Plautianus' zebras: A Roman expedition to East Africa in the early third century

The kleptocratic supremacy of the praetorian prefect C. Fulvius Plautianus (PIR2 F 554) was felt throughout the city of Rome, the Empire and (according to one author) even beyond the imperial frontiers. Indeed, for the senatorial historian Dio Cassius, there was no more picturesque demonstration of Plautianus' acquisitiveness than his seizure of strange striped horse-like creatures from ‘islands in the Erythraean Sea’. The passage, as preserved in the text of Xiphilinus' Epitome, reads as follows (Dio Cass. 76[75].14.3):
καὶ τέλος ἵππους Ἡλίῳ <ἱεροὺς> τιγροειδεῖς ἐκ τῶν ἐν τῇ Ἐρυθρᾷ θαλάσσῃ νήσων, πέμψας ἑκατοντάρχους, ἐξέκλεψεν·
In the end he even stole tiger-like horses <sacred> to Helios from the islands in the Erythraean Sea, having sent some centurions to carry out the task.