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Balitorid loaches are a family of fishes that exhibit morphological adaptations to living in fast flowing water, including an enlarged sacral rib that creates a ‘hip’-like skeletal connection between the pelvis and the axial skeleton. The presence of this sacral rib, the robustness of which varies across the family, is hypothesized to facilitate terrestrial locomotion seen in the family. Terrestrial locomotion in balitorids is unlike that of any known fish: the locomotion resembles that of terrestrial tetrapods. Emergence and convergence of terrestrial locomotion from water to land has been studied in fossils; however, studying balitorid walking provides a present-day natural laboratory to examine the convergent evolution of walking movements. We tested the hypothesis that balitorid species with more robust connections between the pelvic and axial skeleton (M3 morphotype) are more effective at walking than species with reduced connectivity (M1 morphotype). We predicted that robust connections would facilitate travel per step and increase mass support during movement. We collected high-speed video of walking in seven balitorid species to analyze kinematic variables. The connection between internal anatomy and locomotion on land are revealed herein with digitized video analysis, μCT scans, and in the context of the phylogenetic history of this family of fishes. Our species sampling covered the extremes of previously identified sacral rib morphotypes, M1 and M3. Although we hypothesized the robustness of the sacral rib to have a strong influence on walking performance, there was not a large reduction in walking ability in the species with the least modified rib (M1). Instead, walking kinematics varied between the two balitorid subfamilies with a generally more ‘walk-like’ behavior in the Balitorinae and more ‘swim-like’ behavior in the Homalopteroidinae. The type of terrestrial locomotion displayed in balitorids is unique among living fishes and aids in our understanding of the extent to which a sacral connection facilitates terrestrial walking.

Khon Kaen Agriculture Journal, 49, 6, 1658-1670

Key to the species of Oreoglanis Adapted and modified from Ng & Kottelat, 1999; Ng & Freyhof, 2001; Ng & Rainboth, 2001; Ng, 2004; Chen et al., 2017; Kong et al., 2007; Vidthayanon et al., 2009; Linthoingambi & Vishwanath, 2011; Sinha & Tamang, 2015; Chen et al., 2017. Note: CP = Chao Phraya River basin, MK = Mekong River basin, SW = Salween River basin, ID = Irrawaddy River basin, BP = Brahmaputra River basin, SL = Song Lam River basin. 1. Lower lip notched medially, with entire or weakly laciniate posterior margin; emarginate caudal-fin.................................2 – Lower lip lacking a median notch, with prominent projections along posterior margin; laciniate caudal-fin with principal caudal rays extended.........................................................................16 2. Pectoral-fin not reaching to pelvic-fin origin.........................3 – Pectoral-fin reaching or surpassing pelvic-fin origin.............5 3. Head width 90.2–96.8%HL, post-adipose distance 5.7–8.8%SL and dorsal-fin high 15.4–20.3%SL................ O. sudarai (CP) – Head width 79.3–87.4%HL, post-adipose distance 8.4–14.3%SL and dorsal-fin high 11.4–14.4%SL.........................................4 4. Caudal peduncle length and caudal peduncle depth ratio 4.9–8.4, adipose-fin base 29.1–36.7%SL and head 15.3–17.7%SL............................................................................ O. siamensis (CP) – Caudal peduncle length and caudal peduncle depth ratio 2.1–3.3, adipose-fin base 35.6–39.5%SL and head 18.7–22.9%SL.................................................... O. omkoiense, new species (CP) 5. Branched anal-fin rays 2...................... O. heteropogon (SW) – Branched anal-fin rays 3–6.....................................................6 6. Caudal-fin lunate.....................................................................7 – Caudal-fin emarginate.............................................................8 7. Adipose-fin base length 24.2–29.7%SL, dorsal-fin base length 6.6–9.2%SL, anal-fin base length 2.5–3.6%SL..................................................................................... O. jingdongensis (MK) – Adipose-fin base length 30.7–38.1%SL, dorsal-fin base length 10.9–13.7%SL, anal-fin base length 5.6–7.6%SL...................................................................................... O. suraswadii (MK) 8. Caudal-fin rays 5+5.............................. O. hponkangensis (ID) – Caudal-fin rays 6+6 or 7+8 or 8+7........................................9 9. Posterior margin of maxillary barbel with laciniate projections...................................................... O. setiger (MK) – Posterior margin of maxillary barbel without or with lobulated projections.............................................................................10 10. Caudal peduncle depth 8.0–8.7%SL....... O. macropterus (ID) – Caudal peduncle depth 3.0–6.3%SL.....................................11 11. Small eye 7.7–8.8%HL................................... O. insignis (ID) – Larger eye 9.0–13.7%HL......................................................12 12. Branched anal-fin rays 3.......................................................13 – Branched anal-fin rays 4–6...................................................14 13. Post adipose-fin length 6.5–9.0%SL..... O. immaculatus (SW) – Post adipose-fin length 9.9–10.8%SL....... O. majusculus (BP) 14. Dorsal to adipose-fin distance 21.1%SL................................................................................................... O. pangenensis (BP) – Dorsal to adipose-fin distance 14.4–16.0%SL............................................................................................ O. laciniosus (SW) 15. Maxillary barbel tip pointed........................... O. colurus (CP) – Maxillary barbel tip rounded................................................16 16. Branched dorsal-fin rays 7.................... O. macronemus (MK) – Branched dorsal-fin rays 5–6................................................17 17. Post adipose distance short 2.8–7.0%SL..............................18 – Post adipose distance short more than 7.0%SL...................19 18. Emarginate caudal-fin shape..................... O. tenuicauda (CP) – Lunate caudal-fin shape.................................. O. vicinus (CP) 19. Branched caudal-fin rays 7+7...............................................20 – Branched caudal-fin rays 5–6+6–7, 7–6...............................22 20. Long pre-dorsal length 36.1–37.1%SL........ O. lepturus (MK) – Pre-dorsal length short 30.8–36.5%SL.................................21 21. Anal-fin base length 2.7–3.6%SL, caudal peduncle length 18.7–21.7%SL, head width 18.9–22.4 %SL................................................................................................ O. hypsiurus (MK) – Anal-fin base length 3.6–4.9%SL, caudal peduncle length 21.5–24.0 %SL, head width 16.4–20.8%SL................................................................................................ O. delacouri (MK) 22. Post-adipose distance 9.0–13.8%SL, head depth 9.3–13.5%SL and pre-pelvic length 38.9–44.0%SL.... O. nakasathiani (CP) – Post-adipose distance 6.8–8.9%SL, head depth 7.3–8.0%SL and pre-pelvic length 33.1–9.4%SL.....................................23 23. Branched dorsal-fin rays 6, small eye 7.5–9.8%HL, adipose-fin base length 36.7–47.8%SL, pectoral-fin length 23.0–24.4%SL and head length 18.8–20.7%SL................... O. frenatus (MK) – Branched dorsal-fin rays 5, small eye 10.5–12.1%HL, adipose-fin base length 31.7–36.0%SL, pectoral-fin length 25.3–26.4%SL and head length 21.4–24.7%SL.............................................................................................. O. infulatus (SL), Published as part of Suvarnaraksha, Apinun, 2020, Oreoglanis omkoiense: a new torrent catfish from northern Thailand (Pisces: Siluriformes, Sisoridae), pp. 779-790 in Raffles Bulletin of Zoology 68 on page 780, DOI: 10.26107/RBZ-2020-0089, http://zenodo.org/record/5350342, {"references":["Ng HH & Kottelat M (1999) Oreoglanis hypsiurus, a new species of glyptosternine catfish (Teleostei: Sisoridae). Ichthyological Exploration of Freshwaters, 10: 375 - 380.","Ng HH & Freyhof J (2001) Oreoglanis infulatus, a new species of glyptosternine catfish (Siluriformes, Sisoridae) from central Vietnam. Journal of Fish Biology, 59: 1164 - 1169.","Ng HH & Rainboth WJ (2001) A review of the sisorid catfish genus Oreoglanis (Siluriformes: Sisoridae) with descriptions of four new species. Occasional Papers of the Museum of Zoology University of Michigan, 732: 1 - 34.","Ng HH (2004) Oreoglanis macronemus, a new species of glyptosternine catfish (Teleostei: Siluriformes: Sisoridae) from northern Laos. Raffles Bulletin of Zoology, 52: 209 - 213.","Chen XY, Qin T & Chen ZY (2017) Oreoglanis hponkanensis, a new sisorid catfish from north Myanmar (Actinopterygii, Sisoridae). ZooKeys, 646: 95 - 108.","Kong DP, Chen XY & Yang JX (2007) Two new species of the sisorid Genus Oreoglanis Smith from Yunnan, China (Teleostei: Sisoridae). Environmental Biology of Fishes, 78 (3): 223 - 230.","Vidthayanon C, Saenjundaeng P & Ng HH (2009) Eight new species of the torrent catfish, genus Oreoglanis (Teleostei: Sisoridae) from Thailand. Ichthyological Exploration of Freshwaters, 20 (2): 127 - 156.","Linthoingambi I & Vishwanath W (2011) Oreoglanis majusculus, a new glyptosternine catfish from Arunachal Pradesh, India (Teleostei: Sisoridae). Zootaxa, 2754: 60 - 66.","Sinha B & Tamang L (2015) Oreoglanis pangenensis, a new species of torrent catfish from Arunachal Pradesh, India (Siluriformes: Sisoridae). Ichthyological Exploration of Freshwaters, 25 (4): 331 - 338."]}

Suvarnaraksha, Apinun (2020): Oreoglanis omkoiense: a new torrent catfish from northern Thailand (Pisces: Siluriformes, Sisoridae). Raffles Bulletin of Zoology 68: 779-790, DOI: 10.26107/RBZ-2020-0089

The rheophilic hillstream loaches (Balitoridae) of South and Southeast Asia possess a range of pelvic girdle morphologies, which may be attributed to adaptations for locomotion against rapidly flowing water. Specifically, the connectivity of the pelvic plate (basipterygium) to the vertebral column via a sacral rib, and the relative size and shape of the sacral rib, fall within a spectrum of three discrete morphotypes: long, narrow rib that meets the basipterygium; thicker, slightly curved rib meeting the basipterygium; and robust crested rib interlocking with the basipterygium. Species in this third category with more robust sacral rib connections between the basipterygium and vertebral column are capable of walking out of water with a tetrapod-like lateral-sequence, diagonal-couplet gait. This behavior has not been observed in species lacking direct skeletal connection between the vertebrae and the pelvis. The phylogenetic positions of the morphotypes were visualized by matching the morphological features onto a novel hypothesis of relationships for the family Balitoridae. The morphotypes determined through skeletal morphology were correlated with patterns observed in the pelvic muscle morphology of these fishes. Transitions towards increasingly robust pelvic girdle attachment were coincident with a more anterior origin on the basipterygium and more lateral insertion of the muscles on the fin rays, along with a reduction of the superficial abductors and adductors with more posterior insertions. These modifications are expected to provide a mechanical advantage for generating force against the ground. Inclusion of the enigmatic cave-adapted balitorid Cryptotora thamicola into the most data-rich balitorid phylogeny reveals its closest relatives, providing insight into the origin of the skeletal connection between the axial skeleton and basipterygium.

River-floodplain ecosystems are in delicate balance and are impacted by even minor changes in water availability. In this study, we surveyed fish assemblages and investigated environmental and landscape parameters in a total of 135 floodplain waterbodies (rivers, diversion canals, ponds, irrigation ditches, paddy fields, and wetlands) in the Chao Phraya River Basin in rainy (September 2014) and dry (March 2015) seasons. Factors affecting fish species richness in each type of waterbody were analyzed using generalized linear mixed models. Floodplain area around each surveyed waterbody was a major factor determining fish species richness in rivers, diversion canals, and ponds in the region. The contribution of floodplain area was equivalent to that of hydrology (current velocity, water depth) and water quality (dissolved oxygen, turbidity) in the waterbodies. The population of juvenile fishes was increased in temporarily connected floodplain waterbodies to main rivers compared with isolated waterbodies, and fluvial and lacustrine fishes were observed in the temporary inundated floodplain waterbodies during the rainy season. The high dependence of fish species richness on floodplain area in the region appeared to be a result of the use of inundated floodplains by fish species to forage and breed. Our results highlight the impact of flood control measures that reduces floodplain area. These measures must be reviewed to ensure the conservation of fish biodiversity in the Chao Phraya River Basin, one of the world’s most threatened floodplain systems.

Summary The riverine species, Henicorhynchus siamensis (Sauvage 1881), is an important source of protein and an economical fish for the rural population of inland Indochina. Investigated in the present study were the reproductive feeding aspects and growth of H. siamensis living in a lake system. The gonadosomatic index peaked in August, which was delayed compared to river fish, and individuals took 1.5 years to attain the length of 50% maturity (about 200 mm). Stomach contents were dominated by phytoplankton and showed considerable seasonal variation. Asymptotic length of H. siamensis was 264.2 mm, with a 0.75 year )1 growth coefficient and slower growth during the winter. The role of the flood pulse as a major influence on the life history of the fish is also discussed.

Fishes have adapted a number of different behaviors to move out of the water, but none have been described as being able to walk on land with a tetrapod-like gait. Here we show that the blind cavefish Cryptotora thamicola walks and climbs waterfalls with a salamander-like diagonal-couplets lateral sequence gait and has evolved a robust pelvic girdle that shares morphological features associated with terrestrial vertebrates. In all other fishes, the pelvic bones are suspended in a muscular sling or loosely attached to the pectoral girdle anteriorly. In contrast, the pelvic girdle of Cryptotora is a large, broad puboischiadic plate that is joined to the iliac process of a hypertrophied sacral rib; fusion of these bones in tetrapods creates an acetabulum. The vertebral column in the sacral area has large anterior and posterior zygapophyses, transverse processes and broad neural spines, all of which are associated with terrestrial organisms. The diagonal-couplet lateral sequence gait was accomplished by rotation of the pectoral and pelvic girdles creating a standing wave of the axial body. These findings are significant because they represent the first example of behavioural and morphological adaptation in an extant fish that converges on the tetrapodal walking behaviour and morphology.

Both hydropower dams and global warming pose threats to freshwater fish diversity. While the extent of global warming may be reduced by a shift towards energy generation by large dams in order to reduce fossil-fuel use, such dams profoundly modify riverine habitats. Furthermore, the threats posed by dams and global warming will interact: for example, dams constrain range adjustments by fishes that might compensate for warming temperatures. Evaluation of their combined or synergistic effects is thus essential for adequate assessment of the consequences of planned water-resource developments. We made projections of the responses of 363 fish species within the Indo-Burma global biodiversity hotspot to the separate and joint impacts of dams and global warming. The hotspot encompasses the Lower Mekong Basin, which is the world's largest freshwater capture fishery. Projections for 81 dam-building scenarios revealed progressive impacts upon projected species richness, habitable area, and the proportion of threatened species as generating capacity increased. Projections from 126 global-warming scenarios included a rise in species richness, a reduction in habitable area, and an increase in the proportion of threatened species; however, there was substantial variation in the extent of these changes among warming projections. Projections from scenarios that combined the effects of dams and global warming were derived either by simply adding the two threats, or by combining them in a synergistic manner that took account of the likelihood that habitat shifts under global warming would be constrained by river fragmentation. Impacts on fish diversity under the synergistic projections were 10-20% higher than those attributable to additive scenarios, and were exacerbated as generating capacity increased-particularly if CO2 emissions remained high. The impacts of dams, especially those on river mainstreams, are likely to be greater, more predictable and more immediately pressing for fishes than the consequences of global warming. Limits upon dam construction should therefore be a priority action for conserving fish biodiversity in the Indo-Burma hotspot. This would minimize synergistic impacts attributable to dams plus global warming, and help ensure the continued provision of ecosystem services represented by the Lower Mekong fishery.

Schistura sirindhornae, a new species of nemacheilid, is described from the Nan River basin in northern Thailand. It is distinguished from all other species of Schistura in having overlapping scales on the entire body similar to scales of balitorids, transparent scales on the belly and thorax, a lateral-line canal that is similar to that of most cyprinids and balitorids in being present across the entire lateral-line surface of the scale instead of being represented only by a pore. It also has a unique color pattern of irregular brown bars on the back and side of the faint yellow-orange body, a bright triangular orange mark on the occiput, an orange crown-shaped mark between the eyes, an uninterrupted black mark along the base of the dorsal fin, a crescent-shaped bar on the base of the caudal fin, and bright iridescent orange areas on the upper and lower extremities of the caudal-fin base. Schistura sirindhornae is known only from the upper Nan River drainage, Nan Province, Thailand.

Physoschistura chulabhornae, new species (Figs. 1, 2) Holotype. MARNM 3998, 6 May 2008, Huay Maetalanoi, Ban Maetala, T. Maedaed, Maechaem District, Chiangmai, near a village, 18 ° 55 ' 35.43 ''N, 098° 22 ' 45.63 ''E; tributary of Ping River, northern Chaophraya River basin, Maechaem District, Chiangmai Province, coll. A. Suvarnaraksha, R. Wattanasiriserekul and colleagues. Paratypes. MARNM 3999, 36 ex., 26.6–36.5 mm SL, 34.8–47.6 mm TL, NIFI: 0 4836, 3 ex., 31.0– 33.8 mm SL, 38.5–42.4 mm TL, and UF 185354, 3 ex., 28.4–33.2 mm SL, 38.0– 43.4 mm TL; same data as holotype. Diagnosis. This new species can be distinguished from other members of Physoschistura by the following combination of characters: incomplete lateral line with 62–83 pores, reaching between anal-fin origin and anal-fin tip; no axillary lobe on pelvic-fin base; male with hammer head-shaped suborbital flap (Fig. 1). Description. Morphometric measurements, proportions and meristic counts of the holotype and 42 paratypes are presented in Tables 1 –3. A relatively small to medium-sized species compared to other species of Physoschistura with a moderately elongated body; body sub-cylindrical anteriorly in cross section, compressed posteriorly; dorsal profile slightly arched, ventral profile straight throughout; snout obtuse to pointed; strongly arched mouth, 1.5–1.7 ± 0.08 times wider than long with medially interrupted lower lip forming two lateral broadly triangular pads with deep furrows, pads 1.5 ± 0.07 times wider than long (Fig. 3); lips thin, upper lip with small incision in middle, lower lip with deep median interruption; anterior nostril in front of flap-like tube with pointed tip; eye small, 4.0– 4.8 times in HL (mean 4.3 ± 0.2), eye diameter 3.0– 3.8 times in interorbital space. Inner rostral barbel longer than outer rostral barbel and maxillary barbel, extending to middle of eye, longer than snout (0.7– 0.96 ± 0.06); outer rostral barbel not reaching to anterior margin of eye; maxillary barbel reaching to posterior margin of eye. Processus dentiformis present, not prominent. Free posterior chamber of air bladder well formed, not encapsulated, and slightly oval (Fig. 4). Morphometric characters Holotype Paratypes (n = 42) Range mean SD Standard length (mm) 30.49 25.82–39.98 31.16 2.2 % SL Total length 126.2 123.3–133.7 128.6 2.3 Fork length 121.9 117.5–126.9 122.4 2.2 Prepectoral-fin length 25.0 21.8–28.7 24.2 1.5 Pectoral-fin length 21.7 20.8–25.3 23.2 1.1 Predorsal-fin length 50.2 46.8–52.7 49.4 1.4 Preanal-fin length 76.2 71.5–79.8 75.9 1.7 Prepelvic-fin length 48.5 47.0– 53.9 49.9 1.6 Pelvic-fin length 21.3 18.4–23.5 20.3 1.1 Pelvic to vent distance 21.3 20.5–27.1 23.0 1.5 Dorsal-fin base length 17.7 15.3–22.9 17.9 1.5 Dorsal-fin length 23.1 19.5–26.7 23.6 1.8 Anal-fin base length 9.4 7.1–13.9 11.1 1.6 Anal-fin length 19.9 16.8–24.7 20.5 1.6 Body depth at dorsal-fin origin 17.8 15.6–23.2 19.6 1.8 Body width at dorsal-fin origin 10.1 8.6–18.8 12.8 2.2 Body depth at anal-fin origin 13.6 13.0– 16.3 14.1 0.8 Body width at anal-fin origin 6.2 5.3–8.5 7.0 0.8 Caudal-peduncle length 12.4 10.7 –15.0 12.4 1.0 Caudal-peduncle depth 10.7 8.2–11.9 10.7 0.6 Caudal-fin length 26.2 23.3–33.7 29.2 2.3 Head length 22.3 22.3–26.6 24.1 1.2 Dorsal head length 18.3 18.2–23.4 20.6 1.2 Head width 10.7 10.0– 12.7 11.3 0.6 Head depth at occiput 13.2 12.7–15.2 13.8 0.6 % HL Dorsal head length 82.0 81.2–86.1 84.8 1.4 Head width 48.0 42.6–48.9 44.9 1.7 Head depth at occiput 56.4 52.3–56.4 55.1 1.0 ......continued on the next page Morphometric characters Holotype Paratypes (n = 42) Range mean SD Eye diameter 25.8 22.5 –26.0 24.4 1.0 Interorbital length 29.9 28.0– 31.9 29.9 0.7 Inter-nostril distance 20.9 19.0– 21.7 20.4 0.6 Snout length 35.1 33.2–35.9 35.0 0.7 Mouth width 28.7 25.9–29.9 28.4 0.9 Mouth length 18.6 16.3–19.1 17.6 0.7 Rostral barbel I length 29.5 27.3–29.9 29.2 0.7 Rostral barbel II length 42.0 39.1 –43.0 41.4 1.0 Maxillary-barbel length 35.2 34.2–36.9 35.1 0.7 Ratios Mouth width/mouth length 1.5 1.5–1.7 1.6 0.08 Snout/maxillary-barbel length 1.0 0.9 –1.0 1.0 0.03 Head length/eye diameter 3.9 3.9–4.4 4.1 0.2 Eye diameter/Interorbital space 0.9 0.7–0.9 0.8 0.04 Lateral head length/pectoral-fin length 1.0 0.9–1.2 1.0 0.06 Caudal-peduncle depth/caudal-peduncle length 1.2 1.0– 1.4 1.2 0.12 Standard length/pelvic-fin length 4.7 3.9–4.8 4.3 0.06 males 4.7 4.3 –5.0 4.7 0.2 females - 4.6–5.4 5.0 0.2 Body depth/body width at dorsal-fin origin 1.8 0.9–2.1 1.5 0.2 males 1.8 1.4–2.1 1.8 0.2 females - 0.9–1.6 1.5 0.1 Pelvic-fin length/vent to anus distance 1.0 0.8–1.1 0.9 0.1 males 1.0 0.78 –1.0 0.95 0.07 females - 0.78–0.96 0.87 0.05 Body depth at dorsal fin/body depth at anal fin 1.3 1.2–1.6 1.4 0.1 males 1.3 1.2–1.4 1.3 0.1 females - 1.3–1.6 1.4 0.1 Body covered with embedded minute scales, except belly naked between pectoral fin bases. Incomplete lateral line reaching between anal-fin origin and tip of anal fin with 62–83 pores. Cephalic lateral-line system with 7 supraorbital, 4 + 8–10 infraorbital, 7 preoperculo-mandibular, and 3 supratemporal pores. Unculi present on lips, barbels, and pectoral-fin rays. Dorsal fin half-way between tip of snout and caudal-fin base; dorsal fin with 4 simple and 8 ½ branched rays, distal margin slightly convex. Pectoral fin rounded, the length 1.04 ± 0.06 times lateral head length, origin near surface of breast, with 1 simple and 11 branched rays, reaching two-thirds distance to pelvic-fin origin in female, but close to pelvic-fin origin in male. Pelvic-fin origin slightly behind dorsal-fin origin, at vertical from 1 st or 2 nd branched dorsal-fin rays, with 1 simple and 7 branched rays. Distal margin of pelvic fin not reaching vent in female, nearly reaching vent in male when adpressed. Pelvic-fin length 20.3 ± 1.1 % SL; fin not extending beyond anus, except reaching anus in some males (0.96 ± 0.04 % HL). Anal fin not reaching base of caudal fin, with 3 simple rays and 5 ½ branched rays; no adipose crest on caudal peduncle. Anus is much nearer to anal fin than to caudal-fin base. Intestine curved toward lower part of stomach (Fig. 5). Caudal fin with 8– 9 upper and 8 lower branched rays, forked, upper lobe slightly shorter than lower lobe, both lobes with rounded tips. Caudal peduncle 1.2 ± 0.1 times longer than deep. Largest recorded size: 36.5 mm SL (47.6 mm TL) female (paratype, MARNM 3999 / 14). Colour in life. Body translucent and light yellowish-brown. Eight- 10 dark olivaceous blotches on side of body, 8–10 dark saddles on back not extending to belly; large males have fewer blotches on side of body and faint dorsal saddles; iridescent stripes on belly and lower half of body from pectoral fin to anus (Fig. 2). Lower lip without black mark on each side of median interruption (Fig. 3 a). Dorsal and dorso-lateral portion of head with few irregular dark spots. Basicaudal bar fragmented into small blotch on upper caudal-fin base, vertical olivaceous blotch on lower caudal-fin base; thin, horizontally oriented, faint Vs on median part of caudal fin. Black spot at base of simple ray of dorsal fin. Pectoral, pelvic and anal fins hyaline. Colour in preservative. Body creamy white; head and snout with few, scattered dark brown spots; basicaudal bar dissociated into two blotches, one blotch at upper caudal-fin base, larger vertical blotch on lower caudal fin base. Sexual dimorphism. Male with hammer head-shaped suborbital flap (Fig. 3 b), and stiff first branched pectoral-fin ray with numerous rows of unculi on upper surface. Pectoral-fin length slightly longer or same length as head (vs. shorter in female); tip of pectoral fin length reaches pelvic-fin origin (vs. not reaching in female). Some females have a small groove in same position as suborbital flab in male. Fewer lateral blotches in large male, changing to longitudinal stripe along lateral line. Male has more slender body; body depth/body width at dorsal-fin origin 1.4–2.1 in male vs. 0.9–1.6 in female (Table 1). Pelvic-fin/SL 4.3 –5.0 in males vs. 4.6–5.4 in females. One female (MARNM 3999 / 14 30.0 mm SL) contained 260 large eggs (0.6 mm diameter ). Habitat. Specimens were collected from the Huay Maetalanoi, Ban Maetala, T. Maedaed, Maechaem District, Chiangmai (Fig. 6). The stream has a mixed sand, gravel, pebble, silt, mud and rock bottom, with clear running water (Fig. 7). Elevation at the type locality is 764 m above mean sea level, and annual rainfall is over 1450 mm. The surrounding landscape has semi-evergreen forest, plantations, and agricultural crops (mainly corn, cabbage and tomato). Water temperature was 17 °C, air temperature 20.5 °C, pH 7.7, DO 6.5 mg /l, and conductivity 20 ΜS. Stream width averaged 4 meters, and water depth 40–60 cm. All specimens were collected during the daylight. The holotype and paratypes were caught by electro-fishing. Other species collected at the type locality were: Nemacheilidae: Schistura breviceps, Schistura maejotigrina; Sisoridae: Oreoglanis siamensis; Cyprinidae: Devario sp., Scaphiodonichthys burmanicus, Opsarius pulchellus, Garra cambodgiensis, Puntius brevis, Puntius stoliczkanus; Synbranchidae: Monopterus albus; and Channidae: Channa gachua. Distribution. This species has only been collected at the type locality in the Maechaem River basin (Fig. 7), a tributary of Ping River, northern Chaophraya River Basin, Maechaem District, Chiangmai Province, Thailand. Etymology. The species epithet honours Her Royal Highness Princess Chulabhorn for her valuable scientific works., Published as part of Suvarnaraksha, Apinun, 2013, A new species of Physoschistura (Pisces: Nemacheilidae) from northern Thailand, pp. 236-248 in Zootaxa 3736 (3) on pages 237-244, DOI: 10.11646/zootaxa.3736.3.2, http://zenodo.org/record/215704

Suvarnaraksha, Apinun (2013): A new species of Physoschistura (Pisces: Nemacheilidae) from northern Thailand. Zootaxa 3736 (3): 236-248, DOI: http://dx.doi.org/10.11646/zootaxa.3736.3.2

Physoschistura chulabhornae, new species, is described from Maechaem River, a tributary of Ping River, upper Chaophraya River drainage, Chiangmai province, Thailand. It is distinguished from all other known species of Physoschistura in having an incomplete lateral line reaching at least to the origin of the anal fin with 62-83 lateral-line canal pores, the dorsal-fin origin slightly in front of the pelvic-fin origin, no axillary pelvic lobe, and a suborbital flap in the shape of a hammer head in the male.

Schistura maejotigrina, new species, is described from Maechaem River, a tributary of Ping River, in the upper Chao Phra-ya River drainage, Chiang Mai Province, Thailand. It is distinguished from all other species of Schistura in having 21–24dark tiger-stripe black bars on the side of the body and 6½–7½ branched dorsal soft rays. The species is medium-sized,reaching 53.0 mm SL (69.6 mm TL), and is known only from the Maechaem River system, Ping River drainage, northernChao Phraya River basin, Chiang Mai Province, Thailand. It lives in fast running, clear water over a substrate of mixed gravel, small stone and sand.