Structure and affinities of the petrified plants from the cretaceous of Northern Japan and Saghalien XIIIYubaristrobus gen. nov., A new Taxodiaceous cone from the upper cretaceous of Hokkaido

Yubaristrobus is a new genus of the Taxodiaceae based on a permineralized seed cone from the Upper Cretaceous of Hokkaido. The type species,Y. nakajimae sp. nov., is characterized by peltate bract-scale complexes consisting of a completely-fused bract and scale. The bract-scale complexes are spirally arranged as in most taxodiaceous genera. Their vascular arrangement is specialized and unique in the Taxodiaceae and suggests a relationship with the Cupressaceae. Consecutive number from the previous paper (Ohsawa, M. Nishida and H. Nishida, 1992b).     

Structure and affinities of the petrified plants from the cretaceous of Northern Japan and Saghalien. XII.Obirastrobus gen. nov., petrified pinaceous cones from the Upper Cretaceous of Hokkaido

Two new species of pinaceous cones belonging toObirastrobus gen. nov. are described from the Upper Cretaceous of Hokkaido. Bract-scale complexes are arranged helically and each consists of a small bract and a large scale. The bract and scale are separated. The scale tapers distally and its apex does not become papery. The anatomy of the bracts, scales, and seeds shows a combination of features unique in the Pinaceae and resembling those of the extant genusKeteleeria and the extinct genusPseudoaraucaria. Consecutive number from the previous paper (Ohsawaet al., 1992). Supported by Grant-in-Aid for Scientific Research from the Ministry of Education, Science and Culture Nos. 63540545 and 02640533 to Makoto Nishida.     

Structure and affinities of the petrified plants from the cretaceous of Northern Japan and Saghalien III petrified plants from the upper cretaceous of Saghalien

Five species including two new species,Araucarioxylon kiiense Ogura,Taxodioxylon albertense (Penhal.) Shimakura,Cupressinoxylon cryptomerioides Stopes,Xenoxylon watarianum sp. nov. andCedroxylon shimakurae sp. nov., were described from the Upper Cretaceous (Late Turonian-Santonian) of southern Saghalien. Consecutive number from the previous paper (Nishida and Nishida, 1985). Contributions from the Laboratory of Phylogenetic Botany, Chiba University No. 100. Supported by a Grant-in-Aid for Scientific Research from the Ministry of Education, Science and Culture No. 59540441.     

Structure and affinities of the petrified plants from the cretaceous of Northern Japan and Saghalien IV petrified plants from the upper cretaceous of Saghalien (2)

Four species including two new species,Araucarioxylon pseudochoshiense sp. nov.,Taxodioxylon pseudoablertense Nishida et H. Nishida,Taxodioxylon nihongii Nishida et H. Nishida andTaxaceoxylon saghalienense sp. nov., were described from the Upper Cretaceous (Late Turonian-Santonian) of southern Saghalien. Consecutive number from the previous paper (Nishida and Nishida, 1986). Contributions from the Laboratory of Phylogenetic Botany, Chiba University No. 102. Supported by a Grant-in-Aid for Scientific Research from the Ministry of Education, Science and Culture No. 59540441.     

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)     

Pinus MUTOI (Pinaceae), a new species of permineralized seed cone from the upper Cretaceous of Hokkaido,Japan

Pinus mutoi is described as a new species on the basis of a permineralized seed cone from the Upper Cretaceous of Hokkaido, Japan. The cone is at least 20 cm long and up to 6 cm in diameter, consisting of a cone axis and numerous cone-scale complexes that are arranged helically around the axis. Two winged seeds are borne on the adaxial surface of each ovuliferous scale. Each complex receives a single trace from the vascular cylinder of the cone axis. In the scale base, all the resin canals occur abaxially to the vascular strand. The spatulate bract of the fossil is unique to the specimen among the cones of both living and fossil Pinus. The central umbo, broad sclerotic cortex of cone axis, and absence of serotinous features of the fossil cone suggest affinity with the subsection Sylvestres of the section Pinus, subgenus Pinus. This is the first record of permineralized preserved Pinus cone from the Cretaceous of Eastern Eurasia.     

Anatomy and relationships of petrified seed cones of the Cupressaceae,Taxodiaceae, and Sciadopityaceae

Morphological features and the affinities of petrified seed cones of the Taxodiaceae, Cupressaceae, and Sciadopityaceae are reevaluated. TheCunninghamia-like plants are the earliest record of the families.Parataiwania explains the divergence ofTaiwania from aCunninghamia-like ancestral form by loss of ovuliferous scale and sclerenchyma.Sequoia-like allies probably diverged from a Cretaceous transitional plant likeYezosequoia and are most diversified in the Late Cretaceous.Yubaristrobus andArchicupressus suggest monophyly ofTaxodium and its allied genera of the Taxodiaceae and the Cupressaceae. The Cupressaceae may be derived from a taxodiaceous plant with orthotropous seeds, acquiring a reniform arrangement of the vascular bundles of the bract-scale complex, decussate or whorled phyllotaxis, and spherical cones consisting of a small number of bract-scale complexes. The Cretaceous fossils of the Sciadopityaceae suggest the ancient origin of the family.     

Anatomy and affinities of the petrified plants from the tertiary of chile V

Four species of dicotyledonous woods including three new species,Aextoxicoxylon harambouri sp. nov.,Myrceugenellites maytenoides sp. nov.,Laurelites doroteaensis sp. nov. andLaurinoxylon uniseriatum Gothan, were described from the Tertiary of Cerro Dorotea, Ultima Esperanza and Fuego Island, Chile. It was elucidated thatNothofagoxylon boureaui Salard from Cerro Dorotea is synonymous withLaurinoxylon uniseriatum from Antarctica. Consecutive number from the previous paper (Nishida, 1984). Contributions from the Laboratory of Phylogenetic Botany, Chiba University No. 118 and contributions from Chiba University Botanical Expedition to the Andes No. 17. Supported by a Grant in-Aid for Overseas Scientific Survey from the Ministry of Education, Science and Culture Nos. 7405, 404114 and 62043014.     

Use of fluorescent microscopy in defining a small ligule-like ovuliferous scale of a permineralized taxodiaceous cone from the upper cretaceous of Hokkaido,Japan

Fluorescent microscopy was proved to be effective for structural identification of permineralized plant tissues in calcite nodules from the Upper Cretaceous of Hokkaido, Japan. A minute, scale-like projection on the bract of a fossil Taxodiaceous cone is identified as a true ovuliferous scale because it is bordered with a continuous epidermis that exhibits prominent fluorescence. The presence of the ovuliferous scale suggests that the fossil is aTaiwania archetype.     

Anatomy and affinities of the petrified plants from the teriary of Chile (VI)

Three new species and one new genus of dicotyledonous woods,Chilechicoxylon microporosum gen. et sp. nov.,Proteoxylon patagonicum sp. nov. andLaurinium beilschmiedioides sp. nov., are described from the Tertiary (or in case of the first and last species from the Cretaceous-Tertiary) of Chile Chico, XI Region, Chile. Previously only wood of temperate species has been identified from Patagonia.Proteoxylon patagonicum (Proteaceae) is the first recorded tropical wood species from this geographical area. Consecutive number from the previous paper (M. Nishida, H. Nishida and T. Nasa, 1988). Contributions from the Laboratory of Phylogenetic Botany, Chiba University No. 120 and contributions from Chiba University Botanical Expedition to the Andes No. 20. Supported by a Grant-in-Aid for Overseas Scientific Research from the Ministry of Education, Science and Culture Nos. 61041015 and 63041034.     

Structure and affinities of the petrified plants from the Cretaceous of Japan and Saghalien,V. Tree fern stems from Hokkaido,Paracyathocaulis ogurae gen. et comb. nov. andCyathocaulis yezopteroides sp. nov.

Paracyathocaulis ogurae gen. et comb. nov. andCyathocaulis yezopteroides sp. nov. are Late Cretaceous tree-fern stems with cyatheaceous affinity. They are comparable with the Recent scaly cyatheoids (Cyathea s.l.), as well as with the Cretaceous and Tertiary fossil stems that have similar anatomy. All of these tree ferns, including the Late Jurassic to Early CretaceousOguracaulis Tidwellet al., comprise a well-defined morphological complex within Cyatheaceae, and are considered to be monophyletic. The taxonomy of this complex is analyzed cladistically, and the cladogram is phylogenetically evaluated by reference to the chronological data of fossils.     

Diversity and significance of late cretaceous permineralized plant remains from Hokkaido,Japan

Middle to Late Cretaceous permineralized plants hitherto described from Hokkaido, Japan are summarized. The fossil flora comprises fungi, ferns, gymnosperms and angiosperms. Many modern fern families have been recognized including Anemiaceae, Cyatheaceae, Dennstaedtiaceae, Gleicheniaceae Loxsomaceae, Lygodiaceae and Matoniaceae. Gymnosperms are most abundant in the flora. Some recently-found materials are tentatively introduced with brief comments emphasizing their morphological and taxonomical significance. A bisporangiate flower ofCycadeoidella japonica Ogura shows fine internal anatomy and provides evidence that the cycadeoidalean ovule was a cupulate, unitegmic structure. Vascular tracheids in the synangial wall support the evolution of cycadeoidalean synangia from Paleozoic seed-fern synangia. A new gymnosperm female fructification has a thick envelope comparable to an angiosperm carpel around a large seed. The angiosperms contain various morphologies that require further extensive study.     

Yezonia,a new section ofAraucaria (Araucariaceae) based on permineralized vegetative and reproductive organs ofA. vulgaris comb. nov. from the upper cretaceous of Hokkaido,Japan

A new specimen of an araucarian cone,Araucaria nihongii, was found attached to the vegetative organs ofYezonia vulgaris, and is described asAraucaria vulgaris comb. nov. Thick branches show characteristic bark structure with lenticular patches. Secondary wood is usually araucarioid. Leaves are arranged helically on shoots, which are imbricate, appressed and fused to surface of the stem. External and anatomical features of leaves closely resembleBrachyphyllum. The seed cone is spherical with winged bracts and thin ovuliferous scales. One seed is borne per cone-scale complex. The seed coat and nucellus wall show typical araucarian structure. An araucarian plant that boreBrachyphyllum-like foliage and aEutacta-like seed cone was predicted by Harris in 1979. This reconstructed plant,Araucaria vulgaris, supports this theory and proves the presence of an extinct characteristic-form of the genus. A new section of the genus was proposed forAraucaria vulgaris. Structure and Affinities of the Petrified Plants from the Cretaceous of Northern Japan and Saghalien XV, Consecutive number from previous paper (Nishidaet al. 1993).     

Upper Cretaceous aquatic plants from Northern Mexico

Two aquatic plant genera assignable to Decodon (Lythraceae) and Ceratophyllum (Ceratophyllaceae) are described based on reproductive structures collected from the Cerro del Pueblo Formation (late Campanian [73.5 ma]), Coahuila, Northeast Mexico. Decodon is represented by three small seeds with a pyramidal shape, rounded borders, and a concave ventral surface with a rectangular valve towards the center of the seed ventral surface. The Ceratophyllum spiny fruit has an ellipsoidal central body and two proximal long spines flanking a short pedicel opposite the stylar projection. These new reports confirm the presence of both genera in the Upper Cretaceous sediments of Northeastern Mexico, and add to our recognition of diversity within the widely distributed freshwater communities along the margin of the epicontinental sea.     

Archamamelis,hamamelidalean flowers from the Upper Cretaceous of Sweden

Lignite fossil flowers (including pollen) and isolated stamens of probable hamamelidalean (possible hamamelidaceous) affinities from the upper Cretaceous (Late Santonian or Early Campanian) of Sweden are described. The flowers are 6–7-merous with probably a double perianth, one whorl of stamens and (2-?)3 carpels. The stamens are disporangiate; each theca opens by a valve towards the centre of the flower. Pollen is tricolpate, tectate-columellate and reticulate; the endexine is lamellated in the apertural region. The gynoecium has free styles and a syncarpous ovary. In the one flower that was serially sectioned the ovary is either non-functional or development of the few (2?) ovules is retarded.     

Ephedroid fossil pollen from the Lower Cretaceous (Upper Albian) of Hokkaido,Japan

This paper presents eight ephedroid palynomorphs from the Lower Cretaceous (Upper Albian) of Hokkaido, Japan. The ephedroid palynomorphs are ellipsoid and polyplicate pollen grains that show a wide range of variation in pollen size, shape, and plication. These ephedroid palynomorphs suggest a wide range of diversity in Gnetales at mid- or high-paleolatitude in the eastern side of Lauresia during the Upper Albian.     

Fossil flowers and pollen ofLauraceae from the Upper Cretaceous of New Jersey

A fossil trimerous flower from the Turonian (ca. 90 MYBP, Upper Cretaceous) of New Jersey is described as a new genus in the familyLauraceae. The fossil flower is charcoalified and preserved in exceptional detail. This fossil specimen is particularly remarkable in that several pollen grains have been preserved; pollen grains ofLauraceae generally have very thin exine and are rarely preserved in the fossil record. Although the specimen is incomplete and lacks anthers, there are sufficient structural details preserved to permit an assignment to theLauraceae, as well as comparisons with the tribePerseeae. This new genus provides an important addition to our knowledge of systematic and structural diversity in CretaceousLauraceae.     

A new Bennettitalean trunk with unilacunar five-trace nodal structure from the Upper Cretaceous of Hokkaido, Japan

A new species of Bucklandia is described based on a permineralized fossil trunk that was obtained from sediments of Upper Cretaceous age from Hokkaido, Japan. The quality of preservation is exquisite, and anatomical and morphological features are preserved at the cellular level. The specimen is clearly bennettitalean because of the cycadeoidean-type arrangement of vascular bundles in the petiole. However, this specimen is unique among previously described progymnosperms and gymnosperms in possessing a unilacunar five-trace type of nodal structure. The fossil thus contributes to a more complete understanding of the variation of nodal structure in bennettitalean trunks.     

Phaeodarian Radiolaria from the Upper Cretaceous beds of central Japan

Upper Cretaceous Phaeodarea (Radiolaria) were recovered from the Shoya Formation, which crops out 100 km northwest of Tokyo, central Japan. The Shoya Formation consists of about 600 m-thick marine sedimentary rocks, represented by alternating beds of sandstone and mudstone, which are overlain by about 10 m of Phaeodarian-bearing siliceous mudstone. The latter is assigned to the Upper Cretaceous (late Campanian to early Maastrichtian) based on the associated Polycystine Radiolarian fossils. In spite of the poor general preservation of nearly all Phaeodarian specimens as recrystallized quartz infillings, three new Phaeodarian species, Challengeranium cretaceum, Challengeron paleotriangulum, and Medusetta fossilis, were identified on the basis of their shape and ornamentation. Our finding, together with two other very recent reports of fossil Phaeodarians clearly document that the origin of Phaeodarian Radiolarians can be extended back to at least the Upper Cretaceous.