Publications by authors named "Bruce A Marshall"
Natural history collections worldwide contain a plethora of mollusc shells. Recent studies have detailed the sequencing of DNA extracted from shells up to thousands of years old and from various taphonomic and preservational contexts. However, previous approaches have largely addressed methodological rather than evolutionary research questions.
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- The study focuses on accurately identifying species and their evolutionary lineages through the analysis of genetic and morphological variations in Penion marine snails from New Zealand, comparing living populations and fossils over time.
- Findings reveal that while genetic and shell morphology generally align in identifying current species, some taxonomic splits are incorrect due to shell size being an unreliable measure for species delimitation.
- An unexpected result shows that by re-evaluating the classification of a fossil specimen, the researchers observed a period of morphological stasis in shell shape, suggesting that lineage identification significantly influences our understanding of evolutionary patterns.
Article Synopsis
- The study examines the connection between shell shape and genetic inheritance in three marine snail genera: Penion, Antarctoneptunea, and Kelletia, to see if shell morphology represents their evolutionary relationships.
- Researchers analyzed DNA and shell variations across sixteen species, finding that while the genera are genetically distinct (monophyletic), some species within Penion present uncertainties in their classification.
- Results indicate that shell form effectively distinguishes the genera and aligns with major evolutionary splits, although the ability to accurately identify species and finer phylogenetic groups using morphology alone is limited.
This data article provides genome statistics, phylogenetic networks and trees for a phylogenetic study of Southern Hemisphere Buccinulidae marine snails [1]. We present alternative phylogenetic reconstructions using mitochondrial genomic and 45S nuclear ribosomal cassette DNA sequence data, as well as trees based on short-length DNA sequence data. We also investigate the proportion of variable sites per sequence length for a set of mitochondrial and nuclear ribosomal genes, in order to examine the phylogenetic information provided by different DNA markers.
View Article and Find Full Text PDFThe Mediterranean Sea is increasingly under threat from invasive species that may negatively affect biodiversity and/or modify ecosystem structure and function. The bivalve mollusc Pinctada imbricata radiata is listed among the 100 most invasive species in the Mediterranean. A first finding of an established population of P.
View Article and Find Full Text PDFUnder current marine snail taxonomy, the majority of whelks from the Southern Hemisphere (Buccinulidae) are hypothesised to represent a monophyletic clade that has evolved independently from Northern Hemisphere taxa (Buccinidae). Phylogenetic analysis of mitochondrial genomic and nuclear ribosomal DNA sequence data indicates that Southern Hemisphere taxa are not monophyletic, and results suggest that dispersal across the equator has occurred in both directions. New Zealand buccinulid whelks, noted for their high endemic diversity, are also found to not be monophyletic.
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- The occupancy of a species—how much space it occupies over time—changes due to big ecological factors and historical events.
- A study of marine mollusks in New Zealand revealed that their occupancy tends to rise to a peak and then decline, suggesting that those species at higher risk of extinction have been in decline for a long time.
- This pattern contrasts with what is seen in incumbency, as species do not remain stable at their peak occupancy but tend to experience extended periods of increase and decline.