Two other features with ambiguous distributions that may possibly also represent elopomorph synapomorphies are the presence of distinct, strong ligaments connecting the anterior surface/anterior cartilage of the autopalatines and/or dermopalatines and the maxillae and/ or premaxillae (160: 0 [right arrow] 1) and the presence of an ossified interhyal (223: 0 [right arrow] 1) (see 'Clade C1' above).
As mentioned above, there are two features with ambiguous distributions that might possibly constitute synapomorphies of the osteoglossomorphs examined: the absence of distinct, strong ligaments connecting the anterior surface/anterior cartilage of the autopalatines and/or dermopalatines to the maxillae and/or premaxillae (160: 1 [right arrow] 0) and the absence of an ossified interhyal (223: 1 [right arrow] 0) (see 'Clade C1').
Six morphometric characters were studied, five in the triangular region (tr) that articulates with the nasal, premaxillae
, prenasal, and vomer: length of the triangle (ML), height of the triangle (MH), width from the lateral surface of the triangle to the medial margin of the facet (fv) for articulation with the vomer (MW), and height (MVH) and width (MVW) of the facet.
He performed statistical analyses on the size of inferior pharyngeal clusters of parrotfish and large-eyed bream premaxillae
(Masse 1989:498-515) to test this hypothesis.
The alary processes of the premaxillae
are vertical in all taxa and most have a deep pars facialis of the maxilla (like that of E.
Peculiar mesial interdigitations between premaxillae.
Prominent, roughly triangular anterolateral processes of premaxillae.
The obliquely truncated premaxillae are markedly deflected at their expanded extremity and each contains 4 or 5 teeth.
Nasals and premaxillae separated by 36-56% of total length of rostrum.
Considering the morphological studies all the specimens captured in Uranga, Pergamino and those obtained from the laboratory colonies showed the following states of qualitative characters: a) nasal projected rostrally, overhanging the premaxillae
and hiding the incisors in dorsal view; b) conspicuous interorbital constriction, frontals divergent caudally, with crested and sharp lateral edges; c) zygomatic plate high, not robust, with its dorsal margin shorter and slightly rounded in its antero-dorsal end; d) mesopterygoid fossa squared off, with a well-defined medial palatine process of consistent occurrence across individuals; e) a long and slender coronoid process, with its end completely curved caudally.
Characters studied without reference to region were: distribution of denticles on the dorsal surface of the rostrum measured from the distal tip (DZ); length from distal tip where denticles are absent from the ventral mid-line (DVS); length from the distal tip to the distal extremity of t he prenasal (P); length from tip where fused premaxillae
divide into separate bones (VSPM); and presence or absence of denticles on the prenasal.
6 mm); postorbital region depressed; sagittal and lambdoidal crests poorly developed; premaxillae
completely separated; upper incisors and canines separated by a short diastema; upper canines with a well developed external cingulum; P2 and P3 united and separated from P4 by a short diastema; P3 alveoli less than P2 and smaller than half the size of P4; P4 antero-posteriorly expanded; molars ectolophs W-shaped; M2 larger than M1 and M3; premolars forming a continuous row from the canine to the molar.