Gobionellus Oceanicus Research Articles

Population structure of Gobiidae in a tropical urban estuary

As spatiotemporal variations in estuaries affect the population structure of species, the study aimed to analyze the distribution of species of the family Gobiidae in the Capibaribe River's estuary city of Recife (northeastern Brazil). Sampling was performed bi-monthly from February 2009 to December 2012 at two sampling stations. The weight-length relationship of the species was determined using potential regression analysis. Density and biomass values were determined for each species per sampling station and season. The Mann-Whitney test was used to compare spatial and seasonal differences in abundance. A non-metric multidimensional scaling ordination was used to assess changes in species composition. Seven hundred eighty-eight individuals were caught. The most representative species of Gobiidae was Ctenogobius boleosoma, followed by Evorthodus lyricus and Gobionellus oceanicus. The relationship between total weight (TW) and standard length (SL) was potential and significant for both C. boleosoma (TW = 0.04SL2.1815) and E. lyricus (TW = 0.0272SL2.795), and both exhibited negative allometric growth. The analysis of the main species' spatial variation demonstrated a significant difference in the number of individuals for C. boleosoma (U = 528; p = 0.000005) and E. lyricus (U = 312; p = 0.000000). No significant difference in abundance was found between the dry and rainy season for either C. boleosoma (U = 1052.2; p = 0.4659) or E. lyricus (U = 1054; p = 0.4726). The two most abundant species have similar habits and customarily inhabit stressful environments. Ctenogobius boleosoma and E. lyricus are residents of the Capibaribe River's estuary, and both move to regions near the outfall of the river in the rainy season.

Meiofauna versus macrofauna as a food resource in a tropical intertidal mudflat

Evaluations of the functioning of benthic marine food webs could be improved by quantifying organic matter fluxes from the meiofauna to higher trophic levels. In this study, we measured the simultaneous ingestion of meiofauna and macrofauna by common dwellers of a tropical intertidal mudflat on the coast of Amazonia. The meiofauna and macrofauna (tanaid) communities of a tropical intertidal mudflat of French Guiana were separately enriched with 15N and 13C, respectively. The enriched preys were then used as tracers during feeding experiments with common predators of different sizes and feeding mechanisms: a Portunidae crab (Callinectes bocourti), a Penaeidae shrimp (Farfantepenaeus subtilis), and a Gobiidae fish (Gobionellus oceanicus). In feeding experiments with all predators except crabs, feeding rates increased with the availability of meiofauna and macrofauna food sources. The ability of consumers to ingest their food selectively was evaluated by calculating the differences in the ratio of macrofauna to meiofauna between the (1) ingested material and (2) that available in the environment. Larger predators showed a higher degree of preferential macrofauna ingestion than smaller predators, consistent with the optimal foraging theory. For large predators, the meiofauna would be important only during early life or in the absence of large food items.

Ichthyoplankton of the Southern Waters of the North Atlantic: 1. Morphology in Poorly-Studied Larvae of Coastal Species

The larvae and/or juveniles of coastal species were found in the composition of oceanic ichthyoplankton sampled during the 43rd expedition of R/V “Akademik Vavilov” in the southern waters of the North Atlantic. These fish included insufficiently-studied taxonomic forms from five families: Myripristis jacobus (Holocentridae), Ctenogobius sp., Gobionellus oceanicus, Gobioides grahamae (Gobiidae), Eleotris sp. 1., Dorminator maculatus (Eleotridae), Spariosoma sp. 1 (Scaridae), and Pontinus nematophthalmus, (Scorpaenidae). The paper presents illustrated descriptions of these forms and discusses the problems of their identification.

Dynamics of early life‐history stages of fish along an estuarine gradient

AbstractThis study aimed to identify the spatial and temporal patterns of composition and distribution of early life‐history stages of fish along an estuarine gradient. Samples were collected quarterly between April 2010 and January 2011 using conical‐cylindrical plankton nets in the Vaza Barris estuarine river system (NE Brazil). A total of 38,781 fish eggs and 3,526 larvae, representing 20 families and 42 taxa, were caught. The most abundant larval taxa were Microgobius meeki, Ctenogobius gr. smaragdus/boleosoma, Gobionellus oceanicus, Ctenogobius gr. stigmaticus/saepepallens/shufeldti, Bairdiella ronchus, Achirus sp., Trinectes sp., Stellifer rastrifer and S. stellifer, accounting together for 34.5% of the total catch. Ichthyoplankton distributions were characterized by high seasonal and spatial variability mainly attributed to the environmental characteristics of the estuary. Overall, lower estuarine region served as important accumulation areas for ichthyoplankton, concentrating the greatest diversity and abundance. Salinity gradient, water temperature, and inorganic nutrients were the main variables that affected the larval fish assemblages, presumably influencing spawning, development and survival of individuals or through their effect on food supply. Moreover, this study reinforced the concept that hydrological variations may have a strong influence on estuarine species retention and marine species immigration. Finally, this study highlights the importance of estuaries for the growth and maintenance of stocks of fish species, and the development of strategies to protect these habitats is of utmost relevance.

The integument of the nonamphibious goby Gobionellus oceanicus: Its functional morphology and respiratory capacity.

Facultative air-breathing fish can exchange respiratory gases using an air-breathing organ (ABO), such as the oral cavity of the integument, during environmental hypoxia. The goby Gobionellus oceanicus inhabits areas subject to environmental hypoxia; however, its ABO is unknown. To investigate the respiratory potential of G. oceanicus, the gill and integument surface area, diffusion capacity, and their diffusion barrier thickness were measured. Our results show that although gill surface area is smaller than observed in other facultative air-breathing fish, but it has all features necessary to perform aquatic gas exchange. Additionally the integument of the palate has a short diffusion barrier thickness and a large calculated O2 -diffusion capacity suggesting that it functions as the ABO.

Gill Morphology and Na+/K+-ATPase Activity of Gobionellus oceanicus (Teleostei: Gobiidae) in an Estuarine System.

Gobionellus oceanicus is a species widely distributed on the Atlantic coast and may be susceptible to anthropic effects. This study evaluated the morphology and the Na+/K+-ATPase activity of G. oceanicus gills considering the concentration of metals in the fish and Subaé River estuary. Although the metal concentrations detected in the water and sediment did not exceed certain limits, CONAMA (Brazilian Environment Council), TEL (Threshold Effect Level), and PEL (Probable Effect Level), the metals levels in gills plus muscle and skin of G. oceanicus were above the permitted setting of the Ministry of Health, Brazil. The pavement epithelial cells (PVC) of the gill filament was observed that there were long microridges either in the apical surface or in the lamella; especially, microridges degeneration was shown in some PVC from filament epithelium. The number of ionocyte and the volume density were (0.02 ± 0.001)/μm and (0.38 ± 0.27)%, respectively. The activity of Na+/K+-ATPase was 1.13 ± 0.76μMPimgprotein-1h-1. We describe the volume density and number of ionocytes and Na+/K+-ATPase enzymatic activity in G. oceanicus for the first time, which is useful for basic and comparative future studies to support aquatic biomonitoring.

The influence of selected environmental parameters and habitat mosaics on fish assemblages in a South American estuary

Coastal environments are faced with constant habitat modification and biodiversity loss due to human occupation. Estuaries are considered to be highly productive and shelter heterogeneous habitats such as mangrove forests, tidal creeks, tidal mud flats and sandy beaches, which are important for the maintenance of natural resources. The present study aims to evaluate how different shallow juvenile habitats (sandy beaches, mangrove shoreline habitats and dense macrophyte habitats) influence fish during their early life stages in a tropical estuary of Brazil. Monthly samples using a beach seine net from July 2012 to June 2013 were collected in eight shallow areas of the São Mateus River estuary. The fish assemblage comprised mainly juvenile and small-sized fish, which included ecologically and commercially important species. Small recruits of Atherinella brasiliensis and Ctenogobius boleosoma were most abundant in the autumn, while Rhinosardinia bahiensis and Centropomus undecimalis were highly abundant during the winter. The water salinity recorded in the mid and lower estuarine portions was the most important variable for the distribution of A. brasiliensis and Sphoeroides spengleri, whereas Anchovia clupeoides, C. undecimalis, C. parallelus and Gobionellus oceanicus were positively correlated with the water depth of the upper estuarine portion. The fish species T. paulistanus, Genidens genidens and Achirus lineatus were related to the water turbidity in the upper portion. Thus, the heterogeneous shallow water habitats (and their associated environmental parameters) of the São Mateus River estuary are potential nursery grounds for the early life stages of a variety of fish species, which highlights the importance of these areas for local biodiversity management.

Cadmium and lead in seafood from the Aratu Bay, Brazil and the human health risk assessment.

This study aimed to evaluate cadmium (Cd) and lead (Pb) levels in seafood and perform a risk assessment based on individual food consumption frequency of inhabitants of the Aratu Bay, Brazil. From December 2013 to November 2014, ready-to-market seafood, including fish [pititinga (Lile piquitinga) and small green eel (Gobionellus oceanicus)], mollusks [mussel (Mytella guyanensis) and oyster (Crassostrea rhizophorae)], and crustaceans [white shrimp (Litopenaeus schmitti) and blue crab (Callinectes exasperatus)], were purchased bimonthly from a local artisanal shellfish harvester. Metal levels were analyzed by graphite furnace atomic absorption spectrometry (GFAAS). Based on the volunteer’ seafood consumption, estimates of the non-carcinogenic target hazard quotients (THQs) were calculated. The annual concentrations (μg/g, w/w) of Cd were 0.007 (±0.001) in crustaceans, 0.001 (±0.0003) in fish, and 0.446 (±0.034) in mollusks. Lead levels were <limit of detection (LOD) in crustaceans, 0.044 (±0.0032) in fish, and 0.111 (±0.009) in mollusks. All values were within the international guidelines. We observed that 90.9 % of the responders presented an average THQ < 1, which is classified as negligible risk; however, 9.1 % presented THQs between ≥1 and <9.9. These data are important to inform the community of the imminent exposure risk through communication strategies, with the purpose of minimizing exposure and, consequently, the health effects associated with it.

Changes in the composition of ichthyoplankton assemblage and plastic debris in mangrove creeks relative to moon phases.

Lunar influence on the distribution of fish larvae, zooplankton and plastic debris in mangrove creeks of the Goiana Estuary, Brazil, was studied over a lunar cycle. Cetengraulis edentulus, Anchovia clupeoides and Rhinosardinia bahiensis were the most abundant fish larvae (56·6%), independent of the moon phase. The full moon had a positive influence on the abundance of Gobionellus oceanicus, Cynoscion acoupa and Atherinella brasiliensis, and the new moon on Ulaema lefroyi. The full and new moons also influenced the number of zoeae and megalopae of Ucides cordatus, protozoeae and larvae of caridean shrimps, and the number of hard and soft plastic debris, both <5 and >5 mm. Micro and macroplastics were present in samples from all 12 creeks studied, at densities similar to the third most abundant taxon, R. bahiensis. Cetengraulis edentulus and R. bahiensis showed a strong positive correlation with the last quarter moon, when there was less zooplankton available in the creeks and higher abundance of microplastic threads. Anchovia clupeoides, Diapterus rhombeus, U. lefroyi and hard microplastics were positively associated with different moon phases, when calanoid copepods, Caridean larvae and zoeae of U. cordatus were highly available in the creeks. Cynoscion acoupa, G.oceanicus and A. brasiliensis were strongly associated with the full moon, when protozoeae of caridean shrimps and megalopae of U. cordatus were also highly available, as were hard and soft macroplastics, paint chips (<5 mm) and soft microplastics. The results reinforce the role of mangrove creeks as nursery habitats. The moon phases influenced the distribution of fish larvae species, zooplankton and plastic debris by changing their compositions and abundances in the mangrove creeks of the Goiana Estuary when under the influence of different tidal current regimes.

First Record of Paratenic Hosts of the Swimbladder Nematode Anguillicola crassus in North America.

Anguillicola crassus is a non-native parasite of the American eel, Anguilla rostrata. Since being introduced into North America, the nematode has spread rapidly across the range of A. rostrata, but paratenic hosts, which may facilitate parasite dispersion, have yet to be identified in the region. We investigated infection of larval A. crassus in 261 fish specimens belonging to 23 species and 12 orders collected from estuarine habitats in South Carolina (salinities 0-9 ppt) and Nova Scotia (10-18 ppt). A total of 35 fish belonging to 5 species and 3 orders were infected with the third-stage larvae (L3) of A. crassus, providing the first record of paratenic hosts for the parasite in North America. In South Carolina, high prevalence and abundance of the worm were found in spot (Leiostomus xanthurus), silver perch (Bairdiella chrysoura), and highfin goby (Gobionellus oceanicus), and a high prevalence but lower abundance was found in mummichog (Fundulus heteroclitus). In Nova Scotia, 2 nematodes were found in a single specimen of tomcod (Microgadus tomcod). All of the infected species are associated with a benthic lifestyle, and some of them are known to move between estuaries along the coastline. Lower infection rates in Nova Scotia may be associated with lower water temperatures and/or higher salinity of the sampling site. Most of the L3 were found encapsulated in mesenteric tissue around the intestine and stomach. No L4 or pre-adult worms were found. Mean body length of the L3 was smaller than L3 stages found in American eels from Cape Breton. This suggests that development of A. crassus is arrested at the L3 in the 5 fish species reported here, supporting their status as paratenic hosts.

Seasonal distribution and interactions between plankton and microplastics in a tropical estuary

The seasonal migration of a salt wedge and rainfall were the major factors influencing the spatiotemporal distribution of ichthyoplankton and microplastics along the main channel of the Goiana Estuary, NE Brazil. The most abundant taxa were the clupeids Rhinosardinia bahiensis and Harengula clupeola, followed by the achirid Trinectes maculatus (78.7% of the catch). Estuarine and mangrove larvae (e.g. Anchovia clupeoides, Gobionellus oceanicus), as well as microplastics were ubiquitous. During drier months, the salt wedge reaches the upper estuary and marine larvae (e.g. Cynoscion acoupa) migrated upstream until the zones of coastal waters influence. However, the meeting of waterfronts in the middle estuary forms a barrier that retains the microplastics in the upper and lower estuary most part of the year. During the late dry season, a bloom of zooplankton was followed by a bloom of fish larvae (12.74 ind. 100 m−3) and fish eggs (14.65 ind. 100 m−3) at the lower estuary. During the late rainy season, the high freshwater inflow flushed microplastics, together with the biota, seaward. During this season, a microplastic maximum (14 items 100 m−3) was observed, followed by fish larvae maximum (14.23 ind. 100 m−3) in the lower estuary. In contrast to fish larvae, microplastics presented positive correlation with high rainfall rates, being more strictly associated to flushing out/into the estuary than to seasonal variation in environmental variables. Microplastics represented half of fish larvae density. Comparable densities in the water column increase the chances of interaction between microplastics and fish larvae, including the ingestion of smaller fragments, whose shape and colour are similar to zooplankton prey.

Chromosomal Mapping of Repetitive DNAs in Gobionellus oceanicus and G. stomatus (Gobiidae; Perciformes): A Shared XX/XY System and an Unusual Distribution of 5S rDNA Sites on the Y Chromosome

With nearly 2,000 species, Gobiidae is the most specious family of the vertebrates. This high level of speciation is accompanied by conspicuous karyotypic modifications, where the role of repetitive sequences remains largely unknown. This study analyzed the karyotype of 2 species of the genus Gobionellus and mapped 18S and 5S ribosomal RNA genes and (CA)₁₅ microsatellite sequences onto their chromosomes. G. oceanicus (2n = 56; ♂ 12 metacentrics (m) + 4 submetacentrics (sm) + 1 subtelocentric (st) + 39 acrocentrics (a); ♀ 12m + 4sm + 2st + 38a) and G. stomatus (2n = 56; ♂ 20m + 14sm + 1st + 21a; ♀ 20m + 14sm + 2st + 20a) possess the highest diploid chromosome number among the Gobiidae and have different karyotypes. Both species share an XX/XY sex chromosome system with a large subtelocentric X and a small acrocentric Y chromosome which is rich in (CA)₁₅ sequences and bears 5S rRNA sites. Although coding and noncoding repetitive DNA sequences may be involved in the genesis or differentiation of the sex chromosomes, the exclusive presence of 5S rDNA sites on the Y, but not on the X chromosome of both species, represents a novelty in fishes. In summary, the karyotypic differences, as well as new data on the sex chromosome systems in these 2 Gobiidae species, confirm the high chromosomal dynamism observed in this family.

Composition and temporal patterns of larval fish communities in Chesapeake and Delaware Bays

Composition and temporal patterns of larval fish communities in Chesapeake and Delaware Bays

Nível Trófico de Peixes da Costa Brasileira

Com o objetivo de entender o papel ecologico da fauna marinha de peixes e contribuir para a construcao de modelos de balanco de massa trofica, o presente estudo determinou o nivel trofico (TL) para 131 especies de peixe pertencentes a 52 familias e 18 ordens. Todas as informacoes disponiveis (artigos de revistas cientificas, assim como literatura cinza) sobre conteudo alimentar das especies de peixes marinhos da costa brasileira foram tabuladas por especies, area de estudo e ano. Os valores de TL foram calculados usando o TrophLab, que e um aplicativo para estimar o TL e seu erro padrao (SE), a partir de dados da composicao de dieta. O TL variou de 2, como os herbivoros Gobionellus oceanicus (Gobiidae), a 4,80, para piscivoros Prionace glauca (Carcharhinidae). O valor medio de TL foi de 3,60. A maioria (38%) dos valores de TL variou entre 3,0 e 3,5. Foram detectadas diferencas entre as estimativas de TL do presente estudo e aquelas disponiveis por algumas especies no FishBase. As diferencas observadas podem ser explicadas por inumeros fatores, incluindo procedimentos de amostragens, numero total de estomagos analisados, variacao do comprimento da populacao amostrada. Relacoes significativas foram determinadas entre as estimativas de TL do presente estudo com os disponiveis no FishBase, e com o comprimento maximo do corpo das especies. Palavras-chave : Ecologia trofica, Ictiofauna, Nivel trofico, Oceano Atlântico sudoeste.

Structure and dynamics of Gobiidae larvae (Teleostei, Perciformes) in a tropical estuary: seasonal relationships with tidal cycles

This study aims to describe the spatial and temporal distribution patterns of Gobiidae larvae at a tropical estuarine system in south-east Brazil (Macaé). The samples were collected in six stations, through oblique hauls using a bongo net (330 µm mesh size), coupled to a flowmeter, during the night in the ebb and flood tides in March, July and October 2006 and in February 2007. In the Macaé River estuary was collected a total of 1,234 Gobiidae larvae, representing nine taxa. The highest densities occurred in the river mouth during the flood tide in the rainy season. The most abundant groups were: Gobiosoma parri, Gobionellus oceanicus and Ctenogobius boleosoma. Gobiosoma parri was also dominant at the Macaé estuary, which also presented higher densities in the coastal stations during the rainy season (March), both the flood as the ebb tide. Gobionellus oceanicus and Ctenogobius boleosoma were characteristic of the dry season in the mouth and river stations during the flood tide. The abiotic factors chlorophyll-a and temperature were considered biologically significant for Gobiidae larvae distribution. The spatial and seasonal variations together with the tide influence the distribution of the fish larvae Gobiidae family in the Macaé River estuary and its coastal zone.

Occurrence of Gobiidae larvae in a tropical Brazilian estuary, with particular emphasis on the use of size classes to categorize species guilds

The structure and seasonal dynamics of larvae of the Gobiidae family in the Mucuri Estuary (Bahia, Brazil) were studied for nine consecutive years. Sampling was conducted at three stations in the lower estuary channel, between 2002 and 2010, in relation to season, day and night and tidal variations. A total of 5802 Gobiidae larvae, representing 15 taxa (12 species and three morphotypes), were collected in the Mucuri Estuary during this time. The highest mean ± s.d. density of fish larvae, 54·7 ± 79·8 larvae 100 m(-3), was recorded during the flood tide and night sampling. Ctenogobius boleosoma was the most abundant species (68%), being dominant in the rainy and dry seasons and had a long reproductive period. This species was classed as a marine estuarine-opportunist because it was observed at high frequencies and active larvae entering the estuary between 6·1 and 12·0 mm standard length (L(S)). Gobionellus oceanicus, second in abundance (12%), occurred only in later larval stages but did not use the estuary as a preferred location for spawning, being classed a marine estuarine dependent. Microgobius carri (11%) was represented in all L(S) classes and was resident in the estuary for spawning, remaining there throughout their life cycle. The other species were considered rare due to their low densities and could not be classified in any guild.

Fish composition and assemblage structure in the estuarine mixing zone of a tropical estuary: comparisons between the main channel and an adjacent lagoon

Spatial patterns of an estuarine habitat used by fish assemblages were determined for a protected adjacent lagoon and two areas of the main estuarine channel in a small tropical estuary. The tested hypotheses are that protected areas in estuarine zones support comparatively higher fish richness and abundance and have more small-sized fishes than the main channel. The lagoon and channel areas had distinct fish assemblage structures. Several abundant species (e.g. Atherinella brasiliensis, Eugerres brasilianus, Geophagus brasiliensis, Achirus lineatus and Centropomus parallelus) were of a smaller size in the lagoon compared with the estuarine channel and probably use the lagoon as nursery grounds. Moreover, some species (e.g. Anchoa tricolor, Anchoa januaria, Gobionellus oceanicus and Poecilia vivipara) were abundant and occurred only in the lagoon, whereas others (e.g. Trinectes paulistanus, Ctenogobius shufeldti and Citharichthys arenaceus) reached their highest abundance in the lagoon and were rarely found in the estuarine channel. Seasonal variation in the fish assemblage structure was not significant, which may be related to dominance of estuarine resident species. We found that the lagoon supported comparatively higher fish richness and abundance compared with the main estuarine channel because of the more sheltered and structured habitat. These results provide a better understanding of the role of adjacent habitats to fish assemblage and an improved basis for estuarine rehabilitation.

Prey consumed by Guiana dolphin Sotalia guianensis (Cetacea, Delphinidae) and franciscana dolphin Pontoporia blainvillei (Cetacea, Pontoporiidae) in an estuarine environment in southern Brazil

The present study provides information about the diet of sympatric populations of small cetaceans in the Babitonga Bay estuary. This is the first study on the diet of these species in direct sympatry. The stomach contents of seven Guiana dolphins Sotalia guianensis and eight franciscanas Pontoporia blainvillei were analyzed. The prey of both cetaceans was mostly teleost fishes, followed by cephalopods. We identified 13 teleost fishes as part of the diet of the franciscanas, and 20 as part of the diet of Guiana dolphins. Lolliguncula brevis was the only cephalopod recorded, and was the most important prey for both cetaceans. Stellifer rastrifer and Gobionellus oceanicus were also important for franciscana, so as Mugil curema and Micropogonias furnieri were important for Guiana dolphins. Stellifer rastrifer and Cetengraulis edentulus were the fishes with the highest frequency of occurrence for franciscana (50%), while Achirus lineatus, C. edentulus, S. brasiliensis, Cynoscion leiarchus, M. furnieri, M. curema, Diapterus rhombeus, Eugerres brasilianus and G. oceanicus showed 28.6% of frequency of occurrence for Guiana dolphins. Franciscanas captured greater cephalopods than the Guiana dolphins in both total length (z= -3.38; n= 40; p&lt; 0.05) and biomass (z = -2.46; n = 40; p&lt;0.05). All of the prey species identified occur inside the estuary, which represents a safe habitat against predators and food availability, reinforcing the importance of the Babitonga Bay for these cetacean populations.

Historical and Environmental Distribution of Ichthyofauna in the Tropical Wetland of Pantanos de Centla, Southern Gulf of Mexico

Background. Thirty species were previously recorded for unstructured habitats (unvegetated soft substrates: USS) in Pantanos de Centla. However, a lack of information on the tropical ichthyofauna of the structured habitats such as marginal vegetation (MV), submerged macrophytes (SM) and coarse woody debris (CWD) emphasizes the importance of the aim of this paper that is the updating the records of the species distributed in these habitats, as they have been frequently reported as high biodiversity sites that are currently threatened by anthropogenic activities. Materials and methods. Sampling was carried out in 30 shallow sites, each with unstructured habitats and the three structured habitats, in Pantanos de Centla, a Ramsar wetland, over a period of three years. Fish were collected with a dip net, a drop net and a Renfro beam net. Results. A total of 6506 fish of 37 genera and 44 species were collected. Eleven species are new records for Pantanos de Centla, and the scientific name of 11 species was updated. The Poeciliidae and Cichlidae families are dominant with 10 and 13 species, respectively. Nine species of the genus Cichlasoma sensu lato were placed in six genera. Three species are new records for the Usumacinta Province. Ctenogobius claytoni, Gobionellus oceanicus, and Rhamdia quelen proved to be synonyms. Of all species, 84% were collected from USS, however, the number of species distributed in USS, MV, and SM was similar (CCj 0.4736-0.5813). Conclusion. Most of the species that were added to the previously recorded species list of Pantanos de Centla, inhabit structured habitats. This confirms the importance of including these habitats in surveys aimed at generating checklists, and of analysing the distribution of fish species in shallow tropical ecosystems.

Phylogenetic Analysis of the Genus Gobionellus (Teleostei: Gobiidae)

Abstract A cladistic analysis of the gobiid fish genus Gobionellus primarily using characters of the postcranial axial skeleton and the cephalic lateralis system gave evidence that the genus as historically conceived is polyphyletic. Its present recognition relies upon characters common to many species of gobionelline gobies. One group of six species is most closely related to the genus Gobioides. This group includes Gobionellus oceanicus and retains the name Gobionellus. Gobionellus is diagnosed by an extensive oculoscapular canal running from the snout to above the rear margin of the operculum with a unique A‘BCDFHKL’ pore pattern, a distally flared fourth neural spine that is spatulate in five of the six species, a vertical row of neuromasts on the rear field of the operculum, and elongate gill rakers on the anterior surface and lobes on the posterior surface of the epibranchial of the first gill arch. No unequivocal synapomorphies are offered for the genus excluding Gobioides. Fifteen species previous...