Friday, February 13, 2026

[Ichthyology • 2026] Magnischistura khaokrajom • A New Genus and Species of Loach (Cypriniformes: Nemacheilidae) from the Pachi River drainage in Western Thailand


Magnischistura khaokrajom  Page, Pawangkhanant & Cagle,

in Page, Pawangkhant, Tangjitjaroen, Cagle, Williams et Randall, 2026. 
Krajom Mountain Stream Loach | ปลาค้อปิศาจ ||  DOI: doi.org/10.11646/zootaxa.5757.6.7 
 
Abstract
Magnischistura khaokrajom, new genus and species, is described from a small tributary of the Pachi River in the Suan Phueng region of the Tenasserim Hills in western Thailand. Magnischistura shares with several recently described genera of nemacheilids a globulous suborbital flap with tubercles at its extremity and a highly modified pectoral fin on mature males, but molecular data failed to support a close relationship to any of them. Morphologically, the new genus is distinguished by the presence of a suborbital flap in the female. The highly modified pectoral fin of males is hypothesized to facilitate juxtaposition with a female during spawning.

Taxonomy, Phylogeny, Southeast Asia

(A-C) Magnischistura khaokrajom.
(A) UF 248549, paratype, 74.1 mm SL, female, live, (B) UF 248549, paratype, 68.4 mm SL male, live, (C) THNHM-F023975, holotype, 74.0 mm SL male, preserved,
(D) Mustura maepaiensis, UF 188267, 42.3 mm SL, live.

Magnischistura, Page, Pawangkhanant & Cagle, new genus 

Diagnosis. Magnischistura is distinguished from all other genera of Nemacheilidae by the combination of: (a) in adult males, a pectoral fin that is rigid, curved upward, and has a thick tuberculated pad on the dorsal surface and epidermal flanges on the narrow membranes (Figure 4B); a large, vertically oriented, globulous suborbital flap with tubercles on its underside and distal edge (Figure 4A); (b) in adult females, a pectoral fin with a thick pad on the dorsal surface and epidermal flanges on the membranes (Figure 4D), and a small suborbital flap (Figure 4C); and (c) large size—to at least 98 mm SL.

Etymology. Magni- refers to the large size of the type species relative to most species of nemacheilids in Indochina, and Schistura McClelland 1838 is a widespread genus of nemacheilids. Gender feminine.


Magnischistura khaokrajom, Page, Pawangkhanant, and Cagle, new species
Krajom Mountain Stream Loach
ปลาค้อปิศาจ [Pla Kor Pi Saad]

Etymology. Khaokrajom, meaning Krajom Mountain in Thai, where this species lives.

 
Lawrence M. PAGE, Parinya PAWANGKHANT, Weerapongse TANGJITJAROEN, David K. CAGLE, Basil R. WILLIAMS and Zachary S. RANDALL. 2026. Magnischistura khaokrajom, A New Genus and Species of Loach (Cypriniformes: Nemacheilidae) from the Pachi River drainage in Western Thailand. Zootaxa. 5757(6); 583-599. DOI: doi.org/10.11646/zootaxa.5757.6.7 [2026-02-11]