Mattia Giacomelli

• PhD Student at University of Bristol

Ecdysozoans (Phyla Arthropoda, Kinorhyncha, Loricifera, Nematoda, Nematomorpha, Onychophora, Priapulida, Tardigrada) are invertebrates bearing a tough, periodically moulted cuticle that predisposes them to exceptional preservation. Ecdysozoans dominate the oldest exceptionally-preserved bilaterian animal biotas in the early-mid Cambrian (∼520–508 M...

Genomic data allowed for a detailed resolution of the tree of life. Yet, tricky nodes such as the root of the animal, plants, eukaryotes, bacterial and archaeal trees remain unresolved. Genomic datasets are heterogeneous as genes and species evolve under different selective pressures, impending the efficacy of evolutionary analyses. Amino acid reco...

Insects comprise over half of all described animal species. Together with the Protura (coneheads), Collembola (springtails) and Diplura (two-pronged bristletails), insects form the Hexapoda, a terrestrial arthropod lineage characterised by possessing six legs. Exponential growth of genome-scale data for the hexapods has substantially altered our un...

We found support for clades that clarified key controversies in chelicerate phylogeny. Foremost among these is the alliance between mites and ticks, resulting in a grouping of arachnids with even more species than spiders. More broadly, our results suggest that the success of the arachnid order was most likely based on a single terrestrialisation e...

Tardigrada, the water bears, are microscopic animals with walking appendages, that are members of Ecdysozoa, the clade of moulting animals that also includes Nematoda (round worms), Nematomorpha (horsehair worms), Priapulida (penis worms), Kinorhyncha (mud dragons), Loricifera (loricated animals), Arthropoda (insects, spiders centipedes, crustacean...

Sponges (Porifera) are highly effective ecosystem engineers, playing a critical role in global biogeochemical processes, including the nitrogen, carbon, and silica cycles. Because of that, they have been closely linked to the evolution of Earth's environments. However, determining the evolutionary history of sponges has posed challenges. Molecular...

Genomic data allowed a detailed resolution of the tree of life, but “tricky nodes'' such as the root of the animals remain unresolved. Genome-scale datasets are heterogeneous as genes and species are exposed to different pressures, and this negatively impacts phylogenetic accuracy. We use simulated genomic-scale datasets and show that recoding amin...

Beetles constitute the most biodiverse animal order with over 380 000 described species and possibly several million more yet unnamed. Recent phylogenomic studies have arrived at considerably incongruent topologies and widely varying estimates of divergence dates for major beetle clades. Here, we use a dataset of 68 single-copy nuclear protein-codi...

With over 380,000 described species and possibly several million more yet unnamed, beetles represent the most biodiverse animal order. Recent phylogenomic studies have arrived at considerably incongruent topologies and widely varying estimates of divergence dates for major beetle clades. Here we use a dataset of 68 single-copy nuclear protein codin...

The evolution of wings propelled insects to their present mega-diversity. However, interordinal relationships of early-diverging winged insects and the timescale of their evolution are difficult to resolve, in part due to uncertainties in the placement of the enigmatic and species-poor order Zoraptera. The 'Zoraptera problem' has remained a content...

Fleas (Siphonaptera) are medically important blood-feeding insects responsible for spreading pathogens such as plague, murine typhus, and myxomatosis. The peculiar morphology of fleas resulting from their specialised ectoparasitic lifestyle has meant that the phylogenetic position of this diverse and medically important group has remained one of th...

Stick and leaf insects (Phasmatodea) are a distinctive insect order whose members are characterized by mimicking various plant tissues such as twigs, foliage and bark. Unfortunately, the phylogenetic relationships among phasmatodean subfamilies and the timescale of their evolution remain uncertain. Recent molecular clock analyses have suggested a C...

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

The relationships of crustaceans and hexapods (Pancrustacea) have been much discussed and partially elucidated following the emergence of phylogenomic data sets. However, major uncertainties still remain regarding the position of iconic taxa such as Branchiopoda, Copepoda, Remipedia, and Cephalocarida, and the sister group relationship of hexapods....