Rheocles

Taxobox
name = "Rheocles"


image_width = 250px
image_caption =
regnum = Animalia
phylum = Chordata
classis = Actinopterygii
ordo = Atheriniformes
familia = Bedotiidae
genus = "Rheocles"
genus_authority = Jordan and Hubbs in Jordan, 1919
subdivision_ranks = Speciescite journal|url=http://research.amnh.org/scicomp/pdfs/Sparks_Smith2004b.pdf|title=Phylogeny and biogeography of the Malagasy and Australasian rainbowfishes (Teleostei: Melanotaenioidei): Gondwanan vicariance and evolution in freshwater|first=John S.|last=Sparks|coauthors=Smith, W. Leo|journal=Molecular Phylogenetics and Evolution|volume=33|year=2004|pages=719–734|format=PDF|doi=10.1016/j.ympev.2004.07.002]
subdivision = "R. alaotrensis"
"R. derhami"
"R. lateralis"
"R. pellegrini"
"R. sikorae"
"R. vatosoa"
"R. wrightae"
synonyms =
*"Rheocloides"
Nichols and La Monte, 1931

"Rheocles" is a genus of Bedotiidae. "Rheocles" has a restricted distribution, being found only in certain forested freshwater habitats in the central and eastern highlands of Madagascar.cite journal|url=http://digitallibrary.amnh.org/dspace/bitstream/2246/4996/1/N3031.pdf|title=Description of a New Species of "Rheocles" (Atherinomorpha, Bedotiidae) from the Nosivolo Tributary, Mangoro River, Eastern Malagasy Republic|first=Melanie L. J.|last=Stiassny|coauthors=Reinthal, Peter N.|issue=3301|date=February 24, 1992|pages=1–8|format=PDF] The genus appears to feed almost exclusively on allochthonous material, primarily insects falling onto the water surface.

Taxonomy

In a 1990 study, this genus is monophyletic.cite journal|url=http://digitallibrary.amnh.org/dspace/bitstream/2246/5063/1/N2979.pdf|title=Notes on the Anatomy and Relationships of the Bedotiid Fishes of Madagascar, with a Taxonomic Revision of the Genus "Rheocles" (Atherinomorpha: Bedotiidae)|first=Melanie L. J.|last=Stiassny|issue=2979|pages=1–33|date=August 7, 1990|format=PDF] However, in a 2004 analysis, it was found that "Rheocles" was paraphyletic, forming two distinct clades. "R. alaotrensis", "R. lateralis", and "R. wrightae" (all species that are not discernibly sexually dimorphic was recovered as the sister taxon of the rest of the bedotiids, including "Bedotia" sister to "R. vatosa" + "R. derhami". "R. pellegrini" and "R. sikorae" were excluded from this study due to lack of available material, however, "R. sikorae" is considered to be the sister taxon to "R. wrightae".cite journal|url=http://research.amnh.org/scicomp/pdfs/Sparks_Smith2004b.pdf|title=Phylogeny and biogeography of the Malagasy and Australasian rainbowfishes (Teleostei: Melanotaenioidei): Gondwanan vicariance and evolution in freshwater|first=John S.|last=Sparks|coauthors=Smith, W. Leo|journal=Molecular Phylogenetics and Evolution|volume=33|year=2004|pages=719–734|format=PDF|doi=10.1016/j.ympev.2004.07.002]

Description

"Rheocles" species are robust bedotiids with little lateral body compression. "R. vatosa" and "R. derhami" are sexually dimorphic, with males exhibiting larger adult size, enhanced coloration and pigmentation, as well as pronounced development of the unpaired fins.

Conservation

Its close association with forested biotopes suggests that, like so many other rainforest-adapted series, "Rheocles" is extremely vulnerable to deforestation pressure. It has been suggested that "R. sikorae" and "R. wrightae" are already extinct.

References