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1.
Anatomically preserved fertile marattialean pinnules from the Lower Permian (Wolfcampian) Bursum Formation in Tularosa, New Mexico, and isolated synangia from the Upper Pennsylvanian (Missourian) Stanton Formation near Tyro, Kansas, are described. The sessile synangia are partially sunken into the pinnule lamina and arranged abaxially in a single row on each side of the midrib. Comparisons are made with other fossil and modern marattialeans and the evolutionary significance considered.  相似文献   

2.
Recently collected specimens of Danaeites rigida Gu and Zhi from the Upper Permian of south China have been subjected to detailed morphological investigations in order to reveal features of their fertile pinnules. The specimens are preserved as compression/impressions and possess pecopteroid-type pinnules with a single row of synangia on either side of the pinnule midvien. Individual synangia are bilaterally symmetrical, sessile, and their bases are embedded in the tissues of the pinnules. Synangia possess 18–24 sporangia that are laterally fused to one another throughout their entire length. Sporangial dehiscence is through a longitudinal slit and sporangia contain trilete spores with a granular ornamentation, referable to the dispersed spore Cyclogranisporites. This combination of characters is unique in specimens preserved by compression/impression although they are similar to those known in permineralized marattialean fertile fronds. However, anatomical details salient to the identification of these permineralized taxa are not identifiable in impression/compression fossils such as Danaeites. The taxonomic and phylogenetic implications of these findings are considered in detail and we conclude that Danaeites has closer links with Marattia than with Danaea.  相似文献   

3.
Telangium pygmaeum Graham is known from Upper Pennsylvanian coal balls from the Calhoun coal mine (Illinois). The species was described as possessing radial synangia consisting of 3-5 sporangia fused laterally for about f13 their length. Synangia were believed to be sessile and borne terminally or laterally on a branching rachis without lamina. Examination of new coal ball material of the same age indicates that the synangia are borne abaxially on the pinnules of a compound frond with the anatomy of a Psaronius leaf (Marattiales). Synangia are sessile and borne in two rows, one on either side of the pinnule midrib, under the unbranched lateral veins. Synangia are radial, 0.6 mm in diam, and consist of a ring of thin-walled sporangia fused to near their apices prior to dehiscence, but separating on dehiscence to release spores along their inner midline. Spores are spherical, trilete, 30-48 μm in diam, with a granulate ornamentation. The new genus Araiangium is proposed for this material based on the organization of the sessile thin-walled synangia. Araiangium is compared with other marattialean genera with sessile synangia (Acaulangium, Acitheca), and with the pedicellate synangia of various species of Scolecopteris. Criteria used in the delimitation of genera in Paleozoic anatomically preserved marattialean fertile foliage are discussed.  相似文献   

4.
Eoangiopteris goodii sp. n. is described from Upper Pennsylvanian coal balls from Ohio (Shade locality) containing isolated pecopterid pinnules approx. 7 × 9 mm that bear up to 20 linear synangia on the lower surface. The synangia extend at right angles from the midrib to the downturned pinnule margins and measure 2.0–3.5 mm in length. Individual synangia are compact and are composed of 10–19 sporangia that have their bases embedded in an elongate parenchymatous pad. In longitudinal section sporangia measure 0.4 × 2.0 mm and have acute elongate, curved apices. Spores average 70 μm in diam and are most similar to the dispersed spore genus Verrucosisporites. Eoangiopteris goodii differs from the generitype E. andrewsii Mamay in its greater size, pinnule histology, and spore type. Sporangium wall complexity and spore type of the two presently known species of Eoangiopteris are considered to be at about the same evolutionary level as the more primitive species of Scolecopteris. Construction of the synangia in Eoangiopteris is different from that of Scolecopteris and indicates that at least two evolutionary lines are recognizable within the Pennsylvanian Marattiales.  相似文献   

5.
A new species of the genus Telangiopsis, T. nonnae O. Orlova et Zavialova, was described on the basis of a microsporangiate organ from the Lower Carboniferous deposits of the Novgorod Region. The morphology of branching fertile axes, synangia, and sporangia was thoroughly studied. The three-dimensional system of fertile axes branches monopodially; ultimate axes bear numerous connivent bunches of synangia, which consist of three to six basally fused elongated ovate sporangia. The morphology and ultrastructure of prepollen grains were studied, which were extracted from the rock matrix surrounding the sporangia. The two-layered exine includes a well-developed endexine and an alveolate ectexine, with one-three rows of large thin-walled alveolae. The new species was compared with other Early Carboniferous microsporangiate organs.  相似文献   

6.
Scolecopteris Zenker, a kind of anatomically-preserved fertile foliage of Late Paleozoic Marattiales, has been well studied in Euramerican Flora. It is composed of 28 species which can be divided into four forms (groups) mainly based on modified or umodified pinnules, the variation of the outer facing sporangial walls, and with or without a prominent central parenchyma area. In contrast, Scolecopteris Zenker in Cathaysian Flora has been poorly studied so far, and only one species S. sinensis Zhao, was reported in 1991 which was considered as a member of Minor Group. The paper reports a second species of Scolecopteris, i.e.S, shanxiensis sp. nov., which differs from the above four groups in that its outer facing wall of the sporangia is thick at the base and top (2 ~ 3 layers of cells), and a little thinner ( 1~2 layers of cells) at the midlevel of the synangia. So a new group, Shanxiensis group, is set for the new species. The other characteristics of Shanxiensis group is comparable with Minor group. The new species comes from the coal balls in Coal Seam No. 7 in the upper part of Taiyuan Formation (early Early Permian) from Taiyuan, Shanxi, China. The identification of Scolecopteris shanxiensis sp. nov. :The fertile pinnule probably peeopterids, 5.5 ~ 6.0 mm in length and 2.0 ~ 2.2 mm in width. The lateral extensions of the lamina of the pinnule bend abaxially and above the synangia. The synangia arrange along the sides of the midrib of the pinnnle and there are about 10 synangia in each row. The synangium is elliptical in longitudinal section and radial in cross section, 0.7 ~ 0.8 mm in height and 0.6 ~ 0.7 mm in diameter. Each synangium has 5-7 (mostly 6) fusiform sporangia fused at the base and attached to the top of the synangial pedicel. The outer facing wall of the sporangia consists of 2~3 layers of cells at the base and becomes thinner at the midlevel (1~2 layers of cells), and at the top of the synangia the wall become thicker again. The cells of the outer facing wall of the sporangia are elongate in the longitudinal sections. The lateral and inner facing walls of the sporangia are one cell thick. The synangial pedicel is small. Spores in situ are small, generally 11~14 µm in diameter, spherical or rounded-triangular, trilete and smooth-walled.  相似文献   

7.
Material described by Graham as Cyathotrachus bulbaceus is believed to represent a new genus that is a common constituent of Upper Pennsylvanian coal balls. The sessile synangia of Acaulangium gen. n. are borne in a row on either side of the pinnule midrib and are composed of four to six short, tapering, laterally appressed sporangia. The sporangia have extended tips which curve over the inside of the synangium distally and delimit a small open area inside the synangium. The outer facing walls of the sporangia are two to three cells thick throughout while the inner facing walls are uniseriate. During dehiscence the sporangia separate laterally and spore release results from the rupture of a row of elongate cells along the inner sporangium midline. Among species of Scolecopteris the new genus resembles S. illinoensis and S. minor var. parvifolia but differs in its sessile synangial attachment. The additional parenchyma present between sporangial cavities in the synangia of Acaulangium, and the tendency toward bilateral symmetry suggests an early stage in the evolution of a bivalve synangium such as is present in Marattia.  相似文献   

8.
Remains of the fossil Marattiales are very rare in Lower Pennsylvanian sediments. The present report describes a new species of the fertile fern foliage Scolecopteris from the Lewis Creek, Kentucky locality (Lower or lower Middle Pennsylvanian). Scolecopteris conicaulis n. sp. has radial synangia composed of a ring of 4–7 elongate, exannulate sporangia. Most features of the synangia of S. conicaulis were previously hypothesized to be primitive in Scolecopteris based on geologically younger species. Supposed primitive characters include the large synangium pedicel with fiber core, an outer-facing sporangial wall lacking differentiation or zonation, and large spores. The anatomy of the sporangium walls, pinnule morphology, and general spore type support an association with the Minor group of Scolecopteris. The new species is similar in several important features to Scolecopteris (Cyathotrachus) altus, the only other anatomically preserved fertile marattialean known from this early time, and indicates a considerably earlier origin for fertile foliage of this type.  相似文献   

9.
A new fossil genus and combination of gigantopterides is reported. The specimen was collected from the Late Paleozoic "Longtan Formation” of Jiangle county, Fujian Province of China. It was originally determined to the genus Gigantonoclea and named as G. cardiophylla Zhu et Geng by one of the present authors and his colleague some times ago. In view of its venation being trinervious and that the incompletely duplicated net-like veins are close to those of gigantopterides and the leaf bears sori on its back. Upon reconsideration it was renamed by the authors as Trinerviopteris cardiophyUa (Zhu et Geng) Zhu gen. et comb. nov. At the same time. the authors have confirmed that it is a kind of true fern. In association with the new taxon there are Sphenophyllum emarginatum, Bowmanites lascus, Lobatannularia lingulata, Chansitheca pcdaeosilvana, Ch. cf. kidstonii, Pecopteris anderssonii, P. echinata, P. taiyuanensis, P. unita, Danaeites mirabilis, Fascipteris densata, Cladophlebis permica, Compsopteris contracta, Gigantonoclea chingii, G. fukienensis, G. sp., G. sp., Gigantopteris cordata, G. nicotianaefolia, Taenioteris serrulata, T. szei, T. tingii, Radicites sp. 1, R. sp. 2 etc. The present flora is more simplified than the others which discovered from different areas in the same geological time. Based on the grouping of these fossil plants, the geological era of the present flora must be late Early Permian to early Late Permian. Moreover it is emphasized that the gigantopterides is only but an artificial compound taxon not only including seed ferns but also true ferns and others.  相似文献   

10.
11.
Ovule-bearing leaves from the Paleozoic of North America assigned to Spermopteris and Phasmatocycas have been interpreted as primitive cycad megasporophylls. According to this hypothesis, Cycas megasporophylls were derived from a Spermopteris-like ancestor via Phasmatocycas and various other taeniopterid forms. This putative transformation entailed the phyletic shift of ovule attachment from the abaxial lamina surface of Spermopteris to the leaf midrib in Phasmatocyas. However, reexamination of the original Spermopteris specimens from the Lawrence Shale of Kansas has shown that the ovules are attached to the leaf midrib. Therefore, Spermopteris and Phasmatocyas differ only in a few details of lamina morphology. The apical cleft of the ovules of both forms is interpreted as an original feature rather than a preservational artifact; however, the abaxial flange is probably a result of compression of a terete midrib. Spermopteris is typified by sterile specimens of Taeniopteris coriacea from Europe, which are of uncertain affinity to the fertile leaves. Therefore, we propose that the ovule-bearing leaves now known as Spermopteris coriacea be named as a new species of Phasmatocycas (Phasmatocycas bridwellii sp. nov.). The new concept of Phasmatocyas is less cycad-like than previously thought, and the phylogenetic position of the genus is unclear.  相似文献   

12.
13.
Abstract: Morphology, development and anatomy of the male cones of Zamia amblyphyllidia are studied here to amass additional information to develop a more convincing concept of the evolution of seed plants. The male sporangiophores of the cycads are usually regarded as simple sporangiophores with synangia on the abaxial side. Our developmental study of the male sporangiophores of Zamia amblyphyllidia, by scanning and light microscopy, suggests that the sporangiophores are pinnate, with synangia on reduced leaflets. This indicates that a significant difference between female and male sporangiophores in cycads, as previously stated, does not exist. Comparisons of male sporangiophores of cycads with those of conifers show that they are not homologous. Rather, the synangia of the cycads may better be homologised with the radial synangia groups in some pteridosperm taxa. Although several authors assume that the cycad precursor displayed entire, fertile and sterile leaves, our interpretations of the male sporangiophores indicate that cycads originated from a pinnate pteridospermous ancestor with radial synangia groups. These hypotheses may point to the Medullosaceae, although this remains to be substantiated.  相似文献   

14.
Paleozoic pollen organs exhibit numerous morphological forms that have been arranged in categories based on their probable organization. Progymnosperm ancestors are characterized by three dimensional branching systems bearing pairs of terminal sporangia. Early Mississippian examples of seed fern fertile branches appear little modified from the progymnosperms. These pteridosperm microsporangia are nonsynangiate and thin walled with longitudinal dehiscence. By Upper Mississippian time all forms show sporangial clustering into large or small groups, with several taxa exhibiting radially symmetrical synangia. In the Lower Pennsylvanian all pollen organs are synangiate and appear to consist of a uniseriate ring of sporangia that either surround a central hollow, or are bilaterally flattened. Sporangial dehiscence in all forms is longitudinal and toward the center of the synangium. In bilateral synangia with no central hollow, the sporangia either separate laterally or effective dehiscence areas are restricted to the free apical portions of the sporangia. Callistophytacean synangia resemble the lyginopterid type, but are abaxial on laminar foliage. This family is thought to have evolved from the lyginopterids during the Early Pennsylvanian. Middle Pennsylvanian medullosan pollen organs are all radial and may be solitary, aggregated into groups, or fused into a large compound synangium. Several pollen organ types are reinterpreted, and the possible evolutionary relationships among the various Paleozoic pollen organ forms are discussed based on synangial organization, patterns of frond branching, and pollen or prepollen morphology.  相似文献   

15.
A fossil plant discovery from the Price (Pocono) Formation of southeastern West Virginia provides new information on the poorly known compression floras of the Lower Mississippian of North America. The new plant described herein consists of long tapering bipinnate fronds with imbricate basal pinnae, planate apical pinnae, and unlobed, elliptical to obovate pinnules with open dichotomous venation. Veins concentrated in the medial region of the pinnule curve toward the lateral margin, suggestive of an early stage in the evolution of a midrib. Pinnules exhibit a distinctly revolute or otherwise reinforced margin. The exceptional length of some fronds (over 1m) and pinnule size (some over 3cm by 2cm) strongly contrast with the generally diffusely branched fronds and small or highly dissected pinnule morphology that typify Early Mississippian leaf taxa. A new generic assignment, Charbeckia macrophylla, is thereby justified. The rigid appearance of the tapering rachis, the imbricate pinnae that appear to have resisted compression, and the reinforced pinnule margins imply thick evergreen leaves, perhaps adapted for drought tolerance. A possible Calamopityalean affinity is indicated by the size of the fronds and the stout petioles, which fall within the expected size range of the Kalymma-type petiole bases described from the nearby New Albany Shale of Tournaisian age.  相似文献   

16.
More than 50 specimens of permineralized fertile pinnules with abaxially borne sporangia have been discovered in calcareous marine nodules from the Upper Cretaceous (Coniacian) Comox Formation from the Eden Main localities on Vancouver Island, British Columbia, Canada. Isolated pinnules 1.6–3.0 mm wide × 1.6–2.8 mm long are lobed and abaxially enrolled to form irregular globose structures. Pyriform sporangia 216–300 μm wide × 360–468 μm long occur in two rows on the abaxial surface of pinnule lobes. Sporangia have an apical annulus of 15–18 cells. Spores are tetrahedral and trilete, 33–42 μm in diameter, with straight to concave interradial sides, laesurae extending nearly to the equator, and a psilate exine. Spores are assignable to the sporae dispersae genus Deltoidospora. Fertile pinnules are compared to fossils of Anemia poolensis and two previously described species of Paralygodium, and show closest similarities to P. vancouverensis from the Eocene of British Columbia. The Cretaceous Eden Main specimens differ in number of pinnule lobes and their morphology and are described as a new taxon: P. meckertii sp. nov. This discovery extends the Cretaceous geographic range of Paralygodium from Japan to North America and adds to our knowledge of the diversity of extinct schizaeaceous ferns.  相似文献   

17.
Sydneia manleyi gen. et sp. nov. is based on part of a fertile frond from the upper Westphalian D of the Sydney Coalfield, Nova Scotia, Canada. It has small synangia composed of laterally fused sporangia that are elongate and with a circular cross-section. The sporangia yielded variably sized monolete and trilete spores with laevigate and microspinate ornamentation; intermediate forms were also observed. The spores can be correlated with the sporae dispersae species Latosporites minutus , Punctatosporites oculus and Laevigatosporites minimus . Size distribution of the spores is variable and highly skewed, suggesting heterogeneity of the spores within the sporangium. Spore ultrastructure indicates that the fossil is part of a fern, and the morphology of the spores and synangia indicate marattialean affinities.  © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society , 2003, 142 , 199–212.  相似文献   

18.
This paper has described a new genus and species on the basis of two pieces of fertile fern pinna specimens found from Tanshanwan Coal-bearing Formation in Dawangdian, Yangxin district of eastern Hubei Province. One of the specimens described here is an upper part of a pinna which is belt- shaped, entire, about 7 cm in length and 1 cm in breadth, acuminate, tomentose. Its midrib marked with an obvious ventral furrow, rather stout, approaching lmm in breadth. Lateral veins barely distinguishable, bifurcating once, about 12 veins per 1 cm margin of pinna. Spoangium finger-shaped, slightly curved, obtuse, without annulus, about 1.2 mm in length and 0.4 mm in diameter, rough. Synangium ovate or elliptic, 0.8 mm in diameter and 12 mm in length, consists of 5–6 sporangia, bearing 5–6 longitudinal ridges and furrows similar to those of such genera as Acitheca, Asterotheca, Ptychocarpus etc., but not free on upper part. Synangia of this new genus insert in a placenta which was developed by the end of each lateral vein spreading beyond the pinna margin. Synangium slightly contiguous with each other. Judging by the nature of the synangium this new genus probably belongs to the order Marattiales, quite possibly an indirect progeny from the genus Ilfeldia which has a common ancester with the genus Scolecopteris in phylogeny. According to the feature of the fossil plant society, the authors regard the geological age of the Tanshanwan Coalbearing Formation, in which Fimbriotheca tomentosa was found, as Early Upper Permian.  相似文献   

19.
A survey of xeniid octocorals was carried out in the waters off Southwestern Thailand in September, 2007. Microscopic investigation of the colonies revealed that three specimens belonged to the genus Ovabunda. Gross morphological examination is presented here accompanied by scanning electron micrographs of the sclerites. Molecular phylogenetic analysis showed identical genotypes at mtMutS, COI, and 28S rDNA for all three specimens and supports their generic assignment. Colony size and shape, sclerite size, and pinnule arrangement differ from nominal species of Ovabunda and thus a new species, O. andamanensis is introduced here. This work also presents a new eastern geographical record for the genus Ovabunda.  相似文献   

20.
报道了广西蕨类植物一新记录科——光叶藤蕨科.该科植物以茎圆柱形攀缘;叶二型,通常为奇数羽状;侧生羽片以关节着生于叶轴;不育叶羽片边缘具软骨质硬齿,羽片基部上侧具一腺体;叶脉细密,中肋两侧各具1行窄长网眼,向外伸出分离小脉;能育叶线形,孢子囊群密被羽片下面,无隔丝而与其他蕨类物种相区分.目前该科在广西仅记录光叶藤蕨1种,...  相似文献   

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