ARIADNAESPORITES AND GLOMERISPORITES IN THE LATE CRETACEOUS: ANCESTRAL SALVINIACEAE

Glomerisporites and Ariadnaesporites are two genera based on megaspores and microspores from the late Cretaceous. Each has megaspores with characteristics shared with other late Cretaceous Salviniaceae, including numerous floats, an acrolamella, and a complex perispore. Microspores are borne singly, however, not in characteristic salviniaceous massulae. Microspores of Glomerisporites have a pseudovacuolate basal region and a single spore in an apical neck. Microspores of Ariadnaesporites are structurally like the megaspores but of smaller size. Ariadnaesporites varius occurs in the Cenomanian Stage (early late Cretaceous) and is the oldest presumed member of the Salviniaceae.     

STUDIES ON FOSSIL AZOLLA: PRIMITIVE TYPES OF MEGASPORES AND MASSULAE FROM THE CRETACEOUS

Fossil Salviniaceae are described from the Claggett Shale and Judith River Formation, late Cretaceous (Campanian stage) of Montana. A new genus, Parazolla, from the Claggett Shale, has megaspores in which the swimming apparatus is composed of a number of elongate floats attached to the megaspore body and invested by coiled hairs. The floats separate at maturity. Massulae (bearing microspores) have simple hair-like glochidia, many of which are knobbed at their tips. Glochidia tend to resemble the perisporial hairs of the megaspore body. This resemblance provides fossil evidence of the homology of these two hair-like structures among living species of Azolla. In Azolla simplex from the Judith River Formation the megaspore has a single cap-like so-called columellate float. Massulae, which have anchor-shaped glochidia, are associated with these megaspores. A. simplex is the oldest species of Azolla and Parazolla the oldest member of the Salviniaceae so far found.     

The role of Hydropteris pinnata gen. et sp. nov. in reconstructing the cladistics of heterosporous ferns

Large segments of intact plants that represent a heterosporous fern have been discovered within an aquatic plant community from the Late Cretaceous St. Mary River Formation near Cardston in southern Alberta, Canada. Branching rhizomes of Hydropteris pinnata gen. et sp. nov. are 1–2 mm wide. They produce fronds at intervals of 2–12 mm and bear numerous elongated roots. Fronds, up to approximately 6 cm long, are pinnate with subopposite to alternate pinnae that exhibit anastomosing venation. Large, multisoral sporocarps occur at the junctures of the rhizome and frond rachides. Both microsporangiate massulae and megaspore complexes occur within each sporocarp. Megaspore complexes are assignable to the sporae dispersae genus Parazolla Hall. Microspores are trilete, smooth-walled, and are embedded in episporal material of the massulae. A numerical cladistic analysis indicates that the heterosporous aquatic ferns are monophyletic, and not as closely related to either schizaeaceous or hymenophyllaceous ferns as they are to some other filicaleans. Systematic revisions are proposed to reflect newly recognized cladistic relationships within the heterosporous clade, and character originations in the evolution of heterosporous aquatic ferns are evaluated. Hydropteridaceae fam. nov. is proposed, and included with Salviniaceae and Azollaceae in the Hydropteridineae subord. nov., and the Hydropteridales Willdenow.     

Late Cretaceous Aquatic Plant World in Patagonia,Argentina

In this contribution, we describe latest Cretaceous aquatic plant communities from the La Colonia Formation, Patagonia, Argentina, based on their taxonomic components and paleoecological attributes. The La Colonia Formation is a geological unit deposited during a Maastrichtian-Danian transgressive episode of the South Atlantic Ocean. This event resulted in the deposition of a series of fine-grained sediments associated with lagoon systems occurring along irregular coastal plains in northern Patagonia. These deposits preserved a diverse biota, including aquatic and terrestrial plants and animals. The aquatic macrophytes can be broadly divided into two groups: free-floating and rooted, the latter with emergent or floating leaves. Free-floating macrophytes include ferns in Salviniaceae (Azolla and Paleoazolla) and a monocot (Araceae). Floating microphytes include green algae (Botryoccocus, Pediastrum and Zygnemataceae). Among the rooted components, marsileaceous water ferns (including Regnellidium and an extinct form) and the eudicot angiosperm Nelumbo (Nelumbonaceae) are the dominant groups. Terrestrial plants occurring in the vegetation surrounding the lagoons include monocots (palms and Typhaceae), ferns with affinities to Dicksoniaceae, conifers, and dicots. A reconstruction of the aquatic plant paleocommuniy is provided based on the distribution of the fossils along a freshwater horizon within the La Colonia Formation. This contribution constitutes the first reconstruction of a Cretaceous aquatic habitat for southern South America.     

Ultrastructural interpretation of the Late Cretaceous megaspore Glomerisporites pupus and its associated microspores

The ultrastructure of the Late Cretaceous (Santonian–?early Campanian) megaspore Glomerisporites pupus and its associated microspores has been examined in an attempt to resolve a number of problems concerning the interpretation of their morphology. The new observations presented are based on an analysis of entire, fragmentary, and thin-sectioned specimens under scanning and transmission electron microscopes. These add to, and partly correct, previous observations on this taxon. They include the following: (1) The exine of the megaspore consists of thin, homogeneous, outer undulating and inner electron dense layers, with a thicker zone of spongy structure in-between. (2) The perispore (or perine) of the megaspore comprises four layers, in order towards the exterior: loose filamentous, dense filamentous, vacuolate, and columnar. (3) This is completely enclosed by a thick mat of hairs, which appears to be attached to the underlying perisporal layers by means of connections with a few of the “spines” that originate from the dense filamentous zone, and with some elements of the columnar perine. (4) The tripartite neck (acrolamella) of the spore, which is hidden beneath the mat of hairs, is predominantly an extension of the dense filamentous and vacuolate layers, but also involves the columnar layer, especially in the lower part. (5) Some of the numerous small floats that are embedded in the mat have hairs originating from them. (6) Both long tangled and circinate hairs surround the perispore of the microspores. (7) The exine of the microspore was at least partly attached to the perispore when the organ was viable. (8) It comprises four zones that vary in structure and electron density. These facts and comparisons made with other megaspores and their associated microspores confirm evolutionary links between G. pupus and several taxa included within the Salviniaceae (Azolla, Parazolla, Salvinia) and possible ancestors of this group (the parent plants of Ariadnaesporites and Capulisporites).     

Assessing phylogenetic relationships in extant heterosporous ferns (Salviniales), with a focus on Pilularia and Salvinia

Heterosporous ferns (Salviniales) are a group of approximately 70 species that produce two types of spores (megaspores and microspores). Earlier broad‐scale phylogenetic studies on the order typically focused on one or, at most, two species per genus. In contrast, our study samples numerous species for each genus, wherever possible, accounting for almost half of the species diversity of the order. Our analyses resolve Marsileaceae, Salviniaceae and all of the component genera as monophyletic. Salviniaceae incorporate Salvinia and Azolla; in Marsileaceae, Marsilea is sister to the clade of Regnellidium and Pilularia– this latter clade is consistently resolved, but not always strongly supported. Our individual species‐level investigations for Pilularia and Salvinia, together with previously published studies on Marsilea and Azolla (Regnellidium is monotypic), provide phylogenies within all genera of heterosporous ferns. The Pilularia phylogeny reveals two groups: Group I includes the European taxa P. globulifera and P. minuta; Group II consists of P. americana, P. novae‐hollandiae and P. novae‐zelandiae from North America, Australia and New Zealand, respectively, and are morphologically difficult to distinguish. Based on their identical molecular sequences and morphology, we regard P. novae‐hollandiae and P. novae‐zelandiae to be conspecific; the name P. novae‐hollandiae has nomenclatural priority. The status of P. americana requires further investigation as it consists of two geographically and genetically distinct North American groups and also shows a high degree of sequence similarity to P. novae‐hollandiae. Salvinia also comprises biogeographically distinct units – a Eurasian group (S. natans and S. cucullata) and an American clade that includes the noxious weed S. molesta, as well as S. oblongifolia and S. minima. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 157 , 673–685.     

Ichnologic note

Palaxius salataensis, an anomuran microcoprolite, is described from Cretaceous deposits of the MIT Guyot in the northwest Pacific, about 1500 km southeast of Japan. This is the first report of the ichnogenus in this area and the first report of the ichnospecies in Cretaceous deposits. The range of P. salataensis is thus very long, from Permian to Cretaceous.     

The incertae sedis <Emphasis Type="Italic">Carpathoporella</Emphasis> Dragastan, 1995, from the Lower Cretaceous of Albania: skeletal elements (sclerites,internodes/branches,holdfasts) of colonial octocorals

The incertae sedis Carpathoporella Dragastan, 1995, reported from the Lower Cretaceous of the Western Tethyan domain, is usually interpreted as remains of calcareous algae (Dasycladales or Characeae). New thin-section material from the Aptian of Albania sheds light not only on its biogenic nature but also on the morphological variability of this taxon. In fact, Carpathoporella represents the debris of colonial, bushy, most likely gorgonid octocorals with tuberculated spheroids that may be fused at least near the basal root-like holdfast. Colony branching originates from longitudinally grooved calcareous branches or internodes. Possible relationships to other Upper Cretaceous to Palaeogene genera are discussed and a revised critical inventory of Cretaceous octocorals is presented. Due to the evidenced morphological features, Carpathoporella could either represent an ancestral isidid octocoral of the order Alcyonacea such as Moltkia Steenstrup or, due to the likely primary aragonitic skeletal mineralogy, a representative of Epiphaxum Lonsdale of the order Helioporacea. Due to morphological analogies, the new combination Carpathoporella elliotti (Radoičić) is proposed. In any case, the Lower Cretaceous record from Tethyan peri-reefal shallow-water carbonates is highlighted since numerous skeletal findings of fossil gorgonid Octocorallia were so far only known from Upper Cretaceous and younger strata of outer shelf environments of the boreal realm. The origin of deep-water Upper Cretaceous octocorals from Lower Cretaceous shallow-water taxa such as Carpathoporella is proposed as a possible further example of onshore/offshore evolutionary pattern.     

The origins of modern nonmarine ostracod faunas: evidence from the Late Cretaceous and Early Palaeogene of Mongolia

The Cretaceous and Tertiary development of Mongolian non-marine ostracod faunas is reviewed. During the Late Cretaceous and Early Palaeogene, representatives of the Cypridoidea were widespread and common, Cytheroidea less so and the Darwinuloidea comparatively rare. The evolutionary history of the subfamily Talicyprideinae is considered, with reference to the genera Talicypridea, Altanicypris, Khandiaand Bogdocypris. It is suggested that the extinct Talicyprideinae were related to the mid-Cretaceous to Recent subfamily Cypridinae (e.g. the genus Cypris), both belonging to the family Cyprididae. It is shown that early representatives of the Cyprididae, one of the most diverse non-marine cypridoidean families today, were present from Early Cretaceous onwards (e.g. Lycopterocypris, Mongolocypris), alongside the dominant Cretaceous cypridoideans, the Cyprideidae (e.g. Cypridea), which became extinct in the Palaeogene.     

PINUS TRIPHYLLA AND PINUS QUINQUEFOLIA FROM THE UPPER CRETACEOUS OF MASSACHUSETTS

Dwarf shoots and needle leaves of Pinus triphylla Hollick and Jeffrey and P. quinquefolia Hollick and Jeffrey have been discovered recently in a Late Cretaceous age clay deposit on Martha's Vineyard Island, Massachusetts. Detailed study of these fossils provides further information on the internal construction of the two taxa. This new information permits both species to be compared easily with similar fossil forms from the Upper Cretaceous of Japan as well as with dwarf shoots and needles of modern species of Pinus. As a result, the relationships between Cretaceous pines and the extinct genus Prepinus are found to be less than previously believed. Moreover, the dwarf shoots and needles of Cretaceous members of the genus Pinus appear to be most like those of present-day species included in the subgenus Pinus.     

Phase contrast X‐ray synchrotron microtomography and the oldest damselflies in amber (Odonata: Zygoptera: Hemiphlebiidae)

Electrohemiphlebia barucheli gen. et sp. nov. and Jordanhemiphlebia electronica gen. et sp. nov. , two new genera and species are described, based on exceptional inclusions of hemiphlebiid damselflies in Cretaceous amber from France and Jordan. The type specimen of E. barucheli was studied using phase contrast X‐ray synchrotron microtomography, giving exceptional images and detailed information. Its comparison with the recent Hemiphlebia mirabilis confirms the attribution of several Cretaceous damselflies to the Hemiphlebiidae, showing that this particular group was widespread in the Early Cretaceous and probably originated in the Late Jurassic or earlier. The ecological niches today occupied by the small coenagrionoid damselflies were occupied during the Triassic and Jurassic by Protozygoptera, hemiphlebiids during the Early Cretaceous, and modern taxa in the Cenozoic.     

A second hadrosauroid dinosaur from the early Late Cretaceous of Zuoyun,Shanxi Province,China

A second basal hadrosauroid dinosaur, Zuoyunlong huangi gen. et sp. nov., is reported from the early Late Cretaceous Zhumapu Formation in Zuoyun County, Shanxi Province, northern China. Zuoyunlong preserves a partial right ilium and ischium and is unique in having a very short postacetabular process 50% as long as the iliac central plate. Our cladistic analysis recovers Zuoyunlong as the most basal Late Cretaceous hadrosauroid, with a sister taxon relationship with Probactrosaurus from the late Early Cretaceous of Inner Mongolia. Including Zuoyunlong, four Cenomanian basal hadrosauroids have been recorded, and the two taxa in North America (Eolambia and Protohadros) represent the earliest known hadrosauroids outside of Asia. In the light of the proposed phylogenetic topology and biogeographic data, the discovery of Zuoyunlong indicates that the first dispersal of hadrosauroids from Asia to North America probably happened around the boundary between the Early and Late Cretaceous.     

Review of Japanese Dinosaur Track Localities: Implications for Ichnotaxonomy,Paleogeography and Stratigraphic Correlation

Nine dinosaur ichnospecies from the Lower Jurassic to Upper Cretaceous of Japan, including two that are new, are described herein. The new ichnotaxa are Asianopodus pulvinicalx ichnogen. et ichnosp. nov. and Schizograllator otariensis ichnosp. nov. The Japanese ichnotaxa are allied to Lower Jurassic ichnospecies in South China, North America, Western Europe and South Africa, and Upper Jurassic to Lower Cretaceous ichnospecies from Southeast and East Asia. This suggests they were part of a global ichnofauna before continental drift began in the Middle Jurassic, leading to the development of a more endemic dinosaur fauna in the Cretaceous. At least two assemblages, an ornithopod-gracile-toed theropod-dominated community, in northeastern Asia, and a robust theropod- and sauropod-dominated community in the southern part of the continent, existed in the Cretaceous. This parallels North American dinosaur distribution patterns in the Cretaceous and seems to be a reflection of paleolatitudinal controls.     

Late Cretaceous Mammal Tracks from North America

Mammal tracks from the latest Cretaceous (Campanian-Maastrichtian) of Colorado are described as Schadipes crypticus ichnogen. et ichnosp. nov., on the basis of material from the Laramie Formation in Golden, eastern Colorado. This ichnospecies, and a closely related form (Schadipes sp.) from the Mesaverde Group of western Colorado, represent the only mammal tracks so far identified from the Upper Cretaceous. A possible mammal track from North Africa (Agadirichnus elegans) was originally attributed to a lizard/lacertilian. Other purported Lower Cretaceous mammal tracks are based on isolated specimens of materials that are dubious or as yet undescribed in detail. Morphologically, Late Cretaceous mammal tracks resemble those of some modern rodents. However, based on the dominant mammalian elements of faunas at that time they are probably of marsupial or multituberculate affinity.     

Heinrichsia cheilanthoides gen. et sp. nov., a fossil fern in the family Pteridaceae (Polypodiales) from the Cretaceous amber forests of Myanmar

Divergence time estimates suggest that most clades constituting the fern family Pteridaceae (Polypodiales) were in existence by the Early Cretaceous. However, fossil evidence to corroborate this remains exceedingly rare. Burmese amber is an important source of new information on the radiation of derived fern lineages during the Cretaceous Terrestrial Revolution. This study describes Heinrichsia cheilanthoides gen. et sp. nov., a fern with suggested affinities to Pteridaceae, based on fertile foliage portions preserved in Early Cretaceous (~100 Ma) amber from Myanmar. Heinrichsia cheilanthoides is characterized by a pinnate‐pinnatifid frond that bears apical, marginal sori protected by a pseudoindusium. Sporangia are of the polypod type and contain tetrahedral‐globose, trilete spores with a striate perine. This discovery provides a new calibration point to test and refine molecular clock‐based concepts of the evolutionary history of the Pteridaceae. Heinrichsia cheilanthoides further substantiates the suggestion that the Cretaceous forests of Myanmar were home to a rich fern flora.     

Four new Psocoptera from Lebanese amber (Insecta: Psocomorpha: Trogiomorpha)

Four new trogiomorphan Psocoptera are described from the Lower Cretaceous Lebanese amber, viz. Bcharreglaris amunobi n. gen., n. sp., Setoglaris reemae n.gen., n. sp., Libanoglaris chehabi n.sp., and Libanoglaris randatae n. sp. These discoveries show that the Lower Cretaceous biodiversity of the Trogiomorpha was very high.     

A Cretaceous crane-fly (Diptera: Tipulidae): 93 million years of stasis

A new fossil species of crane-fly, Helius botswanensis:Diptera: Tipulidaey is described. The specimen was discovered recently in reliably dated. Cretaceous sediments from Botswana. Ii is extremely well preserved, has a distinctive morphology, and is identified as belonging to the extant genus Helius. The single specimen puts the origin of the subfamily Limoniinae and the genus well into the Cretaceous Period, and provides data on the southern African Cretaceous palaeoenvironment. The conservative nature of a dipteran of such antiquity, assignable to an extant genus which has an association with flowers, has implications for evolutionary theory.     

Changes in lifestyle and habitat of Zoophycos‐producing animals related to evolution of phytoplankton during the Late Mesozoic: geological evidence for the ‘benthic‐pelagic coupling model’

The trace fossil Zoophycos characterized by complex, three‐dimensional morphology with systematic internal structures occurs throughout the Phanerozoic marine sediments. The specimens of Zoophycos examined herein consist of a downward and helical spreite and are a product of the excretory behaviour of endobenthic detritus feeders. They are divided into two basic types: pre‐Jurassic and post‐Cretaceous types on the basis of whorls of spreiten in a single specimen. The pre‐Jurassic type has fewer than four whorls. In contrast, most of the post‐Cretaceous specimens exhibit spreite with multiple coils more than ten whorls. The abrupt increase in whorl number during the Cretaceous suggests that the sedentary lifestyle of the producer should change from a short‐term stay to long‐term or permanent occupation of the same burrow. Timing of the lifestyle change the Zoophycos producers seems to be closely related to the deep‐seaward migration of their habitats. The change in lifestyle and migration of Zoophycos‐producing animals during the Cretaceous might be attributable to the establishment of eutrophic bottom conditions in the deep sea. These changes seem to be associated with the flux of large amounts of phytodetrital food produced by phytoplankton, which experienced an explosive increase in species diversity during the Late Jurassic to the Late Cretaceous. The series of changes in lifestyle and habitat of the Zoophycos animals during the Late Mesozoic can serve as one piece of geological evidence for the ‘benthic‐pelagic coupling model’.     

A new plesiosaur of the family aristonectidae from the early cretaceous of the center of the Russian platform

A new plesiosaur, Abyssosaurus nataliae gen. et sp. nov. from the Upper Hauterivian Substage (Lower Cretaceous) of Chuvashia, is described based on a postcranial skeleton. The new taxon is assigned to the family Aristonectidae where it presumably occupies an intermediate position between Late Jurassic Tatenectes and Kimmerosaurus and Late Cretaceous Aristonectes and Kaiwhekea. This is the first reliable record of this family in Russia.     

Pinoid woods with resin canals from the upper cretaceous of Hokkaido and Saghalien

This paper describes six species of permineralized pinoid woods with resin canals from the Upper Cretaceous of Hokkaido, Japan and Saghalien:Piceoxylon transiens Shimakura,P. scleromedullosum Shimakura,P. macroporosum sp. nov.,P. takahashii sp. nov.,Pinuxylon microporosum Ogura andPinoxylon dakotense (Knowlton) Read (new to Saghalien and the Cretaceous).Piceoxylon macroporosum is characterized by large resin canals and rays without ray tracheids and in lacking tylosoids in resin canals.Piceoxylon takahashii, which resemblesP. scleromedullosum, is distinguished from the latter in having ray tracheids and nests of sclereids in pith. Structure and affinities of the petrified plants from the Cretaceous of Northern Japan and Saghalien XVI. (continued from Ohsawaet al. 1995)