| Diagnosis |
Hisonotus oliveirai is diagnosed from all species ofHisonotus, except H. insperatus, H. luteofrenatus and H. paresi, by having odontodes forming longitudinally aligned rows (one odontode after the other, but not necessarily forming parallel series) on head and trunk (vs. odontodes not forming longitudinally aligned rows). It differs also from all congeners except H. insperatus, H. luteofrenatus, H. paresi, and H. piracanjuba, by the possession of a pair of rostral plates at the tip of the snout (vs. a single rostral plate). In addition, it further differs from all congeners except H. bockmanni, H. chromodontus, H. insperatus, H. luteofrenatus, and H. paresi by having a functional v-shaped spinelet (vs. spinelet non-functional, square-shaped, or absent). It can be separated from H. bockmanni and H. paresi by lacking contrasting dark geometric spots on the anterodorsal region of the body (vs. presence); from H. insperatus by having small, inconspicuous odontodes forming rows on the head and trunk (vs. large, conspicuous odontodes forming rows on the head and the trunk), head depth 51.6?59.2% HL (vs. 44.3?48.7% HL) and suborbital depth 20.9?25.5% HL (vs. 16.6?20.1% HL); from H. luteofrenatus by having caudal peduncle depth 10.8?12.5% SL (vs. 8.9?10.2% SL) and snout length 46.9?52.2% HL (vs. 67.0?75.3% HL); from H. paresi by a having head depth 51.6?59.2% HL (vs. 42.4?47.7% HL), 11-18 premaxillary teeth (vs. 6?10), and 11-15 dentary teeth (vs. 4?7); from H. piracanjuba by having caudal peduncle depth 10.8?12.5% SL (vs. 8.3?9.5% SL), and snout length 46.9?52.2% HL (vs. 67.7?72.7% HL) (Ref. 95507). |