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Coronuloid barnacles are epibionts of several marine vertebrates (including cetaceans and sea turtles) as well as invertebrates, and are assigned to two families of turtle barnacles (Chelonibiidae Pilsbry, 1916 and Platylepadidae Newman & Ross, 1976) and one family of whale barnacles (Coronulidae Leach, 1817). Chelonibiids and coronulids have a scanty, albeit significant fossil record extending back to the Eocene and Pliocene, respectively; in turn, the fossil record of platylepadids is limited to a single record from the Upper Pleistocene. Here we report on an isolated carinolateral compartment of Platylepas Gray, 1825, the type genus of the family, from Lower Pleistocene (Gelasian) epibathyal deposits exposed at Milazzo (Sicily, Italy). This specimen is here designated holotype of a new species, †Platylepas mediterranea sp. nov. We argue that, like most extant members of Platylepas, †P. mediterranea sp. nov. lived partially embedded in the skin of a sea turtle. This record of an extinct platylepadid – the first from the Mediterranean region and the second worldwide – pushes back the fossil record of Platylepadidae to the lowermost Quaternary, thus possibly supporting an even earlier (e.g., Neogene) timing for the origin of this family and adding a new chapter to the evolutionary history of one of the most diverse and successful lineages of epizoic crustaceans.
Microthlaspi erraticum is widely distributed in temperate Eurasia, but restricted to Ca2+-rich habitats, predominantly on white Jurassic limestone, which is made up by calcium carbonate, with little other minerals. Thus, naturally occurring Microthlaspi erraticum individuals are confronted with a high concentration of Ca2+ ions while Mg2+ ion concentration is relatively low. As there is a competitive uptake between these two ions, adaptation to the soil condition can be expected. In this study, it was the aim to explore the genomic consequences of this adaptation by sequencing and analysing the genome of Microthlaspi erraticum. Its genome size is comparable with other diploid Brassicaceae, while more genes were predicted. Two Mg2+ transporters known to be expressed in roots were duplicated and one showed a significant degree of positive selection. It is speculated that this evolved due to the pressure to take up Mg2+ ions efficiently in the presence of an overwhelming amount of Ca2+ ions. Future studies on plants specialized on similar soils and affinity tests of the transporters are needed to provide unequivocal evidence for this hypothesis. If verified, the transporters found in this study might be useful for breeding Brassicaceae crops for higher yield on Ca2+-rich and Mg2+ -poor soils.
The island arc of the Lesser Antilles lies at the eastern margin of the Caribbean Sea in the Western Hemisphere, and stretches from the eastern end of the islands of the Greater Antilles (at the Virgin Islands), south to a position near the continental islands of Trinidad and Tobago at the north eastern corner of South America. The islands are a part of the West Indian Islands biodiversity “hotspot” and have been available for terrestrial colonization for about the past 15 million years. This is a status report on present knowledge of the beetle faunas of these islands, which is composed of 90 families, 1210 genera, and 2612 recognized species. Many additional species are not yet identified, or are unnamed, or remain to be discovered. Reported for the first time from the Lesser Antilles are four families, 49 genera, 105 species, and 1253 new island records. The largest families are Curculionidae (588 species), Staphylinidae (389 species), Chrysomelidae (181 species), Tenebrionidae (142 species), Cerambycidae (138 species), Scarabaeidae (127 species), and Carabidae (126 species). There are differing patterns of species distributions: 154 species are probably introduced by human activities; 985 are endemic species (limited to a single island); 465 are species endemic to more than one island of the Lesser Antilles; 212 are species limited to just islands of the West Indies; and 800 are native (naturally occurring) species which also have part of their distributional range in North, Central, or South America. Most of the widely distributed beetle fauna has probably come from South America by over-water dispersal. There is no compelling evidence for a vicariance origin of any part of the beetle fauna. Earlier colonists have had more time to form endemic genera (18) and endemic species. The more widely distributed species probably represent distributions achieved in and since the Pleistocene.
Hypotheses on the age and possible antiquity of the modern deep-sea fauna put forward to date almost all agree on the assumption that the deep-sea fauna is largely the result of colonisation from shallow-water environments. Here, the fossil record of the Ophiacanthidae, a modern deep-sea brittle star family with extensive fossil occurrences at shelf depths, is systematically traced against a calibrated phylogeny. Several lines of evidence suggest that the Ophiacanthidae originated and greatly diversified in the deep sea, with most extant clades having diverged by the end of the Triassic at the latest. During the Jurassic, the family temporarily invaded shelf environments, attaining relative abundances and diversities comparable to those found in coeval and modern deep-sea settings, and gradually declined in abundance subsequently, to become largely restricted to the deep-sea again. The pattern of temporary expansion to shelf environments suggested here underpins the potential of deep-sea environments to contribute significantly to shallow-water biodiversity; an aspect that has mostly been neglected so far. It is speculated that the large-scale ophiacanthid invasion of shelf environments around the Triassic- Jurassic boundary was initiated by a change from thermohaline to halothermal circulation, attenuating the thermal stratifi cation of the water column and thus providing opportunities for enhanced vertical migration of marine taxa.
Inhibitory interneurons govern virtually all computations in neocortical circuits and are in turn controlled by neuromodulation. While a detailed understanding of the distinct marker expression, physiology, and neuromodulator responses of different interneuron types exists for rodents and recent studies have highlighted the role of specific interneurons in converting rapid neuromodulatory signals into altered sensory processing during locomotion, attention, and associative learning, it remains little understood whether similar mechanisms exist in human neocortex. Here, we use whole-cell recordings combined with agonist application, transgenic mouse lines, in situ hybridization, and unbiased clustering to directly determine these features in human layer 1 interneurons (L1-INs). Our results indicate pronounced nicotinic recruitment of all L1-INs, whereas only a small subset co-expresses the ionotropic HTR3 receptor. In addition to human specializations, we observe two comparable physiologically and genetically distinct L1-IN types in both species, together indicating conserved rapid neuromodulation of human neocortical circuits through layer 1.
Phylogenetic reconstruction from transposable elements (TEs) offers an additional perspective to study evolutionary processes. However, detecting phylogenetically informative TE insertions requires tedious experimental work, limiting the power of phylogenetic inference. Here, we analyzed the genomes of seven bear species using high-throughput sequencing data to detect thousands of TE insertions. The newly developed pipeline for TE detection called TeddyPi (TE detection and discovery for Phylogenetic Inference) identified 150,513 high-quality TE insertions in the genomes of ursine and tremarctine bears. By integrating different TE insertion callers and using a stringent filtering approach, the TeddyPi pipeline produced highly reliable TE insertion calls, which were confirmed by extensive in vitro validation experiments. Analysis of single nucleotide substitutions in the flanking regions of the TEs shows that these substitutions correlate with the phylogenetic signal from the TE insertions. Our phylogenomic analyses show that TEs are a major driver of genomic variation in bears and enabled phylogenetic reconstruction of a well-resolved species tree, despite strong signals for incomplete lineage sorting and introgression. The analyses show that the Asiatic black, sun, and sloth bear form a monophyletic clade, in which phylogenetic incongruence originates from incomplete lineage sorting. TeddyPi is open source and can be adapted to various TE and structural variation callers. The pipeline makes it possible to confidently extract thousands of TE insertions even from low-coverage genomes (∼10×) of nonmodel organisms. This opens new possibilities for biologists to study phylogenies and evolutionary processes as well as rates and patterns of (retro-)transposition and structural variation.
The ostracod genus Bennelongia De Deckker & McKenzie, 1981 occurs in Australia and New Zealand. We redescribe B. nimala from the Northern Territory and describe six new species from Western Australia belonging to the B. nimala (five species) and B. triangulata sp. nov. (one species) lineages: B. tirigie sp. nov., B. koendersae sp. nov., B. pinderi sp. nov., B. muggon sp. nov., B. shieli sp. nov. and B. triangulata sp. nov. For six of these seven species, we could construct molecular phylogenies and parsimonious networks based on COI sequences. We tested for specific status and for potential cryptic diversity of clades with Birky’s 4 theta rule. The analyses support the existence of these six species and the absence of cryptic species in these lineages. Bennelongia triangulata sp. nov. is a common species in the turbid claypans of the Murchison/Gascoyne region. Bennelongia nimala itself is thus far known only from the Northern Territory. Bennelongia tirigie sp. nov., B. pinderi sp. nov. and B. muggon sp. nov. occur in the Murchison/Gascoyne region, whereas B. koendersae sp. nov. and B. shieli sp. nov. are described from the Pilbara. With the six new species described here, the genus Bennelongia now comprises 31 nominal species.
The ostracod genus Bennelongia De Deckker & McKenzie, 1981 is endemic to Australia and New Zealand. Extensive sampling in Western Australia (WA) revealed a high specific and largely undescribed diversity. Here, we describe seven new species belonging to the B. barangaroo lineage: B. timmsi sp. nov., B. gnamma sp. nov., B. hirsuta sp. nov., B. ivanae sp. nov., B. mcraeae sp. nov., B. scanloni sp. nov. and B. calei sp. nov., and confirm the presence of an additional species, B. dedeckkeri, in WA. For five of these eight species, we could construct molecular phylogenies and parsimonious networks based on COI sequences. We also tested for cryptic diversity and specific status of clusters with a statistical method based on the evolutionary genetic species concept, namely Birky’s 4 theta rule. The analyses support the existence of these five species and a further three cryptic species in the WA B. barangaroo lineage. The molecular evidence was particularly relevant because most species described herein have very similar morphologies and can be distinguished from each other only by the shape, size and position of the antero-ventral lapel on the right valve, and, in sexual populations, by the small differences in shape of the hemipenes and the prehensile palps in males. Four species of the WA B. barangaroo lineage occur in small temporary rock pools (gnammas) on rocky outcrops. The other four species are mainly found in soft bottomed seasonal water bodies. One of the latter species, B. scanloni sp. nov., occurs in both claypans and deeper rock pools (pit gnammas). All species, except for B. dedeckkeri, originally described from Queensland, have quite clearly delimited distributions in WA. With the seven new species described here, the genus Bennelongia now comprises 25 nominal species but several more await formal description.
Unc-51-like kinase 4 (ULK4) is a pseudokinase that has been linked to the development of several diseases. Even though sequence motifs required for ATP binding in kinases are lacking, ULK4 still tightly binds ATP and the presence of the co-factor is required for structural stability of ULK4. Here, we present a high-resolution structure of a ULK4-ATPγS complex revealing a highly unusual ATP binding mode in which the lack of the canonical VAIK motif lysine is compensated by K39, located N-terminal to αC. Evolutionary analysis suggests that degradation of active site motifs in metazoan ULK4 has co-occurred with an ULK4-specific activation loop, which stabilizes the C helix. In addition, cellular interaction studies using BioID and biochemical validation data revealed high confidence interactors of the pseudokinase and armadillo repeat domains. Many of the identified ULK4 interaction partners were centrosomal and tubulin-associated proteins and several active kinases suggesting interesting regulatory roles for ULK4.
Three fossil leafhopper inclusions from Eocene Baltic amber, representing three new extinct genera and species, are described and illustrated. Eomegophthalmus lithuaniensis gen. et sp. nov. is tentatively placed in Megophthalminae, although it may represent the stem group from which Megophthalminae, Ulopinae, and Membracidae arose. Xestocephalites balticus gen. et sp. nov. and Brevaphrodella nigra gen. et sp. nov. are placed in Aphrodinae: Xestocephalini based on the structure of the head, leg chaetotaxy, and male genital capsule. These new genera and species represent the oldest known representatives of their respective subfamilies and the latter is the oldest known brachypterous adult leafhopper.