The Thermal Tolerance of Springtails in a Tropical Cave, with the Description of a New Species (Collembola: Entomobryidae) from Thailand.

A new species of Collembola in the genus , , is described from a cave environment in Saraburi province, central Thailand. The new species is the second described species of the -group found in the country. It is most similar to Nilsai, Lima & Jantarit, 2022, which is also described from a Thai cave.

Phylogeny of Australian Acerentomidae species (Protura: Acerentomidae), with a key to identification.

The materials of three Acerentomidae species from Australia and Tasmania were studied. Additional morphological characters, such as chaetotaxy of head and notal segments, shape of body setae and porotaxy, are provided based on new materials of Australentulus westraliensis from Australia and Tasmanentulus tasmanicus from Tasmania. A new species, Amphientulus markstivensi, is described from Tasmania.

springs eternal: symbiosis in Collembola is associated with host ecology.

are endosymbiotic alpha-proteobacteria infecting a wide range of arthropods and nematode hosts with diverse interactions, from reproductive parasites to obligate mutualists. Their taxonomy is defined by lineages called supergroups (labelled by letters of the alphabet), while their evolutionary history is complex, with multiple horizontal transfers and secondary losses. One of the least recently derived, supergroup E, infects springtails (Collembola), widely distributed hexapods, with sexual and/or parthenogenetic populations depending on species.

A new group of species of the genus Megalothorax (Collembola, Neelidae) with Gondwanan distribution, and introducing an open interactive identification key of Megalothorax species.

Megalothorax Willem, 1900 is a genus of Neelidae (Collembola) with worldwide distribution. Three new species are described here: Megalothorax anterolenis sp. nov.

Two high-quality de novo genomes from single ethanol-preserved specimens of tiny metazoans (Collembola).

Background: Genome sequencing of all known eukaryotes on Earth promises unprecedented advances in biological sciences and in biodiversity-related applied fields such as environmental management and natural product research. Advances in long-read DNA sequencing make it feasible to generate high-quality genomes for many non-genetic model species. However, long-read sequencing today relies on sizable quantities of high-quality, high molecular weight DNA, which is mostly obtained from fresh tissues.

Fossil amber reveals springtails' longstanding dispersal by social insects.

Background: Dispersal is essential for terrestrial organisms living in disjunct habitats and constitutes a significant challenge for the evolution of wingless taxa. Springtails (Collembola), the sister-group of all insects (with Diplura), are reported since the Lower Devonian and are thought to have originally been subterranean. The order Symphypleona is reported since the early Cretaceous with genera distributed on every continent.

Breakdown of coevolution between symbiotic bacteria Wolbachia and their filarial hosts.

Wolbachia is an alpha-proteobacterial symbiont widely distributed in arthropods. Since the identification of Wolbachia in certain animal-parasitic nematodes (the Onchocercidae or filariae), the relationship between arthropod and nematode Wolbachia has attracted great interest. The obligate symbiosis in filariae, which renders infected species susceptible to antibiotic chemotherapy, was held to be distinct from the Wolbachia-arthropod relationship, typified by reproductive parasitism.

Phylogeny of the genus Willemia (Collembola: Hypogastruridae) and biogeography of the W. buddenbrocki-group with description of a new species from Ivory Coast (western Africa).

Willemia tondoh sp. nov. from the Ivory Coast (western Africa) is described and illustrated.

A complete insect from the Late Devonian period.

After terrestrialization, the diversification of arthropods and vertebrates is thought to have occurred in two distinct phases, the first between the Silurian and the Frasnian stages (Late Devonian period) (425-385 million years (Myr) ago), and the second characterized by the emergence of numerous new major taxa, during the Late Carboniferous period (after 345 Myr ago). These two diversification periods bracket the depauperate vertebrate Romer's gap (360-345 Myr ago) and arthropod gap (385-325 Myr ago), which could be due to preservational artefact. Although a recent molecular dating has given an age of 390 Myr for the Holometabola, the record of hexapods during the Early-Middle Devonian (411.

A new species and first record of the genus Triacanthella Schäffer, 1897 (Collembola, Poduromorpha, Hypogastruridae) for Africa.

The first species of the genus Triacanthella to be recorded from Africa is described. Triacanthella madibasp. n.

An application of dynamic homology to morphological characters: direct optimization of setae sequences and phylogeny of the family Odontellidae (Poduromorpha, Collembola).

The concept of character and the definition of the attribute are two major theoretical issues of phylogenetics. Lately, great progress has been made in the conceptual development of attributes as historical individuals undergoing series of transformations. While operational application of this ideographic concept of character has been possible since the publication of the direct optimization algorithm and POY software, it has been restricted to molecular characters only.

The evolutionary transition from subsocial to eusocial behaviour in Dictyoptera: phylogenetic evidence for modification of the "shift-in-dependent-care" hypothesis with a new subsocial cockroach.

Cockroaches have always been used to understand the first steps of social evolution in termites because they are close relatives with less complex and integrated social behaviour. Termites are all eusocial and ingroup comparative analysis would be useless to infer the origin of their social behaviour. The cockroach genus Cryptocercus was used as a so-called "prototermite" model because it shows key-attributes similar to the termites (except Termitidae): wood-feeding, intestinal flagellates and subsocial behaviour.

[Hexapoda phylogeny: implications for an aquatic origin hypothesis].

Emergence from an aquatic environment to the land is one of the major evolutionary transitions within the arthropods. It is often considered that the first hexapods, and especially the first Collembola, went from the sea through intermediate freshwater environments to colonize fully terrestrial ecosystems. To understand the ancestral ecology of hexapods, a phylogenetic framework is used.

Evolution on a shaky piece of Gondwana: is local endemism recent in New Caledonia?

New Caledonia is well known as a hot spot of biodiversity whose origin as a land mass can be traced back to the Gondwanan supercontinent. The local flora and fauna, in addition to being remarkably rich and endemic, comprise many supposedly relictual groups. Does the New Caledonian biota date back to Gondwanan times, building up its richness and endemism over 100 Myr or does it result from recent diversifications after Tertiary geological catastrophic events? Here we use a molecular phylogenetic approach to answer this question with the study of the Neocaledonian cockroach genus Angustonicus belonging to the subfamily Tryonicinae from Australia and New Caledonia.

Mitochondrial genome data alone are not enough to unambiguously resolve the relationships of Entognatha, Insecta and Crustacea sensu lato (Arthropoda).

An analysis of the relationships of the major arthropod groups was undertaken using mitochondrial genome data to examine the hypotheses that Hexapoda is polyphyletic and that Collembola is more closely related to branchiopod crustaceans than insects. We sought to examine the sensitivity of this relationship to outgroup choice, data treatment, gene choice and optimality criteria used in the phylogenetic analysis of mitochondrial genome data. Additionally we sequenced the mitochondrial genome of an archaeognathan, Nesomachilis australica, to improve taxon selection in the apterygote insects, a group poorly represented in previous mitochondrial phylogenies.

Mapping characters on a tree with or without the outgroups.

A character of special interest in evolutionary studies is usually optimized on a phylogenetic tree, with or without the outgroups employed in that analysis. Both practices are never justified and look like arbitrary choices. Focusing on one example, we draw the conclusion that authors retain or remove outgroups depending on the way these outgroups sample the diversity of states of the character(s) of special interest.

The geometric mean length, a new statistic to describe the distribution of character steps on a tree.

The geometric mean length (GML) is proposed as a new statistic aimed at describing the evenness of character changes on a tree for a given set of character optimizations. It is the geometric mean of the number of steps on each branch of the tree, varying between a maximum value when all branch lengths are equal, and a minimum value when all branches but one have only one character step. It can be scaled according to its theoretical maximum value, thus indicating a relative GML that allows a comparison of the evenness of character steps between different tree topologies.

Were the first springtails semi-aquatic? A phylogenetic approach by means of 28S rDNA and optimization alignment.

Emergence from an aquatic environment to the land is one of the major evolutionary transitions within the arthropods. It is often considered that the first hexapods, and in particular the first springtails, were semi-aquatic and this assumption drives evolutionary models towards particular conclusions. To address the question of the ecological origin of the springtails, phylogenetic analyses by optimization alignment were performed on D1 and D2 regions of the 28S rDNA for 55 collembolan exemplars and eight outgroups.

Is Psammophily an Evolutionary Dead End? A Phylogenetic Test in the Genus Willemia (Collembola: Hypogastruridae).

The law of the unspecialized states that specialized taxa have evolved from more generalized ancestors. Moreover, it is usually assumed that ecological specialization is irreversible and hence leads to extinction. This study aims to test these assumptions using a phylogenetic framework in a case study within the springtail genus Willemia and its diverse life habits.