MORPHOLOGY AND ANATOMY OF NEW SPECIES OF SCHIZAEA AND ACTINOSTACHYS

The gametophyte, old embryo, and sporophyte of Schizaea pseudodichotoma sp. nov., sporophyte and female parental gametophyte of S. diversispora hybr. nov. (S. pseudodicholoma X probably S. dichotoma), sporophyte of S. rhacoindusiata sp. nov., and gametophyte, old embryo, and sporophyte of Actinostachys macrofunda sp. nov. are described. The taxonomy of Schizaea is discussed and the system of Diels is strongly supported. The two sectional names used by Diels, Euschizaea Hook, and Lophidium Rich, are replaced by Pectinatae Prantl and Schizaea respectively. The prime morphological significance of Schizaea pseudodicholoma lies in its leafless embryo and its simple leaf differing from other species in its section, and that of Actinostachys macrofunda lies in its reduction to nearly complete heterotrophic existence and its frequent multiple annulus. Fungal hyphae have been traced from Schizaea and Actinostachys through the substratum and into root nodules of Casuarina and into roots of two other angiosperms.     

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.     

Documents pour servir à la reconstitution de la fronde chez certaines Neuroptéridées

Some datas recently collected are presented to show that the frond in the genus Neuropteris, built on a pseudopennate sympodial dichotomous type, eventually bears, at least in some species, a certain number of lateral portions below the general ending as an apical bifurcation.     

Fertile and sterile frond segments of the lyginopterid seed fern Feraxotheca

Fertile and sterile frond segments of the lyginopterid seed fern Feraxotheca culcitaus are described. In both the fertile and sterile specimen three orders of frond axes are borne alternately and in the same plane. Antepenultimate and penultimate frond axes are characterized by a C-shaped vascular bundle and numerous canals containing a golden-colored material in the fossilized condition. Synangia with only four sporangia demonstrate radial symmetry; bilateral symmetry is present in larger synangia. Pinnules possess dichotomous venation, with a single vein entering each lobe of the deeply incised lamina. A single canal occurs below each vein, and vein ends have an amplified vascular bundle. Morphologically Feraxotheca compares most closely with the compression genus Crossotheca. The morphology of the vascular bundle in the largest pinna is similar to a Lower Carboniferous specimen of Rhodea.     

Natural taxonomic categories of angiosperms obey Benford's law,but artificial ones do not

Benford's phenomenological law gives the expected frequencies of the first significant digit (i.e., the leftmost non-zero digit) of any given series of numbers. According to this law, the frequency of 1 is higher than that of 2; this in turn appears more often than 3, and so on decreasing until 9. Similarly, Benford's law can also be applied to the first two significant digits (i.e., from 10 to 99), and so on. We applied Benford's law to sets of taxonomic data sets consisting of the number of taxa included in taxa of higher rank. We chose the angiosperms (Magnoliophyta) as a model case, because they are very diverse, are monophyletic, and a consensus on taxonomy of orders and families has been achieved (classification APG III), and we used as sets of data the number of species, genera, families, and orders. Only the number of species per family and per order are Benford's sets, but the remaining data sets do not obey Benford. Furthermore, in the case of the analysis of the first two significant digits of species per genus, the deviation from Benford was very large, but they fit to a power law. Given that the conformity to Benford's law is fulfilled for ‘natural' taxonomic categories of angiosperms (i.e., species and family), but not for those with more artificiality (genus), we speculate, ‘the more natural, the more Benford'.     

Ectopic dermal ridge configurations on the interdigital webbings and postaxial marginal portion of the hindlimb in Hammertoe mutant mice (Hm)

The effects of the hereditary malformation of Hammertoe mutant mice (gene symbol Hm) on the digital pads and dermal ridge configurations on their hindlimbs were examined. In the wild‐type (+/+) mice with normally separated digits, dermal ridges developed only on the pads. Heterozygous (Hm/+) and homozygous (Hm/Hm) mutant mice, however, had a broad big toe, fused interdigital soft tissues, reduced claws, an extra rudimentary postaxial digit and camptodactyly. The dermal ridges appeared not only on the pads, affected in their number and configurations, but also on the ventral surface of the interdigital webbings and postaxial marginal area exhibiting an extra rudimentary digit and webbing. These aberrant configurations may be related to the abnormal occurrence of programmed cell death (PCD) in the interdigital zones and the postaxial marginal portion in Hm/+ and Hm/Hm mice. That is, the diminished cell death may fail to decrease the cell density in the interdigital zones and postaxial marginal portion and result in the webbing and an extra rudimentary digit and webbing, respectively. Simultaneously, it could also interrupt the migration of surviving cells of these areas toward the neighboring digits and the distal area of the sole and produce the ectopic dermal ridges on the way to the as yet unformed (presumptive) digital and plantar volar pads. The present findings suggest that normal interdigital and pre/postaxial PCD contributes not only to the separation of digits, the initial formation of individual digits of different sizes, and the inhibition of the extra digit but also to the development of the presumptive digital and plantar pads, including dermal ridges. J. Morphol., 2008. © 2008 Wiley‐Liss, Inc.     

Aspects of the ecology of a filamentous alga in a eutrophicated lake

In the eutrophic Lake Mikølajskie macrophytes disappearing from the deeper parts of the littoral are replaced by Vaucheria dichotoma Ag. This forms a belt at 3.0–4.5 m to which depth only 1% of surface light penetrates. The zone of V. dichotoma has a layered structure. Some filaments are covered in mud and receive no light, but are alive and photosynthesize when transferred to light. V. dichotoma prefers fertile environments with a high content of phosphate-phosphorus and ammonium-nitrogen. It is evergreen and its biomass changes relatively little during a year.     

The developmental evolution of avian digit homology: An update

The identity of avian digits has been unresolved since the beginning of evolutionary morphology in the mid-19th century, i.e. as soon as questions of phylogenetic homology have been raised. The main source of concern is the persistent discrepancy between anatomical/paleontological and embryological evidence over the identity of avian digits. In this paper, recent evidence pertaining to the question of avian digit homology is reviewed and the various ideas of how to resolve the disagreement among developmental and phylogenetic evidence are evaluated. Paleontological evidence unequivocally supports the hypothesis that the fully formed digits of maniraptoran theropods are digits DI, DII, and DIII, because the phylogenetic position of Herrerasaurus is resolved, even when hand characters are excluded from the analysis. Regarding the developmental origin of the three digits of the avian hand the discovery of an anterior digit condensation in the limb bud of chickens and ostriches conclusively shows that these three digits are developing from condensations CII, CIII, and CIV. The existence of this additional anterior condensation has been confirmed in four different labs, using four different methods: Alcian blue staining, PNA affinity histochemistry, micro-capillary regression and Sox9 expression. Finally, recent evidence shows that the digit developing from condensation CII has a Hox gene expression pattern that is found in digit DI of mice forelimb and chick hind limbs. The sum of these data supports the idea that digit identity has shifted relative to the location of condensations, known as Frame Shift Hypothesis, such that condensation CII develops into digit DI and condensation CIII develops into digit DII, etc. A review of the literature on the digit identity of the Italian Three-toed Skink or Luscengola (Chalcides chalcides), shows that digit identity frame shifts may not be limited to the bird hand but may be characteristic of “adaptive” digit reduction in amniotes (sensu Steiner, H., Anders, G., 1946. Zur Frage der Entstehung von Rudimenten. Die Reduktion der Gliedmassen von Chalcides tridactylus Laur. Rev. Suisse Zool. 53, 537–546) in general. In this mode of evolution two digits are lost, in the course of the adaptation of the three anterior digits to a function that does not require the two posterior digits. This evidence suggests that the evolution of digits in tetrapods can proceed at least on two distinct levels of integration, the level of digit condensations and that of adult digits.     

不同生境银柴胡根内生菌群落特征及其与药材主要有效成分、产量的相关性分析

【背景】银柴胡（Stellaria dichotoma var.lanceolata）具有重要的临床药用价值,其总甾醇和总黄酮含量是评价药材的关键。【目的】探究药用植物银柴胡在不同生境下根内生菌群落特征及其与药材主要成分、产量之间的关系。【方法】采用高通量测序技术和药材常规测定方法,分析了风沙土（semi-fixed aeolian sandy soil,SFA）生境、石砾质土（lithosol,LI）生境和黄绵土（loessal,LO）生境银柴胡根内生菌群落特征及其与药材性状响应关系。【结果】各生境银柴胡内生优势细菌门为放线菌门（Actinobacteriota）和变形菌门（Proteobacteria）,优势真菌门为子囊菌门（Ascomycota）和担子菌门（Basidiomycota）,而内生优势菌属因生境不同各不相同;银柴胡药材主要有效成分总甾醇和总黄酮含量在LI生境中较高,而单株干重和干鲜比在SFA生境中较高。Spearman相关性分析表明,与银柴胡药材有效成分及产量显著正相关的内生菌相对较多。综合比较,内生细菌如metagenome_g__norank_f__67-14和内生真菌如unclassified_p__Ascomycota等更为显著。【结论】与银柴胡药材关键活性成分相关的内生菌群落在种类鉴定和提取、菌种培养和次生代谢物分析等方面具有广阔的研究价值。本研究为银柴胡道地产区药材高质量产业发展提供理论参考。     

Are there general laws for digit evolution in squamates? The loss and re‐evolution of digits in a clade of fossorial lizards (Brachymeles,Scincinae)

Evolutionary simplification of autopodial structures is a major theme in studies of body‐form evolution. Previous studies on amniotes have supported Morse's law, that is, that the first digit reduced is Digit I, followed by Digit V. Furthermore, the question of reversibility for evolutionary digit loss and its implications for “Dollo's law” remains controversial. Here, we provide an analysis of limb and digit evolution for the skink genus Brachymeles. Employing phylogenetic, morphological, osteological, and myological data, we (a) test the hypothesis that digits have re‐evolved, (b) describe patterns of morphological evolution, and (c) investigate whether patterns of digit loss are generalizable across taxa. We found strong statistical support for digit, but not limb re‐evolution. The feet of pentadactyl species of Brachymeles are very similar to those of outgroup species, while the hands of these lineages are modified (2‐3‐3‐3‐2) and a have a reduced set of intrinsic hand muscles. Digit number variation suggests a more labile Digit V than Digit I, contrary to Morse's law. The observed pattern of digit variation is different from that of other scincid lizards (Lerista, Hemiergis, Carlia). Our results present the first evidence of clade‐specific modes of digit reduction.     

DATA AND DATA INTERPRETATION IN THE STUDY OF LIMB EVOLUTION: A REPLY TO GALIS ET AL. ON THE REEVOLUTION OF DIGITS IN THE LIZARD GENUS BACHIA

Galis and collaborators (2010) claim that our recent paper ( Kohlsdorf and Wagner 2006 ), presenting statistical evidence for the reevolution of digits in the genus Bachia, may be flawed. Their reanalysis of the data does not support the possibility of a reevolution of digits and the authors also argue that such a reevolution would be implausible on functional and developmental grounds. In response, we reanalyzed our data with additional outgroup species. Our results differ from the one published in 2006, but this incongruence is not statistically significant. In contrast, the hypothesis presented by Galis et al. is significantly worse. An analysis of digit number evolution, using novel techniques to test for irreversibility of character loss ( Goldberg and Igic 2008 ), confirmed our original conclusion that there is strong evidence for reevolution of digits in Bachia. We also point out that this result is not in conflict with the hypothesis by Galis and Metz (2001) that mutations affecting the initial digit patterning are associated with strong negative pleiotropic effects and thus unlikely to be fixed in evolution. An important avenue of future research will be to directly test whether reevolved digits develop from conserved digit condensations retained after digit loss.     

Developmental basis of mammalian digit reduction: a case study in pigs

Digit reduction has occurred in parallel in many mammalian lineages. However, despite this pattern's prevalence, the developmental mechanisms underlying mammalian digit reduction remain controversial. We therefore undertook a study of digit development in the pig (Sus scrofa), a mammal with reduced first, second, and fifth digits. Our results indicate that from its earliest formation, the pig limb bud is significantly narrower than that of the model pentadactyl mammal, mouse. Furthermore, the cartilage condensations of the pig's reduced digits are noticeably smaller than those of their nonreduced counterparts from the time of their formation. In addition, growth rates of pig digits are comparable, as are the patterns of cell death in developing pig and mouse limbs. Taken together, results suggest that pig's first, second, and fifth digits are primarily reduced through evolutionary modifications in the early developmental patterning of their limbs. Results of this study, coupled with those from study of limb development in other mammals, suggest that although major developmental reorganizations (e.g., complete digit or limb loss) during early limb development may be selected against, it may be common for more subtle evolutionary modifications in limb development (e.g., changes in relative digit size) to occur at this time.     

Osmunda (Osmundaceae) from the Triassic of Antarctica: an example of evolutionary stasis

Compressed specimens of the fern Osmunda are described from the Triassic of the Allan Hills, Antarctica. The specimens consist of a once pinnate, deeply pinnatifid fertile frond as well as several sterile specimens. Six pinnae are present on the partial fertile rachis, with two sterile pinnae above four fertile pinnae. Both sterile and fertile specimens are virtually identical to the modern species Osmunda claytoniana. Entire fronds are fragmentary; the longest is 21 cm in length. Sterile pinnae are alternate and deeply pinnatifid, with slightly toothed pinnules and dichotomous venation. Fertile pinnae are 1-1.3 cm long, once pinnate, and lack vegetative lamina. Sporangia are clustered, each 300-375 um in diameter, and possess a transverse annulus 6-8 cells long; dehiscence is by a vertical slit. Fronds arise from a rhizome 4 cm long by 1 cm wide; two croziers are present on the rhizome. Two frond segments up to 6 cm long and three deeply pinnatifid pinnae are present on the uppermost part of one rachis. Pinnules are ~4 mm long and 2-3 mm wide. The presence of this Osmunda species in the Triassic demonstrates stasis of frond morphology, both fertile and vegetative, for the genus.     

A taxonomic appraisal on the rare green algal genus Ecballocystopsis M.O.P.Iyengar (Chlorellales: Trebouxiophyceae): morphological and numerical approach

Ecballocystopsis (Oocystaceae, Chlorellales, Trebouxiophyceae) is a rare green algal genus, represented by only five taxa: E. dichotoma var. dichotoma from China and E. indica, E. desikacharyi, E. himalayensis and E. dichotoma var. minuta from India. Here we propose the novel variety E. dichotoma var. anandii from Jharkhand, synonymization of E. himalayensis with E. dichotoma and erection of E. dichotoma var. minuta to a separate species as E. minuta stat. et comb. nov. These taxonomic changes are well supported by the results of a multivariate analysis based on a numerical taxonomic approach. Cluster analysis (CA), principal component analysis (PCA) and principal coordinates analysis (PCoA) were performed to resolve the species delimitation ambiguity and supplement the morphology-based classification of the genus. Ecballocystopsis himalayensis and E. dichotoma grouped in a single cluster along with the proposed new variety, while E. indica, E. desikacharyi and E. minuta formed separate clusters. An identification key to the species of the genus Ecballocystopsis is also presented.     

THE MORPHOLOGY AND RELATIONSHIPS OF RHODEA,TELANGIUM, TELANGIOPSIS,AND HETERANGIUM

This study deals with four form or organ genera from the Upper Mississippian (Chester Series) of the Illinois Basin, and provides evidence that they were produced by a single natural genus with gymnospermous affinity. The plant remains—compressions, impressions, petrifactions, and specimens that combine compression or impression with petrifaction—allow examination of both external morphology and internal anatomy. The specimens include foliage corresponding to Rhodea, stems and petioles corresponding to Heterangium, and synangiate fructifications corresponding to either Telangium or Telangiopsis. The stems and foliage are considered parts of the same plant because of the identity of the anatomical and cuticular features of petioles attached to stem and those petioles with attached foliage. The fertile material is regarded as part of the same plant because: (1) The anatomy of axes of the fertile specimens is like that of the sterile specimens. (2) A single specimen may contain both sterile Rhodea-type axes and fertile regions. (3) Axes bearing synangia have the same size and patterns of divisions as the sterile foliage. Features that indicate lyginopterid affinities include: (1) Equal forking of the petiole. (2) Presence of fiber bands in the outer cortex and sclerotic nests in the inner part of the cortex. (3) Crowded circular bordered pits on the lateral walls of the metaxylem tracheids. (4) The presence of a small amount of secondary xylem. A variety of structural details of the stem and petiole suggest the genus Heterangium. The phyletic position of the plant that produced Rhodea, Telangium, Telangiopsis, and Heterangium is reviewed in light of such discoveries as the presence of a planated frond that lacks a lamina and the presence of both monolete and trilete microspores in a single synangium.     

The Mississippian Tetrapod Footprint Ichnogenus Palaeosauropus: Extramorphological Variation and Ichnotaxonomy

Palaeosauropus primaevus is a tetrapod footprint ichnotaxon first described from the Upper Mississippian (Visean) Mauch Chunk Formation near Pottsville, Pennsylvania, United States. Our relocation of the type locality and stratigraphic horizon of P. primaevus, a long-available but unstudied collection of tetrapod footprints from these strata, and our new collections allow a much fuller characterization of this ichnotaxon and the range of extramorphological variation encompassed by it. P. primaevus is characterized as the footprints of a quadruped with a pentadactyl pes and a tetradactyl manus, in which the pes frequently oversteps the manus and with which tail drags are common. In the manus, all digits are relatively broad and have rounded tips, digit III is longest, and digit IV is more widely separated from digit III than the other digits are from each other. The pes has five digits that are also wide and blunt-tipped, digit IV is longest, and digit V projects nearly laterally. P. primaevus is the track of a relatively large temnospondyl (～400 mm gleno-acetabular length) and documents the Mississippian presence of such large amphibians long before their body fossil record. Palaeosauropus also occurs in Mississippian strata in Indiana and is distinguished from the geologically younger but similar temnospondyl footprint ichnogenus Limnopus by its relatively narrower manus and pes that lack broad and rounded sole impressions.     

STUDIES OF PALEOZOIC FERNS: THE FROND OF ANKYROPTERIS GLABRA

Eggert , Donald A. (Southern Illinois U., Carbondale.) Studies of Palerzoic ferns: The frond of Ankyropteris glabra. Amer. Jour. Bot. 50(4): 379–387. Illus. 1963—The major features of the frond of A. glabra are described on the basis of preserved parts found in Middle Pennsylvanian coal ball material from Illinois. The frond is planated and has well-developed foliar laminae. Primary pinnae arise from the petiole in 2 alternating series, and secondary pinnae arise in a similar fashion from the primary pinnae. Foliar laminae occur on the secondary pinnae and have dichotomous venation. The xylem of the petiole has a diupsilon configuration in the lower part of the axis, while higher in the petiole the xylem forms a strand resembling that of the European species A. westfaliensis. The xylem strands of the primary pinnae arise from the adaxial antennae of the petiolar vascular strand as somewhat C-shapcd bodies and develop antennae and become H-shaped at higher levels. A gap occurs in the antenna of the petiole vascular system above the level of departure of the primary pinna trace. Terete vascular strands occur in the secondary pinna axes which arise from the adaxial antennae of the xylem of the primary pinnae. The foliar laminae are relatively thin, have an irregular outline, and their histology is like that found in many living ferns. The frond of A. glabra illustrates that leaf evolution had progressed in at least one species of the coenopterid family Zygopteridaceae to the extent that an essentially 2-dimensional frond of modern aspect, and with well-developed foliar laminae, was present by Middle Pennsylvanian time.     

A new genus of Early Devonian plants with novel strobilar structures and vegetative appendages from the Posongchong Formation of Yunnan,China

A new plant, Dibracophyton acrovatum gen. et sp. nov., is described from the Lower Devonian (Pragian) Posongchong Formation of Wenshan District, southeastern Yunnan, China. The plant has creeping axes from which arise vegetative and fertile axes. The vegetative axes helically bear lateral dichotomous appendages with curved or round tips. The fertile axes possess terminal strobili with numerous fertile units arranged in irregular helices. Each fertile unit consists of a stalked long-elliptical sporangium, with dehiscence into two equal valves, and two discrete long-ovate bracts covering sporangium from above–below directions. A new genus and species is thus established based on these characters and is temporarily regarded as incertae sedis of Tracheophyta, although it perhaps closes to the barinophytes in affinity. Detailed comparisons with other plants having a similar architecture, i.e., sporangia closely associated with modified vegetative structures, are made. The discovery of D. acrovatum further enriches the composition of the Posongchong flora and demonstrates great morphological disparity of the Early Devonian vascular plants.     

Temporal variations of vegetative features, sex ratios and reproductive phenology in a Dictyota dichotoma (Dictyotales, Phaeophyceae) population of Argentina

This paper addresses the phenology of a Dictyota dichotoma population from the North Patagonian coasts of Argentina. The morphology of the individuals was characterized, and analyses of the temporal variations of vegetative features, diploid and haploid life cycle generations and sex ratios are provided. Individuals, represented by growing sporophytes and gametophytes, occurred simultaneously throughout the year. Morphological variables showed temporal variation, except the width and height of medullary cells, which did not vary between seasons. All vegetative variables were significantly correlated with daylength. Besides, frond length, frond dry mass and apical and basal branching angles were significantly correlated with seawater temperatures. Vegetative thalli were less abundant than haploid and diploid thalli. Sporophytes were less abundant than male and female gametophytes. Male gametophytes dominated in May, August, October and January, and female gametophytes were more abundant in September, November, December, February and March. The formation of female gametangia showed a significant correlation with daylength, and the highest number of gametangia was registered in spring. In general, the male/female sex ratio varied between 1:2 and 1:1. Apical regions were more fertile than basal regions. Our data about frequency in the formation of reproductive structures and male/female ratios are the first recorded in the Dictyota genus and thus could not be compared with populations from other regions of the world. Significant morphological variation was observed in thalli of both life cycle generations, regarding length and dry mass, number of primary branches and branching basal angle. In general, all variables analyzed varied seasonally except cortical cell width.