CHLORANTHUS-LIKE STAMENS FROM THE UPPER CRETACEOUS OF NEW JERSEY

Fossil angiospermous stamens with in situ pollen from the Turonian (ca. 90 million years before present, Late Cretaceous) of New Jersey are described and assigned to the Chloranthaceae. The fossil stamens, which are three-parted and bear two bisporangiate thecae on the central lobe and one bisporangiate theca on each lateral lobe, are indistinguishable from stamens of several extant species of Chloranthus. The pollen is spheroidal, 13–18 μm in diameter, with a reticulate exine and apparently elongate/elliptical apertures. The pollen is similar to that in extant Chloranthus in grain size, shape, exine sculpture, and aperture structure. Like pollen of some extant species of Chloranthus, aperture number in the fossil pollen appears to be variable. Because fossil pistillate chloranthoid reproductive structures have not been found at this locality it is unknown whether the fossil stamens described here were borne on the side of the ovary, as in extant Chloranthus, or in another arrangement. The three-parted stamen of Chloranthus is unique in angiosperms and there has been considerable debate concerning the origin and evolutionary significance of the structure. Uncertainty as to whether the three-parted stamen represents a synapomorphy for the genus or a retained plesiomorphy in angiosperms is the primary reason why these fossil stamens are not assigned to the extant genus Chloranthus.     

Three terrestrial Pleistocene coucals (Centropus: Cuculidae) from southern Australia: biogeographical and ecological significance

Coucals are large, predatory, primarily ground‐dwelling cuckoos of the genus Centropus, with 26 extant species ranging from Africa to Australia. Their evolutionary and biogeographical history are poorly understood and their fossil record almost non‐existent. Only one species (Centropus phasianinus) currently inhabits Australia, but there is now fossil evidence for at least three Pleistocene species. One of these (Centropus colossus) was described from south‐eastern Australia in 1985. Here we describe additional elements of this species from the same site, and remains of two further extinct species from the Thylacoleo Caves of the Nullarbor Plain, south‐central Australia. The skeletal morphology and large size of the three extinct species indicates that they had reduced capacity for flight and were probably primarily ground‐dwelling. The extinct species include the two largest‐known cuckoos, weighing upwards of 1 kg each. They demonstrate that gigantism in this lineage has been more marked in a continental context than on islands, contrary to the impression gained from extant species. The evolutionary relationships of the Australian fossil coucals are uncertain, but our phylogenetic analysis indicates a possible close relationship between one of the Nullarbor species and extant Centropus violaceus from the Bismarck Archipelago. The presence of three coucals in southern Australia markedly extends the geographical range of the genus from tropical Australia into southern temperate regions. This demonstrates the remarkable and consistent ability of coucals to colonize continents despite their very limited flying ability.     

Fossil Araceae from a Paleocene neotropical rainforest in Colombia

Both the fossil record and molecular data support a long evolutionary history for the Araceae. Although the family is diverse in tropical America today, most araceous fossils, however, have been recorded from middle and high latitudes. Here, we report fossil leaves of Araceae from the middle-late Paleocene of northern Colombia, and review fossil araceous pollen grains from the same interval. Two of the fossil leaf species are placed in the new fossil morphogenus Petrocardium Herrera, Jaramillo, Dilcher, Wing et Gomez-N gen. nov.; these fossils are very similar in leaf morphology to extant Anthurium; however, their relationship to the genus is still unresolved. A third fossil leaf type from Cerrejón is recognized as a species of the extant genus Montrichardia, the first fossil record for this genus. These fossils inhabited a coastal rainforest ～60-58 million years ago with broadly similar habitat preferences to modern Araceae.     

澳大利亚轮藻植物LYCHNOTHAMNUS BARBATUS(MEYEN)LEONHARDI藏卵器统计分析及与欧洲同类植物的对比研究

Lychnothamnus(Characeae)为一分布于欧洲和大洋洲的单型属,该类植物日趋衰落。过去十年中,仅在澳大利亚昆士兰州华莱士湾发现数量丰富生长良好的L．barbatus(Meyen)Leonhardi。本文对澳大利亚现生L．barbatus藏卵器进行描述、统计分析和扫描照相,并与其它地区同类现生和化石藏卵器进行对比,结果表明澳大利亚的藏卵器除形状偏长球形、宽度较小、钙化较弱外,其余特征与欧洲植物较为一致。钙化减弱的原因可能与澳大利亚热带地区由季风造成的洪水泛滥降低了水体中离子的浓度有关。     

Former diversity of Ephedra (Gnetales): evidence from Early Cretaceous seeds from Portugal and North America

BACKGROUND AND AIMS: The extant species of the seed plant group Gnetales (Ephedra, Gnetum and Welwitschia) have been considered a remnant of a much greater, now extinct, diversity due to the pronounced differences in form and ecology among the genera. Until recently, this hypothesis has not been supported by evidence from the fossil record. This paper adds to the expanding information on Gnetales from the Early Cretaceous and describes coalified seeds from Barremian-Albian localities in Portugal and USA. METHODS: The fossils were extracted from sediment samples by sieving in water. Adhering mineral matrix was removed by chemical treatment. Seeds were investigated using light and scanning electron microscopy. Morphology and anatomy of the seeds were documented and compared with those of extant species. KEY RESULTS: The fossils share characters with extant Ephedra, for example papillae on the inner surface of the seed envelope and in situ polyplicate pollen grains that shed the exine during germination. They differ from extant Ephedra seeds in morphological and anatomical details as well as in their smaller size. Two new species of Ephedra are described together with one species assigned to a new genus of Gnetales. Other Ephedra-like seeds, for which pollen and critical morphological details are currently unknown, are also present in the samples. CONCLUSIONS: These Cretaceous seeds document that key reproductive characters and pollen germination processes have remained unchanged within Ephedra for about 120 million years or more. There is sufficient variety in details of morphology to suggest that a diversity of Ephedra and Ephedra-like species were present in the Early Cretaceous flora. Their presence in Portugal and eastern North America indicates that they were widespread on the Laurasian continent. The fossil seeds are similar to seeds of Erdtmanithecales and this supports the previously suggested relationship between Erdtmanithecales and Gnetales.     

The earliest fossil evidence of the Hamamelidaceae: Late Cretaceous (Turonian) inflorescences and fruits of Altingioideae

Fossilized pistillate inflorescences, fruits, and pollen grains from the Turonian (～90 million years before present) of New Jersey are described as a new genus, Microaltingia, in the family Hamamelidaceae. The fossils are remarkably preserved in exceptional detail. Several morphological and anatomical characters suggest affinities with Hamamelidaceae. These include capitate inflorescences, florets with a hypanthium, two-carpellate gynoecia, perigynous flowers, tricolpate reticulate pollen, a three-layered carpel wall, scalariform perforation plates with oblique end walls, and scalariform and opposite/alternate intervascular pitting. The gross morphology of pistillate inflorescences, unisexual flowers, phyllome structure, numerous ovules per carpel, and mode of carpel dehiscence indicate affinities with subfamily Altingioideae, which includes the modern genera Liquidambar and Altingia. Cladistic analysis using a previously published morphological matrix and scoring the fossil for available characters supports the position of the fossil as a sister taxon of modern Altingioideae. Although the fossil exhibits a mosaic of characters found within modern Hamamelidaceae, it is not identical to any modern taxon. Based on cladistic analysis, the fossil appears to be a basal "altingioid" that lacks the derived pollen found in extant Altingioideae and retains the more plesiomorphic tricolpate pollen found in the rest of Hamamelidaceae. The floral characters of the fossils, including phyllomes with stomata, short and straight styles, and small perprolate pollen grains, also indicate the possibility of insect pollination.     

Cretaceous and Eocene fossils of the rare extant genus Synneuron Lundstrom (Diptera: Canthyloscledidae): evidence of a true Pangean clade

The first two fossil species of the canthyloscelid genus Synneuron are described based on compression wings. Synneuron eomontana sp. nov. is described from the Middle Eocene Coal Creek Member of the Kishenehn Formation, in the USA, and Synneuron jelli sp. nov. is described from the Lower Cretaceous Koonwarra Fossil Bed of the Korumburra Group, in Australia. The wings are illustrated and compared to the extant species of the genus, to species of the three other recent genera of Canthyloscelidae and to an anisopodid. A phylogenetic analysis of the relationships between the species of Synneuron was performed. The Eocene fossil S. eomontana appears as sister of the pair of recent Holarctic species of the genus, while the Australian Cretaceous species S. jelli is sister of the clade with the species of Synneuron of the northern hemisphere. The sister group of Synneuron is the canthyloscelid clade (Hyperoscelis + Canthyloscelis), for which a middle Jurassic fossil is known. At the early Cretaceous, Gondwana was already separated from Laurasia and the disjunction between the species of Synneuron in Australia and the northern hemisphere clade of the genus suggest a true pangeic origin for the genus. The biology of the canthyloscelid larvae is shaped by its trophic specialization—xylosaprophagous. This suggests that the transition from the Pangean Jurassic gymnosperm-dominated forests to the late Cretaceous angiosperm-dominated forests may be related to the low recent diversity of Synneuron or of the canthyloscelids in the world—and maybe to the extinction of the genus in the southern hemisphere. This major turnover of the vegetation type along the Cretaceous may be also somehow related to the complete extinction of other groups of flies strictly associated with gymnosperms, as may be the case of the lower brachyceran family Zhangsolvidae. This speculation needs additional corroboration from other groups, that will become available with the combination of systematics, paleontology and biogeographical information of different early Cretaceous clades.     

Geometric morphometric analyses of worn cheek teeth help identify extant and extinct gophers (Rodentia,Geomyidae)

Studies of the biostratigraphy and palaeoecology of fossil vertebrate assemblages require large samples of accurately identified specimens. Such analyses can be hampered by the inability to assign isolated and worn remains to specific taxa. Entoptychine gophers are a diverse group of burrowing rodents found in Oligo‐Miocene deposits of the western United States. In both entoptychines and their extant relatives the geomyines, diagnostic characters of the occlusal surface of the teeth are modified with wear, making difficult the identification of many isolated fossil teeth. We use geometric morphometrics to test the hypothesis that tooth shape informs taxonomic affinities and expected levels of morphological variation across gopher taxa. We also incorporate data from microcomputer tomography to investigate changes in occlusal surface shape through wear within individuals. Our analyses demonstrate the usefulness of our approach in identifying extant geomyines to the genus, subgenus and species levels, and fossil entoptychines to the genus and, in some cases, the species level. Our results cast doubt on the validity of some species within Entoptychus and suggest future revisions to entoptychine taxonomy. The amounts of morphological divergence observed among fossil and extant genera are similar. Fossil species do not differ greatly from extant ones in that regard either. Further work evaluating the morphological variation within and across entoptychine species, including unworn teeth and osteological material, will allow revised analyses of the biostratigraphy and palaeoecology of important Oligo‐Miocene mammalian assemblages of the western United States and help to infer the phylogenetic relationships and evolution of gophers.     

LYCHNOTHAMNUS BARBATUS(轮藻植物)的生态与保护研究

轮藻植物属Lychnothamnus(Rupr．)Leonh．自晚始新世即有化石代表,在上新世繁盛且分布广泛,此后分异度降低、分布范围缩减,延续至今仅存1种：L．barbatus(Meyen)Leonh．。上世纪末叶前该种还曾广泛分布于欧洲、印度、中国、巴布亚新几内亚和澳大利亚,而后该种在澳大利亚曾经留有记录的产地消失,直到1996年才被再次发现。本文描述了澳大利亚L．barbatus的居群特征,包括植株、卵囊球和藏卵器形态特征以及萌发生态学的实验研究结果。讨论该种的野外生态学、共生种、全球范围的分布与丰度特征,探讨该种衰落的原因并提出植物保护方案。     

Phylogeny of the North American catfish family Ictaluridae (Teleostei: Siluriformes) combining morphology,genes and fossils

We performed the first combined‐data phylogenetic analysis of ictalurids including most living and fossil species. We sampled 56 extant species and 16 fossil species representing outgroups, the seven living genera, and the extinct genus ?Astephus long thought to be an ictalurid. In total, 209 morphological characters were curated and illustrated in MorphoBank from published and original work, and standardized using reductive coding. Molecular sequences harvested from GenBank for one nuclear and four mitochondrial genes were combined with the morphological data for total evidence analysis. Parsimony analysis recovers a crown clade Ictaluridae composed of seven living genera and numerous extinct species. The oldest ictalurid fossils are the Late Eocene members of Ameiurus and Ictalurus. The fossil clade ?Astephus placed outside of Ictaluridae and not as its sister taxon. Previous morphological phylogenetic studies of Ictaluridae hypothesized convergent evolution of troglobitic features among the subterranean species. In contrast, we found morphological evidence to support a single clade of the four troglobitic species, the sister taxon of all ictalurids. This result holds whether fossils are included or not. Some previously published clock‐based age estimates closely approximate our minimum ages of clades.     

Early Oligocene Callitris and Fitzroya (Cupressaceae) from Tasmania

This paper documents Early Oligocene fossilized foliage and ovulate cones from Lea River, Tasmania and identifies them as belonging to two extant southern hemisphere Cupressaceae genera, Callitris and Fitzroya. Most importantly, it sheds some light on evolutionary trends within Callitris, a genus with numerous extant Australian species and two extant New Caledonian species. Callitris has a very poor fossil record and, because of the present absence of a molecular data set that includes all species, its phylogeny remains somewhat ambiguous. Although Fitzroya foliage has previously been described from a number of Tasmanian sites, this is the first recording of fertile material. The ovulate cones of the Callitris and Fitzroya macrofossils are characterized by bract-scale complexes in two whorls of three and are subtended by scale-like leaves in whorls of three. The fossilized foliage specimens consist of scale-like leaves in whorls of three. These morphological characteristics are only exhibited by three extant southern hemisphere cupressaceous genera, Callitris, Actinostrobus, and Fitzroya. The assignment of the fossils to extinct Callitris and Fitzroya species is made by comparisons with species from these three extant genera. Although much of the Lea River flora are wet rainforest taxa, the Callitris fossils have characteristics of both wet- and dry-adapted extant species.     

A survey of species assigned to the fossil pollen genus Anacolosidites

Anacolosidites Cookson & Pike, a fossil pollen genus recorded since the Campanian, is peculiar in its morphology – six‐porate with three apertures on each hemisphere, located away from the equator, and with the distal and proximal apertures positioned over each other. Representatives of this fossil genus are widely considered to represent extant Olacaceae from tribe Anacoloseae. Olacaceae is an exclusively tropical angiosperm family with a pantropical distribution; consequently the fossils are often used to suggest a tropical climate and in addition are frequently used as a stratigraphic marker. Fossil species assigned to Anacolosidites are quite variable and may not all represent Olacaceae, in which case they may not indicate tropical climate.

The present study is a morphological survey of fossil pollen assigned to Anacolosidites; it identifies the published reports of the fossil species that probably represent positive occurrences of Olacaceae pollen in the fossil record. Within Olacaceae, Anacolosidites‐type pollen is usually compared with pollen of genera in tribe Anacoloseae, in particular: Cathedra, Anacolosa and Phanerodiscus, but never with the pollen of Ptychopetalum, a genus from tribe Olaceae with closely similar pollen to the other three genera, but with a reticulate tectum and very small circular apertures located near the equator. Nevertheless, the records of reticulate Anacolosidites species which have been excluded from the emended diagnosis are unlikely to be related to Ptychopetalum. The earliest accepted record of Anacolosidites is from the Late Cretaceous (Maastrichtian) of Germany. However, most Late Cretaceous records, and later Russian and Chinese occurrences referred to Anacolosidites, consist mainly of Normapolles‐type pollen, whereas many of the Cenozoic records assigned to Anacolosidites have a much clearer affinity with the pollen of Anacolosa, Cathedra and Phanerodiscus (tribe Anacoloseae). The newly emended genus Anacolosidites may be used as a stratigraphic marker for tropical or megathermal climatic conditions.     

Pollen morphology and fossil record of the feathery mistletoe family Misodendraceae

Misodendraceae is a small family of mistletoes in the order Santalales. Its distribution is restricted to the southern South American temperate forests. The family comprises the sole genus Misodendrum with eight species of hemiparasitic shrubs, mainly parasitising the southern beech Nothofagus. This contribution presents palynological evidence from seven species, using light microscopy and scanning electron microscopy. Pollen grains are consistently small, periporate and echinate, although differences in the length of echini and number and size of pores were noted. Pollen features can be used to distinguish groups of species and, in some cases, individual species. Cluster analysis of pollen characters differentiates two main groups: one includes M. brachystachyum, M. oblongifolium and M. quadriflorum; and the other includes M. gayanum, M. linearifolium, M. punctulatum and M. angulatum. Palynological results are compared with previous systematic studies of the family. The South American fossil pollen record is summarised and characters of the fossil pollen are analysed using UPGMA to test the relationships between extant and fossil species. Miocene pollen resulted similar to species of subgenus Angelopogon while Eocene pollen is disimilar to extant species of Misodendraceae.     

Systematics of Nothofagus (Nothofagaceae) based on rDNA spacer sequences (ITS): taxonomic congruence with morphology and plastid sequences

Phylogenetic relationships were examined within the southern beech family Nothofagaceae using 22 species representing the four currently recognized subgenera and related outgroups. Nuclear ribosomal DNA sequences encoding the 5.8s rRNA and two flanking internal transcribed spacers (ITS) provided 95 phylogenetically informative nucleotide sites from a single alignment of ~588 bases per species. Parsimony analysis of this variation produced two equally parsimonious trees supporting four monophyletic groups, which correspond to groups designated by pollen type. These topologies were compared to trees from reanalyses of previously reported rbcL sequences and a modified morphological data set. Results from parsimony analysis of the three data sets were highly congruent, with topological differences restricted to the placement of a few terminal taxa. Combined analysis of molecular and morphological data produced six equally parsimonious trees. The consensus of these trees suggests two basal clades within Nothofagus. Within the larger of the two clades, tropical Nothofagus (subgenus Brassospora) of New Guinea and New Caledonia are strongly supported as sister to cool-temperate species of South America (subgenus Nothofagus). Most of the morphological apomorphies of the cupule, fruit, and pollen of Nothofagus are distributed within this larger clade. An area cladogram based on the consensus of combined data supports three trans-Antarctic relationships, two within pollen groups and one between pollen groups. Fossil data support continuous ancestral distributions for all four pollen groups prior to continental drift; therefore, vicariance adequately explains two of these disjunctions. Extinction of trans-Antarctic sister taxa within formerly widespread pollen groups explains the third disjunction; this results in a biogeographic pattern indicative of phylogenetic relationship not vicariance. For the biogeographically informative vicariant clades, area relationships based on total evidence support the recently advanced hypothesis that New Zealand and Australia share a unique common ancestry. Contrary to previous thought, the distribution of extant Nothofagus is informative on the area relationships of the Southern Hemisphere, once precise phylogenetic relationships are placed in the context of fossil data.     

Diverse fossil Onagraceae pollen from a Miocene palynoflora of north-east China: early steps in resolving the phytogeographic history of the family

The origin and evolution of angiosperms can be unravelled by using fossil records to determine first occurrences and phytogeographic histories of plant families and genera. Many angiosperm families, for example the Onagraceae, have a poor macrofossil record, but are more common in palynological records. Modern Onagraceae produce pollen clearly distinct from that of other angiosperms. Combined morphological features obtained by use of light and scanning electron microscopy have enabled assignment of fossil Onagraceae pollen to extant genera, and therefore tracing of the origin and past distributions of extant Onagraceae lineages. We studied a Miocene palynoflora from the Daotaiqiao Formation of north-east China. Using the single-grain technique, we examined individual Onagraceae pollen/tetrads using both light and scanning electron microscopy. Fossil Onagraceae pollen is more frequent than macrofossil remains, but is still rare, and usually represented by a single taxon in palynological samples. Remarkably, samples from the Miocene of north-east China contain five different species: two of Circaea, one of Epilobium, and two of Ludwigia. Such a large number of Onagraceae taxa from a single palynoflora is unknown elsewhere. Whereas Ludwigia pollen is known from Cenozoic sediments of the northern hemisphere, the Circaea pollen is the first fossil pollen assignable to this extant genus. This is also the first fossil record of Epilobium from China. Although the young geological age of this sample does not enable consideration of time of origin for the genera encountered, the co-occurrence of Circaea, Epilobium, and Ludwigia in the mid to late-Miocene of East Asia sheds some light on their phytogeographic histories.     

BOTANICAL AFFINITIES OF SOME TRIPROJECTACITES FOSSIL POLLEN

During Late Cretaceous to Oligocene times, fossil pollen of the Triprojectacites group (also known as Aquilapolles or triprojectates), comprised a temporally and environmentally distinctive element of palynofloras in eastern Asia and western North America. Several species of this group serve as biostratigraphic index fossils for this interval. Using electron microscope and numerical analyses, primarily of North American triprojectate pollen, it is possible to recognize the presence of three distinct subgroups. One group, corresponding to the fossil genus Mancicorpus, has no morphologically close modern representative. Characters resembling those in Santalaceae (Santalales, Rosidae) occur in the second group, which is represented by a previously underscribed fossil triprojectate genus. The third group contains retipilate, isopolar pollen and strioreticulate, isopolar pollen. Forms exhibiting the latter morphology are commonly assigned to the genus Integricorpus, while the retipilate morphology characterizes another underscribed genus. This third group may have some phylogenetic connection to Apiaceae (Apiales, Asteridae). Pollen of some other extant families exhibits triprojectate features, although no close fossil representative can be presently identified. The triprojectate morphology is thus interpreted in modern and fossil forms as resulting from convergence rather than close phylogenetic relationships at the group level.     

Elatides sandaolingensis n. sp. (Cupressaceae sensu lato) — A new fossil conifer with cones from the Middle Jurassic of Xinjiang,northwestern China

Here we describe a new conifer fossil, Elatides sandaolingensis Z.X. Wang and B.N. Sun n. sp., from the Middle Jurassic Xishanyao Formation in the Turpan-Hami Basin, Xinjiang Uygur Autonomous Region, northwestern China. The materials consist of compressions represented by well-preserved leafy shoots, pollen cones, and seed cone. Leaves are characterized by long triangular shapes, with straight apex and entire margins, and two stomatal bands on the abaxial surface. Pollen cones are terminally disposed on the ultimate leafy shoots, borne singly or in clusters. Pollen sacs are long-oval shaped, with three pollen sacs fused together. Pollen grains are spherical and have small germinal papilla and few wrinkles. The seed cone is oblong, with more than 35 helically arranged bract-scale complexes, which are characterized by long-oval shape and triangular apex. Compared with the extant nine genera of Taxodiaceous Cupressaceae in the morphology of seed cone and pollen cones, the present fossil consistently shares many characteristics with the extant genus Cunninghamia, but differs in other aspects. After being compared with the reported fossil records of the fossil plants, the current species is found to be different from any known species; thus, the present fossil is referred to as a new species of Elatides. From the similarity between the present fossil and Cunninghamia, it can be inferred that there may be a genetic relationship between these two genera. Additionally, the new species has thin cuticles and slightly sunken stomata, which can provide evidence indicating that the climate of the Turpan-Hami Basin in Middle Jurassic might have been warm and humid. By studying the geological history and geographical distribution of Elatides, it can be inferred that this genus may have originated in Switzerland, and it was migrated from Xinjiang to North and South China through the Ural Mountains.     

Fossil legumes from the Middle Eocene (46.0 Ma) Mahenge Flora of Singida, Tanzania

Middle Eocene age caesalpinioid and mimosoid legume leaves are reported from the Mahenge site in north-central Tanzania. The Mahenge flora complements a sparse Paleogene tropical African fossil plant record, which until now consisted of a single macrobotanical assemblage, limited palynological studies in West Africa and Egypt, and fossil wood studies primarily from poorly dated deposits. Mahenge leaf macrofossils have the potential to add significantly to what is known of the evolutionary history of extant African plant groups and to expand our currently limited knowledge of African Paleogene environments. The site is associated with a kimberlite eruption and demonstrates the potential value of kimberlite-associated lake deposits as much-needed resources for African Paleogene floras. In this report we document a relatively diverse component of the flora consisting of the leaves of at least five species of Leguminosae. A new species of the extant genus Acacia (Mimosoideae), described herein, is represented by a bipinnate leaf. Another taxon is described as a new species of the extant genus Aphanocalyx (Caesalpinioideae), and a third leaf type may be related to the extant genus Cynometra (Caesalpinioideae). Two additional leaf types are less well understood: one appears to be referable to the Caesalpinioideae and subfamily affinities of the other taxon are unknown.