Ariidae Bleeker

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: 111-121

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z01416p001

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scientific name

Ariidae Bleeker
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[[ Family Ariidae Bleeker  ]]

Identification key to genera

This key is based on the use of external morphological characters allowing for the identification of taxa without the need of osteological preparations. Being artificial, it has to be used from its beginning since generic identification can be reached through different entries.

1. Maxillary barbel present ............................................................................................................................ 2

- Maxillary barbel absent .................................................................................................. Batrachocephalus  ZBK 

2. Mental barbels present; maxillary barbel soft, fleshy along its entire length ............................................ 3

- Mental barbels absent; maxillary barbel hard, bony along its entire length ....................... Osteogeneiosus  ZBK 

3. Two pairs of mental barbels; maxillary barbel cylindrical ........................................................................ 4

- A single pair of mental barbels; maxillary barbel compressed, tape-like ........................................... Bagre 

4. Cephalic shield clearly exposed, ornamented with grooves, ridges and granules, covered by a very thin layer of skin; anterior and median nuchal plates indistinct; posterior cleithral process and second dorsal process of cleithrum distinct and pointed .................................................................................................. 5

- Cephalic shield only slightly exposed, covered by musculature and thick skin; anterior and median nuchal plates conspicuous; posterior cleithral process and second dorsal process of cleithrum connected by a bony blade ................................................................................................................................. Galeichthys  ZBK 

5. Premaxillary and dentary with several rows of conical, viliform or molar-like teeth ............................... 6

- Premaxillary and dentary teeth with a single row of incisiform teeth .......................................... Ketengus  ZBK 

6. Adipose fin long, its base as long as anal-fin base .................................................................................... 7

- Adipose fin moderately long or short, its base no longer than one-half the length of anal-fin base ................................. 13

7. Anterior and median nuchal plates very reduced, forming a structure of semi-lunar aspect; posterior margin of occipital process concave; occipital process triangular shaped, moderately long and wide; accessory tooth plates bearing small conical teeth..................................................................................................... 8

- Anterior and median nuchal plates very large, square to pentagonal shaped; posterior margin of occipital process convex; occipital process round, very short and wide at base; accessory tooth plates large, bearing molar-like teeth ............................................................................................................................... Aspistor  ZBK 

8. Tooth plates associated with vomer present .............................................................................................. 9

- Tooth plates associated with vomer absent.............................................................................................. 10

9. Posterior cleithral process very short; accessory tooth plates transversely elongated and narrow............... ..................................................................................................................................................... Hemiarius  ZBK 

- Posterior cleithral process moderately long; accessory tooth plates large, triangular, oval or round........... ........................................................................................................................................................ Notarius  ZBK 

10. Posterior cleithral process very long; posterior cranial fontanel long and narrow .................................. 11

- Posterior cleithral process short or moderately long; posterior cranial fontanel wide and oval.............. 12

11. Accessory tooth plates present..................................................................................................... Cinetodus  ZBK 

- Accessory tooth plates absent....................................................................................................... Pachyula  ZBK 

12. Fenestra limited by supraoccipital, pterotic and sphenotic present; posterior cranial fontanel very large; posterior cleithral process very short.................................................................................... Cephalocassis  ZBK 

- Fenestra limited by supraoccipital, pterotic and sphenotic absent; posterior cranial fontanel large; posterior cleithral process moderately long ....................................................................................... Amphiarius 

13. Accessory tooth plates bearing large molar-like teeth............................................................................. 14

- Teeth of the accessory tooth plates small or absent, when present conical or viliform ........................... 16

14. Adipose fin very short, its base less than one-half length of anal-fin base; medial groove of neurocranium limited by frontal bones and also on supraoccipital; posterior cranial fontanel very reduced or absent ..................................................................................... 15

- Adipose fin moderately long, its base about one-half as long as anal-fin base; medial groove of neurocranium mostly or exclusively on supraoccipital; posterior cranial fontanel conspicuous, long and narrow ... .............................................................................................................................................................. Arius  ZBK 

15. Lateral line bifurcated at caudal region; posterior cleithral process moderately long................. Plicofollis  ZBK 

- Lateral line not bifurcated at caudal region; posterior cleithral process very short..................... Cathorops 

16. Lateral line not bifurcated at caudal region ............................................................................................. 17

- Lateral line bifurcated at caudal region ................................................................................................... 28

17. Temporal fossa present; fontanel limited by lateral ethmoid and frontal well developed, moderate to large .................................................................................................................................................................. 18

- Temporal fossa absent; fontanel limited by lateral ethmoid and frontal very reduced or inconspicuous..... .......................................................................................................................................................... Sciades 

18. Medial groove of neurocranium limited by frontal and/or supraoccipital, rudimentary or absent............................................................................................. 19

- Medial groove of neurocranium limited by frontal and/or supraoccipital, very distinct...................................................... 22

19. Posterior cleithral process very short; posterior cranial fontanel very large ........................................... 20

- Posterior cleithral process moderately long; posterior cranial fontanel moderate to large ..................... 21

20. Accessory tooth plates absent..................................................................................................... Nedystoma  ZBK 

- Accessory tooth plates present.................................................................................................... Doiichthys  ZBK 

21. Posterior cranial fontanel oval and well developed; mesethmoid moderately wide at region of anterior nostrils................................................................................................................................... Potamosilurus 

- Posterior cranial fontanel relatively long and narrow; mesethmoid very wide at region of anterior nostrils .................................................................................................................................................... Cochlefelis  ZBK 

22. Epioccipital not invading dorsal portion of cephalic shield .................................................................... 23

- Epioccipital invading dorsal portion of cephalic shield ................................................................ Carlarius 

23. Adipose fin very short, its base less than one-half length of anal-fin base .............................................. 24

- Adipose fin moderately long, its length about half as long as anal-fin base ........................................... 25

24. Tooth plates associated with vomer present ............................................................................... Brustiarius  ZBK 

- Tooth plates associated with vomer absent ................................................................................. Cryptarius  ZBK 

25. Posterior cleithral process moderately long; medial groove of neurocranium limited by frontal bones, but also on supraoccipital; posterior cranial fontanel reduced or absent or long and narrow ................................................................................... 26

- Posterior cleithral process very short; medial groove of neurocranium limited mainly by supraoccipital; posterior cranial fontanel very large and oval .......................................................................... Nemapteryx  ZBK 

26. Posterior cranial fontanel well developed, long and narrow ................................................................... 27

- Posterior cranial fontanel very reduced or absent ......................................................................... Genidens  ZBK 

27. Tooth plates associated with vomer absent; accessory tooth plates very reduced or absent ..... Potamarius  ZBK 

- Tooth plates associated with vomer present; accessory tooth plates large .................................... Neoarius  ZBK 

28. Tooth plates associated with vomer absent; adipose fin moderately long, its length about half as long as anal-fin base ......................................................................................................................................... Arius  ZBK 

- Tooth plates associated with vomer present; adipose fin very short, its base less than one-half length of anal-fin base ..................................................................................................................................... Netuma 

New classification of the Ariidae 

Family Ariidae  Bleeker, 1862

Amissidens  ZBK  Kailola, 2004

Amissidens hainesi  (Kailola, 2000)

Amphiarius  new genus

Amphiarius phrygiatus  (Valenciennes, 1840)

Amphiarius rugispinis  (Valenciennes, 1840)

Arius  ZBK  Valenciennes, 1840

Arius acutirostris  ZBK  Day, 1877 - sedis mutabilis

Arius africanus  Günther, 1867 - sedis mutabilis

Arius arenarius  ZBK  ( Müller & Troschel, 1849) - sedis mutabilis

Arius arius  (Hamilton, 1822)

Arius brunellii  ZBK  Zollezi, 1939 - sedis mutabilis

Arius burmanicus  ZBK  Day, 1870 - sedis mutabilis

Arius caelatus  ZBK  Valenciennes, 1840

Arius dispar  ZBK  Herre, 1926

Arius festinus  ZBK  Ng & Sparks, 2003 - sedis mutabilis

Arius gagora  (Hamilton, 1822)

Arius jatius  (Hamilton, 1822) - sedis mutabilis

Arius jella  ZBK  Day, 1877 - sedis mutabilis

Arius leptonotacanthus  ZBK  Bleeker, 1849 - sedis mutabilis

Arius macronotacanthus  ZBK  Bleeker, 1846 - sedis mutabilis

Arius maculatus  ZBK  (Thunberg, 1792)

Arius madagascariensis  ZBK  Vaillant, 1894

Arius malabaricus  ZBK  Day, 1877 - sedis mutabilis

Arius manillensis  ZBK  Valenciennes, 1840

Arius microcephalus  ZBK  Bleeker, 1855 - sedis mutabilis

Arius nenga  (Hamilton, 1822) - sedis mutabilis

Arius oetik  ZBK  Bleeker, 1846 - sedis mutabilis

Arius subrostratus  ZBK  Valenciennes, 1840 - sedis mutabilis

Arius uncinatus  ZBK  Ng & Sparks, 2003 - sedis mutabilis

Arius venosus  ZBK  Valenciennes, 1840 - sedis mutabilis

Aspistor  ZBK  Jordan & Evermann, 1898

Aspistor luniscutis  (Valenciennes, 1840)

Aspistor parkeri  (Traill, 1832)

Bagre  Cloquet, 1816

Bagre bagre  (Linnaeus, 1766)

Bagre marinus  (Mitchill, 1815)

Bagre panamensis  (Gill, 1863)

Bagre pinnimaculatus  (Steindachner, 1876)

Batrachocephalus  ZBK  Bleeker, 1846

Batrachocephalus mino  (Hamilton, 1822)

Brustiarius  ZBK  Herre, 1935

Brustiarius nox  (Herre, 1935)

Brustiarius proximus  (Ogilby, 1898) - sedis mutabilis

Brustiarius solidus  (Herre, 1935)

Carlarius  new genus

Carlarius gigas  (Boulenger, 1911) - sedis mutabilis

Carlarius heudelotii  (Valenciennes, 1840)

Carlarius latiscutatus  ( Günther, 1864)

Carlarius parkii  ( Günther, 1864)

Cathorops  Jordan & Gilbert, 1822

Cathorops agassizi  (Eigenmann & Eigenmann, 1888)

Cathorops aguadulce  (Meek, 1904)

Cathorops arenatus  (Valenciennes, 1840)

Cathorops dasycephalus  ( Günther, 1864)

Cathorops fuerthii  (Steindachner, 1877)

Cathorops hypophthalmus  (Steindachner, 1877)

Cathorops mapale  ZBK  Betancur-R. & Acero, 2005

Cathorops melanopus  ( Günther, 1864)

Cathorops multiradiatus  ( Günther, 1864)

Cathorops spixii  (Agassiz, 1829)

Cathorops steindachneri  (Gilbert & Starks, 1904)

Cathorops tuyra  (Meek & Hildebrand, 1923)

Cephalocassis  ZBK  Bleeker, 1858

Cephalocassis bleekeri  (Popta, 1900) - sedis mutabilis

Cephalocassis borneensis  (Bleeker, 1851)

Cephalocassis manillensis  (Valenciennes, 1840) - sedis mutabilis

Cephalocassis melanochir  (Bleeker, 1852)

Cinetodus  ZBK  Ogilby, 1898

Cinetodus carinatus  (Weber, 1913) - sedis mutabilis

Cinetodus froggatti  (Ramsay & Ogilby, 1886)

Cochlefelis  ZBK  Whitley, 1941

Cochlefelis danielsi  (Regan, 1908)

Cochlefelis dioctes  (Kailola, 2000) - sedis mutabilis

Cochlefelis insidiator  (Kailola, 2000) - sedis mutabilis

Cochlefelis spatula  (Ramsay & Ogilby, 1886)

Cryptarius  ZBK  Kailola, 2004

Cryptarius daugueti  (Chevey, 1932) - sedis mutabilis

Cryptarius truncatus  (Valenciennes, 1840)

Doiichthys  ZBK  Weber, 1913

Doiichthys novaeguineae  ZBK  Weber, 1913

Galeichthys  ZBK  Valenciennes, 1840

Galeichthys ater  ZBK  Castelnau, 1861

Galeichthys feliceps  ZBK  Valenciennes, 1840

Galeichthys peruvianus  ZBK  Lütken, 1874 - sedis mutabilis

Genidens  ZBK  Castelnau, 1855

Genidens barbus  ( Lacépède, 1803)

Genidens genidens  (Cuvier, 1829)

Genidens machadoi  ZBK  (Miranda-Ribeiro, 1918)

Genidens planifrons  (Higuchi, Reis & Araújo, 1982)

Hemiarius  ZBK  Bleeker, 1847

Hemiarius hardenbergi  (Kailola, 2000) - sedis mutabilis

Hemiarius harmandi  ZBK  Sauvage, 1880 - sedis mutabilis

Hemiarius stormii  (Bleeker, 1858)

Hemiarius sumatranus  (Anonymous, 1830)

Hemiarius verrucosus  (Ng, 2003) - sedis mutabilis

Ketengus  ZBK  Bleeker, 1847

Ketengus typus  ZBK  Bleeker, 1847

Nedystoma  ZBK  Ogilby, 1898

Nedystoma dayi  (Ramsay & Ogilby, 1886)

Nemapteryx  ZBK  Ogilby, 1908

Nemapteryx armiger  (De Vis, 1884)

Neoarius  ZBK  Castelnau, 1878

Neoarius augustus  (Roberts, 1978) - sedis mutabilis

Neoarius berneyi  (Whitley, 1941) - sedis mutabilis

Neoarius graeffei  (Kner & Steindachner, 1867)

Neoarius midgleyi  (Kailola & Pierce, 1988)

Neoarius pectoralis  (Kailola, 2000) - sedis mutabilis

Netuma  Bleeker, 1858

Netuma bilineatus  (Valenciennes, 1840)

Netuma thalassinus  ( Rüppell, 1837)

Notarius  ZBK  Gill, 1863

Notarius armbrusteri  Betancur-R. & Acero, 2006 - sedis mutabilis

Notarius biffi  ZBK  Betancur-R. & Acero, 2004 - sedis mutabilis

Notarius cookei  (Acero & Betancur-R., 2002) - sedis mutabilis

Notarius grandicassis  (Valenciennes, 1840)

Notarius insculptus  (Jordan & Gilbert, 1883) - sedis mutabilis

Notarius kessleri  (Steindachner, 1877) - sedis mutabilis

Notarius lentiginosus  (Eigenmann & Eigenmann, 1888)

Notarius neogranatensis  (Acero & Betancur-R., 2002) - sedis mutabilis

Notarius osculus  (Jordan & Gilbert, 1883) - sedis mutabilis

Notarius planiceps  (Steindachner, 1877)

Notarius troschelii  (Gill, 1863)

Osteogeneiosus  ZBK  Bleeker, 1846

Osteogeneiosus militaris  (Linnaeus, 1758)

Pachyula  ZBK  Ogilby, 1898

Pachyula conorhynchus  (Weber, 1913) - sedis mutabilis

Pachyula crassilabris  (Ramsay & Ogilby, 1886)

Plicofollis  ZBK  Kailola, 2004

Plicofollis argyropleuron  (Kuhl & van Hasselt, 1840)

Plicofollis crossocheilos  (Bleeker, 1846) - sedis mutabilis

Plicofollis dussumieri  (Valenciennes, 1840)

Plicofollis magatensis  (Herre, 1926) - sedis mutabilis

Plicofollis nella  (Valenciennes, 1840)

Plicofollis platystomus  (Day, 1877) - sedis mutabilis

Plicofollis polystaphylodon  (Bleeker, 1846)

Plicofollis tenuispinis  (Day, 1877)

Potamarius  ZBK  Hubbs & Miller, 1960

Potamarius grandoculis  (Steindachner, 1877)

Potamarius izabalensis  ZBK  Hubbs & Miller, 1960

Potamarius nelsoni  (Evermann & Goldsborough, 1902)

Potamosilurus  new genus

Potamosilurus coatesi  (Kailola, 1990) - sedis mutabilis

Potamosilurus latirostris  (Macleay, 1883)

Potamosilurus macrorhynchus  (Weber, 1913)

Potamosilurus robertsi  (Kailola, 1990) - sedis mutabilis

Potamosilurus velutinus  (Weber, 1907) - sedis mutabilis

Sciades  Müller & Troschel, 1849

Sciades assimilis  ( Gùnther, 1864)

Sciades bonillai  (Miles, 1945)

Sciades couma  (Valenciennes, 1840)

Sciades dowii  (Gill, 1863) - sedis mutabilis

Sciades emphysetus  ZBK  Müller & Troschel, 1849

Sciades felis  (Linnaeus, 1766)

Sciades guatemalensis  ( Günther, 1864)

Sciades herzbergii  (Bloch, 1794)

Sciades leptaspis  (Bleeker, 1862)

Sciades mastersi  (Ogilby, 1898) - sedis mutabilis

Sciades passany  (Valenciennes, 1840)

Sciades paucus  (Kailola, 2000) - sedis mutabilis

Sciades platypogon  ( Günther, 1864)

Sciades proops  (Valenciennes, 1840)

Sciades sagor  (Hamilton, 1822)

Sciades seemanni  ( Günther, 1864)

Sciades sona  (Hamilton, 1822) - sedis mutabilis

Sciades utarus  (Kailola, 1990) - sedis mutabilis

Discussion and comparison with previous classifications

The results obtained in this study are of primary importance for the systematics and taxonomy of the Ariidae  for a long time a matter of controversy and misunderstanding among ichthyologists worldwide. The characterization of the genera, definition of their limits and species composition has been a great challenge within the systematics of the Siluriformes. Presently about 130 species are recognized as valid, but many need to be better characterized taxonomically. The difficulties in recognizing species identity and monophyletic taxa are mainly due to the wide geographic distribution of the group and the overall similarity in the external morphology of their representatives coupled with lack of adequate series of specimens in museum collections. Thus studies aimed at more comprehensive approaches on systematics and phylogeny of the Ariidae  have not been entirely successful because of the above mentioned constraints.

Recently Kailola (1990a, 2004), Betancur-R. & Mejía (2000), Betancur-R. (2003), Betancur-R. & Acero (2004) and Betancur-R. et al. (2004) based on the cladistic method, presented a preliminary analysis of the phylogenetic relationships of part of the genera and species of the Ariidae  . Kailola (1990a) in an unpublished doctoral thesis discussed the relationships and zoogeography of the marine catfishes from New Guinea and Australia and Betancur-R. & Mejia (2000) and Betancur-R. (2003) did a similar study as part of the requirements for completion of the undergraduate program and a master’s dissertation respectively (not published) in Colombia and adjacent tropical waters. In both cases the authors examined only a geographically restricted subset of the recognized species and genera, limited to the areas above mentioned. Those studies included only a small number of species from African coasts, South America and Indian Ocean and did not redefine the complex genus Arius  ZBK  . The results obtained by Kailola (1990a) are essentially repeated in Kailola (2004) and the results obtained by Betancur-R. & Mejía (2000) are presented in Betancur-R. et al. (2004), but only part of the information contained in Betancur-R. (2003) is included in Betancur-R. & Acero (2004). In an unpublished Ph.D. study, Marceniuk (2003) included the largest number of ariid species ever assembled from different geographic areas of the world and used a vast array of morphological characters to study the systematics and phylogeny of the group.

The present work is based on the results obtained by Marceniuk (2003). All nominal genera are revised and redefined through exclusive osteological characters and a combination of internal and external morphological characters. Based on examination of the type-species the following genera are considered valid: Arius  ZBK  , Aspistor  ZBK  , Bagre  Cloquet 1816, Batrachocephalus  ZBK  , Brustiarius  ZBK  , Cathorops  , Cephalocassis  ZBK  , Cinetodus  ZBK  , Cochlefelis  ZBK  , Cryptarius  ZBK  , Doiichthys  ZBK  , Galeichthys  ZBK  , Genidens  ZBK  , Hemiarius  ZBK  , Ketengus  ZBK  , Nedystoma  ZBK  , Nemapteryx  ZBK  , Neoarius  ZBK  , Netuma  , Notarius  ZBK  , Osteogeneiosus  ZBK  , Pachyula  ZBK  and Sciades  . The genera Plicofollis  ZBK  and Potamarius  ZBK  are considered valid through examination of species morphologically similar to the type-species. Representative material of Amissidens  ZBK  species-type was not examined and the genus is recognized exclusively on the basis of evidences presented by Kailola (2004). Amphiarius  , Carlarius  and Potamosilurus  are described as new genera. The nominal genera Ailurichthys  ZBK  , Anemanotus  ZBK  , Ariopsis  ZBK  , Bagre  Oken 1817, Felichthys  ZBK  , Glanis  ZBK  , Guiritinga  ZBK  , Hemipimelodus  ZBK  , Hexanematichthys  ZBK  , Pseudarius  ZBK  , Sciadeichthys  ZBK  , Sciadeops  ZBK  , Selenaspis  ZBK  , Septobranchus  ZBK  and Stearopterus  ZBK  are considered junior synonyms based on examination of the type-species and Leptarius  ZBK  and Pararius  ZBK  are considered junior synonyms based on examination of the type-species not cleared and stained. Ariodes  and Tetranesodon  ZBK  are considered junior synonyms based on data presented by Kailola (2004). Breviceps  ZBK  Swainson, 1838 and Mystus  ZBK  Gray, 1854 are junior homonyms of names available for the genus-group and thus rejected. Catastoma  ZBK  and Sarcogenys  ZBK  are considered nomina nuda and designated as synonyms of Netuma  , in agreement with Kailola (2004). Glanide is not a Latin name and was not considered. The nominal genera Ancharius  ZBK  , Paradiplomystes  ZBK  and Tachysurus  ZBK  , previously included in the family are not recognized as members of the Ariidae  .

The new classification proposed contains many modifications in relation to previous ones and the status of nominal genera as well as species composition are in many instances entirely changed. The species treated as sedis mutabilis (see New classification of the Ariidae  ) were not examined and their inclusion in the respective genera is preliminary. In this section conflicts between the new and previous classifications are discussed and brief considerations about former concepts of genera and species composition are made. Classifications proposed by Kailola (2004), Betancur-R. & Acero (2004) and Betancur-R. et al. (2004) based on recognition of genera as monophyletic units as well as more recent and historically important classifications are discussed.

The genera Amissidens  ZBK  and Cryptarius  ZBK  are considered valid and the species included in them are those recognized by Kailola (2004). Previously C. truncatus  was included in Arius  ZBK  (Burgess, 1989; Kottelat et al, 1993; Rainboth, 1996; Martin-Smith & Tan, 1998; Kailola, 1999; Tan & Ng, 2000; Kailola, 2000a; Ng, 2003) and C. daugueti  in Hemipimelodus  ZBK  ( Désoutter, 1977; Rainboth, 1996).

Amphiarius  is a new genus established to accommodate A. rugispinis  and A. phrygiatus  previously included in a distinct genus not formally named by Marceniuk (2003). In Marceniuk & Ferraris (2003) these two species were preliminary included in Arius  ZBK  , following Taylor & Menezes (1977), Burgess (1989), Cervigôn (1992), Le Bail et al. (2000), Camargo & Isaac (2001) and Acero (2003), decision also chosen by Kailola (2004) who examined only A. rugispinis  , but suggested that they could be part of a separate genus she never designated. Betancur-R. & Acero (2004), however, considered A. rugispinis  to belong in Notarius  ZBK  based on mitochondrial information.

One of the major problems in ariid systematics has been the delimitation of the genus Arius  ZBK  . It has been considered a very inclusive genus where ariid species not clearly defined were preliminary accommodated in the past. Kailola (1999) and Acero (2003) recognized Arius  ZBK  as a non monophyletic assemblage pointing out the enormous difficulty in defining the genus. Recent attempts to bring ariid generic concepts to a better understanding using phylogenetic systematics (Kailola, 2004; Betancur-R. & Acero, 2004) did not consider all the species tentatively included in Arius  ZBK  to circumscribe the genus or to define its monophyletic condition. As defined in the present study Arius  ZBK  is senior synonym of Ariodes  and Pseudarius  ZBK  and include twenty one species occurring from eastern Africa and western Madagascar to south and southeast Asia. All the included species can be easily told apart from the remaining ariid species occurring in the Americas, New Guinea and Australia by the typical bifurcation of the lateral line at the caudal region reaching the bases of the upper and lower caudal-fin lobes (versus lateral line simple, not bifurcated at the caudal region reaching or not the bases of the upper caudal-fin lobe) except for the species of the genus Bagre  in which, however, there are one pair of mental barbels (versus two pairs in the Arius  ZBK  species). Arius  ZBK  species are different from ariid species belonging to Indian Ocean genera by having the adipose fin of moderate length, about half as long as the anal fin (versus adipose fin short, less than half the length of the anal fin, characteristic of Netuma  and Plicofollis  ZBK  ), maxillary barbels present and always developed (versus maxillary barbels absent in Batrachocephalus  ZBK  and rudimentary in Ketengus  ZBK  ) and mental barbels present (versus mental barbels absent in Osteogeneiosus  ZBK  ). The apomorphic or plesiomorphic condition of these characters as well as monophyly of Arius  ZBK  will be discussed in Marceniuk & Menezes (in preparation). In the present work only morphological features that are useful to distinguish the species of Arius  ZBK  from the species of the remaining genera are emphasized.

In Aspistor  ZBK  we recognize A. luniscutis  and A. parkeri  . Betancur-R. & Acero (2004) without examining the type-species, considered Aspistor  ZBK  as junior synonym of Notarius  ZBK  , admitting that Aspistor parkeri  (= Arius quadriscutis  ZBK  ) would be the basal most species within Notarius  ZBK  , a condition that would justify its recognition as subgenus. Kailola (2004), based on data in Acero & Betancur-R. (2002a, 2002b) and Aguilera & de Aguilera (2004), recognized Aspistor  ZBK  as valid and included in it eight species from South and Central America and one from New Guinea. In her phylogenetic analysis she examined only Arius hardenbergi  ZBK  Kailola, 2000 considered in the present study to belong in Hemiarius  ZBK  . The remaining species included by Kailola (2004) in Aspistor  ZBK  , except A. luniscutis  and A. parkeri  are herein considered to belong in Notarius  ZBK  or Sciades  . In older classifications A. luniscutis  and A. parkeri  are Arius  ZBK  species (Taylor & Menezes, 1977; Burgess, 1989; Cervigôn, 1992; Le Bail et al, 2000; Camargo & Isaac, 2001; Acero, 2003).

Bagre  Cloquet, 1816 is senior synonym of Bagre  Oken, 1817, Glanis  ZBK  , Stearopterus  ZBK  , Breviceps  ZBK  non Merrem, 1820, Felichthys  ZBK  (replacement for Breviceps  ZBK  ), Ailurichthys  ZBK  , Mystus  ZBK  non Scopoli, 1777 and Anemanotus  ZBK  following previous classifications (Castro-Aguirre et al., 1999; Marceniuk & Ferraris, 2003; Kailola, 2004). Very little changes have occurred in the species composition of the genus. In older publications the species were included either in Felichthys  ZBK  (Jordan & Evermann, 1896; Eigenmann, 1912; Meek & Hildebrand, 1923; Fowler, 1951) or in Ailurichthys  ZBK  ( Günther, 1864; Jordan & Gilbert, 1883; Eigenmann & Eigenmann, 1890; Regan, 1907) with the list of species included remaining essentially the same except for those herein considered as junior synonyms.

Batrachocephalus  ZBK  , Ketengus  ZBK  and Osteogeneiosus  ZBK  are considered valid as previously recognized by several authors (Jayaram & Dhanze, 1978; Jayaram, 1982, 1884; Jayaram & Dhanze, 1986; Talwar & Jhingran, 1991; Kottelat et al., 1993; Manilo & Bogorodsky, 2003; Kailola, 2004). The condition of monospecific genera is maintained due to the presence of a large number of exclusive characters in the respective type-species.

Brustiarius  ZBK  is considered senior synonym of Pararius  ZBK  and includes B. nox  , B. proximus  and B. solidus  . Kailola (2004) recognized the monophyly of the genus, but did not include B. proximus  that was considered to belong in Netuma  , whereas Pararius  ZBK  was designated junior synonym of Netuma  . In previous classifications Brustiarius  ZBK  was considered junior synonym or subgenus of Arius  ZBK  in which the species now in Brustiarius  ZBK  were included (Burgess, 1989; Kailola, 1990b, 1999, 2000b; Allen, 1991; Allen et al., 1992; Larson & Williams, 1997; Hutchins, 2001).

The ariid species from the African west coast formerly included in Arius  ZBK  (Fowler, 1936; Taylor, 1986, 1990; Burgess, 1989; Daget, 1992) are allocated into a new genus named Carlarius  .

The species composition of Cathorops  proposed by Marceniuk & Ferraris (2003) is maintained, including C. dasycephalus  , recently referred to Arius  ZBK  (Bussing & Lopez, 1994; Kailola & Bussing, 1995; Betancur-R., 2003) or to Ariopsis  ZBK  (Nelson et al., 2004). Evidences that Cathorops  is monophyletic are presented by Marceniuk (1997) based on the study of most species of the genus and this was confirmed by Betancur-R. et al. (2004) and Kailola (2004) although examining a restricted number of species.

Cephalocassis  ZBK  is recognized as senior synonym of Hemipimelodus  ZBK  and includes C. bleekeri  , C. borneensis  , C. manillensis  and C. melanochir  . Kailola (2004) agrees with the synonymy, but considers Cephalocassis  ZBK  represented only by C. borneensis  and C. melanochir  . C. bleekeri  is included in Nemapteryx  ZBK  by Kailola (2004). Hemipimelodus  ZBK  , however, is considered valid by Désoutter (1977), Jayaram & Dhanze (1978), Jayaram (1982), Burgess (1989) and Roberts (1989).

Cinetodus  ZBK  and Pachyula  ZBK  are considered valid based on characters present in the respective type-species. Cinetodus  ZBK  is represented by C. carinatus  and C. froggatti  and Pachyula  ZBK  by P. crassilabris  and P. conorhynchus  . Kailola (2004) recognized Cinetodus  ZBK  and Pachyula  ZBK  synonyms and included all the species mentioned above in Cinetodus  ZBK  , but in Kailola’s phylogenetic analysis Cinetodus  ZBK  is considered paraphyletic not justifying the inclusion of the species in a single genus and contradicting this synonymy. The species herein included in Cinetodus  ZBK  and Pachyula  ZBK  were considered sister-species by Kailola (2004), a condition that would make the two genera valid (Marceniuk, 2003). The nominal genus Tetranesodon  ZBK  considered synonym of Cinetodus  ZBK  by Kailola (2004), is recognized by us as junior synonym of Pachyula  ZBK  .

Cochlefelis  ZBK  includes four species from southern New Guinea and northern Australia. The recognition of C. danielsi  and C. spatula  is in agreement with previous classifications (Roberts, 1978; Allen, 1991; Kailola, 2004). However, including C. dioctes  formerly considered to belong in Arius  ZBK  (Ng, 2003) or in Hemiarius  ZBK  (Kailola, 2004) and C. insidiator  , previously in Hemiarius  ZBK  (Kailola, 2004), represents a new arrangement. Kailola (2004) also included Arius burmanicus  ZBK  in Hemiarius  ZBK  considered by us to belong in Arius  ZBK  .

Nedystoma dayi  and Doiichthys novaeguineae  ZBK  have been considered sister-species by Marceniuk (2003), a conclusion also reached by Kailola (2004) who considered Nedystoma  ZBK  senior synonym of Doiichthys  ZBK  . In the present paper the two genera are not considered synonyms. The respective type-species possess a large number of exclusive characters justifying their monospecific condition as previously recognized (Roberts, 1978; Burgess, 1989; Allen, 1991).

Galeichthys  ZBK  includes G. ater  ZBK  and G. felis  from South Africa and G. peruvianus  ZBK  from the Peruvian coast in the Pacific Ocean, following previous classifications (Hildebrand, 1946; Taylor, 1986, 1990; Pequeño, 1989; Bianchi et al, 1993; Kailola & Bussing, 1995; Chirichigno & Vélez, 1998, Castro-Aguirre et al, 1999; Marceniuk& Ferraris, 2003; Heemstra & Heemstra, 2004; Nelson et al., 2004; Kailola, 2004). The species from east and west American coasts attributed to Galeichthys  ZBK  by Regan (1907) and Meek & Hildebrand (1923) are included in Cathorops  , Notarius  ZBK  and Sciades  .

Genidens  ZBK  was established and remained until very recently as a monospecific genus. As defined in this study it is senior synonym of Guiritinga  ZBK  and also includes Genidens barbus  , G. planifions  and G. machadoi  ZBK  following Marceniuk & Ferraris (2003) and Marceniuk (2005a, 2005b). In previous classifications G. barbus  and G. planifions  were part of Netuma  (Figueiredo & Menezes, 1978; Higuchi et al., 1982; Burgess & Finley, 1996; Pequeño, 1997; López et al., 2002). Higuchi et al. (1982) questioned the inclusion of these species in Netuma  hoping that in future systematic studies the name Guiritinga  ZBK  would be resurrected. Apparently Higuchi et al. (1982) expectations motivated Kailola (2004) to recognize Guiritinga  ZBK  to accommodate Genidens barbus  and G. planifions  . Guiritinga  ZBK  is not recognized by Kailola (2004) as a monophyletic group.

Hemiarius  ZBK  is considered a valid genus for H. hardenbergi  , H. harmandi  ZBK  , H. stormii  , H. sumatranus  and H. verrucosus  . Kailola (2004) based on the examination of H. stormii  and two other species herein included in Cochlefelis  ZBK  ( C. dioctes  and C. insidiator  ) considered Hemiarius  ZBK  monophyletic. Hemiarius verrucosus  , Notarius grandicassis  and Sciades sona  were additionally included in Hemiarius  ZBK  by Kailola (2004).

Our analysis indicates that Nemapteryx  ZBK  is monospecific. Kailola (2004) includes in this genus five species herein allocated to the genera Arius  ZBK  , Neoarius  ZBK  and Cephalocassis  ZBK  . As revealed by the topology of the consensus cladogram presented by Kailola (2004), the genus cannot be considered monophyletic.

Neoarius  ZBK  is resurrected and includes N. augustus  , N. berneyi  , N. graeffei  , N. midgleyi  and N. pectoralis  all restricted to southern New Guinea and northern Australia. With exception of N. augustus  , included by Kailola (2004) in Nemapteryx  ZBK  , the other species were considered by her to belong in Ariopsis  ZBK  .

Bagre thalassinus  Rüppell, 1837 distributed from eastern Africa, south and southeast Asia to New Guinea and northern Australia (Kailola, 1986) is the type-species of Netuma  . As defined by Kailola (2004) Netuma  included N. bilineatus  , Arius proximus  ZBK  (herein included in Brustiarius  ZBK  ) and N. thalassinus  and is not monophyletic. In the present work only the species from the Indo-Pacific should be included in Netuma  following Taylor (1986), Hutchins (2001) and Kailola (2004). The inclusion of species from the Western South Atlantic belonging to Genidens  ZBK  (Figueiredo & Menezes, 1978; Higuchi et al., 1982) and from the eastern and western American coasts belonging to Notarius  ZBK  and Sciades  (Jordan & Evermann, 1898; Gilbert & Starks, 1904; Starks, 1906; Meek & Hildebrand, 1923) is not corroborated by us. Catastoma  ZBK  and Sarcogenys  ZBK  are considered nomina nuda and junior synonyms of Netuma  as demonstrated by Kailola (2004).

Notarius  ZBK  is valid (Marceniuk & Ferraris, 2003; Betancur-R. & Acero, 2004) in disagreement with Kailola (2004) who recognizes Notarius  ZBK  as a junior synonym of Hemiarius  ZBK  . The species composition of the genus, however, differs from that presented by Betancur-R. & Acero (2004) by not including Amphiarius rugispinis  and Aspistor parkeri  (= Arius quadriscutis  ZBK  ) and adding Notarius osculus  , considered by Betancur-R. & Acero (2004) as of uncertain status and included in previous classifications in Arius  ZBK  (Burgess, 1989; Bussing & López, 1994; Kailola & Bussing, 1995; Acero & Betancur-R., 2002a) or Hexanematichthys  ZBK  (Marceniuk & Ferraris, 2003). The nominal genus Sciadeops  ZBK  , recognized as junior synonym of Sciades  by Kailola (2004), is considered junior synonym of Notarius  ZBK  .

Kailola (2004) described Plicofollis  ZBK  in which P. argyropleuron  , P. crossocheilos  , P. dussumieri  , P. layardi  (= Arius tenuispinis  ZBK  ), P. nella  and P. polystaphilodon  were included. We added into the genus P. platystomus  that share with the other species of Plicofollis  ZBK  a unique combination of characters considered apomorphic by Marceniuk (2003).

Two species entirely confined to the freshwaters of North and Central America were allocated in Potamarius  ZBK  , a genus originally described by Hubbs & Miller (1960). Its type-species was previously included in Conorhynchus  ZBK  of the family Pimelodidae  (Meek, 1904; Regan 1907). Potamarius grandoculis  was considered to belong in Hexanematichthys  ZBK  by Figueiredo & Menezes (1978) and in Arius  ZBK  by Burgess (1989), but its inclusion in Potamarius  ZBK  is in agreement with previous classifications proposed by Marceniuk & Ferraris (2003) and Marceniuk, (2005b).

Potamosilurus  is herein created for the species occurring exclusively in freshwater in New Guinea. P. coatesi  , P. latirostris  , P. macrorhynchus  and P. robertsi  are found in south-draining rivers and P. velutinus  in north-draining rivers of New Guinea. With exception of P. macrorhynchus  , recognized as incertae sedis, the remaining species were included in Ariopsis  ZBK  by Kailola (2004).

Hexanematichthys  ZBK  , Sciadeichthys  ZBK  , Selenaspis  ZBK  , Ariopsis  ZBK  and Leptarius  ZBK  are synonyms of Sciades  , but have been recently considered either valid or placed in the synonymy of genera other than Sciades  (Roberts, 1989; Kailola, 1990a; Castro-Aguirre et al., 1999; Acero, 2003; Marceniuk & Ferraris, 2003; Betancur-R. et al., 2004; Kailola, 2004). In this study the species belonging to Ariopsis  ZBK  (Acero, 2003; Kailola, 2004, in part), Hexanematichthys  ZBK  and Selenaspis  ZBK  (Acero, 2003; Betancur-R. et al., 2004; Kailola, 2004) and Arius  ZBK  (Betancur-R. et al., 2004, in part) are all included in Sciades  based on the possession of the following exclusive characters within the Ariidae  : otic capsules little developed; space between transcapular process and otic capsule very wide; temporal fossa very reduced or entirely closed; subvertebral process indistinct or little differentiated. Sciades  was considered valid by Castro-Aguirre et al. (1999), whereas Marceniuk & Ferraris (2003) recognized this genus as probably senior synonym of Hexanematichthys  ZBK  . Kailola (2004) recognized Sciades  based exclusively on examination of the type-species, considered by her sister-species of Hemiarius hardenbergi  , additionally adding into the genus S. couma  , S. herzbergii  ZBK  , S. dowii  , S. parkeri  ZBK  , S. passany  , S. proops  and Notarius troschelii  .