Phylogenetic reconstruction of African weakly electric fish (Campylomormyrus spp.) is suggestive of ancient introgression events.

The African weakly electric fish genus Campylomormyrus belongs to the species-rich family Mormyridae and comprises 15 described species. Previous species trees that focus on the genus, have included at most ten species. The resulting phylogenies have been used to explain the evolution of the species-specific electrical organ discharge (EOD) and interpreted in the context of sympatric speciation caused by disruptive selection.

Subtle stressors-Strong responses. Consistent negative effects of avian blood parasites on phenotypic and demographic traits across songbirds.

Stressors that subtly yet persistently deplete energetic resources-such as heat, pollutants or parasites-are well studied in laboratory and clinical settings, where their physiological effects are often well understood, yet their influence on phenotypic and demographic traits in free-living populations remains critically understudied. A prominent example is pathogens and parasites that cause sublethal infections, often considered as relatively benign, particularly in species adapted to their presence. However, parasite-induced effects on phenotypic and demographic traits are often inconsistent, leaving researchers uncertain about their impact and whether they have meaningful fitness consequences.

Evolution and Organisation of MHC II Genes in Harbour Porpoises: Insights From Long-Read Cetacean Genome Assemblies, Whole Genome Re-Sequencing and Locus-Specific Genotyping.

The Major Histocompatibility Complex (MHC) is a central element in the vertebrate immune system. While MHC genes are a common target of conservation genomic studies, it has been challenging to reliably amplify locus-specific alleles, which is especially problematic when studying endangered lineages, like some harbour porpoise (Phocoena phocoena) populations and subspecies. Here, we manually annotated all MHC II genes in the harbour porpoise genome and genotyped every exon 2 in 47 individuals (94 individuals for DRB1 and DQB genes) spanning six geographical regions, including the endangered Black Sea porpoise subspecies (Phocoena phocoena relicta) and the critically endangered Baltic proper population of the North Atlantic subspecies (P.

Long read genome unravels MHC I genomic architecture, evolution, and diversity loss in .

The major histocompatibility complex (MHC) genes are vital for the adaptive immune response in vertebrates and are widely used in conservation genetics to represent adaptive variation. Accurate genotyping of MHC alleles is essential for effective conservation, particularly for endangered species like the yellow cardinal (). However, the absence of locus-specific primers and the highly repetitive nature of these genes present a technical limitation when using short-read sequencing technologies.

Mitochondrial Genomes of Three Species (Ellobiidae; Gastropoda).

was recently divided into three genetically divergent cryptic species: , , and . We have assembled and annotated a mitochondrial genome for each of these species. Comparisons with other taxa showed that these three species possess a gene order that is distinct from the conserved gene order found in the six (out of nine available) Ellobiid genera.

Pathogen-induced alterations in fine-scale movement behaviour predict impaired reproductive success.

Pathogens play an important role in ecosystems and may impair fitness-enhancing activities such as foraging. However, the sublethal effects of pathogens on host movement behaviour and their subsequent impacts on reproductive success are poorly understood. In this study, we used high-resolution tracking to examine the movements of free-ranging European starlings () associated with sublethal avian blood parasite infections.

Genomics Reveal Population Structure and Intergeneric Hybridization in an Endangered South American Bird: Implications for Management and Conservation.

Genomics is an invaluable tool for conservation, particularly for endangered species impacted by wildlife trafficking. This study uses genomic data to provide new insights to aid conservation and management of endangered species, using as a case study the Yellow cardinal (), a bird endemic to southern South America severely affected by illegal trade and the transformation of its natural habitat. We explore population structure within the Yellow cardinal, delimiting management units and describing connectivity among them.

Organization of the stalk system on electrocytes in mormyrid weakly electric fish Campylomormyrus compressirostris.

The adult electric organ in weakly electric mormyrid fish consists of action-potential-generating electrocytes, structurally and functionally modified skeletal muscle cells. The electrocytes have a disc-shaped portion and, on one of its sides, numerous thin processes, termed stalklets. These unite to stalks leading to a single main stalk that carries the innervation site.

Sick without signs. Subclinical infections reduce local movements, alter habitat selection, and cause demographic shifts.

In wildlife populations, parasites often go unnoticed, as infected animals appear asymptomatic. However, these infections can subtly alter behaviour. Field evidence of how these subclinical infections induce changes in movement behaviour is scarce in free-ranging animals, yet it may be crucial for zoonotic disease surveillance.

A new type of spermiogenesis in teleost fish: Formation of the aflagellate sperm in Campylomormyrus compressirostris (Osteoglossomorpha: Mormyridae).

Osteoglossomorpha, the bony tongue fishes, show great variation in morphology, behavioural strategies, reproductive biology and gamete ultrastructure. The order Osteoglossiformes is the only vertebrate taxon, in which four types of sperm (monoflagellate, biflagellate and aflagellate aquasperm and the complex introsperm) have been described. It is also the only vertebrate lineage in which aflagellate spermatozoa exist.

No evidence for a role of MHC class II genotype in the chemical encoding of heterozygosity and relatedness in Antarctic fur seals.

Despite decades of research, surprisingly little is known about the mechanism(s) by which an individual's genotype is encoded in odour. Many studies have focused on the role of the major histocompatibility complex (MHC) owing to its importance for survival and mate choice. However, the salience of MHC-mediated odours compared to chemicals influenced by the rest of the genome remains unclear, especially in wild populations where it is challenging to quantify and control for the effects of the genomic background.

Gene and Allele-Specific Expression Underlying the Electric Signal Divergence in African Weakly Electric Fish.

In the African weakly electric fish genus Campylomormyrus, electric organ discharge signals are strikingly different in shape and duration among closely related species, contribute to prezygotic isolation, and may have triggered an adaptive radiation. We performed mRNA sequencing on electric organs and skeletal muscles (from which the electric organs derive) from 3 species with short (0.4 ms), medium (5 ms), and long (40 ms) electric organ discharges and 2 different cross-species hybrids.

Evolutionary history and seascape genomics of Harbour porpoises (Phocoena phocoena) across environmental gradients in the North Atlantic and adjacent waters.

The Harbour porpoise (Phocoena phocoena) is a highly mobile cetacean species primarily occurring in coastal and shelf waters across the Northern hemisphere. It inhabits heterogeneous seascapes broadly varying in salinity and temperature. Here, we produced 74 whole genomes at intermediate coverage to study Harbour porpoise's evolutionary history and investigate the role of local adaptation in the diversification into subspecies and populations.

Recruitment and migration patterns reveal a key role for seed banks in the meta-population dynamics of an aquatic plant.

Progressive habitat fragmentation threatens plant species with narrow habitat requirements. While local environmental conditions define population growth rates and recruitment success at the patch level, dispersal is critical for population viability at the landscape scale. Identifying the dynamics of plant meta-populations is often confounded by the uncertainty about soil-stored population compartments.

A new genome assembly of an African weakly electric fish (Campylomormyrus compressirostris, Mormyridae) indicates rapid gene family evolution in Osteoglossomorpha.

Background: Teleost fishes comprise more than half of the vertebrate species. Within teleosts, most phylogenies consider the split between Osteoglossomorpha and Euteleosteomorpha/Otomorpha as basal, preceded only by the derivation of the most primitive group of teleosts, the Elopomorpha. While Osteoglossomorpha are generally species poor, the taxon contains the African weakly electric fish (Mormyroidei), which have radiated into numerous species.

Intronic primers reveal unexpectedly high major histocompatibility complex diversity in Antarctic fur seals.

The major histocompatibility complex (MHC) is a group of genes comprising one of the most important components of the vertebrate immune system. Consequently, there has been much interest in characterising MHC variation and its relationship with fitness in a variety of species. Due to the exceptional polymorphism of MHC genes, careful PCR primer design is crucial for capturing all of the allelic variation present in a given species.

Behavioural Responses of Defended and Undefended Prey to Their Predator-A Case Study of Rotifera.

Predation is a strong species interaction causing severe harm or death to prey. Thus, prey species have evolved various defence strategies to minimize predation risk, which may be immediate (e.g.

DNA metabarcoding reveals impact of local recruitment, dispersal, and hydroperiod on assembly of a zooplankton metacommunity.

Understanding the environmental impact on the assembly of local communities in relation to their spatial and temporal connectivity is still a challenge in metacommunity ecology. This study aims to unravel underlying metacommunity processes and environmental factors that result in observed zooplankton communities. Unlike most metacommunity studies, we jointly examine active and dormant zooplankton communities using a DNA metabarcoding approach to overcome limitations of morphological species identification.

Intergenus F1-hybrids of African weakly electric fish (Mormyridae: Gnathonemus petersii ♂ × Campylomormyrus compressirostris ♀) are fertile.

Hybridisation is an important element of adaptive radiation in fish but data are limited in weakly electric mormyrid fish in this respect. Recently, it has been shown that intragenus hybrids (Campylomormyrus) are fertile and are able to produce F2-fish. In this paper, we demonstrate that even intergenus hybrids (Gnathonemus petersii ♂ × Campylomormyrus compressirostris ♀) are fertile.

Seed traits matter-Endozoochoric dispersal through a pervasive mobile linker.

Although many plants are dispersed by wind and seeds can travel long distances across unsuitable matrix areas, a large proportion relies on co-evolved zoochorous seed dispersal to connect populations in isolated habitat islands. Particularly in agricultural landscapes, where remaining habitat patches are often very small and highly isolated, mobile linkers as zoochorous seed dispersers are critical for the population dynamics of numerous plant species. However, knowledge about the quali- or quantification of such mobile link processes, especially in agricultural landscapes, is still limited.

A phylogeny of the genus Limia (Teleostei: Poeciliidae) suggests a single-lake radiation nested in a Caribbean-wide allopatric speciation scenario.

Objective: The Caribbean is an important global biodiversity hotspot. Adaptive radiations there lead to many speciation events within a limited period and hence are particularly prominent biodiversity generators. A prime example are freshwater fish of the genus Limia, endemic to the Greater Antilles.