首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
A new taxon is described from the Upper Devonian, Oneonta formation in the northern Cats-kills of New York. Triloboxylon gen. n. is represented by petrifactions showing two orders of branching. The main axis bears branches spirally and the latter bear the ultimate appendages spirally. Ultimate appendages branch dichotomously twice, in one plane. Primary xylem of the main axis and branches is three-armed with mesarch protoxylem extending in a continuous band within each arm. Primary xylem of the ultimate appendage is terete and dichotomizes twice. Metaxylem elements are characterized by scalariform and circular-bordered pitting on all walls. The cortex is composed entirely of isodiametrical parenchyma cells. Triloboxylon is compared with other genera with three-lobed protosteles. Its possible affinity with the Aneurophytales is shown. The morphological nature of the “frond” of the Aneurophytales and the possibility that the group possesses the morphological equivalent of simple leaves are discussed.  相似文献   

2.
A review of the history of the genus Psilophyton is presented. Two new species with sporangia in organic connection, P. microspinosum and P. dapsile, are described. They are compared with Psilophyton-like plants from Maine and other previously described fertile species of this genus. Evidence from several species in the Trout Valley flora confirms the concept of this taxon as presented by Hueber and Banks. Data based on all sporangium-bearing species of Psilophyton are outlined, certain evolutionary trends within the taxon are tentatively presented, and recommendations for the treatment of the numerous fragmentary species and future new species are suggested.  相似文献   

3.
A new genus from a Middle Devonian locality near Cairo, N. Y., is described. Actinoxylon gen. nov. is based upon pyritic petrifactions. Three orders of branching are present: penultimate branch, ultimate branch, and leaf. The penultimate branch bears spirally arranged ultimate branches and leaves, the leaves apparently replacing the branches in the spiral. The ultimate branches bear opposite to subopposite and decussate leaves. The leaves are non-planated, unwebbed structures which show at least three dichotomies. Each segment of the leaf is terete as are all other axes. Internally the penultimate branch has a six-lobed actinostele with mesarch protoxylem areas, one or two per lobe. Secondary xylem is visible in the oldest parts of several specimens. The xylem has helical-reticulate, reticulate, scalariform and circular-pitted elements. The presumptive areas of phloem are occupied by cells with dark contents. The cortex is composed of a parenchymatous inner region and a sclerenchymatous outer region. The ultimate branch traces are at first three-lobed protosteles, later becoming four-lobed. Several ultimate branch traces also possess secondary xylem while within the cortex of the penultimate branch. The leaf traces are terete strands. Below each forking of a leaf segment there is a corresponding forking of the vascular strand. Actinoxylon is compared with the progymnosperms Actinopodium, Svalbardia, Archaeopteris, Siderella, and Tetraxylopteris. The anatomy of the penultimate branch of Actinoxylon is similar to that of Actinopodium, Archaeopteris macilenta, and Siderella. The ultimate branch traces of Archaeopteris and Actinoxylon are similar. The ultimate branch stele and pattern of trace formation in Actinoxylon is similar to the stelar configuration and trace formation in the r + 2 axes of Tetraxylopteris schmidtii. The unwebbed leaves are similar to those of Archaeopteris fissilis, Svalbardia, and the terminal units of the Aneurophytales.  相似文献   

4.
本报道的鱼类化石产自湖南石门大京州的上泥盆统写经寺组。在中国泥盆纪地层分区上,化石产地属于华南区的湘、鄂、川交界分区(侯鸿飞等,1988)。该分区泥盆系为一套厚度不超过500m的近岸海相碎屑岩沉积,仅发育中泥盆统上部至上泥盆统(图1),并普遍超覆在志留系温洛克统之上,以角度不整合伏于石炭系或二叠系之下。上泥盆统分两个组,从下而上分别为黄家磴组和写经寺组。黄家磴组系杨敬之、穆恩之(1953)创立,标准地点在湖北长阳马鞍山东端的黄家磴。岩性为砂岩夹少量页岩,植物化石丰富,并含有误订为植物化石的湖北长阳鱼(Changyanophyton hupeiense Sze,1952)。根据植物化石组合面貌,黄家磴组的时代被认为是晚泥盆世早期。写经寺组是谢家荣、刘季辰(1927)创立的。岩性分为二段:下段以泥灰岩为主,含Yunnanella abrupta、Yunnanellina triplicata等腕足类化石;上段以砂页岩为主,含植物化石,其组合面貌除大致与黄家磴组相似外,还有一些新的分子,如Leptophloeum guanzhuangense、Cyclostigma hunanense等。根据动、植物化石群的性质,写经寺组的时代大致与法门期早期相当。多年来,在这一分区的泥盆纪地层里,很少鱼类化石。杨敬之、穆恩之(1953)曾提及在湖北长阳写经寺组底部发现的鱼化石,这些鱼化石与腕足类Yunnanella、Tenticospirifer等共生,但种属并未定出。已记述过的鱼化石只有湖北长阳黄家磴组的长阳鱼(潘江,1962)。  相似文献   

5.
Abstract:  The supposed polychaete annelid Protonympha salicifolia , from the Upper Devonian (Frasnian) of New York State, USA, is redescribed. P .  salicifolia has a bilateral and segmented body, but appears to have a 'mattress-like' construction with blade-like extensions along the margins. The affinities of P. salicifolia remain unresolved, but a proposed relationship to the annelids is unlikely. The preservation of the three known fossils, as mouldic imprints in sandstones, is strongly reminiscent of the circumstances associated with Ediacaran fossilization, and as such is an anomalous occurrence of such soft-part preservation in Phanerozoic sediments. Material associated with these enigmatic fossils has been referred to Palaeochaeta devonica , and also compared with the annelids. Such an assignment is also rejected. These fossils appear to be arthropodan, and are possibly myriapods. A supposed example of Protonympha (' P '.  marcellensis ) from the Middle Devonian of New York State is now excluded from this genus, and it may be a crustacean.  相似文献   

6.
The leaf of mid Devonian Archaeosigillaria vanuxemii from Gilboa, N.Y. is known to have a thick conical base. This study demonstrates by the uncovering technique the attachment of leaves to the stem, the flattened lamina that is deltoid in outline with a toothed margin, and an apex prolonged into a hair. Comparisons are made with specimens from Kazakhstan. The morphology of leaves of other species of Archaeosigillaria and the slowly accumulating data on leaves of Devonian lycopods are discussed.  相似文献   

7.
Svalbardia banksii sp. nov., is described from the Upper Devonian (Frasnian) Fish Cabin Creek locality near Pond Eddy, New York. The compression consists of ultimate branches bearing spirally arranged, unwebbed leaves. The unwebbed leaves are up to 3.2 cm long, are somewhat flexuous, and dichotomize in more than one plane. The new species is similar to the reconstruction of Actinoxylon banksii from the Middle Devonian (Givetian) of New York and strengthens the supposed relationship between Svalbardia polymorpha and Actinopodium nathorstii from Mimerdalen, Spitzbergen.  相似文献   

8.
9.
In 1950,some interesting specimens of small trilobites have been forwardedthe writer for examination by Prof.C.C.Y(?) which form the subject of the presentcommunication.The specimens were collected by Prof.Y(?) from the PisoliticLimestone Series near Fonglingshan,Lingchuan-Hsien,Kwangsi province.The trilobite fossils were found in association with some ostracods and smallChonetes.The ostracods have been recently identified by Y.T.Hou as Richterinasubstriatula Hou,R.subhemisphaerica Hou and Healdia lingchuanensis Houassigning to the Upper Devonian age.It is interesting that the evidence of thetrilobites points also to the Upper Devonian age.  相似文献   

10.
Stenokoleos is a genus for petrified axes from the Mississippian New Albany Shale to which an Upper Devonian occurrence in New York is added. Two orders of branching were known and the plant was thought to be related to coenopterid ferns. The new petrified axes from New York reveal three orders of branching. A pair of rachides emerges from one side of the stem at each node. Their position alternates at successive nodes (distichous). Each rachis bears alternately arranged pinnae. The shape of the xylem strand and the number of protoxylem areas are variable. Traces to the pairs of rachides arise either as two separate strands or as a single strand that is presumed to divide while still within the cortex of the stem. Traces to pinnae are ellipsoid or clepsydroid. Tracheids are scalariform and uni- or biseriate, circular-bordered pitted. Peripheral loops are present in all orders of branches. Protoxylem strands are numerous and maturation is mesarch. Cortex is parenchymatous where it is preserved but outer cortex is missing. Stenokoleos and Reimanniopsis are placed in a new family, Stenokoleaceae. This is classified as Incertae Sedis among Pterophytina in Tracheophyta. It is suggested that the plant is related more closely to the Mississippian pteridosperms Tristichia and Tetrastichia than to the coenopterid ferns.  相似文献   

11.
The presence of paracytic stomata and paired guard cells on specimens presumed to be Drepanophycus spinaeformis Göppert from eastern Canada and New York State supports the conclusion of Banks and Grierson that the species is not a reliable index of Lower Devonian strata. The interpretation of stomatal morphology demonstrates that the species lived in Early, Middle, and Late Devonian time and that slender specimens are distinct from zosterophylls such as Sawdonia that had anomocytic stomata and a single guard cell. Knowledge of the stomata also permits a reinterpretation of the stomatal apparatus as first described by Lang. Siegenian specimens of the genus apparently represent the oldest occurrence of paired guard cells and of paracytic stomata.  相似文献   

12.
徐洪河  王怿 《古生物学报》2002,41(2):251-258
描述新疆和布克赛尔晚泥盆世洪古勒楞组中的一种石松类孢子囊穗,该孢子囊穗二歧分叉一次,长纺锤形叶座紧密螺旋排列于穗轴上,每轮6枚;孢子叶披针形,具叶柄,单脉,叶缘具细齿;孢子囊近轴处着生,长椭球形,囊内有4枚大孢子;大孢子圆球形,表面光滑,直径为900-1200μg。通过对比研究,将当前孢子囊穗定为新属、新种,即Hefengistrobus bifurcus gen.et sp.nov.,同时讨论该孢子囊穗在石松类演化上的意义。  相似文献   

13.
描述泡沫轴珊瑚属一新种———Aphraxoniawuqiaensissp .nov .,标本产于沿新疆南天山地区乌恰县托帕 吐乐尕特山口公路边的中泥盆统托格买提组。泡沫珊瑚属过去仅在土耳其Anatolia地区和我国湖南株州地区发现 ,目前在新疆中泥盆统的发现 ,不仅丰富了该属的化石种资料 ,同时也表明在中晚泥盆世南天山地区可能与土耳其Anatolia地区和华南地区存在密切的生物地理区联系。通过与该属已知 2个种特征和产出时代的对比 ,看出从中泥盆世Givetian期到晚泥盆世 ,可能存在从A .zhuzhouensis→A .wuqiaensissp .nov→A .taurensis的演化谱系和由华南→新疆南天山→土耳其的迁移路线。其演化趋势体现为 :1 )一级隔壁数目逐渐减少 ;2 )隔壁由中部加厚→边缘加厚 ;3)主、对隔壁分离 ,对隔壁伸过中心形成轴端微膨胀板状中轴→轴端膨胀明显的板状中轴→主、对隔壁在中心交汇形成轴端膨胀中轴 ;4 )一级隔壁不达中轴→与中轴相交。  相似文献   

14.
15.
我国泥盆系鱼化石非常丰富,尤其是下、中泥盆统。但是,上泥盆统鱼化石发现尚少,而且主要是胴甲类化石,节甲类化石则很少发现。潘江(1962)在对斯行健已记述的一植物化石 Changyanophyton hopeiensis Sze重新进行观察时认为,该化石应属于盾皮鱼类,并将其归人瓣甲类 Macroptetalichthyidae(?),化石仅包括前腹侧片和胸棘。 Denison(1978)根据潘江的文章和插图则认为, Changyanophyton hupeiensis属于原始节甲类或者瓣甲类。王念忠等…  相似文献   

16.
New specimens of Triloboxylon ashlandicum Matten and Banks (1966) show additional features of the anatomy and morphology of the plant. The primary xylem has strands of parenchyma associated with trace formation. Secondary xylem and phloem are described for the first time. The outer cortex, previously unknown, contains hypodermal fiber strands. The ultimate appendages are much divided and planated. Specimens of Aneurophyton hallii (Arnold, 1940) were reexamined and newly prepared. They are transferred to the genus Triloboxylon as T. hallii. Triloboxylon is transferred from Pteropsida-Incertae Sedis to the Aneurophytales. New information on the morphology and anatomy of Telraxylopteris is presented and its identity to Sphenoxylon is supported.  相似文献   

17.
Abstract:  Additional material of a large specimen of tristichopterid fish from the Upper Famennian Evieux Formation of Belgium is described. This large fish was previously assigned to Tristichopteridae gen. et sp. indet. due to the lack of diagnostic anatomical data. New available material consists of the internal surface of the parietal shield, vomers and anterior part of the parasphenoid, subopercular and submandibulo-branchiostegal bones, and an internal view of the anterior part of the mandible. A possible autapomorphy of the new form from Belgium, Langlieria socqueti gen. nov. et sp. nov., is the absence of marginal teeth on the vomer except on its most lateral part. Apart from these features, it only differs from the genus Mandageria from Australia in the absence of marginal teeth between the dentary fang and the mandibular symphysis, in the presence of a raised marginal crest lateral to the anterior coronoid fang, and in the presence of numerous small marginal teeth on the premaxilla. It differs from the cosmopolitan genus Eusthenodon in a number of respects: the supratemporal, tabular, and postparietal bones are superficially fused, as are the intertemporal and parietal bones, the dermal ornament is proportionally very fine, and the denticulated field of the parasphenoid stands proud rather than being recessed into the body of the bone.  相似文献   

18.
Campbell, J. D. (Res. Council Alberta, Edmonton.) Callixylon from the Upper Devonian of northwestern Alberta. Amer. Jour. Bot. 50(7): 648–652. Illus. 1963.—An oil-well core from the “Granite Wash” of probable early Late Devonian age (Wood bend equivalent) in the Peace River region of northwestern Alberta yielded a thin pyritized chip of coniferoid wood. The pith is not represented, but the secondary tracheid pitting, exhibiting radially aligned clusters of 5–10 araucarioid pits, indicates that the specimen is referable to the wood-type usually called Callixylon, now believed to be the axis of the leaf-genus Archaeopleris. In its low and regularly uniseriate or rarely biseriate rays, with no apparent ray tracheids, the specimen may resemble the species Callixylon trifdievi Zalessky (1909) from the Upper Devonian of Russia, and thus lend some small support to the postulation of a Late Devonian land connection between northwestern North America and Europe.  相似文献   

19.
Specimens of Calamophyton from the Middle Devonian Ashokan Sandstone near Kingston, Ulster County, N.Y., are shown to belong to C. bicephalum Leclercq and Andrews, a Belgian species. Steel needles and a stereoscopic binocular microscope were used to follow the path of the forking leaves and branching sporangiophores of the specimens through the matrix. The terete leaves dichotomized two to three times in more than one plane. Sporangiophores dichotomized once. Each branch bore three recurved lateral branches which in turn bore two sporangia. Each branch terminated in an elongate, filiform projection. Sporangia apparently dehisced longitudinally. Their walls were composed of elongate cells. Their spherical spores ranged from 86 to 166 μ in diameter and bore a trilete mark. Ornamentation consisted of coni and spinae up to 4.5 μ long. They resembled dispersed spores of Dibolisporites gibberosus var. major Richardson. This is the second occurrence of Calamophyton bicephalum and the first account of its spores. It is the second report of the genus in North America.  相似文献   

20.
Proteokalon gen. nov. is described from the Upper Devonian Catskill deposits of New York. Two orders of branching and ultimate appendages are preserved' by petrifaction and by compression. The first order bears branches decussately and has a skewed four-armed protostele that occasionally dichotomizes. Second-order branches dichotomize rarely and most have T-shaped or three-armed protosteles. They bear ultimate appendages alternately, either in lateral pairs, or singly from the abaxial side. These appendages divide several times in one plane. Their vascular strand is terete. Maturation of the primary xylem is mesarch, and it consists of tracheids and parenchyma. Secondary xylem and phloem and a periderm are present. The outer cortex has a system of hypodermal fibers. Proteokalon is most similar to Tetraxylopteris and Triloboxylon of the Aneurophytales. A comparison of the stratigraphic occurrence of Protopteridium, Aneurophyton, Tetraxylopterism, Sphenoxylon, Triloboxylon, and Proteokalon suggests some evolutionary trends among the Aneurophytales.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号