[Ichthyology • 2026] Arhinoglanis relictus • Phylogenetic Assessment and Taxonomic Description of the First Scale-feeding Candiru (Siluriformes: Trichomycteridae) from west of the Andes

 

Arhinoglanis relictus

DoNascimiento, Ortega-Lara, Albornoz-Garzón, Román-Valencia & Lujan, 2026

  

DOI: doi.org/10.1093/zoolinnean/zlag002  

  x.com/DrNathanLujan

Abstract

Among vertebrates, specialized scale-feeding occurs almost exclusively in tropical freshwater fishes, with the Amazon basin having the richest regional assemblage of such specialists. With 28 valid species and 11 valid genera, 10 of which are ectoparasitic scale and mucus-feeders, the Neotropical trichomycterid subfamily Stegophilinae is the only fish lineage to have significantly diversified within this niche. Stegophilines are widespread and ubiquitous throughout the lowland freshwaters of South America, east of the Andes. We describe Arhinoglanis gen. nov. and Arhinoglanis relictus sp. nov., the first Stegophilinae from west of the Andes, from the upper Cauca River drainage, Colombia. At 26.4 mm maximum standard length, the new genus and species is also the first miniature Stegophilinae. Using diaphanization, light microscopy, and micro-computed tomography imagery, we coded 534 morphological characters for 50 terminal taxa to recover the new taxon as sister to the exclusively cis-Andean clade of Homodiaetus + Schultzichthys. A single unique synapomorphy unites these genera: proximal tip of ceratobranchial 5 wider than proximal tip of ceratobranchial 4. Five autapomorphies diagnose the new genus, the most notable of which is a paedomorphically unossified dorsal lamina of the mesethmoid. The scarcity and highly restricted distribution of the new species within the Magdalena basin has led to its evaluation as Critically Endangered.

catfish, Cauca River, morphology, Neotropics, Stegophilinae, systematics

Arhinoglanis relictus, live paratype, ROM 112325, 20.9 mm SL, in lateral (A) and dorsal (B) views.

 A, ventral photo of live paratype of Arhinoglanis relictus, ROM 112325, 20.9 mm SL, showing gut content, and CT reconstructions of same specimen in (B) ventral and (C) left lateral views, with magnified gut content in (D) ventral, (E) dorsal, and (F) left lateral views.

Scale bars (left) = 5 mm, (right) = 1 mm.

 Arhinoglanis gen. nov. 

Arhinoglanis relictus sp. nov.

 

Carlos DoNascimiento, Armando Ortega-Lara, Juan G Albornoz-Garzón, César Román-Valencia and Nathan K Lujan. 2026. Phylogenetic Assessment and Taxonomic Description of the First Scale-feeding Candiru from west of the Andes (Siluriformes, Trichomycteridae). Zoological Journal of the Linnean Society. 206(3); zlag002. DOI: doi.org/10.1093/zoolinnean/zlag002 [15 March 2026]

  x.com/DrNathanLujan/status/2033293332143636918

[Ichthyology • 2025] Ituglanis jussariensis • New insights into Ituglanis (Siluriformes: Trichomycteridae) Diversity in Bahia State, eastern Brazil: Description of A New Species and conservation status reappraisal

Ituglanis jussariensis

Vilardo, Katz & Costa, 2025

 DOI: doi.org/10.1111/jfb.70246 

 

Abstract

The northeastern Atlantic Forest of Brazil harbours a remarkable diversity of species of Trichomycteridae, many of which remain poorly understood. This study describes a new species of Ituglanis, endemic to the Ribeirão São Roque, a stream tributary of Rio Piabanha, an affluent of Rio Colônia basin, Bahia State, Brazil. The new species is distinguished from its congeners by a combination of the following characters: four pairs of ribs; 35 post-Weberian vertebrae, seven pectoral-fin rays; and a colour pattern consisting of irregular dark brown spots along the flanks and dorsal region. The specimens were encountered during field studies conducted in southern Bahia State aimed at collecting Ituglanis cahyensis and Ituglanis agreste. However, despite extensive efforts, neither of these species was found during surveys, suggesting potential population declines. Additionally, we reassess the conservation status of the species of Ituglanis from Bahia State, proposing status updates for three of the four previously described species based on recent field data and habitat assessments. The discovery of this new species underscores the urgent need for further exploration and collection in poorly sampled areas of the Atlantic Forest. Human activities, including deforestation and habitat degradation, continue to threaten these unique ecosystems. As demonstrated here, the description of new species contributes not only to a better understanding of biodiversity and evolutionary relationships within Ituglanis but also to conservation efforts in one of the most endangered biodiversity hotspots in the world.

Keywords: Atlantic Forest, biodiversity, catfish, conservation status, Neotropics, systematics

Ituglanis jussariensis holotype. UFRJ 14477, 42.0 mm SL, stream tributary to Rio São Roque drainage, Rio Piabanha basin. Left lateral, dorsal and ventral views.

Ituglanis jussariensis sp. n. Vilardo, Katz and Costa.

Etymology: The specific name jussariensis refers to Jussari Municipality where the new species was discovered and collected.

Ituglanis jussariensis live holotype and paratype.
(a) UFRJ 14477, holotype, 42.0 mm SL. (b) UFRJ 13135, paratype, 44.0 mm SL.

(a,b) Rio São Roque drainage, Rio Piabanha basin, Jussari Municipality, Bahia State, Brazil, the type locality of Ituglanis jussariensis.

Paulo J. Vilardo, Axel M. Katz and Wilson J. E. M. Costa. 2025. New insights into Ituglanis (Siluriformes: Trichomycteridae) Diversity in Bahia State, eastern Brazil: Description of A New Species and conservation status reappraisal. Journal of Fish Biology. DOI: doi.org/10.1111/jfb.70246 [05 October 2025]

[Ichthyology • 2020] Trichomycterus vitalbrazili • A New Species of Trichomycterus (Siluriformes: Trichomycteridae) from the Rio Paraíba do Sul Basin, South-eastern Brazil

 

Trichomycterus vitalbrazili Vilardo,

in Vilardo, Katz et Costa, 2020 

 DOI: 10.6620/ZS.2020.59-53 

  Researchgate.net/publication/345681406

A phylogenetic analysis using fragments of two nuclear and two mitochondrial genes strongly supported sister group relationships between a new species and Trichomycterus albinotatus, corroborated by unique colour patterns of adult specimens and juveniles, and morphology of the autopalatine bone. The new species is distinguished from its closest congener, T. albinotatus, by details of the colouration and number of branchiostegal rays. Both the new species and T. albinotatus are endemic to the Rio Paraíba do Sul basin, in the Atlantic Forest of south-eastern Brazil, but occur in distant and disjunct areas. The new species, herein described, is endemic to the upper section of the Rio Grande drainage, a right tributary of the lower Rio Paraíba do Sul, an area situated in the Órgãos Mountain Range. Trichomycterus albinotatus is endemic to an area about 200 km across, in the upper section of the Rio Preto that drains the Itatiaia Massif. However, both species are only known from localities above 1100 m asl, suggesting that they cannot survive in ecological conditions at lower altitudes. This study indicates that efforts are necessary to provide more accurate data on the species diversity and distribution of Trichomycterus in the biologically diverse and endangered Atlantic Forest of south-eastern Brazil.

Key words: Atlantic Forest, Biodiversity, Catfish, Molecular phylogeny, Neotropics, Systematics

Trichomycterus vitalbrazili. Brazil: Rio de Janeiro State: Nova Friburgo Municipality: Rio Paraíba do Sul basin.
(a) UFRJ 12151, 88.0 mm SL (preserved holotype), left lateral view; (b) UFRJ 12151, 88.0 mm SL (live holotype), left lateral view. Caudal-fin margin of holotype is damaged, see figure 6 for correct information of caudal morphology

Trichomycterus vitalbrazili. Brazil: Rio de Janeiro State: Nova Friburgo Municipality: Rio Paraíba do Sul basin.
(a), UFRJ 12125, 24.1 mm SL (live juvenile paratype), left lateral view; (b) UFRJ 12125, 29.1 mm SL (live juvenile paratype), left lateral view; and (c) UFRJ 12125, 29.1 mm SL (live juvenile paratype), dorsal view. Arrow indicates the midline row with white spots, which is not visible in left lateral view of figure 3b due to the light angle.

Trichomycterus vitalbrazili sp. nov. Vilardo,

Diagnosis: Trichomycterus vitalbrazili is distinguished from all other congeners except T. albinotatus by the presence of a vertical row of dark brown to black spots on the caudal peduncle end, often coalesced to form a precaudal bar in live and preserved specimens (Fig. 2A–B; vs. never a similar colour pattern); two horizontal rows of white spots on the flank in live juveniles (Fig. 3A–C; vs. never a similar colour pattern); and medial margin of the autopalatine nearly straight to slightly convex (Fig. 4A; vs. concave). Trichomycterus vitalbrazili is distinguished from T. albinotatus (Fig. 5A–B) by possessing diffuse irregularly shaped dark brown blotches on the flank in adult specimens (Fig. 2A–B; vs. well-delimited dark grey to black, sometimes coalesced in larger specimens); fins with dark brown spots in adults specimens (Fig. 2A–B; vs. without spots); and eight branchiostegal rays (vs. seven)

Etymology: The name vitalbrazili was given in honour of Vital Brazil Mineiro da Campanha (1865– 1950), an important Brazilian biomedical scientist who first discovered the polyvalent anti-ophidic serum, successfully used to treat venomous snake bites, and founded the Vital Brazil Institute, where the new species was found. 

Stream tributary to the Grande river drainage, Rio Paraiba do Sul basin, inside the advanced campus of Instituto Vital Brazil in São Lourenço road, the type locality of Trichomycterus vitalbrazili.

Paulo J. Vilardo, Axel M. Katz and Wilson J. E. M. Costa. 2020. Relationships and Description of a New Species of Trichomycterus (Siluriformes: Trichomycteridae) from the Rio Paraíba do Sul Basin, South-eastern Brazil. Zoological Studies. 59(53). DOI: 10.6620/ZS.2020.59-53 (2020.10.13)

  Researchgate.net/publication/345681406_a_New_Species_of_Trichomycterus_from_the_Rio_Paraiba_do_Sul_basin_Brazil

  

 

[Ichthyology • 2018] Copionodon elysium • A New Species of Copionodon (Siluriformes: Trichomycteridae) lacking a free orbital rim

Copionodon elysium

 de Pinna, Burger & Zanata, 2018 

 

DOI: 10.1590/1982-0224-20170146 

ABSTRACT

A new species of the copionodontine genus Copionodon is described from the upper reaches of a tributary to the rio Paraguaçu in the Diamantina Plateau, Bahia State, northeastern Brazil. This species represents the northernmost occurrence of the subfamily yet known. The new species can be readily recognized by its large eye without a free orbital rim. Other characters such as the entirely cartilaginous second hypobranchial, and the uniformly broad irregular midlateral dark band further diagnose the new taxon. Its particular combination of characters is superficially intermediate between Copionodon and Glaphyropoma. Detailed analysis, however, indicates that it forms a monophyletic group with species of Copionodon and therefore it should be included in that genus.

Key-words: Chapada Diamantina; Endemicity; New taxon; Rio Paraguaçu; Systematics; Taxonomy

Copionodon elysium, new species

Diagnosis. Distinguished from all other copionodontine catfishes by the large eye without a free orbital rim (Figs. 1, 2; vs. large eyes and free orbital rim in Copionodon spp. or with small eyes but without a free orbital rim in Glaphyropoma spp.). Also, uniquely diagnosed in the subfamily by the second hypobranchial entirely cartilaginous (Fig. 3; vs. presence of a conical ossification cap in the anterolateral corner of the second hypobranchial in other copionodontines) and the reduced or vestigial adipose fin in adults, resulting in a dorsal profile of the caudal peduncle almost straight (Fig. 1; vs. caudal peduncle dorsally convex as a result of the well-developed adipose fin). Further distinguished from congeners by the thin upper and lower lips, with lower lip not flattened ventrally, continuous and not split in two halves by medial depression (Fig. 2b; vs. broader lips and presence of median constriction on lower lip), mouth inferior, located close to anterior margin of snout (vs. mouth distinctly ventral, located posterior to anterior margin of snout), and by the posteriorly-positioned dorsal fin (predorsal distance 56.7-61.7 % of SL vs. 46.0-55.0 % of SL). The new species is also distinguished by its color pattern, with an uniformly broad midlateral dark (Fig. 1; vs. narrow dark band in C. pecten, somewhat broad and asymmetrical dark band in C. lianae, or absence of dark lateral band in remaining copionodontines). Copionodon elysium further differs from C. pecten by the smaller interopercular patch of odontodes, distant from lower lip anteriorly and not reaching opercular aperture (Fig. 2b; vs. interopercular patch of odontodes large, extending from near lower lip anteriorly to beyond pectoral-fin insertion posteriorly) and longer barbels, with maxillary barbel usually reaching pectoral-fin origin and rictal one extending beyond midlength of interopercular patch of odontodes (vs. maxillary barbel reaching posterior ¼ of length of interopercular patch of odontodes and rictal reaching anterior ¼ of length of interopercular patch of odontodes). From the species of Glaphyropoma, the new taxon further differs by a series of characters, including the broad hypobranchial (Fig. 3; vs. slender), the caudal fin bilobed (Fig. 1; vs. truncate), the toothed portion on dentary not reaching the coronoid process (Fig. 4; vs. reaching coronoid process), and the presence of asymmetrical spatulate teeth in jaws (Fig. 4; vs. all teeth symmetrically spatulate).

 Collection site of Copionodon elysium, Riacho Águas Claras, near Morrão, Bahia, Brazil.

Geographical distribution. Copionodon elysium is known exclusively from riacho Águas Claras, a stream of approximately 6 km, tributary of rio Mucugezinho, itself a tributary of rio Santo Antonio, upper rio Paraguaçu basin, Chapada Diamantina, Bahia State, Brazil (Fig. 6).

Ecological notes. The Águas Claras stream is perennial and torrential in the rainy season. Its headwaters are around 1000 m above sea level and it runs on the western slopes of the Sincorá Range, partly within the Chapada Diamantina National Park. The population has a patchy distribution in the stream, with individuals concentrating in certain stretches and entirely absent in others. Copionodon elysium was sampled in slow-flowing stretches over solid rock bottom or boulders, with riffles and shallow pools 10-30 centimeters deep and 1-3 meters wide (Fig. 7), with water transparent and tea-stained, though not to the same darkness as is typical in the Chapada Diamantina. Shallow pools have accumulations of plant debris along the margin. Marginal vegetation is typical “Campo Rupestre”, an herbaceous-shrub vegetation type that develops at elevations of about 900 m on sandstones and quartzite. Shrubs of Bonnetia stricta (Nees) Nees, Mart. (Bonnetiaceae) dominate the margins along the stretches sampled. The only other fish species collected with C. elysium was Astyanax sp.

The analysis of stomach contents of three specimens of C. elysium includes allochthonous and autochthonous items, composed mainly of aquatic insects (Trichoptera: larvae of Hydroptilidae and Hydropsychidae; Diptera: larvae of Simuliidae and Chironomidae; adult coleopterans; Plecoptera eggs), filamentous algae, and fragments of adult terrestrial insects (Hymenoptera: Formicidae), and numerous sand grains.

Considering the pristine condition of the type locality and its location inside an official preservation area, there are no evident threats to the survival of C. elysium, despite its narrowly endemic distribution and probably small population size.

Etymology. The specific epithet comes from the Greek elysium, in reference to the mythological Elysean Fields: a place or condition of ideal happiness; a state or place of perfect bliss. This alludes to the locality inhabited by the new species, a scenic pristine place (Fig. 7) shared with a single other fish species and no fish predators. A noun in apposition.

  

Mario de Pinna, Rafael Burger and Angela Maria Zanata. 2018. A New Species of Copionodon lacking a free orbital rim (Siluriformes: Trichomycteridae). Neotrop. ichthyol. 16(2); DOI: 10.1590/1982-0224-20170146 

 

  

RESUMO: Uma nova espécie do gênero Copionodon, subfamília Copionodontinae, é descrita para o trecho superior de um tributário do Rio Paraguaçu na Chapada Diamantina, Estado da Bahia, nordeste do Brasil. Este registro representa a ocorrência mais ao norte de Copionodontinae até agora conhecido. A nova espécie pode ser facilmente reconhecida por ter olho grande sem margem orbital livre. Outras características como o segundo hipo-branquial inteiramente cartilaginoso e uma faixa escura lateral irregular de largura uniforme também servem para diagnosticar o táxon. A combinação particular de caracteres do novo táxon é superficialmente intermediária entre Copionodon e Glaphyropoma. Entretanto, uma análise mais detalhada indica que forma um grupo monofilético com Copionodon e portanto deve ser incluída neste gênero.

Palavras-chave: Chapada Diamantina; Endemicidade; Novo Táxon; Rio Paraguaçu; Sistemática; Taxonomia

[Ichthyology • 2020] Cambeva flavopicta • A New Species from subtropical Brazil and Evidence of Multiple Pelvic Fin Losses in Catfishes of the Genus Cambeva (Siluriformes: Trichomycteridae)

 Cambeva flavopicta

Costa, Feltrin & Katz, 2020

 DOI: 10.3897/zse.96.56247

Abstract

A third pelvic-less species of Cambeva from river basins draining the Geral mountain range in southern Brazil is described. It is distinguished from other congeners lacking pelvic fin and girdle, C. pascuali and C. tropeiro, by having six pectoral-fin rays, 20–23 dorsal procurrent caudal-fin rays, 15–20 opercular and 25–30 interopercular odontodes and a different colour pattern consisting of flank dark brownish-grey with two irregular horizontal rows of small pale yellow grey marks. Whereas available molecular evidence indicates that C. pascuali is more closely related to C. zonata, a species with well-developed pelvic fin, and C. tropeiro is more closely related to C. balios, another species also with well-developed pelvic fin; osteological data strongly suggest that the new species herein described is more closely related to C. diatropoporos than to other congeners. Therefore, this study indicates that the pelvic fin and pelvic-fin support have been lost independently in each of these three species of Cambeva, which corresponds to 11% of all describe species. This result highly contrasts with the closely-related trichomycterine genera Trichomycterus, in which only one in 50 species lost pelvic fin and girdle (0.2%) and Scleronema with all the nine included species having well-developed pelvic fin. These data suggest a stronger tendency to losing pelvic fin in Cambeva, but factors favouring this evolutionary event are still unknown.

Key Words: Mountain biodiversity, osteology, Rio Uruguai basin, Serra Geral, systematics

 Cambeva flavopicta sp. nov., UFRJ 12665, holotype, 69.2 mm SL:
A. Left lateral view; B. Dorsal view; C. Ventral view.

Cambeva flavopicta sp. nov.

Diagnosis: Cambeva flavopicta is distinguished from all other congeners, except C. pascuali and C. tropeiro, by the absence of pelvic fin and pelvic girdle (vs. pelvic fin and girdle present and well-developed). It is distinguished from both C. pascuali and C. tropeiro by having 6 pectoral-fin rays (vs. 5 in C. pascuali and 7 in C. tropeiro), more dorsal procurrent caudal-fin rays (20–23 vs. 17–18 in C. pascuali and 14–15 in C. tropeiro), more opercular odontodes (15–20 vs. 10–12 in C. pascuali and 12–14 in C. tropeiro), more interopercular odontodes (25–30 vs. 11–12 in C. pascuali and 18–24 in C. tropeiro) and colour pattern consisting of flank dark brownish-grey with two irregular horizontal rows of small pale yellow grey marks (vs. flank pale yellow with dark brown stripes or horizontal rows of spots in C. pascuali and flank yellowish-brown with dark brown spots irregularly arranged in C. tropeiro). Cambeva flavopicta also differs from C. pascuali by the presence of the anterior section of the infra-orbital canal (vs. absence), more vertebrae (38–39 vs. 37) and more branchiostegal rays (9 vs. 7); and from C. tropeiro by having more ventral procurrent caudal-fin rays (16–17 vs. 10–11), the first pectoral-fin ray terminating in a short filament (vs. without a filament) and caudal fin rounded (vs. subtruncate).

 

Rio Inferno Grande (upper Rio Uruguai basin, Santa Catarina, Brazil), at the exact point where the holotype and paratypes of  Cambeva flavopicta sp. nov. were collected.

Distribution and habitat: Cambeva flavopicta is only known from the upper Rio Inferno Grande and tributaries, Rio Canoas drainage, upper Rio Uruguai basin, southern Brazil (Fig. 3). The collecting sites were typical mountain rivers draining the Serra Geral, with fast flowing waters (Fig. 4). The species was found close to the riverbank, buried below marginal vegetation.

Etymology: From the Latin, the name flavopicta (painted with yellow) refers to the characteristic colouration of this new species, with yellow marks over dark brown ground.

Map of geographical distribution of  Cambeva flavopicta sp. nov. (triangle), and type localities of C. diatropoporos (diamond), C. pascuali (pentagon), C. poikilos (star) and C. tropeiro (dot).

Wilson J. E. M. Costa, Caio R. M. Feltrin and Axel M. Katz. 2020. A New Species from subtropical Brazil and Evidence of Multiple Pelvic Fin Losses in Catfishes of the Genus Cambeva (Siluriformes, Trichomycteridae).  Zoosystematics and Evolution. 96(2): 715-722. DOI: 10.3897/zse.96.56247

[Ichthyology • 2023] Trichomycterus puna • A New Species of Trichomycterus (Siluriformes: Trichomycteridae) from Wetlands of High Elevation of Argentina, with Notes on the T. alterus Species-Complex

Trichomycterus puna

Fernández, Contrera & Bize, 2023

DOI: 10.1643/i2022074 

 twitter.com/IchsAndHerps

 

Abstract

Trichomycterus puna, new species, is described from a small tributary of the Corral Blanco in Catamarca Province, Argentina, as part of an ongoing systematic study of the genus Trichomycterus from the High Andean Plateau or Altiplano-Puna drainages of the southern Central Andes. The new species is distinguished from congeners by the following characters: the odontodes embedded in thick integument that covers interopercle, the premaxillary bone smaller than maxilla, the presence of sesamoid supraorbital with lateral process, the supraorbital sensory pore s3 present, the discontinuous supraorbital sensory canal, 2–3 premaxillary tooth rows, the uniformly dark pigmentation on the trunk, 15 precaudal vertebrae, the skin of trunk with minute thread-like papillae, 7–8 pectoral-fin rays, 9–12 dorsal procurrent caudal-fin rays, 10–11 ventral procurrent caudal-fin rays, the distally unbranched barbels, the wider interorbital distance, 16 pairs of ribs, the first dorsal-fin pterygiophore inserting on vertebra 18, and the first anal-fin pterygiophore inserting on vertebra 21. It closely resembles T. alterus, T. belensis, T. boylei, and T. ramosus from the Puna region. Trichomycterus belensis and T. catamarcensis are recorded from new localities over 3,400 m elevation.

Trichomycterus puna, holotype, FACEN 151, 74.1 mm SL, Argentina, Provincia Catamarca, Departamento Bele´n, El Angosto creek.

Trichomycterus puna, new species

Etymology.—The specific epithet puna is a noun in apposition and is attributable to the geological province known as the Puna. The origin of the word is Quechuan and is attributable to the indigenous people known as the Kollas who lived in this area.

 

 Luis Fernández, Guadalupe Contrera and Julieta Andreoli Bize. 2023. New Species of Trichomycterus (Siluriformes: Trichomycteridae) from Wetlands of High Elevation of Argentina, with Notes on the T. alterus Species-Complex. Ichthyology & Herpetology. 111(3); 456-466. DOI: 10.1643/i2022074

  twitter.com/IchsAndHerps/status/1711757073728303518

[Ichthyology • 2023] Rhinotridens chromocaudatus • A New Genus and Species of miniature tridentine Catfish (Siluriformes: Trichomycteridae) from the Amazon Basin

Rhinotridens chromocaudatus

 Datovo, Ochoa, Vita, Presti, Ohara & de Pinna, 2023

 www.ni.bio.br/1982-0224-2023-0076

DOI: 10.1590/1982-0224-2023-0076  

   facebook.com/NeotropicalIchthyology

Abstract

A new miniature tridentine catfish is described from the rio Purus drainage, Amazon basin, Brazil. It differs from all other tridentines in having several unique autapomorphies: conspicuous anteromedial protuberance in the snout; set of symphyseal premaxillary and dentary teeth inclined posteromedially; distal process of the hyomandibula directed anteriorly; rod-like orbitosphenoid ossified only ventral to the optic nerve; mesethmoid cornua inclined ventrolaterally; opercular and interopercular odontodophores separated by a large interspace; basipterygia fused sagittally; and conspicuous dark brown horizontal stripe in the middle of the caudal fin. The new taxon is hypothesized to be sister to the clade formed by Tridensimilis and Tridens. A detailed osteological description of the new taxon is provided based on X-ray microcomputed tomography (µCT-scans) data and on cleared and stained specimens. Our analysis also reveals that “Tridens” brevis, an enigmatic species that has been indecisively assigned to three different tridentine genera over the past 134 years, belongs to Tridentopsis.Consequently, Tridensimilis is a monotypic genus that currently includes only T. venezuelae.

Keywords: Freshwater; Loricarioidei; Ostariophysi; Systematics; Taxonomy

Rhinotridens, new genus

 

Type-species. Rhinotridens chromocaudatus, new species.

Diagnosis. Rhinotridens is distinguished from all other tridentine genera by the following unique autapomorphies: presence of a conspicuous anteromedial protuberance on the snout, with a length greater than 35% of its width (Fig. 1; vs. protuberance absent or limited to a discreet convexity with a length less than 18% of its width; see Baskin, 1973: fig. 66; Henschel et al., 2023: figs. 2, 8, 12, 13); set of symphyseal premaxillary and dentary teeth inclined posteromedially (Fig. 2; vs. not inclined, see Azpelicueta, 1990: figs. 2, 3; Henschel et al., 2023: fig. 9); rod-like orbitosphenoid ossified only ventral to the optic nerve (Fig. 3; vs. laminar bone ossified around the optic nerve, with a foramen for its exit, see Baskin, 1973: figs. 28, 29; Henschel et al., 2023: fig. 3); mesethmoid cornua inclined ventrolaterally (Fig. 4; vs. cornua horizontally straight); distal process of the hyomandibula directed anteriorly (Fig. 5; vs. posteriorly, see Baskin, 1973: fig. 51; Henschel et al., 2017: fig. 2g; Henschel et al., 2023: fig. 4); opercular and interopercular odontodophores separated by a large interspace, greater than the depth of the opercular patch (Fig. 5; vs. patches nearly juxtaposed, separated by a distance less than the depth of the opercular patch, see Baskin, 1973: fig. 51; Azpelicueta, 1990: fig. 4; Henschel et al., 2017: fig. 2g; Henschel et al., 2023: fig. 4); and basipterygia fused sagittally (Fig. 6; vs. separated).

 

Etymology. From rhino, latinized form of the Greek word rhinos (ῥινός), meaning nose or snout, and Tridens, the type genus of the subfamily. In allusion to the rostral protuberance of the new genus. An adjective.

Rhinotridens chromocaudatus, new species

 

Diagnosis. The new species differs from all other tridentines by having a conspicuous dark brown horizontal stripe in the middle of the caudal fin (Fig. 1). Ongoing studies indicate the existence of additional undescribed species of Rhinotridens that lack this caudal stripe (see Discussion). As a result, this character is preemptively proposed as autapomorphic for R. chromocaudatus rather than as a synapomorphy for the genus as a whole.

Etymology. From chroma, latinized form of the Greek word khrôma (χρῶμα), meaning color, and cauda, a Latin word meaning tail. In reference to the presence of the dark brown pigmentation in the middle of the caudal fin. An adjective.

Alessio Datovo, Luz Ochoa, George Vita, Paulo Presti, William M. Ohara and Mario C. C. de Pinna. 2023. A New Genus and Species of miniature tridentine Catfish from the Amazon Basin (Siluriformes: Trichomycteridae). Neotrop. ichthyol. 21(3); www.ni.bio.br/1982-0224-2023-0076

DOI: 10.1590/1982-0224-2023-0076   

  facebook.com/NeotropicalIchthyology/posts/827294132732968

[Ichthyology • 2023] Ituglanis crispim • Filling in A Biogeographic Gap: the First Trichomycteridae (Siluriformes) from the Parnaíba River Basin

Ituglanis crispim

Donin, de Pinna, Severi & Ramos, 2023

DOI: 10.1590/1982-0224-2023-0018  

Abstract

Trichomycterid catfishes have long been considered as absent in the Parnaíba River basin, Northeastern Brazil, in what constitutes their most conspicuous gap in geographic distribution. Herein we report on the first occurrence of the family in that basin. The new species is described from the riacho da Volta, right tributary to the upper rio Parnaíba, Piauí State. It is distinguished from its congeners by the combination of two or three pairs of ribs; 36–38 post Weberian vertebrae; a color pattern composed of round, similar-sized, non-coalescent spots; I,5 pectoral-fin rays; the first haemal arch on the 5th or 6th vertebrae; and the first completely fused (to the tip) haemal spine on the 15th vertebra. A putative autapomorphy is the partial (minimally 50% of their length) or total fusion between the anterior arms of the basipterygium. Preliminary evidence suggests that the new species can be related to northern South American forms, a pattern that fits the general Amazonian relationships of the fishes in the Parnaíba River drainage. Although the new species fills in an important qualitative gap in trichomycterid continental distribution, the taxon is apparently rare and extremely restricted in distribution, with the type series being its only record so far. The paucity of trichomycterids in the Parnaíba remains a puzzling biogeographical phenomenon.

Keywords: Ituglanis; New species; Taxonomy; Trichomycterinae

Ituglanis crispim, MZUSP 126762, holotype, 28.8 mm SL,
riacho da Volta, right tributary to Parnaíba River, Parnaíba River basin.
Left lateral, dorsal, and ventral views.

Ituglanis crispim, new species 

Ituglanis sp. —Ramos et al., 2014:04 

[listed to Parnaíba River basin].

 

Diagnosis. Ituglanis crispim is distinguished from all congeners by the combination of the following characters: two or three pairs of ribs; 36–38 post Weberian vertebrae; a color pattern composed of round, uniformly-sized, evenly-spaced, non-coalescent spots; I,5 pectoral-fin rays; the first haemal arch on the 5th or 6th vertebra; the first completely fused (to the tip) haemal spine on 15° vertebrae. The presence of two or three pairs of ribs (vs. four pairs or more) distinguish the species from all congeners with the exception of I. amazonicus (Steindachner, 1882), I. apteryx Datovo, 2014, I. compactus Castro & Wosiacki, 2017, I. eichhorniarum (Miranda Ribeiro, 1912), I. gracilior (Eigenmann, 1912), I. herberti (Miranda Ribeiro, 1940), I. ina Wosiacki, Dutra & Mendonça, 2012, I. inusitatus Ferrer & Donin, 2017, I. macunaimaDatovo & Landim, 2005, I. metae(Eigenmann, 1917), I. nebulosusde Pinna & Keith, 2003, and I. parkoi(Miranda Ribeiro, 1944). The count of 36–38 post Weberian vertebrae distinguish I. crispim from I. amazonicus, I. apteryx, I. gracilior, I. herberti, I. inusitatus, I. metae, and I. parkoi, all with 39 or more vertebrae. The pigmentation pattern composed by round, similar-sized, non-coalescent dark spots, slightly larger than eye (vs. color patterns either uniform, or mottled with irregular-sized spots or partly coalescent markings, or blotched, sometimes forming longitudinal strips) separates I. crispim from congeners, except for I. amazonicus, I. gracilior, I. guayaberensis, I. macunaima, and I. metae. The presence of I,5 pectoral-fin rays distinguishes I. crispim from I. agreste Lima, Neves & Campos-Paiva, 2013, I. apteryx, I. bambui Bichuette & Trajano, 2004, I. boticario Rizzato & Bichuette, 2015, I. cahyensis Sarmento-Soares, Martins-Pinheiro, Aranda & Chamon, 2006, I. goya, I. epikarsticus Bichuette & Trajano, 2004, I. guayaberensis (Dahl, 1960), I. herberti, I. inusitatus, I. laticeps (Kner, 1863), I. gracilior, I. macunaima, I. mambai Bichuette & Trajano, 2008, I. paraguassuensis Campos-Paiva & Costa, 2007, I. parahybae (Eigenmann, 1918), I. parkoi, I. passensis Fernández & Bichuette, 2002, I. payaya (Sarmento-Soares, Zanata & Martins-Pinheiro 2011), I. proops (Miranda Ribeiro, 1908), and I. ramiroi Bichuette & Trajano, 2004, all with I,4; I,6 or more. The first haemal arch on 5th or 6th vertebrae distinguishes I. crispim from I. bambui (10th,12th), I. boticario (8th), I. compactus (4th), I. epikarsticus (7th, 9th), I. goya (9–10th), I. nebulosus (4th), and I. ramiroi (7th, 8th, 10th); the first complete haemal spine on 15th vertebra distinguishes I. crispim from I. amazonicus (17th), I. australis Datovo & de Pinna, 2014 (12–13th), I. eichhorniarum (16th, 18th), I. epikarsticus (13–14th), I. goya, (16th, 18th), I. gracilior (16th, 17th, 20th), I. nebulosus (16th), I. payaya (14th), I. paraguassuensis (12th), I. passensis (14th), I. proops (14th), and I. ramiroi (12–14th), (the latter two characteristics have been verified in limited samples of some species, intraspecific variation may be larger than recorded). A putatively autapomorphic character for the new species is the partial or total fusion between the anterior arms of the basipterygium (united minimally for 50% of their length) (Fig. 2).

 A. Type locality of Ituglanis crispim, riacho da Volta, right tributary to Parnaíba River, Uruçuí, Parnaíba River basin, Piauí, Brazil.
B. In detail the submerged filamentous algae. Photo taken on July 18, 2005.

Etymology. The specific epithet was given in reference to the Crispim, known for the local tragedy-legend “Cabeça de Cuia”. Having murdered his own mother, Crispin was cursed and turned into a horrific aquatic creature with a gigantic “cuia” (bowl-shaped) head, condemned to perpetually wander the Parnaíba River and only to be redeemed after devouring seven virgins named Maria. A noun in apposittion.

 

Laura M. Donin, Mário C. C. de Pinna, William Severi and Telton P. A. Ramos. 2023. Filling in A Biogeographic Gap: the First Trichomycteridae from the Parnaíba River Basin (Siluriformes: Trichomycteridae).   Neotrop. ichthyol. 21(2); DOI: 10.1590/1982-0224-2023-0018    

[Ichthyology • 2023] Cambeva piraquara • A New Species of Cambeva (Siluriformes: Trichomycteridae) from An Area of High Anthropogenic Impacts in the Headwaters of Rio Iguaçu, Southern Brazil

Cambeva piraquara 

 dos Reis, Wosiacki, Ferrer, Donin & da Graça, 2023

DOI: 10.1139/cjz-2022-0150 

 twitter.com/RenanB__Reis 

 

Abstract

Cambeva piraquara, sp. nov., a restricted-range and rare species last collected from over 20 years ago, is described from the Rio Piraquara, upper Rio Iguaçu basin, Rio Paraná (La Plata) system. The new species is distinguished from all congeners by having two conspicuous dark-brown longitudinal stripes on the inner skin layer of body over a plain yellowish background: a conspicuous wide and well-defined dark-brown longitudinal mid-lateral stripe extending from the opercular patch of odontodes to the first third of caudal-fin rays and a dorso-sagittal stripe comprising large and coalescent rounded blotches extending from occipital to the dorsal-fin base. We provide an illustrated osteological description and assess the conservation status of the new species, which faces several environmental impacts in the upper Rio Iguaçu basin.

Cambeva piraquara sp. nov. holotype: MPEG 39144, 41.6 mm SL,
Brazil, Paraná State, Piraquara, Rio Piraquara, a tributary of Rio Timbu, upper Rio Iguaçu basin, Rio Paraná system.

 Cambeva piraquara, sp. nov.

Etymology: The specific epithet “piraquara” is an indigenous word that means “fish hole” from the Tupi language: pira = fish and kuara = hole, cave, cavity, or hiding place (Ferreira 2006). The Piraquara River is also the type locality of the new species, a noun in apposition.

 

Renan B. dos Reis, Wolmar B. Wosiacki, Juliano Ferrer, Laura M. Donin and Weferson J. da Graça. 2023. A New Species of Cambeva (Siluriformes: Trichomycteridae) from An Area of High Anthropogenic Impacts in the Headwaters of Rio Iguaçu, Southern Brazil.  Canadian Journal of Zoology. DOI: 10.1139/cjz-2022-0150

  twitter.com/RenanB__Reis/status/1638189188125278208

 Researchgate.net/publication/369375051_A_new_species_of_Cambeva_from_the_headwaters_of_Rio_Iguacu_Southern_Brazil

[Ichthyology • 2022] Cambeva gamabelardense • An Endangered New Catfish Species of the Genus Cambeva (Siluriformes: Trichomycteridae) from the Rio Chapecó drainage, southern Brazil

Cambeva gamabelardense

Costa, Feltrin & Katz, 2022

DOI:  10.32800/abc.2022.45.0123

 

Numerous species in fast–flowing streams of southern Brazil have not been described to date. As some of these species inhabit areas under pressure due to the ongoing, intense process of environmental degradation, formal descriptions are urgently needed so as to elaborate strategies for their conservation. We describe a new species, Cambeva gamabelardense n. sp., found in the middle Rio Chapecó drainage, Uruguay River basin, in an area where intense deforestation and soya plantation is endangering fish species. The new species is considered closely related to C. panthera, a species occurring in an isolated coastal basin about 380 km from the area inhabited by the new species, as the two species share a unique jaguar–like pattern on the flank. The new species differs from C. panthera by having shorter barbels, a different position of the origin of the dorsal–fin, more vertebrae, and osteological features that are unique among congeners.

Keywords: Cambeva gamabelardense n. sp., Comparative morphology, Mountain biodiversity, Osteology, Uruguay River basin

Cambeva gamabelardense n. sp., holotype, UFRJ 7003, 107.2 mm SL:
A, lateral view; B, dorsal view; C, ventral view.

Class Actinopterygii Klein, 1885 

Order Siluriformes Cuvier, 1817 

Family Trichomycteridae Bleeker, 1858 

Cambeva gamabelardense n. sp. (figs. 1–2)

Diagnosis: Cambeva gamabelardense is distinguished from all other congeners, except C. panthera Costa, Feltrin and Katz, 2021, by having a jaguar–like colour pattern on the flank, consisting of irregularly shaped pale brown spots of variable size and shape, with their margins overlapped by small dark brown spots (fig. 1; vs. never a similar colour pattern). Cambeva gamabelardense differs from C. panthera by having shorter barbels, with the tip of the maxillary and rictal barbels reaching the middle portion of the interopercular patch of odontodes (vs. the tip of the maxillary barbel reaching the middle of the pectoral–fin base and the tip of the rictal barbel reaching between the interopercular patch of odontodes and the pectoral–fin base) and the tip of the nasal barbel reaching between the eye and the opercular patch of odontodes (vs. the tip of the nasal barbel reaching the middle of opercular patch of odontodes); the first pectoral–fin ray terminating in a rudimentary filament, weakly extending beyond the fin membrane (vs. filament about 10–15% of the pectoral–fin length); the posterior extremity of the pelvic fin at a vertical through the anterior portion of the dorsal–fin base (vs. middle portion); the dorsal–fin origin at a vertical through the centrum of the 20th or 21st vertebra (vs. through the centrum of the 18th or 19th vertebra); and 38 or 39 vertebrae (vs. 37). Cambeva gamabelardense differs from all other trichomycterines examined by its long metapterygoid, its horizontal length longer than the horizontal length of hyomandibula anterior outgrowth (fig. 2B; vs. shorter) and a small lateral projection on the lateral margin of the lateral ethmoid, just posterior to the articular facet for the autopalatine (fig. 2A; vs. absence of a similar projection).

Distribution: Cambeva gamabelardense n. sp. is only known from the type locality area, in the upper Rio Chapecó drainage, Rio Uruguai basin, at altitudes between about 750 and 860 m a.s.l. (fig. 3).

Etymology: The name gamabelardense (gamma, the third letter of the Greek alphabet, and abelardense, a Portuguese word referring to people born in Abelardo Luz municipality) is an allusion to the third new species of Cambeva known to occur in this area. The other two species are described in Costa et al. (2022).  

W. J. M. Costa, C. R. M. Feltrin and A. M. Katz. 2022. An Endangered New Catfish Species of the Genus Cambeva (Cambeva gamabelardense n. sp.) (Siluriformes, Trichomycteridae) from the Rio Chapecó drainage, southern Brazil. Animal Biodiversity and Conservation. 45.1: 123-129. DOI:  10.32800/abc.2022.45.0123