Molecular evidence for the pattern and timing of cladogenesis in dasyurid marsupials

Recent molecular studies have provided estimates of phylogeny for nearly all living and recently extinct species in the Order Dasyuromorphia, the dominant clade of insectivorous‐carnivorous marsupials in Australasia. We review these studies along with morphology‐based ones, and present an analysis of all cytochrome b, 12S rRNA, and protamine Pl gene sequences available. In light of these results, we provide a revised suprageneric classification and assess the implications of molecular and paleontological data for dasyurid cladogenesis. Molecular results divide extant dasyurids (Dasyuridae) into four major clades apart from the numbat (Myrmecobiidae) and thylacines (Thylacinidae). We recognize these clades as tribes Dasyurini (Dasyurus, Phascolosorex, and allied genera) and Phascogalini (Antechinus, Murexia, Phascogale) in the Subfamily Dasyurinae, and tribes Sminthopsini (Sminthopsis, Ningaui, Antechinomys) and Planigalini (Planigale) in the Subfamily Sminthopsinae. Each tribe shows a basal radiation of lineages corresponding to genera or species groups. Our results concur with the most recent previous synthesis of dasyurid phylogeny in many respects, but subsumption of New Guinean ‘phascolosoricines’ and ‘muricines’ within Dasyurini and Phascogalini, respectively, constitute significant differences. In particular, the sister‐pairing of ‘phascolosoricines’ with a Dasyurus‐Sarcophilus clade implied by molecular data is difficult to reconcile with anatomy. Divergence rates of mitochondrial sequences are calibrated approximately by comparing thylacine‐to‐dasyurid distances with the age of the oldest thylacinid (Badjcinus, latest Oligocene). Estimated cladogenic dates suggest that extant subfamilies shared a common ancestor around 24 Mya and that major radiations began late in the mid‐Miocene, consistent with the results of previous paleontological studies. The late‐middle and late Miocene corresponds to an episode of faunal turnover in Australian marsupials (including the decline of thylacinid and bandicoot genera, as well as the rise of dasyurids) and to a time when uplift of the New Guinean highlands accelerated the transition from rainforest to drier habitats. Our findings are consistent with the hypothesis that continent‐wide climate changes modulated macroevolution across these independent marsupial clades.     

High diversity Pleistocene rainforest Dasyurid assemblages with implications for the radiation of the dasyuridae

It is commonly accepted that dasyurids (Marsupialia: Dasyuridae) radiated in the late Miocene or early Pliocene in response to a drying trend in Australia's climate as evidenced from the high diversity of dasyurids from modern arid environments compared with Miocene rainforest assemblages. However, mid‐Pleistocene dasyurid assemblages from cave deposits at Mt Etna, Queensland are more diverse than any previously known from rainforest habitats. New taxa will be described elsewhere, but include three new genera as well as new species of Dasyurus, Antechinus and Phascogale. Comparison of dasyurids from Mt Etna sites that are interpreted as rainforest palaeoenvironments with fossil and extant assemblages indicate that they are at least as diverse as those from modern arid environments. Thus Neogene diversification of dasyurids occurred in both arid and rainforest habitats, but only the former survived continuing aridification. Hence, aridification cannot be invoked for the diversification of all dasyurid lineages.     

A Reexamination of Proposed Morphology-Based Synapomorphies for the Families of Dasyuromorphia (Marsupialia). I. Dasyuridae

The validity of eight morphological features previously advanced as synapomorphic for Dasyuridae is investigated in the light of new fossil and molecular data. Results indicate that one of these features (alisphenoid–periotic enclosure of the foramen ovale) is common to outgroups for Dasyuromorphia. Another feature (loss of intestinal cecum) is a likely synapomorphy for Dasyuromorphia. Two features (development of a hypoconulid notch, enlargement of stylar cusp D) may represent shared–derived characters within Dasyuromorphia but not at the family level for Dasyuridae (i.e., probably unite Dasyuridae–Thylacinidae). Another two features (loss of posterolateral palatine foramina, reduction of P₃) are also apomorphic within Dasyuromorphia but unite specialized clades within Dasyuridae. Only two previously treated features are probable synapomorphies for the family (enlargement of the alisphenoid tympanic wing and development of a distinct periotic hypotympanic sinus). An additional feature is identified as a dasyurid synapomorphy (presence of a distinct tubal foramen). Of all putative synapomorphies proposed to date, only the presence of a periotic hypotympanic sinus and tubal foramen are unique for Dasyuridae among dasyuromorphians. Results suggest considerable homoplasy for basicranial features within Dasyuromorphia. Independent acquisition for alisphenoid enclosure of the foramen ovale, development of secondary foramina ovale and loss of posterolateral palatal foramina has occurred in derived thylacinid and dasyurid clades. Convergence is also indicated for hypertrophy of the alisphenoid tympanic wing shown for dasyurids and myrmecobiids, and the development of a squamosal epitympanic sinus in Thylacinidae, Dasyuridae, and Myrmecobiidae. The finding of plesiomorphy for alisphenoid–periotic enclosure of the foramen ovale within Dasyuromorphia undermines the strongest morphology-based synapomorphy uniting a monophyletic Dasyuridae–Myrmecobiidae. Phylogenetic placement for some plesiomorphic fossil dasyuromorphians, known only from dental material, within Dasyuridae is currently untenable, with no dental synapomorphies uniting the family. The value of identifying morphoclines within clades known from robust phylogenetic data for consideration in character analysis is stressed, as is the importance of form–function and ontogenetic data.     

Caribbean reef coral diversity during the early to middle Miocene: an example from the Anguilla Formation

Reefal units in the early to middle Miocene of Anguilla consist of small, irregular lenses of variable coral composition which developed on a shallow, isolated offshore carbonate platform. They are composed of three distinct coral biofacies (branched, mound-shaped, and platy), which are haphazardly distributed in association with inter-reef sands. These units most probably formed as patch reefs across a broad, shallow area that was exposed to moderate energy conditions and periodically affected by storms. No evidence supports the existence of a more extensive barrier reef system. Comparisons with Oligocene and Mio-Pliocene reefs suggest that during the early to middle Miocene, Caribbean reefs were generally smaller in size (<100 m³) and lower in diversity (21 species in Anguilla, 42 species in total across the Caribbean) than Caribbean reefs during the late Oligocene or during the ate Miocene to early Pliocene (71 species in the Dominican Republic, 80 species total across the Caribbean). The early to middle Miocene Caribbean reef coral fauna was dominated by nine widespread species that occur in deposits of similar age in both Anguilla and Panama. More than half of the fauna consisted of Oligocene relicts. Of the 21 genera that first appeared in the Caribbean during Miocene time, 14 had first occurrences after the middle Miocene, as barrier reef systems became more prevalent across the central Caribbean.     

Radiolarian faunal turnover across the Oligocene/Miocene boundary in the equatorial Pacific Ocean

The global warming trend of the latest Oligocene was interrupted by several cooling events associated with Antarctic glaciations. These cooling events affected surface water productivity and plankton assemblages. Well-preserved radiolarians were obtained from upper Oligocene to lower Miocene sediments at Ocean Drilling Program (ODP) Leg 199 Sites 1218 and 1219 in the equatorial Pacific, and 110 radiolarian species were identified.Four episodes of significant radiolarian faunal changes were identified: middle late Oligocene (27.5 to 27.3 Ma), latest Oligocene (24.4 Ma), earliest Miocene (23.3 Ma), and middle early Miocene (21.6 Ma). These four episodes approximately coincide with increases and decreases of biogenic silica accumulation rates and increases in δ¹⁸O values coded as “Oi” and “Mi” events. These data indicate that Antarctic glaciations were associated with change of siliceous sedimentation patterns and faunal changes in the equatorial Pacific.Radiolarian fauna was divided into three assemblages based on variations in radiolarian productivity, species richness and the composition of dominant species: a late Oligocene assemblage (27.6 to 24.4 Ma), a transitional assemblage (24.4 to 23.3 Ma) and an early Miocene assemblage (23.3 to 21.2 Ma). The late Oligocene assemblage is characterized by relatively high productivity, low species richness and four dominant species of Tholospyris anthophora, Stichocorys subligata, Lophocyrtis nomas and Lithelius spp. The transitional assemblage represents relatively low values of productivity and species richness, and consists of three dominant species of T. anthophora, S. subligata and L. nomas. The characteristics of the early Miocene assemblage are relatively low productivity, but high species richness. The two dominant species present in this assemblage are T. anthophora and Cyrtocapsella tetrapera. The most significant faunal turnover of radiolarians is marked at the boundary between the transitional/early Miocene assemblages.We also reviewed changes in other microfossil assemblages in the low latitudes during the late Oligocene through early Miocene. The microfossil assemblages of major groups show sequential changes near the Oligocene/Miocene (O/M) boundary (23.8 Ma). Many extinction events and some first occurrences of calcareous nannofossils and many occurrences of radiolarians are found from about 24.8 to 23.3 Ma, and first occurrences of planktic foraminifers and diatoms followed from 23.2 through 22 Ma. Hence, the O/M boundary is identified as a significant level for microfossil evolutions.     

DNA Sequence Analysis of Familial Relationships Among Dasyuromorphian Marsupials

Although modern morphological and molecular analyses support the monophyly of the Australasian marsupial order Dasyuromorphia, there is much less certainty about relationships among its constituent families (Dasyuridae, Myrmecobiidae, and Thylacinidae). While most authors regard Dasyuridae as monophyletic, a few have suggested that thylacines, numbats, or both have their closest relatives among dasyurids. Recent morphocladistic studies have identified several basicranial characters as putative synapomorphies of dasyurids, but no features that clearly implicate thylacinids, myrmecobiids, or both, as the sister group of Dasyuridae. Only two previous DNA studies have included both thylacine and numbat sequences along with dasyurids, and neither provided strong resolution of interfamilial relationships. In this study, we report a more thorough analytical treatment of complete cytochrome b, 12S rRNA, and protamine P1 gene sequences from dasyuromorphians than has heretofore been attempted. Our results concur with previous morphological studies in showing that Dasyuridae is monophyletic and with immunological findings that thylacinids and dasyurids are sister groups, apart from myrmecobiids. However, the level of support for nodes is highly dependent on the method of phylogenetic analysis employed. Our results also suggest that partitioning of sequence data sets to account for substitutional heterogeneity within and among genes does not necessarily lead to a major reduction in the precision of estimated phylogenies.     

The phylogenetic placement and biogeographical origins of the New Zealand stick insects (Phasmatodea)

The Lanceocercata are a clade of stick insects (Phasmatodea) that have undergone an impressive evolutionary radiation in Australia, New Caledonia, the Mascarene Islands and areas of the Pacific. Previous research showed that this clade also contained at least two of the nine New Zealand stick insect genera. We have constructed a phylogeny of the Lanceocercata using 2277 bp of mitochondrial and nuclear DNA sequence data to determine whether all nine New Zealand genera are indeed Lanceocercata and whether the New Zealand fauna is monophyletic. DNA sequence data were obtained from mitochondrial cytochrome oxidase subunits I and II and the nuclear large subunit ribosomal RNA and histone subunit 3. These data were subjected to Bayesian phylogenetic inference under a partitioned model and maximum parsimony. The resulting trees show that all the New Zealand genera are nested within a large New Caledonian radiation. The New Zealand genera do not form a monophyletic group, with the genus Spinotectarchus Salmon forming an independent lineage from the remaining eight genera. We analysed Lanceocercata apomorphies to confirm the molecular placement of the New Zealand genera and to identify characters that confirm the polyphyly of the fauna. Molecular dating analyses under a relaxed clock coupled with a Bayesian extension to dispersal‐vicariance analysis was used to reconstruct the biogeographical history for the Lanceocercata. These analyses show that Lanceocercata and their sister group, the Stephanacridini, probably diverged from their South American relatives, the Cladomorphinae, as a result of the separation of Australia, Antarctica and South America. The radiation of the New Caledonian and New Zealand clade began 41.06 million years ago (mya, 29.05–55.40 mya), which corresponds to a period of uplift in New Caledonia. The main New Zealand lineage and Spinotectarchus split from their New Caledonian sister groups 33.72 (23.9–45.62 mya) and 29.9 mya (19.79–41.16 mya) and began to radiate during the late Oligocene and early Miocene, probably in response to a reduction in land area and subsequent uplift in the late Oligocene and early Miocene. We discuss briefly shared host plant patterns between New Zealand and New Caledonia. Because Acrophylla sensu Brock & Hasenpusch is polyphyletic, we have removed Vetilia Stål from synonymy with Acrophylla Gray.     

The evolution of protamine P1 genes in dasyurid marsupials

We report the complete DNA sequences of the protamine P1 gene and flanking regions for 13 species of the marsupial family Dasyuridae. The structure of the protamine locus is conserved in dasyurids and consists of two exons (of lengths 142–151 and 47 bp) separated by an intron (208–240 bp). A key feature of the dasyund intron is a 38–40 by duplication found in all species examined to date. This duplication apparently predates the radiation of modern dasyurid lineages and may be homologous to a similar feature in the marsupial mole (Notoryctes). Sequences from a species of Planigale demonstrate that this genus is unique among marsupials in possessing cysteine residues in its protamine P1 molecules. Cysteines may provide enhanced chemical stability for condensed sperm nuclei, a physiological feature that would converge on the common eutherian pattern. Phylogenetic analysis of the protamine genes yields a tree that is largely congruent with previous molecular systematic studies in two areas: (1) There are three main dasyurid lineages corresponding to the Sminthopsinae, Dasyurinae, and Phascogalinae; (2) Dasyurinae and Phascogalinae are sister groups. This study is the first estimate of dasyurid relationships based on a nuclear DNA sequence. Correspondence to: J.D. Retief     

DNA phylogeny of the marsupial wolf resolved.

The phylogenetic position of the recently extinct marsupial ''wolf'', or thylacine (Thylacinus cynocephalus), has been a source of contention in mammalian systematics for nearly a century. Thylacines were endemic to Australasia, but possessed striking anatomical similarities to Oligo-Miocene borhyaenid marsupials of South America. At issue has been whether these features are indicative of common ancestry or convergent adaptation to carnivory. Recent morphological studies have supported both conclusions. Although current marsupial classifications group thylacines with Australian dasyuromorphians, this putative clade is characterized by mostly primitive morphological features. Attempts to determine thylacine affinities with ancient protein and DNA analyses have supported, but not resolved, a dasyuromorphian placement. We report 1546 bp of mitochondrial DNA sequence (from cytochrome b and 12S rRNA genes) and 841 bp of nuclear protamine gene sequence from the thylacine and representatives of all or most other marsupial orders. Phylogenetic analysis of these sequences shows unambiguously that thylacines are members of Dasyuromorphia, and suggests a late Oligocene or very early Miocene divergence of familial lineages.     

Molecular Relationships of the Extinct Pig-Footed Bandicoot Chaeropus ecaudatus (Marsupialia: Perameloidea) Using 12S rRNA Sequences

The pig-footed bandicoot, Chaeropus ecaudatus, is presumed to be extinct as no specimens have been collected or seen since early this century. Usually classified as a specialized member of the family Peramelidae, there is nevertheless still some doubt as to its taxonomic affinities, because this animal is highly specialized and shows several uniquely derived characters. We report here the first attempt to determine the molecular relationships of this animal using mitochondrial 12S rRNA sequences derived from spirit-preserved museum specimens. Phylogenetic analysis shows that the sequence derived from the Chaeropus sample is clearly that of a bandicoot. Within the bandicoot clade, the pig-footed bandicoot is quite distinct from all other taxa. Divergence-time estimates from the 12S rRNA sequences suggest that Chaeropus diverged from the other bandicoot genera in the late Oligocene or early Miocene and that bandicoots diverged from other Australian families in the late Paleocene–early Eocene.     

Tortoise (Reptilia,Testudinidae) radiations in Southern Africa from the Eocene to the present

Africa, inclusive of the West Indian Ocean islands, harbours 11 of the world's 16 extant testudinid genera. Fossil records indicate that testudinids originated in Asia and dispersed first to North America and Europe (Early Eocene) and later to Africa (Late Eocene). We used mitochondrial (1870 bp) and nuclear (1416 bp) DNA sequence data to assess whether molecular data support the late cladogenesis of Southern African testudinid lineages. Our results revealed strong support for the monophyly of a clade consisting of Kinixys, the two Malagasy genera and four Southern African genera (Psammobates, Stigmochelys, Homopus and Chersina). Kinixys diverged from this clade in the Late Palaeocene, suggesting that testudinids occupied Africa at an earlier date than indicated by fossil records. The Southern African tortoises consist of three, strongly supported clades: Psammobates + Stigmochelys; the five‐toed Homopus + Chersina; and the four‐toed Homopus. Due to the paraphyly of Homopus, we propose the taxonomic resurrection of Chersobius for the five‐toed Homopus species (boulengeri, signatus and solus). Cladogenesis at the genus level occurred mainly in the Eocene, with Chersina and Chersobius diverging in the Oligocene. The latter divergence coincided with species‐level radiations within Homopus (areolatus and femoralis) and Psammobates (oculifer, geometricus and tentorius). Our phylogeny could not resolve relationships within Psammobates, indicating rapid speciation between the Late Oligocene and Early Miocene. The Chersobius species were the last to diverge in the Early to Mid‐Miocene. By the Mid‐Miocene, P. tentorius started to differentiate into four lineages instead of the three recognized subspecies: P. t. tentorius, P. t. trimeni and two P. t. verroxii subclades occurring north and south of the Orange River, respectively. Terminal radiations in several taxa suggest the existence of cryptic species and a more diverse tortoise fauna than currently recognized. Factors contributing to this diversity may include the early origin of African testudinids and climatic fluctuations over a heterogeneous landscape.     

Contrasting evolutionary history of hedgehogs and gymnures (Mammalia: Erinaceomorpha) as inferred from a multigene study

The subfamilies Erinaceinae and Galericinae of the extant family Erinaceidae are the only living representatives of the once diverse taxon Erinaceomorpha. In the present study, we performed the first multilocus analysis of phylogenetic relationships among genera of Erinaceidae and estimated the split times between and within the two subfamilies. The analyses of five nuclear and two mitochondrial genes produced a well‐resolved molecular phylogeny. Generally, the molecular tree is compatible with the morphology‐based taxonomy proposed by Frost, Wozencraft & Hoffmann with the exception of the position of Mesechinus, which is placed as the closest sister taxon of Hemiechinus. Another point of contradiction between molecular and morphological phylogenies is the position of Hylomys megalotis, which was consistently placed as the most basal branch among all gymnures in molecular analyses. Genetic relationships between Erinaceus and Atelerix remain unclear, suggesting a hard trichotomy among these two lineages and Hemiechinus + Paraechinus. Molecular dating suggests an ancient origin of the extant gymnure lineages, which date back to the late Eocene to early Oligocene. The age of the basal split within spiny hedgehogs is relatively recent and corresponds to the Miocene–Pliocene boundary. Possible changes to the erinaceid taxonomy are considered. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 112 , 499–519.     

TERTIARY SPECIATION MODELS IN AUSTRALIAN ANURANS: MOLECULAR DATA CHALLENGE PLEISTOCENE SCENARIO

Similarities between frogs in the faunas of southwestern and southeastern Australia have long been viewed as indicators of close genetic relationships and recent (Pleistocene) divergences. We studied albumin evolution in 16 east-west species pairs of frogs representing six genera to assess the validity of these conclusions. Analysis of albumin evolution in western species of Heleioporus and some species of Litoria suggested recent speciation in these genera, with the closest sister groups occurring in the western and not among the eastern fauna. All divergences measured between eastern and western cognate species point to a Tertiary separation extending from the late Miocene to the early Oligocene. Micro-complement fixation studies provide an independent estimation of both genetic relationships between species pairs and the time of divergence of each species pair, allowing the testing of models of speciation and vicariance biogeography in a way not possible with earlier methodologies.     

Northern Hemisphere origin,transoceanic dispersal,and diversification of Ranunculeae DC. (Ranunculaceae) in the Cenozoic

Aim The role of dispersal versus vicariance for plant distribution patterns has long been disputed. We study the temporal and spatial diversification of Ranunculeae, an almost cosmopolitan tribe comprising 19 genera, to understand the processes that have resulted in the present inter‐continental disjunctions. Location All continents (except Antarctica). Methods Based on phylogenetic analyses of nuclear and chloroplast DNA sequences for 18 genera and 89 species, we develop a temporal–spatial framework for the reconstruction of the biogeographical history of Ranunculeae. To estimate divergence dates, Bayesian uncorrelated rates analyses and four calibration points derived from geological, fossil and external molecular information were applied. Parsimony‐based methods for dispersal–vicariance analysis (diva and Mesquite ) and a maximum likelihood‐based method (Lagrange ) were used for reconstructing ancestral areas. Six areas corresponding to continents were delimited. Results The reconstruction of ancestral areas is congruent in the diva and maximum likelihood‐based analyses for most nodes, but Mesquite reveals equivocal results at deep nodes. Our study suggests a Northern Hemisphere origin for the Ranunculeae in the Eocene and a weakly supported vicariance event between North America and Eurasia. The Eurasian clade diversified between the early Oligocene and the late Miocene, with at least three independent migrations to the Southern Hemisphere. The North American clade diversified in the Miocene and dispersed later to Eurasia, South America and Africa. Main conclusions Ranunculeae diversified between the late Eocene and the late Miocene. During this time period, the main oceanic barriers already existed between continents and thus dispersal is the most likely explanation for the current distribution of the tribe. In the Southern Hemisphere, a vicariance model related to the break‐up of Gondwana is clearly rejected. Dispersals between continents could have occurred via migration over land bridges, such as the Bering Land Bridge, or via long‐distance dispersal.     

Out-of-Africa again: A phylogenetic hypothesis of the genus Charaxes (Lepidoptera: Nymphalidae) based on five gene regions

Despite the long popularity of Charaxes among collectors and researchers, their evolutionary history is largely unknown. The current and accepted species groupings and relationships within the genus are based exclusively on adult morphology and life histories. Here, we examine the monophyly and evolutionary affinities of the species-groups within the genus Charaxes and explore how they relate to members of their closest genera (Euxanthe, Polyura and Palla) using 4167 bp of sequence data from five (1 mitochondrial and 4 nuclear) gene regions. Within the proposed phylogenetic framework, we estimate ages of divergence within the genus and also reconstruct their historical biogeography. We included representatives of all known species-groups in Africa and Asia, all known species of Euxanthe and Palla and two exemplar species of Polyura. We found the genus Charaxes to be a paraphyletic group with regard to the genera Polyura and Euxanthe, contrary to the earlier assumption of monophyly. We found that 13 out of 16 morphologically defined species-groups with more than one species were strongly supported monophyletic clades. Charaxes nichetes is the sister group to all the other Charaxes. Polyura grouped with the Zoolina and Pleione species-groups as a well-supported clade, and Euxanthe grouped with the Lycurgus species-group. Our results indicated that the common ancestor of Charaxes diverged from the common ancestor of Palla in the mid Eocene (45 million years ago) in (Central) Africa and began diversifying to its extant members 15 million years later. Most of the major diversifications within the genus occurred between the late Oligocene and Miocene when the global climates were putatively undergoing drastic fluctuations. A considerable number of extant species diverged from sister species during the Pliocene. A dispersal–vicariance analysis suggests that many dispersal rather than vicariance events resulted in the distribution of the extant species. The genus Polyura and the Indo-Australian Charaxes are most likely the results of three independent colonizations of Asia by African Charaxes in the Miocene. We synonymize the genera Polyura (syn. nov.) and Euxanthe (syn. nov.) with Charaxes, with the currently circumscribed Charaxes subdivided into five subgenera to reflect its phylogeny.     

Divergence time estimation in Cichorieae (Asteraceae) using a fossil-calibrated relaxed molecular clock

Knowing the age of lineages is key to understanding their biogeographic history. We aimed to provide the best estimate of the age of Cichorieae and its subtribes based on available fossil evidence and DNA sequences and to interpret their biogeography in the light of Earth history. With more than 1,550 species, the chicory tribe (Cichorieae, Asteraceae) is distributed predominantly in the northern Hemisphere, with centres of distribution in the Mediterranean region, central Asia, and SW North America. Recently, a new phylogenetic hypothesis of Cichorieae based on ITS sequences has been established, shedding new light on phylogenetic relationships within the tribe, which had not been detected so far. Cichorieae possess echinolophate pollen grains, on the surface of which cavities (lacunae) are separated by ridges. These lacunae and ridges show patterns characteristic of certain groups within Cichorieae. Among the fossil record of echinolophate pollen, the Cichorium intybus-type is the most frequent and also the oldest type (22 to 28.4 million years old). By using an uncorrelated relaxed molecular clock approach, the Cichorieae phylogenetic tree was calibrated with this fossil find. According to the analysis, the tribe originated no later than Oligocene. The species-rich core group originated no later than Late Oligocene or Early Miocene and its subtribes diversified no later than Middle/Late Miocene or Early Pliocene—an eventful period of changing geological setting and climate in the Mediterranean region and Eurasia. The first dispersal from Eurasia to North America, which resulted in the radiation of genera and species in North America (subtribe Microseridinae), also occurred no later than Middle or Late Miocene, suggesting the Bering land bridge as the route of dispersal.     

First Occurrence of Platycladus from the Upper Miocene of Southwest China and Its Phytogeographic Implications

Platycladus Spach is native to Central China, but its natural occurrences are very difficult to establish. According to molecular phylogenetic data, this genus might have originated since the Oligocene, but no fossil record has been reported. Here, we describe eight foliage branches from the upper Miocene in western Yunnan, Southwest China as a new species, P. yunnanensis sp. nov., which is characterized by foliage branches spread in flattened sprays, and leaves decussate, imbricate, scale-like and dimorphic. The leaves are amphistomatic, and the stomata are elliptical or oblong, haplocheilic, and monocyclic type. Based on a detailed comparison with the extant genera of Cupressaceae sensu lato, our fossils are classified into the genus Platycladus. The occurrence of P. yunnanensis sp. nov. indicates that this genus had a more southernly natural distribution in the late Miocene than at present. Molecular phylogeny and fossil records support a pre-Oligocene common ancestor for the genera Platycladus, Microbiota and Calocedrus. The separation of the three taxa was most likely caused by the arid belt across Central China during the Oligocene. In addition, the cooling down of the global temperature and the strengthening of Asian monsoon since the Miocene will further promote the migration of these genera.     

Out of Africa? A dated molecular phylogeny of the cicada tribe Platypleurini Schmidt (Hemiptera: Cicadidae), with a focus on African genera and the genus Platypleura Amyot & Audinet‐Serville

The Platypleurini is a large group of charismatic cicadas distributed from Cape Agulhas in South Africa, through tropical Africa, Madagascar, India and eastern Asia to Japan, with generic diversity concentrated in equatorial and southern Africa. This distribution suggests the possibility of a Gondwanan origin and dispersal to eastern Asia from Africa or India. We used a four‐gene (three mitochondrial) molecular dataset, fossil calibrations and molecular clock information to explore the phylogenetic relationships of the platypleurine cicadas and the timing and geography of their diversification. The earliest splits in the tribe were found to separate forest genera in Madagascar and equatorial Africa from the main radiation, and all of the Asian/Indian species sampled formed a younger clade nested well within the African taxa. The tribe appears to have diversified during the Cenozoic, beginning c. 50–32 Ma, with most extant African lineages originating in the Miocene or later, well after the breakup of the Gondwanan landmass. Biogeographical analysis suggests an African origin for the tribe and a single dispersal event founding the Asian platypleurines, although additional taxon sampling and genetic data will be needed to confirm this pattern because key nodes in the tree are still weakly supported. Two Platypleurini genera from Madagascar (Pycna Amyot & Audinet‐Serville, Yanga Distant) are found to have originated by late Miocene dispersal of a single lineage from Africa. The genus Platypleura is recovered as polyphyletic, with Platypleura signifera Walker from South Africa and many Asian/Indian species apparently requiring assignment to different genera, and a new Platypleura concept is proposed with the synonymization of Azanicada Villet syn.n. The genera Orapa Distant and Hamza Distant, currently listed within separate tribes but suspected of platypleurine affinity, are nested deeply within the Platypleurini radiation. The tribe Orapini syn.n . is here synonymized while the tribe Hamzini is pending a decision of the ICZN to preserve nomenclatorial stability.     

Systematics and evolutionary significance of the small Abrocomidae from the early Miocene of southern South America

Octodontoidea is the most species-rich clade among hystricomorph rodents, and has a fossil record going back to at least the late Oligocene. Affinities of fossils previous to the late Miocene differentiation of the extant families Abrocomidae, Echimyidae and Octodontidae are controversial, essentially because these fossils may share few apomorphies with modern species. In fact, pre-late Miocene representatives of Abrocomidae had not been recognised until very recently. Here we revise the early Miocene genus Acarechimys, originally assigned to Echimyidae, and alternatively to stem Octodontoidea or to Octodontidae. A systematic and parsimony-based phylogenetic analysis of the species traditionally included in Acarechimys showed that this genus is part of stem Abrocomidae. These results are primarily supported by morphology of the mandible and lower molars. Acarechimys is here restricted to three species, A. minutus, A. pulchellus and Acarechimys pascuali sp. nov., while another species, A. constans, is here transferred to a new abrocomid genus. The remaining species were nested within Octodontidae. According to these results, Abrocomidae might have been as diverse as its sister clade Octodontidae-Echimyidae during the late Oligocene–early Miocene. Extinction of this diversity would have resulted in marked loss of evolutionary history, with extant abrocomids being currently restricted to late-diverged euhypsodont representatives.     

Biases in assessing the evolutionary history of the angiosperm flora of China

In their recent paper published in Nature (2018, 554, 234‐238), Lu et al. use phylogenetic approaches to determine the proportion of the Chinese angiosperm genera that originated during the Miocene or later, and contrast divergence times and phylogenetic dispersion between eastern and western China. One of their key conclusions is that 66% of the angiosperm genera in China originated in the Miocene or later. However, an analysis of 300 angiosperm genera shows that 139 (76.8%) of the 181 genera considered as originating in the Miocene or later by Lu et al. have fossil records before the Miocene. Thus, the evolutionary history of Chinese angiosperm flora has been substantially underestimated in Lu et al. In addition, the results of Lu et al. have been biased by using an incomplete phylogeny.