Beaufortia kweichowensis kweichowensis

Beaufortia kweichowensis kweichowensis (Fang, 1931)

In this small essay I basically follow YUE et al (2000) in taxonomy regard for the taxon differentiation into subspecies, for general classification I follow ESCHMEYER (2006). I treat Balitoridae as valid family within the order Cypriniformes, deviating from YUE et al, who place the genus Beaufortia within the subfamily Gastromyzoninae and in the family Homalopteridae. Further on I accept the two subspecies B. kw. kweichowensis and B. kw. gracilicauda as valid in accordance with YUE et al. I know, my assumptions are inconsistent, but I consider them right for the time being. This taxonomic arrangement composes the tree below:

Differentiation to Beaufortia leveretti and into subspecies

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Taxonomy

The habitus and coloration of B. kw. kweichowensis and B. leveretti are rather similar. The coloration ist highly variable and ranges from pale beige over intense brown to greyish tones. Both species can not be distinguished by their appearances. As far as I know the only key to the species of the genus Beaufortia is printed in YUE et al. Although this paper has been issued in 2000, it does not contain the species differentiation of Beaufortia intermedia, which has been described by Tang and Wang in 1997 and seems to be a valid taxon. Further drawbacks of the key are the somewhat incomplete information about meristic and morphometric data and confusing, misleading species distribution, which is for certain species simply too limited. Their distributional range is much wider. However, I based on this key to the species developing a special key for quick and easy identifying B. leveretti and the subspecies of B. kweichowensis. My key should be understandable and usable for non-ichthyologists, hobbyists and aquarists – for all those of us, who do not want to disembowel their flat loaches.

In the specific, related literature and internet sources there have been no characteristics for sex differentiation of B. kw. kweichowensis defined. I have never bred these flat loaches so far, but some behavioral facts made me to have a closer look at the fishes. Some fishes are much more active than others. Some are looking for food and defending territories all day long. My alpha specimen – identified clearly as a male – achieved sustained success in defending its territory from others. His territory was the best feeding ground located directly below the feeding scuttle of the fish tank. All other Beaufortia, especially other males were aggressively chased off. Other males showed the identical behavior within the confines of their territories. All the usable surfaces in the entire tank were allocated among the males. They prefer smooth surfaces like the tank’s glass panes. While males are chasing off conspecific males, they don not do so with the females. After a period of starvation it might be possible that males chase off females.

Sex differentiation

Females are often congregating in areas with a high oxygen level or in areas, which are inaccessible due to water plants, wood etc... My females preferred the rear glass pane and the pane above the air diffuser. Here they really get clustered. Approaching males behaved gentle and did not case them off. They were trying to approach closely. Sometimes a pair hung on a pane for hours – as long as it took the males started chasing each other again.

A close up look to the fishes revealed morphological sexual characteristics. Sucking on the panes you can see a difference in the shape of the head. Both genders possess rather fleshy cheeks, which are used to the seal and adjust the vacuum on the ventral side. The sex differentiation is a different angle between the cheeks in the transition to the pelvic fins. Males almost have a rectangular shoulder, therefore males affect quite brawny and muscular. In males the head seems to be comparatively longer than in females. Females possess an broad angle, which is over 90 degrees. In some females there is no real interruption, the cheek just transit into the pectoral fin (angle almost 180 degrees). They look short snouted and much more beefy and broader in body width than the males.

Distributional range

B. kw. kweichowensis is spread over the torrents of the Xijiang River (West River), which belongs to the Zhujiang River system, notoriously famous as the Pearl River, which empties trough the Pearl River delta in the South Chinese Sea. The distributional range is wide and lies in the chinese provinces Guizhou (type locality), Guangxi and Guangdong. More narrowly limited is the distributional range of the other subspecies B. kw. gracilicauda. It is found in the Beiiang (North River) and Dongjiang (East River); both are also tributaries to the Zhujiang River. The range is limited to Guangdong province.

PS: Deviating from the general assumption in the bulk of the western literature the distribution of Beaufortia leveretti is not limited to Hainan Island only. It is not an endemic species, but has a huge range from northern Vietnam in the south to the Chinese province Yunnan in the north.

Marco Endruweit, September 2006, updated May 2008, updated October 2008 (added 3 new species described by Nguyen in 2005), updated 2008-12-9 (text improved and added 3 more species described by MAI in 1978), updated 2009-08-26 (added Beaufortia niulanensis Chen, Huang & Yang, 2009 sp. nov.)

 

Some examples; BAENSCH & RIEHL (1996) undoubtfully show a male (page 143), HUANG, CHENG & LE (1988) also picture a brawny, well developed male (#135). For further examples please check my photos link.

Beaufortia kw. kweichowensis - male
Beaufortia kw. kweichowensis - female

This picture undoubtfully shows a female Beaufortia kw. kweichowensis

This is a quite strong male of Beaufortia kw. kweichowensis

Another involved species in the mix-up is Beaufortia daon from the Nam Ma basin in the Laotian province Houaphan and the Red River in northern Vietnam (KOTTELAT, 2001a, 2001b). There is very few known about this species, but it belongs certainly in the genus Beaufortia, since it possesses continuous ventral fins, which is a characteristic for Beaufortia. The appearance and coloration resemble the other two species. According to the initial description Beaufortia daon did not have a concave in the mandibular (lower jaw). The transition of the lower lip is straight (over the normal radius of the lip). The anus is clearly visible.