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Caudal skeleton of Brycinus macrolepidotus, MZUSP 60303, 58.6 mm SL; lateral view, anterior to left.
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The overall most parsimonious hypothesis of relationships based on 200 characters indicates that the Alestidae is the closest relative of Chalceus, a genus previously assigned to the Neotropical Characidae. Chalceus is shifted into the Alestidae, which becomes the only trans-Atlantic family level group within the Characiformes. Various previously p...
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Citations
... Of the four characiform families found in African fresh waters, Alestidae is the largest with over 100 valid species (Oliveira et al. 2011;Fricke et al. 2023). These are distributed throughout the lowland rivers in sub-Saharan Africa (Roberts 1975;Zanata and Vari 2005;Arroyave and Stiassny 2011). The family is considered to be monophyletic (e.g., Orti and Meyer 1997;Murray and Stewart 2002; Arroyave and Stiassny 2011); however, relationships among the constituent members remain unclear. ...
... Previous classifications of tribes and subfamilies based on dentition and body size were created prior to the prevalence of cladistics techniques, and resulted in polyphyletic groupings (Murray and Stewart 2002;Calcagnotto et al. 2005; Arroyave and Stiassny 2011). Intrafamilial relationships among alestids remain unresolved (e.g., Hubert et al. 2005;Zanata and Vari 2005). One aspect of alestid diversity that may contribute to the difficulty in establishing a natural classification is the great disparity in body size within the family. ...
... Previously, a number of alestid species of small size were grouped together in a single taxon, 'Petersiini' (e.g., Poll 1967;Géry 1995). However, more recently these size differences have been hypothesized to result from multiple independent miniaturization events within family (e.g., Hubert et al. 2005;Zanata and Vari 2005). If this latter hypothesis is correct, then the features previously used to unite small alestids are likely related to small size (i.e., the byproduct of truncated ontogeny) and do not represent homology indicative of phylogenetic relationship. ...
Members of Alestidae, a family of characiforms found in sub–Saharan Africa, have a wide range of adult body sizes. Because of this range of adult size, phylogenetic characters for the group may be difficult to distinguish from ontogenetic features, resulting in groups being united based on body size rather than evolutionary
relatedness. Although previous studies have presented the morphology and osteology of some small and miniature taxa, these were pre-cladistic and did not attempt to distinguish between phylogenetic and ontogenetic features. Here we provide a study on the external morphology and osteology of a small alestid,
Hemigrammopetersius barnardi which has reductions and losses of osteological features. We compared this species to juveniles of Alestes dentex, an alestid that attains much larger adult size, to identify characters in H. barnardi that potentially result from a decrease in body size rather than shared ancestry. We found that
the loss of particular bones of the circumorbital series and postcranium, as well as a reduction of the sensory canal system, are likely the result of small body size, and therefore are not useful in establishing phylogenetic relationships among alestids.
... In the most recent revisional study of the genus, Paugy (1986) divided Brycinus into three informally named species groups: the macrolepidotus group, the longipinnis group, and the nurse group. Subsequent morphological (Murray and Stewart, 2002;Zanata and Vari, 2005) and molecular (Calcagnotto et al., 2005;Hubert et al., 2005;Arroyave and Stiassny, 2011) studies, while differing markedly in taxon coverage and details of resolved relationships, consistently refuted the monophyly of Brycinus. In agreement with both morphological and molecular studies, Zanata and Vari (2005) reassigned Paugy's longipinnis group to the genus Bryconalestes (type species Bryconalestes longipinnis), and now including B. bartoni, B. derhami, B. intermedius, B. tessmanni, and B. tholloni, thereby restricting membership of Brycinus to the macrolepidotus and nurse groups. ...
... Subsequent morphological (Murray and Stewart, 2002;Zanata and Vari, 2005) and molecular (Calcagnotto et al., 2005;Hubert et al., 2005;Arroyave and Stiassny, 2011) studies, while differing markedly in taxon coverage and details of resolved relationships, consistently refuted the monophyly of Brycinus. In agreement with both morphological and molecular studies, Zanata and Vari (2005) reassigned Paugy's longipinnis group to the genus Bryconalestes (type species Bryconalestes longipinnis), and now including B. bartoni, B. derhami, B. intermedius, B. tessmanni, and B. tholloni, thereby restricting membership of Brycinus to the macrolepidotus and nurse groups. The monophyly of Brycinus as so restricted, was supported by Zanata and Vari (2005) based on four non-exclusive morphological synapomorphies: four teeth in the outer row of each premaxilla (reversed to five or six in some members of the macrolepidotus group, or reduced to three in some members of the nurse group); circuli oriented posteriorly over the scales and relatively straight or slightly inclined towards the horizontal midline of each scale (widespread among alestids); deep-lying midlateral stripe extending from midbody to the caudal peduncle (a heterogeneous feature, reversed in numerous species); development of a median anal-fin lobe in males formed by the relative elongation of the fifth to eighth anal-fin rays (reversed in macrolepidotus group, and present in numerous alestid genera). ...
... In agreement with both morphological and molecular studies, Zanata and Vari (2005) reassigned Paugy's longipinnis group to the genus Bryconalestes (type species Bryconalestes longipinnis), and now including B. bartoni, B. derhami, B. intermedius, B. tessmanni, and B. tholloni, thereby restricting membership of Brycinus to the macrolepidotus and nurse groups. The monophyly of Brycinus as so restricted, was supported by Zanata and Vari (2005) based on four non-exclusive morphological synapomorphies: four teeth in the outer row of each premaxilla (reversed to five or six in some members of the macrolepidotus group, or reduced to three in some members of the nurse group); circuli oriented posteriorly over the scales and relatively straight or slightly inclined towards the horizontal midline of each scale (widespread among alestids); deep-lying midlateral stripe extending from midbody to the caudal peduncle (a heterogeneous feature, reversed in numerous species); development of a median anal-fin lobe in males formed by the relative elongation of the fifth to eighth anal-fin rays (reversed in macrolepidotus group, and present in numerous alestid genera). However, subsequent molecular studies (Calcagnotto et al., 2005;Arroyave and Stiassny, 2011;present study) resolve Brycinus (exclusive of Bryconalestes) into two, distantly related clades, suggesting the likely homoplastic nature of these and other characters thought to support the monophyly of Brycinus (Murray and Stewart, 2002;Hubert et al., 2005). ...
A time-calibrated phylogeny, based on nuclear ultraconserved elements and including representatives of all major alestid lineages, strongly supports two distantly related clades within the currently accepted concept of Brycinus. The first, which includes the type species of the genus, B. macrolepidotus (herein Brycinus), and a second, composed of taxa previously referred to as the B. nurse group (herein Brachyalestes), are both resolved as monophyletic. These results provide strong evidence for the restriction of the genus Brycinus to nine species, and for the revalidation of the genus Brachyalestes to accommodate 20 valid species. Within Brachyalestes, a new species from the Lulua River basin, initially misidentified as Brycinus kingsleyae, is described and resolved as sister to the widespread, central Congolese lowland species, Brachyalestes bimaculatus. Within Brachyalestes, a subclade mostly restricted to the Central Congo basin is esti- mated to have undergone diversification within the last 10 million years, suggesting that Late Neogene riverine reor- ganization likely influenced their allopatric speciation. The split of the new species, endemic to high elevation tributaries of the Lulua River, from its lowland sister species, Brachyalestes bimaculatus, suggests a Late Miocene/Early Pliocene colonization into the upland river ecosystems of the Katanga plateau in the southwestern Democratic Republic of Congo.
... Counts are followed by their frequency in parentheses, and asterisks indicate the counts of the holotype. Osteological terminology follows Weitzman (1962) with the modifications adopted by Zanata and Vari (2005); myological terminology follows Winterbottom (1973); cephalic lateralline terminology follows Pastana et al. (2020). Institutional abbreviations follow Sabaj (2020). ...
... Characidium Reinhardt, 1867 includes 84 species of South American darters, distributed from eastern Panama to Argentina (Fricke et al., 2022;Oliveira-Silva et al., 2022). Along with continuous rising of the taxonomic knowledge of the genus, the last decades witnessed novelties such as new dimorphic features (e.g., Melo, Oyakawa, 2015;Teixeira, Melo, 2021), morphological specializations, or new structures (e.g., Zanata et al., 2020;, events of miniaturization and discussions of reductive characters (e.g., Netto-Ferreira et al., 2013;Zanata et al., 2015;Graça et al., 2019), cytogenetic studies and genetic divergences used to highlight the occurrence of hidden biodiversity (Pansonato-Alves et al., 2014;Sales et al., 2018;Serrano et al., 2019), and new behavior (e.g., Flausino Junior et al., 2020). However, studies dealing with interspecific phylogenetic relationships within Characidium or testing the monophyly of the genus as it is composed nowadays are not yet available. ...
... 8a, c) described a dorsal upper process triangular or L shaped in C. tatama Agudelo-Zamora, Tavera, Murillo & Ortega-Lara, 2020 and C. dule Agudelo-Zamora, Tavera, Murillo & Ortega-Lara, 2020, respectively, but with distinct format and medially directed instead of posteriorly directed as present in C. fleurdelis (Fig. 3A). A posteriorly directed triangular projection near base of first rib was recorded by Zanata, Vari (2005) in the members of the family Alestidae (with the exception of Arnoldichthys Myers, 1926, Chalceus Cuvier, 1818and Lepidarchus Roberts, 1966) and in Astyanax Baird & Girard, 1854, Cheirodon Girard, 1855, Serrasalmus Lacepède, 1803, Piaractus Eigenmann, 1903, Tetragonopterus Cuvier, 1916, and Xenocharax Günther, 1867. The process, according to the authors, serves as the area of attachment on the rib for ligaments extending to the base of the immediately posterior rib and its parapophysis. ...
... The process, according to the authors, serves as the area of attachment on the rib for ligaments extending to the base of the immediately posterior rib and its parapophysis. The rounded process described herein in C. fleurdelis is apparently different from that described by Zanata, Vari (2005) and its function and occurence among members of Crenuchidae needs to be better evaluated in the future. ...
Abstract A new miniature species of Characidium is described from the midde rio Guaporé, rio Madeira basin, Rondônia, Brazil. The new species can be readily distinguished from all congeners by the sexual dichromatism, with females having narrow dark bars on body absent in males, and by the presence, in both sexes, of a black midventral dashed line extending from area between contralateral pectoral fins to at least the anal-fin origin. It can also be diagnosed from congeners by having strongly tricuspid teeth, with well developed and similar sized cusps in the premaxilla and outer series of dentary, and short lateral line with 6–8 perforated scales. Morphological novelties to Characidium observed in the new species include a rounded process on the first pleural rib near the vertebra, three or four haemal spines of the first caudal vertebrae distinctly elongate, neural and haemal spines of the antepenultimate vertebra not reaching origins of dorsal and ventral procurrent rays nor the origin of the caudal-fin rays.
... The presence of this unusu-al opening was first illustrated (Fig. 1) in Serrasalmus rhombeus (Linnaeus) by Rosenthal (1816), and described by Sagemehl (1885) for representatives of the South American characiform families Lebiasinidae, Characidae and Erythrinidae, and the African Alestidae, Hepsetidae, and Citharinidae, and illustrated in detail for Erythrinus, Hydrocynus and Citharinus. Presence of a QMF has since been confirmed for a large number of African, as well as New World characiforms (e.g., Weitzman 1962Weitzman , 1964Daget 1962Daget , 1963Roberts 1966Roberts , 1969Roberts , 1974Winterbottom 1980;Brewster 1986;Vari 1989Vari , 1995Zanata and Vari 2005;Mattox and Toledo-Piza 2012). ...
Citation: Britz R, Mattox GMT, Conway KW (2023) The quadrate-metapterygoid fenestra of otophysan fishes, its development and homology. Abstract We compare the ontogeny of the hyopalatine arch in representatives of the Otophysi to shed light on the homology of the so-called quadrate-metapterygoid fenestra, QMF. Described initially as a character of characiforms (tetras and allies), presence of a QMF has also been reported for cobitid loaches and a handful of cyprinids among cypriniforms, as well as for a few clupeoids. In characiforms the QMF is either already present as an opening in the palatoquadrate cartilage in the earliest developmental stages we studied, or it forms later in the cartilage by resorption of chondrocytes. Some characiforms may lack a QMF during all stages of development. In cobitids the so-called QMF develops after the bones have ossified and forms mainly by resorption of bone tissue of quadrate and metapterygoid. Previous reports of a QMF in cyprinids are erroneous and the opening in this area forms by spatial separation of the quadrate and metapterygoid from the symplectic and not by the formation of a fenestra in the palatoquadrate cartilage. We suggest referring to this type as a quadrate-metapterygoid gap, QMG. Presence of a QMF in the palatoquadrate cartilage is a putative syn-apomorphy of characiforms. Development of a QMF by bone resorption in the ossified palatoquadrate is a putative synapomorphy of Cobitidae. A QMG is variously present and developed to different degrees in opsariichthyine and danionine cyprinids. A QMF is also present in several clupeoids and deserves further study.
... The characiform family Alestidae, popularly known as African tetras, robbers, and tigerfishes, are present throughout tropical sub-Saharan Africa with notable species richness in the Congo basin and West Africa (Zanata and Vari, 2005;Stiassny et al., 2011). Morphological disparity within the family is noteworthy with species ranging in size from miniature forms such as Lepidarchus (max. ...
... Despite considerable progress toward resolving inter-and intrageneric relationships within Alestidae, much uncertainty remains (Murray and Stewart, 2002;Hubert et al., 2005;Zanata and Vari, 2005;Schaefer, 2007;Arroyave and Stiassny, 2011;Melo et al., 2022). One taxon of particular interest is the monotypic genus Petersius, the nominate genus of a large grouping of dwarf alestids designated as Petersiini (Poll, 1967). ...
... One taxon of particular interest is the monotypic genus Petersius, the nominate genus of a large grouping of dwarf alestids designated as Petersiini (Poll, 1967). Recent phylogenetic studies using anatomical and/or genetic data indicated the paraphyly of Petersiini with small-sized species variously placed across the tree of Alestidae (Murray and Stewart, 2002;Calcagnotto et al., 2005;Zanata and Vari, 2005;Arroyave and Stiassny, 2011) suggesting uncertainty for the phylogenetic placement of Petersius. ...
We review the systematics of the monotypic alestid genus Petersius and provide a taxo-nomic redescription of P. conserialis from eastern Tanzania. Morphological investigation includes direct observation and examination of radiographed and µCT-scanned data from type and non-type specimens. We delimit the taxon's geographic distribution along the lowland regions of the Rufiji and Ruvu river basins in Tanzania and provide information on ecology, sexual dimorphism, and ontogenetic variation. Petersius is herein diagnosed by the possession of a unique cuspidation patterning of the inner-row premaxillary dentition and a distinctively shaped anterodorsal margin of the supraoccipital crest. It shares with some species of Phena-cogrammus a sigmoid-shaped process on the dorsal margin of the second infraorbital, a feature lacking in other alestid taxa. Additional features of potential utility for ongoing investigation of relationships among alestid genera include the possession of contralateral premaxillae separated by the anteromedial process of the mesethmoid and without interdigitations connecting the medial surfaces of the premaxillae; four, occasionally five or six, small outer-row premaxil-lary teeth implanted alternately with those of the inner row; a dentary lacking a pair of conical inner-row teeth proximal to the symphysis; a dorsal posttemporal fossa that is smaller than the ventral fossa; a median third posttemporal fossa located entirely within the epioccipital; a trun-cate dorsomedial cranial fontanel; and a complete circumorbital series forming an uninterrupted ring around the orbit in adult specimens.
... The first fossil prior is represented by tooth fragments of Alestidae from the Ager basin (Early Eocene 54-49 Ma), Lérida, Spain (de la Peña Zarzuelo, 1996). That fossil has diagnostic similarities with premaxillary teeth of modern Alestes, Brycinus, and Bryconaethiops (Zanata and Vari, 2005). The node uniting those three genera is the most recent common ancestor (MRCA) of Alestidae in molecular reconstructions (Arroyave and Stiassny, 2011;Melo et al., 2022) where we calibrated the prior mean = 52.0; ...
Tarumania walkerae is a rare fossorial freshwater fish species from the lower Rio Negro, Central Amazonia, composing the monotypic and recently described family Tarumaniidae. The family has been proposed as the sister group of Erythrinidae by both morphological and molecular studies despite distinct arrangements of the superfamily Erythrinoidea within Characiformes. Recent phylogenomic studies and time-calibrated analyses of characoid fishes have not included specimens of Tarumania in their analyses. We obtained genomic data for T. walkerae and constructed a phylogeny based on 1795 nuclear loci with 488,434 characters of ultraconserved elements (UCEs) for 108 terminals including specimens of all 22 characiform families. The phylogeny confirms the placement of Tarumaniidae as sister to Erythrinidae but differs from the morphological hypothesis in the placement of the two latter families as sister to the clade with Hemiodontidae, Cynodontidae, Serrasalmidae, Parodontidae, Anostomidae, Prochilodontidae, Chilodontidae, and Curimatidae. The phylogeny calibrated with five characoid fossils indicates that Erythrinoidea diverged from their relatives during the Late Cretaceous circa 90 Ma (108–72 Ma), and that Tarumania diverged from the most recent common ancestor of Erythrinidae during the Paleogene circa 48 Ma (66–32 Ma). The occurrence of the erythrinoid-like †Tiupampichthys in the Late Cretaceous–Paleogene formations of the El Molino Basin of Bolivia supports our hypothesis for the emergence of the modern Erythrinidae and Tarumaniidae during the Paleogene.
... Pyrrhulina Valenciennes, 1846 and Nannostomus Günther, 1872) (Weitzman, 1964), alestids (e.g. Ladigesia Géry, 1968 andLepidarchus Roberts, 1966) (Zanata & Vari, 2005), distichodontids (e.g. some species of Neolebias Steindachner, 1894) (Vari, 1979) and several characids (e.g. ...
... Likewise, representatives of the Alestidae (i.e. Alestopetersius Hoedeman, 1951, Bryconaethiops Günther, 1873, Bryconalestes Hoedeman, 1951, Nannopetersius Hoedeman, 1956and Phenacogrammus Eigenmann, 1907Zanata & Vari, 2005) and Lebiasinidae (i.e. Pyrrhulina spp. ...
Crenuchinae is a subfamily of the fish family Crenuchidae distributed in the Amazon Basin with pronounced sexual dimorphism and exuberant colour patterns. Recent fieldwork in the tributaries of the Rio Aripuanã drainage, a large tributary of the Rio Madeira (Amazon Basin), resulted in the discovery of two distinctive, undescribed species of the crenuchin genus Poecilocharax, which are formally described herein, combining morphological and molecular data. These are the first representatives of Crenuchinae discovered after a gap of 57 years and the first records of Poecilocharax from the tributaries of the right bank of the Rio Amazonas draining the Brazilian crystalline shield. Based on a taxonomic review including all species of the subfamily, we provide an expanded morphological diagnosis for Crenuchinae. This now includes characteristics related to the lateral-line canals of head and body, the number of dorsal-fin rays and sexually dimorphic traits. In addition, we review previous characteristics used to diagnose Crenuchus and Poecilocharax, providing comments on their polarity and distribution across the subfamily. A dichotomous key is provided for the first time for species of Crenuchinae.
... Although the generic-level taxonomy of the Alestidae is generally poorly supported by apomorphy-based diagnoses (Stiassny and Schaefer, 2005;Schaefer, 2007;Arroyave and Stiassny, 2011) Phenacogrammus is currently diagnosed by the derived (reductive) feature of a truncated lateral line consisting of fewer pored than nonpored scales. While a truncated lateral line occurs in several other alestid taxa (Zanata and Vari, 2005) this feature, in combination with the presence of two small, usually conical, symphyseal teeth located immediately behind the multicuspidate outer row series on the dentary, serves to differentiate members of this genus from all others. Although taxon sampling within Phenacogrammus and across the family was incomplete, the molecular study of Arroyave and Stiassny (2011) provides support for the monophyly of Phenacogrammus as currently constituted (Fricke et al., 2021). ...
... And, as such, species discovery and description remain fundamental tasks for advancing biodiversity studies in poorly documented regions such as the central Congo basin where considerable phylogenetic diversity remains to be documented . While recognizing that future generic reassignment may be necessary, as a comparative framework for their diagnosis and description, we follow the differential generic diagnosis of Phenacogrammus provided by Poll (1967) and Zanata and Vari (2005) and assign the two new taxa from the Ndzaa River to this genus. ...
... The other two species, P. deheyni and P. polli, are currently known only from a few localities in the Cuvette Centrale, located to the north of the Mfimi-Lukenie basin (Poll, 1967;Monsembula Iyaba and Stiassny, 2013.). Based on a review of morphological features among Phenacogrammus and allied genera (Zanata and Vari, 2005;Arroyave and Stiassny, 2011) we note that the two Ndzaa species uniquely share with P. dehenyi ( fig. 3B) a derived expansion of the first pleural rib, absent in all congeners and comparative material examined. ...
Two new Phenacogrammus are described from the Ndzaa River, a small left-bank tributary of the Mfimi-Lukenie River in the central Congo basin. They share with P. deheyni, a congener endemic to the Cuvette Centrale to the north, a prominent anterior expansion of the first pleural rib; a feature interpreted here as a synapomorphy diagnostic for this species assemblage. The two new species are readily differentiated from P. deheyni based on differences in pigmentation patterning, a lower num- ber of scales in longitudinal series (26–28 vs. 29–33) and a longer head length (m. 24.9% SL vs. 21.7 and 23.2% SL). Phenacogrammus flexus, new species, is distinguished from all congeners in the possession of 6 (vs. 7) supraneural bones, and a characteristic zigzag pattern of black pigmentation along and below the midline extending from the posterior border of the opercle to the base of the caudal peduncle. While no unambiguous morphological autapomorphies have been located to diag- nose P. concolor, new species, it is nonetheless readily distinguished from all congeners, except P. deheyni and P. flexus, in the possession of a prominent anterior expansion of the first pleural rib. It differs from both P. deheyni and P. flexus in the absence of a dominant pigmentation patterning over the flanks and caudal peduncle. Additionally, it differs from P. flexus in a shallower body depth (m. 24.9% vs. 27.0% SL) and in the possession of 7 (vs. 6) supraneurals.
... Many small characiforms have reductions in the infraorbital series, and the lack of the supraorbital has been interpreted either as a synapomorphy of a large clade within the Characidae (e.g., Malabarba and Weitzman 2003) or as a synapomorphy of the Characidae when some taxa traditionally assigned to this family are removed and assigned family-level status (e.g., Oliveira et al. 2011). Further reduction in the infraorbital series is usually restricted to one or two missing infraorbitals of those that appear late in the ontogeny of Salminus ), infraorbital 4 and/or 6 (e.g., Weitzman 1954Vari 1979Vari , 1989Weitzman and Fink 1983;Weitzman and Malabarba 1999;Zanata and Vari 2005;Langeani and Serra 2010;Mirande 2010Mirande , 2019Mattox and Toledo-Piza 2012). Extreme reduction in the infraorbital series is rare and includes loss of infraorbitals 4-6 as described here and already reported for miniature characids belonging to other genera such as Iotabrycon (Roberts 1973), Paracheirodon Géry (Weitzman and Fink 1983), Spintherobolus Eigenmann (Weitzman and Malabarba 1999), Amazonspinther Bührnheim, Carvalho, Malabarba and Weitzman (Bührnheim et al. 2008), Trochilocharax Zarske (Zarske 2010), Tyttobrycon Abrahão et al. 2019) and Priocharax (Mattox et al. 2016). ...
Miniaturization, the evolution of extremely small adult body size, is a common phenomenon across the lineages of freshwater fishes, especially in the Neotropics where over 200 species are considered miniature (≤26 mm in standard length [SL]). Close to 30% of all miniature Neotropical freshwater fishes belong to the family Characidae, several of which are of uncertain phylogenetic placement within the family. We investigate the skeletal anatomy of Tucanoichthys tucano , a species of uncertain phylogenetic position from the upper Rio Negro basin, reaching a maximum known size of 16.6 mm SL. The skeleton of Tucanoichthys is characterized by the complete absence of ten skeletal elements and marked reduction in size and/or complexity of others, especially those elements associated with the cephalic latero-sensory canal system. Missing elements in the skeleton of Tucanoichthys include those that develop relatively late in the ossification sequence of the non-miniature characiform Salminus brasiliensis , suggesting that their absence in Tucanoichthys can be explained by a simple scenario of developmental truncation. A number of the reductions in the skeleton of Tucanoichthys are shared with other miniature characiforms, most notably species of Priocharax and Tyttobrycon , the latter a putative close relative of Tucanoichthys based on molecular data.
