Potamarius

Alexandre P. Marceniuk & Naércio A. Menezes, 2007, Systematics of the family Ariidae (Ostariophysi, Siluriformes), with a redefinition of the genera., Zootaxa 1416, pp. 1-126 : 96-98

publication ID

z01416p001

publication LSID

lsid:zoobank.org:pub:FFC65592-D8DB-41BE-AEAC-A41EAB6C6185

DOI

https://doi.org/10.5281/zenodo.6237064

persistent identifier

https://treatment.plazi.org/id/3A1CA07A-1945-B868-42C1-D59184489B32

treatment provided by

Thomas

scientific name

Potamarius
status

 

Potamarius View in CoL View at ENA   ZBK Hubbs & Miller, 1960

(Fig. 84)

Potamarius   ZBK Hubbs & Miller, 1960: 101. Type species: Conorhynchos nelsoni   ZBK Evermann & Goldsborough, 1902. Type by original designation. Gender: masculine.

Diagnosis. The following combination of exclusive (1 to 3) and shared (4 to 14) characters distinguishes Potamarius   ZBK from the remaining ariid genera: (1) optic foramen very large; (2) interopercle subrectangular (fig. 85); (3) lateral processes of urohyal completely free from bony blade contacting medial process of the bone (fig. 86); (4) mesethmoid median portion thin (fig. 87) [shared with Arius   ZBK (with exception of A. caelatus   ZBK and A. madagascariensis   ZBK ), Cathorops , Cephalocassis   ZBK , Cinetodus   ZBK , Ketengus   ZBK , Osteogeneiosus   ZBK and Pachyula   ZBK ]; (5) lateral horn of lateral ethmoid very long and pointing backward (fig. 87) [shared with Arius   ZBK (with exception of Arius caelatus   ZBK ), Doiichthys   ZBK and Plicofollis   ZBK (with exception of P. platystomus and Plicofollis tenuispinis )]; (6) anterior portion of vomer acute and conspicuous [shared with Amphiarius , Arius   ZBK , Aspistor   ZBK , Cephalocassis   ZBK , Cinetodus   ZBK , Osteogeneiosus   ZBK , Plicofollis   ZBK , Notarius   ZBK (with exception of N. planiceps ), Pachyula   ZBK and Potamosilurus macrorhynchus ]; (7) vomerine tooth plate absent [shared with Amphiarius , Arius   ZBK , Batrachocephalus   ZBK , Carlarius , Cathorops (with exception of C. dasycephalus ), Cephalocassis   ZBK , Cinetodus   ZBK , Cryptarius   ZBK , Doiichthys   ZBK , Genidens genidens , Ketengus   ZBK , Nedystoma   ZBK , Osteogeneiosus   ZBK , Pachyula   ZBK , Plicofollis platystomus and Potamosilurus velutinus ]; (8) frontal bones without mesial laminar projection (fig. 87) (shared with Amphiarius , Arius   ZBK , Aspistor   ZBK , Cathorops , Cephalocassis   ZBK , Cryptarius   ZBK , Doiichthys   ZBK , Galeichthys   ZBK , Hemiarius   ZBK , Nedystoma   ZBK , Nemapteryx   ZBK , Osteogeneiosus   ZBK and Potamosilurus latirostris ); (9) orbitosphenoid without lateral expansion [shared with Amphiarius , Aspistor   ZBK , Bagre , Batrachocephalus   ZBK , Cathorops , Cephalocassis   ZBK , Cochlefelis   ZBK , Cryptarius   ZBK , Doiichthys   ZBK , Galeichthys   ZBK , Hemiarius   ZBK , Ketengus   ZBK , Nedystoma   ZBK , Nemapteryx   ZBK , Neoarius   ZBK , Osteogeneiosus   ZBK , Notarius   ZBK (with exception of N. planiceps ), Pachyula   ZBK , Plicofollis platystomus , Potamosilurus latirostris , Sciades couma , S. emphysetus   ZBK , S. passany , S. proops , S. seemanni and S. sagor ]; (10) parasphenoid wing-like process absent (shared with Batrachocephalus   ZBK , Cephalocassis   ZBK , Cryptarius   ZBK , Doiichthys   ZBK , Ketengus   ZBK , Nedystoma   ZBK , Nemapteryx   ZBK and Osteogeneiosus   ZBK ); (11) premaxillary almost as long as wide (shared with Cathorops , Cephalocassis   ZBK and Cinetodus   ZBK ); (12) metapterygoid 1.5 times as long as high [shared with Cathorops (with exception of Cathorops dasycephalus ), Cephalocassis   ZBK , Cinetodus   ZBK , Cryptarius   ZBK , Pachyula   ZBK and Plicofollis   ZBK ]; (13) metapterygoid anterior process truncate [shared with Cinetodus   ZBK , Cochlefelis   ZBK , Pachyula   ZBK , Plicofollis   ZBK and Potamosilurus (with exception of P. velutinus )]; (14) distance from optic foramen and trigeminofacial complex equal to width of complex (shared with Bagre and Galeichthys   ZBK ); (15) third basibranchial in form of a long and thin hourglass (shared with Cochlefelis   ZBK and Galeichthys   ZBK ); (16) number of ribs equal to or less than 14 (shared with Amphiarius , Arius   ZBK , Aspistor   ZBK , Batrachocephalus   ZBK , Brustiarius   ZBK , Cathorops , Cephalocassis   ZBK , Cinetodus   ZBK , Cryptarius   ZBK , Doiichthys   ZBK , Galeichthys   ZBK , Hemiarius   ZBK , Ketengus   ZBK , Nedystoma   ZBK , Nemapteryx   ZBK , Osteogeneiosus   ZBK , Pachyula   ZBK , Plicofollis platystomus and Potamosilurus ).

Supplementary morphological characters. Cephalic shield granulated visible under the skin; a moderately developed fenestra limited by lateral ethmoid and frontal visible under the skin; medial groove of neurocranium very distinct, limited by frontal bones and/or on supraoccipital; posterior cranial fontanel moderately developed, long and narrow; fenestra limited by supraoccipital, pterotic and sphenotic absent; fossa limited by pterotic, supracleithrum and extrascapular relatively large; epioccipital not invading dorsal portion of cephalic shield; occipital process triangular, moderately long and wide, progressively narrower toward its posterior part; anterior and median nuchal plates fused and indistinct, forming a structure of semi-lunar aspect; tooth plates associated with vomer absent; accessory tooth plates absent or rudimentary; maxillary barbel fleshy and cylindrical; base of adipose fin moderately long, about half as long as anal-fin base; lateral line not bifurcated at caudal region, reaching base of caudal-fin upper lobe; cleithrum wide, with second dorsal process on its upper portion; posterior cleithral process of moderate length, distinct from second dorsal process of cleithrum.

Remarks. The type-species of the genus, Conorhynchos nelsoni   ZBK Evermann & Goldsborough, 1902 was characterized on the basis of characters observed in preserved specimens and data from the literature.

Distribution and habitat. Central and South America, freshwater.

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