paternally inherited cpDNA for 16 natural populations throughout northeast Asia in order to study its phylogeographical history during the Quaternary. The cpDNA variation indicated that there was no difference between populations on the Asian continent and those in the Japanese archipelago. In contrast, the mtDNA variation indicated that there was significant difference between the populations from the two regions, with each region having a different lineage. The continental populations exhibited no diversity in the mtDNA examined despite the species’ current extensive range and large populations. Conversely, while the Korean pine is rare in Japan, the Japanese populations exhibited greater levels of mtDNA diversity (H _T?=?0.502). The higher mtDNA diversity and evidence from numerous Korean pine macrofossil remains dated to the Pleistocene and recovered various sites in Japan suggest that the Japanese archipelago once served as a refugium to a much larger Korean pine population with a more extensive range than is the case today. The presence of the single mtDNA haplotype across the Asian continent suggests that the present widespread populations could have expanded from a single refugium population after the last glacial periods.     

A contrasted pattern of chromosome evolution in two genera of lemmings,Lemmus and Dicrostonyx (Mammalia,Rodentia)

Lemmings of the genus Lemmus display a very moderate degree of karyotype diversity. In L. lemmus from the Kola Peninsula, L. sibiricus sibiricus from the Pechora inlet coast and the Laptev Sea coast, L.s. portenkoi from the Vrangell Island and L. amurensis from Southern Yakutia the gross chromosome morphology and C-banding pattern proved to be identical (2n = 50, NF = 50). The chromosome set of L.s. chrysogaster (the Chukotka Peninsula) consists of 23 pairs of acrocentrics and 2 pairs of subtelocentrics (2n = 50, NF = 54), and so it is identical to the karyotype of North American Lemmus. As to spatial structure of populations, population dynamics, degree of inbreeding and uniformity of habitats throughout the area, Lemmus is basically similar to the lemmings of another genus, Dicrostonyx. In the latter, however, an extensive chromosome diversity has been found. Therefore, the ecological and population characteristics mentioned above are suggested not to be essential for the rate of chromosome evolution in lemmings.     

Mitochondrial DNA variation and the evolutionary history of chromosome races of collared lemmings (Dicrostonyx) in the Eurasian Arctic

Collared lemmings (Dicrostonyx) demonstrate extensive chromosome variation along their circumpolar distribution in the high Arctic. To reveal the history of this genus and the origin of chromosome races in the Palearctic, we studied the geographical pattern of mtDNA variation in lemmings from 13 localities by using eight tetranucleotide restriction enzymes. The main split in mtDNA phylogeny is at the Bering Strait and corresponds to the main chromosome division between the Beringian and the Eurasian groups of karyotypes. Nucleotide divergence estimate of 6.8% suggests that, despite the Bering Land Bridge, Palearctic and Nearctic forms have been separated since the mid-Pleistocene. Five distinct phylogenetic groups of mtDNA haplotypes, with average divergence of 1.5%, corresponding to geographical regions, were found along the Palearctic coast. Low nucleotide and haplotype diversity and a star-like phylogeny within phylogeographical groups of haplotypes suggest regional bottleneck events in the recent past, most probably due to warming events during the Holocene. There is congruence between phylogeographical pattern of mtDNA variation and geographical distribution of chromosome races; 69% of the total mtDNA variation is allocated among chromosome races. This congruence implies that historical events such as fragmentation and allopatric bottleneck events have been important for the origin of chromosome races. However, historical factors do not explain the fixed autosome fusions found to distinguish certain populations.     

Where to Dig for Fossils: Combining Climate-Envelope,Taphonomy and Discovery Models

Fossils represent invaluable data to reconstruct the past history of life, yet fossil-rich sites are often rare and difficult to find. The traditional fossil-hunting approach focuses on small areas and has not yet taken advantage of modelling techniques commonly used in ecology to account for an organism’s past distributions. We propose a new method to assist finding fossils at continental scales based on modelling the past distribution of species, the geological suitability of fossil preservation and the likelihood of fossil discovery in the field, and apply it to several genera of Australian megafauna that went extinct in the Late Quaternary. Our models predicted higher fossil potentials for independent sites than for randomly selected locations (mean Kolmogorov-Smirnov statistic = 0.66). We demonstrate the utility of accounting for the distribution history of fossil taxa when trying to find the most suitable areas to look for fossils. For some genera, the probability of finding fossils based on simple climate-envelope models was higher than the probability based on models incorporating current conditions associated with fossil preservation and discovery as predictors. However, combining the outputs from climate-envelope, preservation, and discovery models resulted in the most accurate predictions of potential fossil sites at a continental scale. We proposed potential areas to discover new fossils of Diprotodon, Zygomaturus, Protemnodon, Thylacoleo, and Genyornis, and provide guidelines on how to apply our approach to assist fossil hunting in other continents and geological settings.     

Matching loci surveyed to questions asked in phylogeography

Although mitochondrial DNA (mtDNA) has long been used for assessing genetic variation within and between populations, its workhorse role in phylogeography has been criticized owing to its single-locus nature. The only choice for testing mtDNA results is to survey nuclear loci, which brings into contrast the difference in locus effective size and coalescence times. Thus, it remains unclear how erroneous mtDNA-based estimates of species history might be, especially for evolutionary events in the recent past. To test the robustness of mtDNA and nuclear sequences in phylogeography, we provide one of the largest paired comparisons of summary statistics and demographic parameters estimated from mitochondrial, five Z-linked and 10 autosomal genes of 30 avian species co-distributed in the Caucasus and Europe. The results suggest that mtDNA is robust in estimating inter-population divergence but not in intra-population diversity, which is sensitive to population size change. Here, we provide empirical evidence showing that mtDNA was more likely to detect population divergence than any other single locus owing to its smaller N_e and thus faster coalescent time. Therefore, at least in birds, numerous studies that have based their inferences of phylogeographic patterns solely on mtDNA should not be readily dismissed.     

Holarctic phylogeography of the root vole (Microtus oeconomus): implications for late Quaternary biogeography of high latitudes

A species-wide phylogeographical study of the root vole (Microtus oeconomus) was performed using the whole 1140 base pair mitochondrial (mt) cytochrome b gene. We examined 83 specimens from 52 localities resulting in 65 unique haplotypes. Our results demonstrate that the root vole is divided into four main mtDNA phylogenetic lineages that seem to have largely allopatric distributions. Net divergence estimates (2.0-3.5%) between phylogroups, as well as relatively high nucleotide diversity estimates within phylogroups, indicate that the distinct phylogeographical structure was initiated by historical events that predated the latest glaciation. European root voles are divided into a Northern and a Central mtDNA phylogroup. The mtDNA data in concert with fossil records imply that root voles remained north of the classical refugial areas in southern Europe during the last glacial period. The currently fragmented populations in central Europe belong to a single mtDNA phylogroup. The Central Asian and the North European lineages are separated by the Ural Mountains, a phylogeographical split also found in collared lemmings (Dicrostonyx) and the common vole (M. arvalis). The Beringian lineage occurs from eastern Russia through Alaska to northwestern Canada. This distribution is congruent with the traditional boundaries of the Beringian refugium and with phylogeographical work on other organisms. In conclusion, similarities between the phylogeographical patterns in the root vole and other rodents, such as Arctic and subarctic lemmings, as well as more temperate vole species, indicate that late Quaternary geological and climatic events played a strong role in structuring northern biotic communities.     

Landscapes of fear or competition? Predation did not alter habitat choice by Arctic rodents

In systems where predation plays a key role in the dynamics of prey populations, such as in Arctic rodents, it is reasonable to assume that differential patterns of habitat use by prey species represent adaptive responses to spatial variation in predation. However, habitat selection by collared (Dicrostonyx groenlandicus) and brown (Lemmus trimucronatus) lemmings depends on intra- and inter-specific densities, and there has been little agreement on the respective influences of food abundance, predators, and competition for habitat on lemming dynamics. Thus, we investigated whether predation affected selection of sedge-meadow versus upland tundra by collared lemmings in the central Canadian Arctic. We first controlled for the effects of competition on lemming habitat selection. We then searched for an additional signal of predation by comparing habitat selection patterns between 12 control plots and one large grid where lemmings were protected from predators by fencing in 1996 and 1997, but not during 5 subsequent years when we monitored habitat use in the grid as well as in the control plots. Dicrostonyx used upland preferentially over meadows and was more numerous in 1996 and 2011 than in other sample years. Lemmus was also more abundant in 1996 than in subsequent years, but its abundance was too low in the exclosure to assess whether exclusion of predators influenced its habitat selection. Contrary to the effects of competition, predation had a negligible impact on the spatial dynamics of Dicrostonyx, at least during summer. These results suggest that any differences in predation risk between the two habitats have little direct influence on the temporal dynamics of Dicrostonyx even if induced through predator–prey cycles.     

First discovery of Pleistocene orangutan (Pongo sp.) fossils in Peninsular Malaysia: Biogeographic and paleoenvironmental implications

Nine isolated fossil Pongo teeth from two cave sites in Peninsular Malaysia are reported. These are the first fossil Pongo specimens recorded in Peninsular Malaysia and represent significant southward extensions of the ancient Southeast Asian continental range of fossil Pongo during two key periods of the Quaternary. These new records from Peninsular Malaysia show that ancestral Pongo successfully passed the major biogeographical divide between mainland continental Southeast Asia and the Sunda subregion before 500 ka (thousand years ago).     

Taxonomy,phylogeny, and diversity of the extinct Lesser Antillean rice rats (Sigmodontinae: Oryzomyini), with description of a new genus and species

Rice rats (Sigmodontinae: Oryzomyini) are abundant in the Late Quaternary fossil record and in Holocene pre‐Columbian archaeological middens across the Lesser Antilles. All of these rice rats are now extinct, and their regional diversity and systematics remain extremely poorly understood. We redescribe all of the region's rice rat taxa known from adequate diagnostic material (Megalomys desmarestii, Megalomys luciae, and Oligoryzomys victus), and describe a new genus and species, Pennatomys nivalis gen. et sp. nov. , from archaeological sites on St. Eustatius, St. Kitts, and Nevis, which formed a single larger island during Quaternary low sea‐level stands. Cladistic analysis supports the inclusion of O. victus within Oligoryzomys, and identifies Megalomys as a sister group of the large‐bodied genera Sigmodontomys or Sigmodontomys + Nectomys, suggesting that large body size in Megalomys represents phyletic gigantism rather than ‘island gigantism’. Megalomys and Pennatomys belong to an oryzomyine clade that has undergone remarkable radiation throughout the oceanic and continental‐shelf islands of the Neotropical region, but these genera do not represent a monophyletic group within the Nectomys subclade, indicating multiple over‐water colonization events of the Lesser Antillean island chain. Although Lesser Antillean rice rats were heavily exploited by prehistoric Amerindians, it is likely that most or all of these taxa survived until European arrival in the region. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 160 , 748–772.     

Molecular dating and diversification of the South American lizard genus Liolaemus (subgenus Eulaemus) based on nuclear and mitochondrial DNA sequences

The temperate South American lizard genus Liolaemus is the one of the most widely distributed and species‐rich genera of lizards on earth. The genus is divided into two subgenera, Liolaemus sensu stricto (the ‘Chilean group’) and Eulaemus (the ‘Argentino group’), a division that is supported by recent molecular and morphological data. Owing to a lack of reliable fossil data, previous studies have been forced to use either global molecular clocks, a standardized mutation rate adopted from previous studies, or the use of geological events as calibration points. However, simulations indicate that these types of assumptions may result in less accurate estimates of divergence times when clock‐like models or mutation rates are violated. We used a multilocus data set combined with a newly described fossil to provide the first calibrated phylogeny for the crown groups of the clade Eulaemus, and derive new fossil‐calibrated substitution rates (with error) of both nuclear and mtDNA gene regions for Eulaemus specifically. Divergence date estimates for each of the crown groups and appropriate rate estimates will provide the foundation for understanding rates of speciation, historical biogeography, and phylogeographical history for various clades in one of the most diverse lizard genera in the poorly studied Patagonian region. © 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 164 , 825–835.     

Relationships among Cichorium species and related genera as determined by analysis of mitochondrial RFLPs

Mitochondrial DNA polymorphism was employed to assess cytoplasmic diversity among cytoypes of the genus Cichorium and related genera of the tribe Lactuceae (Asteraceae). Hybridization patterns of total DNA using six restriction enzymes and five heterologous mtDNA probes were examined. From estimates of mtDNA diversity, Cichorium spinosum appeared as an ecotype of C. intybus rather than a separate species. Interspecific mtDNA polymorphism in the genus Cichorium was higher than that observed in Cicerbita Crepis, Lactuca and Tragopogon. Molecular data seemed to indicate that Catananche is very distant from the other genera examined. Intergeneric comparisons allowed the clustering of Cicerbita, Lactuca and Cichorium, genera which belong to different subtribes. However, further molecular investigations on a larger number of genera are needed to clarify the relationships among genera within and between subtribes of the tribe Lactuceae.     

Phylogeographic structure and mitochondrial DNA variation in true lemmings (Lemmus) from the Eurasian Arctic

The geographic pattern of mtDNA variation in lemmings from 13 localities throughout the Eurasian Arctic was studied by using eight restriction enzymes and sequencing of the cytochrome b region. These data are used to reveal the vicariant history of Lemmus , and to examine the effect of the last glaciation on mtDNA variation by comparing diversity in formerly glaciated areas to the diversity in non-glaciated areas. Phylogenetic congruence across different Arctic taxa and association between observed discontinuities, and probable Pleistocene barriers, suggest that glacial-interglacial periods were crucial in the vicariant history of Lemmus. Differences in amount of divergence (2.1–9.1%) across different historical barriers indicate chronologically separate vicariant events during the Quaternary. Populations from a formerly glaciated area are no less variable than those in the non-glaciated area. Regardless of glaciation history, no population structure and high haplotype diversity were found within geographic regions. The lack of population structure indicates that populations with high ancestral haplotype diversity shifted their distribution during the Holocene, and that lemmings tracked a changing environment during the Quaternary without reduction of effective population size.     

Examining the Role of Effective Population Size on Mitochondrial and Multilocus Divergence Time Discordance in a Songbird

Estimates of speciation times are subject to a number of potential errors. One source of bias is that effective population size (N_e) has been shown to influence substitution rates. This issue is of particular interest for phylogeographic studies because population sizes can vary dramatically among genetically structured populations across species’ ranges. In this study, we used multilocus data to examine temporal phylogeographic patterns in a widespread North American songbird, the Northern Cardinal (Cardinalis cardinalis). Species tree estimation indicated that the phylogeographic structure of C. cardinalis was comprised of four well-supported mainland lineages with large population sizes (large N_e) and two island lineages comprised of much smaller populations (small N_e). We inferred speciation times from mtDNA and multilocus data and found there was discordance between events that represented island-mainland divergences, whereas both estimates were similar for divergences among mainland lineages. We performed coalescent simulations and found that the difference in speciation times could be attributed to stochasticity for a recently diverged island lineage. However, the magnitude of the change between speciation times estimated from mtDNA and multilocus data of an older island lineage was substantially greater than predicted by coalescent simulations. For this divergence, we found the discordance in time estimates was due to a substantial increase in the mtDNA substitution rate in the small island population. These findings indicate that in phylogeographic studies the relative tempo of evolution between mtDNA and nuclear DNA can become highly discordant in small populations.     

Demography of the upward-shifting temperate woody species of the Rhododendron pseudochrysanthum complex and ecologically relevant adaptive divergence in its trailing edge populations

Trailing edge populations of upward migrating species induced by postglacial climatic warming can be evolutionarily significant in the face of global warming. We tested for population size changes between lower- and higher-elevation populations located in the same mountainous regions of the upward-shifting temperate woody species of the Rhododendron pseudochrysanthum complex in Taiwan. We also tested whether natural selection evoked adaptive divergence in trailing edge populations of this species complex. We genotyped 26 expressed sequence tag-simple sequence repeat (EST-SSR) loci of 185 individuals from nine populations of the R. pseudochrysanthum complex including Rhododendron rubropunctatum, Rhododendron hyperythrum, Rhododendron morii, and R. pseudochrysanthum. R. rubropunctatum populations in the R. pseudochrysanthum complex possessed the lowest estimates of genetic diversity and effective population size. Higher-elevation R. pseudochrysanthum populations had lower effective population sizes than lower-elevation R. morii populations in Hohuanshan and Tahsueshan, as revealed by estimates using both MIGRATE-N and approximate Bayesian computation (ABC). R. rubropunctatum populations diverged significantly from populations of other members of the R. pseudochrysanthum complex. An outlier potentially under positive selection specific to R. rubropunctatum populations was identified and strongly associated with ecologically relevant environmental variables. Postglacial climatic warming has a significant influence on population isolation in the R. pseudochrysanthum complex. The results indicate adaptive evolution in the trailing edge populations, i.e., R. rubropunctatum populations of the upward shifting R. pseudochrysanthum complex.     

The fossil bat assemblages from the Grotta dei Pipistrelli in Pantalica (southeastern Sicily,Italy): Chronological and palaeoecological implications

Bat remains are useful for palaeoecological reconstructions, they provide independent information on palaeoenvironment and are good indicators for hypogean microclimates. Nine taxa of Chiroptera divided into three families (Rhinolophidae, Vespertilionidae and Miniopteridae) and four genera (Rhinolophus, Myotis, Plecotus and Miniopterus) were discovered in three fossil assemblages from the Grotta dei Pipistrelli, in Sicily, a key region for an understanding of Quaternary climates and environments. Bat remains were deposited during three distinct timespans: one late Pleistocene, MIS 2, around the Last Glacial Maximum, and two Holocene, both referable to the Atlantic chronozone. The presence of yearlings, adult and old individuals suggests hibernating colonies, but the cave was also utilized as a nursery. The diversity of taxa indicates a composite landscape with prevailing vegetation cover and relatively warm climatic conditions. The percentage variations of the frequencies of the recognized taxa suggest a progressive increase of open spaces in the middle Holocene.     

Mitogenomic analysis of the Australian lungfish (<Emphasis Type="Italic">Neoceratodus forsteri</Emphasis>) reveals structuring of indigenous riverine populations and late Pleistocene movement between drainage basins

Neoceratodus forsteri: is a freshwater species of Dipnoan currently listed as ‘vulnerable to extinction’ under Australian legislation. The species is restricted to at least two indigenous riverine populations in southeastern Queensland, and several other putatively translocated populations. Current understanding of genetic relationships among populations is based on studies of allozymes, microsatellites and mitochondrial DNA (mtDNA) fragments. A notable feature of all these datasets was low genetic variability. Here we sequence the complete mitogenome of 71 N. forsteri individuals from five populations to improve resolution of mtDNA diversity, examine relationships among populations, and evaluate recent demographic history. We recorded 137 variable positions forming 41 haplotypes in the 16,573 bp mitogenome alignment. Strong genetic structure was observed among riverine samples (global Φ_ST?=?0.342) in a pattern consistent with translocation history. Tinana Creek was confirmed as an isolated and genetically unique subpopulation that should be recognized as a distinct management unit. Two previously unreported mtDNA clades (0.46% mean divergence) were found and suggest that genetic exchange among coastal catchments may have been facilitated by riverine connections on the exposed continental shelf during the late Pleistocene. Extended Bayesian skyline analysis showed no evidence for recent historical change in female effective population size, and codon-based selection tests found no evidence for positive selection in coding genes. Overall, our results emphasise the utility of the full mtDNA molecule for capturing population structure in taxa with low genetic diversity. In such cases, informative variation may be scattered across disparate parts of the mitogenome. Surveying relatively short fragments of mtDNA may lead to significant underestimates of population structure when applied to threatened species with low genetic diversity.     

Chloroplast and Mitochondrial DNA Variation in HORDEUM VULGARE and HORDEUM SPONTANEUM

A survey of restriction fragment polymorphism in Hordeum vulgare and Hordeum spontaneum was made using 17 and 16 hexanucleotide restriction endonucleases on chloroplast (cp) and mitochondrial (mt) DNA, respectively. The plant accessions originated from various places throughout the Fertile Cresent and Mediterranean. The types of changes in cpDNA consisted of nucleotide substitutions and insertions and deletions on the order of 100 base pairs. In contrast, mtDNA has most likely undergone larger insertions and deletions of up to 20 kilobase pairs in addition to rearrangements. Grouping of mtDNA fragment data showed that in some cases geographical affinities existed between the two species, whereas in others there were no clear affinities. Nucleotide diversity estimates derived from the restriction fragment data were used in a number of comparisons of variability. Comparisons of overall mtDNA variability (nucleotide diversity = 9.68 x 10^-4) with cpDNA variability (nucleotide diversity = 6.38 x 10^-4 ) indicated that the former are somewhat more variable. Furthermore, there was no indication that the wild H. spontaneum (cpDNA diversity = 5.57 x 10^-4; mtDNA diversity = 6.04 x 10 ^-4) was more variable than the land races of H. vulgare (cpDNA diversity = 5.88 x 10^-4; mtDNA diversity = 9.79 x 10^-4). In fact, on the basis of mtDNA diversity, H. vulgare was the more variable species. Comparison of organelle nucleotide diversity estimates with an estimate of nuclear nucleotide diversity derived from existing isozyme data provided evidence that both organelle genomes are evolving at a slower rate than the nuclear genome.     

A possible explanation for the population size discrepancy in tuna (genus Thunnus) estimated from mitochondrial DNA and microsatellite data

A recent study using both mitochondrial DNA (mtDNA) and microsatellite data reported on a population size discrepancy in the eastern tiger salamander where the effective population size (N_e) estimate of the former exceeded that of the latter. That study suggested, among other hypotheses, that homoplasy of microsatellite alleles is responsible for the discrepancy. In this investigation, we report 10 new cases of a similar discrepancy in five species of tuna. These cases derive from our Bayesian inferences using data from Pacific Bluefin Tuna (Thunnus orientalis) and Yellowfin Tuna (Thunnus albacares), as well as from published estimates of genetic diversity for additional populations of Yellowfin Tuna and three other tuna species. Phylogenetic character analyses of inferred genealogies of Pacific Bluefin and Yellowfin Tuna reveal similar reduced levels of mtDNA and microsatellite homoplasy. Thus, the discrepancy between inferred population sizes from mtDNA and microsatellite data in tuna is most likely not an artifact of the chosen mutation models used in the microsatellite analyses, but may reflect behavioral differences between the sexes such as female-biased philopatry and male-biased dispersal. This explanation now warrants critical testing with more local populations of tuna and with other animal and plant groups that have different life histories.     

Pyrenean ptarmigans decline under climatic and human influences through the Holocene

In Europe, the Quaternary is characterized by climatic fluctuations known to have led to many cycles of contraction and expansion of species geographical ranges. In addition, during the Holocene, historical changes in human occupation such as colonization or abandonment of traditional land uses can also affect habitats. These climatically or anthropically induced geographic range changes are expected to produce considerable effective population size change, measurable in terms of genetic diversity and organization. The rock ptarmigan (Lagopus muta) is a small-bodied grouse occurring throughout Northern hemispheric arctic and alpine tundra. This species is not considered threatened at a continental scale, but the populations in the Pyrenees are of concern because of their small population size, geographical isolation and low genetic diversity. Here, we used 11 microsatellites to investigate genetic variations and differentiations and infer the overall demographic history of Pyrenean rock ptarmigan populations. The low genetic variability found in these populations has been previously thought to be the result of a bottleneck that occurred following the last glacial maximum (i.e., 10 000 years ago) or more recently (i.e., during the last 200 years). Our results clearly indicate a major bottleneck affecting the populations in the last tenth of the Holocene. We discuss how this decline can be explained by a combination of unfavorable and successive events that increased the degree of habitat fragmentation.     

Systematics and palaeoecology of middle Toarcian Asteroidea (Echinodermata) from the “Seuil du Poitou”, Western France

Complete, articulated starfish fossils are rare. However, more frequently encountered dissociated skeletal elements (ossicles) permit reliable taxonomic identification, making them a valuable data source for diversity estimates. Nearly 300 asteroid ossicles, collected from the middle Toarcian marls in western France can be assigned to five species. Four species and two genera are described: Comptoniaster vrinensis nov. sp. (Goniasteridae), Poncetaster crateri nov. gen. nov. sp. (Stauranderasteridae), Galbaster recurrans nov. gen. nov. sp. (Goniasteridae) and Pentasteria? liasica nov. sp. (Astropectinidae). The known diversity of Early Jurassic asteroids is increased from 12 to 16 species. These taxa illustrate the diversification of crown-group asteroids early in the Jurassic, following the Permo-Triassic crisis. They also reflect bias of the fossil record, and imply the existence of numerous ghost lineages in the evolutionary trees of extant groups. Variation in asteroid diversity across the “Seuil du Poitou” was driven by ecological constraints. The relative frequency (abundance of ossicles and diversity) of goniasterids and stauranderasterids increases in shallower environments. The Benthopectinidae, represented by Plesiastropecten hallovensis, occurred primarily from deep-shelf sediments. Similar ecological patterns are observed for more recent fossil and extant relatives, which further supports the idea of conservative evolution in post-Palaeozoic starfishes since the Early Jurassic.