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Freshwater habitats in Indo-Pacific tropical islands are mainly inhabited by amphidromous fish, which display a marine larval phase while the rest of their life cycle takes place in rivers. Gobiidae are the most diversified fish component in these ecosystems. In this study, we focused on the status of the widespread Stenogobius genus (Gobioidei). This genus, composed of 28 presumably valid species, is distributed from the Indian Ocean to French Polynesia. This paper focuses on the revision of the Stenogobius genus based on 318 specimens, including morphomeristic data and mitochondrial COI sequences. Our results show that there is one main widespread species, Stenogobius genivittatus (Valenciennes, 1837), found in the Indo-Pacific area from the South African East coast to East Pacific locations. We redescribe this species and we state on 12 species names as synonyms of S. genivittatus.

International audience; Three specimens of Hippichthys albomaculosus Jenkins and Mailautoka, 2010, only known from Fiji, were recently collected from the North Province of New Caledonia. Morphomeristic values confirm the identity of specimens. This study constitutes the first record of this species in New Caledonia and outside of its type locality.; Trois spécimens d'Hippichthys albomaculosus Jenkins & Mailautoka, 2010, connu uniquement des Fidji, ont été récemment collectés dans la province Nord de la Nouvelle-Calédonie. Les valeurs morpho-méristiques confirment l'identité des spécimens. Cette étude constitue le premier signalement de cette espèce en Nouvelle-Calédonie et hors de sa localité type.

International audience

A new species of Coelonotus, a freshwater pipefish, is described on the basis of six specimens from the Gavuvu River of West New Britain Island (Papua New Guinea). It differs from other Coelonotus species by a combination of morphomeristic values including: number of dorsal fin rays (45-47), number of subdorsal (4-5) and tail rings (35-37). The Folmer DNA barcode fragment of the COI mitochondrial gene shows that this new species is indeed a different genetic lineage from other Coelonotus species of this area.

International audience; In this paper, we describe a new non-damaging internal tissue sampling method for preserved collection of teleostean specimens. It was tested on freshwater pipefish, as external tissue sampling is made difficult by the lack of scales, the lack of pelvic fins, the atrophy of pectoral and anal fins. The internal tissue is detached by scratching the inside of the urogenital papilla with a fine metallic probe. 95% ethanol is injected using a fine syringe, and then sucked back into the syringe with the detached tissue. This protocol has been tested on 6 specimens from 5 species of pipefish. For each specimen DNA was extracted from the internal tissue, a caudal fin clip, and when possible, eggs sampled from the male brooding pouch. Partial Cytochrome c oxydase I (COI) was amplified and sequenced. For each specimen, the 582 bp long sequences obtained from the internal tissue, the fin clip and the eggs were identical. These results validate this non-damaging internal tissue sampling method, which leaves absolutely no trace on the specimen. Although this method was developed on pipefish, it could be applied to other teleostean, even precious museum collection specimens such as type specimens. The aim of this paper, using the example of freshwater pipefish, is to present this method, which aims at preserving precious collection specimens while still valorising them.

A new species of Sicyopterus, a freshwater goby, is described from streams of Papua New Guinea on the island of West New Britain, where specimens were caught during two field missions in 2015 and 2019. It differs from other species belonging to the genus by a combination of characters including the upper lip morphology, a second dorsal fin with one spine and 10 segmented rays, the scales in the lateral, predorsal, transverse back, transverse forward and zigzag series, and live colours with courting males having a coal black body with occasionally a pearl white necklace.

International audience; A new species of Sicyopus, a sicydiine goby, is described from specimens collected in streams of New Britain (Papua New Guinea). It differs from other species of this amphidromous genus by a combination of characters including a second dorsal fin with one spine and ten segmented rays, fewer scales in lateral series and transverse back series, and smaller predorsal and caudal peduncle lengths.; Une nouvelle espèce de Sicyopus, un gobie d’eau douce, est décrit de Nouvelle-Bretagne (Papouasie-Nouvelle-Guinée). Il diffère des autres espèces de ce genre amphidrome par plusieurs caractères dont une seconde nageoire dorsale avec un rayon épineux et dix segmentés, moins d’écailles à la ligne latérale et en série transverse postérieure, et de plus petites longueurs prédorsale et du pédoncule caudal.

International audience; A new species of Sicyopus, a sicydiine goby, is described from specimens collected in streams of New Britain (Papua New Guinea). It differs from other species of this amphidromous genus by a combination of characters including a second dorsal fin with one spine and ten segmented rays, fewer scales in lateral series and transverse back series, and smaller predorsal and caudal peduncle lengths.; Une nouvelle espèce de Sicyopus, un gobie d’eau douce, est décrit de Nouvelle-Bretagne (Papouasie-Nouvelle-Guinée). Il diffère des autres espèces de ce genre amphidrome par plusieurs caractères dont une seconde nageoire dorsale avec un rayon épineux et dix segmentés, moins d’écailles à la ligne latérale et en série transverse postérieure, et de plus petites longueurs prédorsale et du pédoncule caudal.

International audience; Rivers of the Caribbean islands harbour a freshwater fauna mainly constituted of migrant diadro- mous species. In these hyperturbulent ecosystems, the primary producers are mostly represented by a thin epi- lithic biofilm, mainly composed of diatoms. Comparison of the diatoms available from the environment with the ones consumed and located in the digestive tracts of two gobiid fish, Sicydium punctatum Perugia, 1896 and Sicydium plumieri (Bloch, 1786) were made at twelve sampling locations, located upstream or downstream of six rivers, in Guadeloupe. One hundred and ninety-one epilithic diatom species were identified. A statistical approach was used to determine diatoms that best characterize the two species digestive tracts content (i.e.“diagnostic species”) and to evaluate the statistical relationship between species abundances and groups of sites or conditions. Eight taxa belonging to five families were considered as significant diagnostic species of digestive tracts from fish collected upstream (Achnanthidium subhudsonis, Achnanthes rupestoides, Diadesmis contenta, Diadesmis sp., Eolimna sp., Navicula (dicta) seminulum, Navicula difficillima and Nupela sp.), and five taxa belonging to three families were considered as significant diagnostic species for fish collected downstream (Gomphonema parvulum, Navicula arvensis, Navicula cruxmeridionalis, Nitzschia frustulum and Navicula incarum). Results indicate selective consumption of epilithic diatoms by the two major fish observed in the midand upper stream of Caribbean rivers; Les rivières des îles des Caraïbes abritent une faune essentiellement composée d’espèces diadromes, migratrices. Dans ces écosystèmes hyperturbulents, le compartiment producteur est principalement constitué par un biofilm épilithique où les diatomées sont majoritaires. Une comparaison des assemblages diatomiques présentsdans l’environnement avec ceux situés dans les tubes digestifs de deux Gobiidae, Sicydium punctatum Perugia, 1896 et Sicydium plumieri (Bloch, 1786) a été réalisée sur douze stations localisées en amont ou en aval de six rivières, en Guadeloupe. Cent quatre-vingt-onze taxons de diatomées épilithiques ont été identifiés. Une approche statistique a été utilisée pour déterminer les diatomées qui caractérisaient le mieux les contenus digestifs desdeux poissons (i.e. “espèce indicatrice”) et évaluer la relation statistique entre les abondances diatomiques, les sites ou encore les conditions amont/aval. Huit taxons appartenant à cinq familles de diatomées se sont révélés indicateurs des contenus digestifs de poissons situés en amont des rivières (Achnanthidium subhudsonis, Achnanthes rupestoides, Diadesmis contenta, Diadesmis sp., Eolimna sp., Navicula (dicta) seminulum, Navicula difficillima et Nupela sp.), et cinq taxons appartenant à trois familles se sont révélés indicateurs chez les poissons pêchés en aval des rivières (Gomphonema parvulum, Navicula arvensis, Navicula cruxmeridionalis, Nitzschiafrustulum et Navicula incarum). Les résultats ont montré une consommation sélective de certaines espèces de diatomées par les deux espèces de poissons majeurs des cours d’eau moyens et supérieurs aux Antilles.

International audience; To fight the banana weevil, organochlorine insecticide was used in Guadeloupe, leading to a contamination of the rivers by chlordecone, for which the molecules are long lasting and persist in the environment although its use was banned in the 90s. In the rivers, Sicydiinae gobies of the genus Sicydium represent key species of the ecosystem. They are herbivorous and feed on the epilithic biofilm by scraping it off the rocks. We undertook in vitro experiments in order to obtain preliminary results on the effect of the pollutant on the behaviour of Sicydium punctatum Perugia, 1896, and on its food source. It seems that the pollutant has no effect on the social behaviour of this species. However, we noted that in polluted conditions, the biofilm composition is altered, depriving S. punctatum of its favoured diatom species, which S. punctatum usually “grows” by having a gardening behaviour.

International audience; The species of Schismatogobius from Papua New Guinea to Samoa are reviewed and compared to the three known species described from the area. Eleven species are recognized including seven new species. These are described using genetic and morphomeristic approaches. The species differ by a high percentage of divergence in partial COI gene (636 bp) and by several characters including the number of pectoral fin rays, the pattern of the ventral surface of the head in males and/or females, the pectoral fin colour pattern, the jaw length/head length ratio or the jaw length of male and/or female, and the fin lengths.

International audience; A new species of Lentipes, a freshwater Sicydiinae goby, is described from streams of SolomonIslands. It differs from other species of the genus by a combination of characters including an urogenital papillalacking lateral lobes and retractable into a sheath-like groove, the number of pectoral fin rays, the number ofscales, the number of tricuspid teeth in the upper jaw, and a specific body colour in male.; Une espèce nouvelle de Lentipes, gobie Sicydiinae d’eau douce, est décrite des îles Salomon. Elle diffère des autres espèces du genre par plusieurs caractères dont une papille urogénitale sans lobes latéraux et rétractable dans une cavité, le nombre de rayons aux nageoires pectorales, le nombre d’écailles, le nombre de dents tricuspides à la mâchoire supérieure et une coloration caractéristique des mâles.

International audience; A new species of Sicyopterus, freshwater goby, is described from Sumatra and Java, Indonesia. It differs from other species belonging to the genus by a combination of characters including two lateral clefts on the crenulated upper lip, a second dorsal fin with one spine and 10 segmented rays, second and third rays of the first dorsal fin filamentous, more lateral, predorsal and transverse back scales, and a reddish caudal fin in male with a slight blue line on the upper and lower parts.; Une espèce nouvelle de Sicyopterus, gobie dulçaquicole, est décrite sur la base de spécimens collectés à Sumatra et Java (Indonésie). Elle diffère des autres espèces du genre par plusieurs caractères incluant deux encoches latérales sur la lèvre supérieure crénelée, une seconde nageoire dorsale avec un rayon épineux et 10 rayons mous, les deuxième et troisième rayons de la première dorsale filamenteux, un plus grand nombre d’écailles en ligne longitudinale, en série prédorsale et transverse postérieure, ainsi qu’une nageoire caudale rouge bordée d’une ligne bleue chez le mâle.

Five new species of Sicyopterus, freshwater gobies, are described from streams of Papua new Guinea and Papua Province, indonesia. they differ from other species belonging to the genus by a combination of characters including the upper lip morphology, the number of soft rays in the second dorsal fin, the scales in the lateral, predorsal, transverse back, transverse forward and zigzag series, sexual dimorphism, and live colours.

Sicyopus (Smilosicyopus) pentecost n. sp., a carnivorous freshwater goby, is described on the basis of nine specimens (five males, four females) collected from high gradient streams on the islands of Pentecost (Vanuatu) and Bélep (New Caledonia). This species differs from other species of the subgenus Smilosicyopus by a combination of characters that include more upper jaw teeth (21-26), less scales in lateral series (14-29), less scales in zigzag series (11-14), a greater length in second dorsal fin in female, and a shorter caudal peduncle.

Sicyopterus lagocephalus is an amphidromous fish: adults live in rivers, but after hatching larvae are carried to the sea (dispersion stage). After a certain time spent at sea, post-larvae return to rivers to grow and reproduce. Sicyopterus lagocephalus post-larvae recruiting to Reunion Island rivers (Mascarene Archipelago), provide an important food source to local populations and this fishing activity has a significant socio-economic impact. A better understanding of the early life traits of this species and the characterisation of larval stages should improve the biological and physiological knowledge needed to understand the processes involved in the dispersion stage and help managers to implement conservation measures. In Reunion Island, we characterised the development of larvae from hatching to migration to the sea. The results show that larvae do not undergo any development in freshwater, and that it is the arrival at sea that triggers the morphological transformations. Our results have also revealed that development is quicker when the temperature is high and that development varies according to water depth during the downstream migration. In natural temperature conditions, the maximum survival rate in freshwater is four days. This suggests that when the downstream migration takes too long because of anthropogenic or hydraulic factors, the free embryos would die before they reach the sea.

International audience

International audience; Sicyopterus lagocephalus post-larvae migrating in Mascarene Archipelago rivers, La Réunion Island, provide an important food source to local populations and fishing activity has a socioeconomic impact. Improved knowledge of the life traits and the characterisation of post-larval stages should enable a better understanding of physiological changes triggering migratory behaviour. It would also help to explain the recruitment processes to managers and to implement conservation measures for stock management. Sicyopterus lagocephalus is an amphidromous fish: adults live in rivers, but larvae are carried to the sea after hatching. The present study characterised the metamorphosis and post-larval stages of Sicyopterus lagocephalus during river recolonisation on La Réunion Island. The results show that cranium reorganisation and pectoral fins transformation are part of the first and major transformations and are completed less than 2 weeks after freshwater colonisation (post-larval stages PL1 and PL2). These transformations, mobilising all the available calcium, seem to be critical for survival in their new environment. Individuals then progressively acquire pigmentation, complete scalation and the fork at the end of the caudal fin disappears (juvenile stages J1 and J2). The end of the recruitment phase takes place 21 to 28 days after entering the river mouth, when territorial behaviour appears

Three new species of Lentipes (L. argenteus, L. ikeae and L. mekonggaensis), freshwater gobies, are described from streams of Sumatra, Java, Bali and Sulawesi (Indonesia). They differ from other species of the genus by a combination of characters including an urogenital papilla lacking lateral lobes and retractable into a sheath-like groove, the number of pectoral fin rays, the number of scales, tricuspid teeth in the upper jaw, and a specific body colour in males.

The species of Schismatogobius from Papua New Guinea to Samoa are reviewed and compared to the three known species described from the area. Eleven species are recognized including seven new species. These are described using genetic and morphomeristic approaches. The species differ by a high percentage of divergence in partial COI gene (636 bp) and by several characters including the number of pectoral fin rays, the pattern of the ventral surface of the head in males and/or females, the pectoral fin colour pattern, the jaw length/head length ratio or the jaw length of male and/or female, and the fin lengths.