The ontogeny of cinctans (stem‐group Echinodermata) as revealed by a new genus,GraciaCystis, from the middle Cambrian of Spain

Abstract:  A new cinctan echinoderm, Graciacystis ambigua gen. et sp. nov. from Cambrian Series 3 rocks of Spain, is described based on more than 100 articulated specimens that range from 6 to 14.5 mm in thecal length. This material shows that Graciacystis ambigua, while plastic in thecal shape, is highly conservative in its thecal construction, with a fixed number of marginal plates and very limited addition of plates in the stele and ventral membrane through ontogeny. Ventral swellings on marginal elements are absent from the smallest specimens and become gradually more marked during growth. A cladistic analysis shows Graciacystis to be a basal cinctan, more derived than Sotocinctus and the Trochocystitidae and as sister group to a large clade formed by Sucocystidae + Gyrocystidae. The determinate growth pattern seen in Graciacystis seems to be the general pattern for all cinctans.     

Pædomorphic patterns of the Cambrian genus Alueva (Trilobita, Ellipsocephalidae) from the Iberian Chains (NE Spain)

Three hundred protaspid and meraspid specimens of the trilobite species Alueva undulata Sdzuy, 1961 from the uppermost Bilbilian limestones of the Valdemiedes Formation (Iberian Chains, NE Spain) have been released by the action of acid. A pædomorphocline is proposed embracing the different species of Alueva, based on the comparison of the ontogenic patterns of the species Alueva undulata Sdzuy, 1961, and the adult morphologies of Alueva moratrix (Sdzuy, 1958). This analysis suggests that the species Alueva? hastata (Sdzuy, 1958) is not related to the pædomorphocline, and provides an approach for evaluating the phylogenetic relationships between the species A. undulata and A. moratrix, which occur across the Lower-Middle Cambrian transition in the Iberian Chains, directly linked with the Valdemiedes event.     

A new Transantarctic relationship: morphological evidence for a Rheidae–Dromaiidae–Casuariidae clade (Aves,Palaeognathae, Ratitae)

Although ratites have been studied in considerable detail, avian systematists have been unable to reach a consensus regarding their relationships. Morphological studies indicate a basal split separating Apterygidae from all other extant ratites, and a sister‐group relationship between Rheidae and Struthionidae. Molecular studies have provided evidence for the paraphyly of the Struthionidae and Rheidae, with respect to a clade of Australasian extant ratites. The position of the extinct Dinornithidae and Aepyornithidae also remains hotly debated. A novel pattern of diversification of ratites is presented herein. The phylogenetic analysis is based on 17 taxa and 129 morphological characters, including 77 new characters. The resultant tree yields a sister‐group relationship between New Zealand ratites (Apterygidae plus Dinornithidae) and all other ratites. Within this clade, the Aepyornithidae and Struthionidae are successive sister taxa to a new, strongly supported clade comprising the Rheidae, Dromaiidae, and Casuariidae. The link between South American and Australian biotas proposed here is congruent with numerous studies that have evidenced closely related taxa on opposite sides of the Southern Pacific. These repeated patterns of area relationships agree with current knowledge on Gondwana break‐up, which indicates that Australia and South America remained in contact across Antarctica until the earliest Tertiary. © 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 156 , 641–663.     

Biogeography of the Monimiaceae (Laurales): a role for East Gondwana and long‐distance dispersal,but not West Gondwana

Aim The biogeography of the tropical plant family Monimiaceae has long been thought to reflect the break‐up of West and East Gondwana, followed by limited transoceanic dispersal. Location Southern Hemisphere, with fossils in East and West Gondwana. Methods We use phylogenetic analysis of DNA sequences from 67 of the c. 200 species, representing 26 of the 28 genera of Monimiaceae, and a Bayesian relaxed clock model with fossil prior constraints to estimate species relationships and divergence times. Likelihood optimization is used to infer switches between biogeographical regions on the highest likelihood tree. Results Peumus from Chile, Monimia from the Mascarenes and Palmeria from eastern Australia/New Guinea form a clade that is sister to all other Monimiaceae. The next‐deepest split is between the Sri Lankan Hortonia and the remaining genera. The African Monimiaceae, Xymalos monospora, then forms the sister clade to a polytomy of five clades: (I) Mollinedia and allies from South America; (II) Tambourissa and allies from Madagascar and the Mascarenes; (III) Hedycarya, Kibariopsis and Leviera from New Zealand, New Caledonia and Australia; (IV) Wilkiea, Kibara, Kairoa; and (V) Steganthera and allies, all from tropical Australasia. Main conclusions Tree topology, fossils, inferred divergence times and ances‐tral area reconstruction fit with the break‐up of East Gondwana having left a still discernible signature consisting of sister clades in Chile and Australia. There is no support for previous hypotheses that the break‐up of West Gondwana (Africa/South America) explains disjunctions in the Monimiaceae. The South American Mollinedia clade is only 28–16 Myr old, and appears to have arrived via trans‐Pacific dispersal from Australasia. The clade apparently spread in southern South America prior to the Andean orogeny, fitting with its first‐diverging lineage (Hennecartia) having a southern‐temperate range. The crown ages of the other major clades (II–V) range from 20 to 29 Ma, implying over‐water dispersal between Australia, New Caledonia, New Zealand, and across the Indian Ocean to Madagascar and the Mascarenes. The endemic genus Monimia on the Mascarenes provides an interesting example of an island lineage being much older than the islands on which it presently occurs.     

From natural woodlands to cultivated land: diversity of fruit‐feeding butterflies and beetles in the mid‐Zambezi valley,northern Zimbabwe

We tested the effect of cultivation on butterfly (Nymphalidae: Charaxes) and beetle (Coleoptera: Scarabaeidae: Cetoniinae) species richness and abundance along a cultivation intensification gradient. Results showed significant differences in species richness and abundance between natural woodlands and cultivated landscapes with larger differences in areas of high cultivation intensity. The results indicate that natural woodland clearing for cultivation purposes has negative impacts on arthropod diversity, a situation more severe in highly intensified cultivated areas. Our results imply that mosaics of different land‐use units, each in a different phase of clearance‐cultivation‐abandonment‐recovery‐clearance cycle could counter the negative effects of cultivation intensity on arthropod diversity.     

Cryptic diversity in a widespread live‐bearing fish (Poeciliidae: Belonesox)

Belonesox belizanus Kner (Teleostei: Poeciliidae) is a wide‐spread livebearing species that occurs on the Atlantic Slope of Central America from southern Mexico to northern Costa Rica. Previous work has noted morphological variation within the species, and recognized two subspecies: Belonesox belizanus belizanus and Belonesox belizanus maxillosus. We used 1122 bp of cytochrome b and 617 bp of S7‐1 DNA to conduct a phylogeographical study of Belonesox, aiming to examine the genetic distinctiveness of these taxa and other populations of Belonesox throughout the range. Bayesian phylogenetic and haplotype analyses indicated that B. b. maxillosus is not distinctive from other northern populations of Belonesox. However, a distinct phylogeographical break is evident near the Rio Grande in southern Belize. One clade comprises the putative B. b. maxillosus and all populations sampled north of the Rio Grande. The other clade comprises the Rio Grande and all populations south thereof. Fossil‐calibrated divergence time estimates suggest that isolation of the northern and southern lineages of Belonesox occurred approximately 14.1 Mya. The phylogeographical structure recovered in the present study is interesting, considering that relatively few studies have examined molecular variation across this portion of Middle America in a time‐calibrated framework. Furthermore, the present study suggests that more work is needed to adequately understand the factors that have shaped diversity of this region. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 109 , 848–860.     

Testing,as opposed to supporting,the Mid‐domain Hypothesis: a response to Lees and Colwell (2007)

Both our analysis ( Kerr et al. 2006 ), and Lees and Colwell's (2007) reanalysis, of patterns of bird and mammal diversity on Madagascar show that the central peak of richness predicted by the Mid‐Domain Hypothesis (MDH) is not observed. Lees and Colwell emphasize an observation consistent with MDH predictions: a latitudinal mid‐domain richness peak in the rainforest biome. They find (but do not mention) that no analogous peak is observed in the other two main Madagascan biomes. MDH fails nearly all its tests in Madagascar.     

Habitat‐driven diversification,hybridization and cryptic diversity in the Fork‐tailed Drongo (Passeriformes: Dicruridae: Dicrurus adsimilis)

Species complexes of widespread African vertebrates that include taxa distributed across different habitats are poorly understood in terms of their phylogenetic relationships, levels of genetic differentiation and diversification dynamics. The Fork‐tailed Drongo (Dicrurus adsimilis) species complex includes seven Afrotropical taxa with parapatric distributions, each inhabiting a particular bioregion. Various taxonomic hypotheses concerning the species limits of the Fork‐tailed Drongo have been suggested, based largely on mantle and upperpart coloration, but our understanding of diversity and diversification patterns remains incomplete. Especially given our lack of knowledge about how well these characters reflect taxonomy in a morphologically conservative group. Using a thorough sampling across Afrotropical bioregions, we suggest that the number of recognized species within the D. adsimilis superspecies complex has likely been underestimated and that mantle and upperpart coloration reflects local adaptation to different habitat structure, rather than phylogenetic relationships. Our results are consistent with recent phylogeographic studies of sub‐Saharan African vertebrates, indicating that widespread and often morphologically uniform species comprise several paraphyletic lineages, often with one or more of the lineages being closely related to phenotypically distinct forms inhabiting a different, yet geographically close, biome.     

Revealing the diversity of a once small taxon: the genus Selenoribates (Acari,Oribatida, Selenoribatidae)

Three new intertidal oribatid species, Selenoribates elegans sp. n., Selenoribates quasimodo sp. n. and Selenoribates satanicus sp. n. are described from the archipelago of Bermuda. Selenoribates elegans sp. n. is characterized by its slender body shape, Selenoribates quasimodo sp. n. possesses a hunchback in lateral view and Selenoribates satanicus sp. n. exhibits two horn-like projections on its anterior gastronotic region. Based on these new findings, the number of Selenoribates species doubled at once and the distribution of this genus, formerly limited to the Mediterranean and the Red Sea, includes now occurrences in the Atlantic and Indo-pacific Ocean as well. The morphology of Selenoribates quasimodo sp. n. and Selenoribates satanicus sp. n. deviates conspicuously from the other known members of Selenoribates, thus indicating that not only the number of species but also the anatomy of this genus is more diverse than formerly supposed. Nymphs of Selenoribates quasimodo sp. n. show an interesting case of ontogenetic neotrichy, with gastronotic setae being duplicated with each moult.     

Ancient vicariance and climate‐driven extinction explain continental‐wide disjunctions in Africa: the case of the Rand Flora genus Canarina (Campanulaceae)

Transoceanic distributions have attracted the interest of scientists for centuries. Less attention has been paid to the evolutionary origins of ‘continent‐wide’ disjunctions, in which related taxa are distributed across isolated regions within the same continent. A prime example is the ‘Rand Flora’ pattern, which shows sister taxa disjunctly distributed in the continental margins of Africa. Here, we explore the evolutionary origins of this pattern using the genus Canarina, with three species: C. canariensis, associated with the Canarian laurisilva, and C. eminii and C. abyssinica, endemic to the Afromontane region in East Africa, as case study. We infer phylogenetic relationships, divergence times and the history of migration events within Canarina using Bayesian inference on a large sample of chloroplast and nuclear sequences. Ecological niche modelling was employed to infer the climatic niche of Canarina through time. Dating was performed with a novel nested approach to solve the problem of using deep time calibration points within a molecular dataset comprising both above‐species and population‐level sampling. Results show C. abyssinica as sister to a clade formed by disjunct C. eminii and C. canariensis. Miocene divergences were inferred among species, whereas infraspecific divergences fell within the Pleistocene–Holocene periods. Although C. eminii and C. canariensis showed a strong genetic geographic structure, among‐population divergences were older in the former than in the latter. Our results suggest that Canarina originated in East Africa and later migrated across North Africa, with vicariance and aridification‐driven extinction explaining the 7000 km/7 million year divergence between the Canarian and East African endemics.     

Temperature change as a driver of spatial patterns and long‐term trends in chironomid (Insecta: Diptera) diversity

Anthropogenic activities have led to a global decline in biodiversity, and monitoring studies indicate that both insect communities and wetland ecosystems are particularly affected. However, there is a need for long‐term data (over centennial or millennial timescales) to better understand natural community dynamics and the processes that govern the observed trends. Chironomids (Insecta: Diptera: Chironomidae) are often the most abundant insects in lake ecosystems, sensitive to environmental change, and, because their larval exoskeleton head capsules preserve well in lake sediments, they provide a unique record of insect community dynamics through time. Here, we provide the results of a metadata analysis of chironomid diversity across a range of spatial and temporal scales. First, we analyse spatial trends in chironomid diversity using Northern Hemispheric data sets overall consisting of 837 lakes. Our results indicate that in most of our data sets, summer temperature (T_jul) is strongly associated with spatial trends in modern‐day chironomid diversity. We observe a strong increase in chironomid alpha diversity with increasing T_jul in regions with present‐day T_jul between 2.5 and 14°C. In some areas with T_jul > 14°C, chironomid diversity stabilizes or declines. Second, we demonstrate that the direction and amplitude of change in alpha diversity in a compilation of subfossil chironomid records spanning the last glacial–interglacial transition (~15,000–11,000 years ago) are similar to those observed in our modern data. A compilation of Holocene records shows that during phases when the amplitude of temperature change was small, site‐specific factors had a greater influence on the chironomid fauna obscuring the chironomid diversity–temperature relationship. Our results imply expected overall chironomid diversity increases in colder regions such as the Arctic under sustained global warming, but with complex and not necessarily predictable responses for individual sites.     

Southern montane populations did not contribute to the recolonization of West Siberian Plain by Siberian larch (Larix sibirica): a range‐wide analysis of cytoplasmic markers

While many species were confined to southern latitudes during the last glaciations, there has lately been mounting evidence that some of the most cold‐tolerant species were actually able to survive close to the ice sheets. The contribution of these higher latitude outposts to the main recolonization thrust remains, however, untested. In the present study, we use the first range‐wide survey of genetic diversity at cytoplasmic markers in Siberian larch (Larix sibirica; four mitochondrial (mt) DNA loci and five chloroplast (cp) DNA SSR loci) to (i) assess the relative contributions of southern and central areas to the current L. sibirica distribution range; and (ii) date the last major population expansion in both L. sibirica and adjacent Larix species. The geographic distribution of cpDNA variation was uninformative, but that of mitotypes clearly indicates that the southernmost populations, located in Mongolia and the Tien‐Shan and Sayan Mountain ranges, had a very limited contribution to the current populations of the central and northern parts of the range. It also suggests that the contribution of the high latitude cryptic refugia was geographically limited and that most of the current West Siberian Plain larch populations likely originated in the foothills of the Sayan Mountains. Interestingly, the main population expansion detected through Approximate Bayesian Computation (ABC) in all four larch species investigated here pre‐dates the LGM, with a mode in a range of 220 000–1 340 000 years BP. Hence, L. sibirica, like other major conifer species of the boreal forest, was strongly affected by climatic events pre‐dating the Last Glacial Maximum.     

Molecular systematics,biogeography and taxonomy of forest‐falcons in the Micrastur ruficollis species complex (Aves: Falconidae)

We gathered molecular data to assess phylogenetic and phylogeographic patterns for widespread lineages of Neotropical forest falcons in the genus Micrastur to: 1) investigate the comparative phylogeography of four species from the M. ruficollis complex (M. ruficollis, M. gilvicollis, M. plumbeus and M. mintoni), to identify the temporal and spatial context of the group's diversification; and 2) to reevaluate, based on molecular characters, the taxonomic status and interspecific boundaries within this complex. Molecular phylogenies were based on sequences of the mitochondrial genes ND2 and Cyt b and the nuclear genes FIB5 and MUSK from 119 specimens, including M. mirandollei and M. semitorquatus as outgroups. The phylogenetic trees obtained by BI and a Species Tree analysis recovered the monophyly of currently accepted species belonging to the M. ruficollis complex. The dates in our tree indicate that the separation of species within the complex occurred 2–4 million yr ago, initiating during the Neogene (Pliocene). However, when compared to most such widely distributed Neotropical lineages, the diversification within the M. ruficollis complex appears more recent (i.e. centered in the Late Pleistocene). Our results demonstrate the existence of eleven geographic lineages (subclades) in M. ruficollis, M. gilvicollis and M. mintoni, which differ genetically from each other and therefore can be interpreted as distinct evolutionary lineages and possibly separate species under lineage‐based species concepts. However, BPP results failed to recognize with strong statistical support any of these subclades as distinct species. Distinct subclades in the M. ruficollis complex are limited by the principal tributaries of the Amazon River and the Andes, suggesting that these modern barriers limit gene flow and thereby could have promoted differentiation mostly during the Pleistocene. However, our results indicate widely disparate responses to individual barriers across subclades, supporting lineage‐specific histories throughout the Neotropics.     

Long‐term ecological data for conservation: Range change in the black‐billed capercaillie (Tetrao urogalloides) in northeast China (1970s–2070s)

Long‐term ecological data can be an effective tool to help ecologists integrate future projections with historical contexts and provide unique insights into the long‐term dynamics of endangered species. However, hampered by data limitations, including incomplete and spatially biased data, relatively few studies have used multidecadal datasets or have examined changes in biogeography from a historical perspective. The black‐billed capercaillie (Tetrao urogalloides) is a large capercaillie (classified as Least Concern [LC] on the IUCN red list) that has undergone a dramatic decline in population during the late 20th century and is considered endangered. Its conservation status is pessimistic, and the species requires immediate protection. Therefore, we supplemented a historical dataset to identify changes in this bird's range and population in northeast China over the long term. The study area spanned Heilongjiang Province, Jilin Province, and the northeast corner of Inner Mongolia in northeast China. We integrated an ecological niche model (BIOMOD2) with long‐term ecological data on this species to estimate the magnitude of change in distribution over time. Our results revealed a 35.25% reduction in the current distribution of this species compared to their potential distribution in the 1970s. This decline is expected to continue under climate change. For example, the future range loss was estimated to be 38.79 ± 0.22% (8.64–90.19%), and the actual state could be worse, because the baseline range of the model was greater than the real range in the 2000s, showing a 12.39% overestimation. To overcome this poor outlook, a conservation strategy should be established in sensitive areas, including the southwestern Greater Khingan Mountains and northern Lesser Khingan Mountains. Actions that should be considered include field investigations, establishing a monitor network, designing ecological corridors, and cooperating with local inhabitants, governments, and conservation biologists to improve the conservation of the black‐billed capercaillie.     

Body‐color and behavioral responses by the mid‐instar nymphs of the desert locust,Schistocerca gregaria (Orthoptera: Acrididae) to crowding and visual stimuli

The effects of crowding and isolation on body color and behavior were observed for the mid‐instar nymphs of the desert locust, Schistocerca gregaria. Some of the solitarious (isolation‐reared) nymphs that were crowded for 1 or 4 h during the third instar developed black patterns at the fourth instar, but most individuals remained unaffected. Black patterns appeared in all individuals that were crowded for 1 day or longer, but even after 4 days of crowding the black patterning for some individuals was not as intense as that for the gregarious (crowd‐reared) controls. Isolation of gregarious nymphs caused the black patterns to recede or disappear at the last (fifth) nymphal instar, but it was necessary to isolate the nymphs from the beginning of the first instar to obtain body coloration looking like solitarious nymphs in most individuals. Solitarious nymphs that were allowed to see gregarious nymphs developed different intensities of black patterns depending on the body size and number of nymphs shown. The behavioral phase shift from one phase to another was observed when the nymphs were crowded or isolated for 2 days or longer, as previously reported for the last nymphal instars of the same strain. Behavioral gregarization was induced for isolated nymphs that were allowed to see a group of nymphs through a transparent double wall. These results suggested that body‐color phase shift occurred more rapidly for mid‐instar nymphs than for late instar nymphs but the rate of behavioral phase shift was similar for the two instars.