[Ichthyology • 2026] Opsarius geminus • A New danionid fish (Cypriniformes: Danionidae) from the Western Ghats, India and Revalidation of Barilius papillatus Day 1869

 

 Opsarius geminus

Vijayakrishnan, Nallathambi, Jayasimhan, & Knight, 2026

Barilius papillatus Day 1869

DOI: doi.org/10.11646/zootaxa.5878.4.7

Abstract

Opsarius geminus, a new species of danionid fish is described from the Krishna River, Western Ghats, India. It can be distinguished from its congeners in the Western Ghats by possessing a combination of the following characters: unique colour pattern consisting of 9–11 blue bars that are 2–3 scales wide; 46–51 lateral-line scales; 20–23 pre-dorsal scales; barbels absent; length of last dorsal-fin ray almost equal to, or greater than length of first dorsal-fin ray; 7 ½–8½ dorsal-fin branched rays and 10½–11½ anal-fin branched rays. Barilius papillatus Day 1869, currently a synonym of Opsarius barna (Hamilton, 1822) is redescribed, based on the syntype and fresh specimens, and a lectotype is designated to fix its identity. Opsarius papillatus can be diagnosed from all its congeners in India, by possessing a combination of the following characters: colour pattern consisting of 7–9 blue bars that are 1–2 scales wide; 39–41 lateral-line scales; 15–18 pre-dorsal scales; barbels absent; length of last dorsal-fin ray shorter than length of first dorsal-fin ray; 7½ dorsal-fin branched rays and 10½ anal-fin branched rays.

Pisces, new species, Opsarius barna, Krishna River, Mahanadi River, Eastern ghats

 

 

BALAJI VIJAYAKRISHNAN, MOULITHARAN NALLATHAMBI, PRAVEENRAJ JAYASIMHAN, J.D. MARCUS KNIGHT. 2026. Opsarius geminus, A New danionid fish from the Western Ghats, India and Revalidation of Barilius papillatus Day 1869 (Teleostei: Danionidae).  Zootaxa. 5878(4); 589-600. DOI: doi.org/10.11646/zootaxa.5878.4.7 [2026-09-16]

  facebook.com/praveenraj.39750121/posts/28655245830753728

[Ichthyology • 2026] Chromis veneta • Resolving Cryptic Diversity in the Chromis viridis species complex (Blenniiformes: Pomacentridae): a multilocus phylogenetic and morphometric reassessment of species boundaries

 

Chromis veneta 

Rekha, Jayakumar, Abhilash, Ahamed Rasheeq, Saikrishnan, Vallarasu, Gladston, Chakraborty & Ajithkumar, 2026

  

DOI: doi.org/10.3389/fmars.2026.1922804

Abstract

The blue-green damselfish, Chromis viridis (Cuvier, 1830), is widely distributed across Indo-Pacific coral reefs and is among the most heavily traded marine ornamental fishes. Recent molecular studies have suggested the presence of cryptic diversity within the C. viridis complex, but species boundaries remain unresolved. Multilocus phylogenetic analyses incorporating three mitochondrial markers—cytochrome c oxidase subunit I (COI), cytochrome b (cytb), and the mitochondrial control region (D-loop)—and two nuclear markers, recombination-activating gene 1 (RAG1) and recombination-activating gene 2 (RAG2), were performed to assess lineage diversification within the Chromis viridis species complex. Specimens collected from the Lakshadweep Archipelago and the Gulf of Mannar, India, formed a distinct and well-supported lineage that was clearly separated from C. viridis sensu stricto and other congeners in phylogenetic reconstructions and genetic distance analyses. Multiple species-delimitation approaches consistently supported the recognition of this lineage as an independently evolving taxon, and morphometric analyses revealed corresponding differences in body proportions and meristic characters. Based on the concordance of molecular and morphological evidence, a new species, Chromis veneta sp. nov., is herein described from the Indian Ocean. The new species differs from C. viridis in having a relatively elongate body, narrower caudal peduncle, distinctive body pigmentation, yellowish to orangish distal fin margins, and a deeply forked caudal fin with elongate lobe tips. Additional diagnostic features include differences in dentition, gill-raker counts and sagittal otolith morphology. The discovery of C. veneta sp. nov. highlights underestimated diversity within the C. viridis complex and underscores the importance of integrative taxonomy in revealing cryptic reef-fish diversity.

Keywords: Chromis veneta sp. nov., Chromis viridis complex, cryptic species diversity, species delimitation, multilocus phylogenetics, integrative taxonomy, morphometric analysis, Pomacentridae

 

Chromis veneta sp. nov., freshly collected holotype, NBFGR/POMCVEN, 52.0 mm SL, Agatti Island.

Caption Male of Chromis veneta sp. nov. (64.51 mm SL) in live breeding coloration.

Chromis veneta sp. nov. in its natural coral reef habitat at Agatti Island, Lakshadweep, associated with branching Acropora corals and occurring sympatrically with Chromis viridis, Pomacentrus pavo, and Dascyllus aruanus.

Chromis veneta sp. nov.

 Diagnosis: Chromis veneta sp. nov. is distinguished from its congeners by the following combination of characters: dorsal-fin rays XII, 9–10 (usually 10); anal-fin rays II, 9–10 (usually 10); pectoral-fin rays 16–17 (usually 17); pelvic-fin rays I, 5; principal caudal-fin rays 8 + 7; spiniform caudal rays 3; tubed lateral-line scales 15–16; gill rakers 9–10 + 23–26 (usually 9 + 24), total 33–35 (usually 33); body depth 2.27–2.56 in SL; caudal-peduncle depth 0.63–0.77 in head length; and caudal-peduncle length 0.51–0.73 in head length. In life, the body is bright aquamarine-green with a subtle iridescent blue-green sheen. Each scale on the upper and middle flanks is narrowly edged with yellow-green, forming a fine reticulate pattern that becomes more conspicuous under illumination. The ventral surface is pale silvery white. A diffuse black patch is present at the upper base of the pectoral fin and is more conspicuous in live specimens. A fine, continuous blue-green stripe extends from the tip of the snout to the anterior margin of the orbit. Reproductively active individuals further exhibit distinct yellowish to amber pigmentation along the distal margins of the dorsal and anal fins.

Etymology: The specific epithet, veneta is derived from the Latin venetus, meaning “sea-blue” or “azure,” referring to the characteristic of blue green to turquoise coloration exhibited by the species in live condition. The name is treated as an adjective in agreement with the generic name Chromis.

 

M. U. Rekha, Teena Jayakumar T. K., Abhilash C. P. Ahamed Rasheeq A., Saikrishnan K. R., Vallarasu R., Gladston Y., Kajal Chakraborty and Ajithkumar T. T. 2026. Resolving Cryptic Diversity in the Chromis viridis species complex (Pomacentridae): a multilocus phylogenetic and morphometric reassessment of species boundaries. Front. Mar. Sci. 13; 1922804. DOI: doi.org/10.3389/fmars.2026.1922804 [04 September 2026]

[Ichthyology • 2026] Petulanos jasteri • A New Species of Petulanos (Characiformes: Anostomidae) from the Rio Araguari, Amapá State, Brazil

 

Petulanos jasteri

Birindelli, Lima & Gama, 2026

 DOI: doi.org/10.1643/i2025080

Abstract

The Neotropical family Anostomidae comprises over 150 valid species, though its true diversity remains underestimated. The genus Petulanos currently includes four species distributed across northern South America, all characterized by upturned mouths, compressed multicuspid dentition, and distinctive color patterns. In this study, we describe Petulanos jasteri, a new species apparently endemic to the rio Araguari, Amapá state, Brazil. Despite hosting extensive protected areas, Amapá remains poorly surveyed, and its ichthyofauna is still insufficiently documented. The new species is readily distinguished from congeners by its color pattern, consisting of three vertically elongated dark blotches on the posterior half of the trunk (without pale margins) combined with eight to ten dark vertical bars. It lacks the horizontal stripes that characterize P. brevior, as well as the rounded blotch above the pectoral fin present in P. intermedius, P. plicatus, and P. spiloclistron, and has 38 or 39 lateral-line scales (vs. 40 to 42 in P. spiloclistron). Osteological characters confirm its assignment to Petulanos, sharing synapomorphies such as four branchiostegal rays, bicuspid symphyseal premaxillary tooth, symplectic with a distinctive triangular ventral lamina, and open cranial fontanel. Petulanos jasteri, new species, is the first species of the genus reported from the rio Araguari. Its discovery emphasizes the underestimated diversity of the Anostomidae and highlights the need for further surveys and integrative studies in poorly explored basins of northern Brazil.

Petulanos jasteri.
(A) Holotype, IEPA 6078, 72.9 mm SL, Amapá, Ferreira Gomes, rio Mutum, tributary to rio Araguari, at Parque Nacional Montanhas do Tumucumaque.
(B) Paratype, ZUEC 14774, 83.7 mm SL, Amapá, Ferreira Gomes, rio Araguari.
(C) Paratype, ANSP 211099 (ex. IEPA 6079), 64.1 mm SL, rio Mutum, tributary to rio Araguari, at Parque Nacional Montanhas do Tumucumaque, photographed alive.

Scale bar = 10 mm. 

Petulanos jasteri, a new species 

Etymology.—The specific name jasteri honors Dr. Christoph Bernhard Jaster, formerly chief of the Tumucumaque National Park and the Amapá National Forest, for having made possible many field expeditions in these Conservation Units for the IEPA Ichthyology team, being a great supporter of basic science and biological surveys at Amapá State.

José L. O. Birindelli, Flávio C. T. Lima, Cecile S. Gama. 2026. New Species of Petulanos (Characiformes, Anostomidae) from the Rio Araguari, Amapá State, Brazil. Ichthyology & Herpetology. 114(3):451-460. DOI: doi.org/10.1643/i2025080 [28 August 2026]

[Ichthyology • 2026] Glyptothorax jiwanae • A New Species of the Sisorid Catfish Genus Glyptothorax (Siluriformes: Sisoridae) from Nepal

 

 Glyptothorax jiwanae

Haggard, Ng, Edds & Conway, 2026

DOI: doi.org/10.1643/i2025050  

 x.com/IchsAndHerps

Abstract

Glyptothorax jiwanae, new species, is described in this study based on 42 specimens, 41–133 mm SL, from Nepal. It is distinguished from congeners by a combination of characters, including presence of longitudinal striae on the gular region, presence of adhesive papillae on the lower lip, premaxillary teeth hidden when the mouth is closed, nasal barbel reaching posterior to eye, skin flaps along the posterior edges of the maxillary and inner and outer mandibular barbels extending for half or less of barbel length, round eye, thoracic adhesive apparatus (TAA) consisting only of longitudinally oriented striae, an elongate, oval depression within the medial pit of the TAA, finely tuberculate skin, pelvic origin at a vertical through or slightly anterior to the base of the last dorsal-fin ray, length of adipose-fin base 14.9–18.4% SL, i,7,8,i caudal-fin rays, caudal-fin lobes approximately equal in length, and slightly asymmetrical procurrent rays.

 Glyptothorax jiwanae, KU 28638, holotype, 55.4 mm SL, Nepal, Rautahat/Sarlahi, Bagmati River. Scale bar = 5 mm.

Glyptothorax jiwanae, new species 

Etymology.— This species is named after Dr. Jiwan Shrestha, for her pioneering work on elucidating the ichthyofaunal diversity of Nepal. A noun in the genitive.

 

Angela Haggard, Heok Hee Ng, David R. Edds and Kevin W. Conway. 2026. A New Species of the Sisorid Catfish Genus Glyptothorax from Nepal (Siluriformes: Sisoridae). Ichthyology & Herpetology. 114(3):439-450. DOI: doi.org/10.1643/i2025050 [20 August 2026]

 x.com/IchsAndHerps/status/2091934920453062812

[Ichthyology • 2026] Laimosemion laranja • A New killifish of the Genus Laimosemion (Cyprinodontiformes: Rivulidae) from Rio Cajari in the Brazilian Amazon

Laimosemion laranja 

Abrantes, Lima, Nielsen, de Lira, da Silva & Berbel-Filho, 2026

 

DOI: doi.org/10.3897/zse.102.187659

Abstract

Based on morphological and molecular evidence, this study describes a new species of rivulid of the genus Laimosemion from the lower Rio Amazonas Basin in the south of the state of Amapá in northern Brazil. The new species, Laimosemion laranja sp. nov., exhibits a color pattern characteristic of the L. geayi species group, consisting of longitudinal rows of spots on the anterior portion of flank and oblique chevron-shaped bars on the posterior portion of flank. It can be distinguished from its congeners by unique combination of characters, including position of dorsal-fin origin relative to anal-fin rays, frontal squamation pattern of head, counts of transverse and longitudinal scale series, fin-ray counts, vertebral count, osteology of caudal fin, and number of neuromasts in infraorbital series. Partial sequences of the mitochondrial cytochrome c oxidase subunit I (cox1) gene indicates that the new species diverges genetically by 5.3% from its closest relatives, L. agilae and L. strigatus, by 9.2% from L. dibaphus, and 12.3% from L. geayi. We further discuss the systematic relationships within the L. geayi species group and the conservation status of the new species based on IUCN criteria, including recommendations for its conservation.

Key Words: Amapá State, Amazonas Estuary and Coastal Drainages Ecoregion, Amazonian ichthyofauna, conservation

Laimosemion laranja new species
 Holotype [INPA–ICT 062600], male, 26.8 mm SL; 
 Paratype [INPA–ICT 062601], female, 20.1 mm SL 
Brazil, Amapá, Laranjal do Jari, Rio Cajari, Amazonas Basin.

photos: Y. Abrantes. 

 

Laimosemion laranja sp. nov.

Diagnosis. Laimosemion laranja differs from the six congeners of the L. geayi group by having eight scales in transverse series (vs.7 in L. dibaphus and L. strigatus, 9 in L. geayi, 9–10 in L. agilae and L. cladophorus, and 9–11 in L. mabura). It can be distinguished from all other congeners of the L. geayi group, except L. agilae and L. cladophorus, by dorsal-fin origin positioned on transversal plane through bases of 4th–6th anal-fin rays in both sexes (vs. of 7th–8th anal-fin rays). It differs from L. agilae by frontal squamation pattern of head (E squamation vs. F squamation) and from ...

Etymology. The specific epithet ‘laranja’ is a name with a dual allusion. It refers to the bright orange color pattern on males of the new species (‘laranja’ means the color, as it also means the fruit in Portuguese), and is also an homage to the municipality of Laranjal do Jari, founded on December 17, 1987, in the south of Amapá State, Brazil, from where the species is currently only found. A noun in apposition.

Sampling localities of Laimosemion laranja new species.
 Localities one and two (A, B), and the type locality (C). Brazil, Amapá, Laranjal do Jari, Rio Cajari, Amazonas Basin.

 Photos: W.M. Berbel-Filho.

Yuri Gomes Abrantes, Sergio Maia Queiroz Lima, Dalton Tavares Bressane Nielsen, Fabio Origuela de Lira, Márcio Joaquim da Silva, Waldir Miron Berbel-Filho. 2026. A New killifish of the Genus Laimosemion (Cyprinodontiformes, Rivulidae) from Rio Cajari in the Brazilian Amazon. Zoosystematics and Evolution. 102(4): 1079-1088. DOI: doi.org/10.3897/zse.102.187659 [20 Aug 2026]

[Ichthyology • 2026] Rakthamichthys anchi • A New Species of phreatobitic synbranchid eel (Synbranchiformes: Synbranchidae) from Assam, India

 

Rakthamichthys anchi 

Britz, Pinion, Marak, Velentina & Lokeshwor, 2026 

 

DOI: doi.org/10.11646/zootaxa.5857.3.3

Abstract

Rakthamichthys anchi, a new species of phreatobitic synbranchid is described from wells in a small village in Goalpara District, Assam, Northeast India. It is distinguished from the northeastern Indian R. rongsaw, and the Western Ghats congeners R. roseni, R. digressus, and R. mumba by absence of lateral-line canal pores in the frontal. From R. roseni, R. digressus, and R. mumba, it is further distinguished by more preanal vertebrae (90–100 vs. 76–88 in) and from R. indicus by more vertebrae (159 vs.162–169). It is also distinguished from the Western Ghats species by an uncorrected p-distance of ~15–20% in the barcoding gene. From R. roseni, the only Western Ghats species for which detailed osteological information is available, R. anchi is distinguished by several anatomical characters. The discovery of R. anchi from wells in the same village in which Gitchak nakana Britz et al. [2026] was recently described highlights the presence of a formerly unknown and highly dynamic subterranean habitat: the groundwater aquifers in alluvial deposits in northeast India.

Pisces, swamp eels, groundwater, well, subterranean fishes, micro-CT, skeleton

Ralf BRITZ, Amanda K. PINION, Wimarithy K. MARAK, Kangjam VELENTINA and Yumnam LOKESHWOR. 2026. Rakthamichthys anchi, A New Species of phreatobitic synbranchid eel from Assam.  Zootaxa. 5857(3); 462-482. DOI: doi.org/10.11646/zootaxa.5857.3.3 [2026-07-30]

[Ichthyology • 2026] Hippocampus amandavincentae • A New Species of Spiny Seahorse (Syngnathiformes: Syngnathidae) from Indian Ocean, with Redescription of H. histrix and H. jayakari

 

Hippocampus amandavincentae  

Shalu, Short, Raghavan, Ramvilas & Ranjeet, 2026

DOI: doi.org/10.11646/zootaxa.5862.2.4  

 facebook.com/RajeevRAGHAVAN98

 

Abstract

The thorny seahorse, Hippocampus histrix Kaup, 1856, has long been treated as a single, widely distributed species ranging from the Red Sea and western Indian Ocean to the western Pacific. Morphological and molecular evidence now demonstrate that this broad concept encompasses at least three diagnosable species. Examination of Indian Ocean specimens combined with mitochondrial COI sequence analysis reveals a new lineage herein described as Hippocampus amandavincentae sp. nov., based on material from southeastern India and corroborated by published sequences from Madagascar, Mozambique, the Seychelles, and the northern Red Sea. The new species is diagnosed by a shorter snout, five coronet spines, and spines present on all principal trunk and tail ridges. A published COI sequence from the northern Red Sea places H. amandavincentae in apparent sympatry with Hippocampus jayakari Boulenger, 1900, in that region, indicating that the distributional boundary between these two species requires targeted field investigation. Hippocampus histrix sensu stricto is redescribed and its distribution restricted to the Pacific Ocean, including Japan, Indonesia, and the Philippines, based on direct examination of type material. Hippocampus jayakari, described from the Gulf of Oman, is confirmed as a distinct species of the northwestern Indian Ocean, readily distinguished by four cleithral spines with the ventral-most bifurcate, a shorter and deeper snout, and spines confined to alternating tail rings. Together, these three species represent geographically coherent lineages whose delineation resolves over a century of misidentification in museum collections and online databases, stabilises the application of long-used names, and provides a practical framework for regional conservation assessment and future systematic research on spiny seahorses across the Indo-Pacific.

Pisces, barcoding, India, species complex, taxonomy, thorny seahorse

Hippocampus amandavincentae sp. nov.

Hippocampus amandavincentae sp. nov.

Kannan SHALU, Graham SHORT, Rajeev RAGHAVAN, Ghosh RAMVILAS and Kutty RANJEET. 2026. A New Species of Spiny Seahorse, Hippocampus amandavincentae, with Redescription of H. histrix and H. jayakari (Teleostei: Syngnathidae).  Zootaxa. 5862(2); 271-292. DOI: doi.org/10.11646/zootaxa.5862.2.4 [2026-08-05] 

  facebook.com/RajeevRAGHAVAN98/posts/10162487911550938

[Ichthyology • 2026] Nanosphronemus gemma • A remarkable New Genus and Species of miniature osphronemid (Anabantoidei: Osphronemidae) from Vietnam

Nanosphronemus gemma

 Britz, Tan & Rüber, 2026

Raffles. Bull. Zool. 74; 

Abstract

 A new genus and species of miniature labyrinth fish of the family Osphronemidae, Nanosphronemus gemma, is described from Vietnam. It differs from all other genera of anabantoids by a unique dorsal- and anal-fin ray count, a unique colour pattern and a number of unique or highly unusual skeletal characters. Our molecular phylogenetic analysis indicates that Nanosphronemus is the sister group of the genus Trichopsis, the croaking gouramis. 

Key words. Anabantoidei, labyrinth fishes, miniaturisation, gourami

Nanosphronemus gemma, live colouration, not preserved, all ca. 16 mm SL in lateral view.
a, putative female above, note absence of red stripe in dorsal half; b, putative male in normal colouration, note presence of red stripe above and darker pigmentation below midlateral stripe; c, putative male in breeding colouration, note overall darker colouration of body and also fins, presence of bright red stripe and highly iridescent scales in mid-lateral stripe and below on head and body.

Nanosphronemus gemma, not preserved, all ca. 18 mm SL.
a, mature female with eggs; b, in breeding colouration and typical oblique courtship position, c, approaching bubble nest under plant leaf; d, adding air bubbles and embedding eggs into bubble nest.

Nanosphronemus, new genus  

Diagnosis. Nanosphronemus differs from all other genera in the suborder Anabantoidei by its unique count of XIX– XXI+2–3 dorsal-fin rays (vs. I–XVIII+ 4–14, rarely XIX in some specimens of Macropodus ocellatus) and XX– XXIV+4–5 anal-fin rays (vs. I–XVII+8–38, rarely XX–XXII in some specimens of Macropodus spp.), the presence (vs. absence) of a series of anteroventrally directed processes off the distal part of caudal haemal arches, Baudelot’s ligament ...

Etymology. The new genus name is derived from the Ancient Greek word, νάνος, meaning dwarf, combined with the name Osphronemus, the type genus of the family Osphronemidae, to which this new genus belongs. Gender: masculine. The name alludes to the tiny size of this new fish, which makes it one of the smallest anabantoids known to date.

Nanosphronemus gemma, new species 

 Suggested common name. Jewel Gourami.

Distribution. Unclear at present: reported from undisclosed area near Huế in Central Vietnam. 

Etymology. The species name is derived from the Latin word for jewel, ‘gemma’, alluding to the stunning colouration of sexually mature males. A noun in apposition.

 

Ralf BRITZ, Heok Hui TAN and Lukas RÜBER. 2026. Nanosphronemus gemma, A remarkable New Genus and Species of miniature osphronemid from Vietnam (Teleostei: Anabantoidei: Osphronemidae). Raffles. Bull. Zool. 74; 606–623. 

 

[Ichthyology • 2026] Molecular Phylogenetics and A New Taxonomy of the Neotropical Electric Fishes (Actinopterygii: Otophysi: Gymnotiformes)

 

Representatives of the six gymnotiform families Apteronotidae (A), Sternopygidae (S), Gymnotidae (G), Electrophoridae (E), Hypopomidae (H), and Rhamphichthyidae (R). 

Top to bottom, and left to right, are: Rhamphichthys rostratus (R), Archolaemus janeae (S), Sternarchorhamphus muelleri (A), Eigenmannia magoi (S), Gymnotus carapo (G), Sternarchorhynchus sp. (A), Apteronotus galvisi (A), Orthosternarchus tamandua (A), “Apteronotus” (Genus B) cuchillejo (A), Apteronotus eschmeyeri (A), Apteronotus cf. albifrons (A), Gymnorhamphichthys sp. (R), Sternarchorhynchus marreroi (A), Sternopygus aequilabiatus (S), Adontosternarchus devenanzii (A), Steatogenys duidae (R), Brachyhypopomus occidentalis (H), Hypopomus artedi (H), and Electrophorus multivalvulus (E). 

in Janzen, Sabaj, Crampton et Lovejoy, 2026.

DOI: doi.org/10.1016/j.ympev.2026.108678 

Photos by M. Sabaj.

  

Highlights: 

• New 9 gene molecular tree for 202 species of Neotropical electric knifefishes (order Gymnotiformes)

• A new taxonomy is proposed, based on the most extensive phylogenetic analysis to date.

• Strong phylogenetic support for 6 families, including the Electrophoridae (electric eels)

• Two main groups of species defined by either pulse or wave-type electric signals.

• Two new suborders: Pulseoidei for pulse-type species and Sinusoidei for wave-type species.

Abstract

The order Gymnotiformes—Neotropical electric eels and knifefishes—comprise a distinctive lineage of freshwater fishes characterized by electrogenesis and electroreception. Despite their ecological, evolutionary, and neurobiological significance, phylogenetic relationships within the order remain incompletely resolved. We present the most taxonomically inclusive molecular phylogeny of Gymnotiformes to date, based on two mitochondrial and seven nuclear genes from 202 species representing 31 of 36 extant genera. Maximum likelihood and Bayesian inference analyses provide strong support for a concordant species-level phylogenetic arrangement that we use to propose a revised classification of Gymnotiformes, including new suprageneric names and reassignments of some taxa and species. We found support for six monophyletic families, including Electrophoridae (electric eels). We propose two new suborders corresponding to electric signal type: Pulseoidei (pulse-type) and Sinusoidei (wave-type), an arrangement that does not allow determination of whether a pulse or wave-type signal was ancestral. In Apteronotidae, the subfamilies Sternarchorhamphinae and Apteronotinae are supported; within Apteronotinae, we establish the tribe Steatogenini to include Porotergus, Sternarchella, and close relatives. We resolve the non-monophyly of Apteronotus with generic reassignments. For Sternopygidae, we support the monophyletic subfamilies Sternopyginae and Eigenmanniinae and resolve polyphyly in Rhabdolichops and Eigenmannia via generic reassignments. Within Gymnotus, we support six species groups. We confirm the sister-group relationship between Hypopomidae and Rhamphichthyidae and clarify their internal structure, including support for six species groups within the diverse genus Brachyhypopomus. Our study provides a robust phylogenetic framework for Gymnotiformes and establishes a foundation for future work on systematics, biogeography, trait evolution, and comparative neurobiology.

 

Keywords: Neotropical, Systematics, Electric eel, Knifefish, Electric organ discharges

Sinusoidei subord. nov. changed from “Sinusoidea” of Albert 2001

Pulseoidei subord. nov. changed from “Pulseoidea” of Alda et al. 2018

Representatives of the six gymnotiform families Apteronotidae (A), Sternopygidae (S), Gymnotidae (G), Electrophoridae (E), Hypopomidae (H), and Rhamphichthyidae (R). 

Top to bottom, and left to right, are: Rhamphichthys rostratus (R), Archolaemus janeae (S), Sternarchorhamphus muelleri (A), Eigenmannia magoi (S), Gymnotus carapo (G), Sternarchorhynchus sp. (A), Apteronotus galvisi (A), Orthosternarchus tamandua (A), “Apteronotus” (Genus B) cuchillejo (A), Apteronotus eschmeyeri (A), Apteronotus cf. albifrons (A), Gymnorhamphichthys sp. (R), Sternarchorhynchus marreroi (A), Sternopygus aequilabiatus (S), Adontosternarchus devenanzii (A), Steatogenys duidae (R), Brachyhypopomus occidentalis (H), Hypopomus artedi (H), and Electrophorus multivalvulus (E). 

Photos by M. Sabaj.

  

 

 Francesco H. Janzen, Mark H. Sabaj, William G.R. Crampton, Nathan R. Lovejoy, 2026. Molecular Phylogenetics and A New Taxonomy of the Neotropical Electric Fishes (Actinopterygii: Otophysi: Gymnotiformes). Molecular Phylogenetics and Evolution. In Press, 108678. DOI: doi.org/10.1016/j.ympev.2026.108678 [10 July 2026]

[Ichthyology • 2026] Acrossocheilus zhangjiajiensis • Integrative Taxonomy reveals A New Species of Acrossocheilus (Cypriniformes: Cyprinidae) from Hunan Province, China

Acrossocheilus zhangjiajiensis

in Cao, Deng, Xiang, Xie, Wang, Li, Hu, Wei et Jiang, 2026.

张家界光唇鱼  ||  DOI: doi.org/10.3897/zse.102.195486

Abstract

The genus Acrossocheilus (Cyprinidae), which occurs in Southeast Asia and southern China, is of significant ecological and economic importance. A new species, Acrossocheilus zhangjiajiensis sp. nov., is described from the upper Lishui River Basin, a tributary of the Yangtze River, in Sangzhi County, Zhangjiajie City, Hunan Province, China. The description is based on an integrative taxonomic approach combining morphological examination, DNA barcoding, and mitogenomic analyses. This new species is distinguished from all congeners by the following combination of characters: a maxillary barbel extending to the midline of the eye; a slightly hardened last unbranched dorsal-fin ray with a smooth posterior margin; dorsal-fin membranes with black stripes; the second primary vertical bar (PVB2) positioned anterior to the origin of the dorsal fin; juveniles and adults possessing six distinct vertical black bars on the flank; and fewer than 40 lateral line scales. Notably, it further differs from its sister species, A. jishouensis, in several morphometric traits, as well as the texture of the last unbranched dorsal-fin ray and the persistence of vertical flank bars throughout all life stages. The complete mitogenome of A. zhangjiajiensis sp. nov. is 16,592 bp in length. Phylogenetic analyses based on the mitochondrial COI gene and the 13 protein-coding genes (PCGs) support a sister-species relationship between A. zhangjiajiensis sp. nov. and A. jishouensis, with genetic distances of 3.1%​ (COI) and 3.3% (13 PCGs). A COI-based haplotype network and species delimitation analyses further support the distinctiveness of the new species. This discovery increases the total number of valid Acrossocheilus species to 25 and provides critical data for the systematics, evolution, and conservation of this genus.

Key Words: Cyprinid, integrative taxonomy, morphology, mitogenome, Yangtze River

Live specimens of Acrossocheilus zhangjiajiensis sp. nov.
A. Lateral view of body; B. Lateral view of head; C. Ventral view of head; D. Dorsal view of head.

 

Acrossocheilus zhangjiajiensis sp. nov.

Etymology. The specific epithet zhangjiajiensis is derived from Zhangjiajie City, where the type locality of this species is located. Currently, this taxon is known only from this type locality, and its Chinese name is “Zhāng jiā jiè guāng chún yú (张家界光唇鱼)”.

 Jianhan Cao, Zhiyong Deng, Hongmei Xiang, Yixing Xie, Cheng Wang, Hong Li, Yang Hu, Ying Wei and Wansheng Jiang. 2026. Integrative Taxonomy reveals A New Species of Acrossocheilus (Cypriniformes, Cyprinidae) from Hunan Province, China. Zoosystematics and Evolution. 102(3): 869-883. DOI: doi.org/10.3897/zse.102.195486 [25-06-2026]

[Ichthyology • 2026] The prolonged Reemergence of Megapredatory Pelagic Fishes

  

the diversification of living large-bodied (> 2 m) marine predatory fishes such as tunas and mackerels (Scombridae)

in Brownstein, Alencar, Kindsvater, Thacker, Wainwright, Near et Harrington, 2026. 

DOI: doi.org/10.1098/rspb.2026.1257 

 x.com/ChaseBrownstein

 

Abstract

The assembly of modern ocean ecosystems was fundamentally affected by the Cretaceous–Palaeogene (K-Pg) mass extinction. Among the casualties of this event were many extinct clades of large pelagic predatory fishes. The extinction of these lineages is thought to have created ecological opportunity that spurred the diversification of living large-bodied (> 2 m) marine predatory fishes such as tunas and mackerels (Scombridae). However, it remains unclear whether a large, endothermic body plan evolved in tunas and mackerels directly after the K-Pg boundary or in a stepwise manner throughout the Cenozoic. Here, we demonstrate that Scombridae, which includes half of living endothermic ray-finned fish species, evolved endothermy and large body sizes long after the initial radiation of the clade at the K-Pg boundary. Our time-calibrated phylogeny also reveals that the origins of endothermy, large body size and increased longevity in true tunas are staggered over evolutionary time. These findings indicate that the evolution of large endothermic scombrids was not triggered by the K-Pg extinction and substantiate the protracted development of the endothermic predatory body plans of tunas and relatives over more than 50 million years of evolutionary history.

Keywords: Scombridae, tunas, phylogenomics, K-Pg mass extinction, endothermy

Origin of large body sizes in Scombridae. The phylogeny is coloured according to the ancestral state reconstruction for log-transformed standard length. Warmer colours indicate body sizes approaching 4 m. Body size increases over 2 m are denoted by Roman numerals. The innermost dashed circle indicates the K-Pg boundary. Illustrations of scombrids are by Julie Johnson (lifesciencestudios.com).

Tempo of trait shifts in Scombridae. Inferred histories of significant trait optima shifts across Scombridae plotted on the time-calibrated phylogeny of this clade. Shifts inferred with over 30% posterior probability are included. The full bayou outputs are in the electronic supplementary material associated with this article. Illustrations of scombrids are by Julie Johnson (lifesciencestudios.com).

Chase D. Brownstein; Laura R. V. Alencar; Holly K. Kindsvater; Christine E. Thacker; Dylan K. Wainwright; Thomas J. Near and Richard C. Harrington. 2026. The prolonged Reemergence of Megapredatory Pelagic Fishes.  Proc Biol Sci. 293 (2074): 20261257. DOI: doi.org/10.1098/rspb.2026.1257 [08 Jul 2026] 

 x.com/ChaseBrownstein/status/2074791152318865890

[Ichthyology • 2026] Brachygobius jennie • A New bumblebee goby (Gobiiformes: Oxudercidae) from Hengqin Island, Guangdong Province, China

Brachygobius jennie  

 Tian, Wu, Lan, Lavoué & Huang, 2026. 

 DOI: doi.org/10.3897/zse.102.184142

Abstract

A new species of bumblebee goby, Brachygobius jennie sp. nov. (Teleostei, Oxudercidae), is described based on 31 specimens collected from the Hengqin Island, Guangdong Province, China. This new species is distinguished from all other valid species of Brachygobius by its extreme small size (SL < 9 mm) and distinctive number, position, size and shape of its black bars. It possesses four complete (forming ring) or nearly complete post-cephalic, relatively narrow bars, two of which are located posterior to the base of the anal fin. The first bar behind the head extends pigmentation to the first dorsal fin but does not reach the midventral line. The second bar, chevron-shaped and located below the second dorsal fin, extends pigmentation onto that fin and ventrally reaches the midventral line and the anal fin. Cytochrome oxidase subunit I-based analyses, including six out of the eight valid species of Brachygobius, show Brachygobius jennie sp. nov. to be more than 10% genetically divergent from other species, supporting the morphological diagnosis and confirming its distinct taxonomic status. With a maximum size of less than 9 mm SL (based on observations of 106 specimens), the new species is not only the smallest species of Brachygobius, but also one of the smallest known gobioid fishes.

Key Words: Fish, Gobioidei, integrative taxonomy, new species, miniature vertebrates

Diagnostic marking pattern comparison among all species of Brachygobius having four post-cephalic black bands, the last two located posterior to the base of the anal fin. Left column: schematic drawings highlighting diagnostic marking patterns based on information from type material and original descriptions; from top to bottom: 
Brachygobius jennie sp. nov. based on its description (this study); B. aggregatus, based on a drawing of a type specimen (plate 4 in Herre 1940); B. kabiliensis, based on the drawing of the holotype (fig. 19 in Inger 1958); and B. nunus, based on the drawing of a specimen of Gobius alcockii Annandale, 1906 (fig. 1 in Annandale 1906), a junior synonym of B. nunus, and the description of B. nunus by Hamilton (1822). Red arrowheads indicate diagnostic differences. Right column: photographs of live non-type specimens illustrating the corresponding left schematic patterns (all photos from the authors).

Live photographs of four paratypes of Brachygobius jennie sp. nov., illustrating intra-specific marking pattern.

Photographed by Mr. Haocong Yang and Mr. Danyang Zhou.

Brachygobius jennie sp. nov. 

 Jiangyan Tian, Jianyong Wu, Chunliu Lan, Sébastien Lavoué and Jianrong Huang. 2026. Brachygobius jennie, A New bumblebee goby (Teleostei, Oxudercidae) from Hengqin Island, Guangdong Province, China. Zoosystematics and Evolution. 102(3): 853-863.  DOI: doi.org/10.3897/zse.102.184142 [17 Jun 2026]