Prolagus

''Prolagus'' is an extinct genus of lagomorph. Over 20 species have been named, and the genus was abundant and widespread in Europe during the Neogene. However, by the end of the Middle Pleistocene, it was confined to a single species, the Sardinian pika (''P. sardus''), on the Corsica, Sardinia, and surrounding islands, where it survived into historical times. In North Africa and Western Asia, the genus is known from the Miocene and Pliocene may mean "before hares" or "primitive hares" (''pro-'' meaning "before" and ''lagos'' meaning "hare"). Its taxonomy is disputed, with it either being considered a member of the family Ochotonidae, which includes living pikas, or the only member of the family Prolagidae.

Taxonomy

''Prolagus'' was first named by Auguste Pomel in 1853. ''Prolagus'' has been considered by most taxonomists to be a member of the pika family Ochotonidae, but distinct from living pikas, which all belong to the genus '' Ochotona.'' Erbaleva in 1988 suggested it represented the only member of the monotypic family Prolagidae due to its distinct dental formula; this proposal was considered invalid by Nieves López Martínez, due to the fact that many mammal families have lineages with distinct dental formulae. N. López-Martínezbr>Paleobiogeographical history of ''Prolagus'', a European ochotonid (Lagomorpha)
Lynx, 32 (2001), pp. 215-231 However, many authorities such as the IUCN Red List and American Society of Mammalogists accept Prolagidae as valid. Analysis of a partial mitochondrial genome of ''Prolagus sardus'' suggests that it is more closely related to ''Ochotona'' than to Leporidae (which contains rabbits and hares), with an estimated divergence between ''Prolagus'' and ''Ochotona'' about 30 million years ago.

Description

''Prolagus'' is distinguished by a continuously growing dentition, a lack of a lower third molar, a trilobed second lower molar and unusually shaped premolars, with additional cusps in the lower third premolar. In comparison to modern pikas of the genus ''Ochotona,'' they have one less dorsal vertebra in the spinal column. Most species of ''Prolagus'' probably weighed around , similar to a living pika. A specimen with preserved soft-tissue is known from late Miocene aged deposits from Andance in France, which shows that its overall proportions, shape of the ears and lack of tail are similar to living ''Ochotona.''

Species

Over 20 species of ''Prolagus'' have been named.

Evolutionary history and ecology

''Prolagus'' likely evolved from the Oligocene-earliest Miocene genus '' Piezodus.'' The distribution of ''Prolagus'' between 20-8 million years ago extends from the Iberian Peninsula in the west to Anatolia in the east, extending as far north as central Germany, though it was absent from the Italian Peninsula. Early ''Prolagus'' species are thought to have inhabited subtropical swamp and wetland environments, with a similar ecology to the living marsh rabbit (''Sylvilagus palustris''). In many European Miocene localities remains of ''Prolagus'' are extraordinarily abundant, and ''Prolagus'' species probably played a key role as prey for many predators. During the late Miocene, ''Prolagus'' dispersed into North Africa due to the connection between Africa and Europe as a result of the Messinian salinity crisis. The range of ''Prolagus'' shifted southwards and substantially contracted outside of North Africa during the Pliocene leading to speciation. ''Prolagus'' first arrived in Corsica, Sardinia, and other Mediterranean islands at the early-late Pliocene boundary, likely due to an emergent land connection. The earliest remains of ''Prolagus'' on the islands are represented by the species ''P. figaro'', ancestral to '' P. sardus.'' Among the last continental species of ''Prolagus'' is ''P. calpensis'' from the Early-Middle Pleistocene of the Iberian Peninsula. By the beginning of the Late Pleistocene, ''Prolagus'' was confined to the single species ''P. sardus'' on Corsica, Sardinia and surrounding islands. While decline of the distribution ''Prolagus'' on the mainland of the continents was primarily driven by climatic change, the cause of the final extinction of the mainland ''Prolagus'' species is unclear, but one factor suggested is increased predation pressure. The Sardinian pika probably became extinct sometime between 800 BC (the timing of the last reliable radiocarbon date) and the 6th century AD, likely due to introductions of invasive species by humans.

Notes

References

Additional references of the Paleobiology Database

{{Taxonbar, from1=Q511863, from2=Q6005250

Prehistoric lagomorphs
Prehistoric placental genera
Miocene genus first appearances
Holocene extinctions
Fossil taxa described in 1853
Taxa named by Auguste Pomel