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Auchenipterus nigripinnis (Boulenger, 1895)



his months factsheet (Sept. 2014) brings us to the South American family Auchenipteridae and a little known member from the Auchenipterus genera, the Paraguay Shark-cat, Auchenipterus nigripinnis.

Your first thoughts when you see this species is the resemblance to the shark cats of the Pangasidae catfish family of Asia, hence its common name. But the likeness to this family stops there as the Auchenipterus do not grow to the huge sizes of the Pangaidae shark cats and A. nigripinnis will reach a manageable size of 8ins ( 20.5cm.)


Auchenipterus nigripinnis

The genus Auchenipterus is closely related to and is similar to, Epapterus and Pseudepapterus. Distinguished from all species except A. brachyurus by the following combination of characters: anal fin origin posterior to the middle of the body; and caudal fin without terminal band, but with a chevron-shaped dark mask near base of each lobe. The caudal markings are the very best way to identify this species and from the aforementioned A. brachyurus which has two horizontal bands running through the caudal fin lobes.

 

 

Auchenipterus nigripinnis

 

As mentioned earlier this species is not seen very often in the hobby and only arrived via Aquarium Glaser in Germany in 2009, but a group of them in a large tank will very often be seen during the day especially at feeding time. They do not eat plants so a planted setup with added floating plants would be advantages to this species. In its natural habitat, it lives in the LaPlata basin of Argentina, Brazil, Paraguay, and Uruguay so lower temperatures are the norm for this species.

 



Characteristics
Body comparatively deep, elongate; body depth an anal fin origin 20-25% SL; body compressed, width at anal fin origin approximately 42% (38-45%) of body depth at that point. Barbels slender, maxillary pair extending at least to tip of adpressed pectoral fin spine. Mandibular barbels originate in transverse row at margin of lower jaw, just lateral to jaw symphysis; barbels extend posteriorly at least to pectoral fin base, basal portion of each barbel rests in shallow groove that extends posteriorly approximately to vertical through posterior margin of orbit. Nasal barbels absent. Caudal fin forked, lobes pointed. Lobes somewhat asymmetrical, longest branched ray of upper lobe longer than than that of lower lobe.

Colour
Body silvery white, grey dorsally. Abdomen and underside of head white. Complete midlateral, posteriorly tapering, dark stripe present in some specimens, but often stripe extends from humeral region posteriorly only to region above pelvic fin base. Dorsal fin with scattered dark pigmentation basally, especially anteriorly, but pigmentation does not extend far into fin membranes. Dorsal fin with thin dark margin in some specimens, width of marginal pigmentation varies, but always decreases posteriorly. Caudal fin with lightly scattered pigmentation along margin not usually forming dark marginal bar. Middle of upper caudal fin lobe with broad oblique, and somewhat curved dark bar. Lower caudal fin lobe with thin dark bar, more basally situated.

Aquarium Care
Good community catfish with normal sized patrons.

 

Compatibility
Not to be trusted with small Tetras for instance, which will be picked of at night on its twilight patrols.

Sexing
Females grow larger than the males. The males have an extended dorsal fin. Females have a slimmer snout than the males which is broader. As per with this family the anal fin is modified in males with the last unbranched and the first branched anal-fin rays elongate, enlarged, and joined together to form the structural support of an intromitten organ. In mature females, the last unbranched, and 5 or 6 anterior branched, anal-fin rays are very slightly longer than the subsequent rays.
 

Breeding

Not reported but would be along the lines of other members of this family. Internal fertilisation with the eggs deposited 24-48 hours later. The eggs being encased in a gelatine mass and placing their adhesive eggs on the underside of wood with no broodcare after the event.

Feeding
Can be fed most aquarium fare such as good quality flake, white worm, tablet and pellet foods and frozen foods such as bloodworm. Better to feed at lights out until they get accustomed to the daytime feeding regime when they may very well join in.

Etymology
Auchenipterus: Auchen; auchenos = neck; pteron = wing, fin.
nigripinnis:
Black fin.

Glossary of Terms:

Anal fin: The median, unpaired, ventrally located fin that lies behind the anus, usually on the posterior half of the fish.

Maxillary barbels: Pertaining to the upper jaw. (maxillary barbels)

Mandibular barbels: Pertaining to the lower jaw. (mandibular barbels).
Caudal:
The tail.
Pectoral fins:
The paired fins just behind the head.
Pelvic fins:
The paired fins, between the pectorals and the anal fins. (also referred to as ventrals)
S.L.
: Standard length as measured from the snout to the caudal peduncle.
Dorsal fin:
The primary rayed fin(s) on top of the body

Reference
Ferraris, C.J. Jr., 2007. Checklist of catfishes, recent and fossil (Osteichthyes: Siluriformes), and catalogue of siluriform primary types. Zootaxa 1418:1-628.
Ferraris, C.J. Jr., 1999. The South American catfish genus Auchenipterus Valenciennes, 1840 (Ostariophysi: Siluriformes: Auchenipteridae) : monopoly and relationships, with a revisionary study. Zoological Journal. Vol. 126, Part 4, 1999.

Aquarium Glaser http://www.aquarium-glaser.com/en/auchenipterus-nigripinnis_en_1070.html

Photo Credits

 ©  Johnny Jensen's Photographic Library

Factsheet 219

Synonyms:
Euanemus nigripinnis, Auchenipterus paysanduanus 
Common Name:
Paraguay Shark-cat
Family:
Auchenipteridae
Subfamily:
None
Distribution:
South America: La Plata River basin. Known only from the Rio de La Plata drainage. In the Rio Paraná, the species has been recorded above the junction of the Rio Paraguay. Type locality: Paraguay.
Size: 
20.5cm. (8ins)
Temp:
18-24°c (63-75°f.)
pH.:
6.5 - 7.2.
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                                                                                                                                  Factsheet 219 = updated September 7, 2016 , © ScotCat 1997-2016 Go to Top