Genetic and morphological analysis of multi-stemmed plants of tuart (Eucalyptus gomphocephala)

2016 ◽  
Vol 64 (8) ◽  
pp. 704 ◽  
Author(s):  
M. Byrne ◽  
A. Koenders ◽  
K. Rogerson ◽  
J. Sampson ◽  
E. J. B. van Etten
Keyword(s):  
Coastal Plain ◽  
Morphological Analysis ◽  
Growth Form ◽  
Growth Habit ◽  
Coastal Region ◽  
Morphological Differentiation ◽  
Genetic Influences ◽  
Swan Coastal Plain ◽  
Eucalyptus Gomphocephala ◽  
Stressful Environments

The tuart–banksia woodlands of the Swan Coastal Plain in Western Australia are characteristic vegetation communities of this coastal region, and Eucalyptus gomphocephala DC. (Myrtaceae; tuart) is an iconic tree of these communities. The species primarily occurs as a tall single-stemmed tree, but at the northern end of the distribution, it also occurs in a multi-stemmed form. Growth habit is frequently used as a taxonomic character in eucalypts, with many complexes having tree and mallee forms, although the genetic characterisation of growth habit in eucalypts has been limited. We investigated the genetic and morphological differentiation among populations of tree and multi-stemmed forms of tuart at the northern end of its distribution. Although the populations showed moderate levels of genetic diversity on the basis of microsatellite markers, as might be expected from populations on the periphery of the distribution, there was no evidence of genetic differentiation associated with the tree and multi-stemmed forms. Morphometric analysis showed some differences in the size of buds and fruits among the populations. Our analysis is consistent with environmentally induced variation in tuart in near-coastal populations where plants grow on poor soils and form may be affected by wind and salt exposure. This result adds to other evidence from pines and Nothofagus of environmental rather than genetic influences on growth form, particularly in stressful environments.

The zoogeographic significance of urban bushland remnants to reptiles in the Perth region, Western Australia

1994 ◽  
Vol 1 (2) ◽  
pp. 132 ◽  
Author(s):  
R. A. How ◽  
J. Dell
Keyword(s):  
Cluster Analysis ◽  
Coastal Plain ◽  
Significant Relationship ◽  
Urban Areas ◽  
Coastal Region ◽  
Swan Coastal Plain ◽  
Reptile Species ◽  
Species Area ◽  
Taxonomic Groups ◽  
Swan River

The 71 reptile species occurring in the Perth region make this area as diverse as any similar sized coastal region in Australia. Cluster analysis of the lizard assemblages of 17 bushland remnants in the region indicate that three main sub-regions can be identified; Darling Plateau and Scarp, Offshore Islands and Swan Coastal Plain. Within the Swan Coastal Plain the lizard and skink faunas of remnant bushlands on the same landform are more similar to one another than they are to those of adjacent landforms. The Swan River appears to be a distributional boundary for some species. Species-area relationships indicate a variety of responses amongst the different taxonomic groups of reptiles, with snakes being the most sensitive to loss of habitat. The isolated remnant bushlands of inner urban areas retain a variety of reptile species, but there is no significant relationship with remnant size. The implications of zoogeographic and area relationships to conservation are discussed.

Genotypic and morphological variation between Galaxiella nigrostriata (Galaxiidae) populations: implications for conservation

2015 ◽  
Vol 66 (2) ◽  
pp. 187 ◽  
Author(s):  
David M. Galeotti ◽  
Mark A. Castalanelli ◽  
David M. Groth ◽  
Clint McCullough ◽  
Mark Lund
Keyword(s):  
Morphological Variation ◽  
Coastal Plain ◽  
Coastal Wetlands ◽  
Morphological Differentiation ◽  
Early Pleistocene ◽  
Genetic Connectivity ◽  
Small Fish ◽  
Seasonally Dry ◽  
Swan Coastal Plain ◽  
South West

Galaxiella nigrostriata is a freshwater fish that is endemic to the seasonally dry coastal wetlands of south-west Western Australia and considered by the International Union for Conservation of Nature (IUCN) as lower risk–near threatened. This small fish (maximum total length<50mm) aestivates in the sediment over the long, dry Mediterranean summer and its dispersal is limited by lack of habitat connectivity. The objective of this study was to identify the historical and contemporary genetic connectivity between populations of G. nigrostriata and to assess morphological variation between these populations. Results showed that all populations were genetically divergent and no mtDNA haplotypes were shared between populations. In contrast, morphological differentiation between individual populations was weak; however, pooling populations into two broad regions (Swan coastal plain and southern coast) resulted in clear morphological differentiation between these two groups. Based on these results, we postulate G. nigrostriata distribution last expanded in the early Pleistocene ~5.1 million years ago and have since been restricted to remnant wetlands in the immediate area. Galaxiella nigrostriata populations at the northern end of their range are small and are the most vulnerable to extinction. Conservation efforts are therefore required to ensure the survival of these genetically and morphologically distinctive Swan coastal plain populations.

A revision of the textricellin spider genus Raveniella (Araneae:Araneoidea:Micropholcommatidae): exploring patterns of phylogeny and biogeography in an Australian biodiversity hotspot

2010 ◽  
Vol 24 (3) ◽  
pp. 209 ◽  
Author(s):  
Michael G. Rix ◽  
Mark S. Harvey ◽  
J. Dale Roberts
Keyword(s):  
New Species ◽  
Western Australia ◽  
Coastal Plain ◽  
Mitochondrial Protein ◽  
Biodiversity Hotspot ◽  
Rrna Genes ◽  
Protein Coding ◽  
Swan Coastal Plain ◽  
Coastal Species ◽  
Eastern Australia

South-western Western Australia is a biodiversity hotspot, with high levels of local endemism and a rich but largely undescribed terrestrial invertebrate fauna. Very few phylogeographic studies have been undertaken on south-western Australian invertebrate taxa, and almost nothing is known about historical biogeographic or cladogenic processes, particularly on the relatively young, speciose Quaternary sand dune habitats of the Swan Coastal Plain. Phylogeographic and taxonomic patterns were studied in textricellin micropholcommatid spiders belonging to the genus Raveniella Rix & Harvey. The Micropholcommatidae is a family of small spiders with a widespread distribution in southern Western Australia, and most species are spatially restricted to refugial microhabitats. In total, 340 specimens of Raveniella were collected from 36 surveyed localities on the Swan Coastal Plain and 17 non-Swan Coastal Plain reference localities in south-western Western Australia. Fragments from three nuclear rRNA genes (5.8S, 18S and ITS2), and one mitochondrial protein-coding gene (COI) were used to infer the phylogeny of the genus Raveniella, and to examine phylogeographic patterns on the Swan Coastal Plain. Five new species of Raveniella are described from Western Australia (R. arenacea, sp. nov., R. cirrata, sp. nov., R. janineae, sp. nov., R. mucronata, sp. nov. and R. subcirrata, sp. nov.), along with a single new species from south-eastern Australia (R. apopsis, sp. nov.). Four species of Raveniella were found on the Swan Coastal Plain: two with broader distributions in the High Rainfall and Transitional Rainfall Zones (R. peckorum Rix & Harvey, R. cirrata); and two endemic to the Swan Coastal Plain, found only on the western-most Quindalup dunes (R. arenacea, R. subcirrata). Two coastally restricted species (R. subcirrata, R. janineae) were found to be morphologically cryptic but genetically highly distinct, with female specimens morphologically indistinguishable from their respective sister-taxa (R. cirrata and R. peckorum). The greater Perth region is an important biogeographic overlap zone for all four Swan Coastal Plain species, where the ranges of two endemic coastal species join the northern and south-western limits of the ranges of R. peckorum and R. cirrata, respectively. Most species of Raveniella were found to occupy long, highly autapomorphic molecular branches exhibiting little intraspecific variation, and an analysis of ITS2 rRNA secondary structures among different species of Raveniella revealed the presence of an extraordinary hypervariable helix, ranging from 31 to over 400 nucleotides in length.

Environmental monitoring of acid sulphate soils in the Swan Coastal Plain, using hyperspectral methods

2006 ◽  
Vol 2006 (1) ◽  
pp. 1-4
Author(s):  
I. C. Lau ◽  
T. J. Cudahy ◽  
C.C.H. Ong ◽  
R.J.J. Vogwill ◽  
S. L. McHugh ◽  
...  
Keyword(s):  
Environmental Monitoring ◽  
Coastal Plain ◽  
Acid Sulphate ◽  
Acid Sulphate Soils ◽  
Swan Coastal Plain

Skeletal microstructure and mode of attachment in Palaeacis species (Anthozoa: Tabulata) from the Mississippian and Pennsylvanian of northeastern Oklahoma and northwestern Arkansas

1993 ◽  
Vol 67 (2) ◽  
pp. 167-178 ◽  
Author(s):  
Gregory E. Webb
Keyword(s):  
Growth Form ◽  
Growth Habit ◽  
Distal Portion ◽  
Free Living ◽  
Exterior Surface ◽  
Mode Of Attachment ◽  
Prostrate Growth ◽  
External Ornamentation

Three species of the Paleozoic coral Palaeacis are described from northeastern Oklahoma and northwestern Arkansas. Included are the Chesterian species P. carinata Girty and P. snideri n. nom., a replacement name for the junior homonym P. cuneata Snider, and the Desmoinesian? species P. erecta n. sp. Coralla of each species exhibit two types of microstructure that characterize two skeletal zones. The outer skeletal zone is composed of numerous parallel trabeculae, mostly between 0.2 and 0.3 mm in diameter, that lie perpendicular to, and have their accretionary surfaces on, the exterior surface of the corallum. Trabeculae are closely spaced laterally and are not organized into rows except uncommonly on the distal portion of some coralla. Where trabeculae coalesce into parallel rows, ornamentation on the corallum exterior consists of parallel ridges or rows of small nodes. Where trabeculae are irregularly arranged, external ornamentation consists of irregularly disposed nodes. The inner skeletal zone consists of radially fibrous stereoplasm arranged into discrete septal spines that coalesce into irregularly developed septal ridges in each calice. In P. erecta, septal spines merge into continuous layers of fibro-normal stereoplasm in some places. On the basis of microstructure, corallum morphology, and external ornamentation P. carinata and P. snideri can be allied with P. axinoides Smyth and P. robusta Webb. Palaeacis erecta falls within the same group on the basis of microstructure and ornament, but has a unique corallum morphology.Two distinct types of skeletal attachment occur in these Palaeacis species. Palaeacis carinata and P. snideri exhibit an encrusting attachment surface that results in a prostrate growth habit wherein smaller substrates were entirely engulfed, producing free-living coralla. Palaeacis erecta exhibits a small, circular attachment surface and an erect growth habit wherein most skeletal accretion occurs perpendicular to, and away from, the substrate. The substrate is not engulfed and the corallum remains attached and sessile throughout astogeny. Palaeacis erecta is, to date, the only Palaeacis species known to possess this erect, sessile growth form.

scholarly journals Hymenasplenium volubile: documentation of its gametophytes and the first record of a hemiepiphyte in the Aspleniaceae

2019 ◽  
Vol 124 (5) ◽  
pp. 829-835
Author(s):  
Jacob L Watts ◽  
Robbin C Moran ◽  
James E Watkins
Keyword(s):  
New World ◽  
Growth Form ◽  
Growth Habit ◽  
Microscopic Analysis ◽  
First Record ◽  
Laboratory Studies ◽  
Lower Margin ◽  
Fern Gametophyte ◽  
Gametophyte Ecology ◽  
Field Setting

Abstract Background and Aims Through careful field examination of the growth habit of the gametophytes and sporophytes of Hymenasplenium volubile across an ontogenetic series, we aim to understand better the evolution of epiphytism in this poorly understood group of ferns Methods We made field observations of H. volubile sporophytes and gametophytes, and brought specimens back to the lab for microscopic analysis. In the field, sporophytes at each ontogenetic stage were photographed to document the species’ growth habit. We used an existing phylogeny to optimize growth form of New World Hymenasplenium. Key Results Young sporophytes were at first fully epiphytic and produced one or two long feeding roots that extend to the soil where they branch profusely. The feeding roots remain in contact with the soil throughout the life of the plant. Thus, H. volubile is a hemiepiphyte. While immature, gametophytes are appressed to the tree trunk, but, as their gametangia mature, their lower margin lifts upward, imparting a shelf-like appearance to the thallus. The thallus attaches to the substrate by branched rhizoids produced along the margin of the thallus in contact with the substrate. Conclusions Hemiepiphytes are a key link in the evolution of epiphytic ferns and may act as a bridge between the forest floor and the canopy. Our finding is the first report of hemiepiphytism in Aspleniaceae, a large lineage with many epiphytic and terrestrial taxa. This work serves as an important model to understand the evolution of epiphytism in this group specifically and in ferns in general. The majority of our understanding of fern gametophyte biology is derived from laboratory studies. Our efforts represent a fundamental contribution to understanding fern gametophyte ecology in a field setting.

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