Transactions of the Royal Society of Edinburgh最新文献_第3页

On the Carboniferous shark Tristychius arcuatus Agassiz from Scotland 苏格兰石炭纪鲨鱼Tristychius arcuatus Agassiz

Transactions of the Royal Society of Edinburgh Pub Date : 1978-09-11 DOI: 10.1017/S0080456800012898

J. R. F. Dick

{"title":"On the Carboniferous shark Tristychius arcuatus Agassiz from Scotland","authors":"J. R. F. Dick","doi":"10.1017/S0080456800012898","DOIUrl":"https://doi.org/10.1017/S0080456800012898","url":null,"abstract":"Synopsis Skeletal remains of Tristychius arcuatus commonly occur in ironstone nodules from the Scottish Upper and Lower Oil Shale Groups. This material is clearly distinguishable from the small shark from Glencartholm described by Traquair, Woodward and Moy-Thomas under this name. Study of the latter shows that its finspines are distinctly different from the holotype of T. arcuatus and, therefore, it has been renamed. Tristychius arcuatus sensu stricto is a medium-sized hybodont shark with a short gape, a functionally heterocercal tail and narrow-based, tribasal pectoral fins. Its most unusual feature is a well developed opercular gill cover composed of long hyoid rays. Evidence suggests that this character was present in several Palaeozoic sharks, although it is absent in all Recent elasmobranchs. It is not clear whether it was primitively present in chondrichthyans or evolved separately in several lineages. Hybodonts and ctenacanths are recognised as separate, specialised shark radiations, neither of which can be directly ancestral to Recent sharks. Of the two, hybodonts appear to be more closely related to Recent forms, although the presence of typical hybodont finspines in Tristychius arcuatus indicates that they had diverged from ancestral euselachians before the beginning of the Carboniferous.","PeriodicalId":23232,"journal":{"name":"Transactions of the Royal Society of Edinburgh","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1978-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87999752","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 79

TRE volume 70 issue 4 Cover and Back matter TRE第70卷第4期封面和封底

Transactions of the Royal Society of Edinburgh Pub Date : 1978-01-01 DOI: 10.1017/s0080456800012886

引用次数: 0

TRE volume 70 issue 4 Cover and Front matter TRE第70卷第4期封面和封面问题

Transactions of the Royal Society of Edinburgh Pub Date : 1978-01-01 DOI: 10.1017/s0080456800012874

引用次数: 0

11.—Some Observations on the Fertile Parts of Zosterophyllum myretonianum Penhallow from the Lower Old Red Sandstone of Scotland 11.——对苏格兰下古红砂岩带状带藻(Zosterophyllum myretonianum Penhallow)可育部分的观察

Transactions of the Royal Society of Edinburgh Pub Date : 1975-01-01 DOI: 10.1017/S0080456800015209

D. Edwards

引用次数: 40

TRE volume 69 issue 11 Cover and Back matter TRE第69卷第11期封面和封底

Transactions of the Royal Society of Edinburgh Pub Date : 1975-01-01 DOI: 10.1017/S0080456800015192

引用次数: 0

12.—Further Observations on some Lower Carboniferous Seeds and Cupules 12.——对一些下石炭世种子和小丘的进一步观察

Transactions of the Royal Society of Edinburgh Pub Date : 1975-01-01 DOI: 10.1017/S0080456800015234

J. G. Long

{"title":"12.—Further Observations on some Lower Carboniferous Seeds and Cupules","authors":"J. G. Long","doi":"10.1017/S0080456800015234","DOIUrl":"https://doi.org/10.1017/S0080456800015234","url":null,"abstract":"Synopsis Twenty-eight specimens of the seed genus Dolichosperma have been examined. Fourteen are assigned to D. sexangulatum Long; these possess six or seven integumental lobes which extend apically as free tentacles equal in length to the seed body except when damaged or broken off. Fourteen other specimens are named D. pentagonum sp. nov. These are smaller and usually have five integumental lobes (less commonly six or seven). Long apical tentacles have not been seen in this species. Evidence is adduced that Anasperma burnense Long is the mature prothallial seed developed from the ovule Eurystoma trigona Long. Eurystoma angulare Long sometimes possesses five integumental lobes and the free apical lobes vary in length. Compressed megaspores macerated from cupules of Stamnostoma huttonense Long sometimes have three abortive spores in a compact group at the apex. Ovules of Eccroustosperma langtonense Long were borne in small bunches (probably pendent) on short pedicels; one specimen of this seed shows three well-developed separate abortive spores around the apex of the functional megaspore. The cupule of Calathospermum fimbriatum Barnard shows a structure suggesting that it may have evolved from a pair of cupules. Twelve to fourteen ovules were sometimes formed in the entire cupule though most of these were probably abortive. Some possible seed embryos are described and discussed, and an outline classification of seeds in the order Lagenostomales is proposed.","PeriodicalId":23232,"journal":{"name":"Transactions of the Royal Society of Edinburgh","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1975-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90701441","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 47

10.—Triradioxylon—a New Genus of Lower Carboniferous Petrified Stems and Petioles together with a Review of the Classification of Early Pterophytina 10.-下石炭世石化茎、叶柄新属&早期蕨类植物分类综述

Transactions of the Royal Society of Edinburgh Pub Date : 1975-01-01 DOI: 10.1017/S0080456800015179

P. Barnard, J. G. Long

{"title":"10.—Triradioxylon—a New Genus of Lower Carboniferous Petrified Stems and Petioles together with a Review of the Classification of Early Pterophytina","authors":"P. Barnard, J. G. Long","doi":"10.1017/S0080456800015179","DOIUrl":"https://doi.org/10.1017/S0080456800015179","url":null,"abstract":"Synopsis Triradioxylon gen. nov. is erected for petrified stems and petioles in which the primary xylem has a triradiate form and possesses protoxylem at the ends of the arms and in the central region. Secondary xylem is dense and composed of small tracheids having multiseriate bordered pits on all walls. Rays are narrow and high. The cortex has sclerotic nests and radial bands of fibres (sparganum structure). In the type species T. primaevum sp. nov. the petioles are borne 5–6 cm apart in a phyllotactic spiral of ⅓ on a stem about 1 cm (or more) diameter. The petiole is swollen at its base (about 8 mm diameter) and very gradually tapers to about 2 mm in the rachis which has not been seen to dichotomise. The length of petiole up to the first pinna may exceed 10 cm. Pinnae arose alternately and themselves branched. The T-shaped petiolar bundle has two protoxylem groups at the end of each arm and the central protoxylem divided into three in the rachis. Two detached rachises which cannot be assigned with certainty to Triradioxylon primaevum are placed in the genus Lyginorachis and named L. whitadderensis sp. nov. In these the T-shaped vascular bundle is slightly larger than that in the rachises of T. primaevum and the ends of the transverse arms are wider and may possess three protoxylem groups. The rachises in both T.primaevum and L. whitadderensis bear alternate triarch pinna-traces but in L. whitadderensis a pair of sub-opposite monarch pinna-traces is also present. Triradioxylon is classified along with Buteoxylon in the family Buteoxylonaceae placed tentatively as incertae sedis in the Pteridosperms although showing some affinity with Aneurophyton in the Progymnospermopsida.","PeriodicalId":23232,"journal":{"name":"Transactions of the Royal Society of Edinburgh","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1975-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78565529","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 37

TRE volume 69 issue 11 Cover and Front matter TRE第69卷第11期封面和封面问题

Transactions of the Royal Society of Edinburgh Pub Date : 1975-01-01 DOI: 10.1017/S0080456800015180

引用次数: 0

TRE volume 69 issue 13 Cover and Back matter TRE第69卷第13期封面和封底

Transactions of the Royal Society of Edinburgh Pub Date : 1975-01-01 DOI: 10.1017/S0080456800015258

引用次数: 0

TRE volume 69 issue 12 Cover and Front matter TRE第69卷第12期封面和封面问题

Transactions of the Royal Society of Edinburgh Pub Date : 1975-01-01 DOI: 10.1017/S0080456800015210

引用次数: 0