Showing papers by "Margaret E. Collinson published in 2014"
TL;DR: In this paper, nine fossil wood specimens are described from the Miocene (early to mid-Burdigalian) part of the Cucaracha Formation of Panama, Central America, and they show tile cells characteristic of many clades of the diverse and widespread family Malvaceae sensu APG III.
24 citations
TL;DR: A new interpretation of the Palaeocene to Eocene strata of SE Nigeria has been developed based on field facies analysis and borehole data from the area as discussed by the authors, where the area is considered to have been a tidally-dominated shelf setting which underwent a series of changes in sea level during the deposition of the Imo Shale.
22 citations
01 Sep 2014
15 citations
01 May 2014
TL;DR: In this paper, two hundred and sixty-six specimens of cardioceratid ammonites were found in concretions from the Tenants' Cliff Member of the Lower Calcareous Grit Formation (Upper Oxfordian, Upper Jurassic) at Tenants’ Cliff, near Scarborough, England, were analysed to determine the type of damage within the assemblage.
Abstract: Summary Two hundred and sixty-six specimens of cardioceratid ammonites found in concretions from the Tenants’ Cliff Member of the Lower Calcareous Grit Formation (Upper Oxfordian, Upper Jurassic) at Tenants’ Cliff, near Scarborough, England, were analysed to determine the type of damage within the assemblage. Forty-five specimens were severely damaged. They consist largely of just a body chamber fragment, with small pieces of fractured shell scattered through the matrix. This type of damage is characteristic of predation by sharks or marine reptiles. Fourteen, almost complete but damaged specimens showed an indent that is either subcrescentic or V-shaped. Measurements of the position of this damage showed that the V-shaped indent was present on the body chamber of these specimens anterior to the final suture. Comparisons with other specimens from different localities and time periods, as well as sedimentological evidence and modern behavioural records, suggests that such damage was caused by squids.
6 citations
TL;DR: The morphology considerably expands the concept of variation in the genus Lygodium and suggests that this life form today may represent an evolutionary phase near to the early stages of diversification of the genus.
Abstract: A colony of a fern, Lygodium hians E.Fournier (Schizaeales), studied on the southwest Pacific Island of New Caledonia, displays a growth form unusual for any member of this genus. Other living species of the genus Lygodium Sw. are characterized by twining fronds, with indefinite growth, which climb extensively on the support provided by other nearby vegetation. These fronds can arise from as early as the sporeling stage and fulfil both vegetative and reproductive functions, with spores produced in lateral sorophores in the upper parts of the fronds. By contrast, in L. hians, climbing fronds are only rarely produced and these carry terminal to subterminal sorophores. The main vegetative growth is of a low-growing (here termed ‘ground-clothing') frond-type, of definite, rather than indefinite, growth and of unusual dichotomous blade structure. This life form has survived, in this rare and little known remote species, under conditions of considerable ecological, as well as geographic, isolation in t...
3 citations