The complete mitochondrial genome sequence of Oncicola luehei (Acanthocephala: Archiacanthocephala) and its phylogenetic position within Syndermata

The complete mitochondrial genome sequence of Southwellina hispida supports monophyly of Palaeacanthocephala (Acanthocephala: Polymorphida)

“…Within Syndermata, phylogenetic trees recovered monophyly of Monogononta, Bdelloidea (rotifer groups), and Acanthocephala, each receiving very strong branch support. Paraphyly of Eurotatoria (Bdelloidea and Monogononta) was also observed in this study, as already confirmed in earlier studies [10,11,19,22,37]. The asexual rotifer group Bdelloidea was recovered as sister to Acanthocephala.…”

“…As similar to other syndermatan species [10,36,37], the sense strand of S. hispida mtDNA showed nucleotide compositional bias toward T and against C. The overall A + T content of the entire genome is 63.9%. Higher T content (40.4% T) in 12 PCGs corresponds to relatively high frequency of T-rich codons: TTA for leucine (6.99%), GTT for valine (6.90%), TTT for phenylalanine (6.73%), and TTG for leucine (5.90%).…”

“…The nucleotide sequences obtained from these three partial gene fragments were used to design S. hispida-specific primers for long PCR amplification (Supplementary Table 1) and three overlapping long PCR products (approximately 1.8 kb, 5.5 kb, and 8 kb in size, respectively) were amplified by using three primer combinations (S_his_Cox1F/ S_his_16SR, S_his_CytbF/S_his_Cox1R and S_his_16SF/S_his _CytbR). Details of PCR amplification and sequencing have been described in a previous study [10].…”

“…KJ869251), and it is among the largest acanthocephalan mtDNA sequences reported so far [10,21,22,36]. The large genome size is ascribed to relatively lengthy intergenic sequences (total: 1867 bp) that contain three noncoding regions (NCR1-NCR3) with remarkable size (larger than 200 bp, respectively).…”

“…Based on sharing some morphological characters including the eponymous syncytial epidermis and sperm ultrastructure, Acanthocephala and Rotifera (wheel animals) were combined as a clade Syndermata [3]. Their close relationship has also been supported by some other morphological evidence [4][5][6] and different types of molecular data (SSU rDNA [7,8]; SSU + LSU rDNAs and mitochondrial cox1 [9]; mitochondrial genome [10]; transcriptome data [11]). Acanthocephala was initially recognized as a subgroup of the Aschelminthes and included two orders: Palaeacanthocephala and Archiacanthocephala [12].…”