ABSTRACT
The phylum Acanthocephala is an important monophyletic group of parasites, with adults parasitic in the digestive tracts of all major vertebrate groups. Acanthocephalans are of veterinary, medical, and economic importance due to their ability to cause disease in domestic animals, wildlife, and humans. However, the current genetic data for acanthocephalans are sparse, both in terms of the proportion of taxa surveyed and the number of genes sequenced. Consequently, the basic molecular phylogenetic framework for the phylum is still incomplete. In the present study, we reported the first complete mitochondrial genome from a representative of the family Pseudoacanthocephalidae Petrochenko, 1956. The mitogenome of Pseudoacanthocephalus bufonis (Shipley, 1903) is 14,056 bp in length, contains 36 genes (12 protein-coding genes (PCGs) (lacking atp8), 22 tRNA genes, and 2 rRNA genes (rrnL and rrnS)) and two non-coding regions (NCR1 and NCR2), and displayed the highest GC-skew in the order Echinorhynchida. Phylogenetic results of maximum likelihood (ML) and Bayesian inference (BI) using the amino acid sequences of 12 protein-coding genes in different models provided further evidence for the resurrection of the family Pseudoacanthocephalidae and also supported that the order Echinorhynchida is paraphyletic. A monophyletic clade comprising P. bufonis and Cavisoma magnum suggests a close affinity between Pseudoacanthocephalidae and Cavisomatidae. Our phylogenetic analyses also showed that Polymorphidae has a closer relationship with Centrorhynchidae than Plagiorhynchidae in the monophyletic order Polymorphida.
ABSTRACT
Soft scale insects (Hemiptera, Coccidae) are important pests of various agricultural and horticultural crops and ornamental plants. They have negative impacts on agriculture and forestry. The tribe Coccini represents one of the most ancient evolutionary lineages of soft scale insects. However, no complete Coccini mitochondrial genome (mitogenome) is available in public databases. Here, we described the complete mitogenome of Coccushesperidum L., 1758. The 15,566 bp mitogenome of C.hesperidum had a high A+T content (83.4%) and contained a typical set of 37 genes, with 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNAs) and two ribosomal RNA genes (rRNAs). Only seven tRNAs had the typical clover-leaf secondary structure and the remaining tRNAs lacked the DHU arm, TψC arm or both. Moreover, a comparative analysis of all reported scale insect mitogenomes from GenBank database was performed. The mitogenomes of scale insects showed high similarities in base composition and A+T content. Additionally, our phylogenetic analysis confirmed the monophyly of Coccomorpha and revealed that the archaeococcoids were the most basal lineage within Coccomorpha, while Ericeruspela and Didesmococcuskoreanus, belonging to Coccidae, were often mixed with Aclerdidae, making Coccidae a paraphyletic group. These findings expand the mitogenome database of scale insects and provide new insights on mitogenome evolution for future studies across different insect groups.
ABSTRACT
Creophilus Leach and Platydracus Thomson are two genera whose members were formerly included in a poorly defined Staphylinus. Both include large-sized rove beetles that can be frequently found in carrion, faeces, and other such rotting materials worldwide. But there are not yet mitochondrial genomes in public databases, which deters scientists from further studies that involve species of these two genera. Here we present the first complete mitochondrial genomes of two typical Palaearctic species, Creophilus maxillosus and Platydracus impotens, which are also the first for the two genera. Additionally, we included the new mitogenomic data in a phylogenetic context using maximum likelihood phylogenetic analyses. Our results confirm the results of previous studies but show that the position of Creophilus, and therefore the monophyly of Staphylinina, could be affected by dataset constitution and model selection.
Subject(s)
Coleoptera , Genome, Mitochondrial , Animals , Coleoptera/genetics , PhylogenyABSTRACT
Scaphidium is a rove beetle genus (Coleoptera: Staphylinidae) of remarkable and diverse colouration. Although most of Scaphidium species are easily distinguished by the colour patterns, there exist some confusing variants, which may introduce bias into rapid identification. Molecular identification using the mitochondrial genome is a reliable approach that overcomes the shortcoming of morphological recognition for those who have limited experience in species-level identification. Here we described the nearly complete mitochondrial genome of Scaphidium formosanum Pic, 1915, a species with variant colour types, and tested the reliability of identification based on mitochondrial genes by both gene-wise metrics and phylogenetic analyses. In this study, the 17,455 bp mitochondrial genome of S. formosanum is composed of 13 protein-coding genes (PCGs), 22 tRNAs, and 2 rRNAs. All PCGs start with typical ATN codons, except Nad4l which began with the TTG codon. The gene order is consistent with the typical linear arrangement of the published rove beetle mitochondrial genomes. The nucleotide composition is highly A+T biased (76.42%): A - 39.99%, T - 36.44%, C - 15.08%, and G - 8.49%. Multiple metrics support that our sample has a higher similarity to S. quadrimaculatum than to other species. Maximum likelihood trees confirm the placement of our sample as the closest related entity to S. quadrimaculatum. We conclude that the mitochondrial genome has a reliable performance in molecular identification in this case.
