Bagrichthys

Taxobox
name = "Bagrichthys"
regnum = Animalia
phylum = Chordata
classis = Actinopterygii
ordo = Siluriformes
familia = Bagridae
genus = "Bagrichthys"
genus_authority = Bleeker, 1857
subdivision_ranks = Binomial name
subdivision =
"Bagrichthys hypselopterus"
(Bleeker, 1852)
"Bagrichthys macracanthus"
(Bleeker, 1854)
"Bagrichthys. macropterus"
(Bleeker, 1853)
"Bagrichthys majusculus"
Ng, 2002
"Bagrichthys micranodus"
Roberts, 1989
"Bagrichthys obscurus"
Ng, 1999
"Bagrichthys vaillantii"
(Popta, 1906)


synonyms = "Pseudobagrichthys"
Bleeker, 1862

"Bagrichthys" is a genus of catfishes (order Siluriformes) of the family Bagridae. It contains seven species, "B. hypselopterus", "B. macracanthus", "B. macropterus", "B. majusculus", "B. micranodus", "B. obscurus", and "B. vaillantii".cite journal|url=http://silurus.acnatsci.org/ACSI/library/biblios/2007_Ferraris_Catfish_Checklist.pdf|title=Checklist of catfishes, recent and fossil (Osteichthyes: Siluriformes), and catalogue of siluriform primary types|first=Carl J., Jr.|last=Ferraris|journal=Zootaxa|volume=1418|pages=1–628|year=2007|format=PDF]

Taxonomy

This genus is most closely related to the genus "Bagroides". In turn, these two genera are most closely related to "Leiocassis". The genus can be split into two lineages. "B. hypselopterus", "B. macracanthus", "B. majusculus", and "B. vaillantii" have long dorsal fins with 18 or more serrations in adults, while "B. macropterus", "B. micranodus", and "B. obscurus" have short dorsal fins with 15 or fewer serrations in adults. The first lineage is more derived, while the second lineage is more basal.

Distribution

"B. hypselopterus" is found in Sumatra and Borneo, "B. macracanthus" in the Mekong and Chao Phraya River basins and Sundaland, "B. macropterus" in Sumatra, "B. majusculus" in the Mekong and Chao Phraya River basins, "B. micranodus" in the Kapuas River of Western Borneo, "B. obscurus" in the Mekong, Bang Pakong, and Chao Phraya River basins, and "B. vaillantii" in the Mahakam River basin of eastern Borneo.

Description

"Bagrichthys" catfishes are highly specialized. Fish of this genus are characterised by their elongate and laterally compressed caudal peduncle, the dorsally-directed serrations on the posterior edge of the dorsal fin spine, gill membranes united at the isthmus, and a long adipose fin without a free posterior margin. These fish can grow between about 20–40 centimetres (8–16 in) in length.FishBase species|genus=Bagrichthys|species=hypselopterus|year=2007|month=June] FishBase species|genus=Bagrichthys|species=macracanthus|year=2007|month=June] FishBase species|genus=Bagrichthys|species=macropterus|year=2007|month=June] FishBase species|genus=Bagrichthys|species=micranodus|year=2007|month=June] The coloration of "Bagrichthys" species varies from tan to black; however, coloration can vary between individuals based on environmental conditions. These species have a small narrow mouth, moderately elongate convoluted intestines, and greatly reduced oral dentition.

Many of the "Bagrichthys" species appear rather similar. "B. obscurus" and "B. majusculus" were both identified after it was recognized that they were different species from "B. macropterus" and "B. macracanthus", respectively, which these two species had previously been misidentified as.cite journal|url=http://www-personal.umich.edu/~heokheen/ng_2002.pdf|title="Bagrichthys majusculus", a new catfish from Indochina (Teleostei, Bagridae)|first=Heok Hee|last=Ng|journal=Folia Zool.|volume=51|issue=1|pages=49–54|year=2002|format=PDF]

The male can be distinguished from the female. The male possess a genital papilla just before the anal fin, while the female does not. Also, in "B. majusculus", "B. obscurus", and "B. vaillantii" the nasal and maxillary barbels of males are more than twice as long as barbels of females; this may hold true for the whole genus.cite web|url=http://www.planetcatfish.com/shanesworld/shanesworld.php?article_id=224|title=Notes on the Lancers of the genus Bagrichthys|last=Ng|first=Heok Hee|coauthors=Linder, Shane|accessdate=2007-06-30]

Ecology

"Bagrichthys" species live in large muddy rivers throughout Southeast Asia.cite journal|url=http://www.scielo.sa.cr/scielo.php?script=sci_arttext&pid=S0034-77441999000300028&lng=es&nrm=iso|title="Bagrichthys obscurus", a new species of bagrid catfish from Indochina (Teleostei: Bagridae)|first=Heok Hee|last=Ng|journal=Revista de Biología Tropical|volume=47|issue=3|year=1999] However, juveniles may be found in smaller streams and flooded forests during the rainy season. The normal habitats of "Bagrichthys" species are large, slow-flowing rivers, generally acidic(pH 5–6) and with turbid water and a muddy substrate.

"Bagrichthys" species are reported to feed on small fishes, benthic invertebrates, and large amounts of plant detritus. "B. hypselopterus" consumes large amounts of silt as it targets chironomid larvae and pupae. "B. macropterus" may be molluscivorous as their guts have been found to contain large quantities of "Rivomarginella" gastropod shells.

These species spawn in the beginning of the rainy season and utilize flooded forests along the river edge. Juveniles appear in August.

In the aquarium

"B. macracanthus", the black lancer, is the only species of this genus that is traded for the aquarium hobby. When these fish are first imported, they are often young and in bad condition. It has been recommended to acclimate these fish at a high temperature (about 29°C or 85°F).cite web|url=http://www.planetcatfish.com/cotm/cotm.php?article_id=99|title=PlanetCatfish::Catfish of the Month::January 2001|date=2006-06-07|accessdate=2007-06-11] Though nocturnal, this species may be trained to eat in the light; it may even be trained to feed from the owner's hand. These fish tend to be territorial among their own kinds though this behavior can be reduced by placing a male with multiple females. This species is quite adaptable with ph and DH and will thrive as long as extremes are avoided.cite journal|url=http://www.catfishstudygroup.org/pdf/catfishes_of_asia2.pdf|title=The Catfishes of Asia Family Bagridae part two|last=Linder|first=R. Shane|journal=Cat Chat|volume=1|issue=2|date=June 2000|format=PDF]

References