Species delimitation in annual killifishes from the Brazilian Caatinga,the Hypsolebias flavicaudatus complex (Cyprinodontiformes: Rivulidae): implications for taxonomy and conservation

The organisms investigated are members of the Hypsolebias flavicaudatus species complex; a clade of morphologically similar annual killifishes endemic to the semi-arid savannah of north-eastern Brazil in the São Francisco River basin, which is a tropical area under intensive process of habitat loss. A taxonomic revision was conducted combining two different approaches for species delimitation – a tree-based approach using mt-DNA (cytochrome b) and a character-based approach using morphological variation (colour patterns, fin morphology, meristic and morphometric data). Nine species are recognised, of which five are new species: H. flagellatus (Costa), H. flavicaudatus (Costa & Brasil), H. gilbertobrasili sp. nov., H. guanambi (Costa & Amorim), H. janaubensis (Costa), H. nitens sp. nov., H. pterophyllus sp. nov., H. radiseriatus sp. nov. and H. sertanejo sp. nov. On the basis of 17 years of field studies, preliminary conservation status assessments indicate that two species are highly threatened with extinction, at least one is endangered and another is vulnerable, whereas the others are not endangered. This result deeply contrasts with a previous assessment 10 years ago, when the whole H. flavicaudatus complex was considered as a single species of no conservation concern. Discrepancies in the assessment of conservation among closely related species living in similar habitats are a consequence of heterogeneous human occupation and disproportionate recent development throughout the São Francisco River basin.     

Jenynsia lineata species complex,revision and new species description (Cyprinodontiformes: Anablepidae)

The Jenynsia lineata species complex comprises J. lineata from Montevideo, Uruguay and Jenynsia multidentata, from coastal basins of Brazil, Uruguay and Argentina up to 1200 m a.s.l. Taxonomic divisions within this group were tested using three different species delimitation methods, which found the two existing names to be synonyms and revealed a new cryptic species. Jenynsia darwini sp. nov. is distinguished from all congeners by having a unique combination of character states, including the shape of the dorsal postcleithrum (three times higher than wide v. less than two times higher than wide) and female colour pattern in the half of the caudal peduncle with rows of chromatophores segmented in unaligned spots (v. aligned spots forming lines). The new species also differs from J. lineata by having 26 nucleotide substitutions in the mitochondrial gene cytochrome c oxidase I (coI). Phylogenetic analysis of the genus based on morphological characters proposed by previous studies corroborates monophyly of the subgenera Plesiojenynsia and Jenynsia, with the new species being allocated to the subgenus Jenynsia as the sister group of J. lineata.     

High levels of mitochondrial cytochrome b divergence in annual killifishes of the genus Cynolebias (Cyprinodontiformes, Rivulidae)

Phylogenetic relationships based on 324 base pairs of the mitochondrial cytochrome b gene were examined in 14 species of the genus Cynolebias. The monophyly of the genus relative to three outgroup taxa belonging to the family Rivulidae was supported by the sequence data. Bootstrap values corroborated the existence of intrageneric monophyletic units in both parsimony and Neighbour-joining analyses. These include a Cynolebias bellottii-C. wolterstorffl clade, a C. adloJfi-2, C. duraznensis, C. viarius and C adloffi-1 group, and a C. gymnoventris, C. luteoflammulatus pair and the strongly supported assemblage that includes C. prognalhus and C. cheradophilus clade. Phylogenetic relationships remain poorly supported for C. nigripinnis, C. qffinis and C. alexandri, and unresolved among the previous ingroup clades. Cytochrome b sequences reveal an unexpectedly high level of divergence among species of the genus Cynolebias. Consequently, cytochrome b shows good resolution of recent cladogenetic events but limited phylogenetic information at deeper nodes. High levels of sequence divergence span a broad range within Cynolebias. The highest sequence divergence (c. 28%) occurred among C. antenori and the remaining species of the genus. The minimum divergence value (4.5%) is exhibited by sympatric species C. cheradophilus and C. prognathus.     

Phylogenetic relationships of Simpsonichthys subgenera (Cyprinodontiformes,Rivulidae), including a proposal for a new genus

The systematic knowledge of Simpsonichthys has changed substantially in recent years, with five subgenera having been elevated to the genus category. In view of these taxonomic changes, the aim of the present study was to identify the phylogenetic relationships among this group in order to test a hypothesis of the division of Simpsonichthys. The ATPase 8 and 6 gene sequences of 53 specimens of Simpsonichthys, Xenurolebias, Ophthalmolebias, Spectrolebias and Hypsolebias genera were assessed. The final topology divided the Simpsonichthys subgenera into five clades: clade I (Hypsolebias antenori group and Ophtalmolebias), clade II (Simpsonichtys and Spectrolebias), clade III (Hypsolebias flammeus and H. magnificus groups), clade IV (H. notatus group) and clade V, which included the Xenurolebias genus as a sister group to all the other Simpsonichthys subgenera. Simpsonichthys, Spectrolebias and Hypsolebias could therefor not be described as monophyletic groups, as has been proposed in some hypotheses. The H. antenori, H. notatus and H. magnificus groups, however, were monophyletic. The molecular results also suggested that H. ocellatus belongs to the Hypsolebias flammeus group. The phylogenetic position of H. fasciatus suggested a new group within Hypsolebias, or possibly even a new genus. The characteristics of the Hypsolebias antenori group and their phylogenetic position suggested that only the species of this group should be included in the Hypsolebias genus. The basal position of the Hypsolebias notatus group and its morphological character may represent a new genus. Although the monophyletism of Simpsonichtys could not be recovered, the branches supported the division of the western and eastern clades, possibly due to allopatric speciation. These facts suggest the division of the genus into at least two major clades. In addition, the study of morphological and molecular data is suggested to obtain a better understanding of such complex organisms, and a major taxonomic review is required.     

Monophyly and taxonomy of the Neotropical seasonal killifish genus Leptolebias (Teleostei: Aplocheiloidei: Rivulidae), with the description of a new genus

A phylogenetic analysis based on morphological characters indicates that Leptolebias Myers, 1952, a genus of small killifishes highly threatened with extinction, from Brazil, is paraphyletic. As a consequence, Leptolebias is restricted in this study to a well‐supported clade that includes Leptolebias marmoratus (Ladiges, 1934), Leptolebias splendens (Myers, 1942), Leptolebias opalescens (Myers, 1942), and Leptolebias citrinipinnis ( Costa, Lacerda & Tanizaki, 1988 ), from the coastal plains of Rio de Janeiro, and Leptolebias aureoguttatus ( Cruz, 1974 ) (herein redescribed, and for which a lectotype is designated) and Leptolebias itanhaensis sp. nov. , from the coastal plains of São Paulo and Paraná, in southern Brazil.Leptolebias is diagnosed by three synapomorphies: a caudal fin that is longer than deep, a single anterior supraorbital neuromast, and dark pigmentation that does not extend to the distal portion of the dorsal fin in males. A key is provided for the identification of species of Leptolebias. Three species formerly placed in Leptolebias, Leptolebias minimus (Myers, 1942), Leptolebias fractifasciatus ( Costa, 1988 ), and Leptolebias cruzi ( Costa, 1988 ), are transferred to Notholebias gen. nov. , which is hypothesized to be the sister group to the clade comprising Leptolebias, Campellolebias Vaz‐Ferreira & Sierra, 1974, and Cynopoecilus Regan, 1912. Notholebias gen nov. is diagnosed by two synapomorphies: a narrow basihyal and the presence of iridescent bars on the caudal fin in males; and three features interpreted as plesiomorphic, but not occurring in Leptolebias, Campellolebias, or Cynopoecilus, the presence of dermosphenotic, well‐developed contact organs on the pectoral fin in males, and an opercular region with red bars in males. ‘Leptolebias’leitaoi, a species from Bahia, in north‐eastern Brazil, is considered as having an uncertain phylogenetic position, as all known preserved material is presently lost, and the species may be extinct. © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society, 2008, 153 , 147–160.     

Osteological analysis of the killifish genus Cynolebias (Cyprinodontiformes: Rivulidae)

Relationships among the species of the annual fish Cynolebias are unclear. An analysis of the variation and utility of osteological characters for phylogenetic analysis was done using cleared and double-stained specimens representing 21 species of Cynolebias. This analysis showed that some of the characters previously used to diagnose this genus and some of the species are polymorphic. Osteologically, Cynolebias can be diagnosed by the following synapomorphies: (1) triangular-shaped parietal, (2) vomer positioned ventral to the parasphenoid, (3) long ventral process of the dentary, (4) teeth on fourth ceratobranchial, and (5) teeth on first epibranchial. In addition, characters that help define some of the currently recognized species complexes were identified. Species in the “antenori complex” share at least five synapomorphies, such as ossified medial radials of dorsal and anal fins, four pectoral radials, ventral process of the maxillae enlarged, mesopterygoid long relative to the autopalatine, and proportion of cartilage in the basihyal. The “bellottii complex” is characterized by having a reduced basihyal and a deep urohyal, whereas species in the “elongatus complex” possess a caudal fin supported by four vertebrae and have unique modifications of jaw bones. The following osteological features are useful as diagnostic characters at the specific level: (1) Two vertebrae supporting the caudal fin (C. nigripinnis); (2) cartilaginous pelvic bones (C. notatus); (3) short third postcleithrum and broad lateral process of the sphenotic (C. wolterstorffi); (4) thick third postcleithrum (C. gymnoventris); (5) crest on the parietal and reduced in the upper portion of the lacrimal (C. whitei); (6) anteriorly curved lacrimal (C. cheradophilus); (7) second dermosphenotic (C. bellottii); and (8) expansion of the ventral tip of the maxillae and long basyhial (C. constanciae). J. Morphol. 238:245–262, 1998. © 1998 Wiley-Liss, Inc.     

Comparative morphology,phylogenetic relationships,and historical biogeography of plesiolebiasine seasonal killifishes (Teleostei: Cyprinodontiformes: Rivulidae)

Phylogenetic and biogeographical analyses were performed for the Plesiolebiasini, a group of 20 small and rare species of South American annual killifishes, some threatened with extinction, occurring in river basins of Brazil, Bolivia, Paraguay, and Argentina. The results of a maximum parsimony analysis of 142 morphological characters highly corroborate monophyly of the Plesiolebiasini. Monophyly of each plesiolebiasine genus is supported and Plesiolebias is hypothesized to be the sister group to a clade comprising the remaining plesiolebiasine genera (Papiliolebias, Pituna, Maratecoara, and Stenolebias), corroborating studies based on mitochondrial genes. The phylogenetic analysis supports sister group relationships between Papiliolebias and the clade containing Pituna, Maratecoara, and Stenolebias, and between Maratecoara and Stenolebias. The biogeographical analysis indicates a complex historical biogeographical scenario for plesiolebiasines. A vicariance event between the western Paraguay area and northern river basins may be related to the isolation of the Chaco region from the Amazon between the Late Oligocene and Early Miocene. A vicariance event involving the Paraguay River basin and northern rivers, and the multiple occurrence of area hybridism along the Araguaia depression are tentatively identified as a consequence of tectonic subsidence events occurring during the Pleistocene. © 2011 The Linnean Society of London, Zoological Journal of the Linnean Society, 2011, 162 , 131–148.     

Mitochondrial genes: signals and noise in the phylogenetic reconstruction of the annual killifish genus Cynolebias (Cyprinodontiformes, Rivulidae)

The genus Cynolebias (Cyprinodontiformes: Rivulidae) is a locally endemic and speciose group of Neotropical fishes with an annual life cycle. Members of the genus vary greatly in morphology and behaviour, and extensive interspecific karyotypic divergence has been documented among species from Uruguay, Argentina and Rio Grande do Sul, Brazil. We present a molecular systematic hypothesis of the relationships between these Cynolebias species based on phylogenetic analysis of a combined dataset containing 1825 base pairs of DNA sequence, representing three mitochondrial genes. The protein-coding cytochrome -b gene, the 12S and 16S rRNA mitochondrial genes, alone and in combination, yield robust support for monophyly within Cynolebias . Furthermore, our analyses identify two major Cynolebias clades, one of which contains at least four monophyletic groups. Corrected mtDNA genetic distances range from 5.2 to 17.5% between Cynolebias species, and application of a molecular clock suggests the occurrence of two pulses of cladogenesis, one in the late Miocene and another in the Pliocene–Pleistocene. © 2002 The Linnean Society of London, Biological Journal of the Linnean Society , 2002, 76 , 49–59.     

Genetic Differentiation Among Annual Fishes of the Genus Cynolebias (Cyprinodontiformes, Rivuluidae) in a Biosphere Reserve Site from Uruguay

The annual killifishes of the genus Cynolebias include one well supported clade composed of three taxa: Cynolebias adloffi, from Porto Alegre (southern Brazil), C. cf. adloffi and Cynolebias viarius, parapatrically distributed in southeastern Uruguay. Cynolebias cf. adloffi has always been considered an intergradation complex of populations between C. adloffi and C. viarius showing high levels of morphological variability and its systematic affinities have been historically discussed. This study clarified the patterns of genetic differentiation of C. cf. adloffi by means of RAPD markers to define its taxonomic status as a possible separated taxon. Multidimensional scaling analysis reveals that C. cf. adloffi is composed of two highly structured genetic groups (northern and southern) with discrete geographical distributions. The estimate of gene diversity for RAPD markers could suggest a scenario in which the rainy season flood pool populations across large distances could make intrapopulation variation high but interpopulation variation low. Phylogenetic analyses (UPGMA and parsimony) show different and unstable patterns of relationships among the taxa analyzed. In the UPGMA tree, C. viarius and C. cf. adloffi appear as sister taxa, while parsimony analysis does not support a unique hypothesis of relationship. Our analyses are in agreement with the hypothesis that C. cf. adloffi may well be a case of ancient hybrid ancestry followed by its divergence associated with Pleistocene and post-Pleistocene environmental changes in this region.     

A phylogenetic analysis of the palm subtribe Oncospermatinae (Arecaceae) based on morphological characters

Subtribe Oncospermatinae (Arecaceae: Arecoideae: Areceae) is a diverse group of spiny Old World palms. The subtribe includesOncosperma, a widespread Asian genus of five species, along with seven monotypic genera, all endemic to the Seychelles and Mascarene Islands of the western Indian Ocean. A phylogenetic analysis was conducted in order to test the monophyly of subtribe Oncospermatinae with respect to other Old World genera of tribe Areceae. A matrix of 38 morphological characters was scored for 29 taxa, including 11 species of the Oncospermatinae. A single most parsimonious tree was found, resolving the subtribe as a polyphyletic group of two distinct clades. One clade containingAcanthophoenix, Deckenia, Oncosperma, andTectiphiala was placed as sister to a large group that includes members of subtribes Archontophoenicinae, Arecinae, Iguanurinae, and Ptychospermatinae. The other clade of Oncospermatinae, including the Seychelles endemic generaNephrosperma, Phoenicophorium, Roscheria, andVerschaffeltia, was resolved as sister to the Madagascar endemic subtribe Masoalinae, and may have arisen in the western Indian Ocean region.     

A new species of the neotropical annual fish genus Pterolebias (Cyprinodontiformes, Rivulidae), from Central Brazil

A new species of Pterolebias from Caceres, Paraguay River Basin, State of Mato Grosso, Brazil, is described. It was found in a temporary lagoon on the Brazilian Central Cerrado and seems to have the same annual habits of the other species of the group. The new species differs from all other species but P. staeckiin the colour pattern on the sides of the body, which consists of longitudinal stripes. From P. siaecki it differs in the relative length of the pelvic-fin and of the predorsal area and by the number of scales in the longitudinal series. The similarity between P. bokermanni and P. longipinnis is discussed.     

Filling the gaps: phylogeography of the self-fertilizing Kryptolebias species (Cyprinodontiformes: Rivulidae) along South American mangroves

Mangrove killifishes of the genus Kryptolebias have been historically classified as rare because of their small size and cryptic nature. Major gaps in distribution knowledge across mangrove areas, particularly in South America, challenge the understanding of the taxonomic status, biogeographical patterns and genetic structuring of the lineages composing the self-fertilizing “Kryptolebias marmoratus species complex.” In this study, the authors combined a literature survey, fieldwork and molecular data to fill major gaps of information about the distribution of mangrove killifishes across western Atlantic mangroves. They found that selfing mangrove killifishes are ubiquitously distributed across the Caribbean, Central and South American mangroves and report 14 new locations in South America, extending the range of both the “Central clade” and “Southern clade” lineages which overlap in the Amazon. Although substantial genetic differences were found between clades, the authors also found further genetic structuring within clades, with populations in Central America, north and northeast Brazil generally showing higher levels of genetic diversity compared to the clonal ones in southeast Brazil. The authors discuss the taxonomic status and update the geographical distribution of the Central and Southern clades, as well as potential dispersal routes and biogeographical barriers influencing the distribution of the selfing mangrove killifishes in the western Atlantic mangroves.     

A phylogenetic analysis of subtribe Pleurothallidinae (Orchidaceae)

A cladistic analysis of subtribe, Pleurothallidinae (Orchidaceae) is based on 45 anatomical/ morphological characters. The ingroup members comprise 24 genera; the large genus Pleurothallis consists of two subgenera and ten species complexes. Three taxa representing subtribes Laeliinae and Arpophyllinae are designated as outgroup. Eight most parsimonious trees were discovered using computer assisted software (length = 230; CI = 0.27). The hypothesis that subtribe Pleurothallidinae has undergone a unilinear reduction in the number of pollinia is not supported by this study. Although the eight-pollinia state as represented by Octomeria apparently is plesiomorphic, the two-pollinia and four-pollinia states arose early in the phylogeny of the subtribe. Both two-and four-pollinia states subsequently reappeared as parallelisms. The six-pollinia state exhibited in Brachionidium is autapomorphic. This cladistic analysis suggests that Pleurothallis is not a natural genus and, perhaps may be divided into several discrete genera.     

A phylogenetic analysis of subtribe Pleurothallidinae (Orchidaceae)

A cladistic analysis of subtribe, Pleurothallidinae (Orchidaceae) is based on 45 anatomical/ morphological characters. The ingroup members comprise 24 genera; the large genus Pkurothallis consists of two subgenera and ten species complexes. Three taxa representing subtribes Laeliinae and ArpophyUinae are designated as outgroup. Eight most parsimonious trees were discovered using computer assisted software (length = 230; CI = 0.27). The hypothesis that subtribe Pleurothallidinae has undergone a unilinear reduction in the number of pollinia is not supported by this study. Although the eight-pollinia state as represented by Octomeria apparently is plesiomorphic, the two-pollinia and four-pollinia states arose early in the phytogeny of the subtribe. Both two-and four-pollinia states subsequently reappeared as parallelisms. The six-pollinia state exhibited in Brachionidium is autapomorphic. This cladistic analysis suggests that Pkurothallis is not a natural genus and, perhaps may be divided into several discrete genera.     

Description of a new species of Wormaldia from Sardinia and a new Drusus species from the Western Balkans (Trichoptera,Philopotamidae, Limnephilidae)

New species are described in the genera Wormaldia (Trichoptera, Philopotamidae) and Drusus (Trichoptera, Limnephilidae, Drusinae). Additionally, the larva of the new species Drusus crenophylax sp. n. is described, and a key provided to larval Drusus species of the bosnicus-group, in which the new species belongs. Observations on the threats to regional freshwater biodiversity and caddisfly endemism are discussed.The new species Wormaldia sarda sp. n. is an endemic of the Tyrrhenian island of Sardinia and differs most conspicuously from its congeners in the shape of segment X, which is trilobate in lateral view. The new species Drusus crenophylax sp. n. is a micro-endemic of the Western Balkans, and increases the endemism rate of Balkan Drusinae to 79% of 39 species. Compared to other Western Balkan Drusus, males of the new species are morphologically most similar to Drusus discophorus Radovanovic and Drusus vernonensis Malicky, but differ in the shape of superior and intermediate appendages. The females of Drusus crenophylax sp. n. are most similar to those of Drusus vernonensis, but differ distinctly in the outline of segment X. Larvae of Drusus crenophylax sp. n. exhibit toothless mandibles, indicating a scraping grazing-feeding ecology.     

Cetopsis varii,a new species of whale catfish (Siluriformes: Cetopsidae) from the Meta Basin,Colombia

Cetopsis varii sp. nov. Cetopsidae (Cetopsinae) is described from the Río Meta basin in eastern Colombia, at middle portions of the Río Orinoco basin. The new species differs from congeners by a combination of features: the absence of a humeral spot, presence of eye, conical teeth on vomer and dentary and rounded posterior nares, along with details of body, dorsal and caudal‐fin pigmentation. The osteology of the new species is investigated through high‐resolution X‐ray computed tomography and cleared and stained specimens. Data thus obtained are used to code the new species for character states utilized in a previous phylogenetic analysis of Cetopsidae. Analysis of the expanded matrix shows that C. varii is the sister group to C. orinoco.     

Multiple simultaneous speciation in killifishes of the Cynolebias adloffi species complex (Cyprinodontiformes, Rivulidae) from phylogeography and chromosome data

The annual killifishes of the genus Cynolebias Steindachner, 1876, include one of the well-supported clades composed of the Cynolebias adloffi species complex of the Bañados del Este Biosphere Reserve Site, from the Atlantic coastal wetlands in Uruguay. One member of this clade, Cynolebias charrua , has been considered as an intergradation complex of populations between C. adloffi and C. viarius by showing high levels of morphological variability. Systematic affinities between both taxa have been historically discussed. In the present study, a phylogeographic approach based on mitochondrial cytochrome b haplotype analysis and chromosome data are presented. According to the present data a scenario of a multiple simultaneous speciation process and perhaps reticulation events is possible in the C. adloffi species complex, followed by divergence associated with Quaternary marine transgressions in this region. This hypothetic scenario could explain the remarkable genetic diversity and the lack of phylogenetic resolution among clades in C. charrua , as well as the disconcordance in the phylogenetic relationships among Cynolebias from different data sets. Several parameters of DNA polymorphism and chromosome data have also suggested that populations of C. charrua from southern Laguna Merin, in eastern Uruguay and southern Brazil, could represent a relictual group from a widespread ancestral population. Chromosome rearrangements like pericentric inversions in isolated populations could have triggered cladogenetic events from this highly polymorphic population. Present analysis suggests that the metapopulation could represent the management units in these endangered killifishes and that the populations of C. charrua from the Laguna Merin basin could be included in a high-priority conservation programme.     

Taxonomic revision, phylogenetic analysis, and biogeography of the bee genus Tropidopedia (Hymenoptera, Apidae, Tapinotaspidini)

The species of the bee genus Tropidopedia stat. nov. are revised. Thirteen new species are proposed: T. carinata sp. nov. , T. caracicola sp. nov. , T. danunciae sp. nov. , T. duckeana sp. nov. , T. eliasi sp. nov. , T. flavolineata sp. nov. , T. friesei sp. nov. , T. japuraensis sp. nov. , T. nigrita sp. nov. , T. nigrocarinata sp. nov. , T. ornata sp. nov. , T. peruana sp. nov. and T. venezuelana sp. nov. Taxonomic notes are provided for another four species: Tropidopedia punctifrons (Smith, 1879) comb. nov. , T. pallidipennis (Friese, 1899) comb. nov. , T. seabrai (Michener & Moure, 1957) and T. arcuatilis (Vachal, 1909) comb. nov. , including designation of a lectotype for Tetrapedia arcuatilis Vachal. An identification key, illustrations for main diagnostic characters, and distributions maps for all species are provided. A phylogenetic analysis was carried out to evaluate the monophyly of Tropidopedia and its main species groups, as well as to position it among the related genera. Biogeographical patterns are discussed.  © 2007 The Linnean Society of London, Zoological Journal of the Linnean Society , 2007, 151 , 511–554.     

Egg surface structure in the annual fishes Simpsonichthys (subgenera Ophthalmolebias and Xenurolebias) and Nematolebias (Teleostei: Cyprinodontiformes: Rivulidae): variability and phylogenetic significance

The surfaces of the egg chorion of nine species of Simpsonichthys , two of Nematolebias and eight other species of rivulids were studied with scanning electron microscopy revealing details of ornamentation that were previously undocumented. Surface structures of eggs of Simpsonichthys of the subgenus Ophthalmolebias are described for the first time: eggs of Simpsonichthys constanciae , Simpsonichthys perpendicularis , Simpsonichthys rosaceus and Simpsonichthys suzarti are ornamented with a very characteristic palm-like structure, that is restricted to these species among the rivulids examined. The surface of the egg chorion of Simpsonichthys bokermanni lacks the well-developed palm-like structure, but has a characteristic conical projection, distinct from the structures of other rivulids examined, that is proposed as homologous to the palm-like structure. Simpsonichthys bokermanni shares with Nematolebias papilliferus and Nematolebias whitei the presence of concentric rows of spiny projections around the micropylar region. Species of Simpsonichthys of the subgenus Ophthalmolebias , Simpsonichthys myersi (of the subgenus Xenurolebias ), and N. whitei share the presence of large rounded protuberances on the surface of the egg chorion. The phylogenetic significance of these features are evaluated and discussed in light of current knowledge about rivulid relationships.