Sinomegaceros

Sinomegaceros yabei head closeup

The first species of the genus S. ordosianus and S. pachyosteus were named by pioneering Chinese paleontologist C. C. Young as species of Cervus in 1932 for material from Zhoukoudian.[2] In a review of the paper the subsequent year Dietrich created the name Sinomegaceros as a subgenus of Cervus to house the species, with S. pachyosteus as the type species.[3] Due to the fact that the name was not published in a formal research paper, it was not widely used for several decades after publication.[4] The species S. yabei was named in 1938.[5] In the following decades various researchers considered it a subgenus of Megaloceros,[6][7] or a distinct genus.[8][9] Several named species are likely to be junior synonyms.[4] The best known species are Sinomegaceros yabei from the Middle to Late Pleistocene of Japan, alongside Sinomegaceros pachyosteus from the late Early Pleistocene to Late Pleistocene of China.

The antlers have palmate brow tines, with the palmation generally orientated transversely and vertically.[4][10] The mandibles of Sinomegaceros, like those of Megaloceros giganteus, are robust, with the robustness being the most extreme in S. pachyosteus.[4][11]

S. yabei and S. pachyosteus are suggested to have been grazers.[4][11]

One of the oldest species in the genus is Sinomegaceros tadzhikistanis, known from the Late Pliocene-Early Pleistocene of Tajikistan.[12] The oldest species of the genus in China is Sinomegaceros konwanlinensis, from Gongwaling in Northern China, dating to the Early Pleistocene, around 1.6 million years ago.[10][4] S. fabellatus is known from fossils spanning the latest Early Pleistocene to early Middle Pleistocene. S. sangwonensis is known from fossils spanning the mid-Middle Pleistocene. The oldest fossils of S. pachyosteus date to around 700,000 years ago, during the early Middle Pleistocene while the youngest fossils of the species date to the late Middle Pleistocene. The species S. yabei and S. ordosianus first appeared during the late Middle Pleistocene.[10] It has been suggested that both S. pachyosteus and S. yabei ultimately derive from S. konwanlinensis.[4] The youngest known dates of S. ordosianus are around 35-50,000 years ago.[13] While often stated to have become extinct around 12,000 years ago, a lack of high-quality radiocarbon dates makes the time of extinction uncertain for S. yabei, with the only certain radiocarbon dates dating to around 40,000 years ago.[14]

Remains of S. yabei at Lake Nojiri in Nagano Prefecture of Honshu, Japan, dating to approximately 37,900 to 42,600 years Before Present have been found associated with spear-shaped wood pieces and large pebbles, with the long bones fractured, with their fragments bearing percussive marks, suggesting that the deer were butchered by humans at the site, with the long bones likely cracked to extract bone marrow.[15] S. ordosianus is suggested to have likely been hunted by archaic humans, based on the finds of its remains in archaeological sites.[10]