INVESTIGATIONS OF ANGIOSPERMS FROM THE EOCENE OF NORTH AMERICA: RHAMNUS MARGINATUS (RHAMNACEAE) REEXAMINED

Leaf compressions, previously assigned to Rhamnus marginatus Lesquereux, were collected from the Middle Eocene Claiborne Formation of western Kentucky and Tennessee. The leaf architecture and cuticular features of over 40 compressions were carefully examined and compared to those of many extant species of Rhamnaceae and related families as well as fossil specimens previously assigned to this taxon. This leaf type appears to belong to the Rhamnaceae, however, it conforms more closely to species of several genera in the tribe Zizypheae than to those of Rhamnus or other genera in the tribe Rhamneae. Confident assignment to any specific genus within this complex of genera cannot be made on the basis of leaf characteristics alone and would require discovery and analysis of additional vegetative and reproductive organs. Because this fossil leaf form cannot be confidently assigned to any modern genus and earlier classifications appear to be improper, this leaf type has been reassigned to the taxon Berhamniphyllum claibornense gen. et sp. nov. The transfer of this leaf form at the tribe level reaffirms the need for close examination of taxonomic determinations made by early workers.     

TAXONOMIC CHARACTERISTICS OF SPHENOPHYLLALEAN CONES

The range of variability in the taxonomic characteristics traditionally used to establish genera and species of Sphenophyllum cones is studied from specimens of Bowmanites dawsoni, B. trisporangiatus, B. bifurcatus, Litostrobus, and Sphenostrobus. Taxonomic criteria examined include configuration of the cone stele, number of sporangiophores per bract, anatropous vs. orthotropous sporangium attachment, number of appendages per node, and spore morphology. Because of the large degree of variability observed, these characteristics do not appear to adequately differentiate between the genera Litostrobus and Sphenostrobus, so these genera are combined under Sphenostrobus. A new combination, S. iowensis, is proposed for specimens previously described as L. iowensis, L. paulus, and B. moorei. It is suggested that species currently placed in the genus Bowmanites may represent several distinct natural genera of sphenophyllalean cones.     

POROSTROBUS NATHORSTII SP. NOV.: A NEW SPECIES OF LYCOPSID CONE FROM THE EARLY PENNSYLVANIAN OF ILLINOIS

Thirty-one specimens of a small megasporangiate lycopsid cone referable to the genus Porostrobus Nathorst and abundant associated dispersed megaspores have been collected from Early Pennsylvanian strata in the Allied Stone Company quarry, Milan, Illinois. Based on other elements in the flora, the deposit is considered to be part of the Morrowan Caseyville Formation and probably of Namurian age. This is the first reported occurrence of Porostrobus in North America and the cones are recognized as a new species, P. nathorstii. The environment of deposition indicates that the cones may have been transported from the parent plant prior to preservation. Cones are preserved as coalified compressions measuring 15–36 mm long by 2.5–7 mm wide, and are characterized by an apical tuft of leaves up to 20 mm long. Sporophylls are spirally arranged on a narrow cone axis, lack a heel or keel, and have a long distal lamina. Sporangia contain a single functional megaspore tetrad. Mature megaspores are 750–1, 150 μm in diameter, have prominent trilete sutures raised to form a gula, and have numerous branched hairs confined to an equatorial band. Megaspores correspond to the dispersed form Setosisporites praetextus (Zerndt) Potonie and Kremp. Porostrobus nathorstii is the only species of the genus described to date that is monosporangiate.     

HORSETAILS AND SEED FERNS FROM THE MIDDLE TRIASSIC (ANISIAN) LOCALITY KÜHWIESENKOPF (MONTE PRÀ DELLA VACCA), DOLOMITES, NORTHERN ITALY

Abstract:  Well-preserved floras from the Alpine Early–Middle Triassic are rare, and thus our understanding of the vegetation in this area during this period of time continues to be incomplete. As a result, every new find represents a significant piece of information that deserves thoughtful consideration. Anisian (Middle Triassic) sphenophytes and pteridosperms have recently been recovered from the Kühwiesenkopf locality (Monte Prà della Vacca) in northern Italy. The sphenophytes are represented by stem fragments, strobili and isolated sporangiophore heads of Equisetites , as well as by a few specimens of Neocalamites sp. and Echinostachys sp. The pteridosperms include abundant remains of the peltasperm foliage type Scytophyllum bergeri . A second Scytophyllum species in this flora, S. apoldense , is regarded as conspecific with S. bergeri based on epidermal anatomy; the two morphotypes are interpreted as sun and shade leaves of a single biological species. The seed-bearing disc Peltaspermum bornemannii sp. nov. probably represents the female reproductive structure of S. bergeri . Additional pteridosperm remains include foliage assignable to Sagenopteris sp. and Ptilozamites sp., in both cases perhaps the earliest records of these genera.     

FOSSIL OPHIOGLOSSALES IN THE PALEOCENE OF WESTERN NORTH AMERICA

Vegetative and fertile frond segments of Botrychium have been recovered from Paleocene deposits of central Alberta, Canada. Specimens are preserved as coalified compressions that yield information about frond structure, sporangia, and spore ultrastructure. These fossils, described as Botrychium wightonii sp. nov., establish a megafossil record for the Ophioglossales, and demonstrate that modern-appearing species of the order were present in western North America by the earliest Tertiary. The largest vegetative fragments are up to 4.6 cm long and tripinnately compound, with opposite to subopposite branching. Ultimate segments are pinnatifid with dentate pinnules and open dichotomous venation. Fertile specimens are also tripinnately compound with a long rachis and subopposite to alternate pinnae. Sporangia are either submarginal and superficial, or marginal, and are all directed toward one surface of the pinnule. They are ovoid to subspheroidal and 0.8-2.0 mm in diameter. Some sporangia are apparently stalked, while others appear to be sessile. This variation results both from the ultimate frond segments being compressed in several different planes, and the fossils being exposed at different levels. Spores macerated from the sporangia are radial and trilete, and range 30–67 μm in diameter. Most are psilate, but some have a densely striate surface.     

CONE AND OVULE ONTOGENY IN TAXODIUM AND GLYPTOSTROBUS (TAXODIACEAE – CONIFERALES)

Seed cones in Taxodium distichum and Glyptostrobus pensilis occupy the position of permanent shoots and are initiated in the summer preceding spring pollination. Morphological features are similar in the two genera, reflecting their close taxonomic relationship. Ovule complexes originate as two (rarely more) ovule primordia in the axil of each fertile bract but without any indication of a preceding discrete ovuliferous scale. When the nucellus, integument, and micropyle are well developed, a series of up to ll abaxial lobes forms at the base of each ovule pair. They become fused by basal growth. After pollination the common basal meristem of lobes and bract extends by intercalary growth to form the conspicuous “ovuliferous scale” of the mature cone; the lobes enlarge and exceed the ovules. Despite the topographic similarity in the cones of both genera, there are differences in vasculature such that the vascular traces to the axillary complex originate directly from the axial cylinder in Glyptostrobus but from the bract trace in Taxodium. The complex vasculature of the mature cone develops late and primarily as an expression of intercalary growth.     

NEW TAXODIACEOUS SEED CONES FROM THE UPPER CRETACEOUS OF NEW JERSEY

Nephrostrobus cliffwoodensis gen. et sp. nov., Nephrostrobus bifurcatus sp. nov., and Rhombostrobus cliffwoodensis gen. et sp. nov. are described based on anatomical studies of seed cone fragments from the Upper Cretaceous Magothy Formation of New Jersey. These species belong to the Taxodiaceae. As in Sequoia, Sequoiadendron. and Metasequoia, the vascular strands supplying the scale and bract in Nephrostrobus are about equal. These vascular strands are arranged in a reniform pattern resembling that found in Metasequoia, but the orientation differs by 180 degress. Nephrostrobus cliffwoodensis and Nephrostrobus bifurcatus differ from each other in the branching of the complex trace and associated resin canals. Rhombostrobus cliffwoodensis resembles Cunninghamia in the arrangement of vascular strands and associated resin canals in its bract-scale complexes. However, the relative amount of bract and ovuliferous scale making up the complex is more like that in Sequoia. This combination of cone features does not occur in any of the extant genera. Nephrostrobus and Rhombostrobus are not considered to be ancestral to any of the extant taxodiaceous genera, but are extinct members of an ancestral complex from which the extant genera were derived.     

Structure and affinities of the petrified plants from the cretaceous of northern Japan and Saghalien XI A cupressoid seed cone from the Upper Cretaceous of Hokkaido

Archicupressus is a new genus of the Cupressaceae based on a permineralized conifer female cone from the Upper Cretaceous of Hokkaido. The type species,Archicupressus nihongii sp. nov., is characterized by peltate bract-scale complexes consisting of a completely fused bract and scale bearing erect seeds. Bract-scale complexes are arranged in whorls of three on the cone axis. Each complex has a bristle-like projection, the bract apex, at the top. Affinities to some genera in the Cupressaceae are discussed. Consecutive number from the previous paper (Ohsawaet al., 1992). Supported by a Grant-in-Aid for Scientific Research from the Ministry of Education, Science and Culture of Japan to Makoto Nishida, No. 02640533.     

Defining the gigantopterid concept: a reinvestigation of Gigantopteris (Megalopteris) nicotianaefolia Schenck and its taxonomic implications

Reinvestigation of the first described gigantopterid plant, Gigantopteris (Megalopteris) nicotianaefolia Schenk ex Potonié, 1902 from the Permian of China, has been conducted using the original specimens documented in 1883. The application of new techniques has permitted a comprehensive review of their morphology. This study represents the first photographic record of Schenk's specimens and provides a standardised terminology to describe them. This species of Palaeozoic leaf megaphyll is characterised by its pinnate venation, with tertiary veins that anastomose, and give rise to branches that may be of the same or higher order. These anastomosed branches form a reticulum of irregular polygonal meshes, within which higher order veins anastomose and again form meshes. On examination of Schenk's original specimens only one, MB.Pb.2002/989, can be assigned to Gigantopteris nicotianaefolia, and this is herein designated the lectotype. The remaining specimens described by Schenk are reassigned to cf. G. nicotianaefolia, cf. Gigantopteris sp., Gigantonoclea sp. or cf. Gigantonoclea sp. This re‐analysis of Schenk's specimens has led to an emended diagnosis of both the genus Gigantopteris and the species G. nicotianaefolia. Current evidence suggests that Gigantopteris nicotianaefolia is restricted to the southern floral regions of Cathaysia, as typically are other species of this genus. Fertile specimens of Gigantopteris are unknown, and the status of these plants as a natural group relies upon a combination of their complex foliar physiognomy, stratigraphic range, and geographical distribution. This study indicates that the genera GigantopterisGigantonoclea form the basis of the gigantopterid concept. These two genera share characters of leaf morphology including megaphylls with eucamptodromous venation across which extends a continuous lamina, and higher order veins, third order or above, that arise from the secondary veins and anastomose to form complex meshes. These genera are distinguished in that the venation of Gigantopteris is far more complex than that of Gigantonoclea, with a greater number and complexity of vein orders, the penultimate and ultimate of which form meshes within meshes, and of these the finest may terminate in blind endings.     

Pollination biology of Gnetum (Gnetaceae) in a LOWLAND MIXED DIPTEROCARP forest in Sarawak

Pollination biology of two Gnetum species was studied in a lowland mixed dipterocarp forest in Sarawak, Malaysia. A dioecious shrub species, G. gnemon var. tenerum, flowered in the evening and its strobili emitted a stinking odor. Pollination droplets were secreted from ovules on female strobili and from sterile ovules on male strobili in the evening. These strobili were visited by nectar-seeking moths of Pyralidae and Geometridae. Sticky pollen was attached on proboscides and antennae of these moths. A dioecious woody climber, G. cuspidatum, had cauline strobili on woody stems near the forest floor. Its male strobili emitted a funguslike odor in the evening and secreted nectar on collars that subtended “flower” rings. The strobili were visited by small flies of Lauxaniidae (Diptera), onto the antennae and legs of which pollen was attached. Evaporation of the exposed droplet/nectar of these Gnetum flowers seemed to be minimized by nocturnal flowering near the tropical rain forest floor. Another floral-structural constraint of gymnosperms, i.e., lack of showy petals, was compensated for by floral fragrancy. The prevalence of entomophily in the Gnetales (i.e., Gnetum, Ephedra, and Welwitschia) may suggest that unspecialized insect pollination originated before the divergence between the Gnetales and angiosperms.     

New records of two deep-sea eels collected from the Western Pacific Ocean based on COI and 16S rRNA genes

Background

Two deep-sea eels collected from the Western Pacific Ocean are described in this study. Based on their morphological characteristics, the two deep-sea eel specimens were assumed to belong to the cusk-eel family Ophidiidae and the cutthroat eel family Synaphobranchidae.

Methods and results

To accurately identify the species of the deep-sea eel specimens, we sequenced the mitochondrial genes (cytochrome c oxidase subunit I [COI] and 16S ribosomal RNA [16S rRNA]). Through molecular phylogenetic analysis based on mtDNA COI and 16S rRNA gene sequences, these species clustered with the genera Bassozetus and Synaphobranchus, suggesting that the deep-sea eel specimens collected are two species from the genera Bassozetus and Synaphobranchus in the Western Pacific Ocean, respectively.

Conclusions

This is the first study to report new records of the genera Bassozetus and Synaphobranchus from the Western Pacific Ocean based on COI and 16S rRNA genes

     

Inflorescence bracts of fossil and extant Tilia in North America,Europe, and Asia: patterns of morphologic divergence and biogeographic history

The enlarged inflorescence bract diagnostic of extant Tilia has an extensive Tertiary fossil record in the Northern Hemisphere. Diversity of bract morphology, and the extent of adnation between peduncle and bract, is reviewed for fossil and extant species of Tilia. An extinct type of bract with an orbicular outline and palmate venation is documented by the fossil species Tilia circularis (Chaney) comb. nov. from the early Oligocene of Oregon and is designated Type A. Living species of the genus have elongate bracts with predominately pinnate venation that are borne in two basic configurations: Type B, with the peduncle fused only to the extreme base of the bract lamina, as in extant Tilia endochrysea Hand.-Mzt. of southern China; and Type C with the peduncle fused medially along the basal one-third of the bract lamina, as in most extant species. Bracts of Type B were widely distributed in the Tertiary of western North America (late Eocene to Miocene) and Europe (early Miocene to Pliocene), while those of Type C are known in the fossil condition only from the middle and late Tertiary of Asia and Pliocene of Europe. The bracts of T. circularis, like those of type B, are borne on relatively long stalks and have the peduncle fused only at the extreme base. The fossil record supports recognition of the following characters as apomorphic in Tilia bract evolution: bracts sessile, peduncle adnate to the upper surface of the bract, and pinnate bract venation.     

A NEW SPECIES OF PICEA BASED ON SILICIFIED SEED CONES FROM THE OLIGOCENE OF WASHINGTON

Picea eichhornii n. sp. is described from anatomically preserved seed cones. The fossils are from the Early Oligocene Jansen Creek Member of the Makah Fm. which is exposed along the northern shore of the Olympic Peninsula, Washington. The cones are at least 5.5 cm long and up to 3.5 cm in diameter. The cone axis is 4–6 mm in diameter and contains a pith made up of thick-walled parenchyma cells. Resin canals occur in a single ring in the secondary xylem in some specimens but are absent in others. The cortex is mostly parenchymatous and contains numerous large axial resin canals that branch to supply the bract and scale. Vascular traces to each scale and its subtending bract diverge separately from the vascular cylinder of the cone axis. The bract is tongue-shaped and keeled at its base. It is 5 mm wide and up to 9 mm long. The bract trace fades out before entering the bract base while two resin canals extend into the bract base. The ovuliferous scale is about 2.3 cm long and has a thin, probably papery, apex. Resin canals of the scale occur abaxial to the vascular tissue in the scale base, but some bend around the margins of the vascular strand to become adaxial outward. About 20 resin canals occur in the abaxial scale sclerenchyma, and this is the main anatomical feature that distinguishes these cones as a new species. There are less than 14 such canals in cones in a reference collection of 15 modern species and in the two fossil species known from anatomically preserved material. While the new species adds to our knowledge of the diversity of Cenozoic Picea, its affinities within the genus remain undetermined.     

Male Cones in Taxaceae s. l. - an Example of Wettstein's Pseudanthium Concept

Abstract: Male cones of Taxus baccata L. and Torreya californica Torr. are mostly regarded as simple strobili ("flowers"). In the past some authors assumed that every single "sporangiophore" of Taxus baccata represents a whole "flower". The male cone of Taxus would then represent a compound strobilus ("inflorescence"). A cone of Cephalotaxus harringtonia (Knight ex J. Forbes) K. Koch and Cephalotaxus fortunei Hook. can easily be recognized as a compound strobilus composed of several simple strobili.
Our developmental studies by SEM give clues to the assumption that a simple male strobilus in Cephalotaxus is not homologous to the male strobili in Taxus and Torreya. Developmental, morphological and anatomical studies suggest that the simple strobili of Taxus and Torreya are derived from the compound strobili in Cephalotaxus by a transformation of the simple strobili into single sporangiophores. With respect to morphology, the male cones in Taxus and Torreya are simple strobili, but comparative developmental studies show that they are derived from compound strobili in a process similar to Wettstein's pseudanthium hypothesis. In the light of our studies, it is not unlikely that the male cones in Pinaceae also represent transformed compound strobili.     

INDIAN OCEAN NANOPLANKTON. I. RHABDOSPHAERACEAE (PRYMNESIOPHYCEAE) WITH A REVIEW OF EXTANT TAXA1

Family characteristics of the Rhabdosphaeraceae are revised to limit the genera to those having cyrtoliths; genera with placoliths are removed from the family. Rhabdoliths, cyrtoliths bearing a process in the central area, are present in all genera. Coccospheres having monomorphic coccoliths, all being rhabdoliths, form one group within the family, whereas genera with dimorphic coccoliths in the coccosphere comprise a second group. Cyrtoliths without processes in the latter group may be intermixed with rhabdoliths in some genera, whereas other genera have rhabdoliths located only in polar regions of the coccosphere. Two generic nomenclatural changes are proposed, Algirosphaera being the name applied to species previously placed in Anthosphaera, an invalid generic name, and Palusphaera is recognized as a valid monotypic genus, P. vandeli being the name applied to the species that has been named Rhabdosphaera longistylis in recent literature. A new combination is made, Rhabdosphaera xiphos (Deflandre et Fert) comb. nov., recognizing a species formerly known only in sediments as extant. Rhabdosphaera, Acanthoica and Algirosphaera are genera with dimorphic coccoliths in the coccospheres; Discosphaera, Palusphaera and Anacanthoica are genera having monomorphic coccoliths in the coccosphere.     

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).     

Mospicalanus schielae,a new genus and species of calanoid copepod (Crustacea: Spinocalanidae) from deep Antarctic water

A new genus and species,Mospicalanus schielae, collected at bathypelagic depth in the Antarctic Ocean, is described from female specimens and a stage V male. The new species is placed in the Spinecalanidae on account of the absence of fifth legs and leg 1 characteristics. It appears to be closely related toMimocalanus Farran. 1908, sharing apomorphic characters such as the lack of a rostrum, reductions of setal armament on the mouthparts, and absence of an outer spine on the first exopod segment of leg 1.Mospicalanus schielae can be distinguished from other spinocalanid genera by the setation of the antennary exopod, the maxillule, and the paecoxal endite of maxilla. Diagnostic characters of Spinocalanidae and Bathypontiidae are also discussed in order to clarify affiliation of genera tentatively assigned to the latter family. An updated key is given for the spinocalanid genera.     

Keraunea gen. nov. (Convolvulaceae) from Brazil

Keraunea Cheek & Simão‐Bianchini gen. nov. (Convolvulaceae) from Brazil is described and illustrated as the third known neuropeltoid genus. It appears allied to the Old World genera of Neuropeltis Wall and Neuropeltopsis Ooststr. in having wind‐dispersed fruits not by enlarged sepals, but subtended by an enlarged papery bract to which the pedicel is adnate, and flowers in which the bracteoles are absent or usually very inconspicuous. Keraunea brasiliensis, the single species thus far known, is here assessed as ‘Endangered’.     

POLLINATION DROP IN RELATION TO CONE MORPHOLOGY IN PODOCARPACEAE: A NOVEL REPRODUCTIVE MECHANISM

Observation of ovulate cones at the time of pollination in the southern coniferous family Podocarpaceae demonstrates a distinctive method of pollen capture, involving an extended pollination drop. Ovules in all genera of the family are orthotropous and single within the axil of each fertile bract. In Microstrobus and Phyllocladus ovules are erect (i.e., the micropyle directed away from the cone axis) and are not associated with an ovule-supporting structure (epimatium). Pollen in these two genera must land directly on the pollination drop in the way usual for gymnosperms, as observed in Phyllocladus. In all other genera, the ovule is inverted (i.e., the micropyle is directed toward the cone axis) and supported by a specialized ovule-supporting structure (epimatium). In Saxegothaea there is no pollination drop and gametes are delivered to the ovule by pollen tube growth. Pollination drops were observed in seven of the remaining genera. In these genera the drop extends over the adjacent bract surface or cone axis and can retain pollen that has arrived prior to drop secretion (“pollen scavenging”). The pollen floats upward into the micropylar cavity. The configuration of the cone in other genera in which a pollination drop has not yet been observed directly suggests that pollen scavenging is general within the family and may increase pollination efficiency by extending pollination in space and time. Increased pollination efficiency may relate to the reduction of ovule number in each cone, often to one in many genera, a derived condition. A biological perspective suggests that animal dispersal of large seeds may be the ultimate adaptive driving force that has generated the need for greater pollination efficiency.