ABSTRACT
Neurocranium and Anterior Vertebrae 56. Ventral projection of mesethmoid cornua. Contrary to all other catfish
examined [State 0: e.g. Fig. 3.63], in specimens of genera Cetopsis and Hemicetopsis examined the mesethmoid cornua present a well-developed, ventral, vertical projection of laminar bone [State 1: e.g. Fig. 3. 46]. — CS-0: Mesethmoid cornua not presenting ventral, vertical projection
of laminar bone (all genera not in other CS)
57. Cartilage of mesethmoid (inspired from Friel, 1994). Contrary to all other catfish examined [State 0: e.g. Fig. 3.67], the three genera of CS-1 present a small, Y-shaped cartilage on the posteromesial surface of the mesethmoid [State 1]. — CS-0: M esethm oid not presenting Y-shaped cartilage on
posteromesial surface (all genera not in other CS) — CS-1: Mesethmoid presenting small, Y-shaped cartilage on
1986). As stated by Lundberg and McDade (1986), plesiomorphically catfish lack major ventral processes on the lateral surface of the mesethmoid [State 0: e.g. Fig. 3.66]. In genera of CS-1, this bone exhibits two well-developed, ventrolateral processes mainly directed laterally, but also anteriorly, which are significantly posterior to the mesethmoid comua [State 1]. — CS-0: Mesethmoid lacks ventrolateral processes (all genera not in
situation for catfish, in which the mesethmoid lacks major, deep dorsal concavities [State 0: e.g. Fig. 3.67], in specimens of Pangasius examined, this bone exhibits two well-developed, dorsolateral crests, which delimit a well-defined, deep dorsomesial concavity [State 1]. — CS-0: Mesethmoid lacks major, deep dorsomesial concavitiy (all
genera not in other CS) — CS-1: Mesethmoid exhibits well-defined, deep dorsomesial concavity
dorsolateral projections of the mesethmoid [State 0: e.g. Fig. 3.63] but in genera of CS-1, this bone exhibits prominent dorsolateral projections of laminar bone, with its dorsal surface thus markedly larger than its ventral surface [State 1: e.g. Fig. 3.25]. — CS-0: Mesethmoid lacks major dorsolateral projections of laminar
bone (all genera not in other CS) — CS-1: Mesethmoid with prominent dorsolateral projections of
61. Highly developed ventromesial crest of mesethmoid (character inspired from Schaefer, 1997). Contrary to the plesiomorphic situation for catfish in
which the mesethmoid lacks major ventral crests [State 0: e.g. Fig. 3.89], in specimens examined of the four genera of CS-1 this bone exhibits a highly developed, somewhat roundish, prominent ventromesial crest [State 1]. — CS-0: Mesethmoid lacking highly developed ventromesial crest (all
genera not in other CS) — CS-1: Mesethmoid exhibiting highly developed ventromesial crest
(Loricaria, Hypoptopomaf Lithoxus, Astroblepus) 62. Well-developed cartilage between ventral surface of mesethmoid and premaxilla
(character inspired from Schaefer, 1997). Contrary to the plesiomorphic situation for catfish in which there is no well-developed cartilage between the mesethmoid and the premaxilla [State 0: e.g. Fig. 3.64], siluriforms of CS-1 exhibit a large, well-developed cartilaginous structure between these two bones for articulation between them [State 1]. — CS-0: No well-developed cartilage between mesethmoid and
premaxilla (all genera not in other CS) — CS-1: Well-developed cartilage between mesethmoid and premaxilla
(Loricaria, Hypoptopoma, Lithoxus, Astroblepus) 63. Ligamentous connection between ventral surface of mesethmoid and premaxilla
(character inspired from Schaefer, 1997). Contrary to the plesiomorphic single ligamentous connection between the mesethmoid and the premaxilla [State 0: e.g. Fig. 3.66], the loricariids examined present two well-defined ligaments between these two structures [State 1]. — CS-0: Single ligamentous connection between ventral surface of
mesethmoid and premaxilla (all genera not in other CS) — CS-1: Presence of two well-defined ligaments between ventral
64. Prominent dorsomesial crest of mesethmoid. In the plesiomorphic siluriform configuration, the mesethmoid lacks major dorsomesial crests [State 0: e.g. Fig. 3.67] but in Leptoglanis this bone exhibits a prominent, anteroposteriorly elongated, dorsomesial crest [State 1: e.g. Fig. 3.17]. — CS-0: Mesethmoid lacks major dorsomesial crests (all genera not in
other CS) — CS-1: M esethm oid exhibits prom inent dorsom esial crest
(LeptoglaniS 65. Layer of cartilage-like tissue (character inspired from de Pinna and Vari, 1995).
