''Chalceus guaporensis'' is a species of freshwater fish in the family
Chalceidae that inhabits northern
South America
South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...
. Alongside ''
C. epakros'' and ''
C. spilogyros'', it was added to the genus ''
Chalceus
''Chalceus'' is a genus of fish that inhabits freshwater habitats in South America. Members can be found in the Amazon River, Amazon and Orinoco basins, as well as in the The Guianas, Guianas and various tributaries of the former. It is the sole ...
'' in the year 2004.
Description
Visually, ''C. guaporensis'' is similar to other ''Chalceus'' species, with metallic scales and a vivid caudal fin (often reddish or pinkish). It is also within the average size range of the genus, reaching 17.4 cm
SL.
It has a darker stripe down each side that reaches the caudal peduncle;
''C. guaporensis'' and ''C. epakros'' are the only two members of the genus ''Chalceus'' to sport this lateral stripe, differentiating them from the other three.
''C. guaporensis'' also usually has humeral spots (a dark spot above each pectoral fin), but they are not as well-defined as those in ''C. spilogyros'' or ''C. epakros.''
''C. guaporensis'' and ''C. epakros'' share a more elongated and pointed snout than other ''Chalceus'' species, but it is more pronounced in ''C. epakros''.
[Zanata, Angela M. and Vari, Richard P]
The family Alestidae (Ostariophysi, Characiformes): a phylogenetic analysis of a trans-Atlantic clade
Zoological Journal of the Linnean Society (2005).
''Chalceus guaporensis'' and ''C. epakros'' also both lack a
fontanel
A fontanelle (or fontanel) (colloquially, soft spot) is an human body, anatomical feature of the infant human skull comprising soft Membrane, membranous gaps (suture (joint), sutures) between the cranial bones that make up the calvaria (skull), ...
(soft, membranous spot) between the parietal and frontal bones of the head.
However, ''C. guaporensis'' has seven
pelvic fin
Pelvic fins or ventral fins are paired fins located on the ventral (belly) surface of fish, and are the lower of the only two sets of paired fins (the other being the laterally positioned pectoral fins). The pelvic fins are homologous to the hi ...
rays, as opposed to eight in other ''Chalceus'' species, which is the most certain method of visual identification.
Etymology
The specific name ''guaporensis'' is from the
Guaporé River
Guaporé River (, ) is a river in western Brazil and northeastern Bolivia. It is long; of the river forms the border between Brazil and Bolivia.
The Guaporé is part of the Madeira River basin, which eventually empties into the Amazon River. T ...
in
Bolivia
Bolivia, officially the Plurinational State of Bolivia, is a landlocked country located in central South America. The country features diverse geography, including vast Amazonian plains, tropical lowlands, mountains, the Gran Chaco Province, w ...
, one of ''C. guaporensis's'' habitats, with the Latin suffix "-ensis" denoting a place of origin;
compare ''Lynx canadensis'', the
Canada lynx
The Canada lynx (''Lynx canadensis'') or Canadian lynx is one of the four living species in the genus ''Lynx''. It is a medium-sized wild cat characterized by long, dense fur, triangular ears with black tufts at the tips, and broad, snowshoe- ...
, or ''Sotalia guianensis'', the
Guiana dolphin
The Guiana dolphin (''Sotalia guianensis''), also known as the estuarine dolphin or costero, is a dolphin found in the coastal and estuary waters to the north and east of South America, and east of Central America. It is a member of the oceanic ...
. It is the only member of the genus ''Chalceus'' to be named after a location.
The genus name ''Chalceus'' comes from the Greek word "chalkos", which means "copper".
This in turn is from the original description of the first ''Chalceus'' species, the
pinktail chalceus (''C. macrolepidotus''), wherein
Georges Cuvier
Jean Léopold Nicolas Frédéric, baron Cuvier (23 August 1769 – 13 May 1832), known as Georges Cuvier (; ), was a French natural history, naturalist and zoology, zoologist, sometimes referred to as the "founding father of paleontology". Cuv ...
noted that its scales were coppery ("sometimes golden") when preserved in alcohol.
Taxonomy
''Chalceus guaporensis'' was named in the year 2004 by Brazilian biologists