ABSTRACT
Here, we sequenced the complete mitogenome of Rhinogobius szechuanensis using the Illumina HiSeq platform and submitted the genome to Genbank with accession number OM617727. Assembly circular mitogenome (16,492 bp) consisted of 54.4% AT content, 13 protein-coding genes, 22 tRNA genes, two rRNA genes, an origin of light-strand replication, and a control region. Phylogenetic analysis supported that R. szechuanensis was grouped with R. rubromaculatus and clustered with other Rhinogobius species. The basal molecular data will be essential for further genetics studies such as evolution, taxonomy, DNA barcoding, and population genetics of Rhinogobius.
ABSTRACT
Sicyopterus garra Hora, 1925 from the insular streams of South Andaman Islands was synonymized with Sicyopterus microcephalus described from Java, South East Asia and has retained this taxonomic status since then. Recent collections of Sicyopterus from the type locality of S. garra and the examination of syntypes of this species revealed significant morphological and genetic differences from S. microcephalus and the other Sicyopterus species with papillae on upper lip. S. garra is thus a valid species and not a synonym of S. microcephalus. S. garra differs from S. microcephalus in having fewer lateral scales 53-59 vs. 57-68, fewer zigzag series (12-14 vs. 13-16), a longer caudal peduncle length (16-21 vs. 13-17), and by having a high percentage of divergence in COI gene (5.5%-5.8%).
Subject(s)
Cyprinidae , Perciformes , Animals , Cyprinidae/anatomy & histology , Perciformes/anatomy & histology , India , IslandsABSTRACT
The Korean trident goby, Tridentiger brevispinis, lives in adverse habitats that can easily become hypoxic due to low precipitation, regional dry periods, and high amounts of solar radiation. Histological and morphometric studies revealed the goby's specialized skin (35.4-150.0 µm in thickness), consisting of an epidermis and dermis. The thicker epidermis comprises an outermost surface layer (having taste buds, stratified flattened cells, mucous cells, pigment cells, and stratified polygonal cells), middle layer (having stratified polygonal cells), and stratum germinativum (stratified columnar cells). In particular, the dermis has scales, well-developed vascularization, and a few blood capillaries just above the basement membrane, and a reduced diffusion distance was present in the lateral body. Consequently, adaptations such as thicker epidermis, well-developed vascularization, few blood capillaries, and a reduced diffusion distance may provide cutaneous respiration for survival in poorly oxygenated water during the periodic dry season.
ABSTRACT
Rhinogobius similis is distributed in East and Southeast Asia. It is an amphidromous species found mostly in freshwater and sometimes brackish waters. We have obtained a high-resolution assembly of the R. similis genome using nanopore sequencing, high-throughput chromosome conformation capture (Hi-C), and transcriptomic data. The assembled genome was 890.10 Mb in size and 40.15% in GC content. Including 1373 contigs with contig N50 is 1.54 Mb, and scaffold N50 is 41.51 Mb. All of the 1373 contigs were anchored on 22 pairs of chromosomes. The BUSCO evaluation score was 93.02% indicating high quality of genome assembly. The repeat sequences accounted for 34.92% of the whole genome, with retroelements (30.13%), DNA transposons (1.64%), simple repeats (2.34%), and so forth. A total of 31,089 protein-coding genes were predicted in the genome and functionally annotated using Maker, of those genes, 26,893 (86.50%) were found in InterProScan5. There were 1910 gene families expanded in R. similis, 1171 gene families contracted and 170 gene families rapidly evolving. We have compared one rapidly change gene family (PF05970) commonly found in four species (Boleophthalmus pectinirostris, Neogobius melanostomus, Periophthalmus magnuspinnatus, and R. similis), which was found probably related to the lifespan of those species. During 400-10 Ka, the period of the Guxiang Ice Age, the population of R. similis decreased drastically, and then increased gradually following the last interglacial period. A high-resolution genome of R. similis should be useful to study taxonomy, biogeography, comparative genomics, and adaptive evolution of the most speciose freshwater goby genus, Rhinogobius.
Subject(s)
Genome , Gills , Animals , Chromosomes , Genomics , Humans , Molecular Sequence Annotation , PhylogenyABSTRACT
The genus Rhinogobius Gill 1859 is widely distributed in fresh waters along the Western Pacific coast of tropical and temperate Asia. A new species, Rhinogobius maxillivirgatus, is described from Anhui Province in Eastern China. This species can be differentiated from all congeners by a combination of the following characters: up to 6 longitudinal brown to black stripes along the side of the body; pectoral-fin rays modally 14; predorsal scale series 5-9; lateral scale series 28-30; transverse scale series 6-7; branchiostegal membrane with about 20 red round spots in males; and 2 black oblique stripes parallel along the upper jaw on the anterior portion of the cheek. Analyzing sequences of cytochrome c oxidase subunit I revealed that the new species is closely related to, but distinct, from Rhinogobius wuyanlingensis.
Subject(s)
Perciformes , Animal Distribution , Animals , Asia , China , DNA Barcoding, Taxonomic , MaleABSTRACT
In order to unravel the synonymy of Rhinogobius Gill 1859, a neotype for Rhinogobius carpenteri Seale 1910, type species of its oldest synonym, Tukugobius Herre 1927, is designated and described based on topotypic material. The genus Tukugobius is removed from the synonymy of Rhinogobius from which it is distinct in having a longitudinal cephalic lateralis system, a naked pectoral-fin base, the first dorsal fin supported by 7 pterygiophores, and the first pterygiophore of the second dorsal fin inserted in interneural space 9. Its type species further differs from other species of Philippine Tukugobius by the presence of a median naked strip along the belly.