Description of a large specimen of Paralepis elongata (Brauer, 1906) from Angola, southeastern Atlantic Ocean (Aulopiformes: Paralepididae).

The elongate barracudina, Paralepis elongata (Brauer, 1906), received limited attention in the past, with only a few individuals documented, mostly in publications focusing on the feeding habits of large predatory pelagic fishes. Furthermore, the taxonomic history of the species is complicated, with some earlier sources providing incorrect information that influenced subsequent works. As a result, the accurate distribution range of P. elongata remains uncertain. An adult male specimen of P. elongata, representing the largest known individual, is reported from off Angola, southeastern Atlantic. A detailed description is provided, and the literature records of the species are reviewed and discussed.

DNA mini-barcoding reveals the mislabeling rate of canned cat food in Taiwan.

Background: Domestic cats are important companion animals in modern society that live closely with their owners. Mislabeling of pet food can not only harm pets but also cause issues in areas such as religious beliefs and natural resource management. Currently, the cat food market is booming. However, despite the risk that mislabeling poses to cats and humans, few studies have focused on species misrepresentation in cat food products. Methods: To address this issue, we used DNA barcoding, a highly effective identification methodology that can be applied to even highly processed products. We targeted a short segment (~85 basepairs) of the mitochondrial 16S rRNA (16S) gene as a barcode and employed Sanger or next generation sequencing (NGS) to inspect 138 canned cat food products in the Taiwanese market. Results: We discovered that the majority of mislabeling incidents were related to replacement of tuna with other species. Moreover, our metabarcoding revealed that numerous undeclared ingredients were present in all examined canned products. One product contained CITES Appendix II-listed shortfin mako shark (Isurus oxyrinchus). Overall, we uncovered a mislabeling rate of at least 28.99%. To verify cases of mislabeling, an official standardized list of vernacular names, along with the corresponding scientific species names, as well as a dependable barcoding reference sequence database are necessary.

First case of a reversed Parabothus taiwanensis Amaoka & Shen, 1993 from Taiwan (Pleuronectiformes: Bothidae), with first evidence of situs inversus viscerum in bothid.

Background: Reversed condition is rarely found in most flatfishes in natural environment, except for some certain species. The mechanism controlling the reversals in flatfishes has been studied in some cultivated species, whereas some have only few cases for the entire family and remain unclear. Here, we report the first record of a dextral (reversed) specimen of Parabothus taiwanensis Amaoka & Shen, 1993 collected off southwestern Taiwan recently. It represents the second reversed case ever recorded in Bothidae. We aim to provide a detailed description of this dextral specimen and compared to the sinistral (normal) specimens collected from the vicinity. Methods: Specimens were fixed in 4% formaldehyde and transferred to 70% ethanol for preservation. Meristic and morphometric characters were examined for both dextral and sinistral specimens. Dissections were made on specimens to confirm the position of internal organs. Lastly, X-radiographs were taken to elucidate the osteological features. Results: As a result, no differences of both meristic and morphometric characters were observed between the dextral and sinistral specimens. Nevertheless, situs inversus viscerum is discovered in the dextral specimen for the first time in Bothidae and the sixth record within flatfishes.

New species of the eel genera Dysomma and Dysommina from Vietnam, South China Sea (Anguilliformes: Synaphobranchidae).

Two new cutthroat eel species are described from Vietnam. Dysomma intermedium sp. nov. has a relatively long trunk, being about half of head length and anal-fin origin more than twice pectoral-fin length behind the pectoral-fin tip; pectoral fin well developed; dorsal-fin origin over or slightly in front of base of pectoral fin; two intermaxillary teeth; four or five compound teeth on ethmovomer; single row of seven or eight teeth on lower jaw; total lateral-line pores 70-76; and 21 pre-anal and 118-124 total vertebrae. Dysommina brevis sp. nov. differs from congeners by having a trunk shorter than head length, its length 11.1%-11.8% TL; a short pre-anal length 24.6%-25.6% TL, eye diameter 11.8%-12.3% head length; three large and one or two small teeth on ethmovomer; and fewer teeth on the upper and lower jaws. In addition, a specimen representing the first record of Dysommina orientalis in Vietnamese water is documented.

Redescription of the hispidoberycid, Hispidoberyxambagiosus Kotlyar, 1981 from Taiwan, with comments on its morphology (Beryciformes, Stephanoberycoidei, Hispidoberycidae).

A rare spiny-scale pricklefish, Hispidoberyxambagiosus Kotlyar, 1981, is redescribed based on four specimens collected from Taiwan. Their sampling locality represents the northernmost record of the family, which extends the family's distribution from the eastern Indian Ocean and the South China Sea to northeastern Taiwan in the northwestern Pacific Ocean. A detailed description of these specimens and the first description of its sagittal otoliths are provided. In addition, the specimens are compared with other known specimens. Intraspecific variation of some morphological characters are discussed.

Foxn1 is not essential for T-cell development in teleosts.

In mammals, T-cell development depends on the activity of the Foxn1 transcription factor in the thymic epithelium; mutations in the vertebrate-specific Foxn1 gene are associated with profound T-cell lymphopenia and fatal immunodeficiency. Here, we examined the extent of T-cell development in teleosts lacking a functional foxn1 gene. In zebrafish carrying a deleterious internal deletion of foxn1, reduced but robust lymphopoietic activity is maintained in the mutant thymus. Moreover, pseudogenization or loss of foxn1 in the genomes of deep-sea anglerfishes is independent of the presence or absence of the canonical signatures of the T-cell lineage. Thus, in contrast to the situation in mammals, the teleost thymus can support foxn1-independent lymphopoiesis, most likely through the activity of the Foxn4, an ancient metazoan paralog of Foxn1. Our results imply that during the early stages of vertebrate evolution, genetic control of thymopoiesis was functionally redundant and thus robust; in mammals, the genetic network was reorganized to become uniquely dependent on the FOXN1 transcription factor.

New records of a rare gibberfish, Gibberichthyslatifrons (Stephanoberyciformes, Gibberichthyidae), from the South China Sea, with comments on morphological characters.

The gibberfish Gibberichthyslatifrons is recorded for the first time from southwestern Taiwan, northern South China Sea, based on the collection of seven adults and subadults from the Dong-gang fish market, Pingtung. These specimens represent the northernmost extent of the adult range of the species, and they fill a distributional gap in the western Pacific Ocean. Our findings suggest that a population of the species has become recently established in the region. Detailed descriptions, otolith morphology, and fresh coloration are provided with comments on the morphological characteristics of the genus.

Okamejei picta sp. nov., a new rajid skate from the South China Sea (Rajiformes: Rajidae).

A new species of Okamejei is described based on two adult males collected from deep waters in the South China Sea. The new species, Okamejei picta sp. nov., is readily distinguished from most other congeners in having densely scattered black spots on dorsal disc. Okamejei hollandi and O. mengae is quite similar to the new species by their spot patterns on dorsal disc, but the new species differs from the former by a combination of characters: a yellowish brown dorsal surface densely covered with small, circular to irregular-shaped black spots; blotches on dorsal disc indistinct; posterior ocellus absent; ventral disc white; disc length 45.0-47.7% TL; distance between cloaca to caudal-fin tip 53.6-55.1% TL; trunk centra 31; total basal radials 73-76, morphology of clasper terminal skeleton, and lacking component funnel at the clasper end.

Redescription of Lestidiops distans (Ege, 1953) and comments on Lestidiops cadenati (Maul, 1962) from the eastern Atlantic Ocean (Teleostei: Aulopiformes).

The paralepidid species Lestidiops distans (Ege, 1953) is redescribed on the basis of adult specimens collected from the eastern Atlantic Ocean. Observations on the holotype, a detailed description, and full data of the adults are provided. The complete lateral line running to the caudal fin base found in L. distans is a rare condition, with only some species in the family possessing this character. The distribution range of L. distans, from Senegal (14°N) to Namibia (22°S) along the coastline of the eastern Atlantic Ocean, is revised accordingly. Comments on a congener, Lestidiops cadenati (Maul, 1962), that co-occurs in the western Atlantic are provided.

New records of two roughy fish species of Hoplostethus and a confirmed record of H.crassispinus Kotlyar, 1980 (Trachichthyiformes, Trachichthyidae) from Taiwan.

Two rarely caught species of the roughy fish genus Hoplostethus have been identified for the first time in the fish collections of Taiwan. The first, H.grandperrini Roberts & Gomon, 2012 was previously known only from two type specimens collected in the Southern Hemisphere off the coast of New Caledonia. Its distribution is now extended to the Northern Hemisphere off the coast of Pingtung, southern Taiwan. Our specimen represents the only record of this species since its initial description. The second, H.robustispinus Moore & Dodd, 2010 was originally described from a single specimen collected in the Philippines and was only known from the type locality and a single record off the Paracel Islands, South China Sea. This specimen represents the third record of the species since its original description. A single specimen of H.crassispinus Kotlyar, 1980, whose name has long appeared in the ichthyological literature of Taiwan and adjacent areas, was also identified as the first specimen-based record for Taiwan. Detailed descriptions of these species are provided and compared with available data of respective type specimens and related species, with intraspecific variations also discussed. Also included is a dichotomous key to all known species of the subgenus Hoplostethus in Taiwan.

Adult morphology and redescription of Lestidiopsindopacificus (Ege, 1953), with comments on the features of related species (Teleostei, Aulopiformes, Paralepididae).

Two specimens representing the first known adults of Lestidiopsindopacificus (Ege, 1953) are reported and described from Taiwan, and the validity and generic assignment of this species are confirmed. The origin of the pelvic fin directly below the dorsal-fin base shows that L.indopacificus belongs to the L.mirabilis species complex. It can be separated from its congeners by the position of the nostrils above the posterior end of the maxilla, the light body color with unevenly distributed melanophores in adults, and a distinct combination of meristic values and other morphological characteristics. New geographic records are reported for the two other current members of this species complex, L.mirabilis (Ege, 1933) and L.extremus (Ege, 1953). The diagnostic features that separate these three very similar species are discussed.

Record of the Amarsipa fish (Family Amarsipidae) from Pratas Island, South China Sea.

Two specimens of the rare Amarsipa fish, Amarsipus carlsbergi, were collected from Pratas Island in the northern South China Sea. They represent the first record of Taiwanese EEZ and fill the distribution gap in the northwestern Pacific Ocean between Japan (East China Sea) and Vietnam. The two specimens were identified based on their diagnostic characteristics, including no pharyngeal sacs, a pelvic fin well in front of the pectoral fin, a slender body and other morphology. Detailed data and descriptions of these two specimens, including a description of otolith morphology, are provided.

A new species of the shortnose batfish genus Halicmetus from Madagascar (Family Ogcocephalidae).

A new species of the batfish genus Halicmetus is herein described as unique, having a body densely covered with variously sized bucklers. It is also distinguished from congeners by the following combination of characters: body disk relatively small, disk width 59.7% SL; orbit small, its diameter 8.3% SL; interorbital moderately wide, 7.4% SL; tail length 47.7% SL; illicial trough opening wide and high; dorsal fin absent; pectoral-fin rays 13; uniformly creamy white when preserved; peritoneal membrane pale with dense melanophores and scattered black dots.

Hoplostethus roseus, a new roughy fish from the western Pacific based on morphology and DNA barcoding (family Trachichthyidae).

A new species of the roughy fish genus Hoplostethus is described from 11 types and a non-type specimen collected from Taiwanese waters. It can be distinguished from its congeners by a combination of characters: pectoral-fin rays 14-17 (modally 15-16); pyloric caeca 65-84; total gill rakers 19-20; predorsal scales 18-22; oral cavity, branchial chamber, top and underside of tongue, and peritoneum uniformly black; distal margin of membrane between dorsal-fin spines black; caudal fin without a black margin; caudal-fin base brownish. Comparisons of the new species with similar species are provided. DNA barcoding supports the monophyly of the new species, which appears to be closely related to Hoplostethus japonicus [average cytochrome c oxidase subunit I Kimura-2-parameter (COI K2P) distance of 4.1%].

Redescription of Parapercis moki Ho and Johnson, 2013 (family Pinguipedidae), with its first fresh coloration information.

Two specimens of Parapercis moki Ho Johnson were collected recently and detailed descriptions of their morphology and fresh coloration are provided. Its diagnosis is now revised as: band across head, six transverse bands on body and blade-like bar below eye; numerous small pores connected by canals forming about 910 vertical rows on cheek, opercle, and subopercle; scales on nape extending anteriorly to level of posterior margin of eyes; large spine on posteroventral corner of subopercle; very narrow interorbital space (1.72.0% SL); 4 dorsal-fin spines, each spine progressively longer, last spine entirely connected by membrane to first dorsal-fin ray; four pairs of canine teeth anteriorly in lower jaw; and palatine teeth present, in two rows, and vomerine teeth stout, in two rows.

A new Congrid eel, Rhynchoconger smithi sp. nov. (Anguilliformes: Congridae), from the Bay of Bengal, India.

A new Conger eel species is described based on four specimens collected from Petuaghat fishing harbour, West Bengal, India. The combination of morphological characters and molecular data are discordant with the seven congeners currently recognized. Rhynchoconger smithi sp. nov. can be distinguished by having head smaller than trunk; pre-anal length more than three times in total length; a small eye, diameter 2.0-2.2 in snout length; rictus ending at a vertical through posterior margin of pupil; ethmovomerine teeth patch small, with 58-74 blunt teeth arranged in seven to eight irregular rows; vomerine teeth patch small, with 18-28 granular teeth arranged in four to six irregular rows, distinctly separated by narrow spaces from the ethmovomerine and maxillary teeth; three supraorbital pores and one supra-temporal pore; and 159+ to 164 total vertebrae. Moreover, R. smithi differs significantly from four congeners, R. nitens, R. flavus, R. ectenurus and R. gracilior, with Kimura two-parameter (K2P) distances 14.6%-20.3%.

First adult record of the barracudina Lestidiops extremus (Ege, 1953), based on a specimen from the Philippines (Teleostei: Paralepididae).

The adult morphology of Lestidiops extremus (Ege, 1953), a barracudina originally described based on postlarvae from Indonesia, has long been a mystery. An adult specimen collected from off the Philippines represents the first confirmed record of an adult of this species. Observations on the holotype and a detailed description of the adult are provided. The location of the pelvic-fin origin in the adult, clearly behind the posterior end of the dorsal-fin base, is unique within this genus and the entire subfamily Lestidiinae. The present find extends the known range of the species from northwestern New Guinea, Indonesia, to seas east of the Philippines.

Engyprosopon keliaoense, a new lefteye flounder (Teleostei: Bothidae) from Taiwan.

A new bothid flounder, Engyprosopon keliaoense sp. nov., is described on the basis of 4 specimens collected from off southwestern Taiwan. The new species belongs to these congeners with a pair of black botches on the caudal fin and is most similar to E. grandisquama (Temminck & Schlegel). It can be separated from the latter by having smaller upper and lower eyes, narrower interorbital width, shorter pectoral fin on the ocular side, and more scales in the lateral line. Investigation on Rhombus grandisquama and its junior synonyms revealed that Rhombodoichthys spilurus Günther and Rhombus poecilurus Bleeker are retained as junior synonyms of E. grandisquama, whereas Rhombodoichthys spiniceps Macleay and Scaeops orbicularis Jordan & Seale are now excluded from the synonymy of E. grandisquama.