Skip to main content

Iridescent chub (Opsariichthys iridescens), an upstream river fish with gravel substrate from Southeast China

Iridescent chub (Opsariichthys iridescens), an upstream river fish with gravel substrate from Southeast China

NEWS - Iridescent chub (Opsariichthys iridescens) from the Qiantang and Oujiang rivers in Zhejiang Province and adjacent Yangtze River tributaries to the Qiantang River was established as a new species based on its unique morphology and gene sequence divergence from all congeners and monophyly recovered in a Cyt b gene-based phylogenetic analysis.

Opsariichthys Bleeker, 1863, is a group of small cyprinid fishes endemic to East Asia that inhabit fast-flowing rivers or streams. The type species, Opsariichthys uncirostris Temminck & Schlegel 1846, was originally described in the genus Leuciscus Cuvier 1816. A phylogenetic study based on mitochondrial genomes in 2017 confirmed lateral bars as the main diagnostic feature of the opsariichthys group.

Opsariichthys is currently considered to include 14 valid species with 8 of them distributed throughout mainland China. Valid species in mainland China are O. acutipinnis Bleeker 1871, O. amurensis Berg 1932, O. bidens Günther 1873, O. chengtui Kimura 1934, O. evolans Jordan & Evermann 1902, O. hainanensis Nichols & Pope 1927, O. macrolepis Yang & Hwang and O. minutus Nichols 1926.

While examining specimens collected from Zhejiang Province and adjacent Yangtze tributaries to the Qiantang River, researchers found several specimens did not belong to any described species. Further morphological and molecular analyses supported that they belonged to a new species.

O. iridescens can be well distinguished by the absence of a distinct anterior notch on the upper lip (vs. the presence of a distinct deep anterior notch on the upper lip in O. uncirostris, O. amurensis, O. minutus, O. hainanensis, O. dienbienensis Nguyen & Nguyen 2000, O. songmaensis Nguyen & Nguyen 2000, O. acutipinnis, O. chengtui, O. macrolepis, O. kaopingensis Chen & Wu 2009, O. pachycephalus Günther 1868 and O. duchuunguyeni Huynh & Chen 2013).

The new species is also distinguished from conspecifics by 45-52 lateral line scales, 9-10 scales above lateral line, 18-21 pre-dorsal scales, 16-17 circum-peduncular scales and two rows of pharyngeal teeth. In adult males, the upper jaw extends to or slightly beyond the vertical anterior margin of the orbit, the pectoral fins extend to the pelvic fins, are nearly uniform (narrow, pale bar on the trunk, significantly widened on the caudal peduncle), the nuptial tubercles on the cheeks and the lower jaw are fused basally to form a plate.

O. iridescens lives in the upper reaches of rivers with moderate flow speeds and clear water with gravel and small to medium-sized boulders as the substrate. Iridescens is the Latin form of the word iridescent. The term refers to the unique body coloration that is brighter than other known species in the genus. The researchers propose the Chinese common name Hóng Cǎi Mǎ Kǒu Yú (虹彩马口鱼).

Based on this new classification, the researchers establish O. acutipinnis, O. evolans and O. macrolepis previously known as Zacco platypus as valid species of Opsariichthys. O. amurensis, O. minutus and O. hainanensis previously considered synonymous with O. bidens were also revalidated. O. chengtui and O. pachycephalus was moved from Zacco to Opsariichthys, while the status of O. bea (Nguyen 1987) and O. hieni (Nguyen 1987) remains uncertain.

Original research

Peng X, Zhou J-J, Gao H-D, Yang J-Q (2024). A new species of Opsariichthys (Teleostei, Cypriniformes, Xenocyprididae) from Southeast China. ZooKeys 1214: 15-34, DOI:10.3897/zookeys.1214.127532

Dlium theDlium
Labels:

Popular Posts

Bugang (Clerodendrum calamitosum)

Bugang ( Clerodendrum calamitosum ) is a species of plant in the Lamiaceae family. It is an erect shrub, growing up to 1 meter tall, with cylindrical, green stems and white hairs. The leaves are opposite. The leaf blade is oval, wavy, with a central main vein with numerous pinnate minor veins, and serrated margins. The leaves are up to 9 cm long and 7 cm wide. The petiole is up to 2 cm long. The flowers are star-shaped, white, up to 3 cm in diameter and up to 6 cm in total length. The fruit is round, dark green, turning black when ripe. TAXON Kingdom: Plantae Phylum: Tracheophyta Subphylum: Angiospermae Class: Magnoliopsida Order: Lamiales Family: Lamiaceae Subfamily: Ajugoideae Genus: Clerodendrum L. in Sp. Pl.: 637 (1753) Species: Clerodendrum calamitosum L. in Mant. Pl. 1: 90 (1767) HETEROTYPIC SYNONYMS Clerodendrum fastigiatum (W.Hunter ex Ridl.) H.J.Lam in Verben. Malay. Archip.: 317 (1919) Volkameria alternifolia Burm.f. in Fl. Indica: 137 (1768) Volkameria fastigiata W.Hunter...
Read more

Plumeria rubra and Plumeria obtusa, the differences

SPECIES HEAD TO HEAD - The genus frangipani trees ( Plumeria Tourn. ex L.) has only 18 officially recorded species and two very similar species, frangipani ( Plumeria rubra L.) and white frangipani ( Plumeria obtusa L.). Both have the same habitus, flowers and fruits and are difficult to distinguish. The leaves of both species have slightly different shapes. Therefore, the leaves are very important to distinguish the two species, especially the shape of the tip. P. rubra has simple, lanceolate leaves with acute tips. P. obtusa has simple, elliptic leaves with rounded tips. By Aryo Bandoro Founder of Dlium.com . You can follow him on X: @Abandoro . Read more: Plumeria rubra Plumeria obtusa
Read more

Common sun skink (Eutropis multifasciata)

Kadal kebun or bengkarung or Mabuya multifasciata or common sun skink ( Eutropis multifasciata ) is a species of lizard in Scincidae, has a pattern of faint lines extending to the sides of the body, measuring 18 to 22 cm in length with a tail length of about 60% of the overall body and more many live on the ground. E. multifasciata has a sharp head with a very short neck and a square cross section. The upper part is dark brown or shiny grayish brown with a golden body side especially near the neck. Sometimes also decorated with small pale spots on the back. The lower neck is light brown and the abdomen to the anus is pale brown. The muzzle is reddish, the tail is the same color as the body, decorated with a faint dark line on the sides. The arms are also the same color as the upper body. Common sun skinks usually live on the edge of forests, gardens, rice fields and human settlements. They spend most of their time on the ground, usually in crevices and rocky cliffs as a place t...
Read more