Diagnosis_Genus: Bagre Cloquet. The following exclusive and shared characters distinguishes Bagre from the remaining ariid genera: about half of anterior cranial fontanel limited by posterior branches of mesethmoid; anterior infraorbital shaped like number seven; posterior infraorbital conspicuously curved medially;  lower end of subvertebral process rounded; maxillary long and thin; maxillary condyles well developed; palatine claviform, anteriorly very broad; lower part of palatine with a bony crest; anterior process of metapterygoid very large; third basibranchial hourglass shaped its posterior portion shorter and wider than anterior; second dorsal process of cleithrum on inferior part of lateral face of this bone; maxillary barbel compressed, tape-like; one pair of mental barbells; lachrymal with two anterior and one mesial branches (shared with Batrachocephalus); occipital process ventral crest developed through the entire length of the process (shared with Amphiarius, Aspistor, Cathorops, Cephalocassis, Cinetodus, Hemiarius, Nedystoma, Nemapteryx, Pachyula and Sciades platypogon); contact face between transcapular process and basioccipital wide and depressed (shared with Amphiarius, Arius gagora, A. maculatus, A. manillensis, Aspistor, Cathorops, Cryptarius, Doiichthys, Nedystoma, Nemapteryx, Notarius, Plicofollis platystomus and Potamosilurus latirostris); parasphenoid wing process very long and thin [shared with Amphiarius, Aspistor, Cathorops (with exception of C. dasycephalus), Cochlefelis, Hemiarius, Notarius (with exception of N. planiceps), Pachyula, Plicofollis platystomus, Potamarius, Potamosilurus (with exception of P. velutinus), Sciades emphysetus, S. passany and S. proops; face for articulation between palatine and lateral ethmoid slightly displaced to the anterior portion of former bone (shared with Doiichthys); tip of urohyal medial process bifid (shared with Doiichthys); urohyal lateral processes as long as or longer than medial process (shared with Potamarius); transversal crest associated with neural spine of fourth vertebra very high (shared with Amphiarius, Batrachocephalus, Cathorops, Cinetodus, Cryptarius, Ketengus, Hemiarius, Nemapteryx, Nedystoma, Notarius planiceps, Osteogeneiosus, Pachyula and Sciades platypogon); median crest associated with neural spine of third vertebra very high (shared with Amphiarius, Aspistor, Cathorops, Cephalocassis, Cinetodus, Hemiarius,Nedystoma, Nemapteryx, Pachyula and Sciades platypogon); more than 39 caudal vertebrae (shared with Cochlefelis); base of adipose fin very short, less than one-half as long as  anal-fin base (shared with Brustiarius, Cathorops, Cryptarius, Netuma and Plicofollis (with exception of P. platystomus); pectoral-fin spine prolonged as a tape-like filament (shared with Arius madagascariensis); lateral line bifurcated at caudal region (shared with Arius, Batrachocephalus, Ketengus, Netuma, Osteogeneiosus, Plicofollis and Sciades couma), (Marceniuz & Menezes 2007).

Diagnosis_species:  Silurus marinus Mitchill. Head large, depressed. Mouth wide, bearded by long tentacula. Body lengthened, naked. First of the pectoral fins, or of the first dorsal fin, toothed backward. A splendid fish, twenty inches long; four inches deep; and three and a half wide. Taken June 30th, 1814. Two whiskers, between five and six inches long, projecting from the upper lip, near the corners of the mouth. Two cirrbi, near one inch and a half long, depending from the chin. A bony ray in front of the first dorsal fin two inches and a half long; a cartilage spliced to it, as it were, and continued two and a half inches longer, making together a dorsal projection five inches long. First rays of each pectoral fin bony, with reversed spines behind, and about three inches long; from which a cartilage is continued about three inches; making together six inches.Both the dorsal and pectoral bony rays are notched in front, but not serrated enough to hold fast or a scratch. the several cartilaginous continuations are smooth on the anterior part; but have the apparance of serae on the posterior edge. Yet these serrae are invested in a membranewhich shelters them from the touch. two dorsal fins, the foremost of which is pretty far forward, and consists of eight rays. The bindmost pretty far back, and adipose without rays. the distance between them six inches. Tail deeply forked; the extreme rays somewhat converging; but nevertheless the distance between them exceeds four inches. Skin has a silly softness. Back glossy blue, with clouds and shades of green. Lateral line almost straight. Below that the colour a silky white, down to the belly, which is a milk white. Is an exquisite fish for eating. Ventral fins far back. they are inclined somewhat to red. Dorsal and pectoral fins have more of the ruddy; and the anal and caudal most of all. Rays Br. 4. P. 13. D. 8.-2d fleshy. V. 6. A. 22. C. 19.
 
Body_adults_length: 50 cm
Body_max_length: 69 cm
Body_juveniles_length: 80-100 mm
Body_length_male_sexual_maturity: 54.9 cm
Body_length_female_sexual_maturity: 50.5 cm
Body_max_weight: 4.4 kg
Boday_eggs_length: 15-26 mm (at fertilization)
Sequence_5'rag1: DQ492553 (Sullivan et al. 2006)
Sequence_3'rag1: DQ492524 (Sullivan et al. 2006)
Sequence_rag2: DQ492411 (Sullivan et al. 2006)
Toxicity: Yes (Vibrio parahaemolyticus and Vibrio vulnificus bacteria) (The dorsal and pectoral fins are equipped with a serrated erectile spine, both of which are venomous)