[Ichthyology • 2025] Ernstichthys casalinuovoi • A New Species of the Banjo Catfish Genus Ernstichthys (Siluriformes: Aspredinidae) from the Bermejo River Drainage, La Plata Basin, Argentina

 

 Ernstichthys casalinuovoi

Aguilera, Terán, Méndez-López, Montes & Carvalho, 2025

DOI: doi.org/10.1643/i2024072

 Abstract 

The upper Bermejo River basin houses a great diversity of fishes, represented by the endemic species, the shared fauna between the Paraguay and the Amazon basins, and the elements from the Paraná River basin. During recent surveys in the area, many specimens of an undescribed Ernstichthys were collected in four different localities of northwestern Argentina and are herein described as a new species. The new species, Ernstichthys casalinuovoi, is distinguished from the remaining species of the genus by a combination of characters including the number of lateral plates on the body, the shape of the second pre-anal-fin plate, the presence of a rictal barbel, the coloration pattern, the number of total vertebrae, the unbranched maxillary barbel, and the number of serrations on the posterior margin of the pectoral-fin spine, among others. The large batch used to describe Ernstichthys casalinuovoi, new species, has allowed us to detect characters that should be treated carefully in the description of species belonging to Ernstichthys such as the number of serrations on the posterior margin of the pectoral-fin spine or the overlap between bony elements on the caudal peduncle given that they could vary according to ontogeny. The new species herein described represents the fifth species of the genus and the first record of Ernstichthys and the Hoplomyzontinae in Argentina.

 Ernstichthys casalinuovoi, holotype, CI-FML 8098, 34.3 mm SL,
live specimen before fixation.

Ernstichthys casalinuovoi, new species

Gastón Aguilera, Guillermo E. Terán, Alejandro Méndez-López, Martín Miguel Montes and Tiago P. Carvalho. 2025. A New Species of the Banjo Catfish Genus Ernstichthys (Siluriformes: Aspredinidae) from the Bermejo River Drainage, La Plata Basin, Argentina. Ichthyology & Herpetology. 113(3); 527-539. DOI: doi.org/10.1643/i2024072 (3 September 2025) 

https://x.com/IchsAndHerps/status/1965468040268841329

[PaleoIchthyology • 2024] Bunocephalus serranoi • First Fossil Record of Aspredinidae: A New Species from the late Miocene of northeastern Argentina

Bunocephalus serranoi

 Bogan & Agnolin, 2024

 

DOI: doi.org/10.11646/zootaxa.5493.4.5   

 Researchgate.net/publication/383064860

Abstract

This study aims to describe a new fossil species of the extant aspredinid genus Bunocephalus. The new species is represented by a nearly complete skull and pectoral girdle coming from late Miocene Ituzaingó Formation beds of Paraná City, Entre Ríos Province, Argentina. The specimen constitutes the first fossil record for the genus and the family Aspredinidae. This finding demonstrates that large temporal and geographical gaps are still present in the fossil record of the South American continent, evidencing the lack of knowledge of the geographical and temporal distribution of many freshwater fish clades.

Pisces, Ituzaingó Formation, Paraná City, Neogene, Siluriformes, Bunocephalus

Holotype of Bunocephalus serranoi nov. sp. (MAS-PV-795) compared with extant Bunocephalus doriae (CFAIC- 6516) in A, C, dorsal; and B, D, ventral views.

Abbreviations. Cl, cleithrum; Cl S, cleithrum suture; Cor, coracoid; Cor S, coracoid suture; Dor lam Web, dorsal lamina of the Weberian apparatus; Dor P, dorsal process of cleithrum; Hum P, humeral process of cleithrum; Hyo, hyomandibular; Op, opercle Po, preopercle; Scl, supracleithrum; Sp, pectoral spine. Scale bar: 5 mm.

Reconstruction of Bunocephalus serranoi 

 Bunocephalus serranoi nov. sp.

Sergio Bogan and Federico L. Agnolin. 2024. First Fossil Record of Aspredinidae: A New Species from the late Miocene of northeastern Argentina.  Zootaxa. 5493(4);  392-400. DOI: doi.org/10.11646/zootaxa.5493.4.5  

  Researchgate.net/publication/383064860_FIRST_FOSSIL_RECORD_of_ASPREDINIDAE_A_New_Species_from the_Late_MIOCENE_of_NE_ARGENTINA

[Ichthyology • 2024] Re-description of Xyliphius barbatus (Siluriformes: Aspredinidae), with comments on Osteology and Distribution

 Xyliphius barbatus Alonso de Arámburu & Arámburu, 1962, 

in Terán, Méndez-López, Benitez, Serra, Bogan et Aguilera, 2024. 

DOI: 10.3897/zse.100.121396

Abstract

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.

Key Words: Banjo catfish, fossorial fishes, La Plata River basin, morphology, osteology

Lateral, dorsal and ventral views of Xyliphius barbatus. CI-FML 7944. San Francisco River, Bermejo River basin, Jujuy province. Scale bar: 10 mm.

CI-FML 7944. Xyliphius barbatus. Live specimen, 92.4 mm SL. San Francisco River, Bermejo River basin, Jujuy. Scale bar: 10 mm.

 Xyliphius barbatus Alonso de Arámburu & Arámburu, 1962

Diagnosis: Xyliphius barbatus is distinguishable from the remaining species of genus by the following combination of characters: (1) seven to 11 retrorse dentations on posterior margin of pectoral-fin spine (vs. six in X. anachoretes and four or five in X. magdalenae); (2) 24 to 30 dendriform papillae on inferior lip (vs. 20–22 in X. magdalenae, 30 in X. sofiae, and 22 to 27 triangular papillae, with only the lateral ones branched in X. kryptos); (3) I,3 or I,4 dorsal-fin rays (vs. I,5 in X. lepturus and X. melanopterus); (4) absence of dorsal pale band from snout tip to caudal-fin origin (vs. presence in X. anachoretes, X. magdalenae and X. melanopterus); (5) absence of a latero-dorsal band following the second row of tubercles on anterior part of body (vs. present in X. magdalenae and X. melanopterus); (6) eyes present and reduced (vs. absent in X. sofiae); (7) five to eight anal-fin rays (vs. nine in X. lepturus).

 Guillermo E. Terán, Alejandro Méndez-López, Mauricio F. Benitez, Wilson S. Serra, Sergio Bogan and Gastón Aguilera. 2024. Re-description of Xyliphius barbatus (Siluriformes, Aspredinidae), with comments on Osteology and Distribution. Zoosystematics and Evolution. 100(3): 1085-1097. DOI:  doi.org/10.3897/zse.100.121396

[Ichthyology • 2020] Acanthobunocephalus scruggsi • A New Miniature Species of Acanthobunocephalus (Silurifomes: Aspredinidae) from the Lower Purus River Basin, Amazon Basin, Brazil

Acanthobunocephalus scruggsi

 Carvalho & Reis, 2020

DOI: 10.1643/CI-19-309

Abstract

A second species of Acanthobunocephalus is described from tributaries of the lower Purus River in the Amazon Basin, Brazil. Acanthobunocephalus scruggsi, new species, is distinguished from all other aspredinid species by its reduced number of fin rays: four pectoral-fin rays (vs. five or more), two dorsal-fin rays (vs. three or more, except Amaralia hypsiura), five pelvic-fin rays (vs. six), four to five anal-fin rays (vs. six or more, except Bunocephalus verrucosus), and nine caudal-fin rays (vs. 10, except Hoplomyzontinae, Amaralia, Platystacus, Bunocephalus chamaizelus, and Bunocephalus minerim). Osteological aspects of the new species of Acanthobunocephalus are described using cleared and stained specimens and high-resolution x-ray computed tomography (HRXCT), and compared with Acanthobunocephalus nicoi and other aspredinids. Generic assignment is based on putative apomorphic shared features and a morphological diagnosis for Acanthobunocephalus is presented.

Holotype of Acanthobunocephalus scruggsi, INPA 57946, 21.7 mm SL, Brazil, Amazonas, Beruri, Igarapé Caipirinha, tributary of Lago Ayapuá. 

Acanthobunocephalus scruggsi, new species

Etymology.— Acanthobunocephalus scruggsi in named after Earl Scruggs, a prominent American banjo player known for popularizing a three-finger banjo picking style, also known as ‘‘Scruggs style,’’ which is characteristic of bluegrass music. The name of the species also makes an allusion to the common name given to aspredinid species in general (banjo catfishes), and the remarkable resemblance of the new species with this musical instrument.

Tiago P. Carvalho and Roberto E. Reis. 2020. A New Miniature Species of Acanthobunocephalus (Silurifomes: Aspredinidae) from the Lower Purus River Basin, Amazon Basin, Brazil. Copeia. 108(2); 347-357. DOI: 10.1643/CI-19-309

      

[Ichthyology • 2017] Hoplomyzon cardosoi • A New Species of Hoplomyzon (Siluriformes: Aspredinidae) from Maracaibo Basin, Venezuela: Osteological Description Using High-resolution Computed Microtomography of A Miniature Species

Hoplomyzon cardosoi Carvalho, Reis & Friel, 2017

Fig. 1 Hoplomyzon cardosoi, holotype, MCNG 375, 18.5 mm SL, Caño La Raya, Zulia, Venezuela.  Dorsal, left side lateral and ventral views.

DOI: 10.1590/1982-0224-20160143 

ABSTRACT

A new miniature species of banjo catfish of the genus Hoplomyzon is described from the Lake Maracaibo Basin in Venezuela. The new species is distinguished from all its congeners by the straight anterior margin of the mesethmoid (vs. a medial notch); a smooth and straight ventral surface of the premaxilla (vs. presence of bony knobs on the ventral surface of premaxilla); absence of teeth on dentary (vs. teeth present on dentary); configuration of ventral vertebral processes anterior to anal fin, which are composed of single processes anterior to anal-fin pterygiophore (vs. paired process); presence of several filamentous barbel-like structures on the ventral surface of head of adults (vs. small papillous structures in the ventral surface of head of adults); and 8 anal-fin rays (vs. 6 or 7). An extensive osteological description is made of the holotype using high-resolution x-ray computed microtomography (HRXCT).

Keywords: Endemism; Ernstichthys intonsus; Miniaturization; Synapomorphy; Taxonomy

Distribution and habitat. Known from three tributaries, which drain southwestern portions of Lake Maracaibo Basin in Zulia State, Venezuela. The Caño raya at type locality is a medium size stream (~12m wide) with mostly slow flowing white waters running over sand intercalated with riffles of fast flowing waters over pebbles; little marginal and floating vegetation.

Etymology. Hoplomyzon cardosoi is named in honor and memory of a dear colleague who prematurely passed away, Alexandre Rodrigues Cardoso, for his humbleness, positive attitude, and dedicated friendship, and furthermore for his contributions to the taxonomy of Neotropical fishes, including the family Aspredinidae.

Tiago P. Carvalho, Roberto E. Reis and John P. Friel. 2017.  A New Species of Hoplomyzon (Siluriformes: Aspredinidae) from Maracaibo Basin, Venezuela: Osteological Description Using High-resolution Computed Microtomography of A Miniature Species.   Neotropical Ichthyology. 15(1);  DOI: 10.1590/1982-0224-20160143 

[Ichthyology • 2017] Xyliphius sofiae • A New Blind and Rare Species of Xyliphius (Siluriformes: Aspredinidae) from the Amazon Basin, Peru

Xyliphius sofiae 

Sabaj, Carvalho & Reis, 2017

 DOI:  10.1643/CI-16-456  

Xyliphius sofiae, new species, is described based on a unique specimen exhibiting four autapomorphies: eyes absent vs. present (though reduced); color pale, lacking pigment vs. head and body darkly pigmented; branchiostegal rays five vs. four; and unculiferous tubercles on posterior body distributed evenly vs. enlarged unculiferous tubercles typically arranged in five distinct rows above pelvic-fin base to posterior end of caudal peduncle. In addition, the pectoral fin of X. sofiae, new species, has one ossified proximal radial vs. two in congeners (except X. magdalenae, not examined). Xyliphius sofiae, new species, differs from all congeners except X. lepturus by snout tip elongated and narrowly rounded vs. short and broadly rounded, often with small median notch; fifth ceratobranchial relatively narrow with elongate acicular teeth vs. broadly expanded, leaf-shaped, with shorter and broader, conical teeth; anterior limits of branchial apertures separated by distance less than length of aperture vs. greater than length of aperture; anal-fin rays modally nine vs. seven; and lateral line extending onto base of caudal-fin rays vs. finishing in hypural region. Based on the single specimen collected in the main channel of the Río Amazonas near Iquitos, Peru, we describe the osteology of X. sofiae, new species, using a non-invasive technique: high-resolution X-ray computed tomography (HRXCT). We consider Xyliphius lombarderoi Risso and Risso, 1964, a species based on a unique holotype that is now lost, to be a subjective junior synonym of X. barbatus Alonso de Arámburu and Arámburu, 1962. Variable characteristics are summarized for the seven species of Xyliphius treated here as valid, and their distributions are plotted based on a comprehensive review of museum specimens.

Fig. 1. Holotype of Xyliphius sofiae, ANSP 182322, 44.1 mm SL, R´ıo Amazonas in vicinity of Iquitos, Loreto, Peru.
(A–C) Alcohol preserved (scale bar = 5 mm). (D) Live.

Photos by M. Sabaj.   facebook.com/israquarium

Xyliphius sofiae Sabaj, Carvalho and Reis, new species 

Distribution and habitat.— Xyliphius sofiae is known from a single locality in the Amazon River near the town of Iquitos, Peru (Fig. 10). The specimen was collected using a large floating net stretched between two canoes and dragged downstream through the water column.

Etymology.— In honor of the daughter of first author on the specific epithet, for inspiring wisdom in her father.

  Tiago P. Carvalho, Roberto E. Reis and Mark H. Sabaj. 2017. Description of A New Blind and Rare Species of Xyliphius (Siluriformes: Aspredinidae) from the Amazon Basin Using High-Resolution Computed Tomography.  Copeia. 105(1); 14-28. DOI:  10.1643/CI-16-456 

Se describe la especie nueva Xyliphius sofiae basado en un único ejemplar que exhibe cuatro autoapomorfias: ojos ausentes vs. presente (aunque muy reducidos); color pálido, ausencia de pigmento vs. cabeza y cuerpo con pigmentación oscura; cinco radios branquiostegales vs. cuatro; y tubérculos en la parte posterior del cuerpo distribuidos uniformemente vs. tubérculos dispuestas típicamente en cinco filas visibles sobre la región entre la base de la aleta pélvica hasta el pedúnculo caudal. Además, la aleta pectoral de X. sofiae tiene un radial proximal osificado vs dos en sus otros congéneres (no observado en X. magdalenae). Xyliphius sofiae se diferencia de todos sus congéneres, excepto X. lepturus, por la punta del hocico alargado y estrechamente redondeada vs. corto y ampliamente redondeado, a menudo con una pequeña muesca mediana; quinto ceratobranquial relativamente estrecho con los dientes aciculares alargados vs. ampliamente expandidos, en forma de hoja, con dientes cónicos y más amplios; límites anteriores de las aberturas branquiales separadas por la distancia menor que la longitud de la abertura vs. mayor que la longitud de la abertura; los radios de la aleta anal de forma modal nueve vs. siete y la linea lateral extendiendose posteriormente hasta la aleta caudal vs. linea lateral extendiendose posteriormente hasta los hipurales. El único espécimen de X. sofiae depositado en colecciones de museos fue colectado en el canal principal del Río Amazonas cerca de Iquitos, Peru y describimos su osteología utilizando técnicas no invasivas: tomografía computarizada en alta resolución. Xyliphius lombarderoi Risso and Risso, 1964, especie descrita solamente basado en el holotipo que está perdido, es considerado como sinónimo junior de X. barbatus Alonso de Arámburu y Arámburu, 1962. Se resumen características variables de las siete especies de Xyliphius tratadas aquí como válidos, y sus distribuciones se representan gráficamente basadas en una extensiva revisión de especímenes en museos.

[Ichthyology • 2016] Micromyzon orinoco • A New Species of the Blind and Miniature Genus Micromyzon Friel and Lundberg, 1996 (Siluriformes: Aspredinidae) from the Orinoco River: Describing Catfish Diversity Using High-Resolution Computed Tomography

Fig. 2. Micromyzon orinoco, paratype, ANSP 198335, 14.8. mm SL,
Río Orinoco, north-side of Isla Fajardo, opposite Palua, 182 nautical miles from sea bouy, Anzoátegui, Venezuela. Dorsal and ventral views.

DOI:   10.1635/053.165.0104

ABSTRACT

A new species of the aspredinid catfish tribe Hoplomyzontini Micromyzon is described from two specimens collected with trawl nets in two localities, at 10 and 18 m depth, in the main channel of the lower Orinoco River in Venezuela almost 40 years ago. The new species is distinguished from its only congener, Micromyzon akamai, by the: straight anterior margin of the mesethmoid; open posterior cranial fontanel; ossified first pectoral-fin radial; single tubular infraorbital bone; infraorbital sensory canal entering neurocranium via the frontal; enclosed foramen for the abductor superficialis muscle in the coracoid; higher vertebral count (33 vs. 28–32); higher anal-fin ray count (10 or 11 vs. 7–9); and some morphometric features. The holotype of the new species was scanned using High-Resolution X-ray Computed Tomography to illustrate, describe, and compare its bony skeleton to other hoplomyzontins.

 Keywords: Anophthalmic, Miniaturization, Neotropical, River Channels, Taxonomy

Tiago P. Carvalho, John G. Lundberg, Jonathan N. Baskin, John P. Friel and Roberto E. Reis. 2016. A New Species of the Blind and Miniature Genus Micromyzon Friel and Lundberg, 1996 (Siluriformes: Aspredinidae) from the Orinoco River: Describing Catfish Diversity Using High-Resolution Computed Tomography. Proceedings of the Academy of Natural Sciences of Philadelphia. 165(1); 37-53. DOI:   10.1635/053.165.0104

facebook.com/photo.php?fbid=1211085552274567

RESUMEN: Una nueva especie de Hoplomyzontini Micromyzon se describe a partir de dos muestras colectadas con redes de arrastre en dos localidades, entre 10 y 18 metros de profundidad, en el canal principal de la parte baja del Río Orinoco, en Venezuela hace casi 40 años. La nueva especie se diagnostica de su único congénere, Micromyzon akamai, por la margen anterior recta del mesetemoide; parte posterior de la fontanela craneal abierta; el primer radial de la aleta pectoral osificado, un solo hueso infraorbital tubular; el canal sensorial infraorbital entra al neurocráneo a través del frontal; un foramen cerrado para el musculo abductor superficialis en el e coracoide; mayor número de vértebras (33 vs. 28–32) y del número de radios anales (10 o 11 vs. 7–9); además de algunas características morfométricas. El holotipo de la nueva especie fue escaneado en alta resolución utilizando Tomografía Computarizada de Radio-X de Alta Resolución, y se describe su osteología y se compara con otros Hoplomyzontini.

[Ichthyology • 2016] Amaralia oviraptor • A New Species of Amaralia Fowler (Siluriformes: Aspredinidae) from the Paraná-Paraguay River Basin

Amaralia oviraptor

 Friel & Carvalho, 2016

DOI:   10.11646/zootaxa.4088.4.4

Abstract

A new species of the banjo catfish genus Amaralia is described from the Paraná-Paraguay River Basin in central-western Brazil, Paraguay and northern Argentina. Amaralia oviraptor is distinguished from its single and allopatric congener, Amaralia hypsiura, by the greater number of dorsal-fin rays (3 vs. 2); by the absence of lateral contact between middle and posterior nuchal plates (vs. middle and posterior nuchal plates contacting each other laterally); and by a longer cleithral process (17.4–19.5 % of SL, mean 18.2 % vs. 14.0–17.2 % of SL, mean=15.5 %). Comments on the peculiar oophagic diet of Amaralia and an extended diagnosis of the genus are provided.

Keywords: Pisces, Neotropical, biodiversity, banjo catfish, osteology, oophagy

FIGURE 1. Amaralia oviraptor, MZUSP 4423, holotype, 68 mm SL
Brazil, Mato Grosso, Santo Antônio do Leverger municipality, rio Cuiabá.

 facebook.com/photo.php?fbid=10102905279169055

Distribution. Amaralia oviraptor is widely distributed in the Paraná-Paraguay River system, found throughout the Paraguay River Basin in Brazil, Paraguay and northern Argentina and also in the Paraná drainage in Argentina and Brazil (Fig. 8). The new species seems to be absent in some portions of this system such as the Uruguay River Basin and the main tributaries of the upper Paraná.

Etymology. The epithet oviraptor is a combination of the Latin ovum (ovi), meaning egg; and raptor, a robber or plunderer, commonly used term for a predator, here referring to the peculiar dietary preferences observed in this species. Treated as a noun in apposition.

Ecological notes. An interesting aspect of Amaralia is its apparent dietary specialization on both the eggs and developing embryos of other catfishes (Friel, 1994; Roberts, 2015). Direct evidence of such oophagy is based on examination of the stomach contents from 23 preserved Amaralia specimens (17 A. hypsiura and six A. oviraptor ). Seven of these specimens (six female and one male) contained masses of ova or developing embryos in their stomach. The source of the eggs and embryos is most likely those of loricariid catfishes, and in least in one instance, the caudal fin-ray counts of the embryos fall within the range for loricariid catfishes. One male contained a single scoloplacid catfish specimen in its stomach, and the remaining 15 specimens (seven female and eight male) had empty stomachs. These observations differ significantly from the documented diets of other aspredinids, where stomach contents typically contained some organic detritus along with various aquatic and terrestrial insect prey.

John P. Friel and Tiago P. Carvalho. 2016. A New Species of Amaralia Fowler (Siluriformes: Aspredinidae) from the Paraná-Paraguay River Basin. Zootaxa. 4088(4) 

http://www.mapress.com/j/zt/article/view/zootaxa.4088.4.4

ResearchGate.net/publication/297746030_A_new_species_of_Amaralia_Fowler_Siluriformes_Aspredinidae_from_the_Parana-Paraguay_River_Basin

Resumo: 
Uma nova espécie de Amaralia é descrita da bacia do Paraná-Paraguai no Centro-Oeste do Brasil, Paraguai e Norte da Argentina. Amaralia oviraptor difere-se do seu único congênere de distribuição alopátrica, Amaralia hypsiura, pelo maior número de raios da nadadeira dorsal (3 vs. 2); pela ausência de um contato lateral entre a placa nucal mediana e a placa nucal posterior (vs. placa mediana e posterior contatando uma a outra lateralmente); e por um processo cleitral mais longo (17.4–19.5 % do CP, média = 18.2 % vs. 14.0–17.2 % do CP, média = 15.5 %). Comentários sobre o gênero são feitos acerca de sua dieta oofágica e uma diagnose entre os aspredinídeos é fornecida. 
Palavras-chave: Neotropical, biodiversidade, bagre banjo, osteologia, oofagia.