Key to Old World genera and subtribes of Ariinae

12a. Two pairs of accessory tooth plates … (incertae sedis) ............................................................................................................. Netuma 12b. One pair accessory tooth plates .............................................................................................................................................................. 13 13a. Teeth in premaxilla cuspidate; teeth in dentary spatulate or cuspidate; autopalatine depressed and mesially angled in its anterior third .................................................................................................................................................................................................... 14 13b. Teeth in premaxilla acute; teeth in dentary acicular; autopalatine cylindrical ............................................................................... 15 14a. Maxillary barbel absent; lateral ethmoid contacts frontal … ( Ariina)................................................................... Batrachocephalus 14b. Maxillary barbel present; lateral ethmoid not contacting frontal … ( Ariina) ................................................................... Ketengus

15a. Maxillary barbel osseous; mental barbels absent … ( Ariina) ..................................................................................... Osteogeneiosus

15b. Maxillary barbel fleshy; mental barbels present .................................................................................................................................. 16

16a. Fenestra delimited by lateral ethmoid and frontal distinct and very large; posterior process of cleithrum very short; ventral tip of subvertebral process spatulate ...................................................................................................................................................... 17

16b. Fenestra delimited by lateral ethmoid and frontal indistinct to moderately wide; posterior process of cleithrum moderately long to very long; ventral tip of subvertebral process split or acute ................................................................................................ 22

17a. Tooth band on fifth ceratobranchial very small; dorsal processes of upper (pharyngeal) tooth plate very long and conspicuous, connected by bony blade ................................................................................................................................................................. 18

17b. Tooth band on fifth ceratobranchial very large to moderate; dorsal processes of upper (pharyngeal) tooth plate very short or absent, not connected by bony blade .................................................................................................................................................... 19

18a. Accessory tooth plates absent; premaxilla wide and moderately long, its width more than three times its length; upper (pharyngeal) tooth plate very long and narrow, its width more than four times its length … ( Doiichthyina) .................................... .......................................................................................................................................................................................................... Nedystoma

18b. Accessory tooth plates present; premaxilla as long as wide; upper (pharyngeal) tooth plate long and narrow, its width three times its length … ( Doiichthyina) ............................................................................................................................................ Doiichthys

19a. Fenestra delimited by parieto-supraoccipital, pterotic and sphenotic present; ventral crest of hyomandibula absent; accessory crest connecting transverse and median crests associated with neural spine of fourth vertebra present ....................... 20

19b. Fenestra delimited by parieto-supraoccipital, pterotic and sphenotic absent; ventral crest of hyomandibula present; accessory crest connecting transverse and median crests associated with neural spine of fourth vertebra absent ......................... 21

20a. Temporal fossa moderate to very large; lateral line not bifurcated at caudal region, extending to dorsal caudal-fin lobe; superficial ventral ossification of Weberian apparatus keeled … ( Ariina) ............................................................................ Cephalocassis

20b. Temporal fossa very reduced; lateral line bifurcated at caudal region, extending to dorsal and ventral caudal-fin lobes; superficial ventral ossification of Weberian apparatus regularly arched … ( Ariina) ....................................................... Hemipimelodus

21a. Dorsal-fin spine without filament; optic foramen moderately large; posterior cranial fontanel wide and long (Marceniuk et al. 2012: fig. 2B) … ( Ariina) ...................................................................................................................................................... Hemiarius

21b. Dorsal-fin spine prolonged into a filament; optic foramen very reduced; posterior cranial fontanel very wide and long (Marceniuk et al. 2012: figs 3A, 5B) … ( Doiichthyina) ................................................................................................... Nemapteryx

22a. Cleithrum lateral face very narrow; teeth on dentary restricted to mesial two-thirds; anterior portion of anterior cranial fontanel not delimited by dorsal expansion of orbitosphenoid; vomer arrow shaped … ( Ariina) .................................. Cryptarius

22b. Cleithrum lateral face moderately wide; teeth on dentary restricted to mesial one-third; anterior portion of anterior cranial fontanel partially or totally delimited by dorsal expansion of orbitosphenoid; vomer variable, but not arrow shaped ....... 23

23a. Posterior process of cleithrum very long, equal to vertical length of lateral face of cleithrum; ventral surfaces of parapophyses of fifth and sixth vertebrae conspicuously concave; anterior and posterior portions of basioccipital lateral process equally developed .................................................................................................................................................................................................... 24

23b. Posterior process of cleithrum very short to moderately long, less than one-third to about one-half vertical length of lateral face of cleithrum; ventral surfaces of parapophyses of fifth and sixth vertebrae straight; posterior portion of basioccipital lateral process extending further laterally than anterior portion .......................................................................................................... 26

24a. Premaxilla narrow and very long, its length two to three times in width; Müllerian ramus slender … ( Doiichthyina) ........... ..................................................................................................................................................................................................... Paracinetodus

24b. Premaxilla very wide and short, as long as wide; Müllerian ramus robust .................................................................................... 25

25a. Epioccipital not exposed dorsally; extrascapular subtriangular; accessory tooth plates present; upper (pharyngeal) tooth plate round, as wide as long … ( Doiichthyina) ...................................................................................................................... Cinetodus

25b. Epioccipital exposed dorsally; extrascapular subquadrangular; accessory tooth plates absent; upper (pharyngeal) tooth plate oval, its width twice in its length … ( Doiichthyina) ..................................................................................................... Pachyula

26a. Lateral line at caudal region bifurcated, reaching dorsal and ventral caudal-fin lobes; accessory tooth plates with molariform teeth (except Arius manillensis and Arius oetik); vomer anterior margin very pronounced and acute; extrascapular subrectangular ............................................................................................................................................................................................ 27

26b. Lateral line at caudal region not bifurcated, reaching dorsal caudal-fin lobe (except Neoarius hainesi); accessory tooth plates with needle-like teeth; vomer anterior margin weakly pronounced and serrated (except Potamosilurus and Neoarius hainesi); extrascapular subquadrangular or subtriangular (except Brustiarius and Pararius proximus) .................................................... 31

27a. Vomerine tooth plates present, entirely free from vomer; otolith posterior margin irregular; gas bladder lateral diverticula present; urohyal posterolateral processes as long as or longer than distal portion of bone … (incertae sedis) ............................ ............................................................................................................................................................................................................. Plicofollis

27b. Vomerine tooth plates absent; otolith posterior margin rounded; gas bladder lateral diverticula absent; urohyal posterolateral processes almost as long as distal portion of bone .............................................................................................................................. 28

28a. Fenestra delimited by lateral ethmoid and frontal very small or indistinct; second dorsal cleithral process posteriorly directed and parallel to posterior process; pterotic mesial border with parieto-supraoccipital as long as anterior border with sphenotic ...................................................................................................................................................................................... Kyataphisa

28b. Fenestra delimited by lateral ethmoid and frontal distinct and moderately wide; second dorsal cleithral process dorsally directed and parallel to first dorsal process; pterotic mesial border with parieto-supraoccipital longer than anterior border with sphenotic ..................................................................................................................................................................................................... 29

29a. Transcapular process depressed; bony blade connecting posterolateral processes of urohyal absent ................ Jayaramichthys

29b. Transcapular process cylindrical or columnar; bony blade connecting posterolateral processes of urohyal present ........... 30

30a. Orbitosphenoid and pterosphenoid lateral expansions as two short and wide leaf-like processes … ( Ariina) .......................... .................................................................................................................................................................................................. Betancurichthys

30b. Orbitosphenoid and pterosphenoid lateral expansions as slight projections with straight lateral faces … ( Ariina) .................. .................................................................................................................................................................................................................... Arius

31a. Posterior cranial fontanel absent ............................................................................................................................................................ 32

31b. Posterior cranial fontanel present ........................................................................................................................................................... 33

32a. Temporal fossa absent … ( Ariina) .............................................................................................................................. Hexanematichthys

32b. Temporal fossa present ............................................................................................................................................................................. 35

33a. Accessory tooth plates small, oval to rounded; connection between posterior process of exoccipital and Müllerian ramus by suture; autopalatine posterior portion very compressed … ( Doiichthyina) ................................................................. Bleekeriella

33b. Accessory tooth plates large, oval to subtriangular; connection between posterior process of exoccipital and Müllerian ramus by ligaments; autopalatine posterior portion only slightly compressed ......................................................................................... 34

34a. Lateral margins of orbitosphenoid progressively diverging anteriorly … ( Doiichthyina) ............................................... Pararius

34b. Lateral margins of orbitosphenoid uniformly parallel for entire length … ( Doiichthyina) ........................................ Brustiarius

35a. Accessory tooth plates absent … ( Doiichthyina) ........................................................................................................... Potamosilurus

35b. Accessory tooth plates present ................................................................................................................................................................ 36

36a. Posterior branches of mesethmoid very long, delimiting one-half length of anterior cranial fontanel; lateral expansions of orbitosphenoid and pterosphenoid absent … ( Doiichthyina) ....................................................................................... Aceroichthys

36b. Posterior branches of mesethmoid short, delimiting less than one-half length of anterior cranial fontanel; lateral expansions of orbitosphenoid and pterosphenoid present .................................................................................................................................... 37

37a. Accessory tooth plates large, oval to subtriangular ............................................................................................................................. 38

37b. Accessory tooth plates small, transversely elongate and narrow or oval to round ........................................................................ 39

38a. Margin of parieto-supraoccipital process contacting nuchal plate convex; lateral margins of orbitosphenoid progressively diverging anteriorly … ( Ariina) .......................................................................................................................................... Pseudosciades

38b. Margin of parieto-supraoccipital process contacting nuchal plate concave or notched; lateral margins of orbitosphenoid uniformly parallel for entire length … (incertae sedis) .................................................................................................................. Carlarius

39a. Accessory tooth plates narrow and oval to rounded … ( Doiichthyina) .......................................................................... Brustiarius

39b. Accessory tooth plates transversely elongate and narrow ................................................................................................................. 40

40a. Thirty-nine or more caudal vertebrae; mesial one-fourth of fourth epibranchial robust, almost as wide as long … ( Doiichthyina) .............................................................................................................................................................................. Cochlefelis

40b. Thirty-eight or fewer caudal vertebrae; mesial one-fourth of fourth epibranchial thin, its width about twice its length .......... ........................................................................................................................................................................................................................ 41

41a. Posterior cranial fontanel wide and long; articulation of autopalatine with lateral ethmoid slightly displaced to posterior portion of bone … ( Doiichthyina) ........................................................................................................................................... Papuarius

41b. Posterior cranial fontanel reduced to a small opening or relatively narrow and long; articulation of autopalatine with lateral ethmoid in middle of bone … ( Doiichthyina) ......................................................................................................................... Neoarius