摘要:

Four different types of structures on fossil arthropods are shown to have been grouped under the term ‘genal caeca’. These are distinguished and the most conspicuous (i.e. the fine radiating cephalic ridges of trilobites that anastomose repeatedly before joining a major ridge in the border) are interpreted as the external representation of auxiliary respiratory systems at least in some Cambrian genera. A number of possible functions are considered for these ridges and none but respiration is found to be feasible. Supportive evidence for the hypothesis outlined is drawn from consideration of the paradigm for a dorsal respiratory system and from a comparison with living crustacea.

ISSN:0311-5518    

DOI:10.1080/03115517808527783

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Palaeolimnadiopsis bassisp. nov. is described from the mid-Triassic Hawkesbury Sandstone of the Sydney Basin, New South Wales. It is distinguished from other species of the genus by its paired growth lines, moderately large size, nonterminal umbo, and small larval valve.Macrolimnadiopsis, Pteriograpta, andLimnadia (Falsisca)are considered to be synonymous withPalaeolimnadiopsis, andBelgolimnadiopsiswithEuestheria.

ISSN:0311-5518    

DOI:10.1080/03115517808527784

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

A diverse assemblage of organic microfossils is preserved within stromatolitic cherts from 10 localities in the approximately 1500 m.y. old Balbirini Dolomite. The assemblage is dominated by coccoid blue-green algae referable to the Entophysalidaceae and the Chroococcaceae. There are a few oscillatoriacean and dermocarpacean or pleurocapsacean cyanophytes, and sporangia-like spheroids of uncertain affinities are abundant. A total of 14 genera including at least 25 species have been identified; however, at any particular locality, the species diversity is relatively low.

ISSN:0311-5518    

DOI:10.1080/03115517808527785

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

ISSN:0311-5518    

DOI:10.1080/03115517808527786

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

The Maslin Bay flora of South Australia is of lower Middle Eocene age and contains diverse, well preserved angiosperm assemblages. It has yielded 2700 specimens belonging to approximately 200 leaf taxa.

ISSN:0311-5518    

DOI:10.1080/03115517808527787

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Six biostratigraphically distinct faunas based largely on trilobites and graptolites are defined from the Lower to Middle Ordovician limestone, sandstone and shale sequence of the Canning Basin. They range in age from the Tremadoc (fauna 1), through the Arenig (faunas 2, 3) to the Llanvirn (faunas 4–6).

ISSN:0311-5518    

DOI:10.1080/03115517808527788

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor