湖北长阳上泥盆统一种石松植物

描述一种采自湖北上泥盆统弗拉阶黄家蹬组中的石松植物。该植物茎轴纤细。叶基纺锤形,螺旋排列。叶线形,叶缘具刺。具顶生的孢子叶球。其孢子叶匙状或披针形,边缘具刺。孢子囊呈圆形或椭圆形。植物茎具原生中柱。原生木质部呈小脊状位于中柱边缘。后生木质部管胞由梯纹分子组成,在加厚棒之间没有类似“威廉姆逊纹”的连接物。该植物与采自湖南中泥盆统基维特阶的Longostachys(Zhu,Huand Feng) Caiand Chen可比较。它们在茎轴、线形和具刺的叶、纺锤形和螺旋排列的叶基、匙状披针形的孢子叶,以及叶、叶基和孢子叶的度量等特征方面均非常相似。两者在解剖特征上存有差别,即当前植物不具次生木质部,不具髓,后生木质部加厚棒之间不具连接物。考虑到现有特征并不足以建立新属种,暂归入cf.Longostachyssp.     

ARCHAEOPTERIS MACILENTA,ANATOMY AND MORPHOLOGY OF ITS FROND

The stem, rachides, and pinnae of Archaeopteris macilenta, formerly considered to be a fern of Devonian age, comprise a branch system in which the ultimate divisions heretofore referred to as pinnules are the leaves. The primary vascular system of the “frond” is a lobed siphonostele from which leaf traces arise in a spiral sequence. The anatomy of the “rachis” and of the “pinnae” is shown to be similar to that of the stem, Callixylon, which bore these “fronds.” Branching, epidermal pattern and stomates are described for the spirally arranged leaves (fertile pinnules). Attachment and dehiscence of sporangia as well as their stomates are reported. Archaeopteris is retained in the Class Progymnospermopsida which includes plants with gymnospermous anatomy and pteridophytic reproduction. It is suggested that Actinopodium, Svalbardia and Siderella are related closely to Archaeopteris and that this group of genera shows evolutionary stages in webbing of leaves and planation of branch systems. The opportunities for ontogenetic studies of the arborescent genus Archaeopteris are pointed out.     

A probable pteridosperm from the uppermost Devonian near Ballyheigue, Go. Kerry, Ireland

A new genus of pleridosperms is described from the uppermost Devonian beds from Ballyheigue, Ireland. I.aceya hibernica May & Mat ten is represented by stems bearing spirally arranged fronds. The base of the frond is swollen and is about the same size as the stem. Pinnae are borne alternately and apparently in one plane on the rachis. The anatomy of the stem reveals a three-fluted protostele. Secondary xylem consists of rays and trachcids and secondary phloem is present. The inner cortex contains probable secretory and/or sclerotic cells. The outer cortex is of the spargaimm-type. Rachial trace formation is described. The U-shaped xylem strand of the rachis lacks secondary tissue. Pinnae traces are V- to C-shaped. A presumed adventitious root has a triarch protostele, a parenchymatous cortex and lacks a 'sparganum' outer zone. I.aceya is believed to be a member of the Lyginopleridaceae. The divisions of the sympodial protoxylem strand forming the rachial trace is compared among the Aneurophytales, Buteoxylonaceae, Calamopityaceae and Lyginopteridaceae and is shown to be similar.     

NEW DISCOVERY OF YUNNANOLEPIDS- HETEROYUN-NANOLEPIS QUJINCENSIS (GEN. ET SP. NOV.)

Thenewformdiffersfromtlieotheryunnanolepidsinthefollowingcharacteristics:1)orbitalfenestrabiggerandinamoreanteriorposition;2)possessingpreorbitalrecess(prh)insteadofpreorbitaldepression;3)infraorbitalsensorycanalpassingthroughpostmarginalplate;supraorbitalsensorycanalonpost-pinealplate;4)posteriorinternaltransversecrestinamoreposteriorposition.Onthebasisofcharactersofthenewgenus,thefollowingconcludingremarksarepreliminarygiven:1)Thepreorbitaldepressioninyunnanolepidsisprobab1ynothomologouswith…     

Comparative anatomy of secretory structures of leaves in Hypericum L.

The structure, type, morphology and location of secretory structures in leaves of 43 species, 1 subspecies and 1 variety of 9 sections in Hypericum L. were comparatively studied using tissue clearing, paraffin sectioning and thin sectioning. The results have shown that the presence of secretory structures is a common feature of leaves in this genus. According to their anatomical characteristics, the secretory structures can be divided into nodules, secretory cavities (canals) and tiny secretory tubes. In their distribution in leaves the nodules fall into two types: the leaf edge type and the scattered type. According to the location of cavities in the cross sections of leaves, the cavities can be divided into 4 types: the median type which is situated between the palisade tissue and spongy tissue, the palisade tissue type, the spongy tissue type and the across-mesophyll type. Based on the location of cavities and nodules in leaves, the species in Hypericum can be divided into 3 groups: group Ⅰ , in which only cavities are present; group Ⅱ, in which only nodules are present; group Ⅲ, in which both cavities and nodules are present. The type, location, distribution density and morphology of secretory structures are of some taxonomic value at the level of species and of section in Hypericum L. From these observations, the evolutionary trends concerning the morphology and anatomy of secretory structures and the affinity among sections in the genus Hypericum ate dis-cussed.     

A new plant with novel leaves from the Upper Devonian of Zhejiang Province,China

The evolution of vascular plants during the Devonian Period has had great impacts on terrestrial ecosystems through innovations of key characters such as leaves, heterospory, seed reproduction, and woods. Here we report a new plant, Qianshouia mira n. gen. n. sp., from the Upper Devonian Wutong (Wutung) Formation of Fanwan section, Changxing County, Zhejiang Province, China. This plant has slender axes which seldom branch. Its leaves are arranged in pseudowhorls, departing from axes with an acute angle. The leaves are strap-shaped and each can be subdivided into proximal, middle and distal portions. At the proximal portion, a middle ridge develops, and at the middle portion this ridge divides at least three times forming four to six daughter ridges, and in between are grooves. The distal portion of leaves (leaf apex) is suggested to be adaxially curved, with no ridges but with forked tips. Qianshouia probably represents a small plant with a shrubby or herbaceous habit. Due to the unique leaf morphology and the lack of fertile structures and anatomy, the exact phylogenetic position of Qianshouia is uncertain. Qianshouia might be a lycopsid in light of the pseudowhorled phyllotaxis, or alternatively, could be a sphenopsid if the dichotomous ridge system of the leaf could be demonstrated to be leaf veins. Nevertheless, Qianshouia adds to the diversity of leaf morphologies among the Late Devonian vascular plants.     

The foliicolous lichen flora of Mexico IV: a new, foliicolous species of Pyrenothrix (Chaetothyriales: Pyrenothrichaceae)

Pyrenothrix mexicana Herrera-Campos, Huhndorf & Lücking spec. nova is described from leaves in the upper montane rainforest of Oaxaca State, Mexico. It is the second species in the genus Pyrenothrix Riddle, established at the beginning of the twentieth century for the single species, P. nigra Riddle, a corticolous lichen restricted to southeastern United States. Both taxa have the same thallus and perithecial morphology and anatomy, but P. mexicana differs by its longer, transversally septate ascospores. The perithecial anatomy of Pyrenothrix is documented and its systematic affinities are discussed, and we conclude that the family Pyrenothrichaceae Zahlbr. should be placed in the order Chaetothyriales.     

Teranota n. gen. (Bivalvia; Anomalodesmata) aus dem Mittel-Devon (Givetium) des Rheinischen Schiefergebirges

From the Rhenish Middle Devonian (Givetian) a new genus of posteriorly extremely elongated, endobenthonic bivalves preserved in life orientation is described. The phylogenetic relationships within the superorder Anomalodesmata are discussed.     

New Sphenophyllum plant from the Upper Devonian of Zhejiang Province,China

Sphenophyllum was an important and long-surviving sphenopsid genus in the Paleozoic floras, with a worldwide distribution. A new species, Sphenophyllum changxingense sp. nov., is described from the Upper Devonian Wutong Formation of Changxing County, Zhejiang Province, China. This plant is characterized by two orders of slender axes and wedge-shaped leaves borne in whorls. The axes bear short spines and show longitudinal ridges and furrows on surface. Three to eight isophyllous leaves, with one, two, or no second-order axes, are attached at each node of first-order axes. Leaves bear spines and show a bilobate morphology; the two leaf lobes divide distally to form several marginal segments, each segment with a leaf vein. Sphenophyllum changxingense represents an early and primitive species within the genus, in light of the absence of heterophylly and specialized hook-like leaves. Like some Carboniferous and Permian species, it appears to have formed dense mats with mutually supportive axes. This plant adds to the known diversity of early sphenopsids in the Late Devonian.     

Occurrence and forms of Kranz anatomy in photosynthetic organs and characterization of NAD-ME subtype C4 photosynthesis in Blepharis ciliaris (L.) B. L. Burtt (Acanthaceae)

Blepharis (Acanthaceae) is an Afroasiatic genus comprising 129 species which occur in arid and semi-arid habitats. This is the only genus in the family which is reported to have some C(4) species. Blepharis ciliaris (L.) B. L. Burtt. is a semi-desert species with distribution in Iran, Oman, and Pakistan. Its form of photosynthesis was investigated by studying different organs. C(4)-type carbon isotope composition, the presence of atriplicoid type Kranz anatomy, and compartmentation of starch all indicate performance of C(4) photosynthesis in cotyledons, leaves, and the lamina part of bracts. A continuous layer of distinctive bundle sheath cells (Kranz cells) encircle the vascular bundles in cotyledons and the lateral vascular bundles in leaves. In older leaves, there is extensive development of ground tissue in the midrib and the Kranz tissue becomes interrupted on the abaxial side, and then becomes completely absent in the mature leaf base. Cotyledons have 5-6 layers, and leaves 2-3 layers, of spongy chlorenchyma beneath the veins near the adaxial side of the leaf, indicating bifacial organization of chlorenchyma. As the plant matures, bracts and spines develop and contribute to carbon assimilation through an unusual arrangement of Kranz anatomy which depends on morphology and exposure to light. Stems do not contribute to carbon assimilation, as they lack chlorenchyma tissue and Kranz anatomy. Analysis of C(4) acid decarboxylases by western blot indicates B. ciliaris is an NAD-malic enzyme type C(4) species, which is consistent with the Kranz cells having chloroplasts with well-developed grana and abundant mitochondria.     

New perspective on the architecture of the Late Devonian arborescent lycopsid Leptophloeum rhombicum (Leptophloeaceae)

A reinvestigation of the previously described Leptophloeum rhombicum trunk from the Late Devonian (Frasnian) Huangchiateng Formation of Hubei, China provides a new perspective on the architecture of this arborescent lycopsid. It is preserved as a flattened, silicified petrification with an unevenly permineralized primary vasculature and spirally arranged rhombic leaf cushions, which agree with the diagnosis of L. rhombicum Dawson distributed worldwide in the Late Devonian. Taxonomically, this plant should be assigned to its own family and within the order Iso?tales sensu lato. The anatomy, from different levels of the trunk, demonstrates that the ontogeny of the plant may conform to a determinate growth pattern. Combining previous data with current architectural analysis, it suggested that the L. rhombicum tree had a pseudomonopodial branching pattern rather than an iso-dichotomous branching crown as previously proposed. New reconstruction of the general habit for this tree is given and consists of three major architectural units: a stigmarian rhizomorph, a main trunk, and lateral branches. When these results are considered with recent cladistic work, L. rhombicum may have developed similar growth architecture to some Famennian and Carboniferous arborescent lycopsids. This growth represents one of the archetypal architectures found in the Iso?tales s.l. extending from the early Late Devonian.     

New insights into the heterosporous lycopsid <Emphasis Type="Italic">Changxingia</Emphasis> from the Upper Devonian Wutong Formation of Zhejiang Province,China

A heterosporous lycopsid plant is described from the Upper Devonian (Famennian) Wutong Formation, Changxing County, northern Zhejiang Province, China. The plant is known for its terminal and many detached megasporangiate strobili, most of which do not have sporophylls preserved. Some megasporangiate strobili are closely associated with a vegetative axis bearing leaf cushions and with a mass of microspores. Because of the monosporangiate strobili, the present lycopsid belongs to the Dichostrobiles of the Isoёtales sensu lato. This lycopsid conforms to Changxingia in the vegetative leaves, leaf cushions (including leaf scar and ligule pit), some parts of the megasporophyll (pedicel, heel and lamina), the megasporangium and the megaspores, although the branching pattern of axes, the arrangement and other parts of megasporophyll are still unknown. The fossils are described as Changxingia sp., and this genus is expanded with character of microspore. Hence, the previous and present data indicate that the earliest lycopsids with monosporangiate strobili from the Upper Devonian of China are consistent in Lagenicula megaspores with gula and Lycospora microspores with equatorial cingulum. In contrast, the Carboniferous lycopsids with monosporangiate strobili in Euramerica and Cathaysia show great diversification of both megaspores and microspores.     

Chondrocranial, hyobranchial and internal oral morphology in larvae of the basal bufonid genus Melanophryniscus (Amphibia: Anura)

Melanophryniscus is a genus of small toads inhabiting the southern portion of South America. This genus is considered basal within the family Bufonidae. Data on larval chondrocranial morphology do not exist for the genus and larval internal oral anatomy has only been described for a single species. Here, we describe chondrocranial and internal oral morphology in Melanophryniscus montevidensis , M. orejasmirandai and M. sanmartini . Chondrocranial morphology is similar among the species examined. Comparisons with other bufonids and with outgroup taxa suggest that the following chondrocranial characters may represent synapomorphies for the Bufonidae: free (or absent) ceratobranchial IV, a reduced or absent larval crista parotica, the lack of a larval otic process, and late development of thin, poorly chondrified orbital cartilages. The presence of an elongated processus anterior dorsalis of the suprarostral alae and the absence of a chondrified commissura quadratoorbitalis appear to be unique in Melanophryniscus among bufonids. Internal oral anatomy is conserved in Melanophryniscus , and among bufonids in general.     

Ellesmeris sphenopteroides,gen. ET SP. NOV., a new zygopterid fern from the Upper Devonian (Frasnian) of Ellesmere,N.W.T., Arctic Canada

A new fern-like fossil plant is described from the lower Upper Devonian of southern Ellesmere Island, Canadian Arctic Archipelago. The plant occurs in an Archaeopteris-dominated flora preserved in the Nordstrand Point Formation (Mid-Late Frasnian) near Bird Fiord. The plant has a pinnate vegetative system with three branch orders and laminate sphenopteroid pinnules. Primary pinnae usually diverge from the main axis in distichous pairs (quadriseriate), but can depart singly (biseriate). Each primary pinna bears a basal catadromic aphlebia. Anatomically, the plant exhibits a mesarch, bipolar protostele that is ribbon- to clepsydropsoid-shaped in the main axis. Primary pinna traces are also initially bipolar and crescent-shaped, but may become four-ribbed before dividing into a pair of bipolar traces. The morphology and anatomy of this plant are nongymnospermous and are most similar to Zygopteridales (particularly Rhacophytaceae and Zygopteridaceae). The Frasnian age of Ellesmeris shows that laminated foliage had evolved in some zygopterid ferns much earlier than previously recognized. The Sphenopteris-like pinnules of Ellesmeris indicate the need for caution when attributing such a convergent foliar design to other plant groups, such as the Devonian gymnosperms.     

Re-study of Minostrobus chaohuensis Wang (Lycopsida) from the Upper Devonian of Anhui,South China

Minostrobus chaohuensis Wang was previously known only as a lycopsid megasporangiate strobilus from the Upper Devonian of Anhui Province, South China. Our comprehensive study of the newly collected materials reveals the details of its morphology, anatomy, and reproduction, which allow us to emend its generic and specific diagnoses. M. chaohuensis is reconstructed as a plant with multi-dichotomous branching system, helically arranged leaves, and monoecious and monosporangiate strobili (i.e., separate megasporangiate and microsporangiate strobili in one individual). The anatomy of both fertile and sterile portions of Minostrobus indicates that the exarch primary xylem strand is the solid protostele, with the peripheral protoxylem ridges and Williamson's striations in metaxylem tracheids. The key reproductive and anatomical characters suggest that Minostrobus chaohuensis is far more likely to represent a distal shoot of pseudo-herbaceous or arborescent lycopsids within the order Isoëtales sensu lato. It is suggested that the monosporangiate-strobilus clade in the Isoëtales may include primitive, monoecious taxa in the Late Devonian and advanced, dioecious ones in the Carboniferous. The hypothesis that the more phylogenetically advanced monosporangiate-strobilus clade might have well diverged from the basal bisporangiate-strobilus clade of arborescent lycopsids by the Late Devonian is further supported.     

ZHAOTONGASPIS JANVIERI GEN.ET SP.NOV.,A GALEASPID FROM EARLY DEVONIAN OF ZHAOTONG,NORTHEASTERN YUNNAN

ThefirstearlyvertebratedescribedfromtheDevonianofZhaotong,northeast-ernYunnan(Fig.i),wasthegaleaspidSanqiaspiszhaotongensis(Liu,i975).Thefish-b6aringhorizonwasthoughttobelongtothe"CuifengshanFormation",thatis,Pragianinage,incomparisonwiththetypelocalityofthisformationintheQujingdistrict,Yunnan.Liaoctal.(l978)consideredthatitwouldbemoreappro-priatetonametheh0riz0nasthePosongchongFormation,sinceithasthesamelitho1ogyandfaunaastheP0s0ngchongFormationintheWenshandistrict,Yunnan.Thissuggesti0…     

FOLIAR MORPHOLOGY AND ANATOMY OF THE GIGANTOPTERID PLANT DELNORTEA ABBOTTIAE,FROM THE LOWER PERMIAN OF WEST TEXAS

Delnortea is a monotypic genus (type-species: D. abbottiae) of Lower Permian gymnosperms based on leaves from uppermost Leonardian deltaic sediments exposed in the Del Norte Mountains, West Texas. The leaves are simple, symmetrical, mostly oblong or elliptical, and vary in length from 1.2 to about 35 cm. The petioles are short and stout, with a basally enlarged abscission zone. The margins are crenate, with a narrow, indurated border. Venation is in 4 orders: the secondaries and tertiaries are robust, unbranched, and pinnately arranged in a precise “herringbone” pattern, with the secondaries ending in the marginal sinuses; the quaternaries divide sparingly and fuse with others to form a dense reticulum of small meshes. Permineralized petiole and midrib material reflects a bifacial cambium, shown by a semicircular vascular arc, irregularly divided into several collateral bundles with secondary xylem and phloem. Delnortea is referable to the Gigantopteridaceae, a probably artificial family of gymnosperms incertae sedis with important venation features in common, but without known diagnostic reproductive organs. With Delnortea, the North American gigantopterids now include 5 genera, but Gigantopteris itself is lacking. Delnortea holds a relatively advanced evolutionary position among the American gigantopterids; its leaf morphology and gymnospermous anatomy entail intriguing points of comparison with Gnetum. The limited geographic and stratigraphic ranges and morphological distinctiveness of the American gigantopterids and associated taxa attest to rapid evolution and dispersal from a small area of origin in the southwestern United States during Leonardian time.     

An exceptionally preserved Late Devonian actinopterygian provides a new model for primitive cranial anatomy in ray-finned fishes

Actinopterygians (ray-finned fishes) are the most diverse living osteichthyan (bony vertebrate) group, with a rich fossil record. However, details of their earliest history during the middle Palaeozoic (Devonian) ‘Age of Fishes'' remains sketchy. This stems from an uneven understanding of anatomy in early actinopterygians, with a few well-known species dominating perceptions of primitive conditions. Here we present an exceptionally preserved ray-finned fish from the Late Devonian (Middle Frasnian, ca 373 Ma) of Pas-de-Calais, northern France. This new genus is represented by a single, three-dimensionally preserved skull. CT scanning reveals the presence of an almost complete braincase along with near-fully articulated mandibular, hyoid and gill arches. The neurocranium differs from the coeval Mimipiscis in displaying a short aortic canal with a distinct posterior notch, long grooves for the lateral dorsal aortae, large vestibular fontanelles and a broad postorbital process. Identification of similar but previously unrecognized features in other Devonian actinopterygians suggests that aspects of braincase anatomy in Mimipiscis are apomorphic, questioning its ubiquity as stand-in for generalized actinopterygian conditions. However, the gill skeleton of the new form broadly corresponds to that of Mimipiscis, and adds to an emerging picture of primitive branchial architecture in crown gnathostomes. The new genus is recovered in a polytomy with Mimiidae and a subset of Devonian and stratigraphically younger actinopterygians, with no support found for a monophyletic grouping of Moythomasia with Mimiidae.     

A novel lycopsid from the Upper Devonian of Jiangsu, China

A new lycopsid, Monilistrobus yixingensis gen. et sp. nov., is described from the Wutung Formation (Famennian, Upper Devonian) of Jiangsu, China. The plant has many features typical of other Upper Devonian lycopsids, including dichotomous branching, helically arranged obovate expanded leaf bases, linear leaves with spiny appendages along the lateral margins, sporophylls widened proximally, and one elliptical sporangium attached to the adaxial surface. The most distinctive novel feature of the plant is that the modified sporophylls are arranged tightly into fertile zones or cone-like structures that are separated by lengths of axes with more lax sterile microphylls only: therefore the cone-like structures are strung along the branches like beads on a necklace.     

The herbaceous lycophyte Haskinsia Grierson and Banks from the Devonian of western Venezuela, with observations on leaf morphology and fertile specimens

The Devonian herbaceous lycophyte genus Haskinsia Grierson and Banks is characterized by narrow dichotomizing stems and helically arranged petiolate leaves with a broad, approximately deltoid, lamina. New specimens are reported from four horizons in the Lower Member of the Campo Chico Formation, Sierra de Perijá, western Venezuela. H. sagittaka Edwards and Benedetto has sagittate leaves, and fertile specimens are reported for the first time; the ellipsoidal/obovoid adaxially-flattened sporangium is attached to unmodified leaves towards the top of the petiole in the adaxial position. H. sp. has sagittate leaves which are larger than any yet attributed to the genus but is represented by only three specimens. H. hastata sp. nov. has hastate leaves; the sporangia are more globose but positioned similarly to those of H. sagittata. The occurrence of the sporangia on unmodified microphylls indicates that Haskinsia is a member of Protolepidodendrales. The status of Haskinsiaceae is discussed. The Venezuelan specimens are compared with other records of Haskimi and Haskinsia -like plants from North America, Kazakhstan, North China, North Africa and Antarctica.