Diversity

Microsatellites or simple sequence repeats (SSRs) are valuable markers for understanding genome structure, function, and evolution. However, their distribution and characteristics remain largely unexplored in cricket species. We conducted a genome-wide identification and analysis of perfect (P-SSRs), compound (C-SSRs), and imperfect SSRs (I-SSRs) across five cricket genomes. The total number of SSRs ranged from 2,350,765 to 3,299,527, representing 5.37–7.27% of the genomes. Abundance followed the pattern I-SSRs > P-SSRs > C-SSRs across genomic regions (genome, intergenic, intronic, and coding sequences). Total SSR number, length, abundance and density showed no significant correlation with genome size. Trinucleotide repeats were consistently the most common P-SSR type. The (AAT)_n motif predominated in genomes, intergenic, and introns, while (CCG)_n was most frequent in coding sequences. Consequently, AT-rich repeats dominated non-coding regions, whereas GC-rich repeats were enriched in coding sequences. Coefficient of variation analysis of repeat copy numbers revealed distinct trends in P-SSR distribution across genomic regions and species. Functional annotation of coding sequences containing P-SSRs indicated involvement in binding, signal transduction, and transcription. This study represents, to our knowledge, the first comprehensive subtribe-level comparative analysis of SSRs in crickets, providing new insights into their genomic architecture.

Plant invasions severely threaten the stability and biodiversity of fragile ecosystems in karst areas. Elucidating the microbial mechanisms underlying the interactions between invasive plants and native plants in rhizosphere soil is crucial for preventing plant invasions. In this study, high-throughput sequencing was used to compare the differences in rhizosphere fungi between two invasive and native plants in the Guizhou karst region. These findings provide theoretical support for understanding the ecological impact of invasive plants and for developing ecological management strategies based on soil microorganisms. The results revealed the following: (1) A total of 16 soil samples were included in the study, which comprised 1 phylum, 50 classes, 112 orders, 245 families, 463 genera and 629 species. (2) No significant differences were observed in the Ace, Chao, Shannon, Simpson and Sobs indices of the rhizosphere fungal communities between invasive plants and native plants (p > 0.05). (3) At the phylum level, no significant difference was observed in the community compositions of invasive and native plants; the dominant phyla were Ascomycota, Mortierellomycota and Basidiomycota; at the genus level, there were significant differences in the community composition of invasive and native plants, and the relative abundances of Minimedusa, Monocillium and Gymnopus in the rhizosphere soil of invasive plants were significantly higher (p < 0.05). (4) Functional predictions based on FUNGuild indicated a higher relative abundance of saprotrophic fungi associated with invasive plants. Community assembly processes for both invasive and native plants were primarily governed by stochastic ecological processes (e.g., drift). These findings suggest that plant invasion is associated with shifts in the composition and potential ecological functions of rhizosphere fungal communities in the karst area.

The Late Cretaceous deposits of Morocco have yielded one of the richest and most diverse assemblages of marine reptiles in the world, with the mosasaurids representing the dominant group. Among the most common mosasaurs are members of the subfamily Halisaurinae. Halisaurines ranged in size from the relatively small Halisaurus, which reached 4–5 m in length, to the larger Pluridens serpentis, which may have reached 7.5 m in length. Here we report a new, giant species of Pluridens, Pluridens imelaki. The new Pluridens is characterized by a slender, rectangular snout, a T-shaped premaxilla–maxilla junction, interlocking premaxilla–maxilla joint, a prominent dorsal ridge on the premaxilla, an exceptionally long and slender mandible, a tooth count of ~25 dentary teeth, straight, triangular tooth crowns that are strongly bent back just above the tooth–root junction, a low coronoid process and a tall and slender retroarticular process. The skull is 1.25 m long, suggesting a body length of ~9 m or more, comparable in size to large predators such as Thalassotitan. Differences between P. imaleki and P. serpentis in the jaw and tooth structure, eye size and innervation of the rostrum, as well as overall size, suggest they had different foraging strategies and occupied distinct ecological niches. Pluridens imelaki reveals that Halisaurinae were not only more species-rich than previously recognized, but also exhibited greater diversity in tooth morphology, jaw shape, and body size than previously thought. Rather than simply being outcompeted by Mosasaurinae, the Halisaurinae staged a minor adaptive radiation in the Late Cretaceous and were important members of the ecosystem in low latitudes. Pluridens imelaki appears to have been exceptionally rare in the phosphates, being documented by only a single specimen among the many hundreds of mosasaur remains recovered over many years. This underscores how the species richness of the phosphates and other diverse assemblages is driven by rare taxa that are only revealed through extensive sampling.