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Based on morphological and molecular analysis of Astronotus species, a new species is described from the Orinoco River and Gulf of Paria basins in Venezuela and Colombia. Morphologically, it differs from Astronotus crassipinnis and Astronotus ocellatus in pre-orbital depth, caudal peduncle depth, head width, and caudal peduncle length, with significant differences in average percentage values. Osteologically, it differs from the two described species by lacking a hypurapophysis on the parahypural bone (hypural complex) and having two or three supraneural bones. Another characteristic that helps diagnose the new species is the morphology of the sagitta otolith, which is oval with crenulated dorsal and ventral margins and a rounded posterior edge. Genetically, the new species is distinct from all the other lineages previously proposed for the genus, delimited by five single locus species delimitation methods, and also has unique diagnostic nucleotides. Phylogenetic analyses support the monophyly of the new species as well as all other species/lineages. Astronotus species have considerable genetic, anatomical, and sagitta otolith shape differences, but have few significant traditional morphometric and meristic differences, because there is high variability in counts of spines, soft dorsal-fin rays, and lateral-line scales. It is clear that this new species is genetically and anatomically differentiated from all other species within the genus, and deserves recognition as a new valid species.

Knowledge about the taxonomy and fish composition from the upper rio Paraúna (rio São Francisco basin) and upper rio Santo Antônio (rio Doce basin) in the middle portion of the Southern Espinhaço mountain range, state of Minas Gerais, Brazil is still incipient. Only few studies focusing on ichthyofaunistic diagnostic and species descriptions in the lower stretches of the rio Santo Antônio are available. Herein the aim was to provide a species list of the freshwater ichthyofauna from the headwaters of both basins in such region, and to verify the occurrence of threatened, exotic, and potentially new species. Sixty species were registered, with 34 associated to the upper rio Paraúna, and 40 to the upper rio Santo Antônio. Two species are included in some threatened category, three are exotics, and 14 represent potentially new species. An identification key of the fish species recorded in the area is also provided.

Iranian cichlids are isolated disjunct populations of the African cichlids group, restricted to the Hormuz Strait region in the Hormuz basin, and are a very important group from both zoogeographic and phylogenetic points of view. Thus, the osteological structures, as one of the most reliable structures, of the three nominal species of Iranian cichlid fishes, Iranocichla hormuzensis Coad, 1982, from the Mehran River, Iranocichla persa Esmaeili, Sayyadzadeh et Seehausen, 2016, from Khorgo hot spring, and Iranocichla sp., from the Kol River were described and compared. Ten specimens of each species were cleared and stained with Alcian blue and Alizarin red. A digital camera was used for taking pictures and CorelDraw X6 software for preparing drawings. The three species have some differences in the caudal fin skeleton, shape of the urostyle, neural spine of preural 2, hypural spines 2, and 3, anterior part of parhypural and hypurapophysis, the size of neural spines of preural 2 and 3, hypural 3 and 4, and epurals. Although there are some differences among the species, osteology of these species is very conservative and other traits like behavioral and molecular should be used.

Cytogenetic data for the genus Cichla Bloch et Schneider, 1801 are still very limited, with only four karyotype descriptions to date. The sum of the available cytogenetic information for Cichla species, points to a maintenance of the diploid number of 48 acrocentric chromosomes, considered a typical ancestral feature in cichlids. In the current study, we performed molecular and classical cytogenetic analyses of the karyotype organization of six species of Cichla , the earliest-diverging genus of Neotropical cichlids. We cytogenetically analysed Cichla kelberi Kullander et Ferreira, 2006, Cichla monoculus Agassiz, 1831, Cichla piquiti Kullander et Ferreira, 2006, Cichla temensis Humboldt, 1821, Cichla vazzoleri Kullander et Ferreira, 2006 and Cichla pinima Kullander et Ferreira, 2006, including three individuals that showed mixed morphological characteristics, likely from different species, suggesting they were hybrid individuals. All individuals analysed showed 2n = 48 acrocentric chromosomes, with centromeric heterochromatic blocks on all chromosomes and a terminal heterochromatic region on the q arm of the 2nd pair. Mapping 18S rDNA gave hybridization signals, correlated with the nucleolus organizer regions, on the 2nd pair for all analyzed individuals. However, we found distinct patterns for 5S rDNA: interstitially at the proximal position on 6th pair of four species ( C. kelberi , C. pinima , C. piquiti and C. vazzoleri ), and on the distal of the 4th pair in two ( C. monoculus and C. temensis ). Accordingly, we present here new data for the genus and discuss the evolutionary trends in the karyotype of this group of fish. In addition, we provide data that supports the occurrence of hybrid individuals in the Uatuma River region, mainly based on 5S rDNA mapping.

The fish specimens sent to Vienna by the Austrian naturalist Emanuel Ritter von Friedrichsthal (1809 – 1842) constitute one of the oldest collections of freshwater fishes from Central America. The holotype of Heros friedrichsthalii and specimens of Atherinella sardina were collected in the Rio San Juan or Lago de Nicaragua drainage in Nicaragua. The types of Cichlasoma urophthalmus stenozonum, Heros melanopogon and Heros triagramma, as well as specimens of Petenia splendida and Eugerres plumieri were most probably collected at Bacalar, Quintana Roo. Cichlasoma loisellei (Bussing, 1989), is synonymized with Parachromis friedrichsthalii (Heckel, 1840). The species hitherto referred to as P. friedrichsthalii takes the valid name Parachromis multifasciatus (Regan, 1905). A lectotype is designated for Cichlasoma urophthalmus stenozonum (Hubbs, 1936), which is synonymized with Mayaheros urophthalmus (Günther, 1862).

Three distinct and independent molecular-based species delimitation analyses were performed among the species and populations included within theAustraloherosautranigroup, based on sequences of the mitochondrial gene Cytochrome b: a tree-based method proposed by Wiens and Penkrot (WP), a Character-based DNA Barcoding (CBB) and coalescent species delimitation method termed the Bayesian Implementation of the Poisson tree processes (bPTP). The congruence of WP and CBB delimited 11 independent lineages (species), while the bPTP delimited just nine lineages. We did not favour any of the methods, and we considered the possibility of two slightly variant scenarios. A time-calibrated phylogenetic analysis is proposed based on the predominant congruence of the results of these three species delimitation methods herein applied. The monophyly of theA.autranispecies group was highly supported with maximum node support value and diagnosed by 11 nucleotide substitutions. The sister clade of theA.autranispecies group is the clade comprisingA.sp. Timbé do Sul andA.minuano. The phylogenetic analysis supports three main clades within theA.autranispecies group, supported by maximum node support value, with the Southern Mata Atlântica clade as the most basal clade. Divergence time estimates indicate that the diversification of theAustraloherosoriginated during the early Neogene, but only in the late Neogene did the processes of diversification in the southeast and north regions occur. Diversification within theAustraloherosautranispecies group occurred synchronically for the three main clades during the beginning of the Quaternary. It is demonstrated that molecular characters are valuable tools for species recognition, particularly in speciose groups with inconspicuous or difficult to record morphological characters. The resulting phylogeny of theAustraloherosautranigroup is highly compatible with the geological and biogeographic scenarios proposed for the Neogene and Quarternary shaping of the extant river basins of eastern Brazil. Despite the origin of theA.autranigroup being dated to the late Miocene, species level diversification occurred in the Pleistocene and was probably driven by headwater capture events and sea-level fluctuations.

A new species of Trematocranus, T.pachychilus sp. n., is described from Lake Malawi. So far, it has only been found at Jafua Bay, Mozambique. It can easily be distinguished from T.labifer by its molariform pharyngeal dentition. A morphometric study, including 24 measurements and 15 counts, was done to compare the new species with T.microstoma and T.placodon. Trematocranuspachychilus is characterised by its thick lips. This species further differs from T.microstoma by its bicuspid (vs. unicuspid) outer oral teeth, wide (vs. small) pharyngeal bone, and its head shape. It resembles T.placodon, from which it can be distinguished by its straight to concave head profile (vs. rounded), less-developed pharyngeal bones (vs. hypertrophied), and the presence of small to minute teeth on the lateral parts of the dentigerous area on the lower pharyngeal bone. A key to the species of Trematocranus is provided.

Morphological characters and phylogenetic trees generated by analyses of segments of two mitochondrial genes cytochrome b and cytochrome c oxidase I support recognition of three new species of the ‘Geophagus’ brasiliensis species group from coastal basins of northeast Brazil. All new species were diagnosed by exclusive morphological characters and exclusive nucleotide transformations. Geophagusrufomarginatus sp. n., from the Rio Buranhém Basin, is distinguished from all other species of the group by dorsal-fin lappets with red edges, the presence of longitudinal series of small light blue spots between the anal-fin spines and rays, and non-denticulated gill-rakers; it is closely related to G.brasiliensis and G.iporangensis. Geophagusmultiocellus sp. n., from the Rio de Contas Basin, is distinguished from all other species of the group by having small pale blue spots with minute bright blue dots at their centres, that are often vertically coalesced to form short bars on the caudal fin. Geophagussantosi sp. n., from the Rio Mariana Basin, is distinguished from all other species of the group by having blue stripes parallel to the dorsal and anal fin rays on their longest portions. Geophagusmultiocellus and G.santosi belong to the same clade of G.itapicuruensis. The clade composed by the Rio Paraguaçu Basin species was recovered as the sister group of the other species of the ‘G.’ brasiliensis species group.

Rondonacara, gen. nov. is herein described as a member of the tribe Cichlasomatini, being considered as the sister taxon of Laetacara. The new genus differs from all the other genera of Cichlasomatini by having transversal streaks originated at the insertion of spines and softs rays of dorsal fin. Additionally, the new genus differs from the other genera of the Cichlasomatini by its unique combination of character states: longitudinal stripe of the flank horizontally oriented, ending directed to caudal-fin base; conspicuous suborbital bar; caudal-fin base spot on the middle of the fin and not ocellated; preopercle without scales; two supra-neural; and uniserial predorsal squamation. Rondonacara is monotypic, including only Rondonacara hoehnei, re-described herein. This species was originally described from a tributary of the Araguaia River, Mato Grosso state, with unprecise locality. Currently, Rondonacara hoehnei is known only from a single locality, a tributary of the das Mortes River, Araguaia River basin, in the Brazilian Cerrado. The restrict distribution area, and the widespread and accelerated destruction of natural habitat strongly indicate that Rondonacara hoehnei is critically endangered

Apistogramma helkeri sp. n. is described from the drainage of the lower río Cuao in the Estado Amazonas of Venezuela. It is most similar to Apistogramma hongsloi Kullander, 1979, but differs from this species by its colouration and the shape of its dorsal fin. It can be distinguished from all the other described Apistogramma species by the following combination of characters: caudal fin rounded, hyaline and immaculate; dorsal fin lappets short, truncate, without extension or prolongation; caudal spot large, vertically extended; lateral band chainlike or running in a zigzag to 7th bar, not reaching caudal fin or caudal spot; upper pectoral spot present; three distinct abdominal stripes.

Iranocichla persa sp. n. is described from the Shur, Hasanlangi and Minab River drainages flowing into the Persian Gulf at the Strait of Hormuz in southern Iran. It is distinguished from Iranocichla hormuzensis, from the Mehran River drainage, by nuptial males having a bright orange breast and lower part of the head (vs. black), a poorly developed or invisible (vs. distinctive) “Tilapia-mark” in the dorsal fin and very clear white spots making almost wavy bars or stripes on the caudal fin (vs. without or with very few white spots). Mitochondrial DNA sequence characters suggest that both Iranocichla species are closely related but form two distinct clades, diagnosable by several fixed mutations in ND2, D-loop and partially by COI sequences. Populations from Kol River drainage, which is situated in-between the Mehran and the Shur River drainages, are more similar to Iranocichla hormuzensis in terms of their male nuptial coloration but to Iranocichla persa sp. n. in their mitochondrial sequence characters. Their status requires further investigation.

The present study expands the distribution of Krobia guianensis to the Araguari river basin, northern Brazil, previously know only from the coastal rivers basin of Guiana and Suriname. In addition, the correct catalog number of the holotype of Krobia guianensis is herein presented, as well a diagnosis for the species.

Andinoacara stalsbergi sp. n. is described from the drainages of trans-andean rivers and lakes at the Peruvian Pacific coast where this species occurs between Río Chira (Depto. Piura) in the north and Río Pisco (Depto. Ica) in the south. It is distinguished from its sister species A. rivulatus by the possession of a conspicuous white margin of both the dorsal and caudal fin and scales with light centres and contrasting dark marginal lines forming a fine reticulate pattern on the body sides. Studies based on molecular data confirm the status of Andinoacara stalsbergi sp. n. and reveal its phylogenetic relationships to its congeners. The reconstruction of the phylogeny within the genus Andinoacara results in the existence of two clades: one with A. stalsbergi sp. n., A. rivulatus, A. sapayensis and A. biseriatus and another with the remaining species.

A new species of Laetacara is described from the rio Verde, rio Araguaia basin, São Miguel do Araguaia, Goiás, Brazil; L. dorsigera is re-described. The new species from the rio Verde, rio Araguaia differs from all the species of the genus by its low dorsal-fin ray number. It is distinguished from L. thayeri by the presence of a caudal-fin peduncle spot and by the presence of cycloid scales on side of head. The new species also differs from L. fulvipinnis and L. fl avilabris by some meristic characters. It differs from L. dorsigera by a narrow ectopterygoid and by some meristic characters, and from L. curviceps and L. dorsigera by the lack of a spot on dorsal fin. Laetacara dorsigera differs from L. curviceps and the new species from the rio Verde, rio Araguaia basin by a wide ectopterygoid and by some meristic and morphometric characters; it is distinguished from the other species of the genus by some morphometric and meristic characters.

Nine new species of Australoheros from Southern Brazil are herein described: Australoheros autrani from rio São João basin; A. barbosae from rio Preto basin, rio Paraíba do Sul basin; A. ipatinguensis from rio Doce basin; A. macacuensis from rio Macacu basin, A. macaensis from rio Macaé basin, A. muriae from rio Muriaé basin, rio Paraíba do Sul basin; A. paraibae from rio do Peixe basin, rio Paraíba do Sul basin; A. robustus from córrego da Areia basin, rio Paraíba do Sul basin; and A. saquarema from lagoa de Saquarema system. The new species are easily distinguished from their congeners from South Brazil, Northern Argentina and North Uruguay (except A. scitulus) by having 12 caudal vertebrae (vs. 13 or more). The new species are distinguished from A. scitulus and A. forquilha by having no dark marks on side of head (vs. dark marks present on side of head), and differ from A. ribeirae by meristic counts. The nine new species differ from each other by several meristic counts, some morphometric measurements, shape of the snout and color pattern. A new phylogeny of the genus is required, because when these new species from Southern Brazil are included into the groups proposed by RÍCAN & KULLANDER (2006, 2008), the characters turns incongruent.

Dicrossus gladicauda sp. n. is described from the drainage of the lower río Atababo in Colombia. It can be distinguished from all other Dicrossus species by the asymmetrical shape of the caudal fin of adult males which develop a long filamentous streamer by the extension of their caudal-fin rays D3 and D4.

Australoheros ribeirae, new species, described from the rio Ribeira do Iguape basin, southeastern Brazil, has a colour patter similar to several undescribed species of Rio de Janeiro Sate. However, it differs from them by having a truncate neural process of the 2 nd caudal vertebra. Australoheros ribeirae differs from the other valid species of the genus by having a narrower ectopterigoid. It is distinguished from A. facetus (JENYNS , 1842) by coloration, meristic, morphometric and 2 osteological characters: a longer arm of epibranchial 1 and epibranchial 2 with two longer processes.

Two new species of zooplanktivorous haplochromine cichlids from Lake Victoria, Tanzania, are described and illustrated. These species closely resemble each other. Their affinities to other zooplanktivorous haplochromines from Lake Victoria are discussed. Haplochromis argens sp. n., which featured under nicknames (mainly H. “argens”) in more than 50 papers, was caught both in the Mwanza Gulf and the Emin Pasha Gulf, whereas H. goldschmidti sp. n. was only found in the Emin Pasha Gulf. Of the latter species only males are available, but it seems unlikely that it represents a case of male colour polymorphism as several presumably unrelated characters differ in sympatry between the two species, suggesting that there is no gene flow. Statistical analysis revealed that the overall difference between the two species is greater than that between the populations from the two locations. Body depth of the two species in sympatry in the Emin Pasha Gulf was more similar than that of H. goldschmidti sp. n. and the allopatric population of H. argens sp. n. from the Mwanza Gulf, which may indicate an overall environmental effect. However, several measurements related to the width of snout and mouth differed more between the populations of the two species in sympatry than between the allopatric populations. In contrast to a group of zooplanktivorous species that recovered successfully after environmental changes in the lake, H. argens sp. n. is among a group that became extremely rare and probably is in danger of extinction; the conservation status of H. goldschmidti sp. n. is currently unknown.

Background. Metals discharged in wastes from different industries into wetland ecosystems pose a serious threat to the receiving environment. Biotic components grown in the area amass such metals within their body through nutritional uptake and accumulation. The present investigation was carried out to study the extent of accumulation of different waste metals in tissues of cichlids commonly cultured in composite industrial wastewater-fed fishponds (Bheris) in East Calcutta Wetlands (ECW), a Ramsar site in India. Materials and methods. AAS studies were employed to estimate metal (Cr, Mn, Fe, Cu, Zn, and Pb) concentrations in water, and bottom sediment of fishponds and fish tissues (gill, liver, muscle, and bones) of cichlids: Nile tilapia, Oreochromis niloticus L. and Mozambique tilapia, O. mossambicus (Peters, 1852), collected from contaminated and control sites. Results. The concentrations of metals in bottom sediment were found higher than those of the overlying water. It was evident from the experiment that, either bone or liver was the site of maximum accumulation for the elements while muscles were the site of least metal accumulation in both fish species. Chromium, which was a highly publicised contaminant of tannery effluents, showed a similar distribution pattern (muscle < gill < liver < bone) in these fishes. Concentrations of non-essential metals like Pb were highest in Nile tilapia liver (17.9 mg • kg-1) followed by Mozambique tilapia liver (14.7 mg • kg-1). Principal component analysis with Varimax rotation revealed that Fe and Mn were in the first and second component, respectively, to influence metal uptake and bioaccumulation. Conclusion. Tissue-specific and species-specific patterns of metal concentration and partitioning were apparent from our experimentation. Dendrograms showed two definite clustering pattern, gill and muscle in one cluster with bone and liver in the other, two important organs so far as partitioning (in bone) and detoxification (in liver) were concerned.