Xiphostoma lateristriga Boulenger, 1895
Boulengerella is named after the Belgian-British zoologist George Albert Boulenger (1858-1937).
Lateristriga derives its name from the Latin words “latus”, meaning ‘flank’, and “striga”, meaning ‘row, strip’, referring to the lateral body stripe.
- Order: Characiformes
- Family: Ctenoluciidae
The type locality of this species is ‘Manaus, Brazil’, and recent records indicate that it is limited to the Rio Negro basin in Brazil and Colombia, as well as certain areas of the upper Orinoco River in Venezuela.
This species seems to be restricted to blackwater rivers and their tributaries, where the water is usually darkly stained with humic acids and other compounds released by decomposing organic matter. The dissolved mineral content is generally insignificant, and the pH levels can be as low as 3.0 or 4.0.
Maximum Standard Length
The largest specimen on record measured 258 mm in length.
It is recommended to have an aquarium with base dimensions of 240 x 90 cm or larger.
Although not particularly demanding, this fish appreciates some surface cover in the form of floating or overhanging vegetation. To ensure optimal conditions, it is recommended to maintain a high level of dissolved oxygen and moderate water movement in the aquarium by using external filters, powerheads, airstones, etc., as necessary.
As this species requires stable water conditions, it should never be introduced to newly established aquariums. Weekly water changes of 30-50% aquarium volume are mandatory for its well-being.
Given its tendency to jump, a tightly-fitting cover is essential, and it may be beneficial to cover the back and sides of the aquarium to prevent the fish from swimming into the glass, particularly in small or cramped spaces where it can become skittish.
- Temperature: 22 – 28 °C
- pH: 4.0 – 7.0
- Hardness: 18 – 179 ppm
This species is an obligate predator that feeds mainly on smaller fishes and insects in the wild but can adapt well to dead alternatives in captivity.
For smaller specimens, suitable food options include bloodworm, small earthworms, and chopped prawn. Adult specimens can be fed strips of fish flesh, whole prawns or shrimp, mussels, live river shrimp, and larger earthworms.
Insects such as crickets are also appropriate to use as food, but it is best to feed them fish flakes or some form of vegetable matter beforehand to fill their stomachs before offering them to the fish.
Like most predatory fishes, this species should not be fed mammalian or avian meat, such as beef heart or chicken. Some of the lipids contained in these cannot be properly metabolized by the fish and can cause excess fat deposits and organ degeneration.
Similarly, there is no benefit to using ‘feeder’ fish such as livebearers or small goldfish, as they carry the risk of introducing parasites or disease, and typically do not have a high nutritional value unless properly conditioned beforehand.
Behaviour and Compatibility
This species is peaceful with anything too large to swallow and can be kept in a community aquarium, provided that tankmates are chosen with care.
It is best to avoid aggressively territorial or very competitive species and instead choose similarly-sized, placid fishes such as Geophagus or Acestrorhynchus spp., as well as many doradid or loricariid catfishes.
This species is not aggressive towards conspecifics, with juveniles in particular exhibiting a marked schooling instinct. While older individuals tend to be more solitary, they still group together from time to time, and it is best to maintain them in numbers of four or more.
This species has several vernacular names, including ‘Pirá-pacu’, ‘Pira-pucu’ or ‘Diente de cao’ (central Amazon), ‘Bicuda’ or ‘Uena’ (rio Tocantins), ‘Bicuda’ (rio Tapajós), ‘Aguejeta’ or ‘Picua’ (Venezuela), and ‘Moruwi’ or ‘Pirapoko’ (Guyana).
One of the distinguishing characteristics of this species is that the dorsal-fin base is mostly located posterior to a vertical line through the anal-fin origin, which sets it apart from all other congeners except B. maculata. B. lateristriga can be distinguished from B. maculata by the presence of a thin, dark stripe extending from the rear of the orbit to the caudal peduncle (vs. a stripe limited to the postorbital surface of the head when present), the presence (vs. absence) of distinct, dark crossbars on the lobes of the caudal-fin, the absence (vs. presence) of randomly-distributed dark spots on the upper body, 55-65 (vs. 73-84) predorsal scales, 14-17 (vs. 17-23) scale rows between the dorsal-fin origin and ventral midline, and a relatively short (vs. relatively long) dorsal-fin. Both species also have a broader dark midlateral stripe on the body, which tends to be more well-defined in B. lateristriga than in B. maculata.
Boulengerella can be distinguished from Ctenolucia, the only other genus currently contained in the family Ctenolucidae, by several derived features, including possession of 87-124 (vs. 45-50) lateral line scales, the presence of a strongly (vs. weakly) developed fleshy appendage at the tip of the snout, and the absence (vs. presence) of fleshy flaps on the lower jaw.
Within the order Characiformes, the family Ctenoluciidae is distinguished by a set of synapomorphic characters, including a tapering body shape, elongate jaw shape, and possession of many small teeth with curved tips arranged in a single series within each jaw.
Characiformes is one of the most diverse orders of freshwater fishes, currently including close to 2000 valid species distributed among 19 families.
The vast taxonomical and morphological diversity of Characiformes has historically made it difficult for researchers to resolve genetic relationships, with many genera remaining incertae sedis.
In many cases, exhaustive individual study has been the only way to resolve these issues. However, modern molecular phylogenetic techniques have allowed some progress. A study by Calcagnotto et al. (2005) revealed some interesting hypotheses, suggesting that Ctenoluciidae belongs to a trans-Atlantic, monophyletic clade alongside the families Lebiasinidae and Hepsetidae. This assemblage further forms a sister group to Alestidae.
Other studies, such as Oliveira et al. (2011), have concluded that the family Erythrinidae is also closely related to this grouping, with Hepsetidae and Alestidae being more distant.
- Calcagnotto, D., S. A. Schaefer and R. De Salle, 2005 – Molecular Phylogenetics and Evolution 36(1): 135-153
Relationships among characiform fishes inferred from analysis of nuclear and mitochondrial gene sequences.
- Oliveira, C. A., G. S. Avellino, K. T. Abe, T. C. Mariguela, R. C. Benine, G. Orti, R. P. Vari, and R. M. Corrêa e Castro, 2011 – BMC Evolutionary Biology 11(1): 275-300
Phylogenetic relationships within the speciose family Characidae (Teleostei: Ostariophysi: Characiformes) based on multilocus analysis and extensive ingroup sampling.
- Reis, R. E., S. O. Kullander and C. J. Ferraris, Jr. (eds.), 2003 – EDIPUCRS, Porto Alegre: i-xi + 1-729
Check list of the freshwater fishes of South and Central America. CLOFFSCA.
- Vari, R. P., 1995 – Smithsonian Contributions to Zoology 564: 1-97
The Neotropical fish family Ctenoluciidae (Teleostei: Ostariophysi: Characiformes): supra and intrafamilial phylogenetic relationships, with a revisionary study.