云南曲靖下泥盆统西山村组四营鱼属(Siyingia)一新种(英文)

主要采用形态学与比较解剖学的方法,对采自云南曲靖地区下泥盆统西山村组中的1件盔甲鱼类标本进行了详细的形态学研究,建立了多鳃鱼类四营鱼属1新种:宽棘四营鱼(Siyingia perlatuspinosa sp.nov.),并据此修订了四营鱼属的特征。在此基础上,应用分支系统学对多鳃鱼类属一级的系统发育关系进行了重新分析与探讨,确定了四营鱼在多鳃鱼类中的系统发育位置。系统发育分析结果显示,四营鱼(Siyingia)与多鳃鱼(Polybranchiaspis)亲缘关系最近,二者形成了一个单系类群,与宽甲鱼(Laxaspis)+坝鱼(Damaspis)组成的单系类群互为姊妹群。宽棘四营鱼的发现不仅拓宽了四营鱼在华南的时空分布范围,而且丰富了多鳃鱼类的多样性,并为多鳃鱼类的深入研究提供了可靠的化石新证据。     

Emsian (Lower Devonian) conodonts from the Daliantang Formation at Daliantang,southeastern Yunnan,China

The lower/upper Emsian boundary witnessed prominent diversification of biostratigraphically important genera Polygnathus Hinde, Caudicriodus Bultynck, and Latericriodus Müller. In contrast, conodonts previously reported around this boundary from the South China Block were characterized by relatively low species or subspecies diversity, and only a few widely distributed and extensively studied zone-defining taxa were recorded. In this paper, conodonts from the Daliantang Formation at the Daliantang section (Guangnan, southeastern Yunnan), one of the representative sections of the transitional facies between the benthic Xiangzhou facies and the pelagic Nandan facies, are investigated. The conodont fauna shows a remarkably high species or subspecies diversity, with fourteen taxa that are assignable to the notoperbonus Zone and inversus Zone. Five polygnathid species are described: P. gronbergi Klapper and Jonson, P. inversus Klapper and Jonson, Polygnathus sp. B, P. luciae Martínez-Pérez and Valenzuela-Ríos, and P. mashkovae Bardashev. The latter two are reported for the first time from the South China Block. Additionally, three icriodontid taxa are also described, of which L. guangnanensis n. sp. is characterized by distinctly chevron-shaped transverse rows in the anterior part and a well-developed process branching off to the outer side. The new conodont record increases our understanding of the diversification and faunal composition around the lower/upper Emsian boundary in the South China Block. It contributes to the regional and inter-regional biostratigraphical correlation between shallower- and deeper-water facies and also furnishes important South China material for future discussion and deliberation on the position of the lower/upper Emsian boundary.     

Morphology and wall ultrastructure of the spores of the Lower Devonian plant Oocampsa catheta Andrews et al., 1975

The enigmatic Lower Devonian plant Oocampsa catheta Andrews et al. (Can. J. Bot. 53 (1975) 1719) is considered intermediate between the trimerophytes and progymnosperms. In order to shed light on its evolutionary relationships, the morphology and ultrastructure of its sporangium and spores were analysed using light, scanning electron and transmission electron microscopy. In addition, dispersed spores (Grandispora douglastownense McGregor (Palaeontographica B 142 (1973) 1) and Grandispora ?macrotuberculata (Trudy VNIGNI 37 (1963) 18) McGregor (Palaeontographica B 142 (1973) 1), considered to possibly represent forms derived from O. catheta, were also examined. It is concluded that G. douglastownense and G. ?macrotuberculata are probably end members of the same spore complex and most likely are dispersed spores produced by O. catheta. Oocampsa catheta spores are bilayered. An inner body has an innermost part consisting of continuous, parallel-stacked, laminae and an outermost part consisting of more erratic, anastomosing, laminae. The inner body is surrounded by an homogeneous outer layer that is extended at the equator forming a pseudozona, and is folded on the proximal surface forming the trilete mark and on the distal surface forming spinose ornament. The spores are partially camerate. On the inside of the sporangium wall there is a layer probably representing the residue left following degeneration of a (probably secretory) tapetum. Spore morphology, gross structure and wall ultrastructure are compared to that of extant and fossil plant groups, and it is concluded that the spores of O. catheta are highly distinctive and do not conform closely to any plant group, although they show most in common with the spores of the progymnosperms.     

Gumuia gyzzata A New Plant from the Lower Devonian of Yunnan,China

A new genus and species, Gumuia zyzzata is found in the Posonchong Formation of the Lower Devonian (Siegenian) from Wenshan district of Yunnan, China. It has both lateral and terminal sporangia. Successive sporangia develop on alternate sides of short axes near the hases of preceding sporangia, producing a zigzag fertile organization. The author supposes that it is a sympodium Opposite sporangia are suppositionally referred to the result from condensation of the axis between alternate sporangia. The new plant is tentatively referred to a putative zosterophyll.     

A new microphyllous plant from the Lower Devonian of Yunnan Province, China

Sterile and fertile shoots of a microphyllous vascular plant are described from the Lower Devonian Posongchong Formation (? upper Siegenian), Yunnan Province, southern China and placed in the new taxon Halleophyton zhichangense gen. et sp. nov. The sterile axes are characterized by conspicuous, contiguous swollen rhomboidal to hexagonal leaf bases and relatively broad spatulate laminae. The relief of the leaf bases is not so pronounced in the fertile areas, which bear numerous cauline sporangia with two equal valves. In vegetative characters the new fossils, although smaller and more fragmentary, resemble Drepanophycus gaspianus but in the absence of information on the fertile parts of the latter and because of the controversy surrounding the concept of the genus Drepanophycus, we decided to erect a new genus. Its relationship to the lycophytes sensu stricto is equivocal as exact details of the relationship of sporangium with leaf and sporangium vascularization remain unknown.     

Brachiopods from the family Ambocoeliidae George (Order Spiriferida) from the Emsian (Lower Devonian) of northeastern Russia

Brachiopods from the family Ambocoeliidae George from the Emsian (Lower Devonian) of northeastern Russia are described: Bisinocoelia despecta sp. nov.; Yakutospirifer gen. nov. with the type species Y. krivensis sp. nov.; Micospirifer gen. nov. with the type species M. simplex sp. nov.; Kolymospirifer gen. nov. with the type species K. optatus sp. nov. (subfamily Ambocoeliinae); Datnospirifer gen. nov. with the type species D. alius sp. nov.; Khalimospirifer gen. nov. with the type species Kh. microscopicus sp. nov.; Gerospirifer gen. nov. with the type species G. normalis sp. nov., and G. gerensis sp. nov.; Dogdospirifer gen. nov. with the type species D. yolkini sp. nov. (subfamily Rhynchospiriferinae).     

云南早泥盆世一流线型盔甲鱼及其分类学与古生态学意义(英文)

记述了云南昭通早泥盆世布拉格期坡松冲组华南鱼目一新属、新种——剑裂甲鱼(Rhegmaspis xiphoidea gen.et sp.nov.)。新属的主要特征是:具有鱼雷形头甲,细长吻突,眶孔位于头甲腹侧位,鳃穴向头甲腹面弯曲,角、内角和腹环丢失。鉴于以上特征,新属被归到了包括鸭吻鱼和乌蒙山鱼在内的鸭吻鱼科。根据新材料提供的信息,修订了鸭吻鱼科,包括鸭吻鱼和乌蒙山鱼的鳃穴、腹环、角、内角等特征。裂甲鱼属是该地区发现的第一个具有流线形体型的盔甲鱼类,指示了该地区一些盔甲鱼类可能开始了一种营上底栖的生活方式,具有更加主动的取食行为。新属的发现不仅丰富了该地区华南鱼目的多样性,而且提供了盔甲鱼类在早泥盆世布拉格期通过占据新的生态位而发生的最后一次辐射演化的证据。     

Some observations on Zosterophyllutn australianum Lang & Gookson from the Lower Devonian of Yunnan, China

SHOU-GANG, H., 1992. Some observations on Zosterophyllutn australianum Lang & Cookson from the Lower Devonian of Yunnan, China. Recent collections of Zosterophyllum australianum have been made from the Xujiachong Formation which outcrops near Xujiachong village in the Qujing district of Yunnan province. The unit is a non-marine facies of the type section of the Lower Devonian of China. Sediments containing the fossil material are probably Siegenian-Emsian in age. Details of the morphology of fertile spike of Z. australianum are recorded. The spikes bear short-stalked, rather large, transversely elliptical sporangia, each with a wide, thickened, distal border. Sporangia are borne close together in a dextrorse helix, and usually in four or five longitudinal rows. Morphological variation of in-situ spores is also described. Comparison of the new specimens with others of reported Z. australianum has led to some nomenclatural changes.     

Lower Middle Devonian,Eifelian, crinoids from central Guangxi,South China

The extensive Devonian marine deposits of South China have yielded few articulated crinoid cups or theca. Two Eifelian specimens, from the Gupa Member, are the first ones reported from the Yingtang Formation, Eifelian, from the Ma’anshan section, Guangxi, South China. The new taxon Guangxicrinus xiangzhouensis n. gen. n. sp. is the first report of a marsupiocrinid in China, extending the paleogeographic range of the family into the Paleotethys and the stratigraphic range of the family upward from the upper Silurian into the lower Middle Devonian, Eifelian. The occurrence of Halocrinites sp. is the third occurrence of a cupressocrinitid in China and extends the paleogeographic range from Yunnan to Guangxi.     

Huia Recurvata --- A New Plant from Lower Devonian of Southeastern Yunnan China,

A new genus and species Hula recurvata is described from the Posong-chong Formation (Siegenian) of Lower Devonian in Wenshan district, Yunnan, China.This plant possesses pseudomonopodial and dichotomous axes with terminal spikes andit sometimes has single sporangia below the branching point within the fertile regions.Sporangia with stalks are ovate, adaxially recurved and downwards and spirally arrangedon the axis of the spike. Protostele is centrarch. The characteristics stated above showthe new plant has close affinity to Taeniocrada decheniana, but it differes from the members of any other rhyniophytes as well as zosterophyllophytes. A new family——Taeniocradaceae can be established and is provisionally assigned to Rhyniophytina. Evolutionary line of early land-plants, from Rhyniaceae to Taeniocradaceae and then to Bari-nophytaceae is discussed in this paper.     

A new species of vascular plants from the Xujiachong Formation (Lower Devonian) of Yunnan Province, China

A new species of early land vascular plants, Huia gracilis, is described from the Lower Devonian (Pragian-early Emsian) Xujiachong Formation, Qujing district, Yunnan Province, southwestern China. The plant possesses K- or H-type branching in the rhizome and a dichotomously branched erect system. An axillary tubercle is sometimes present at the branching position. Fertile axes terminate in loose spikes comprising terminal and lateral sporangia arranged helically. Sporangia with long stalks are ovate or elongate-ovate and reflex adaxially. The sporangium dehisces longitudinally in the radial plane of the fertile axis into two parts. The xylem is probably centrarch. Tracheids of G-type are characterised by annular secondary thickenings, between which is a sheet with irregular simple perforations. There may be some 'pores' in the enclosing wall of the perforation. H. gracilis differs from the type species H. recurvata mainly in the branching pattern, more slender morphology of the stem, sporangium and stalk. It is suggested that Huia may have originated from the primitive Cooksonia-like plants.     

A New Lower Devonian Genus from Yunnan,with Notes on the Origgin of Leaf

A new genus and species, Eophyllophyton bellum, is described from the Posongchong Formation (Siegenian) of the Lower Devonian in Wenshan cfistrict, Yunnan, China This plant bears lateral branching laminate structures interpreted as leaves, which are believed to derive from lateral axial branching systems In addition similarly organised sporophylls are considered homologous to these leaves. In the possession of these vegetative leaves and sporophylls Eophyllophyton, is significantly more advanced than any other Siegenian taxon.     

The northern most Emsian crinoids known, a Devonian fauna from the Chuluun Formation, Shine Jinst area, Southern Mongolia

The most northerly known Emsian crinoids were located at approximately 45° to 50° N latitude. They are the first Devonian crinoid cups discovered in Mongolia. Specimens are reported from excellent exposures of the informally designated crinoidal beds in the upper part of the stratotype section of the Chuluun Formation, between N44° 22.119', E99° 27.130' and N44° 22.201', E99° 26.906', near the Tsakhir Well, in the foothills south of Tsagaan Khaalga Mountain, Shine Jinst area, southern Mongolia. All specimens are crushed, altered by low-grade metamorphism, and ossicles flake as they weather. Five genera are present including a new genus of the Periechocrinidae, two indeterminant camerates, an undesignated new species of Cyathocrinites, and one indeterminant crinoid. These genera agree with a middle Emsian age previously assigned to the upper part of the Chuluun Formation on the basis of brachiopods and conodonts. They show affinity to European and North American Emsian faunas.     

Lower Devonian Polyplacophora from New South Wales, Australia

Silicified polyplacophorans are common in the Lower Devonian Garra Formation in New South Wales. Four taxa occur within the lower 237 m of the formation at 14 horizons associated with an abundant and diverse fauna. Chelodes calceoloides Etheridge ranges through the section. New taxa are Chelodes cordatus sp. nov., Acutichiton depressolatus sp. nov., and Jugochiton patulus gen. and sp. nov. A single plate of an indeterminate genus occurs in the lower portion of the Camelford Limestone.     

The Pragian-Emsian conodont successions of the Barrandian area: search of an alternative to the GSSP polygnathid-based correlation concept

Six Pragian-Emsian boundary sections in the Barrandian area, western of Prague, provided evidence of well detectable entries of Latericriodus fauna probably at the earliest Emsian beds (particularly Latericriodus bilatericrescens gracilis Bultynck). The chance to find icriodontid conodonts increases with latest part of Praha Fm., which is apparently of Emsian age, whereas polygnathids are sparsely preserved to absent. The high icriodontid/polygnathid ratio links together all these Barrandian sections, although their open-sea depositional environments range widely from deep troughs with rapid calciturbidite accumulation (Pod Barrandovem section) to relatively starving slope environments on elevations (Na Po?árech sections). The reports on polygnathid occurrences around the Pragian-Emsian boundary beds of the Barrandian area are much biased by poor reproducibility of the results (the conodonts cannot be found again) as well as by different levels where they were randomly found and/or by major taxonomic problems with the “kitabicus” and “dehiscens” definitions and their stratigraphic use. Apart from the GSSP in the Zinzilban Gorge (Uzbekistan) and its “kitabicus” boundary, the newly introduced “gracilis” biostratigraphic-marker concept preserves the major volume of the Pragian and respects also approximately the base of the traditional Emsian. These “gracilis” entries are clustered around the dark-colored “graptolite-bearing interval” beds, which largely form a prominent lithological marker within the latest, light gray-colored Dvorce-Prokop Limestone of the Barrandian area. This “gracilis” biostratigraphic marker has a promising correlation potential relative to Spanish and Moroccan sections.     

Hsüa deflexa sp. nov. from the Xujiachong Formation (Lower Devonian) of eastern Yunnan, China

A new vascular plant, Hsüa deflexa sp. nov., is documented from the Lower Devonian ((upper) Pragian-lower Emsian) Xujiachong Formation, near Xujiachong village, Qujing District, eastern Yunnan, South China. In three dimensions, the branching system comprises a robust creeping main axis and comparatively slender erect lateral axes inserted oppositely or alternately. The lateral axes depart at right angles from the main axis. Towards the apex, the main axis is perhaps erect with the lateral axes attached at smaller angles. The lateral axes dichotomize equally one to three times in different planes and decrease in diameter and length acropetally. They bear sparse and irregular tiny spines. Apices of a pair of distal lateral axes curve in opposite directions and each terminates in a rounded to reniform sporangium. The sporangium dehisces into two equal valves along an indistinct convex marginal thickening. The xylem is possibly centrarch. This plant fits Hsüa in branching pattern, sporangial characters and xylem maturation. Hsüa deflexa sp. nov. differs mainly from the type species H.  robusta in the presence of axial spines, perpendicular extension of lateral axes from the main axis and curving of distal lateral axes. Based on the possibly centrarch xylem and terminal sporangium, this plant relates to the rhyniophytes ( sensu Banks, 1968). In view of the equal sporangial valves with marginal thickenings it resembles the zosterophyllophytes ( sensu Banks, 1968). Hsüa is now treated as incertae sedis .  © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society, 2003, 142 , 255−271.     

New insights into the base of the Emsian (Lower Devonian) in South China

Traditionally, the lower boundary of the Emsian (Lower Devonian) has been defined as the base of the dehiscens Zone marked by the first entry of the conodont Polygnathus dehiscens. However, following taxonomic revision of P. dehiscens, the current practice is to use the first appearance of P. kitabicus to define the base of the Emsian. As a result, specimens previously identified as P. dehiscens from South China need to be thoroughly reviewed. Careful examination of the oral and aboral features of the platform reveal that most specimens previously described as P. dehiscens from nine sections in Guangxi and Yunnan actually refer to P. excavatus excavatus or P. excavatus ssp. 114. In the South China Block, widespread and massive deposition of Devonian carbonates began during the time of the excavatus Zone, whereas the kitabicus Zone is probably located in the underlying strata, which mainly comprise marine siliciclastic rocks. Thus, the precise level of the lower boundary of the Emsian in South China is still unknown.     

A reconsideration of Dimeripteris cornuta SCHWEITZER and CAI, a diminutive fossil plant from the Middle Devonian of Yunnan, China

Small plant fragments previously attributed to Dimeripteris cornuta SCHWEITZER and CAI and new specimens are described from the Middle Devonian (Givetian) Xichong Formation of Wuding, Yunnan Province, southwest China. A predominantly trifurcate branching pattern is recognized in lower orders of branching. Erect fusiform sporangia are borne in pairs terminally on a short pedicel on up to three times dichotomously-branching fertile unit. The beaked tips of the paired sporangia point outwards. This plant is distinguished from known plants by the trifurcate branching pattern and sporangia morphology, but is of problematic affinity. The plant is named Tauritheca cornuta (SCHWEITZER and CAI) WANG and BERRY nov. gen. and nov. comb.     

Permanent dyads in sporangia and spore masses from the Lower Devonian of the Welsh Borderland

Dyads, interpreted as cryptospore permanent dyads, are reported from sporangia and spore masses recovered from fluviatile deposits of Lochkovian (Early Devonian) age from the Welsh Borderland. The morphology, anatomy and ultrastructure of the specimens have been analysed using LM, SEM and TEM. Two specimens consist of a single sporangium terminating an axis: one is cup-shaped and attached to an unbranched axis and named Culullitheca richardsonii gen. et sp. nov., the other comprises an isotomously branching axis with one sporangium preserved and is named Fusitheca fanningiae gen. et sp. nov. Two specimens show dyads adhering to cuticular fragments presumably derived from sporangia. In one the cuticle is of irregular shape, in the other it is elliptical. The final specimen comprises an elongate spore mass. In all cases ultrastructural analysis reveals that the spore walls are essentially homogeneous. Our findings suggest that cryptospore permanent dyads were produced by rhyniophytoid plants of small stature. The affinities of these plants remain conjectural, as is the relationship of the cryptospore permanent dyads with other sporomorph morphotypes (cryptospores and trilete spores). However, the production of dyads by a plant with a bifurcating sporophytic axis is evidence against affinity with extant bryophytes. The mode of formation, adaptive significance, affinities, phylogenetic relationships and stratigraphical history (including demise) of cryptospore permanent dyads is discussed.     

Notes on a fertile rhyniophytoid from the Lower Devonian of Guangxi,southwestern China

A fertile rhyniophytoid is discovered from the Lower Devonian of Guangxi, southwestern China, which is characterised by small size, dichotomous branchings and terminal sporangia. This plant is similar to the genus Aberlemnia Gonez et Gerrienne and also, is comparable to some mesofossil morphotypes of early land plants from the Early Devonian (Lochkovian) Old Red Sandstone floras. This study adds new data to the generally zosterophyll-dominated Early Devonian floras of South China and sheds some lights on the palaeophytogeography of rhyniophytoids.