After four decades—Occurrence of the daggertooth pike conger, Muraenesox cinereus (Actinopterygii: Anguilliformes: Muraenesocidae), in the Mediterranean Sea

In October 2020, a single specimen of the daggertooth pike conger, Muraenesox cinereus (Forsskål, 1775), was caught by longline at a depth of 120 m, from the Mediterranean coast of Turkey. This species has been recorded from the Mediterranean for the second time after approximately four decades. This new finding shows that the distribution of the species has expanded.

After four decades—Occurrence of the daggertooth pike conger, Muraenesox cinereus (Actinopterygii: Anguilliformes: Muraenesocidae), in the Mediterranean Sea

In October 2020, a single specimen of the daggertooth pike conger, Muraenesox cinereus (Forsskål, 1775), was caught by longline at a depth of 120 m, from the Mediterranean coast of Turkey. This species has been recorded from the Mediterranean for the second time after approximately four decades. This new finding shows that the distribution of the species has expanded.

Length–weight relations for 14 fish species (Actinoptergii) from the coastal waters off Gwangyang Bay, South Korea

Length–weight relations were estimated for 14 fish species sampled from the coastal waters off the Gwangyang Bay in South Korea. The following species were studied: Okamejei kenojei (Müller et Henle, 1841); Muraenesox cinereus (Forsskål, 1775); Thryssa adelae (Rutter, 1897); Thryssa kammalensis (Bleeker, 1849); Tribolodon hakonensis (Günther, 1877); Inimicus japonicus (Cuvier, 1829); Chelidonichthys spinosus (McClelland, 1844); Jaydia lineata (Temminck et Schlegel, 1842); Sillago japonica Temminck et Schlegel, 1843; Pholis nebulosa (Temminck et Schlegel, 1845); Favonigobius gymnauchen (Bleeker, 1860); Pampus echinogaster (Basilewsky, 1855); Cynoglossus joyneri Günther, 1878; Takifugu niphobles (Jordan et Snyder, 1901).The length–weight relation of Thryssa adelae (Rutter, 1897), (Engraulidae) has not been previously reported. The new maximum total length of Thryssa kammalensis (18.0 cm) is now provided. The values of coefficient a ranged from 0.0007 to 0.0218, and the values of exponent b ranged from 2.82 to 3.52.

Novel gene rearrangement in the mitochondrial genome of Muraenesox cinereus and the phylogenetic relationship of Anguilliformes

The structure and gene sequence of the fish mitochondrial genome are generally considered to be conservative. However, two types of gene arrangements are found in the mitochondrial genome of Anguilliformes. In this paper, we report a complete mitogenome of Muraenesox cinereus (Anguilliformes: Muraenesocidae) with rearrangement phenomenon. The total length of the M. cinereus mitogenome was 17,673 bp, and it contained 13 protein-coding genes, two ribosomal RNAs, 22 transfer RNA genes, and two identical control regions (CRs). The mitochondrial genome of M. cinereus was obviously rearranged compared with the mitochondria of typical vertebrates. The genes ND6 and the conjoint trnE were translocated to the location between trnT and trnP, and one of the duplicated CR was translocated to the upstream of the ND6. The tandem duplication and random loss is most suitable for explaining this mitochondrial gene rearrangement. The Anguilliformes phylogenetic tree constructed based on the whole mitochondrial genome well supports Congridae non-monophyly. These results provide a basis for the future Anguilliformes mitochondrial gene arrangement characteristics and further phylogenetic research.