Tuesday, October 24, 2017

[Ichthyology • 2017] Channa shingon • A New Dwarf Snakehead (Perciformes: Channidae) from western Yunnan


Channa shingon
 Endruweit, 2017 

 Vertebrate Zoology. 67(2) 

Abstract

 Channa shingon, new species, is described from small mountainous rivulets associated with the Irrawaddy drainage in western Yunnan Province, China. Its maximum SL of about 100 mm makes it the smallest pelvic-fin bearing dwarf snakehead. Further specific characters are lateral head length 27–30 % SL; interorbital width 33 –35 % HL; 25–27 anal-fin rays; 44–45 lateral-line scales; 4 –5 scale rows between dorsal-fin origin and lateral line; 8 –9 scale rows between lateral line and anal-fin origin; 1 mandibular scale; 43–44 vertebrae; inferomesial process of parasphenoid very shallow and straight; dorsal profile conspicuously bulging in front of dorsal fin; juveniles without ocellus-like mark on posterior part of dorsal fin; and a pectoral-fin pattern of 3 – 4 broad gray to black bands alternating with cream to white interspaces, bands increasingly wide towards distal edge of the fin, interspaces equally wide as bands or narrower.

Key words: Channa; new species; Irrawaddy; Salween; taxonomy

Fig. 1. Channa shingon; Erganya, Yingjiang; Jieyanghe River: a, KIZ 2014005982, 89.7 mm SL, holotype; b, KIZ 2014005980, 90.2 mm SL, paratype, reversed; c, KIZ 2014005971, 89.4 mm SL; Cangyuan; Nangunhe River. 
  
Channa shingon, new species

Diagnosis. Channa shingon is distinguished from other members of the C. gachua-complex (Britz, 2008) by having a lateral head length 27–30 % SL; interorbital width 33 – 35 % HL; 25–27 [26] anal-fin rays; 44– 45 [45] lateral-line scales; 4 –5 [4] transverse scales to dorsal-fin origin and 8–9 [8] to anal-fin origin; 1 mandibular scale, 43 –44 [44] vertebrae; inferomesial process of parasphenoid very shallow and straight; dorsal profile conspicuously bulging in front of dorsal fin; pelvic fin present; juveniles without ocellus-like mark on posterior part of dorsal fin; a pectoral-fin pattern of 3–4 broad gray to black bands alternating with cream to white interspaces, width of bands increasing towards distal edge of the fin, interspaces equally wide as bands or narrower; and a maximum standard length of about 100 mm.

Distribution. Known from the Irrawaddy and Salween drainages in Dehong and Lincang prefectures, Yunnan, China; expected to occur in the same drainages in Myanmar.

 Ecology. Channa shingon prefers weedy, stagnant water sections of small mountainous rivulets. These rivulets are often redirected to irrigate rice paddies. At the type locality, the ankle-deep water was clear, with a pH of 5.9, a conductivity of 20 µS/cm, and a temperature of 12 ºC in the afternoon. The lower reaches of these rivulets, shortly before the influx into a larger stream are usually also inhabited by Misgurnus anguillicaudatus and juveniles of C. harcourtbutleri. Another habitat of C. shingon, the Mengnaihe River upstream of Xima at an elevation of 1730 m, had a water temperature of just 8 ºC in the morning (pH 6.7; 20 µS/cm); some backwaters had a thin layer of ice after a chilly night. Vast areas of C. shingon’s habitats are ephemeral and desiccate during droughts.

Etymology. The specific epithet is derived from a character in Burmese spiritualism. Shingon, also referred to as Lady Humpback, is one of the 37 officially recognized spirits (nats) in Myanmar; an allusion to the species’ humpbacked appearance; a noun in apposition.


Marco Endruweit. 2017. Description of A New Dwarf Snakehead (Perciformes: Channidae) from western Yunnan.  Vertebrate Zoology. 67(2); 173-178.