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Revised Procedures For Staining And Clearing Small Fishes And Other Vertebrates For Bone And Cartilage Study
... Measurements are presented as proportions of standard length, except for subunits of the head, which are presented as proportions of head length. Counts of vertebrae and supraneurals were taken from a single cleared and stained specimen (CS) prepared according to Taylor & Van Dyke (1985). Total vertebral count includes the Weberian apparatus, counted as four elements, and the preural centrum 1 plus ural centrum 1 (PU1+U1) of the caudal region was counted as a single vertebral element. ...
Hyphessobrycon scholzei Ahl, the black line tetra, or “Schwarzbandsalmler”, is a well-known tetra in the aquarium hobby, said to be originated from the lower Amazon basin in Pará state, Brazil. The species was for decades common in the aquarium hobby due to the easiness in its maintenance and breeding but reports of wild specimens were few and dubious. Hyphessobrycon fernandezi Fernández-Yépez was described from the río Yaracuy, an independent coastal drainage in northern Venezuela, and is only known from this and some adjacent small coastal river drainages, and the río Portuguesa drainage, río Orinoco basin. Based on morphological data, we herein argue that H. fernandezi is a junior synonym of H. scholzei. Circumstantial evidence herein assembled supports the idea that the purported type locality of H. scholzei is incorrect and that its type material, as well as the original stock that originated the aquarium population of the species, was very likely collected at the same occasion as the first specimens of Moenkhausia pittieri introduced in the aquarium hobby. We also discuss the conservation status of the species as well as its apparent demise from the aquarium hobby.
... In the text and tables, SD is used for standard deviation. Counts of vertebrae, supraneurals, teeth, gill-rakers, procurrent caudal-fin rays, and information about osteological characters were obtained from specimens cleared and double stained for cartilage and bone (c&s) following the protocol of Taylor & Van Dyke (1985). Total number of vertebrae includes the four vertebrae of the Weberian apparatus counted as separate elements, all post Weberian vertebrae including the compound ural centrum, which was counted as a single vertebra. ...
The miniature fish genus Priocharax currently comprises nine valid species: P. ariel, P. britzi, P. conwayi, P. marupiara, P. nanus, P. phasma, P. pygmaeus, P. toledopizae and P. varii. Except for P. ariel and P. pygmaeus, all remaining species are endemic to Brazil. Priocharax is characterized by several paedomorphic features such as reductions in the laterosensory system, number of fin rays, and ossification of parts of the skull. The most striking reductive character of Priocharax is the larval rayless pectoral fin in which most of its endoskeletal part is absent. A new species of Priocharax is described herein from the río Putumayo drainage, Departamento Amazonas, Colombia. The new species is distinguished from all other congeners by a unique round flap of skin between contralateral pelvic fins.
... Before conducting SEM, the epicuticle tissue from the skeleton was dissolved using a proteolytic enzyme to observe the underlying crystalline layers. We used the method described by Tiago, Brites, and Kawauchi (2005), which is based on clearing muscle tissues with the proteolytic enzymes in a borax buffer described in Taylor and Van Dyke (1985). Such a procedure was undertaken to make sure that fragile larvae were rendered in their initial form and no extra dissolution was imposed on the exoskeleton ( Figure S2). ...
Anthropogenic carbon dioxide emissions have been increasing rapidly in recent years, driving pH and oxygen levels to record low concentrations in the oceans. Eastern boundary upwelling systems such as the California Current System (CCS) experience exacerbated ocean acidification and hypoxia (OAH) due to the physical and chemical properties of the transported deeper waters. Research efforts have significantly increased in recent years to investigate the deleterious effects of climate change on marine species, but have not focused on the impacts of simultaneous OAH stressor exposure. Additionally, few studies have explored the physiological impacts of these environmental stressors on the earliest life stages, which are more vulnerable and represent natural population bottlenecks in organismal life cycles. The physiological response of the ecologically and commercially important red sea urchin ( Mesocentrotus franciscanus ) was assessed by exposing larvae to a variety of OAH conditions, mimicking the range of ecologically relevant conditions encountered currently and in the near future along the CCS. Skeleton dissolution, larval development, and gene expression show a response with clearly delineated thresholds that were related to OAH severity. Skeletal dissolution and the induction of Acid‐sensing Ion Channel 1A at pH 7.94/5.70 DO mg/L provide particularly sensitive markers of OAH, with dramatic shifts in larval morphology and gene expression detected at the pH/DO transition of 7.71/3.71–7.27/2.72 mg/L. Experimental simulations that describe physiological thresholds and establish molecular markers of OAH exposure will provide fishery management with the tools to predict patterns of larval recruitment and forecast population dynamics.
... Morphometric characters were extracted using ImageJ (Schneider et al., 2012) and standardized relative to their relationship with standard length (SL) or head length (HL) in the case of orbit diameter. The clear and stained method by Taylor and van Dyke (1985) was followed. ...
This study offers a comprehensive analysis and detailed description of the fossil fish assemblage from the Pleistocene Laguna Formation in Luzon Island, Philippines. The fish fossils were collected from the deeper lacustrine facies of the formation, and a total of three fish families were identified. The identification is based on the recognizable synapomorphies in 10 moderately preserved semi-articulated individuals of ray-finned fish specimens, some of which include counterparts. The assemblage is predominantly composed of small clupeiforms of the family Dorosomatidae, accompanied by a gobioid fish (Gobiidae or Oxudercidae) and a synbranchid specimen (Synbranchidae), each represented by a single specimen. This taphocoenosis preserves free-swimming dorosomatids and demersal gobioid and synbranchid, suggesting an autochthonous assemblage with minimal postmortem sorting. Despite all recognized taxa being tolerant to changes in salinity, the environment is inferred to have been freshwater, analogous to modern Taal Lake, where a freshwater sardine thrives. This study represents the first systematic description of freshwater fish fossils in the Philippines and marks the first discovery of these taxa in the tropical West Pacific region.
... Morphometric characters were extracted using ImageJ (Schneider et al., 2012) and standardized relative to their relationship with standard length (SL) or head length (HL) in the case of orbit diameter. The clear and stained method by Taylor & van Dyke (1985) was followed. ...
This study offers a comprehensive analysis and detailed description of the fossil fish assemblage from the Pleistocene Laguna Formation in Luzon Island, Philippines. The fish fossils were collected from the deeper lacustrine facies of the formation, and a total of three fish families were identified. The identification is based on the recognizable synapomorphies in 10 moderately preserved semi-articulated individuals of ray-finned fish specimens, some of which include counterparts. The assemblage is predominantly composed of small clupeiforms of the family Dorosomatidae, accompanied by a gobioid fish (Gobiidae or Oxudercidae) and a synbranchid specimen (Synbranchidae), each represented by a single specimen. This taphocoenosis preserves free-swimming dorosomatids and demersal gobioid and synbranchid, suggesting an autochthonous assemblage with minimal postmortem sorting. Despite all recognized taxa being tolerant to changes in salinity, the environment is inferred to have been freshwater, analogous to modern Taal Lake, where a freshwater sardine thrives. This study represents the first systematic description of freshwater fish fossils in the Philippines and marks the first discovery of these taxa in the tropical West Pacific region.
... Morphometrics are given as percentages of standard length (SL), except for subunits of the head, which are expressed as percentages of head length (HL). Specimens were cleared and stained (c&s) according to Taylor & Van Dyke (1985). The number of branchiostegals, gill rakers, vertebrae, ribs, and supporting elements of dorsal and anal fins positions were determined in cleared and stained specimens. ...
Heptapteridae is a group of small to medium-sized neotropical catfish composed of 23 genera and 238 valid species, classified into two subfamilies: Rhamdiinae and Heptapterinae. Phenacorhamdia represents small heptapterids and is composed of 14 valid species distributed across all major river basins in South America. In this paper, we add another species to the genus, described from the Juruena River basin, Mato Grosso state, Central Brazil. This species is distinguished from its congeners by having multicuspid teeth, 47–52 vertebrae, maxillary barbel not reaching to pectoral-fin origin, and absence of a short extension of the first pectoral-fin ray. Additionally, a brief discussion on its putative phylogenetic position, based on UCEs dataset, is provided.
... The specimens were then fixed in 10% formaldehyde (not buffered) for 48 h and dehydrated in an increasing alcohol series. To distinguish between the ossified/mineralized and cartilaginous portions, we adapted the clearing and double staining method described by Taylor and Van Dyke (1985), using the enzyme pancreatin for the digestion of soft tissues (i.e., muscles). The mineralized regions within bone tissue were clearly distinguishable by different shades and intensities of red (stained by Alizarin Red), and the stillcartilaginous portions were distinguishable by shades of blue (stained by Alcian Blue). ...
Analyzing the degree of mineralization can be an excellent tool for evaluating the effects of stressors. Biomarkers that detect sublethal effects on bone structures are highly applicable. The present study proposes to review the categorization technique and apply it to long bones by using four categories to investigate the mineralization of long bones in recently metamorphosed anurans, demonstrating its applicability and efficiency in ecotoxicological studies. The technique involves double staining of bones to differentiate between mineralized and cartilaginous tissues, followed by observation under a stereomicroscope. We used as an applicability model a study of exposure to the insecticide fipronil in two native species, Leptodactylus fuscus (whistling frog) and Scinax fuscovarius (snouted tree frog). To validate the proposed way of application, we also carried out a more complex quantitative analysis and compared the results. We defined four categories that reflected the ossification process during metamorphosis. When applied in the experimental design, these categories proved highly effective in highlighting the effect of the tested contaminant on mineralization. Comparing the results of the proposed methodology with the quantitative analysis showed that both yielded similar outcomes. Thus, assessing the degree of mineralization through the proposed way of analysis is highly applicable and effective and has great potential for analyzing vertebrates’ long bones.
... Select specimens were reversibly stained using cyanine blue following Saruwatari et al. (1997) to aid examination of adhesive disc papillae, genital papillae, and cephalic lateral line canal pores. Select specimens were cleared and double stained (CS) for bone and cartilage investigation using the protocol of Taylor & van dyke (1985). Specimens or parts thereof were observed and photographed using a ZEISS SterEO discovery v20 stereomicroscope equipped with a ZEISS Axiovision software. ...
A new genus and four new species of clingfishes are described based on specimens collected primarily from seagrass along the southern coast of Australia. The new genus Melanophorichthys is distinguished from all other genera of the Gobiesocidae by aspects of colour pattern, including the presence of numerous, large, dark brown to black melanophores along the side of the body in adults, and sexually dimorphic and dichromatic dorsal and anal fins, larger and more colourful (in life) in males. Melanophorichthys posidonus, type species of Melanophorichthys, is described based on 17 specimens (24.6–35.0 mm SL) from South Australia and Victoria. Melanophorichthys priscillae is described based on 119 specimens (16.4–34.0 mm SL) from Western Australia. Melanophorichthys parvipsittus is described based on 73 specimens (16.2–24.6 mm SL) from Victoria and Tasmania. Melanophorichthys penicillus is described based on 10 specimens (17.0–26.0 mm SL) from Western Australia. The new species are distinguished from each other by characters of body shape, head shape, vertebrae and fin-ray counts, features of osteology, and aspects of live colour pattern. Based on available phylogenetic hypotheses for the Gobiesocidae, the new genus represents the sister taxon to a clade comprising two other clingfishes of the polyphyletic genus “Cochleoceps”, C. spatula (type species) and C. viridis, that are found primarily in seagrass. Including the four new species, eleven species of clingfish (~5% of Gobiesocidae) are identified as seagrass specialists (i.e., species that occur primarily within seagrass beds or meadows, but may occur rarely in other habitats).
... Morphological terminology, methods to take and describe morphometric and meristic data, selection and sequence pattern of morphological attributes used in species descriptions are according to our most recent taxonomic studies on Trichomycterus (e.g., Costa et al. 2023a), which follow Taylor & Van Dyke (1985) for osteological preparations, Costa (1992), Costa et al. (2020), and Bockmann & Sazima (2004) for taking morphometric and meristic data, Costa (2021) and Kubicek (2022) for osteological nomenclature, and Arratia & Huaquin (1995) and Bockmann & Sazima (2004) for latero-sensory pore nomenclature. ...
Streams in the Atlantic Forest of Brazil are home to a great diversity of endemic freshwater fishes, but some fish groups are still poorly known. In the last 22 years, our field inventories have recorded some species of the mountain catfish genus Trichomycterus that are endemic to the Rio Itabapoana Basin, among which two were not still described. Herein, we provide formal descriptions for these two species. One of these species is a member of the NMM-clade of the subgenus Cryptocambeva and the other one belongs to the beta-clade of the subgenus Psammocambeva. Both species are diagnosed by an exclusive combination of character states of the external morphology and osteology. This study indicates that the number of endemic trichomycterine species in the Rio Itabapoana Basin, presently five, is larger than in any other small coastal river basin of the Atlantic Forest. A key for identification of species of Trichomycterus from this basin is provided. We discuss two factors that may be responsible for the relatively high concentration of trichomycterines in this basin: streams draining separate mountain ranges or possible past connections with two neighbouring larger basins, the Rio Doce and the Rio Paraíba do Sul basins.
... Frequency of each count is provided in parentheses after the respective count; asterisks indicate holotype values. Counts of vertebrae, supraneurals, procurrent caudal-fin rays, teeth and teeth cusps, and gill rakers of the first arch were taken from two cleared and stained specimens (c&s) prepared according to Taylor & Van Dyke (1985). Vertebrae of the Weberian apparatus were counted as four elements, and the fused PU1+U1 of the caudal region as a single element. ...
Hyphessobrycon vanzolinii, new species, is described from the rio Tapajós, Amazon basin, Pará state, Brazil. The new species can be diagnosed from all its congeners by its unique color pattern, consisting of a longitudinal, broad, diffuse dark midlateral stripe extending from the snout through the orbit to the base of the middle caudal fin rays, dark pigmentation on the last unbranched ray and first to second branched rays of the dorsal fin, a distal dark stripe along the margin of the anal fin, and the presence of dark pigmentation along the distal margin of the caudal fin. Remarks on the putative relationships of the new species, as well as about the threat posed by a large dam to be build exactly at the only site from where Hyphessobrycon van-zolinii is so far known, are presented. Zusamenfassung Die neue Art Hyphessobrycon vanzolinii wird vom Rio Tapajós, Amazonasbecken, Staat Pará, Brasilien, be-schrieben. Ihre Exemplare lassen sich von allen anderen Angehörigen der Gattung durch die einzigartige Farb-gebung unterscheiden: ein breiter, diffus dunkler Streifen in der Mitte der Flanken, der sich von der Schnauze durch die Augenhöhle bis zur Basis der mittleren Schwanz-flossenstrahlen erstreckt; dunkle Pigmente auf dem letzten unverzweigten Flossenstrahl und dem ersten und zweiten der verzweigten Flossenstrahlen der Rückenflosse; ein dun-kler Streifen am distalen (körperfernen) Rand der After-flosse; sowie dunkle Pigmentierung am distalen Rand der Schwanzflosse. Es folgen einige Bemerkungen über die mutmaßlichen verwandtschaftlichen Beziehungen der neuen Art sowie über ihre Bedrohung durch den Bau eines Dammes, der genau durch das einzige Gebiet ver-laufen soll, von dem Hyphessobrycon vanzolinii bisher bekannt ist. Resumo Hyphessobrycon vanzolinii, espécie nova, é descrita do rio Tapajós, bacia amazônica, estado do Pará, Brasil. A nova espécie pode ser diagnosticada de todos os congêneres por seu padrão de colorido único, que consiste em uma faixa escura ao longo da linha media do corpo larga e difusa, que se extende do focinho à base dos raios medianos da nadadeira caudal, presença de pigmentação escura no últi-mo raio não ramificado e primeiro a segundo raios ramifi-cados da nadadeira dorsal, uma faixa escura ao longo da margem da nadadeira anal, e a presença de pigmentação es-cura ao longo da margem distal da nadadeira caudal. Ob-servações sobre as possíveis relações da espécie nova, bem como sobre a ameaça apresentada por uma grande hidrelétrica a ser construída exatamente sobre a única lo-calidade de onde Hyphessobrycon vanzolinii é até o momen-to conhecida são apresentadas. Résumé Hyphessobrycon vanzolinii, nouvelle espèce, est décrite provenant du Tapajos, bassin de l'Amazonie, état du Para, Brésil. La nouvelle espèce peut être distinguée de tous ses congénères par son patron de coloration unique, composé d'une ligne centrale longitudinale, large, sombre et diffuse, qui s'étend du rostre, par l'orbite, jusqu'à la base des rayons du centre de la caudale, d'une pigmentation foncée sur le dernier rayon non ramifié et du premier au second rayon ramifié de la dorsale, d'une ligne distale foncée le long du bord de l'anale et de la présence d'une pigmentation sombre le long du bord distal de la caudale. Des remarques sur les affinités possibles de la nouvelle espèce ainsi que sur la menace d'un barrage à construire exactement sur le seul site où Hyphessobrycon vanzolinii a été repéré jusqu'ici, sont présentées. aqua vol. 22 no. Sommario Hyphessobrycon vanzolinii, nuova specie, viene descritta dal Rio Tapajós, Amazzonia, nello stato di Pará, Brasile. La nuova specie può essere diagnosticata da tutti i suoi con-generi per la sua tipica colorazione, consistente in un'ampia e diffusa banda longitudinale mediana scura che si estende dal muso attraverso l'orbita fino alla base dei rag-gi della pinna caudale, una pigmentazione scura sull'ulti-mo raggio non ramificato e sui primi due raggi ramificati della pinna dorsale, una striscia scura distale lungo il mar-gine della pinna anale e la presenza di pigmentazione scura lungo il margine distale della pinna caudale. Infine, sono presentate osservazioni sui rapporti putativi della nuova specie, così come sulla minaccia rappresentata da una grande diga da costruire esattamente l'unico sito da cui H. vanzolinii è finora noto.
... Specimens of all Corydoradinae species from NW and southern La Plata basin were cleared and stained (CS) following the Taylor and Van Dyke (1985) protocol (see S1). Osteological terminology is based on Reis (1998a), except in the usage of parieto-supraoccipital instead of supraoccipital (Arratia and Gayet, 1995), compound pterotic instead of pterotic-supracleithrum (Aquino and Schaefer, 2002), and scapulocoracoid instead of coracoid (Lundberg, 1970). Nomenclature of laterosensory canals and preopercular pores are according to Schaefer and Aquino (2000) and Schaefer (1988), respectively. ...
The knowledge about the diversity and phylogeny of South American callichthyid armored catfishes of the sub-family Corydoradinae is still growing, after important recent contributions, and many species have uncertain relationships. In this study, we present the first combined phylogenetic hypothesis for the genus based on five genes, 83 morphological characters, and 153 species, providing synapomorphies for some of the main genera of Corydoradinae, as recently defined. The inclusion of species not previously analyzed in a phylogenetic context challenged the monophyly of Hoplisoma and required the definition of a new genus for endemic species from the Andean portion of the northwestern La Plata basin (ANWLP): Hoplisoma gladysae, Hoplisoma micracanthum, and Hoplisoma petracinii. We found Hoplisoma non monophyletic with Hoplisoma sensu stricto not sister to a clade of species herein named the 'Hoplisoma' paleatum clade. In this clade we recovered a new species of Hoplisoma, which is endemic to the upper Bermejo basin, as sister to 'Hoplisoma' paleatum from the lower La Plata basin. The new species is distinguished from all congeners by a unique coloration similar to that of the syntopic H. micracan-thum, suggesting a putative case of Müllerian co-mimicry.
... Measurements of subunits of heads were given as proportions of dorsal head length (DHL) and lateral head length (LHL). Fin rays were counted under a stereozoom microscope and were confirmed through a cleared and stained specimens following Taylor & Van Dyke (1985). Vertebral counts and description of caudal complex were done from cleared and stained specimens following Sawada (1982). ...
... One specimen of each species was stained with an ethanolbased solution of alizarin red following Springer and David Johnson (2000), for the analysis of scale structures, except for Cyttopsis rosea. One specimen of Allocyttus verrucosus (MNRJ 55192, 122.1 mm SL), Xenolepidichthys dalgleishi (MNRJ 55191, 85.6 mm SL) and Zenion hololepis (MNRJ 53125, 73.4 mm SL) were cleared and stained following Taylor and Van Dyke (1985) for further analysis. We did not access directly sexual dimorphism of the scales, as the specimens were not sexed through direct gonad examination, and the species examined do not possess secondary sexual dimorphism. ...
The order Zeiformes comprises a small order of predominantly deep‐sea fishes. However, little information is available on their morphology, such as squamation. Therefore, in the present study, we analysed and described the squamation pattern and scale morphology of five species of Zeiformes occurring on the Brazilian coast: Allocyttus verrucosus, Grammicolepis brachiusculus, Xenolepidichthys dalgleishi, Zenion hololepis and Zenopsis conchifer. Our analysis revealed greater morphological diversity than previously reported for this order. All species, except the scaleless Zenopsis conchifer, presented cycloid scales of spinoid subtype. Grammicolepis and Zenion presented exclusively scales of the spinoid subtype, whereas both Allocyttus and Xenolepidichthys also displayed true cycloid subtype. A. verrucosus is characterised by two distinct groups of scales of different sizes that form scale clusters. G. brachiusculus and X. dalgleishi presented a unique vertically elongated scale covering most of the body. Small bony plates were observed at the dorsal‐ and anal‐fin bases of G. brachiusculus, X. dalgleishi and Z. hololepis. The variation observed is putatively useful for the systematics of the order.
... 16 Classical staining protocols typically use Alizarin red S for mineralized bone and Alcian blue 8GX for cartilage. 47 However, the acidic nature of Alcian blue can remove minerals from early mineralizing structures, leading to false-negative results. To address this, Walker and Kimmel 48 proposed an acid-free double staining protocol suitable for early skeletal development in zebrafish. ...
Zebrafish and other small laboratory fishes are emerging as important animal models for investigating human skeletal development and diseases. In recent years, there has been a notable increase in research publications employing x-ray radiography and micro-computed tomography to analyze the skeletal structures of these animals. However, evaluating bone morphology and mineral density in small laboratory fish poses unique challenges compared to well-established small rodent models. The varied approaches to image acquisition, analysis, and reporting across studies have led to substantial obstacles in interpreting and comparing research findings.
This article addresses the urgent need for standardized reporting of parameters and methodologies related to image acquisition and analysis, as well as the adoption of harmonized nomenclature. Furthermore, it offers guidance on anatomical terminology, units of measurement, and the establishment of minimal parameters for reporting, along with comprehensive documentation of methods and algorithms used for acquisition and analysis.
We anticipate that adherence to these guidelines will enhance the consistency, reproducibility, and interpretability of reported measurements of bone density and morphometry in small fish models. These advancements are vital for accurately interpreting phenotypes and gene functions, particularly in the context of multi-center studies.
... The larvae were photographed with a portable camera combined with a microscope eyepiece. To find out the bone anlage of skeletal elements, fixed individuals (10 specimens) were stained with alizarin-S, followed by clearing in glycerol, according to standard methods (Taylor and van Dyke, 1985;Song and Parenti, 1995). In stained individuals, total body length (TL, from the top of the snout to the posterior edge of fin fold), length and height of the head, and horizontal diameter of the eye were measured. ...
Migration of Sakhalin sculpin Cottus amblystomopsis larvae from the river to the sea for early rearing the primary dispersion, occurs in the form of passive downstream migration in the first 1.0-1.5 h after dark. Reaction of larvae to decrease of illumination ensures their involvement into the flow and the implementation of downstream migration. Total duration of primary dispersion period does not exceed 3 days. Body length of the larvae is on average 7.7 mm, their vertebrae and spinous processes are formed, the anlages of unpaired fins are noticeable, and pectoral fins are well developed.
... We referred to Sabaj (2020) for additional information about these scientific collections. When examining specimens from more comprehensive collections, a few skulls were prepared dry or cleared and stained, following a modified procedure originally outlined by Taylor and Van Dyke (1985). Additionally, certain skulls were partially disarticulated to facilitate examination of individual bones. ...
The Mabuyinae subfamily exhibits remarkable diversity, encompassing 26 genera and 236 currently recognized species. Traditionally, the entire range of the group was attributed to the single genus Mabuya, which had a wide distribution along tropical regions of the Planet. In recent studies, phylogenetic hypotheses based on molecular data have identified four major groups, which have been further divided into geographically distinct clades. At least two phylogenetically distinct lineages of Mabuyinae are distributed in the Neotropical Region: Trachylepis atlantica and the remaining 16 genera within the Mabuyinae clade from the mainland and the Caribbean islands. Our understanding of Mabuyinae osteology is still quite limited, particularly concerning interspecific variation. This lack of information hinders our ability to make strong contributions to the phylogenetic relationships within this group or even to confirm the existence of certain new taxa considering their relatively conserved external morphology. This work provides a comprehensive anatomical reference for the adult skull of Neotropical Mabuyinae lizards, highlighting osteological features that might be useful for delimiting each genus. This descriptive guide includes illustrations and employs multiple techniques, such as dry preparation, clearing and staining, and high-resolution computerized microtomography. Our results provide additional diagnostic characteristics that include specific cranial bone arrangements, dental patterns, and cranial adaptations, such as dorsoventral head flattening, and their functional implications for bite force and cranial biomechanics. This study reinforces the importance of cranial morphology in understanding the phylogenetic relationships and evolutionary trajectories of New World Mabuyinae lizards, advocating for broader morphological sampling to enrich our understanding of these diverse reptiles.
... To visualize bones and cartilage, the specimens were cleared and stained (c&s) according to the methods proposed by Taylor and Van Dyke (1985; Figure 2). The bone complexes were dissected according to Weitzman (1962), with some adaptations. ...
Evolutionary body size decrease has profound consequences for the morphology of an organism. In the evolution of the Characidae, the most species‐rich family of Neotropical fishes, a prominent trend is the reduction of body size. The most typical effect is the simplification and reduction of morphological features through terminal deletion processes, resulting in the loss of skeletal elements and structures. To provide further information on the matter, we present a detailed description of the skeleton of Hyphessobrycon piabinhas , a poorly known, small representative of the largest genus of Characidae. We further discuss the identity and phylogenetic relationships of H. piabinhas . It belongs to the subfamily Stethaprioninae and exhibits considerable morphological similarity to other congeners from neighboring drainage systems. We identify several morphological simplifications in H. piabinhas and discuss them based on ontogenetic data available for Characiformes. These developmentally truncated elements are also present in many other small representatives of the family and seem to be among the first morphological modifications to occur in the context of body size reduction of Characidae. We argue that structural losses are not strictly correlated with sizes below 26 mm SL, although the most notable simplifications are typically observed in the miniatures.
... Meristic data are given in the description; an asterisk indicates counts of the holotype, and the frequency of each count is given in parentheses. Counts of vertebrae, ectopterygoid teeth, branchiostegal rays, procurrent caudal-fin rays, epurals, and other osteological observations were made only in cleared and stained (c&s) paratypes, prepared according to the method of Taylor and Van Dyke (1985). For analyses of the swimbladder, some specimens had their abdominal cavity exposed through a lateral section on the right side, and the swimbladder was removed. ...
A new species of Characidium shared by adjacent tributaries of the upper portions of the Tapajós and Xingu river basins is described. Characidium varii, new species, can be distinguished from the congeners by having distinctly speckled pattern of colouration, including dark blotches on cheek and ventral surface of head, by having conspicuous dark marks on fins, along with a single row of dentary teeth, isthmus completely covered by scales, 14 circumpeduncular scales, and swimbladder reduced. Molecular data reinforce the validation of the new species. The distribution of C. varii supports the hypothesis of the existence of a faunistic mixing between Tapajós and Xingu river basins, corresponding to the region of the Serra do Cachimbo and surrounding areas, previously proposed in the literature.
... Counts could not be carried out on some individuals due to conservation limitations (loss of scales) or small individuals (less than 27 mm L S ) with visually indistinguishable scales. For osteological analysis, two specimens were cleared and stained (c&s) according to the protocol of Taylor and Van Dyke (1985). The nomenclature of the osteological structures follows Weitzman (1962). ...
A new species of Characidium is described from the headwaters of the Rio Itararé, upper Rio Paraná basin, at the boundaries of the Ponta Grossa Arch and the Devonian Escarpment Environmental Protection Area. The new species is supported by both morphological and molecular data, including species delimitation methods (Assemble Species by Automatic Partitioning, Barcode Index Number, Poisson Tree Process and its Bayesian implementation, and Generalized Mixed Yule Coalescent). The species is genetically close to other species that also exhibit the presence of scales on the isthmus, including Characidium litorale, Characidium satoi, Characidium xanthopterum, and Characidium aff. zebra. The high genetic diversity among Characidium species underscores the necessity of employing a complementary perspective in studies of this group. The discovery of a new species in the headwaters of the Rio Itararé further reinforces the importance of this biogeographic region for the conservation of ichthyofauna.
... Part of the specimens we evaluated directly, were either clear and double Stained (C&S) for bone and cartilage using the methodology describe by Taylor and Van Dyke (1985) and Wassersug (1976), differentially stain cartilage blue (with Alcian blue) and bone red (with Alizarin red), while making the soft tissues translucent. Other specimens were scanned by using the μCT scanner SkyScan 1275 (Bruker micro-CT, Kontich, Belgium). ...
... In text and tables, SD is used for standard deviation. Counts of vertebrae, supraneurals, teeth, gill-rakers, procurrent caudal-fin rays, and information about osteological characters were obtained from specimens cleared and double stained for cartilage and bone following the protocol of Taylor and Van Dyke (1985). Total number of vertebrae includes the four vertebrae of the Weberian apparatus counted as separate elements and all post Weberian vertebrae including the compound ural centrum, which was counted as a single vertebra. ...
The miniature fish genus Priocharax currently comprises seven valid species: P. ariel, P. britzi, P. marupiara, P. nanus, P. pygmaeus, P. toledopizae and P. varii. Except for P. ariel and P. pygmaeus, all the species are endemic to Brazil. Priocharax is characterized by several paedomorphic features such as reductions in the laterosensory system, number of fin rays, and ossification of parts of the skull. The most striking reductive character of Priocharax is the larval rayless pectoral fin in which most of its ossified endoskeletal elements are absent. We describe herein two new species of Priocharax from the vicinity of Santarém municipality, Pará state, Brazil. Both new species are distinguished from each other and from congeners by a combination of morphological features (i.e., osteological, morphometric, and meristic data) and molecular information (i.e., DNA barcode). We also present an updated maximum likelihood tree which now includes all nine species of Priocharax.
... Fixation and preservation of specimens as described in Costa et al. (2023b). Osteological preparations followed Taylor and Van Dyke (1985). Specimens were deposited in Instituto de Biologia, Universidade Federal do Rio de Janeiro (UFRJ) and Centro de Ciências Agrárias e Ambientais, Universidade Federal do Maranhão (CICCAA). ...
Mountainous regions typically host a great diversity of small-ranged species, often contributing for delineating world biodiversity hotspots. Species of trichomycterine catfishes have been recorded for several high-altitude areas of tropical South America, but field inventories in top mountains of southern Brazil are still rare. Here we report four new small-ranged species collected in streams of the Rio Iguaçu at Serra do Espigão (RISE) in altitudes between about 970 and 1020 m asl, one in the eastern portion of RISE and three in the western portion. A molecular phylogenetic analysis indicated that these species belong to the Cambeva beta-clade, which comprises all species endemic to the Rio Iguaçu drainage, but together not forming a monophyletic group. The analysis also indicated that species endemic to high altitudes are variably related to species from lower altitudes. The only eastern RISE species appears in a basal position of a well-supported clade (Cambeva beta1-clade), with the western RISE species appearing in a subclade of the Cambeva beta1-clade with species occurring in a vast area of southern Brazil. New species are diagnosed by combinations of morphological character states, including meristic, colouration, latero-sensory system, and osteological data.
... Scale count in the mid-longitudinal series includes all scales between the upper attachment of the opercular membrane and the base of the caudal fin, excluding small scales posterior to the hypural plate. Numbers of vertebrae were recorded only from cleared and stained (C&S) specimens, prepared according to Taylor and Van Dyke (1985). Frontal squamation nomenclature follows that described by Hoedeman (1958), and that of cephalic neuromast series follows Costa (2001). ...
A new species of Melanorivulus is described from the upper Taquari River drainage, upper Paraguay River basin, in the Western Brazilian Cerrado. This species is a member of the Melanorivulus pictus group, endemic to the central Brazilian plateau and adjacent areas. Melanorivulus terena, new species, is endemic to the Paraguay River basin and is possibly closely related to other species endemic to the upper Paraná River basin, such as M. linearis, M. interruptus and M. egens, by the absence of distinctive dark marks on the humeral region in males. The new species is distinguished from all other species of the M. pictus group by a distal margin of unpaired fins and pelvic fin that is orangish red, and by the number of scales in the transversal series. The possible close relationship between the new species and other species recorded in the Paraná River basin may indicate an ancestral interconnection of the headwaters of the Rio Taquari (Paraguay River basin) with the headwaters of the upper Rio Verde and Rio Pardo (Paraná River basin). http://www.zoobank.org/urn:lsid:zoobank.org:pub:8B0027D9-8346-4ADB-AE9E-8C770823B8D9 ARTICLE HISTORY
... Methods for preparing specimens, taking morphological data, and morphological terminology followed methods of our most recent studies on systematics of eastern South American trichomycterines (e.g. Costa et al. 2023a), which were based on Taylor and Van Dyke (1985) for clearing and staining techniques for osteological analysis, Costa (1992) and Costa et al. (2020) for taking morphometric and meristic data, Costa (2021) and Kubicek (2022) for bone terminology, Arratia and Huaquin (1995) and Bockmann and Sazima (2004) for terminology of pores of the cephalic latero-sensory system, and Bockmann and Sazima (2004) and Costa et al. (2020) for fin-ray formulae. In lists of specimens, the abbreviation C&S indicates cleared and stained specimens for osteological analyses. ...
The mountain ranges of southeastern and southern Brazil are inhabited by a great diversity of catfishes of the genus Cambeva. The Cambeva variegata group, diagnosed by having a prominent skin crest similar to an adipose fin, an interrupted supraorbital laterosensory canal, with an additional supraorbital S4 pore, and a relatively small premaxilla with an accentuated constriction on its lateral portion, occurs in a broad area of south-eastern Brazil, mostly within the savannah-like Cerrado vegetation at the northern-most part of the genus distribution. The new species described here was collected in streams of the Rio das Velhas drainage, Rio São Francisco basin, draining the Serra do Espinhaço. The new species is diagnosed by having more interopercular odontodes and a combination of morphometric data, colour pattern, relative dorsal-fin origin and vertebra position, and-fin-ray morphology. Field studies indicate that the two localities where the new species occur are being dramatically affected by negative human impacts, putting it in severe risk of extinction.
... Based on the data gathered, we also explore their phylogenetic significance. were cleared and double stained (see Appendix 1) according to the Taylor and Van Dyke (1985) protocol. Due to material availability, a single individual of G. chrysosticta, G. elicioi, and G. monticola were studied. ...
Hemiphractids have a singular mode of reproduction that involves maternal care. The Andean‐endemic Gastrotheca marsupiata species group includes direct‐developing and tadpole‐bearing species, the latter trait being unique among Gastrotheca . Larval morphology has proven to be a valuable source of evidence to understand the taxonomy and evolution of frogs but remains understudied in Hemiphractids. Herein, we redescribe the larval cranium of G. espeletia , G. gracilis , G. marsupiata , G. peruana , G. pseustes , and G. riobambae , and describe those of G. aureomaculata , G. chrysosticta , G. litonedis , G. monticola and G. psychrophila . Additionally, based on the data gathered, we explore their phylogenetic significance, expanding the knowledge regarding Gastrotheca larval internal morphology. We suggest that the presence of the posterolateral process of crista parotica, the concave palatoquadrate, the quadratoorbital commissure, and the proximal commissures II and III are putative synapomorphies for Gastrotheca . Furthermore, we suggest the long pseudopterygoid process as a putative synapomorphy for Hemiphractyidae.
... Measurements are expressed as percentages of standard length (SL), except subunits of the head, which are recorded as percentages of head length (HL). In the description, counts of vertebrae and pleural ribs were taken from two cleared and stained (c&s) paratypes, prepared according to Taylor & Van Dyke (1985). Terminology from frontal squamation follows Hoedeman (1958) and Costa (2006). ...
A new species of Melanorivulus, belonging to the Melanorivulus zygonectes species group, is described from the rio Galera, a tributary of the right bank of the upper rio Guaporé, Amazon basin, Mato Grosso state, Brazil. It is diagnosed from congeners by the following combination of characters: absence of pelvic fins; presence of a black band along the entire caudal-fin margin in males, typically more conspicuous on dorsal and ventral portions; presence of a wide oblique bars anteriorly and wide chevron-like marks posteriorly to middle of flank. This is the first record of the genus Melanorivulus for the rio Madeira basin.
... For the evaluation of the skeletal system of M. macrocephalus the technique of diaphanization was applied, according to Taylor and Van Dyke (1985). Animals from treated and control groups that had visible morphological effects (radiological imaging) were eviscerated, fixed in buffered formalin (10%) and dehydrated in a growing series of alcohols. ...
Objective: Megaleporinus macrocephalus, a native species from the Neotropical region, was used as a model to evaluate the effects of pyriproxyfen on larval development at a dose that could be found in the environment. Theoretical Framework: Pyriproxyfen is a compound used to control of the mosquito Aedes aegypti, vector of Neotropical diseases. In insects, pyriproxyfen acts as a juvenile hormone analogue, inhibiting embryogenesis and the development of characteristics of adults through the inhibition of ecdysone. Pyriproxyfen has demonstrated effects on the survival rate, behavior, and morphology during development of non-target organisms. Method: In this study Megaleporinus macrocephalus was exposed to a dose of 2.5μg/L of pyriproxyfen on the 8th day after hatching and the presence of bone malformations was evaluated. For the evaluation was applied technique of diaphanization and radiological imaging. Results and Discussion: Out of the total of the individuals, 43% had some type of bone malformation: 24% had scoliosis and kyphosis of the vertebral column, 9% had reduction of pectoral fins, 5% had malformation in the anal fin and 5% absented at least one of the pelvic fins. These data reinforce the action of pyriproxyfen as a teratogen, acting on larval development in reduced doses, which can be found in the environment. Our study warns that these molecules might interact in the mechanism of gene expression mediated by retinoic acid, important morphogen during embryogenesis and organogenesis. Research Implications: The practical and theoretical implications of this research are discussed, providing insights into how the results can be applied or influence practices in the field of teratology. These implications could encompass control of the vectors, conservation biology and the prevention of embryonic and fetal anomalies. Originality/Value: This study not only does it reinforce the urgency to study how these molecules interact but also suggests caution when using the compound as a controller for vectors until the true security is acknowledged.
... Measurements based on photographs of fixed specimens were taken using the software ImageJ (Abràmoff et al., 2004). Specimens for osteological examination were either cleared and double-stained following Taylor and Van Dyke (1985) or µCT-scanned at varying resolutions (1.9-7.3 μm) using either a GE v|tome|x s240 dual tube 240/180 kV system (General Electric, Fairfield, CT) or a Bruker Skyscan 1173 high-energy micro-CT (Bruker Inc, Billerica, MA). CT data were edited, segmented, and colorized using VGStudio Max (v3.3-v2023.3; ...
The taxonomy of the blood-feeding candiru catfish genus Paravandellia is poorly resolved, incomplete, and hindered by a complex nomenclatural history, with many species being arbitrarily synonymized, considerable morphological and geographic variation being unevaluated, and morphological boundaries between the genus and its sister, Paracanthopoma, differing among authors. Herein, we describe three new species of Paravandellia based on photomicros-copy, cleared and stained specimens, and µCT imagery. We also reevaluate diagnostic character states for Paravandellia and Paracanthopoma, propose a new character to diagnose Paravan-dellia, and present our discovery of a possible type specimen of Parabranchioica teaguei and additional non-type specimens of Branchioica bertoni, junior synonyms of Parav. oxyptera. Based on these observations, we confirm Parav. alleynei and a recent newly described species of Paracanthopoma as members of a rediagnosed, putatively monophyletic Paravandellia, increasing its richness from two to seven species. We also discuss interrelationships of Para-vandellia species based on the characters described.
... Nomenclature of anatomical structures follows that used by the three mentioned authors and Dahdul et al. (2010), included in the Teleost Anatomy Ontology of Uberon Ontology Documentation (Mungall et al. 2012, http://obophenotype.github.io/uberon/). Specimens were cleared and stained (C&S) following Taylor and Van Dyke (1985). An asterisk (*) indicates holotype counts. ...
The banjo catfish, Xyliphius barbatus, belongs to the Aspredinidae family and typically inhabits the main channels of medium to large rivers in the La Plata River basin. The mimetic coloration with the substrate and the benthic lifestyle likely contribute to the challenge of sampling this species, resulting in its underrepresentation in museums and ichthyological collections. In fact, the original description of X. barbatus was based solely on two specimens. Consequently, little is known about its osteology, distribution, and phylogenetic relations. In this work, these information gaps are filled and the distributional range for X. barbatus is extended to northwestern Argentina.
A crowdfunding initiative carried out by aquarists allowed us to sample tributaries of the rio Tapajós basin in the surroundings of Jacareacanga and Maués towns, Pará and Amazonas states, respectively, in the Brazilian Amazon. During this expedition, 13 Corydoradinae species were captured, from which at least five could be confirmed as new to science. In this article, we formally describe two of these species. Both new species can be distinguished from their congeners by having the following features: (I) ventral surface of trunk with small to relatively large coalescent platelets, forming a typical mosaic-like pattern, which entirely or almost entirely covers the ventral surface trunk; (II) small, whitish yellow or beige blotches at least on predorsal portion of body; and (III) a large, smoothly arched dark brown or black patch extending from anterior portion of parieto-supraoccipital towards region of interopercle, transversally crossing orbit and forming typical mask-like blotch. The new species differ, one from another, by the conspicuously different patterns of dark markings on flanks. Considering their peculiar head morphology, a broad discussion on the relation of the mesethmoid anatomy and snout shape within Corydoradinae is provided. Additionally, a discussion of the possible positive adaptive value of their color patterns is provided.
Leporinus bleheri was described for the Guaporé-Iténez basin, in the border between Bolivia and Brazil. More recently, specimens of a similar-looking banded Leporinus were sampled in distinct rivers in the Madeira basin. Herein, we use an integrative approach combining molecular and morphological data to investigate the taxonomic status of the new samples. Morphometric data were used to perform a Principal Components Analysis (PCA). Both species specimens were cleared and double-stained for osteological description. DNA barcodes were used to investigate the genetic distance between samples and for species delimitation analyses. Molecular markers COI, CytB, 16S, Myh6, RAG1, and RAG2 were applied to estimate the phylogenetic relationships of the two species. Our results show morphological and genetic differences between samples of L. bleheri and the new species. Both species are herein (re)described and illustrated. The new species is distinguished from L. bleheri by having 12 scale rows around the caudal peduncle (vs. 16). The genetic distance between the new species and L. bleheri was of 3.93%, and species delimitation analysis recovered the samples as separated molecular units. The multi-loci analysis corroborated the sister-group relationships between both species, including them within the Leporinus fasciatus group, which was recovered as non monophyletic.
Two new species of Neoplecostomus are described from the headwaters of the rio Sapucaí drainage, affluent of the rio Grande in upper rio Paraná basin. The new species are most similar to each other, and can be diagnosed from congeners by having the exposed area of the first plates of mid-ventral and ventral series narrower than the naked area surrounding each plate; different tooth morphologies and numbers in males and females; arrangement of odontodes on caudal-peduncle plates; size of adipose fin and cranial osteological character states. Both new species are endemic to Serra da Mantiqueira, southeastern Brazil. Some comments are made on their intraspecific variation, genetics, and conservation.
ABSTRACT:
Trichomycterus caribensis sp. nov., is a medium-sized catfish in this gender of the Sevilla River in the Sierra Nevada of Santa Marta, Magdalena Department in Colombia. T. caribensis, differs from other species by having two phenotypic colorations specific to the species. The specimens of 70.7 - 79.2 mm of E.L. have a thin black line on the horizontal line, running from the operculum to the center of the base of the caudal fin, ending with a small black dot, with irregular large and small dots on the upper, lower, and dorsal region of the body. The dorsal region of the
head has small black dots on the flanks and center up to the snout in black color. The dorsal,pectoral, anal, and caudal fins have dots at the base, with black-colored rays. The pelvic fin is hyaline. The horizontal line is black and more noticeable in specimens of 83.4 - 93 mm of S.L.The black dots on the lower region are numerous and small. Small black dots are more numerous in the upper region of the horizontal line; the large black dots are found more towards the supradorsal region, from the supraoccipital to the beginning of the caudal fin. The caudal, dorsal,and pectoral fins have small dots throughout the area. The pelvic fin is hyaline. The abdominal
and lower regions of the head are light brown. It has 36 free vertebrae and 5 branchiostegal rays.
The genus Pseudacanthicus encompasses eight recognized species so far: P. histrix, P. serratus, P. spinosus, P. fordii, P. leopardus, P. pitanga, P. pirarara, P. major. Only P. pirarara has been formally described from the rio Xingu basin. To address this gap in taxonomic knowledge of the region, a new species of the Pseudacanthicus is described here, aimed at enhancing our understanding of the genus within the rio Xingu basin and contributing to conservation efforts. The new species is primarily found downstream the impact zone of the Belo Monte Hydroelectric Power Plant. It can be promptly diagnosed from congeners by the color pattern of the body dark brown to black with light gray vermicular spots on the dorsal and ventral surfaces, and fins; lower maximum number of teeth in premaxilla and dentary; and other osteological characters. It’s worth noting that the ichthyofauna of the Amazonian drainages lacks comprehensive taxonomic and biological information regarding Pseudacanthicus. In this context, unchecked anthropogenic activities are leading to changes in the ecosystem, often resulting in the extinction of species even before they are scientifically addressed.
Arthroleptidae are an ecologically diverse group of sub-Saharan frogs. Arthroleptid tadpoles predominately occur in slow flowing to torrent waters. Their musculoskeletal system and the relationship between tadpole morphology and lifestyle are poorly understood. Here, we investigated the cranial morphology of four arthroleptid tadpoles occurring in different microhabitats: Leptopelis parkeri, Astylosternus occidentalis, Trichobatrachus robustus, and Nyctibates corrugatus. The crania of the tadpoles of A. occidentalis, N. corrugatus, and T. robustus are highly modified relative to L. parkeri, with wide and partly or completely fused cornua trabeculae, a fused cartilago labialis superior, as well as several modifications of the palatoquadrate, such as a broad commissura quadratocranialis and a processus ventralis which expands the surface for the origin of the large m. orbitohyoideus. The processus hyoquadratis is an evolutionary novelty, forming a functional unit together with the ceratohyale in the cranium of N. corrugatus. Finally, we compared the cranial morphology of these arthroleptids to other lotic and non-lotic species. Although the processus ventralis is not a generalized feature of the cranium in lotic species, it is not present in lentic species.
Hypostomus khimaera, described from the upper rio Paraguai basin in Brazil, was reported to present some morphological variations in its original description, which allied to its relatively wide geographical distribution reinforced the need for a new assessment of its taxonomic status. Here, we analyzed a new robust set of material, composed by 636 specimens from several localities within the upper rio Paraguai basin, besides the material listed in the original description. From this, it was possible to better understand the limits of the species providing a more accurate diagnosis and a redescription for H. khimaera, which also brought some light to the limits of the H. cochliodon group itself. The species can be distinguished from its congeners by having the following features: (I) absence of a notch between the metapterygoid and hyomandibula, (II) acutely angled dentaries, with up to about 90°, (III) teeth with medial cusp ranging from villiform to shovel-shaped, (IV) opercle completely surrounded by a thick layer of skin, (V) a longitudinal dark stripe along middle portion of flanks, which is variably diffuse, and (VI) dark spots on at least one part of the body. Although morphological and color pattern differences have been found in different populations along the upper rio Paraguai basin, all examined specimens are herein considered to belong to H. khimaera, a decision based on both morphologic and molecular analyses. Additionally, an updated identification key for the Hypostomus species in the Brazilian portion of the upper rio Paraguai basin is also provided.
During early development, fishes undergo significant changes that influence external morphology and the functioning of internal
rgans and systems. This often results in gradual variation of the morphological traits of individuals across developmental stages. The investigation of larval and juvenile fish development and growth patterns has pertinent implications for the systematic and ecological elucidation of species. Bryconops gracilis is a medium-sized fish, omnivorous that inhabits lotic and lentic environments with acidic and transparent waters in the Amazon basin. In this study, the early development of B. gracilis is described, until recently a practically unknown species. In terms of development, we used morphological, meristic, and morphometric data to char-
acterize the larvae and juveniles. The individuals were collected in the Curu ́a-Una River, Amazon basin, Brazil. Fifty-four specimens were examined. Samples include individuals with 3.39–21.79 mm SL. Yolk-sac larvae have two attachment organs on the dorsal surface of head and body. The larvae of B. gracilis are considered altricial, with a fusiform body, and the intestine reaches the median region of the body. Initially, the mouth is subterminal
and becomes isognathic from the postflexion stage on. During the postflexion stage, the most relevant morphological changes occur (e.g., presence of all fins, mouth position similar to adults, increased body pigmentation), making individuals more specialized to explore new habitats and diets and maximize their
chances of survival. Furthermore, vertebrae and myomeres are compared and assist with differentiating some Bryconops species at early life stages that occur in sympatry in the Amazon basin. Our results contribute to knowledge about the external morphology of neotropical freshwater fishes, enabling the identification of larvae and juveniles through traditional taxonomy and broadening the perspective on the ontogenetic study of the
adipose fin in Characoidei.
Garra dohjei, a new labeonine fish with transverse lobe and incipient proboscis is described from the Ñiangdai, a tributary of the Brahmaputra River, Meghalaya, India. The new species is distinguished from its congeners with transverse lobe and incipient proboscis, in having a well-developed transverse lobe with around 9–12 minute tubercles, deep transverse groove between transverse lobe and incipient proboscis, black spot immediately anterior to upper angle of gill opening, 5–6 dark black stripes on caudal peduncle, 33–35 lateral line scales, 9–10 predorsal scales, 16–circumpeduncular scales, 15 branched pectoral-fin rays, and total vertebrae 33.
A new species of Cambeva occurring in the rio Piquiri and Ivaí, upper rio Paraná basin, Brazil, is described using the combination of morphological and molecular data. The new species is distinguished from most congeners by the presence of a notch in the posterior portion of the metapterygoid, number of branchiostegal rays, opercular and interopercular odontodes, and ribs. In addition, the results corroborated the existence of a single species with wide intraspecific variation in body coloration. The type-locality is within the area of influence of the Perobas Biological Reserve, a Conservation Unit in the Paraná State, composed of two Atlantic Forest physiognomic forms. Considering that the upper rio Paraná basin is an area of significant anthropic influence, it is crucial to describe and preserve species to understand their ichthyofauna.
The morphology, phylogenetic position, and distribution of a recently revalidated species of leuciscid minnow, Phoxinus isetensis, were substantially clarified. The species was described in the late 18th century from the Middle Urals but later synonymized with Phoxinus phoxinus. As believed, P. isetensis is distributed in the Arctic Ocean catchment from the Murman coast via West and East Siberia until the Pacific Ocean catchment in Far East and Northeastern Asia. Our study, with the use of mtDNA markers coupled with extensive morphological data, showed that the distribution of P. isetensis is greatly different. Currently, this is the most widespread Phoxinus species in Europe, distributed in Northern and Eastern Europe and on the western edge of Siberia (Iset and Ural basins). In particular, P. isetensis inhabits the basins of the Caspian, Baltic, White, Barents, and Kara seas, possibly occurring in the North Sea basin. The species was redescribed, and the type locality and neotype were designated. The main morphological difference from other Phoxinus spp. is the large total number of vertebrae (39–43, mode 41) due to an increase in the number of caudal vertebrae (16–21, mode 19). Phylogenetically, P. isetensis is a sister to the Caucasian species P. colchicus (p-distance = 5%). The wide distribution of P. isetensis within the area of the Last Glacial Maximum suggests rapid colonization of deglaciated regions, probably due to its adaptation to a cold climate.
The genomes of living lungfishes can inform on the molecular-developmental basis of the Devonian sarcopterygian fish–tetrapod transition. We de novo sequenced the genomes of the African (Protopterus annectens) and South American lungfishes (Lepidosiren paradoxa). The Lepidosiren genome (about 91 Gb, roughly 30 times the human genome) is the largest animal genome sequenced so far and more than twice the size of the Australian (Neoceratodus forsteri)¹ and African² lungfishes owing to enlarged intergenic regions and introns with high repeat content (about 90%). All lungfish genomes continue to expand as some transposable elements (TEs) are still active today. In particular, Lepidosiren’s genome grew extremely fast during the past 100 million years (Myr), adding the equivalent of one human genome every 10 Myr. This massive genome expansion seems to be related to a reduction of PIWI-interacting RNAs and C2H2 zinc-finger and Krüppel-associated box (KRAB)-domain protein genes that suppress TE expansions. Although TE abundance facilitates chromosomal rearrangements, lungfish chromosomes still conservatively reflect the ur-tetrapod karyotype. Neoceratodus’ limb-like fins still resemble those of their extinct relatives and remained phenotypically static for about 100 Myr. We show that the secondary loss of limb-like appendages in the Lepidosiren–Protopterus ancestor was probably due to loss of sonic hedgehog limb-specific enhancers.
Se describen cinco nuevas especies de Trichomycterus de cueva para el Departamento de Santander, se distinguen de los otros Trichomycterus de cueva conocidos por su coloración fenotípica ontogénica, que en los adultos de Trichomycterus galvisi sp. nov., es de un color amarillo claro en todo el cuerpo, 3 hileras horizontales delgadas en los flancos corporales que van desde el final de la cabeza, hasta la base de la aleta caudal. Un ejemplar de 60,1 mm de L. E., es totalmente anoftalmo, como es de esperarse en un pez troglóbido. Tiene 34 - 35 vértebras libres. T. macareguaensis, la coloración general del cuerpo es de color amarillo claro, con una línea delgada en los ejemplares de 55,9 - 70 mm de L.E. Tiene 33(2) vértebras libres. T. choroloensis, con una mancha parda oscura a los lados mentonianos de la cabeza y en la base de la aleta dorsal. La base de las aletas con una carnosidad en la base y las regiones distales son hialinas. Tiene 35(2) vértebras libres. T. santuarioensis el color general del cuerpo es amarillo oscuro, con una línea horizontal ancha y otra línea delgada encima y debajo de la línea horizontal; estas se observan en todos los tamaño. Tiene 34(2) - 35 vértebras libres. T. simacotaensis, todo el cuerpo es albino con ojos rojos. Una mancha redonda más clara en la región dorsal de la cabeza. Es de tamaño pequeño 42,8 mm de L.E., tienen 33 vértebras libres. Estos ecosistemas espeleológicos, tienen una biodiversidad única, formada por un proceso evolutivo de millones de años, que han producido un endemismo íctico propio de cada cueva o caverna.
Se describen dos nuevas especies de peces Trichomycterus para el Departamento de Santander - Colombia. Se distinguen de las otras especies conocidas por su coloración fenotípica onto-filogenética, que en los adultos de Trichomycterus sanchezi sp. nov. es de un fondo pardo oscuro, con algunos puntos grandes irregulares oscuros en la parte posterior del cuerpo, una línea ancha clara en la región dorsal del cuerpo. Los bordes de la cabeza son de un color pardo claro. El inicio de la aleta dorsal, región distal de la caudal - toca las narinas. El inicio de la aleta dorsal, base aleta caudal - toca el opérculo. El primer radio de la aleta pectoral 10,4 mm es menor que la longitud de la cabeza (9,4 - 13,9 mm). Su longitud estandar máxima es mediana; 75,2 mm de L.E. 33 - 34 vértebras libres, sin incluir el centro caudal complejo. T. curitiensis sp. nov. El patrón de coloración es de un fondo pardo oscuro en todo el cuerpo. Los ejemplares menores a 67,6 mm L.E. son más claros. Tiene una línea negra delgada en la región dorsal, que va desde el supra-occipital hasta el inicio de la aleta dorsal. Las aletas no tienen puntos, y son más claras en la parte distal. En vivo estos ejemplares tienen una banda ancha roja en la línea lateral. El inicio de la aleta dorsal, región distal de la aleta caudal - llega a la parte anterior del ojo. El inicio de la aleta dorsal, base de la aleta caudal llega a la parte anterior de la base de la aleta pectoral. El primer radio de la aleta pectoral 11,6 mm es menor que la longitud de la cabeza 11,1 - 17 mm. Su longitud estándar máxima es mediana 98,1 mm L. E. , 34 vértebras libres. Palabras claves: Bagres transandinos, Taxonomía, Morfología, pez neotropical.
We describe a new species of the genus Atlantirivulus from a small first-order stream on the right margin of the Paraná River basin in the Mato Grosso do Sul, Brazil. The region of occurrence of the new species is known to be a hotspot for Melanorivulus species. This area, however, is approximately 700 km away from the record of occurrence of its closest congeners, which are distributed along the Brazilian coast in different hydrographic basins. Atlantirivulus enigmaticus, new species, is distinguished from all congeners by it s unique coloration, which consists of the flank being purplish grey with light green iridescence with brownish red dots scattered along of the body, by the neuromasts of the infraorbital series being aligned around eye, and by the presence of the short ventral process of the posttemporal. The phylogenetic position of the new species within the Atlantirivulus genus was based on molecular phylogenetic analysis using sequences of the mitochondrial gene cyto- chrome oxidase subunit 1. The results show that the new species is closely related to Atlantirivulus luelingi from the coastal drainages of the Brazilian state Santa Catarina. The phylogenetic position of the new species among congeners endemic to coastal river basins may be related to ancestral connections between coastal drainages and the Paraná River basin. The new species constitutes the westernmost record for the genus, and the first record of Atlantirivulus in the Paraná River basin. Insufficient collection efforts in areas of potential occurrence for the group and extinction processes in the broad region between the locality of the new species and the distribution areas of the remaining species may be a possible explanation for this disjunct distribution.
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