Gill Opening Research Articles

A new species of short unpatterned moray eel (Anguilliformes: Muraenidae) from the northwestern Indian Ocean, including the Socotra Archipelago, with a redescription of Gymnothorax pseudoherrei Böhlke

A new species of short brown unpatterned moray eel, Gymnothorax. arabicus sp. nov., is described based on specimens collected from the northwestern Indian Ocean, including the Red Sea, Socotra Archipelago, and Arabian Gulf. The new species is characterized by having the dorsal-fin origin before the gill opening, two branchial pores, one or two median intermaxillary teeth, biserial maxillary teeth, total vertebrae 114–120, and a plain brown head and body with dark yellow color at the tip of the tail. The new species formerly has been confused with G. pseudoherrei but is distinguished from it by having slightly more total vertebrae (114–120 vs. 111–116), dark stripes on the throat and side of the head, and a larger maximum size (ca. 300 mm TL vs. ca. 200 mm TL). Gymnothorax pseudoherrei, currently known from the Maldives and Sri Lanka to the Philippines, Solomon Islands, and northern Australia, is redescribed in the present study. A comparison of the COI mtDNA in BOLD, in association with published phylogenetic evidence, confirms that G. arabicus and G. pseudoherrei form two separate genetic lineages, corroborating the morphological data.

Bashimyzon cheni, a new genus and species of sucker loach (Teleostei, Gastromyzontidae) from South China

Bashimyzon, new genus, is here established for Erromyzon damingshanensis, and a new species of the genus is described from the You-Jiang of the Pearl River (=Zhu-Jiang in mandarin Chinese) basin in Guangxi Province, South China. This new genus has a small gill opening above the pectoral-fin base and short pectoral fins extending backwards short of pelvic-fin insertions, both characters combined to separate it from all currently-recognized gastromyzontid genera except Erromyzon and Protomyzon, but differs from the two genera in having a larger gap between the posterior edge of eye and the vertical through the pectoral-fin insertion and very small fleshy lobes posterior to the maxillary-barbel bases. It is further distinct from its most similar genus Erromyzon in having a relatively larger gill opening, fewer branched pectoral-fin rays folded against body, and more posteriorly placed pectoral fins with a shorter fin base. Bashimyzon cheni, new species, and B. damingshanensis, the single congeneric species, differ in number of lateral-line pored scales, body coloration, and cephalic contour, and also in substantial genetic divergence.

Garra hexagonarostris, a new labeonine fish (Teleostei: Cyprinidae) from the Chindwin basin, Manipur, Northeast India, and a critical review on the taxonomic status of G. minimus, G. alticaputus, G. nigricauda, G. kimini, and G. tyao.

Garra hexagonarostris, a new member of the proboscis species group, is described from the Chakpi River of Chindwin basin in Manipur, India. The new species is distinguished by the following combination of characters: a prominent hexagon-shaped unilobed proboscis with five large-sized conical tubercles on anterior margin, and three or four medium-sized conical tubercles on anteroventral region; transverse lobe with 1335 small- to medium-sized conical tubercles; lateral surface of snout swollen with 818 small- to medium-sized conical tubercles; 3132 lateral-line scales including three pored scales on caudal fin; and a large arch-shaped black spot on each side of opercle, immediately anterior to upper angle of gill opening. The taxonomic status of several species of Garra from Arunachal Pradesh and Mizoram, is reviewed and accordingly Garra minimus is considered as a junior synonym of G. quadratirostris; G. nigricauda as a junior synonym of G. arunachalensis; G. alticaputus and G. kimini as junior synonyms of G. birostris; and G. tyao as a junior synonym of G. rakhinica.

Morphological and molecular evidences confirm a new species in Ophichthus (Anguilliformes: Ophichthidae) from the east coast of India

A new species of snake eel, Ophichthus suryai sp. nov., is discovered based on six specimens collected from three different estuarine ecosystems in Odisha, India. The new species can be distinguished from its closely allied congeners Ophichthus alleni, Ophichthus zophistius, and Ophichthus altipennis, and other members in this genus by having the dorsal fin origin (DFO) just above or slightly anterior to the gill opening, its unique vertebral count (7-8/45-47/142-142), and teeth patterns consisting of multiple rows on both maxilla and mandible. The distinctiveness of this new species is also supported at the molecular level by a strongly supported (bootstrap value >99%) monophyletic grouping of the mitochondrial DNA (mtDNA) Cytochrome Oxidase I (COI) gene sequences of the holotype and one paratype. The current study describes the morphometric and meristic characters and molecular phylogeny of Ophichthus suryai sp. nov.

Influence of bionics shark gills tunnel portal on the micro-pressure wave at the tunnel exit

In this study, the bionic principle is used to relieve the micro-pressure waves (MPWs) at the tunnel exit. A bionic shark gill tunnel portal with holes was studied, and the effects of the opening ratios and oblique cutting angles of the bionic shark gill opening tunnel portal on the initial compression wave (ICW) and MPW induced by a high-speed train (HST) passing through the tunnel are examined. The results show that when the opening ratio of the bionic shark gill tunnel portal is 24%, the highest mitigation effect on the ICW pressure gradient and MPW is observed. In addition, the high-pressure region of the ICW in the tunnel decreased with increasing opening ratio. The greatest mitigation effect on the ICW pressure gradient and MPW is obtained for the oblique cutting angle of the bionic hole on the tunnel portal (with an opening ratio of 24%) of 16°, because the oblique cutting angle facilitates the expulsion of the jet-stream from the bionic hole at the tunnel portal.

Morphological Deformities in Stingrays (Dasyatidae) from the Rameswaram Island, South India

The present study reports the deformities in two different species of stingrays Maculabatis bineeshi and Neotrygon kuhlii along the Rameswaram Island. The structural deformity was observed in M. bineeshi species that were collected from Pamban–Therkuvadi fish landing centre, which was the first to be recorded along the Indian coasts with rostral irregularity of the aperture from the anterior margin of the snout around the right margin of the disc from the first gill opening. In addition to the first record, vertebral column deformity was observed in N. kuhlii, which was collected from Kunthukal fish landing centre. The external morphological characteristics showed a curved tail that had vertebral column deformities with severe scoliosis–kyphosis–lordosis starting from the pectoral girdle to the tail region

Heterochrony and the evolution of the longjaw mudsucker (Gobiidae, Teleostei).

Although longjaw mudsucker (Gillichthys mirabilis, Gobiidae) has been studied extensively for its ability to occupy low-oxygen environments, few studies have addressed the evolution of its exceptionally elongated jaws that extend posteriorly beyond the gill opening in large adults. In this study, the ontogeny of the maxillae of G. mirabilis, Gillichthys seta, and the out-group species Eucyclogobius newberryi was studied within the heterochrony framework using digitized landmarks and caliper measurements. The results show that the maxilla of both species of Gillichthys evolved via acceleration (increased growth rate) and that of G. mirabilis via hypermorphosis (continued growth to a larger body size); two forms of peramorphosis. This is in contrast to earlier studies that concluded that G. seta is paedomorphic. We were unable to confirm an earlier hypothesis of sexual dimorphism in the jaw length of G. mirabilis. The evolution of the elongated jaws and associated large buccopharyngeal membrane in G. mirabilis is hypothesized to increase the surface area for gas exchange during aerial respiration and may also serve to amplify the aggressive gaping display as observed in other fishes.

Morphology of the Buccal and Opercular Sealing Apparatus in Mudskippers (Gobiidae: Oxudercinae)

Although possession of the large bucco-opercular cavity and its utilization in the feeding, breathing, egg brooding, and burrowing activities are quite obvious in mudskippers, the apparatus of this structure is little known. In the present study, we examined the anatomy of the bucco-opercular sealing apparatus of four oxudercine gobies, Oxuderces nexipinnis, Scartelaos histophorus, Boleophthalmus boddarti, and Periophthalmodon septemradiatus, showing different degrees of terrestriality. The results show that the morphological modifications including the short and restricted gill openings, the membranes on the gill opercular edge (except O. nexipinnis), and the developed hyohyoideus 3 could serve to seal the gill openings. The possible movement of the ceratohyal, the relative height of the urohyal, and the developed geniohyoideus could function to seal the mouth. Contraction of the hyohyoideus 1 to 3 could compress the opercular cavity generating strong mud spitting, whereas activation of the dilator opercula, levator opercula, and a portion of the geniohyoideus may serve to expand this cavity enable sucking mouthful of water at slow speed. These morphological modifications are presumable to facilitate vital activities of mudskippers as transition onto land.

A new species of the conger eel genus Macrocephenchelys from deep waters of the Arabian Sea.

A new species of the genus Macrocephenchelys is described herein based on a single specimen collected from the deep-sea trawl landing at Kalamukku fish landing centre, Kerala coast, Arabian Sea. The new species is distinguished by having a dorsal-fin origin behind the middle of pectoral fin, a larger head, shorter trunk, larger gill opening, dorsal surface of body with dark-brown colour and ventral surface of head and belly with numerous patches of melanophores before anus, vertebrae 14-30-151. The new species shares most of the characteristics with Macrocephenchelys brevirostris but differs from it by having a more anterior dorsal-fin origin (vs. over the tip or slightly behind the pectoral-fin tip), larger head [15.3% total length (TL) vs. 10.5%-13.9% TL, 53.2% pre-anal length (PAL) vs. 35.8%-47.6% PAL], shorter trunk length (13.6% TL vs. 14.4%-20.6% TL, 47.3% PAL vs. 52.4%-66.2% PAL); further it shows 7.9%-8.1% genetic divergence from the sequences of M. brevirostris.

Assessment of Swamp Eels’ (Monopterus albus) Diaspora and Presence at Remedios, Cervantes, Ilocos Sur

The Asian swamp eels (Monopterus albus) which is locally known as Kolukol have been found to be occupying the rice fields of Barangay Remedios, Cervantes, Ilocos Sur. Unfortunately, the diaspora and presence of these eels remain undocumented. In such context, this study was conducted to describe the diaspora and presence of these eels. Specifically, this study determined their characteristics, the farmers’ fishing activities, and the common Kolukol dishes as experienced and observed by the farmers. Through interviews with the farmers, the study revealed that Kolukols, which occupied an estimated 2,666-hectare of rice fields, have anguilliform body, do not have scales, slippery, no fins, with gill openings merged into single slit underneath the head, is red to brown with a sprinkling of dark flecks across their backs, have large mouths and small eyes, bloody when cut, and go out at night. The study also discovered that the farmers use machete, their hands, and spear to catch these eels. After one (1) or two (2) hours of fishing, they can bring home at least three (3) kilograms of Kolukol. With the caught Kolukols, the common dishes out of them are paksiw, tinuno, and prinito. Based on these findings, the study concludes that potential of Kolukol in food product development is yet to be explored. As such, studies should be conducted on developing products out of Kolukol.

A new short brown unpatterned moray eel (Anguilliformes, Muraenidae) from the southeast coast of India, Bay of Bengal

Gymnothorax tamilnaduensissp. nov., a new species of short brown unpatterned moray, is described, based on four specimens ranging from 272–487 mm total length collected from the trawl bycatch landings at Mudasalodai fish landing centre, off Cuddalore coast, Tamil Nadu, southeast coast of India. The new species is distinguished by the following combination of characters: origin of dorsal fin at middle of rictus and gill opening, anus just before mid-body, series of lines of small dark spots present on head and a single line of black spot-on mid-line of body, jaw pores with white rim, anal-fin margin whitish, 3 pre-dorsal vertebrae, 56–59 pre-anal vertebrae and 139–150 total vertebrae. The new species differs from its known Indian water congeners by having series of lines of small dark spots present on the head and a single line of black spots on the mid-line of the body (vs. absent in all the three congeners in India), serrated teeth (vs. smooth), jaw pores with white rim (vs. black to brown in others) and higher vertebral count (139–150 vs. 134–138 in others). Our morphological and molecular analyses show that the new species forms a distinct clade from its congeners and these data support the status as a new species.

Two new species of the snake eel genus Bascanichthys (Anguilliformes: Ophichthidae) from the northwestern Pacific.

Two new species of the elongate snake eel genus Bascanichthys are described from the northwestern Pacific. Bascanichthys kabeyawan sp. nov. is described based on a single specimen collected from estuary of southern Taiwan. It is characterized by having head 4.6% TL; tail 52.3% TL; body depth at gill opening 1.1% TL; predorsal-fin length 58.4% HL; snout length 10.9% HL; body bicolored, head without bands; lateral-line pores anterior to anus 104; vertebral formula 4-103-224. Bascanichthys ryukyuensis sp. nov. is described based on two specimens collected from the shallow water of Okinawa-jima Island, Ryukyu Islands of southern Japan. It is characterized by having head 3.7-4.3% TL; tail 43.3-44.2% TL; predorsal-fin length 40.7-45.4% HL; snout length 11.3-13.1% HL; body pale brown, head without distinct dark bands after preservation; lateral-line pores anterior to anus 114-118; total vertebrae 207-216, mean vertebral formula 2-116-212; and dorsal-fin origin before middle of head.

Influence of hook barbs on the “through-the-gill” hook removal method for deeply hooked Smallmouth Bass

Sustainable catch-and-release fisheries are based on the assumption that most fish survive an angling event. The adoption of best practices has become important to help mitigate post-release injury, behavioral impairment and mortality. However, in any catch-and-release fishery, a proportion of fish will become inadvertently deeply hooked (e.g., in the gullet) and numerous studies have shown this to be a major driver of mortality. Although available science suggests that cutting the line tends to yield better outcomes than removing hooks in the gullet, there has been interest within the angling community with removing hooks using the “through-the-gill” method where the hook shaft is turned outwards into the gill region and then the hook is removed by pulling anteriorly by gripping the outside bend of the hook. Here, we tested the efficacy of removing barbed and barbless hooks though the gill opening from experimentally deep-hooked Smallmouth Bass (Micropterus dolomieu) relative to leaving the hooks in place. Using a control group and four experimental treatment groups (barbed and removed through the gills; barbless and removed through gills; barbed and left in; barbless and left in), we evaluated handling time, presence of bleeding, incidence of gill or esophageal injury, reflex impairment, incidence of hook shedding (for the left in treatment groups), and survival across a 24-hour monitoring period. Collectively, our results suggested that when hooks were barbed and removed through the gills, fish condition and survival were lower. In addition, barbed hooks were more likely to cause bleeding, gill damage, esophageal tearing, and impair reflexes. When hook removal was done through the gills, the chances of all sublethal outcomes across all categories were more likely to occur. While short-term mortality was not statistically linked with any treatment group, the greatest percentage of mortality (24%) occurred for fish that had barbed hooks removed using the through-the-gill method. These data suggest that when anglers use barbed hooks and encounter a deeply hooked fish, cutting the line poses the least risk to the fish.

A new species of Ancistrus (Siluriformes: Loricariidae) from Tapajós and Xingu basins, Brazil

Abstract A new Ancistrus species is described from Tapajós and Xingu river basins. It is distinguished from its congeners by the singular body color pattern, consisting of dark vermiculated stripes almost all over the body, and also by combination of features as a narrow head, large internostril distance, and absence of rows of enlarged odontodes on the lateral plates. In addition, the new species is distinguished from congeners that inhabit the rio Tapajós basin by the presence of a fully-developed adipose fin (vs. adipose fin absent in Ancistrus parecis and A. tombador, and vestigial adipose fin or absent in A. krenakarore). It differs from A. ranunculus, also from the rio Xingu, by the color pattern, smaller body size, smaller gill opening, and narrower cleithral width. The new taxon adds a new record to the list of species shared among the Xingu and Tapajós basins.

Vanmaneniamarmorata, a new species of loach (Teleostei: Gastromyzontidae) from the middle Chang-Jiang Basin in Guizhou Province, south China.

BackgroundThe gastromyzontid genus Vanmanenia was established by Hora in 1932, based on the type species Vanmaneniastenosoma. The genus is a loach group adapted to running waters of streams from southern China, northern Vietnam and Laos. Currently, 19 valid species of the genus have been recognised. The northernmost distribution of the genus is the Yangtze River (= Chang-Jiang in Chinese) Basin and five species (V.maculata, V.intermedia, V.stenosoma, V.pseudostriata and V.gymnetrus) have been reported from the Basin.New informationVanmaneniamarmorata, a new hillstream species of loach, is here described from the middle Chang-Jiang Basin in Guizhou Province, south China. It is distinguished from its congeners by having a combination of the following characters: three triangular-shaped rostral lobules; postdorsal saddles wider than interspaces; a more backwards-placed anus (the vent to anal distance 30.5–36.9% of the pelvic to anal distance); a larger gill opening with its upper extremity reaching the level of the middle of the orbit; anal-fin base length 5.6–6.4% of SL; caudal-peduncle length 11.6–12.9% of SL; prepelvic length 51.1–53.4% of SL. Its validity is also affirmed by its distinct cyt b gene sequence divergence with all sampled congeners and its monophyly recovered in a cyt b gene-based phylogenetic analysis.

First reliable record of Liparis punctulatus (Scorpaeniformes: Liparidae) in Korea

A single specimen of Liparis punctulatus (30.9 mm standard length) belonging to the family Liparidae, was collected in the waters off Busan on 4 August, 2016. This species is characterized by a single pair of nostrils, unlike other Liparis species. It is distinguished from L. ochotensis by the numbers of dorsal, anal, pectoral fin rays and the location of the gill opening (above the pectoral fin in L. punctulatus vs. extending ventrally in front of the pectoral fin). In the molecular analysis, 514 bp of 16S rRNA gene of the specimen in this study were identical to that of L. punctulatus from NCBI GenBank (K2P distance < 0.002). This is the first record of the species in Korea based on a voucher specimen, and we follow the Korean name “Kko-ma-kkom-chi” for this species proposed by Myoung et al. and Kim et al.

A new arrowtooth eel of genus emMeadia/em (Synaphobranchidae: Ilyophinae) from Vietnam, South China Sea.

Meadia minor sp. nov., a scaless ilyophine eel, is described on the basis of 10 specimens collected from off Quy Nhon, central coast of Vietnam. It can be distinguished from its congeners in having a relatively long trunk (21.3-25.0% TL) which is longer than head length; a short and blunt snout (21.4-23.7% HL); gill opening close to pectoral-fin base; interbranchial space broad (20.7-26.2% HL); dorsal-fin origin above posterior third of pectoral fin; body depth 24-28 times in TL; total vertebrae 118-122; mean vertebral formula 7-33-121; and a small body size, reaching 330 mm TL. The generic status of the new species is discussed. Short descriptions of two congeners are provided.

A new species of the genus Cirrhimuraena (Anguilliformes: Ophichthidae) from the Bay of Bengal, India.

A new species of the genus Cirrhimuraena (Anguilliformes: Ophichthidae), Cirrhimuraena indica sp. nov., is described based on eight specimens collected from the Paradip (Odisha) and Petuaghat harbours (West Bengal) along the Bay of Bengal. The species is distinct in having the upper jaw fringed with 16-17 cirri before posterior nostril and 4-5 in between the anterior and posterior nostrils on the side; dorsal fin originates above the level of gill opening, predorsal length is 9.3-10.9 in total length; the head is relatively large, the length is 9.3-9.8 in total length; no infraorbital pores are observed between the nostrils; teeth are numerous, small, conical and in bands on each jaw; pores are present before the gill opening 10-11 and before anus 47-48; pectoral-fin length is 2.4-2.8 in head length; predorsal vertebrae are 8-10, pre-anal vertebrae 43-47 and total vertebrae 164-169. In the maximum likelihood tree analysis for COI gene, the new species belongs to the same clade as the other congener of Cirrhimuraena chinensis and is separated from the species morphologically and genetically.

Four new species of Careproctus (Cottoidei: Liparidae) from the deep-water vicinity of the southern Kuril Islands (Western North Pacific).

Four new species of Careproctus (Cottoidei: Liparidae) are described from the Bussol Strait (the deepest channel of the Kuril archipelago) and two neighboring abyssal basins of the Western North Pacific. Careproctus laperousei sp. nov. from the northern slope of the Kuril-Kamchatka Trench (depths of 4796-4803 m) has the following characters: vertebrae 57, pectoral-fin rays 26, principal caudal-fin rays 8 and pore pattern 2-6-7-1; it differs from the most similar congeners from the North Pacific in having a black peritoneum, short head (22.5 % of standard length, SL) and large disk (37.0 % of head length, lc). Careproctus brevipectoralis sp. nov. from the Kuril Basin of the Sea of Okhotsk (depths of 3301 m) has the following characters: vertebrae 55, pectoral-fin rays 26, caudal-fin rays 9, pore pattern 2-6-7-1 and peritoneum black; it differs from congeners by the absence of pleural ribs, deep and compressed leaf-like body (greatest depth 119 % lc, depth above anal-fin origin 113 % lc), small head (18 % SL), short pectoral fin (11 % SL) and cartilaginous-like tissue surrounding the dorsal fin. Careproctus pulcher sp. nov. and Careproctus globulus sp. nov., both having 46 vertebrae, are found on the Pacific side of the Bussol Strait at depths of 2350-2358 m. Careproctus pulcher sp. nov. is characterized by pectoral-fin rays 31-32, caudal-fin rays 10, pore pattern 2-6-7-1 and peritoneum pale; it differs from the most similar congeners in having a shorter head (25.5-26.3 % SL in adults) and gill opening reaching ventrally to 4th pectoral ray. Careproctus globulus sp. nov. has the following characters: pectoral-fin rays about 24, caudal-fin rays 8 and peritoneum black; it differs from other species in having a globular body, deep curve of vertebral column and pore pattern 2-5-6-1. Thus, based on these collections, the underwater sill of the Bussol Strait is inhabited by different species of Careproctus than the neighboring abyssal plains, Kuril-Kamchatka Trench and the Kuril Basin of the Sea of Okhotsk. Careproctus laperousei sp. nov. is the most deep-water Careproctus in the North Pacific.

Vanmanenia intermedia Fang, 1935, a valid hill-stream species of loach (Teleostei: Gastromyzontidae) from the middle Yangtze River basin, Southwest China.

Vanmanenia intermedia, which has long been synonymized with V. pingchowensis since 1980, is here revalidated using morphological characters and molecular evidences, and redescribed on the basis of topotypic specimens. This species is distinguished from all other congeneric species by the following combination of characters: triangular-shaped rostral lobules without secondary rostral barbels; distal edge of dorsal-fin slightly concave; no longitudinal black stripe on the flank; a longer snout (length 52.6-64.5 % of HL); a more backwards-placed anus (the vent to anal distance 34.7-46.1% of the pelvic to anal distance); a slender caudal peduncle (depth 9.1-11.3 % of SL); a longer anal-fin base (length 7.5-9.5 % of SL); and a smaller gill opening with its upper extremity closer to the level of the lower margin of the orbit. The validity of V. intermedia is also confirmed by its significant cyt b gene sequence divergence with all sampled congeneric species and its monophyly recovered in the cyt b gene-based phylogenetic analysis.