Arno river dog
Canis arnensis (or Arno River dog) is an extinct species of canine that was endemic to Mediterranean Europe during the Early Pleistocene. The Arno River dog has been described as a small jackal-like dog. Its anatomy and morphology relate it more to the modern golden jackal (Canis aureus ) than to the larger Etruscan wolf of that time. It is probably the ancestor of modern jackals.
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C. arnensis was a medium-sized canid, with a close affinity to modern canids. It had a slightly smaller cranial length than both C. etruscus and the extant C. lupus. C. arnensis featured a lower and more pronounced forehead, with less-developed sagittal and nuchal crests and a bulkier braincase than C. etruscus ; in addition, the nasal bones were found to be shorter, stopping short of the maxillofrontal suture.Show More
C. arnensis and C. etruscus have been compared, as they are morphologically similar and are believed to have spread to Western Europe together during the so-called "Canis Event". Morphometric analysis of the cranium and upper teeth show that both C. arnensis and C. etruscus showed characteristics of an intermediate between extant wolves and jackals, with C. arnensis being slightly more jackal-like and C. etruscus slightly more wolf-like; however, in some cranial characteristics, C. arnensis is more wolf-like.Show Less
The first identification of C. arnensis followed the discovery of a fossil in the Upper Valdarno. Fossils of the species have only been found in the period of time known as the Tasso Faunal Unit of Italy. The species was endemic to Mediterranean Europe and lived during the Early Pleistocene era. It is believed that C. arnensis spread across Europe as the result of a dispersal event which populated the continent with the first modern canids. The species arrived in Italy around 1.9 Ma and was homogenized across southern Europe during the late Villafranchian.