Ordovician cephalopods from the Valongo Formation are among the first Ordovician fossils described
from the Iberian Peninsula. The present review shows a lower taxonomical diversity than previously reported.
Large endocerids and orthocerids are abundant in beds of early Oretanian (Middle Darriwilian) age, and
orthocerids and some tarphycerids occur in strata of early Dobrotivian (Late Darriwilian) age. Despite the
poor preservation in shales and the absence of internal structures, five different forms of longicones were
identified, remaining them in open nomenclature. Tarphycerids are better recognizable and belong to the
late Darriwilian forms Trocholites fugax and T. cf. depressus, with the former species recorded over a wide
area of Ibero-Armorica and Bohemia, and the second related to a Baltic form. The occurrence of the genus
Trocholites among Circumpolar Gondwana cephalopod faunas is consistent with the sporadic transfer of
warm to temperate water masses southwards from the vicinity of Baltica, through a period of climatic
disturbances affecting the southern hemisphere during the late Darriwilian
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