ABSTRACT The macroanatomy of the digestive tract is typically interpreted in relation to trophic biology, potentially overlooking other determinants of digestive system design. Here, we investigate how digestive tract morphology reflects the interaction between anatomy, molecular makeup, taxon‐specific physiology, and ecological context. We show that several taxa occupying similar trophic niches, tenrecs ( Setifer setosus and Echinops telfairi ), African hedgehogs ( Atelerix and Paraechinus spp.), and the European hedgehog ( Erinaceus europaeus ), have similar gastrointestinal morphology (a simple stomach and an intestinal tube of largely homogeneous diameter without a cecum) yet differ markedly in total intestinal length, mainly due to differences in small intestine length. S. setosus has a comparable relative length of the intestinal regions to E. europaeus , while Atelerix albiventris has a slightly elongated large intestine. Although S. setosus exhibits enhanced absorptive capacity at the microanatomical level, reflected in higher serosal surface area enlargement factors, its shorter absolute intestinal length constrains total absorptive surface. Thus, E. europaeus possesses approximately 2.5 times the absorptive surface of A. albiventris and five times that of S. setosus . We suggest that these differences are related to differences in metabolic intensity, namely, energetic turnover and food‐processing rates. This is determined by both the taxon‐specific (Afrotheria vs. Laurasiatheria) pace of life and the extrinsic challenges of seasonal habitats with periods of resource scarcity and abundance, during which reproduction and adipose reserve accretion for the next winter occur. This supports the view that digestive tract morphology is shaped by the interaction of dietary, ecological, and phylogeny‐related physiological constraints.
ABSTRACT Public mitochondrial genome records vary considerably in annotation quality and nomenclature, complicating comparative analyses of gene content and gene order. We developed MitoOmicsDB, a web‐based platform for the standardized curation, retrieval, visualization, and analysis of metazoan mitochondrial genomes. Its NCBI2GO pipeline normalizes gene names, strand orientation, coordinate origins, transfer RNA identities, and other annotation features, while retaining unresolved cases for manual examination. Source annotations, automated results, and subsequent manual corrections remain linked to their original accessions to support review and reuse. The current source dataset contains 61 778 metazoan mitochondrial genome records, although taxonomic representation and the extent of curation remain uneven. The systematically processed vertebrate subset includes 7317 complete reference genomes from five major groups and represents 694 distinct gene order types. Users can search and download processed records, visualize mitochondrial gene arrangements, and upload GenBank files for annotation cleaning. The resulting data can be exported for downstream gene order analyses. By combining automated normalization with taxon‐informed manual curation, MitoOmicsDB provides a shared framework for improving annotation consistency and facilitating broad comparative studies of mitochondrial genome organization across Metazoa.
ABSTRACT Sirenians and marine carnivorans represent unique mammalian lineages that have transitioned from terrestrial to aquatic life. Although they serve as vital indicators of marine ecosystem health, nearly half of these species are threatened with extinction. However, a comprehensive database capturing both their biological traits and environmental variables has been lacking. To address this gap, we constructed a standardized data repository for all 46 species, integrating 56 variables across morphological and physiological, life‐history, ecological, biogeographical, environmental, and conservation dimensions. Additionally, we collected data on body size, coloration, distributional range, and extinction risk for all 22 subspecies. At the species level, environmental variables were nearly fully quantified, while trait completeness varied across other categories, ranging from 46.34%–100.00% for morphology and 20.00%–100.00% for life history. Using this repository, our phylogenetic models revealed that research effort was heavily biased, with migratory species and those described earlier possessing much higher data completeness. Furthermore, geographic range size emerged as the primary predictor of extinction risk. These findings highlight the urgent need to prioritize research and conservation efforts for these species, particularly those with restricted ranges or recent descriptions. Taken together, our integrated dataset fills historical knowledge gaps and provides a robust empirical foundation for guiding targeted, spatially explicit conservation actions for these vulnerable marine mammals.
The cognitive benefits of having a large brain must outweigh its substantial energetic demands for such an organ to evolve. The cognitive buffer hypothesis proposes that large brains facilitate survival in complex environments via flexible behaviors. Because active predator evasion is likely more cognitively demanding than a cryptic lifestyle, we reasoned that the evolution of crypsis could relax selection on brain size. To test this hypothesis, we examined the effect of dorsal crypsis, ventral crypsis, and granular glands on relative total brain evolution in eight toad species. As predicted, total relative brain size was negatively associated with dorsal crypsis across species, but was not related to either the volume or the count of granular glands. Additionally, because certain brain regions may be specifically involved in predator evasion, we assessed relationships between five major brain region sizes and both dorsal crypsis and granular gland traits. Only the olfactory nerves and telencephalon showed negative associations with dorsal crypsis, whereas optic tectum volume correlated positively with granular gland volume. These regions support complex evasion strategies. Our findings indicate that increased dorsal crypsis relaxes selection on cognitively demanding evasion, leading to smaller brains. Thus, crypsis evolution is a previously underexplored factor in vertebrate brain anatomy evolution.
ABSTRACT “Community informant” species serve as critical sources of information. However, interactions between multiple informant species in complex systems remain unclear, including whether they jointly contribute vocalizations and thus public information, eavesdrop on each other, or do not interact, and whether joint contributions provide benefits through complementary or supplementary mechanisms. We elicited mobbing calls using an owl model and alarm calls using a raptor model inside mixed‐species flocks (MSFs) in a two‐year survey on a 1650 km latitudinal gradient (18.7°N–33.7°N) in China, across which bird communities transition from babbler dominance in the south to tits in the north. We also constructed social networks to examine structural patterns along the gradient and assessed the influence of latitude on network metrics and the effect of group composition (Babbler‐Tit, Babbler, Tit, None) on vocal responses. Social network metrics peaked in interaction strength (for mobs) and cohesion (for MSFs) at mid‐latitudes. Alarm calls were brief and dominated by one babbler and two tit species, whereas mobbing calls were long‐lasting and contributed by many species (averaging 4.2 per trial). In small mobbing assemblages (1–5 species), Babbler‐Tit groups recruited up to 2.4 times more individuals and elicited 2.1 times more calls. Babbler‐Tit MSFs also involved up to 1.6 times more vocal species and generated vocalizations with up to 12.2 times broader frequency ranges, which potentially could be detected by more species. Therefore, protecting community informants and complex systems is essential to maintain information networks that underpin ecosystem resilience.
