Asoriculus is an extinct genus of terrestrial shrews in the subfamily Soricinae (red-toothed shrews) and tribe Nectogalini, native to Europe (including the islands of Corsica, Sardinia and Sicily) and North Africa, from the Late Miocene (from around 6 million years ago) until the late Holocene (likely the late 1st millennium BC). The genus is closely related and possibly ancestral to the also recently-extinct Balearic shrews (Nesiotites), with their closest living relative being the Himalayan shrew (Soriculus nigrescens).
Taxonomy and evolution
The best known species of Asoriculus, Asoriculus gibberodon, was widespread in Europe from the Late Miocene (Messinian, MN13, from around 7.2-5.3 million years ago[1]) to the Early Pleistocene,[2] and was also present in Anatolia during the Pliocene.[3] The youngest records of the species date to the end of the Early Pleistocene approximately 846,000 ± 57,000 years ago in the Iberian Peninsula.[4] Another larger species, A. thenii, is sometimes also recognised in the Early Pleistocene of Europe.[4] The species Asoriculus maghrebiensis is known from the Pliocene-Pleistocene boundary (c. 2.5 million years ago) of Morocco in North Africa, making it the only known member of Soricinae to have been native to the African continent.[5]
Insular species are known from the Mediterranean islands of Sicily (A. burgioi Late Pliocene-Early Pleistocene), and Corsica-Sardinia including A. corsicanus (Late Pliocene-Early Pleistocene) and A. similis (Early Pleistocene-Late Pleistocene/Holocene).[6][7]Asoriculus is closely related and likely ancestral to the genus Nesiotites, known from the Balearic Islands from the Early Pliocene to the Holocene,[2] whose species have sometimes been included in Asoriculus.[8] The Asoriculus species A. corsicanus and A. similis were formerly included in Nesiotites in its original circumscription, though they are usually no longer treated as part of the genus.[2]
Based on DNA from Nesiotites, the closest living relative of Asoriculus is considered to be the terrestrial Himalayan shrew (Soriculus), belonging to a clade of terrestrial nectogaline shrews primarily known from Asia, also including the genera Episoriculus and Chodsigoa, rather than related to the nectogaline water shrews (Chimarrogale, Nectogale and Neomys). A molecular clock analysis suggests that Himalayan shrews and Balearic shrews genetically diverged approximately 6.44 million years ago.[2]
Phylogeny of Nectogalini based on DNA and morphological characters after Bover et al. (2018).[2]
The Sardinian-Coriscan species A. similis appears to have survived into the Holocene, when it became extinct sometime after human settlement of the islands, with remains apparently being found in Mesolithic and Neolithic aged archaeological sites in Sardinia. Studies in the 1990s suggested that Asoriculus became extinct on Corsica between 393 and 151 BC.[9]
Description
A. gibberodon has been estimated to weigh approximately 8.85 grams (0.312 oz). The insular species of Asoriculus are substantially larger than A. gibberodon and most other species of Nectogalini, with A. burgioi estimated to weigh 27.54 grams (0.971 oz) and A. similis 23.68 grams (0.835 oz), which has been cited as an example of island gigantism.[6]
^Storch, G., Qiu, Zh., and Zazhigin, V.S. 1998. Fossil history of shrews in Asia, p. 92-1. In Wójcik, J.M. and Wolsan, M. (eds.), Evolution of shrews. Mammal Research Institute Polish Academy of Sciences, Białowieża.
