[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]

[Ichthyology • 2026] Characidium lilloi • A New Species of Characidium (Characiformes: Crenuchidae) from the Northwestern La Plata Basin in Argentina

Characidium lilloi

Terán, Méttola, Alonso, Montes, Méndez-López, Miranda, Aguilera & Mirande, 2026

DOI: doi.org/10.1643/i2025064  

 x.com/IchsAndHerps

Abstract

Using an integrative approach that combines molecular and morphological analyses, we describe Characidium lilloi, a new species from the Andean portion of the northwestern La Plata basin, specifically from the upper Bermejo and Juramento River basins in Argentina. Specimens were examined for morphometric, meristic, and osteological traits. Genetic analyses based on COI and CYTB sequences were conducted to infer its phylogenetic relationships. The new species is distinguished by a unique combination of morphological characters including an unscaled isthmus, absence of dark stripes or spots on fins, 7–13 regular transversal bars, 14 scales around the caudal peduncle, 35–37 scales in longitudinal series, and highly developed nasal flaps; and molecular evidence. Characidium lilloi, new species, was found to be closely related to C. fasciatum and C. gomesi and represents the first known member of the C2 Clade in the northwestern La Plata basin. Ecologically, C. lilloi, new species, inhabits fast-flowing mountain rivers within the Yungas and Chacoan. This discovery underscores the northwestern La Plata basin as a biogeographic hotspot of endemism and reinforces its importance as a high-priority area for freshwater conservation.

Lateral views of live paratypes of Characidium lilloi.
 CI-FML 8196, 36.8–49.1 mm SL,
Argentina, El Rey National Park, Río Popayán.

Scale bar = 1 cm. 

Characidium lilloi, new species

Etymology.—This species is named in honor of the Argentine naturalist Miguel Lillo (1862–1931), a pioneer who recognized the importance of public investment in science and education. In his commitment to advancing these fields, Lillo donated his personal assets before his death, ensuring the continuity of his legacy through several key institutions. These include the Facultad de Ciencias Naturales e Instituto Miguel Lillo, the Fundación Miguel Lillo, and the Unidad Ejecutora Lillo–CONICET, all of which have played significant roles in the development of science and education in Argentina. The specific name lilloi, thus, not only pays tribute to Lillo’s contributions but also honors the dedication of public workers in Argentina who promote and contribute to the progress of science, education, and technology.   

Guillermo E. Terán, V. Ezequiel Méttola, Felipe Alonso, Martín M. Montes, Alejandro Méndez-López, Guido Miranda, Gastón Aguilera and J. Marcos Mirande. 2026. A New Species of Characidium (Characiformes: Crenuchidae) from the Northwestern La Plata Basin in Argentina. Ichthyology & Herpetology. 114(2):283-298 DOI: doi.org/10.1643/i2025064 [23 June 2026]

  x.com/IchsAndHerps/status/2069532500280381641

Utilizando un enfoque integrador que combina análisis moleculares y morfológicos, se describe Characidium lilloi, una nueva especie proveniente del sector andino del noroeste de la cuenca del Plata, específicamente de las cuencas altas de los ríos Bermejo y Juramento en Argentina. Los ejemplares fueron examinados en cuanto a caracteres morfométricos, merísticos y osteológicos. Se realizaron análisis genéticos basados en las secuencias de los genes mitocondriales COI y CYTB con el fin de inferir sus relaciones filogenéticas. La nueva especie se distingue por una combinación única de caracteres morfológicos incluyendo el istmo sin escamas, ausencia de bandas oscuras o manchas en las aletas, presencia de 7 a 13 barras transversales regulares, 14 escamas alrededor del pedúnculo caudal, 35 a 37 escamas en la serie longitudinal, y lóbulos nasales altamente desarrollados; y evidencia molecular. Characidium lilloi, nueva especie, se encuentra estrechamente relacionada con C. fasciatum y C. gomesi, y representa el primer miembro conocido del Clado C2 en el noroeste de la cuenca del Plata. Desde el punto de vista ecológico, C. lilloi, nueva especie, habita ríos de montaña de corriente rápida, dentro de las ecorregiones de las Yungas y el Chaco. Este hallazgo resalta al noroeste de la cuenca del Plata como un hotspot biogeográfico de endemismos, y refuerza su importancia como una región de alta prioridad para la conservación de ambientes dulceacuícolas.

[Ichthyology • 2026] Leptorhamdia kamilai • Phylogenetic Placement and Description of A New Species of Leptorhamdia (Siluriformes: Heptapteridae) from the Amazon Basin

Leptorhamdia kamilai

Silva, Reia, Souza, Ywamoto & Oliveira, 2026

 

 DOI: doi.org/10.1590/1982-0224-2025-0037  

 

Abstract

Brachyglaniini is a recently described tribe of Heptapterinae, composed of four genera: Brachyglanis, Gladioglanis, Leptorhamdia, and Myoglanis. Expeditions to the Aripuanã and Tapajós River basins revealed an undescribed species of Brachyglaniini, characterized by a conspicuous light-colored band posterior to the head. Our phylogenetic results provide strong evidence that this new Brachyglaniini species belongs to the genus Leptorhamdia and is closely related to L. marmorata and L. aspredinoides. In addition to the color pattern, the new species can be distinguished from its congeners by having 19-22 anal-fin rays and 47 vertebrae.

Keywords: Brazilian shield; Catfish; Integrative taxonomy; Systematics

 Leptorhamdia kamilai
Left column: holotype, DZSJRP 16293, 92.4 mm SL.
Right column: paratypes, LBP 30639, from top to bottom: 66.3 mm SL; 47.8 mm SL; 31.4 mm SL.

Live specimens of Leptorhamdia kamilai, paratype, LBP 30639, 66.3 mm SL. Photographed by Eric V. Ywamoto. 
 Habitat: rio dos Patos, tributary of the upper Arinos River in Tapajós River basin.

Leptorhamdia kamilai, new species

 Diagnosis. Leptorhamdia kamilai can be readily distinguished among its congeners by having a conspicuous light collar-band, yellowish in live specimens, posterior to the head (vs. coloration uniformly throughout body and head, lacking any distinctive bar). Additionally, L. kamilai differs from its congeners by having 19-22 anal-fin rays (vs. 17 in L. essequibensis; 15 in L. marmorata; 32-35 in L. aspredinoides; 12 in L. nocturna, 15-16 in L. schultzi) and by having 46-47 vertebrae (vs. 45 in L. essequibensis; 43 in L.marmorata; 38 in L. nocturna; 56-57 vertebrae in L. aspredinoides and 43 vertebrae in L. schultzi).

Etymology. The specific name, kamilai, honors our dear friend Dr. Kamila Mayumi Duarte Kuabara, an entomologist and lab manager of the Ornithology Department at The Academy of Natural Sciences of Drexel University. A noun in a genitive case.

Gabriel de S. C. Silva, Lais Reia, Camila S. Souza, Eric V. Ywamoto and Claudio Oliveira. 2026. Phylogenetic Placement and Description of A New Species of Leptorhamdia (Siluriformes: Heptapteridae) from the Amazon Basin. Neotrop. ichthyol. 24 (01); DOI: doi.org/10.1590/1982-0224-2025-0037  

[Ichthyology • 2026] Rhinogobius mengyangensis • A New Species of Freshwater Goby (Gobiiformes: Gobiidae) from Sichuan Province, southwestern China

 

Rhinogobius mengyangensis 

X. Liu, Chen, Shu, Huang, K. Liu & Yu, 2026

濛阳吻虾虎鱼  ||  DOI: doi.org/10.3897/zookeys.1280.188225

Abstract

A new species of freshwater goby, Rhinogobius mengyangensis sp. nov., is described from the upper Changjiang River basin in Sichuan Province, China, based on comparative morphology and molecular phylogeny. The new species is sister to Rhinogobius szechuanensis Tchang, 1939 and can be distinguished from its congeners by the following combination of characters: absence of sensory canals and pores on head; cheeks and operculum without spots or stripes; second dorsal fin with 9–11 longitudinal rows of inverted V-shaped or dash-like brown markings; incomplete brownish edges on flank scales below second dorsal fin; branchiostegal membrane bright yellow.

Key words: Biodiversity, freshwater, phylogeny, taxonomy

Rhinogobius mengyangensis sp. nov. alive. 

A. Male, Tuojiang River basin (holotype, IHB 0202506006); B. Female, Tuojiang River basin (Paratype, IHB 0202506007); 

C. Male, Qingyijiang River basin; D. Female, Qingyijiang River basin.

Rhinogobius mengyangensis sp. nov.

 

Diagnosis. Rhinogobius mengyangensis sp. nov. can be distinguished from all congeners except R. szechuanensis by the following combination of features: absence of sensory canals and sensory pores on head; cheeks and operculum without spots or stripes (Fig. 3). It can be distinguished from R. szechuanensis in having the second dorsal fin with 9–11 longitudinal rows of inverted V-shaped or dash-like brown markings (vs with blue spots, some coalescing into vertical bars), incomplete brownish edges on flank scales below second dorsal fin (vs with complete edges), and a bright-yellow branchiostegal membrane (vs white or blue) (Fig. 4).

 Xin Liu, Zhong-Guang Chen, Yi-Fan Shu, Jun-Hao Huang, Kai Liu and Yi Yu. 2026. Rhinogobius mengyangensis : A New Species of Freshwater Goby (Teleostei, Gobiidae) from Sichuan Province, southwestern China. ZooKeys. 1280: 333-347. DOI: doi.org/10.3897/zookeys.1280.188225

[28 May 2026]

[Ichthyology • 2026] Oreonectes weii • A New endemic Species (Cypriniformes: Nemacheilidae) within the Yangtze River Basin and its Monsoon-driven Evolutionary Diversification

Oreonectes weii

Luo, Ling, Cao, Zhou & Huang, 2026

 

魏氏岭鳅  ||  DOI: doi.org/10.3897/zse.102.186155 

Abstract

A new species Oreonectes weii sp. nov., is described that was collected from Shanggao County, Jiangxi Province, China, located at the upper reaches of the Yangtze River Delta. This naming honors the globally distinguished conservation biologist Fu-Wen Wei for his exceptional and pioneering contributions to biodiversity conservation and research. Morphologically, the new species can be distinguished from its congeners by a combination of meristic and morphological characters, including fin-ray counts, body coloration, eye normal, number of lateral-line pores, and gill-raker counts. Genetically, it forms a distinct lineage in the mitochondrial Cyt b-based phylogeny and exhibits a genetic distance of 6.3% from its sister species, O. polystigmus. We further estimated divergence time within the genus Oreonectes, which indicates an origin in the Late Oligocene (~27.06 Ma) and a most recent common ancestor at ~13.91 Ma. Our biogeographic analyses suggest that the Guijiang-Hejiang River Basin likely served as a source area for the genus’ dispersal into adjacent basins, and that the new species probably originated from a dispersal event of its ancestral population from the Pearl River Basin to the Yangtze River Basin during the Late Miocene (~6.78 Ma). Lineage-divergence dynamics indicate that cladogenesis began around 28 Ma, accelerated markedly at ~18 Ma, peaked at ~6 Ma, and subsequently showed a gradual decline. The current diversity pattern of Oreonectes may have been shaped primarily by dispersal mediated by enhanced precipitation under the East Asian monsoon climate, with subsequent erosion-induced geographical isolation likely promoting speciation and diversification within the genus.

Key Words: Biogeography, cryptic species, morphology, taxonomy, phylogeny, Yangtze River

Ecological photographs and habitats.
A, B. Oreonectes weii sp. nov.; C. O. guidongensis; D. O. polystigmus;
E. Outside the cave; F. Inside the cave.

Oreonectes weii sp. nov.

Diagnosis. Oreonectes weii sp. nov. can be distinguished from all other congeners by the following combination of characters: (1) coloration pattern present and irregular black spots scattered on the lateral body surface and caudal fin; (2) eyes normal; (3) well-developed posterior chamber of air-bladder; (4) cephalic lateral-line system with 4 + 10 infraorbital canal pores and six preoperculo-mandibular canal pores; (5) 9–10 branched pectoral-fin rays, length 16.0–24.3% SL; (6) tip of pelvic fin not reaching the anus; (7) caudal fin truncated, with 14 branched caudal-fin rays; (8) 10 inner gill rakers on the first gill arch; (9) tip of maxillary barbel not reaching the posterior margin of the operculum.

Etymology. The specific epithet “weii” is a genitive noun derived from the surname of Academician Fu-Wen Wei (魏辅文), an eminent conservation biologist. The name is given in honor of his outstanding contributions to the study and conservation of biodiversity in China. We suggest the English common name for this species is the “Wei’s Mountain Loach”, and its Chinese name is “Wèi Shì Lǐng Qiū” (魏氏岭鳅).

 Tao Luo, Wen-Qing Ling, Hai-Lin Cao, Jiang Zhou and Guang-Ping Huang. 2026. A New endemic Species Oreonectes weii sp. nov. (Cypriniformes, Nemacheilidae) within the Yangtze River Basin and its Monsoon-driven Evolutionary Diversification. Zoosystematics and Evolution. 102(3): 751-765. DOI: doi.org/10.3897/zse.102.186155 [14 May 2026]

[Ichthyology • 2026] Solenostomus snuffleupagus • A hairy Ghost Pipefish (Syngnathiformes: Solenostomidae) from the Southwest Pacific, with an integrative comparison to S. paegnius

Solenostomus snuffleupagus

Short & Harasti, 2026   

DOI: doi.org/10.1111/jfb.70497

 

Abstract

A new species of ghost pipefish, Solenostomus snuffleupagus sp. nov., is described from the Coral Sea based on specimens (18–34 mm SL) collected from coral reef habitats in Queensland, Australia. The species is diagnosed by the following combination of characters: abundant elongate integumentary filaments imparting a conspicuously shaggy appearance; 36 total vertebrae (vs. 32–34 in all congeners); compact body form with a short, deep pretrunk (11%–14% SL); sexually dimorphic supraoccipital crests (moderately elevated in females, strongly developed in males); and two modified anchor-like ossicles spanning the pterygiophores in both soft dorsal and anal fins. Micro-CT imaging reveals distinctive pretrunk ossicle configuration characterized by deep angular interspaces and absence of a ventral ossicle series. Mitochondrial COI sequences indicate an uncorrected p-distance of 22.0% from the superficially similar S. paegnius, a species with which it has long been confused in museum collections and citizen science databases. Field observations document consistent association with dense filamentous red macroalgae, with body coloration closely matching host substrate. The species is currently known from the southwest Pacific, including northeastern Australia (Coral Sea), Papua New Guinea, New Caledonia, Fiji and Tonga, representing a southwestern Pacific distribution.

Solenostomus snuffleupagus, in situ, Great Barrier Reef, Australia, 2022: (a) adult individual; (b) female specimen used for genetic analysis; (c) male specimen used for genetic analysis (photographs by David Harasti).

Micro-CT reconstructions (lateral view) of Solenostomus snuffleupagus:
(a) holotype, female, AMS I.33751-047; (b) paratype, male, NTM S.13600–047. DF, dorsal-fin; PF, pectoral-fin; sAF, soft anal-fin; sDF, soft dorsal-fin. Numbers 1 and 2 indicate the respective pterygiophores supporting the soft dorsal- and anal-fins.

 Taxonomy

Family Solenostomidae 

Genus Solenostomus Lacépède 1803 

 Solenostomus snuffleupagus, Short and Harasti, new species

Diagnosis: A species of Solenostomus distinguished from its congeners by the following combination of characters: body compact and vertically deep anteriorly; pretrunk deep (24.4%–29.2% SL); abundant, elongate integumentary filaments conferring a conspicuously shaggy appearance, particularly dense on snout, jaws, head and fin extremities; pretrunk ossicles are narrow and elongated, separated by deep angular interspaces, forming a distinctive compact lattice; There are total 36 vertebrae. The supraoccipital crest is elevated and rounded in females, but strongly pronounced in males. There are two modified anchor-like ossicles spanning the pterygiophores in both the soft dorsal fin (19–20 rays) and anal fin (18–19 rays). The soft dorsal fin has 19–20 rays, the anal fin has 18–19 rays, the pectoral fin has 27 rays, the caudal fin has 15 rays.

Etymology: The specific epithet snuffleupagus refers to the shaggy character Mr. Snuffleupagus, also known as ‘Snuffy’, from the children's television series Sesame Street™, in allusion to the species' distinctly shaggy, filamentous appearance and snout reminiscent of the character's covering and trunk. The name is treated as a noun in apposition (ICZN Article 31.1.2).

Solenostomus paegnius, in situ: (a) Indonesia (photograph by Richard Smith); (b) Philippines, male–female pair with the female positioned above the male in the water column (photograph by Lynn Funkhouser); (c) Philippines, male–female pair with the female positioned above the male in the water column (photograph by Alex Tyrrell @dive4photos).

 

Graham Short and David Harasti. 2026. Solenostomus snuffleupagus sp. nov., A hairy Ghost Pipefish (Teleostei: Solenostomidae) from the Southwest Pacific, with an integrative comparison to S. paegnius. Journal of Fish Biology. DOI: doi.org/10.1111/jfb.70497 [10 May 2026]

 

[Ichthyology • 2026] Hemigrammus serrazul • A New Hemigrammus (Characiformes: Acestrorhamphidae) from the rio Cuiabazinho Drainages, upper rio Paraguai Basin, Mato Grosso, Brazil

   

Hemigrammus serrazul  

Ferreira, Ribeiro & Carvalho, 2026

DOI: doi.org/10.1590/1982-0224-2025-0157

 

Abstract

A new species of Hemigrammus is described from tributaries of the rio Cuiabazinho, upper rio Paraguai basin, Mato Grosso State, Brazil. It can be readily distinguished from all its congeners by a unique combination of characters, including a distinctive body coloration pattern without spots, the number of perforated lateral-line scales (12–15), the number of branched rays on anal fin (21–25), and the presence of small bony hooks at the tips of the lepidotrichia of the second to fourth branched rays of the pelvic fins, which are absent in the anal fin. We also provide a brief discussion on the recent taxonomic reconfiguration of Hemigrammus.

Keywords: Freshwater fish; Rio Cuiabá drainage; Serra Azul; Serrana Province of Mato Grosso; Taxonomy

 Color pattern variations in live specimens of Hemigrammus serrazul: A. Male; B. Female.

Photo by Alexandre C. Ribeiro.  

Hemigrammus serrazul, new species

Diagnosis. Hemigrammus serrazul can be distinguished from most congeners (except of H. apiaka (Esguícero& Castro, 2017), H. erythrozonus Durbin, 1909, H. gracilis (Lütken, 1875), H. mimus Böhlke, 1955, and H. tupebas (Esguícero& Castro, 2017) by flank uniformly colored, without spots, i.e., no humeral and caudal spots, just a tiny and narrow longitudinal stripe (vs. species with spots in humeral and/or caudal peduncle). From H. apiaka, H. erythrozonus, H. gracilis, H. mimus, and H. tupebas, H. serrazul differs by premaxillary teeth in two rows: outer with three to five tricuspid teeth, inner with five ...

Etymology. The specific epithet serrazul refers to the type locality where the new species was collected, the Serra Azul, the local portion of the so-called Serrana Province of Mato Grosso, a range of escarped relief that serves as a watershed divide between the rio Cuiabá, Paraguai, and Arinos basins. A noun in apposition.

Hemigrammus serrazul, live specimen in aquarium, photographed just after capture in córrego Cocal (CPUFMT 8218), upper rio Paraguai basin, municipality of Rosário Oeste, Mato Grosso State, Brazil. Inserir:

Photo by Alexandre C. Ribeiro.

Katiane Mara Ferreira, Alexandre Cunha Ribeiro and Fernando Rogério Carvalho. 2026. A New Hemigrammus (Characiformes: Acestrorhamphidae) from the rio Cuiabazinho Drainages, upper rio Paraguai Basin.  Neotrop. ichthyol. 24 (01); DOI: doi.org/10.1590/1982-0224-2025-0157

[Ichthyology • 2026] Tympanopleura personata • A New Species of inseminating Catfish of the Genus Tympanopleura (Siluriformes: Auchenipteridae) from the Ituxi River, Amazon River Basin, northern Brazil, revealed by integrative taxonomy

Tympanopleura personata

 Ribeiro, Silva-Oliveira, Magalhães, Gama & Py-Daniel, 2026

DOI: doi.org/10.1111/jfb.70445 

Abstract

A new species of the genus Tympanopleura is described from the Iquiri River, a tributary of the Ituxi River, a right-bank tributary to the Purus River, Amazon River, northern Brazil. The new species is distinguished from all its congeners by a combination of features, such as the presence of an intensely pigmented square-shaped blotch on the supraoccipital, a semicircular dark blotch above each eye and an inconspicuous vertical bar on the caudal-fin base (except Tympanopleura piperata), and by a combination of meristic and morphometric character states. Preliminary molecular analyses demonstrate genetic distance values of 2.4% of cytochrome oxidase, subunit I, divergence between the new species and T. piperata and 8.0%–13.0% between the new species and the other congeners. The new species shows several reproductive adaptations to copulation and internal insemination. Considering the period during which prenuptial and nuptial specimens were available, we can presume that its reproductive period occurs when the water level increases. In addition, an identification key for the species of Tympanopleura is provided.

Tympanopleura personata in life, in dorsal (a) lateral, (b) ventral views and (c) dorsal views, UFOPA-I 1374, 84.0, mm LS, paratype, Iquiri River, Lábrea, Amazonas, Brazil.

  Tympanopleura personata, new species

Diagnosis: Tympanopleura personata is distinguished from all congeners by having a unique colouration of the head, consisting of the combination of an intensely pigmented square-shaped blotch on the supraoccipital and a semicircular dark blotch above each eye (Figure 2; Walsh et al., 2015: Figure 1e). It also differs from all congeners, except T. piperata, by the caudal-fin pigmentation, consisting of a patch of scattered melanophores forming an inconspicuous vertical bar on the caudal-fin base, most visible in live or freshly preserved specimens (Figure 2). Tympanopleura personata differs from T. piperata by having a longer caudal peduncle (11.1%–13.8% LS vs. 7.6%–10.5% LS) and a smaller distance between the insertion of the last dorsal-fin ray and adipose-fin origin (41.9%–45.6% LS vs. 45.9%–55.4% LS). Additionally, T. personata can be distinguished from T. atronasus, T. cryptica, T. brevis, T. piperata and T. rondoni by having more anal-fin rays (36–40, mode 39 vs. 23–30, mode 27 in T. atronasus; 23–30, mode 29 in T. cryptica; 31–36, mode 33 in T. brevis; 31–38, mode 35 in T. piperata; and 28–37, mode 31 in T. rondoni) and few total gill rakers (17–20, mode 19 vs. 20–24, mode 23 in T. brevis; 21–26, mode 22 in T. cryptica; 19–25, mode 23 in T. longipinna; and 24–33, mode 29–30 in T. rondoni).

Etymology: The specific epithet personata is derived from the Latin personatus, meaning masked, in reference to the dorsal pigmentation of the head. It is treated as a noun in apposition. Gender is feminine.

Frank Raynner V. Ribeiro, Cárlison Silva-Oliveira, Valdenor Magalhães, Lucas Gama and Lúcia H. Rapp Py-Daniel. 2026. A New Species of inseminating Catfish of the Genus Tympanopleura (Siluriformes: Auchenipteridae) from the Ituxi River, Amazon River Basin, northern Brazil, revealed by integrative taxonomy. Journal of Fish Biology. DOI: doi.org/10.1111/jfb.70445 [13 April 2026]