[Ichthyology • 2024] Urkumayu gen. nov. & ‘Hoplisoma’ osvaldoi • Integrative Phylogeny of Corydoradinae (Siluriformes: Callichthyidae) with an emphasis on Northwestern La Plata Species, including Descriptions of A New Genus and Species

  

Urkumayu micracanthus  (Regan 1912)
Urkumayu gladysae (Calviño & Alonso 2010) 

Urkumayu, new genus 

Alonso, Terán, Aguilera, Montes, Serra Alanís, Calviño, Vera-Alcaraz, Cardoso, Koerber & Mirande, 2024

DOI: doi.org/10.1016/j.jcz.2024.11.006

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Highlights

• New phylogenetic hypothesis for diverse Neotropical fish genus Corydoras

• Integration of molecular and morphological data from 153 species

• Discovery of a new clade, including Andean and upper Paraná basin species

• Identification of emerging endemicity hotspots in NW La Plata basin

• Description of a new species and assessment of conservation status

Abstract

The knowledge about the diversity and phylogeny of South American callichthyid armored catfishes of the subfamily Corydoradinae is still growing, after important recent contributions, and many species have uncertain relationships. In this study, we present the first combined phylogenetic hypothesis for the genus based on five genes, 83 morphological characters, and 153 species, providing synapomorphies for some of the main genera of Corydoradinae, as recently defined. The inclusion of species not previously analyzed in a phylogenetic context challenged the monophyly of Hoplisoma and required the definition of a new genus for endemic species from the Andean portion of the northwestern La Plata basin (ANWLP): Hoplisoma gladysae, H. micracanthum, and H. petracinii. We found Hoplisoma non monophyletic with Hoplisoma sensu stricto not sister to a clade of species herein named the ‘Hoplisoma’ paleatum clade. In this clade we recovered a new species of Hoplisoma, which is endemic to the upper Bermejo basin, as sister to ‘Hoplisoma’ paleatum from the lower La Plata basin. The new species is distinguished from all congeners by a unique coloration similar to that of the syntopic H. micracanthum, suggesting a putative case of Müllerian co-mimicry.

Key words: Müllerian co-mimicry, coloration, endemic species, Upper Bermejo, threatened species

 Live individuals. (A)  Urkumayu micracanthus (CI-FML 7014, 30.3 mm SL).
(B) Urkumayu gladysae (CI-FML 8109, 30.1 mm SL).
(C) Urkumayu petracinii (CI-FML 8110, 26.9 mm SL).

Urkumayu, new genus Alonso, Terán, Aguilera, Montes, Serra Alanís, Calviño, Vera-Alcaraz, Cardoso, Koerber, Mirande

 

Type species: Corydoras gladysae Calviño & Alonso 2010

Diagnosis: Urkumayu is distinguished from the remaining genera of Corydoradinae by the following unique combination of characters: supraoccipital and nuchal plate not in contact, posterior expansion of pharyngobranchial triangular, and ossified portion of pectoral spine strongly reduced.

Included species: Urkumayu gladysae (Calviño & Alonso 2010) n. comb., Urkumayu micracanthus (Regan 1912) n. comb., Urkumayu petracinii (Calviño & Alonso 2010) n. comb.

Etymology: Urkumayu, masculine gender, from the Quechua language, compound of urku meaning mountain and mayu for river, referring to the habitat where most species of this genus are found.

Distribution: It has a disjunct distribution in northwestern Andean La Plata Basin in Argentina.

 ‘Hoplisoma’ osvaldoi n. sp. alive individual immediately after capture (CI-FML 5360, 41.6 mm SL). 
 ‘Hoplisoma’ osvaldoi n. sp. (left) (CI-FML 5360, 41.6 mm SL) and Urkumayu micracanthus (right) (CI-FML 7011, 28.8 mm SL) immediately after capture. Anta Muerta creek (-23.117134 S, -64.497133 W).

 Hoplisoma osvaldoi, new species Alonso, Terán, Aguilera, Montes, Serra Alanís, Calviño, Vera-Alcaraz, Cardoso, Koerber, Mirande

Etymology: The specific epithet honors Jorge Osvaldo Fernández Santos, an esteemed aquarist and fish collector who made significant contributions to the knowledge of Argentinean fish by collecting and generously donating numerous specimens to scientific collections and collaborating with ichthyologists. He had been an avid promoter of the fish keeping hobby, particularly with respect to native species. As a result, this species is named in recognition of Osvaldo’s contributions to the study and knowledge of Argentina’s fishes.

Felipe Alonso, Guillermo Enrique Terán, Gastón Aguilera, Martin Miguel Montes, Wilson Sebastián Serra Alanís, Pablo Calviño, Héctor Samuel Vera-Alcaraz, Yamila Cardoso, Stefan Koerber and Juan Marcos Mirande. 2024. Integrative Phylogeny of Corydoradinae (Siluriformes: Callichthyidae) with an emphasis on Northwestern La Plata Species, including Descriptions of A New Genus and Species. Zoologischer Anzeiger. In Press. DOI: doi.org/10.1016/j.jcz.2024.11.006

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[Ichthyology • 2024] Corydoras caramater • A New long-snouted Corydoras (Siluriformes: Callichthyidae) from the rio Xingu and rio Tapajós Basins, Brazilian Amazon

Corydoras caramater 

 Tencatt, Couto, Santos & Sousa, 2024

DOI: 10.1590/1982-0224-2023-0112  

  

Abstract

A new species of Corydoras is described from the rio Xingu and rio Tapajós basins, Pará State, Brazil. The new species can be promptly distinguished from its congeners by the combination of the following features: (I) temporal sensory canal at sphenotic with two pores; (II) upper tooth plate of branchial arch with three or four series of teeth; (III) area at the corner of the mouth, ventral to the maxillary barbel, with a small, roughly triangular fleshy flap, not forming an elongated barbel-like structure; (IV) contact between posterior process of the parieto-supraoccipital and nuchal plate; (V) dark stripe transversally crossing the orbit, forming a mask-like blotch; (VI) absence of a distinct color pattern along midline of flank; (VII) dorsolateral body plates only with small, irregular, rounded or vertically elongated dark brown or black blotches; ground color of plates typically dusky but not forming large, conspicuous black patches; and (VIII) absence of a relatively large, conspicuous dark patch on anterior portion of dorsal fin.

Keywords: Corydoradinae; Corydoras sp. CW83; Jacareacanga; Taxonomy; Volta Grande do Xingu

Specimens of Corydoras caramater from the rio Tapajós basin photographed alive in lateral view, showing general color pattern and morphology of (A) an uncatalogued specimen from the rio Pacu with paler background color of body, (B) an uncatalogued specimen from igarapé Sonrisal with slightly darker background color of body, and (C) a non-type specimen (CPUFMT 8149, 1, 49.9 mm SL) from the rio Pacu with clearly darker background color of body. Photos by William Ohara.

  Uncatalogued aquarium specimens of Corydoras caramater from the rio Tapajós basin photographed alive, showing general color pattern and morphology of a male (A) and of a female (B) specimens. Photos by Hans Evers.

Corydoras caramater, new species

Diagnosis: Corydoras caramater can be distinguished from its congeners, except for the species within the lineage 1 sensu Alexandrou et al. (2011), by the presence of the following features: branch of the temporal sensory canal at sphenotic, which gives rise to the supraorbital canal, with two pores (vs. one pore); upper tooth plate of branchial arch with three or four series of teeth (vs. two series); and area at the corner of the mouth, ventral to the maxillary barbel, with a small fleshy flap (vs. fleshy flap absent); from the lineage 1 species, except for C. amapaensis Nijssen, 1972, C. blochi Nijssen, 1971, C. cortesi Castro, 1987, C. desana Lima & Sazima, 2017, C. pastazensis Weitzman, 1963, C. saramaccensis Nijssen, 1970, C. septentrionalis Gosline, 1940, C. serratus Sands, 1995, C. solox Nijssen & Isbrücker, 1983, and C. simulatus Weitzman & Nijssen, 1970, by having a dark brown or black patch transversally crossing the orbit, forming a mask-like blotch, which can be variably diffuse (vs. mask-like blotch absent); it differs from C. cortesi, C. desana, C. pastazensis, C. septentrionalis, and C. simulatus by the absence of a distinct color pattern along midline of flank (vs. midline of flank with moderate- to large-sized, conspicuous dark brown or black blotches in C. desana, C. pastazensis, C. septentrionalis, and C. simulatus; with a longitudinal dark brown or black stripe in C. cortesi); from C. amapaensis, C. serratus and C. solox, it differs by having dorsolateral body plates only with small, irregular, rounded or vertically elongated dark brown or black blotches; ground color of plates typically dusky but not forming large, conspicuous black patches (vs. midventral portion of dorsolateral body plates on region between middle portion of dorsal fin and caudal-fin base typically with large, conspicuous dark brown or black longitudinally elongated blotch or stripe; dark stripe variably diffuse, in C. amapaensis; wide, dark brown or black longitudinal stripe from predorsal region to caudal-fin base or, alternatively, dorsolateral body plates around anterior portion of dorsal-fin base with dark brown or black patch in C. serratus; region between anterior portion of dorsal fin and caudal-fin base with wide, longitudinal dark brown or black stripe in C. solox); from C. blochi and C. saramaccensis by the absence of a relatively large, conspicuous dark patch on anterior portion of dorsal fin (vs. anterior portion of dorsal fin with a conspicuous concentration of dark brown or black chromatophores, forming a relatively large, conspicuous patch). Additionally, Corydoras caramater can be distinguished from C. geoffroy Lacépède, 1803, C. amapaensis, C. septentrionalis, and C. solox by having a triangular fleshy flap at the corner of mouth, ventrally to maxillary barbel, not forming an elongated barbel-like structure (vs. fleshy flap at corner of mouth elongated, forming a barbel-like structure).

Etymology. The specific epithet caramater is formed by the junction of two words derived from the Latin ‘cara’, which means dear, beloved, and ‘mater’, meaning mother. This is a small tribute to these strong women, who work hard and are still responsible, often alone, for tenderly raising their children. The name especially honors Miriam Tencatt, Jéssica Mendonça (mother and wife of LCFT, respectively), Ireide da Silva Pinto (mother of OLPC), Vanda Santos (in memorian), Roberta Murta-Fonseca (mother and wife of SAS, respectively), and Edina Melo de Sousa (mother of LMS), but extends to all caring mothers around the world. A noun in apposition.

L.F.C. Tencatt, Couto O.L.P., Santos S.A. and Sousa L.M. 2024. A New long-snouted Corydoras (Siluriformes: Callichthyidae) from the rio Xingu and rio Tapajós Basins, Brazilian Amazon.  Neotrop. ichthyol. 22(1); DOI: 10.1590/1982-0224-2023-0112    

[Ichthyology • 2023] Corydoras colossus • A New color-changing Species of Corydoras (Siluriformes: Callichthyidae) from the rio Jutaí, Brazilian Amazon

 Corydoras colossus

 Tencatt, Grant & Bentley, 2023

 DOI: 10.1590/1982-0224-2023-0105 

Photos by Hans Evers &  Steven Grant

 

Abstract

A new species of Corydoras is described from the rio Jutaí, Amazon basin, Brazil. The new species can be distinguished from its congeners by having the following features: (I) ventral surface of trunk entirely or almost entirely covered by small- to relatively large-sized coalescent platelets, forming a typical mosaic-like pattern; (II) large, arched dark brown or black patch extending from interopercle region to posterior process of parieto-supraoccipital, transversally crossing the orbit and forming a typical mask-like blotch; (III) absence of conspicuous dark markings on caudal fin; (IV) absence of longitudinal rows of dark blotches on flanks; (V) region of first dorsolateral body plate surrounding posterior process of parieto-supraoccipital clearly lighter than remaining portions of head, forming a V-shaped pattern in dorsal view; (VI) anterior portion of dorsal fin with a conspicuous dark patch; and (VII) anterior portion of dorsal-fin base with conspicuous concentration of dark brown or black chromatophores, forming a dark patch slightly darker than ground color of body. A discussion on the possible positive adaptive value of the color pattern is also provided.

Keywords: Aposematism; Corydoradinae; Corydoras sp. CW45; Crypsis; Taxonomy

Variations in color pattern in life of Corydoras colossus in lateral view, showing the general color pattern in life of the holotype (A);
MNRJ 54421, 44.5 mm SL), a paratype with a paler pattern (B); not labelled as photographed after preservation, catalog number untraceable),
and of an uncatalogued aquarium specimen (not measured) with a darker pattern (C).

Photos by Steven Grant.

Corydoras colossus, new species

Corydoras sp. CW045. —Alexandrou, Taylor, 2011:115 

(“CW45”; phylogeny; member of lineage 9). —Fuller, Evers, 2011:88 (code number).

Diagnosis. Corydoras colossus can be distinguished from its congeners, except for C. araguaiaensis Sands, 1990, C. burgessi Axelrod, 1987, C. concolor Weitzman, 1961, C. esperanzae Castro, 1987, C. evelynae Rössel, 1963, C. eversi Tencatt & Britto, 2016, C. granti Tencatt, Lima & Britto, 2019, C. julii Steindachner, 1906, C. melanistius Regan, 1912, C. oiapoquensis Nijssen, 1972, C. parallelus Burgess, 1993, C. pavanelliae Tencatt & Ohara, 2016, C. polystictus Regan, 1912, C. schwartzi Rössel, 1963, C. surinamensis Nijssen, 1970, C. trilineatus Cope, 1872, and C. xinguensis Nijssen, 1972, by having ventral surface of trunk with small- to relatively large-sized coalescent platelets, forming a typical mosaic-like pattern (vs. platelets on ventral surface of trunk, when present, small-sized and not coalescent, not forming a mosaic-like pattern). The new species can be distinguished from C. araguaiaensis, C. eversi, C. granti, C. julii, C. pavanelliae, C. polystictus, C. trilineatus, and C. xinguensis by the presence of a large, arched dark brown or black patch extending from interopercle region to posterior process of parieto-supraoccipital, transversally crossing orbit and forming typical mask-like blotch (vs. mask-like blotch absent); from C. evelynae, C. oiapoquensis, C. schwartzi, and C. surinamensis by the absence of conspicuous dark markings on caudal fin (vs. caudal fin with conspicuous dark brown or black blotches, which are typically roughly transversally aligned, forming bars); from C. parallelus plus C. evelynae, C. schwartzi and C. surinamensis by the absence of longitudinal rows of dark blotches on flanks (vs. at least two rows of conspicuous dark blotches roughly longitudinally aligned on flanks, which can be variably fused, forming stripes); from C. concolor and C. esperanzae by having region of first dorsolateral body plate surrounding posterior process of parieto-supraoccipital clearly lighter than remaining portions of head, forming a V-shaped pattern in dorsal view (vs. absence of a V-shaped pale area on predorsal region of body) and by presenting anterior portion of dorsal fin with conspicuous concentration of dark brown or black chromatophores, forming a dark patch (vs. dorsal fin uniformly colored, not forming dark patches or blotches); from C. burgessi and C. melanistius plus C. parallelus and C. surinamensis by having the anterior portion of dorsal-fin base with conspicuous concentration of dark brown or black chromatophores, forming a dark patch slightly darker than ground color of body (vs. dark patch on dorsal-fin base well defined, conspicuously standing out of the ground color of body). The new species can be further distinguished from C. burgessi, C. melanistius, C. oiapoquensis, C. parallelus, C. pavanelliae, C. polystictus, and C. surinamensis by having mosaic-like pattern of plates entirely or almost entirely covering ventral surface trunk (vs. mosaic-like pattern of plates restricted to some portions of ventral surface trunk, representing up to about 50% of its area).

 Breeding pair (A), female on the left and male on the right, plus an ontogenetic series of  Corydoras colossus (bred under aquarium conditions) showing general changes in external morphology and color pattern in specimens with (B) 9.0 mm TL, (C) 13.0 mm TL; (D) 17.0 mm TL, and (E) 22.0 mm TL.

Photos by Hans Evers.

Etymology. The specific epithet “colossus” derives from the Ancient Greek κολοσσός (kolossós), which means “large/giant statue”, alluding to the relatively large, robust, armored body of the new species. A noun in apposition.

Luiz Fernando Caserta Tencatt, Steven Grant and Rebecca Frances Bentley. 2023. A New color-changing Species of Corydoras (Siluriformes: Callichthyidae) from the rio Jutaí, Brazilian Amazon. Neotrop. ichthyol. 21(04); DOI: 10.1590/1982-0224-2023-0105 

[Ichthyology • 2022] Aspidoras aldebaran • Taxonomy of the Armored Catfish Genus Aspidoras (Siluriformes: Callichthyidae) revisited, with the Description of A New Species

 

Aspidoras aldebaran

 Tencatt, Britto, Isbrücker & Pavanelli, 2022

 DOI: 10.1590/1982-0224-2022-0040   

Photos by Hans Evers.

 

Abstract

Aspidoras comprises 25 species currently considered as valid, being widely distributed in Brazil, occurring from the upper rio Paraná basin in São Paulo to coastal basins of Ceará. After Nijssen, Isbrücker’s review more than 40 years ago, no extensive work regarding the taxonomy of Aspidoras was conducted. Our paper presents a comprehensive taxonomic revision of the genus, based primarily on the extensive material that has been collected since then. Considering the new diagnosis plus the available phylogenetic data, A. pauciradiatus and A. virgulatus are transferred to Corydoras and Scleromystax, respectively. New synonymies are proposed: A. eurycephalus and A. taurus with A. albater; A. menezesi and A. spilotus with A. raimundi; and A. microgalaeus and A. marianae with A. poecilus. Additionally, a new species from the Araguaia and Paraguay river basins is described, which can be distinguished from its congeners by the morphology of its complex vertebra and infraorbital 1. Thereby, the number of valid species within Aspidoras was reduced from 25 to 18. Redescriptions for A. albater, A. belenos, A. depinnai, A. fuscoguttatus, A. lakoi, A. maculosus, A. poecilus, A. psammatides, A. raimundi, and A. velites are provided. An identification key to the species of Aspidoras is also provided.

Keywords: Aspidoradini; Corydoradinae; Identification key; Osteology; Taxonomy

Aspidoras Ihering, 1907

Aspidoras Ihering, 1907:30–31 

(original description; type species: Aspidoras rochai Ihering, 1907, 

by original designation and monotypy). 

—Nijssen, Isbrücker, 1976:107‒131 (taxonomic review). 

—Reis, 1998:161 (diagnosis in identification key). 

—Britto, 2003:144, 146‒147 (phylogeny; diagnosis). 

—Reis, 2003:291 (listed). 

—Ferraris, 2007:108 (listed).

Type species. Aspidoras rochai Ihering, 1907, by original designation and monotypy.

Diagnosis. Aspidoras can be distinguished from Corydoras and Scleromystax by presenting an exclusive feature among Corydoradinae: base of pectoral-fin branched rays with small laminar expansions on its inner margin, generally more evident on first rays; laminar expansions with irregular margins, forming pointed structures, in some specimens (vs. absence). Additionally, Aspidoras can be distinguished from Corydoras and Scleromystax, with exception of Corydoras pauciradiatus, C. lacerdai and S. virgulatus, by having parieto-supraoccipital fontanel (vs. fontanel absent); from C. pauciradiatus, C. lacerdai and S. virgulatus by presenting extremely reduced to moderately developed pectoral-fin spine (vs. relatively well developed).

Aspidoras aldebaran, uncataloged specimen photographed alive (A), and the córrego Gordura, rio Araguaia basin, showing the typical habitat of the new species (B).

Photos by Hans Evers.

 

Aspidoras aldebaran, new species

Diagnosis. Aspidoras aldebaran can be distinguished from its congeners, with exception of A. belenos, A. kiriri, and A. raimundi, by having parapophysis of the complex vertebra well developed (vs. moderately developed in A. depinnai, A. lakoi, A. maculosus, A. mephisto, A. poecilus, A. psammatides, and A. velites; poorly or moderately developed in A. albater and A. fuscoguttatus; poorly developed in A. azaghal); it can be distinguished from A. belenos, A. kiriri, and A. raimundi by having inner laminar expansion of infraorbital 1 ranging from well developed to extremely well developed (vs. moderately developed). Additionally, it can be distinguished from A. albater, A. azaghal, A. gabrieli, A. lakoi, A. mephisto, A. psammatides, and A. rochai by having a narrow frontal bone, with width slightly smaller than half of entire length (vs. relatively wide, with width equal to or slightly larger than half of entire length in A. albater, A. azaghal, A. gabrieli, A. lakoi, A. mephisto, and A. rochai; extremely narrow, with width conspicuously smaller than half of entire length in A. psammatides); from A. azaghal, A. depinnai and A. kiriri by the presence of small black spots on dorsal fin (vs. absence).

Etymology. The epithet “aldebaran” refers to the red giant Aldebaran or Alpha Tauri (α Tauri), the brightest star of the Taurus constellation, deriving from the Arabic al Dabarān, which means “the follower”. The star presents a bright orange glow and it is positioned at the left eye of the mythological bull. The name alludes to the fact that A. aldebaran was firstly found among Aspidoras taurus type series (see Remarks below), being promptly recognized as a different and new species by its peculiar morphology and color pattern. A noun in apposition.

 

Luiz Fernando Caserta Tencatt, Marcelo R. Britto, Isaäc Jan Hendrik Isbrücker and Carla Simone Pavanelli. 2022. Taxonomy of the Armored Catfish Genus Aspidoras (Siluriformes: Callichthyidae) revisited, with the Description of A New Species.  Neotrop. ichthyol. 20(03); DOI: 10.1590/1982-0224-2022-0040   

[Ichthyology • 2023] Corydoras maclurei • A New Species of Corydoras (Siluriformes: Callichthyidae) from the rio Madre de Dios Basin, Peruvian Amazon, with Comments on Corydoras aeneus Identity

Corydoras maclurei

Tencatt, de Carvalho Gomes & Evers, 2023

DOI: 10.1590/1982-0224-2023-0023 

Abstract

A new species of Corydoras is described from tributaries to the rio Araza, an affluent of the rio Inambari, itself a tributary to the rio Madre de Dios, rio Madeira basin in the Peruvian Amazon. The new species can be distinguished from its congeners by the following features: (I) absence of contact between the posterior process of the parieto-supraoccipital and the nuchal plate, (II) a single, large conspicuous dark brown or black blotch on anterodorsal portion of flank; blotch somewhat rounded to roughly diamond shaped, and (III) absence of dark blotches on fins. General comments on the identity of Corydoras aeneus are also provided.

Keywords: Corydoradinae; Corydoras sp. CW16; Osteology; Rio Madeira basin; Taxonomy

Corydoras maclurei, holotype, MUSM 70671, 37.0 mm SL,
Camanti District, Quispicanchi Province, Cusco Region, Peru, small stream tributary to the rio Araza, a bigger affluent of the rio Inambari, itself a tributary to the rio Madre de Dios, rio Madeira basin.

Uncatalogued aquarium specimens of Corydoras maclurei (not measured) showing variations of the color pattern in life:
specimens can variably present greyish orange (A) or reddish orange (B) ground color of body. In C, the detail of a conspicuously reddish orange dorsal fin. Anterior portion of first dorsolateral body plate typically with orange (D) or yellow (E) bright patch. Photographs (D) and (E) by Ian Fuller.

Uncatalogued aquarium specimen of Corydoras maclurei (A) showing its typical color pattern in life (lateral view),
collected in its type-locality (B), a small stream tributary to the rio Araza, rio Madre de Dios basin, rio Madeira basin in Peru.

Corydoras maclurei, new species

Diagnosis. Corydoras maclurei can be distinguished from its congeners, except for C. difluviatilis Britto & Castro, 2002, C. flaveolus Ihering, 1911, C. gladysae, C. gracilis Nijssen & Isbrücker, 1976, C. hastatus Eigenmann & Eigenmann, 1888, C. hephaestus Ohara, Tencatt & Britto, 2016, C. latus, C. melanotaenia Regan, 1912, C. micracanthus Regan, 1912, C. nanus, C. petracinii, C pygmaeus Knaack, 1966, and C. undulatus Regan, 1912, by the absence of contact between the posterior process of the parieto-supraoccipital and the nuchal plate (vs. bones in contact). The new species can be distinguished from C. difluviatilis, C. flaveolus, C. gladysae, C. gracilis, C. hastatus, C. hephaestus, C. latus, C. melanotaenia, C. micracanthus, C. nanus, C. petracinii, C pygmaeus, and C. undulatus by having just a single, large conspicuous dark brown or black blotch on anterodorsal portion of flank; ...

Etymology: Corydoras maclurei is named in honor of Robert “Rob” McLure, dear friend and renowned Corydoradinae breeder. Rob has been the main English-language reviewer of the first author’s publications, in addition to providing valuable information and live photos of several species of Corydoradinae. A genitive noun.

Luiz Fernando Caserta Tencatt, Vandergleison de Carvalho Gomes and Hans-Georg Evers. 2023. A New Species of Corydoras (Siluriformes: Callichthyidae) from the rio Madre de Dios Basin, Peruvian Amazon, with Comments on Corydoras aeneus Identity.  Neotrop. ichthyol. 21 (2); DOI: 10.1590/1982-0224-2023-0023   

 

Resumo: Uma espécie nova de Corydoras é descrita de tributários do rio Araza, um afluente do rio Inambari, por sua vez um tributário do rio Madre de Dios, bacia do rio Madeira na Amazônia peruana. A espécie nova pode ser distinguida de suas congêneres pelas seguintes características: (I) ausência de contato entre o processo posterior do parieto-supraoccipital e a placa nucal, (II) uma única e conspícua mancha marrom escura a preta na porção anterodorsal do flanco; mancha algo arredondada a aproximadamente em forma de diamante, e (III) ausência de manchas escuras nas nadadeiras. Comentários gerais sobre a identidade de Corydoras aeneus são também fornecidos.

Palavras-chave: Bacia do rio Madeira; Corydoradinae; Corydoras sp. CW16; Osteologia; Taxonomia

[Ichthyology • 2021] Corydoras bethanae • A New Arc-striped Species of Corydoras Lacépède, 1803 (Siluriformes: Callichthyidae) from the Peruvian Amazon

A. Corydoras bethanae, female holotype, río Blanco, Department of Loreto, Peru.
B. Corydoras arcuatus unpreserved aquarium specimen.

 

Bentley, Grant & Tencatt, 2021

DOI: 10.11646/zootaxa.4948.2.2 

 Researchgate.net/publication/350186091 

Photos by Steven Grant & Hans-Georg Evers.

Abstract

A new Corydoras is described from the Blanco and Ucayali river basins in Peru. The new species can be distinguished from its congeners by having the following features: (I) posterior margin of dorsal-fin spine with laminar serrations directed towards the origin of the spine; (II) a long, wide, arched, and continuous black stripe, which runs parallel to the dorsal profile of the body, extending at least from the region below anterior origin of dorsal fin to the anterior half of the ventral caudal-fin lobe; (III) a black stripe transversally crossing the eye, forming the typical mask-like blotch; mask clearly not fused to arched stripe in most specimens; some specimens with mask separated from arched stripe by a thin line around the suture between neurocranium (in the region composed by the posteroventral margin of parieto-supraoccipital plus the posterodorsal margin of the compound pterotic) and first dorsolateral body plate; (IV) posterior margin of pectoral-fin spine with laminar serrations directed towards the origin of the spine; (V) pointed snout, presenting a long mesethmoid, with anterior tip larger than 50% of the entire length of the bone; and (V) ventral surface of trunk covered by small, non-coalescent platelets. A discussion on the possible positive adaptive value of the arc-striped color pattern is also provided.

Keywords: Pisces, Aposematism, Corydoradinae, mimicry, río Blanco, taxonomy

 

FIGURE 2. A. Corydoras bethanae, holotype alive, MUSM 69403, female, 51.2 mm SL, Peru, Department of Loreto, río Blanco. B. Corydoras arcuatus unpreserved aquarium specimen. C. Corydoras granti unpreserved aquarium specimen from Peru, río Tapiche.

Photos A and C by Steven Grant, B by Hans-Georg Evers.

 

FIGURE 6. Live coloration of paratypes of Corydoras bethanae, BMNH 2017.5.25.1-21, showing A. female, and B. male. Fin coloration affected by background colors. Arrows indicate gap in arc-stripe around the suture between neurocranium.

Photos by Steven Grant.

FIGURE 8. Photos of the habitat of Corydoras bethanae, new species, showing A. its type-locality, the río Blanco, and B. the confluence of río Blanco (left) with río Tapiche, both in Peru.

Photo A by Mark Breeze, and B by Tom Christoffersen.

Rebecca Frances Bentley, Steven Grant and Luiz Fernando Caserta Tencatt. 2021. A New Arc-striped Species of Corydoras Lacépède, 1803 (Teleostei: Callichthyidae) from the Peruvian Amazon. Zootaxa. 4948(2); 184–200. DOI: 10.11646/zootaxa.4948.2.2  

Researchgate.net/publication/350186091_A_new_species_of_Corydoras_from_the_Peruvian_Amazon

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[Ichthyology • 2018] Corydoras benattii • From the Inside Out: A New Species of Armoured Catfish Corydoras (Siluriformes, Callichthyidae) with the Description of Poorly‐explored Character Sources

Corydoras benattii  Espindola, Tencatt, Pupo, Villa-Verde & Britto, 2018

 DOI: 10.1111/jfb.13602

Photo by  Hans Evers

Abstract  

A new species of the armoured catfish genus Corydoras is described from the Xingu–Tapajos ecoregion, Brazilian Amazon. The new species can be distinguished from its congeners by having the following combination of features: short mesethmoid, with anterior tip poorly developed, smaller than 50% of bone length; posterior margin of pectoral spine with serrations directed towards spine tip or perpendicularly oriented; infraorbital 2 only in contact with sphenotic; ventral laminar expansion of infraorbital 1 poorly or moderately developed; flank midline covered by small dark brown or black saddles with similar size to remaining markings on body; relatively larger, scarcer and more sparsely distributed dark brown or black spots on body; absence of stripe on flank midline; caudal fin with conspicuous dark brown or black spots along its entire surface; slender body; and strongly narrow frontals. A more comprehensive description of poorly‐explored internal character sources, such as the gross morphology of the brain, Weberian apparatus and swimbladder capsule elements is presented.

Keywords: Brazilian Amazon, Corydoradinae, Corydoras sp. C22, gross brain morphology, taxonomy, Xingu–Tapajos ecoregion

Figure 1: Corydoras benattii sp. nov. in (a) aquarium and (b) natural habitat, uncatalogued specimens, both near Altamira, lower Rio Xingu Basin. 

Figure 2: Corydoras benattii sp. nov., MZUSP 121671, holotype, 25·4 mm standard length, Brazil, Mato Grosso, Canarana–Gaúcha do Norte, Rio Culuene, tributary to Rio Xingu Basin.

Corydoras benattii, sp. nov.

Corydoras sp. 4. Castilhos & Buckup, 2011: 241 (species list).
Corydoras sp. C22. Evers, 1994: 755, Fig. 2 (species catalogue). Glaser et al., 1996: 92 (photos, species catalogue). Evers & Schäfer, 2004: 11, 12 (photos, species catalogue). Füller & Evers, 2005: 281, 285, 294 (species catalogue).
Corydoras sp. aff. C22. Glaser et al., 1996: 90 (photos, species catalogue).

Geographical distribution: Corydoras benattii occurs in both the Rio Xingu and Rio Tapajós basins, Brazilian Amazon (Fig. 10). In the Rio Xingu basin, it is known in Mato Grosso State from tributaries to the Rio Culuene, a clearwater tributary of the upper Rio Xingu (type locality) and in Pará State from the Rio Fresco sub drainage (Rio Trairão and Igarapé Manguari), middle Rio Xingu and from the lower Rio Xingu basin near Altamira. In the Rio Tapajós basin, it occurs in the Rio Peixoto de Azevedo, a tributary to the Rio Teles Pires, Mato Grosso and from Rio Cururu, a tributary to the Rio São Manuel, Pará.

Habitat notes: Specimens of Corydoras benattii were found in lotic habitats in the Rio Culuene, Rio Xingu basin and Rio Braço Norte, tributary to Rio Peixoto de Azevedo, Rio Tapajós basin (Fig. 11). Both localities have muddy‐brown water with clay and sandy substrata. Most specimens were captured in the small forest streams of black or clearwater, or in marginal ponds.

Etymology: The specific name, benattii, honours the late Laert Benatti for his humanitarian work, providing fresh water from artesian wells to poor communities in Brazil. Case is genitive.

V. C. Espíndola, L. F. C. Tencatt, F. M. Pupo, L. Villa‐Verde and M. R. Britto. 2018. From the Inside Out: A New Species of Armoured Catfish Corydoras with the Description of Poorly‐explored Character Sources (Teleostei, Siluriformes, Callichthyidae). Journal of Fish Biology.   DOI: 10.1111/jfb.13602

 Researchgate.net/publication/324606214_a_new_species_of_armoured_catfish_Corydoras

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[Ichthyology • 2017] Aspidoras mephisto • The First Troglobitic Callichthyidae (Teleostei: Siluriformes) from South America

Aspidoras mephisto  

Tencatt & Bichuette, 2017 

DOI: 10.1371/journal.pone.0171309 

Abstract

Aspidoras mephisto n. sp. is described from the Anésio-Russão cave system, upper Tocantins River basin, Goiás, Brazil. The species can be readily distinguished from its congeners by troglomorphic features and also by presenting the following combination of features: infraorbital 1 generally with well-developed ventral laminar; or moderately developed; poorly-developed serrations on posterior margin of pectoral spine; nuchal plate not externally visible; dorsal fin, even in conspicuously colored specimens, with only dark brown or black chromatophores concentrated on rays, forming spots in some specimens; membranes hyaline; or sparse dark brown or black chromatophores on membranes, not forming any conspicuous pattern; and inner laminar expansion of infraorbital 1 moderately developed. Information about its habitat, ecology, behaviour and conservation status are provided and also a brief description of the juvenile stage.

Aspidoras mephisto, new species

Fig 3. Aspidoras mephisto, holotype, MNRJ 48268, 45.6 mm SL, in dorsal (a), lateral (b) and ventral (c) views. 

Fig 9. Live uncatalogued specimen of Aspidoras mephisto from the Anésio III cave, Posse, Goiás, Brazil.

 Photograph: Danté Fenolio. DOI: 10.1371/journal.pone.0171309 

Fig 12. Foraging habitat observed for Aspidoras mephisto.
 (a), touching the bottom parallel to; (b), touching the silty-bottom + roots showing a 60° angle to; (c), starting to foraging under the small roots; and (d), foraging behavior under the roots (arrow).

Photographs: Maria E. Bichuette. DOI: 10.1371/journal.pone.0171309 

Fig 11. Map of the type-locality of Aspidoras mephisto, showing the Anésio-Russão cave-system, Posse, Goiás Brazil.

Author: Diego M. von Schimonsky. 

DOI: 10.1371/journal.pone.0171309 

Fig 2. Habitat of Aspidoras mephisto at Anésio III cave, Posse Goiás, Brazil,
showing (a), a small stretch of the drainage showing the roots reaching the water, lentic and formed by small roots and silt; (b), a pool with rocky in the border and silty-bottom, the black arrow indicates an adult specimen .

(Photographs: Maria E. Bichuette).   DOI:  10.1371/journal.pone.0171309

Geographical distribution: The new species is known only from the Anésio-Russão cave system (Anésio III and Russão II caves), part of the upper rio Tocantins basin (Fig 11).

Etymology: The epithet “mephisto” refers to the shortened name of Mephistopheles, demon from the German folklore. Mephistopheles comes from the Greek by the combination of three words: με (me), a negation, φῶς (phōs), meaning light, and φιλις (philis), meaning loving, literally “not-light-loving”, or the one who does not love the light, making allusion to the subterranean behavior of the new species. A noun in apposition.

Habitat, ecological and behavioral notes: Aspidoras mephisto shows preference to slow waters (small values of dissolved oxygen), small depths (ca. 0.05 m) and bottom formed by silt, clay and boulders, showing higher values of Total Dissolved Solutes compared to the epigean drainage. Its abundance is relatively high compared to other troglobitic fishes (ca. 50 individuals in pools), and population densities of 5–6 inds.m-2. Juvenile individuals were observed along small stretches of the drainage, always in lentic and shallow places, isolated from the adults and frequently under roots (Fig 2C).

Aspidoras mephisto forages calmly close to small submersed roots and silty-bottom (Fig 12A and 12B). They use the anterior extremity of the snout exploring the substrate in a parallel position or forming an angle of ca. 60° in relation to the bottom (Fig 12B), sometimes under the small roots (Fig 12C and 12D). The fish showed this behavior throughout the entire observation time (ca. 20 min) and did not show escape and/or avoidance behavior due to lamp-light or other external disturbances (such as the presence of the observer).

Luiz Fernando Caserta Tencatt and Maria Elina Bichuette. 2017. Aspidoras mephisto, New Species: The First Troglobitic Callichthyidae (Teleostei: Siluriformes) from South America. PLoS ONE. 12(3): e0171309. DOI: 10.1371/journal.pone.0171309

  

[Ichthyology • 2016] Corydoras hephaestus • Wrapped in Flames: A New Remarkably Colored Species (Teleostei: Callichthyidae) from the Rio Madeira basin, Rondônia State, Brazil

Corydoras hephaestus 

Ohara, Tencatt & Britto, 2016

 DOI: 10.11646/zootaxa.4170.3.7  

Abstract

A new species of Corydoras is described from the upper Rio Machado, Rio Madeira basin, Rondônia State, Brazil. The new species can be distinguished from its congeners by the absence of contact between the posterior process of the parieto-supraoccipital and the nuchal plate; a ventral laminar expansion of the infraorbital 1 conspicuously developed; and the posterior margin of the pectoral-fin spine with serrations along almost of its entire length, only lacking in the distal portion. Additionally, Corydoras hephaestus possesses dorsal and pectoral spines short, and exhibits an unusual color pattern in life. The conservation status of the new species and other endemic species are briefly commented.

Keywords: Pisces, Amazon, Corydoradinae, Fish, Endemism, Conservation

Etymology. The specific epithet hephaestus is from the Greek, Ἥφαιστος (or Hēphaistos), the Greek god of fire, metalworking, forges, and blacksmiths. Alluding to the red color of the body and fins. A noun in apposition.

Ohara, Willian M., Luiz F. C. Tencatt & Marcelo R. Britto. 2016. Wrapped in Flames: Corydoras hephaestus, A New Remarkably Colored Species from the Rio Madeira basin (Teleostei: Callichthyidae). Zootaxa. 4170(3): 539–552. DOI: 10.11646/zootaxa.4170.3.7

 ResearchGate.net/publication/308626103_Wrapped_in_flames_Corydoras_hephaestus_a_new_remarkably_colored_species_from_the_Rio_Madeira_basin_Teleostei_Callichthyidae