Taxonomy & naming
Tachysurus pseudovirgatus was described in 2026 by Weihan Shao and E Zhang in a large integrative-taxonomy revision published in the journal Animals (MDPI). The paper re-examined “Tachysurus virgatus” (Oshima, 1926) sensu lato, a striped bagrid long treated as a single species distributed from Hainan Island to central Vietnam. Combining mitochondrial sequence data with detailed morphometrics, the authors found that specimens assigned to T. virgatus actually represent ten distinct, mostly narrow-range lineages; true T. virgatus is now restricted to the Wanquan River on Hainan Island, and nine of the remaining lineages — including this species — were formally described as new in the same paper, joining T. spilotus and T. kyphus to form the newly defined Tachysurus virgatus species group.
Within that group, T. pseudovirgatus falls in “Clade I” and in a coloration-based “morph-group B” together with T. virgatus, T. trimaculatus, T. bailongensis and T. furcatus — all species with an unconstricted, uniformly wide mid-lateral stripe. Phylogenetically it is sister to T. virgatus itself, from which it differs by only 2.7% in the mitochondrial cyt-b gene, a genetic distance the authors describe as falling in the “grey zone” of speciation where diagnostic traits accumulate asynchronously with molecular divergence. The epithet pseudovirgatus (Greek pseudo-, “false”, prefixed to virgatus) records exactly this: a species so close to T. virgatus in appearance that it was mistaken for it until integrative analysis separated the two.
The holotype (catalog number IHB 201909112589, 2.33 in SL) and seven paratypes (2.08–2.26 in SL) were collected by Weihan Shao in September 2019 from a stream feeding the Dong River, a tributary of the Pearl River, in Boluo County, Guangdong Province. Catalog of Fishes (Eschmeyer, California Academy of Sciences) lists Tachysurus pseudovirgatus Shao & Zhang, 2026 as the currently valid combination.
Morphology
Like other members of the T. virgatus group, T. pseudovirgatus carries two continuous black longitudinal stripes running from the head to the caudal peduncle, with the mid-lateral stripe splitting at the caudal-fin base into two short stripes that run onto the caudal-fin lobes, and paired semicircular black markings at the caudal-fin base. The original description diagnoses it, among the other striped species with a deeply forked caudal fin and straight-edged lobes, by the absence of a connection between the dorso-lateral stripe and the black opercular blotches (present in T. bailongensis and T. trimaculatus), a narrower caudal peduncle (33.5–41.3% of head length, versus 42.1–45.3% in its close relative T. furcatus), and a narrower whitish-yellow patch behind the eye than in T. virgatus.
Meristic counts recorded from the type series: 7 dorsal-fin rays, 14–15 anal-fin rays, 7 pectoral-fin rays, 6 pelvic-fin rays and 30–32 total vertebrae. As in other bagrids, the skin is entirely scaleless, and the leading rays of the dorsal and pectoral fins are stiffened into serrated, lockable spines — a genus-level feature, not something verified specifically for this species but standard across Tachysurus.
The type series ranges from 2.08–2.33 in standard length, with the 2.33 in holotype the largest measured specimen. Because sampling to date has been confined to a single stream, this is best read as the known size range of the type series rather than a confirmed adult maximum — larger individuals may exist but have not been documented.
Habitat
Tachysurus pseudovirgatus is currently known only from Boluo County, Guangdong Province, in a stream feeding the Dong River, itself a tributary of the Pearl River. All recorded specimens came from flowing stream habitat rather than the river mainstem, placing the species among the seven “obligate stream-dwelling” members of the T. virgatus group identified in the 2026 revision — fish restricted to montane or upland stream reaches with higher flow velocity, coarse gravel or boulder substrate and well-oxygenated water, as opposed to the slower, siltier mainstem habitats used by some of its relatives.
No water-chemistry measurements (temperature, pH, hardness) have been published for the type locality. No occurrence beyond the single collecting stream has yet been reported in the literature.
Feeding
No feeding, spawning or captive-husbandry data has been published for this species; it is known only from the type series collected for the 2026 taxonomic revision. As a genus-level generality, Tachysurus species are nocturnal benthic predators that use their barbels to locate invertebrate prey — aquatic insect larvae, small molluscs and crustaceans — on and in soft or gravel substrate after dark; the related T. fulvidraco, for which gut-content studies exist, feeds heavily on caddisfly and midge larvae. Whether T. pseudovirgatus follows this pattern has not been confirmed.
Mating
No feeding, spawning or captive-husbandry data has been published for this species; it is known only from the type series collected for the 2026 taxonomic revision. No sex-linked size or color difference was reported in the type series, and the specimens do not appear to have been sexed in the original description. Related Tachysurus species pair up for spawning in spring and summer, a genus-level pattern that has not been confirmed for this species.
Breeding
No feeding, spawning or captive-husbandry data has been published for this species; it is known only from the type series collected for the 2026 taxonomic revision. Bagrids in this genus, where studied, are cavity or sheltered-substrate spawners with the male guarding the eggs — documented in detail for the commercially farmed T. fulvidraco, but this is genus-level context, not a specific finding for T. pseudovirgatus, which has never been kept or bred in captivity as far as the published record shows.
In the aquarium
Tachysurus pseudovirgatus is not established in the aquarium trade and, as a species described in 2026 from a single small stream, is unlikely to become available through normal commercial channels; no husbandry accounts exist for it. If specimens were ever encountered, the safest approach is to extrapolate cautiously from genus-level Tachysurus/Bagridae care: cool to moderate, well-oxygenated, flowing water reflecting its stream habitat; soft or fine gravel substrate for the barbels to probe; shelter for a fish that is presumably nocturnal and benthic like its relatives; and the standard bagrid handling caution — the dorsal and pectoral spines lock and can snag in a net, so a container is safer for transfers than a net. Given the species' documented population decline and restricted single-locality range, any live specimens encountered in trade would raise serious conservation concerns and should not be collected from the wild.
Conservation
Tachysurus pseudovirgatus has not yet been formally assessed by the IUCN Red List; as a species named in 2026 it currently carries no status. The authors of the describing paper, however, explicitly evaluated it against IUCN criteria as part of their revision and recommend Endangered status under Criterion B1a,b. Their reasoning: the species is known from a single locality with a small population, it lies close to the Pearl River Delta — China's largest urban agglomeration — and it has undergone pronounced population decline over the past decade attributed to intensive urbanization pressure in that region.
This makes T. pseudovirgatus one of two species in the T. virgatus group (with T. platystomus) singled out for the group's most urgent conservation status. Because it is currently known from a single stream, any habitat disturbance, water abstraction or pollution event there would carry outsized risk for the species as a whole. No conservation program specific to this species has been reported.