Branchiostegal Membrane Research Articles

A new freshwater gobiid species of Rhinogobius Gill, 1859 (Teleostei: Gobiidae) from northern Taiwan

A new freshwater rhinogoby has been collected and surveyed from northern Taiwan. The new species, Rhinogobius yangminshanensis n. sp. with fluvial life history can be well distinguished from other congeners by the following combination of features: (1) fin rays: second dorsal fin rays I/9; anal fin rays I/8; pectoral fin rays modally 16; (2) squamation: longitudinal scale series 28-30 (modally 29); perdorsal scales 9-10 (modally 9); (4) vertebral count 27; (5) rear edge of mouth: merely extending to vertical of anterior margin of pupil in male and (6) specific colouration: lateral side with 6-7 longitudinal rows of bright orange to orange red spots in male which general size about 1/2 of pupil diameter. Cheek and opercle with 24-35 orange spots in male. Branchiostegal membrane with many minute orange spots in male. Caudal fin with distally orange zone in male with about 3 vertical rows of orange or orange red spots. First dorsal fin with broad orange band on distally 1/3 area. A middle black spot in abterior first dorsal fin. Pectoral fin with two rows red orange spots in male. The phylogenetic comparisons have revealed that the great mitogenetic differences of R. yangminshanensis with all other congeneric species and sister species would be R. rubromaculatus in Taiwan. A diagnostic key to all valid species of Rhinogobius from Taiwan is also provided.

The Pandemic Blenny, Coralliozetus clausus, a new species of tube blenny endemic to Isla del Coco, Costa Rica (Teleostei: Chaenopsidae).

Coralliozetus clausus, a new species of chaenopsid blenny, endemic to Isla del Coco, Costa Rica, is described. This small species, not exceeding 15 mm SL, is a short-bodied member of the genus along with Coralliozetus cardonae (Caribbean), Coralliozetus angelicus, and Coralliozetus springeri (both eastern Pacific). It differs from its closest relative, C. springeri, known from mainland waters from Costa Rica to Ecuador, in having a single tiny supraorbital cirrus and dark dots on the operculum and branchiostegal membrane of males while C. springeri has paired supraorbital cirri (one of which is substantial in size) and no dots on the operculum. Although two other species of Coralliozetus have been reported from Isla del Coco, this appears to be only member of the genus present on the island. It is the second chaenopsid endemic to Isla del Coco and brings the number of cryptobenthic fishes endemic to Isla del Coco to twelve.

Ontogenic Development Of Gills In Pre To Post-Flexion Stages Larvae Of Himalayan Snow Trout Schizothorax Plagiostomus (Heckel)

The ontogenic development of gills, including gill arch, gill filaments, and gill rakers in pre to postflexion stages larvae of Himalayan Snow Trout Schizothorax plagiostomus were studied with the objectives that this study could serve as a base for further studies about the early embryonic development and organogenesis in various fish species inhabiting hill stream environments. To obtain the pre to post-flexion stages larvae, an artificial breeding experiment was conducted during September- October on the bank of snow-fed river Alaknanda by stripping method. Further, the development of the gill apparatus was studied histologically, using light microscopy. Hatchling takes place 124-130 hours after fertilization at the incubation temperature of 19-200C. On second dph (day post-hatching), gill arches, gill filaments, and branchiostegal membrane began to differentiate. By the third dph, blood channels were observed in gill filaments as well as in pseudobranch. Formation of secondary lamellae, branchial arteries, elongation of the gill cover, cartilaginous rod formation in the gill arch, and the branchiostegal membrane was discernible by fourth-fifth dph. Pillar cells and afferent and efferent arteries with RBCs in primary and secondary lamellae were observed on the seventh dph. Around the onset of exclusive exogenous feeding (twelfth dph), gill rakers and a group of pillar cells with blood channels were recognizable. Well-organized and functional gill structures with increased number and size of secondary gill lamellae were present among the fifteenth-seventeenth dph larvae. The general pattern of structural and functional development of both the natural site and laboratory-reared larvae was similar, except a large amount of mucous and clustered epithelial cells among the laboratory-reared larvae, which may be due to the physiological as well as environmental stress posed by the adverse physicochemical conditions.

A new species of Corcyrogobius (Teleostei: Gobiidae) from Île de Ngor, Senegal.

Corcyrogobius pulcher sp. nov. is described from off Île de Ngor, Dakar, Senegal. Corcyrogobius pulcher is distinguished from its two congeners by having the rear edge of the jaws ending posteriorly below mideye, second dorsal fin I/9, pectoral fin rays 17, pelvic fins oval or truncated posteriorly, scales in lateral series 26-27, anterior oculoscapular head canal with pore β, suborbital row b of sensory papillae anteriorly beginning below vertical of posterior edge of eye, dark vertical caudal bar, branchiostegal membrane without intense dark spot, cheek with two oblique whitish stripes, the first going from the eye downwards and forward to the posterior jaws, the second on the preopercular, alternating with brown oblique stripe going from behind the eye downwards and forward across the cheek. Furthermore, mitochondrial COI-barcoding data unambiguously support the species-level distinctiveness of the three Corcyrogobius species. A key to the species of Corcyrogobius is provided.

Larval development of Brycon amazonicus (Teleostei, Bryconidae) with a focus on locomotory, respiratory and feeding structures.

In the present work we describe the larval development of Brycon amazonicus, with emphasis on structures linked to swimming, respiration and feeding. We monitored from larval hatching (13 h post-fertilization) to juvenile stage. Formation of the oral cavity and differentiation of gill arches began within 4 h post-hatching (hph) and within 11 hph the primordium of the pectoral fin appeared. At 25 hph, the head was in a rectilinear position with a terminal mouth, when the onset of tooth formation appeared. At 35 hph, gill arches were covered by the operculum and branchiostegal membrane and cusps of teeth pierced the epithelium of the premaxilla and anterior dentary region. Sharp teeth were observed in the maxilla at 171 hph and the pelvic fin primordium appeared at 243 hph, with taste buds on the tongue and the roof of the buccopharyngeal cavity. At 579 hph, all structures related to swimming and food capture were formed. Exogenous feeding of the larvae started at 29 hph, before the endogenous reserves were used up and the development of efficient swimming ability, reflecting the species' need to increasingly specialize on prey capture.

Description of four new species of freshwater gobies from the Black River drainage in China and Vietnam (Teleostei: Gobiidae).

Four new species of Rhinogobius Gill 1859 are described from the Black River drainage in China and Vietnam. Rhinogobius coccinella, new species, and R. nanophyllum, new species, are described from the Mengyejiang River in Yunnan, China. Rhinogobius coccinella is diagnosed by having the cheek and operculum with about 25 large dark spots and branchiostegal membrane unmarked; caudal-peduncle depth 11-12% SL; 1-5 predorsal scales; 27-30 midlateral scales; and 28 vertebrae. Rhinogobius nanophyllum is diagnosed by having the cheek, operculum and pectoral-fin base with about 90 indistinct white marks, caudal fin plain-colored, second dorsal fin magnified with a very broad dark gray median band and a broad white proximal band in males; caudal-peduncle length 22-25% SL and pectoral-fin length 21-24% SL in males; head width at operculum 53-58% HL in males, 58-61% HL in females; 0 predorsal scales; 8-10 branched rays in the second dorsal fin; 7-8 branched anal-fin rays; and 28 vertebrae. Rhinogobius ngutinhoceps, new species, is described from the Nam Na River in Lai Chau, Vietnam. It differs from all congeners by the presence of a supraotic pore β; cheek and operculum with about 65 dark marks and branchiostegal membrane unmarked in males; snout pointed; lower jaw conspicuously protruding; predorsal length 40-41% SL; 12-15 predorsal scales; and 29 vertebrae. Rhinogobius phuongae, new species, is described from the Nam Mu River in Lai Chau, Vietnam, and is diagnosed by having the cheek with about 25 indistinct dark spots and branchiostegal membrane with pale spots in males; operculum unmarked; flank plain-colored in males; a conspicuous black blotch between spines I and III of the first dorsal fin; unpaired fins with a very broad white distal band; pectoral-fin length 20-21% SL; 8-10 predorsal scales; 8-9 branched rays in the second dorsal fin; and 28 vertebrae. A key to the species of Rhinogobius occurring within the Red River drainage is given.

A new species of Rhinogobius (Pisces: Gobiidae), with analyses of its DNA barcode

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.

Rhinogobius immaculatus, a new species of freshwater goby (Teleostei: Gobiidae) from the Qiantang River, China.

A new freshwater goby, Rhinogobius immaculatus sp. nov., is described here from the Qiantang River in China. It is distinguished from all congeners by the following combination of characters: second dorsal-fin rays I, 7–9; anal-fin rays I, 6–8; pectoral-fin rays 14–15; longitudinal scales 29–31; transverse scales 7–9; predorsal scales 2–5; vertebrae 27 (rarely 28); preopercular canal absent or with two pores; a red oblique stripe below eye in males; branchiostegal membrane mostly reddish-orange, with 3–6 irregular discrete or connected red blotches on posterior branchiostegal membrane and lower operculum in males; caudal-fin base with a median black spot; and no black blotch on anterior part of first dorsal fin in males.

A new species of Rhinogobius (Teleostei: Gobiidae) from Zhejiang Province, China

A new freshwater goby, Rhinogobius niger, was collected from Zhejiang Province, Southern China. This species can be distinguished from all congeners by a combination of the following features: second dorsal fin rays modally I/9, anal fin rays I/8, pectoral fin rays 16–18, longitudinal scale series 35–37, transverse scale series 10–12, predorsal scale series modally 0, vertebral counts modally 10 + 17 = 27, head and body blackish in male, cheek without any stripe or spot, the upper margin of the preoperculum with two horizontally aligned reddish brown stripes running backwardly, branchiostegal membrane with 15–25 small reddish orange round spots in adult male, first dorsal fin with a large black blotch anteriorly. A diagnostic key to all nominal species of Rhinogobius with high vertebral count (27–29) from mainland southeastern Asia, China, Japan and Taiwan is also provided.

Evolution of the branchiostegal membrane and restricted gill openings in Actinopterygian fishes.

A phylogenetic survey is a powerful approach for investigating the evolutionary history of a morphological characteristic that has evolved numerous times without obvious functional implications. Restricted gill openings, an extreme modification of the branchiostegal membrane, are an example of such a characteristic. We examine the evolution of branchiostegal membrane morphology and highlight convergent evolution of restricted gill openings. We surveyed specimens from 433 families of actinopterygians for branchiostegal membrane morphology and measured head and body dimensions. We inferred a relaxed molecular clock phylogeny with branch length estimates based on nine nuclear genes sampled from 285 species that include all major lineages of Actinopterygii. We calculated marginal state reconstructions of four branchiostegal membrane conditions and found that restricted gill openings have evolved independently in at least 11 major actinopterygian clades, and the total number of independent origins of the trait is likely much higher. A principal component analysis revealed that fishes with restricted gill openings occupy a larger morphospace, as defined by our linear measurements, than do fishes with nonrestricted openings. We used a decision tree analysis of ecological data to determine if restricted gill openings are linked to certain environments. We found that fishes with restricted gill openings repeatedly occur under a variety of ecological conditions, although they are rare in open-ocean pelagic environments. We also tested seven ratios for their utility in distinguishing between fishes with and without restricted gill openings, and we propose a simple metric for quantifying restricted gill openings (RGO), defined as a ratio of the distance from the ventral midline to the gill opening relative to half the circumference of the head. Functional explanations for this specialized morphology likely differ within each clade, but its repeated evolution indicates a need for a better understanding of diversity of ventilatory morphology among fishes. J. Morphol. 276:681-694, 2015. © 2015 Wiley Periodicals, Inc.

First Record of the Eyeshade Sculpin Nautichthys pribilovius (Hemitripteridae: Pisces) from the East Sea, Korea

A new record of the eyeshade sculpin Nautichthys pribilovius is described on the basis of a single specimen collected from the East Sea, Korea. The species has 23 second dorsal fin rays, rounded spines on the occiput, a black band through the eye and across the cheek, branched caudal fin rays and a branchiostegal membrane attached to the isthmus. The new Korean name Gum-eun-tti-nun-hoet-dae-sok is proposed for the genus Nautichthys, and Gum-eun-tti-nun-hoet-dae is proposed for the species N. pribilovius.

A new genus and species of hatschekiid copepod (Siphonostomatoida) from groupers (Actinopterygii: Serranidae) collected off the Ryukyu Archipelago, Japan

A new genus and species of copepod, Mihbaicola sakamakii n. g., n. sp., belonging to the siphonostomatoid family Hatschekiidae, is described based on the females collected from inside the tissue of the branchiostegal membrane in three species of the groupers, Epinephelus fasciatus (Forsskål) (type-host), E. merra Bloch and Cephalopholis leopardus (Lacépède), collected off Okinawa-jima Island and Iriomote-jima Island, Ryukyu Archipelago, North Pacific Ocean. The new genus can be distinguished from other hatschekiid genera by a combination of the following characters in the female: the head is composed of the cephalosome and the pedigerous somite; the cephalothorax is expanded into a pair of posteroventral lobes carrying leg 1; legs 1 and 2 are biramous and composed of the protopod and both rami are 2-segmented; leg 3 is absent; and leg 4 is represented by a rounded lobe with a chitinous pointed apical process.

<I>Rhinogobius zhoui</I>，a New Goby (Perciformes: Gobiidae) from Guangdong Province, China

A new freshwater goby, Rhinogobius zhoui sp. nov., was found in the stream of Lianhua Mountain（23º01'N，115º17'E）in Haifeng County, Guangdong Province, China. The new species can be distinguished from related species by combination of characters: second dorsal fin rays I, 8-9; anal fin rays I, 7-8; pectoral fin rays 16—18; longitudinal scale series 29-31; predorsal scales 10-12; vertebral count 10+16=26; In adult male, first dorsal fin without black spot, each median fin with broad white band, cheek and branchiostegal membrane unpigmented, 6-;8 red blotches on body side.

<I>Rhinogobius zhoui</I>，a New Goby (Perciformes: Gobiidae) from Guangdong Province, China

A new freshwater goby, Rhinogobius zhoui sp. nov., was found in the stream of Lianhua Mountain（23º01'N，115º17'E）in Haifeng County, Guangdong Province, China. The new species can be distinguished from related species by combination of characters: second dorsal fin rays I, 8-9; anal fin rays I, 7-8; pectoral fin rays 16—18; longitudinal scale series 29-31; predorsal scales 10-12; vertebral count 10+16=26; In adult male, first dorsal fin without black spot, each median fin with broad white band, cheek and branchiostegal membrane unpigmented, 6-;8 red blotches on body side.

New species of Achirus (Pleuronectiformes: Achiridae) from Northeastern Brazil

Eight species are considered valid in the genus Achirus (Lacépède), distributed on both sides of the Americas, mainly in marine and estuarine waters with A. novoae being the only species of this genus restricted to freshwaters of the Orinoco basin and its delta. A new species, A. mucuri, is described from the estuary of the Mucuri River, a small system in Bahia state, northeastern Brazil. A. mucuri differs from congeners, except A. novoae, in having a connection between the branchiostegal membrane and the isthmus. A. mucuri differs from A. novoae in its labial fimbriae and latero-sensory cephalic canal pattern.

Physical model of the development of external signs of barotrauma in Pacific rockfish

Four species of Sebastes (Pacific rockfish) showed evidence of a wide array of internal injuries from capture-induced barotrauma, including liver and swimbladder damage, organ displace- ment related to esophageal eversion, and hemorrhage in the pericardium and abdominal cavity. However, clear evidence of swimbladder rupture was not observed in all fish with external signs of barotrauma. Injection of air through the body wall into the swimbladders of rockfish carcasses gen- erated all of the common external signs of barotrauma documented in wild-captured fish, suggesting that the physical effects of swimbladder gas expansion can create these gross external signs without embolism from dissolved blood gases. Dissections of injected black rockfish S. melanops carcasses showed that, typically, injected air escaped the swimbladder without obvious rupture, moving in an anterio-dorsal direction, generating bulges and air bubbles that were externally visible through the branchiostegal membrane. Injected air also collected dorsally to the esophagus, posterior to the pha- ryngeal teeth, causing the esophagus to roll outwards into the buccal cavity (esophageal eversion). Injected air also frequently traveled further forward, collecting medially to the eyeball, leading to exophthalmia, and then moved distally along the fascia, invading the corneal stroma from the edges, resulting in corneal emphysemas. Air injected into the swimbladders of quillback rockfish S. maliger carcasses generated similar eye effects, but also escaped through ruptures in the branchiostegal membrane and did not generate esophageal eversion, which is also infrequent in wild-caught speci- mens. These results demonstrate that the major external signs of barotrauma in Pacific rockfish can develop as result of escaping swimbladder gases following an internal 'path of least resistance'.

A new species of Rhinogobius (Teleostei: Gobiidae) from the Hanjiang Basin in Guangdong Province, China

A new freshwater goby, Rhinogobius wangi, was collected from a small tributary of the Hanjiang Basin, Guangdong Province, southeastern China. The species can be distinguished from all congeneric species by the following unique combination of features: second dorsal fin rays I, 8; anal fin rays I, 7; pectoral fin rays 16; rather large scales as longitudinal scale series 26–27; predorsal scales 8–9; vertebral count 10 + 17 = 27; seven parallel, deep brown oblique stripes crossing on cheek in male; branchiostegal membrane with brownish-red spots in male; seven longitudinal deep brown lines on lateral side of body; pectoral fin base with a blackish-brown bar. A key to all nominal species with high vertebral counts from China (Hanjiang to Chiangtangjiang basins), Taiwan, and Japan is also provided.

Porocottus leptosomus sp. nov., from the west coast of Korea, Yellow Sea (Scorpaeniformes: Cottidae)

A new cottid species, Porocottus leptosomus, is described on the basis of 12 specimens collected from Taean, west coast of Korea, Yellow Sea. The species is distinguished from other species of Porocottus by the following combination of characters: a strongly compressed body, two pairs of branched cirri on the dorsal surface of the head, bases of head cirri smooth, a single cirrus on the dorsal tip of each spine of the first dorsal fin, a single opening of the sixth canaliculus of the infraorbital sensory canal, a long posterior medial canaliculus of the occipital canal with the terminal pore and a few supplementary pores, and melanophores on the isthmus hidden beneath the branchiostegal membrane.

Ontogeny of the osteocranium in the African catfish, Clarias gariepinus Burchell (1822) (Siluriformes: Clariidae): Ossification sequence as a response to functional demands.

The ontogeny of the bony skull of the African catfish, Clarias gariepinus, is studied from initial ossification until a complete skull is formed. The ossification sequence in C. gariepinus seems to be related to the functional demands that arise in a developing larva. Early ossification of the opercular bone coincides with the initiation of opercular skin movements. Early ossifications involve several dentulous bones, formed shortly before the transition phase from endogenous to exogenous feeding. The enlarging branchiostegal membrane becomes supported by the gradual adding of branchiostegal rays. Parasphenoid ossification may be related to protection of the brain during prey transport, whereas the several hyoid bones, including the parurohyal, are formed in relation to the increasing loads exerted onto the tendons of the sternohyoideus and consequently onto the hyoid bar. Overall skull reinforcement occurs almost simultaneously, with a whole set of perichondral bones arising especially at places of high mechanical load. The suspensorium becomes protected against dislocation in an anteroposterior direction through a ligamentous connection, which even becomes partially ossified, forming the sesamoid entopterygoid. Later, the cranial lateral-line system becomes enclosed by a set of gutters, which close, frequently becoming plate-like later in ontogeny. The brain also becomes covered dorsally. Additional dentition (prevomeral tooth plates) formation seems to coincide with formation of the opercular four-bar system, as well as with the time the digestive system becomes completely functional. Eventually, unossified regions between the bones become closed off, fortifying and completely covering the skull. J. Morphol. 235:183-237, 1998. © 1998 Wiley-Liss, Inc.

Enrichment of live food with essential fatty acids and vitamin C: effects on milkfish ( Chanos chanos) larval performance

The effects of essential fatty acids (EFA) and vitamin C-enriched live food on growth, survival, resistance to salinity stress and incidence of deformity in milkfish larvae reared in tanks were investigated. Larvae were either fed rotifers cultured on Chlorella sp. and newly hatched Artemia nauplii (control), highly unsaturated fatty acid (HUFA)-enriched rotifers and Artemia nauplii or HUFA+vitamin C-enriched rotifers and Artemia nauplii. Milkfish growth in outdoor nursery ponds was also assessed to compare with growth in indoor tanks. Milkfish fed rotifers/ Artemia enriched with HUFA (32–48 mg dry weight, DW) or HUFA+vitamin C (33–45 mg DW) exhibited significantly ( P<0.05) higher growth than those given unenriched live food (24–27 mg DW) after 40 days of culture. Growth of milkfish in nursery ponds (albeit lower in stocking density) showed similar trends as those reared in tanks. When subjected to salinity stress (Day 25), mortality of the HUFA+vitamin C-treated fish and HUFA-treated fish were significantly lower ( P<0.05) than the control fish. Survival of 26-day old milkfish, however, did not differ significantly ( P>0.05) among the treatment groups. Forty-day-old milkfish fed HUFA+vitamin C-enriched live food had significantly lower ( P<0.05) incidence of opercular deformity (mainly cleft branchiostegal membrane) (8.4–14.7%) compared with those given HUFA-enriched (15.8–23.5%) or unenriched (27.3–33.5%) live food. Results demonstrated the effect of HUFA enrichment in enhancing milkfish larval growth and resistance to salinity stress but not overall survival. Moreover, HUFA and ascorbate supplementation decreased but did not totally eliminate incidence of opercular deformity in milkfish larvae.