Many current debates about biodiversity and large-scale evolution have identified the need for comprehensive species inventories. Such species lists may be incomplete because more collecting is needed, or because of errors by systematists. Empirical studies show that error rates are high, as much as 30–50% for many living and fossil groups. A clear requirement is skilled systematists, and more of them; but who does the best work? An empirical investigation of the 321 authors who named all 1400 species of dinosaurs since 1824 shows that prolific authors do worse than authors who name only a few dinosaurs, and the key difference is between the 147 authors who named only one species, and the 174 who named two or more. The most prolific author was Othniel Marsh, who named 98 species of dinosaurs (including 80 non-avian dinosaurs and 18 Mesozoic birds), but only 35 (36%) of his names are currently regarded as valid. The poor showing by prolific authors is not a result of their working at different times over the last two centuries, nor on dinosaurs of a particular age, body size, or quality class, nor that their work has been over-revised, but most likely because many prolific authors of dinosaur species names have been too interested in splitting species. Current tougher refereeing standards and international communication should continue to improve standards in naming new taxa.