FIGURE 13 in Potamotrygon rex, a new species of Neotropical freshwater stingray (Chondrichthyes: Potamotrygonidae) from the middle and upper rio Tocantins, Brazil, closely allied to Potamotrygon henlei (Castelnau, 1855)

FIGURE 13. Skeletal features of Potamotrygon rex, sp. nov., from radiographs, in dorsoventral view. A) Head region of MZUSP 120354; B) Head region of MZUSP 120353; C) Close-up of specimen in A; D) Base of tail region, showing distribution and development of dermal denticles and thorns (paratype, MZUSP 120369). Abbreviations: aac, anterior angular cartilage; ao, antorbital cartilage; apr, anterior segment of propterygium; fpf, frontoparietal fontanelle; hyo, hyomandibula; Mc, Meckel's cartilage; no, nasal opening (nasal aperture); pac, posterior angular cartilage; pop, postorbital process; pq, palatoquadrate; pro, propterygium; prp, preorbital process; psc, prespiracular cartilage; sp, supraorbital process.Published as part of De Carvalho, Marcelo R., 2016, Potamotrygon rex, a new species of Neotropical freshwater stingray (Chondrichthyes: Potamotrygonidae) from the middle and upper rio Tocantins, Brazil, closely allied to Potamotrygon henlei (Castelnau, 1855), pp. 537-565 in Zootaxa 4150 (5) on page 552, DOI: 10.11646/zootaxa.4150.5.2, http://zenodo.org/record/26129