Channa nox, a new channid fish lacking a pelvic fin from Guangxi, China

 A new species of channid fish, genus Channa, is described from 7 specimens collected from the vicinity of Hepu, Guangxi Province, southern China. The new species, Channa nox, is distinguished from all other channid species by the following combination of characters: absence of pelvic fins, small rounded head (22.1%–26.8% SL), narrow interorbital width (19.6%–26.7% HL), short snout length (3.6%–5.1% SL), predorsal and prepectoral lengths (26.9%–28.4% SL and 24.8%–28.3% SL, respectively), 47–51 dorsal fin rays, 31–33 anal fin rays, 55–63 lateral line scales, 5.5–6.5 scales above lateral line, 9–13 cheek scales, 53–55 total vertebrae, 1 or 2 scale(s) on each side of lower jaw undersurface, the black upper half of body with 8–11 irregular (often anteriorly pointed V-shaped) bands or blotches, a large white-rimmed black ocellus on caudal peduncle and sparse white spots on the dark brown body and dorsal and caudal fins, as well as the shape of the hyomandibular process of the suprabranchial organs. Channa nox is sympatrically distributed with its morphologically most similar congener, C. asiatica. Received: January 18, 2001 / Revised: November 2, 2001 / Accepted: December 12, 2001     

Psilorhynchus nahlongthai,a new fish species (Teleostei: Psilorhynchidae) from the Brahmaputra drainage,northeast India

Psilorhynchus nahlongthai, a new psilorhynchid fish, is described from the Diyung River, a tributary to the Kopili River (itself a southern tributary of the Brahmaputra drainage) in Assam, northeast India. It is placed in the Psilorhynchus balitora species group and can be easily distinguished from all other members of this group by a combination of the following characters: dense and prominent tuberculation on the head region; thick and long pre- and post-epiphyseal fontanelles on the neurocranium; 9 + 8 caudal-fin rays; and 34 (24 + 10) vertebrae. Genetic divergence between P. nahlongthai and members of the P. balitora species group from the Brahmaputra and neighbouring drainages, with K2P distances ranging 3.7%–14.7% and 7.4%–20.7% in the mitochondrial COI and cyt b gene datasets respectively, support its report as a new species.     

Channa panaw, a new channid fish from the Irrawaddy and Sittang River basins, Myanmar

Channa panaw sp. nov. (Channidae) is described from 32 specimens collected from the Irrawaddy and Sittang River basins, Myanmar. It is distinguishable from all known congeners by the combination of the following characters: 32–35 dorsal fin rays, 23–24 anal fin rays, 17–20 pectoral fin rays, 39–41 lateral line scales, 39–41 total vertebrae, one large scale on each side of the lower jaw (rarely 2 on one side), pelvic fin length always more than 50% of pectoral fin length, and 7–12 irregular black blotches on the upper half of the body.     

Acrossocheilus multistriatus,a new species of barbine fish(Teleostei: Cyprinidae) from the Zhujiang River basin,South China

A new barbine cyprinid fish, Acrossocheilus multistriatus sp. nov., is described from the Zhujiang River(Pearl River) basin in South China. It is separated from all other barred congeners except A. monticola by its unique coloration pattern of 8–12 vs. 5–7 vertical dark bars on the dorsum and flank. Although 8 vertical black bars are also present in specimens of A. monticola, the new species is distinct from it by having a well-developed(vs. poor-developed) lower lip, with or without a median interruption(vs. with a median interruption which wider than 1/2 mouth width) on lower jaw, the lower jaw entirely covered(vs. uncoverd) by the lower lip, body depth 22.57%–25.22% SL(vs. 25.64%–32.26% SL). Additional characteristices as follows: last simple dorsal-fin ray soft without serration; dark stripes on membranes between dorsal-fin rays; dark stripes absent on membranes between anal fin rays; maxillary barbels longer than eye diameter, extending to posterior edge of eyes.     

Rotifer communities of floodplain lakes of the Brahmaputra basin of lower Assam (N.E. India): biodiversity, distribution and ecology

The rotifer communities of 15 acidic – alkaline and soft – marginally hard water floodplain lakes of the lower Assam valley of the Brahmaputra river basin, characterized by low ionic concentrations, reveal 164 species (178 taxa) belonging to 39 genera and 20 families and represent the richest biodiversity known to date in these ecotones of the Indian subcontinent. Nine species are new to the Indian Rotifera. Cosmopolitan (59.7%) > pantropical (15.2%) > cosmotropical (12.2%) species dominate the taxocoenosis. Biogeographically interesting elements constitute a notable component (13.4%); important members of this category include six Oriental, two Australasian and seven Palaeotropical species. The examined fauna depicts a tropical character with predominance of Lecanespp. (28.0%). Littoral or periphytic rotifers (76.2%) dominate the planktonic species. Rotifers comprise a dominant qualitative (67–103, 79.1±11.0 species) and an important quantitative (mean: 41.1–65.9%) component of zooplankton in all floodplain lakes, register a moderate diversity (mean: 2.036–2.642), low dominance (mean: 0.019–0.216) and high evenness (mean: 0.840–0.893). The examined material indicates several interesting acidophilous elements. Richness depicts significant inverse correlation with pH. Water temperature, conductivity, dissolved oxygen and alkalinity record significant direct relationships with the rotifer abundance. Diversity is influenced by abundance and is also directly correlated with water temperature and conductivity. Canonical analysis shows a notable cumulative impact of six abiotic factors on richness, density and diversity.     

A new species, Polydactylus siamensis, from Thailand and redescription of P. plebeius (Broussonet, 1782) with designation of a neotype (Perciformes: Polynemidae)

A new species, Polydactylus siamensis, is described on the basis of eight specimens from Thailand. The species is similar to P. plebeius (Broussonet, 1782) in having five pectoral filaments and several dark stripes along the scale rows above and below the lateral line, but differs from the latter in having lower counts of pectoral fin rays (15 vs. 16–18 in P. plebeius), pored lateral line scales (54–58 vs. 60–68), scale rows above and below the lateral line (7 and 10 or 11, respectively vs. 8 or 9 and 12 or 13, respectively) and gill rakers (9 or 10 upper series, 13 or 14 lower and 22–24 total vs. 9–14, 13–18 and 24–32, respectively), and a longer upper jaw (mean 17% [range 16–17%] of standard length vs. 15% [13–16%]). Polydactylus siamensis is currently known only from Bangkok and Songkhla, Gulf of Thailand, and Phuket Island, Andaman Sea, whereas P. plebeius is widely distributed in the Indo-Pacific. Received: January 12, 2000 / Revised: September 15, 2000 / Accepted: January 12, 2001     

Length–weight relationships of three freshwater fish species from the Kameng River (Brahmaputra basin) in Arunachal Pradesh,northeast India

Length–weight relationships (LWRs) for three fish species, Psiloryhnchus homaloptera Hora & Mukherji, 1935, Pseudecheneis sulcata (McClelland, 1842) and Devario aequipinnatus (McClelland, 1839), from the Kameng River in Arunachal Pradesh, India were estimated from August 2016 to October 2017. Fishes were collected seasonally using cast nets (2.5 m, 1.2 cm) and electrofishing device (Safari Surveyor, 12 V 7 amp). The b values in the LWRs were determined as 2.98, 2.93 and 2.72 for P. homaloptera, P. sulcata and D. aequipinnatus respectively. The coefficient of determination (r² > .95) for all the species is statistically significant.     

Two new species of Cololejeunea (Spruce) Schiffn. from Western Ghats,India

Introduction. During a recent floristic survey of liverworts from Western Ghats, India, two interesting liverworts of genus Cololejeunea were collected from forests in Mahabaleshwar in the state of Maharashtra.

Methods. After critical investigation, they have been described as new to science and both species, C. ghatensis G.Asthana & A.Srivastava sp. nov. and C. mehrana G.Asthana & A.Srivastava sp. nov. are illustrated and described here.

Key results. Cololejeunea ghatensis is an epiphyllous species growing on angiosperm leaves and has been collected near Chinaman Waterfall, Robbers Cave, Connaught Peak and Polo Ground area. Cololejeunea mehrana has been collected near Monkey point and the latter has an interesting habitat as it was found growing on moss leaves. Cololejeunea ghatensis is monoicous and C. mehrana is dioicous.     

Description of a new species of Mustura Kottelat (Teleostei: Nemacheilidae) from the Brahmaputra drainage,India

Mustura subhashi, new species, is described from the Dikal River, a north bank tributary of the Brahmaputra drainage in Arunachal Pradesh. It is distinguished from all its congeners by having a colour pattern of 14–23 dark-greyish black to dark brown irregular bars on a greyish to pale beige body; pre-dorsal bars thin, numerous, wider than interspaces, weakly contrasted, uniting dorsally at lateral one-third or midway on flank to form thicker bars, coalescing further at lateral one-fifth and continuous on dorsum with contralateral bars; bars below dorsal fin exhibiting similar condition but slightly wider than pre-dorsal bars; post-dorsal bars thicker than anterior bars, wider than interspaces, sharply contrasted, rarely coalescing on flank; and a short bar along the caudal mid-line, rarely forming a blotch. Based on re-examination of the type specimens and additional materials, Mustura dikrongensis is confirmed as a species belonging to Mustura, and M. harkishorei is not sufficiently diagnosed from 'Nemacheilus' corica.     

A redescription of Heterocotyle pastinacae Scott, 1904 (Monogenea: Monocotylidae) from Dasyatis pastinaca (Dasyatididae), with a neotype designation

Heterocotyle pastinacae Scott, 1904 is redescribed and a neotype is designated. H. pastinacae is most easily distinguished from other members of the genus by the elaborate arrangement of sclerotised spines in the vagina. The male copulatory organ also serves to differentiate it from other species in the genus. A possible function for the vaginal spines and unique form of the male copulatory organ is discussed. The use of head organ number as a generic character is considered questionable.     

Pterygiella luzhijiangensis sp. nov. (Orobanchaceae), a new procumbent species from Yunnan,southwest China

Pterygiella luzhijiangensis Huan C. Wang, is described and illustrated as a new species endemic to Yunnan, southwest China. It occurs in thickets of the Luzhijiang hot‐dry valley at elevations of 1000–1300 m a.s.l. This new species is closely related to P. duclouxii Franch., but clearly differs from the latter by its procumbent stems, much branched at the base, 7–20 cm long, the leaves 1.0–2.2 cm long, 0.1–0.2 (0.25) cm wide, the corolla 2.0–2.2 cm long, obviously longer than the calyx, with the lower lip of the corolla much longer than the upper one.     

Indo-West Pacific species of the genus Stylopoma Levinsen, 1909 (Bryozoa: Cheilostomatida)

Twenty-one species of Stylopoma Levinsen, 1909 are described and illustrated with scanning electron micrographs. S. spongites (Pallas, 1766), the type species, is redescribed from the neotype specimen and included here for completeness. A neotype specimen for S. duboisii (Audouin, 1826) and a lectotype specimen for S. viride (Thornely, 1905) are designated and 14 new species of Stylopoma are described from Indo-West Pacific material in the Recent bryozoan collections of the Natural History Museum, London.     

Mysidacea (Crustacea) from the Minicoy lagoon (Lakshadweep, India) with description of a new species of Anisomysis

Four species of mysids collected from the Minicoy lagoon are reported. Anisomysis minicoyensis sp. nov. is distinguished from the related species by the shape of the rostrum, the relative length of the antennal scale and the short protuberances on the second segment of the mandibular palp. The other three species recorded are Siriella australiensis, Anisomysis truncata and unidentified species of subfamily Gastrosaccinae.     

Length‐weight relationships of five fish species collected from Ranganadi River (Brahmaputra River tributary) in Assam,India

Length‐weight relationships (LWR) are presented for five fish species: Laubuka laubuca (Hamilton, 1822); Aspidoparia jaya (Hamilton, 1822); Channa gachua (Hamilton, 1822); Acanthocobitis botia (Hamilton, 1822) and Badis badis (Hamilton, 1822) collected from the Ranganadi River in the Lakhimpur district of Assam, India. There were no prior LWR data regarding three of these species.     

Knodus dorsomaculatus (Characiformes: Characidae), a new species from Teles Pires River,Tapajós River basin,Brazil

Knodus dorsomaculatus, a new species, is described from Teles Pires River, a tributary of the Tapajós River, Brazil. It can be distinguished from its congeners by the presence of a conspicuous dark blotch on the base of the first five branched dorsal fin rays and the presence of ii,9 dorsal fin rays. Additional comparisons between K. dorsomaculatus and its congeners are presented.