Entomocorus
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| Entomocorus | ||||||||||||||||
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 Transformed male Entomocorus radiosus
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| Entomocorus benjamini Eigenmann, 1917 |
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Entomocorus is a genus of catfishes (order Siluriformes) of the family Auchenipteridae.
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[edit] Taxonomy and phylogeny
Entomocorus was first described by Carl H. Eigenmann in 1917 with E. benjamini as type species by monotypy. Only a few phylogenetic diagnoses have been presented since.[1]
Entomocorus is included as the basal member in the Auchenipterus-Group by Carl H. Ferraris; this group also includes Auchenipterus and the sister groups Epapterus and Pseudepapterus. This group is sister to the Ageneiosus-Group, which includes the genera Ageneiosus and Tetranematichthys. These groups, along with the genus Trachelyopterus, form the tribe Auchenipterini. However, the placement of Entomocorus is problematic due to the loss of some characteristics of that diagnose Auchenipteridae and Auchenipterini.[1] Relationships between species of Entomocorus are unknown.[1]
[edit] Distribution
Entomocorus species are all found in lowland cis-Andean South America.[1] E. benjamini is endemic to the upper and middle Madeira River in Brazil and Bolivia. E. gameroi occurs in the llanos of the Orinoco River in Venezuela.[1] E. melaphareus has been found in the middle and lower Amazon.[2] E. radiosus is endemic to the Mato Grosso Pantanal area in the upper Paraguay River.[1]
[edit] Description
Entomocorus species are small fish, growing to 5.9–7.0 centimetres SL.[3][4][5][6] Sexual dimorphism is evident in all species except for E. benjamini; in this species, transformed males have yet to be found. In the other species, transformed males have stiff, ossified maxillary barbels, an elongated dorsal-fin spine, ventrally-directed pectoral-fin spine hooks, very elongated pelvic-fin unbranched rays, and a rotated anal-fin base.[1]
The four different Entomocorus species are not easily distinguished by differences in meristics or morphometrics; however, they are easily be distinguished by pigmentation, especially in caudal fin markings. In E. benjamini, the distal half of dorsal caudal fin lobe and the edge of the ventral lobe is pigmented. In E. gameroi, an oblique band crossing from the dorsal profile of the caudal peduncle to the middle-upper rays of the caudal fin. In E. melaphareus, an inconspicuous patch exists on the dorsal lobe of the caudal fin. In E. radiosus, the distal half of both the dorsal and ventral caudal fin lobes is pigmented.[1] E. melaphareus also has pigmented pectoral and pelvic fins, while these fins in the other three species are unpigmented. E. radiosus is the only species that can be diagnosed by meristics; its anal-fin base is longer and has more branched anal-fin rays.[1]
[edit] Ecology
Entomocorus are nocturnal, pelagic catfish that feed near the surface on invertebrates (primarily insects) and on zooplankton (mainly microcrustaceans).[1] E. benjamini has been classified as an invertivore that feeds on aquatic and terrestrial invertebrates (primarily insects), zooplankton (including cladocerans, copepods, and rotiferans), and both aquatic and terrestrial vegetation.[1] E. gameroi is classified as an omnivore with a tendency towards insectivory; it has been found to eat cladocerans, copepods, and water mites, as well as ostracods, insects including coleopterans, dipterans, ephemeropterans, hemipterans, and seeds and other vegetal matter.[1][7] It has been noted that a single fish could ingest as many as 1700 planktonic crustaceans in a single night, when this species feeds near the water surface.[7] E. radiosus is a zooplanktivore which also eats insects; this species predominantly consumes microcrustaceans (cladocerans, copepods, and ostracods), but also fed on insects (ephemeropterans, coleopterans, and hemipterans).[1]
During the day, E. gameroi rests motionlessly. This species has been found to hide among the submerged roots of water hyacinth during the day, but may also use alternative sources of shelter such as wood, rocks, and other benthic substrata in hyacinth-free locations.[7]
The reproductive cycle of E. gameroi has been studied, and it is believed that this species is short-lived. Fish of this species reach sexual maturity within a year and perish soon after. Members of a given cohort are never found in the studied lake the next year.[7]
[edit] References
- ^ a b c d e f g h i j k l m Reis, Roberto E.; Borges, Thiago A. K. (2006). "The South American Catfish Genus Entomocorus (Ostariophysi: Siluriformes: Auchenipteridae), with the Description of a New Species from the Paraguay River Basin". Copeia (3): 412-422.
- ^ Akama, Alberto; Ferraris, Carl H., Jr. (2003). "Entomocorus melaphareus, a new species of auchenipterid catfish (Osteichthyes: Siluriformes) from the lower and middle reaches of the rio Amazonas" (PDF). Neotropical Ichthyology 1 (2): 77-82.
- ^ "Entomocorus benjamini". FishBase. Ed. Ranier Froese and Daniel Pauly. January 2008 version. N.p.: FishBase, 2008.
- ^ "Entomocorus gameroi". FishBase. Ed. Ranier Froese and Daniel Pauly. January 2008 version. N.p.: FishBase, 2008.
- ^ "Entomocorus melaphareus". FishBase. Ed. Ranier Froese and Daniel Pauly. January 2008 version. N.p.: FishBase, 2008.
- ^ "Entomocorus radiosus". FishBase. Ed. Ranier Froese and Daniel Pauly. January 2008 version. N.p.: FishBase, 2008.
- ^ a b c d Rodriguez, Marco A.; Richardson, Susan E.; Lewis, William M. Jr. (1990). "Nocturnal Behavior and Aspects of the Ecology of a Driftwood Catfish, Entomocorus gameroi (Auchenipteridae)". Biotropica 22 (4): 435-438.
