| Diagnosis: |
Vertebrae: 110-116. This species can be distinguished from its congeners by the following set of characters: caudal fin with a mostly white ventral caudal lobe, its dorsal margin white at midline, and postventral margins broadly white; posterior margin of pectoral-fin broadly white; first dorsal fin with anterior margin also conspicuously white on its anterior half; differs from all species of the S. mitsukurii group with its short snout (vs. large), pectoral-fin free rear tips pointed (vs. rounded), dermal denticles lanceolate and unicuspid (vs. rhomboid and tricuspid); differs from S. cubensis by having a snout strongly pointed (vs. somewhat rounded), second dorsal-fin spine not reaching second dorsal-fin apex (vs. spine reaching second dorsal-fin apex), first dorsal fin with dark apex, but not as a black blotch (vs. distinct black blotch on both dorsal fins), pectoral fins with posterior margin broadly white (vs. narrowly white), in external morphometrics (Squalus albicaudus has a shorter first dorsal fin, anterior margin length 10.9%, 9.7%-11.2% TL vs. 11.6%, 11.6%-12.7% TL, shorter second dorsal fin, anterior margin length 9.2%, 8.8%-10.8% TL vs. 12.3%, 11.2%-11.6% TL, inner margin length 5.0%, 4.1%-5.2% TL vs. 5.6%, 5.5%-6.0% TL, more slender second dorsal-fin spine, width at base 0.9%, 0.6%-0.9% TL vs. 1.0%, 1.0%-1.2%, and clasper much more elongated, inner margin length 7.1%, 6.9%-7.7% TL vs. 8.0%, 3.3%-3.8% TL (Ref. 109601). |
