井陉三趾马动物群是在太行山东麓的首次确切发现, 本文描述了其中的马科和犀科化石。马科标本可鉴定为平齿西瓦三趾马Sivalhippus platyodus和原始长鼻三趾马Proboscidipparion pater, 前者上颊齿褶皱复杂, 原尖唇侧圆隆, 舌侧平, 下颊齿双叶次角形, 下马刺单一或双分, 下内尖强烈收缩, 后谷狭长; 后者下乳齿双叶贺风型, 下马刺微弱或不发育, 下内尖和后谷的长轴方向与牙齿长轴方向平行。犀科化石可鉴定为林氏山西犀 Shansirhinus ringstroemi和真犀亚科属种未定Rhinocerotinae gen. et sp. indet., 前者下颌联合部中度侧向扩展, 下门齿呈獠牙状, 下三角座呈角状U形, 下后尖前壁可见收缩, 下内脊向后倾斜; 后者上前臼齿的原尖和次尖不收缩, 反前刺不发育, 肢骨较粗壮。根据这些化石的生活习性和时代分布特点, 推测该动物群生存于开放的森林草原环境, 时代为晚中新世保德期晚期至早上新世高庄期早期, 更可能是高庄期最早期。

This paper reports the first confirmed site of the Jingxing Hipparion fauna from the eastern piedmont of the Taihang Mountains and describes Equidae and Rhinocerotidae fossils from this fauna. The Equidae specimens are identified as Sivalhippus platyodus, characterized by with labially rounded and lingually flattened protocones and complex folds on upper cheek tooth, angular double-knots, single or bifid pli caballinids, strongly constricted entoconids, and narrow, elongated postflexids on lower cheek tooth; and Proboscidipparion pater, distinguished by a houfenoid double-knot, weak or absent pli caballinid, and the long axes of entoconid and postflexid parallel to that of the lower deciduous tooth. The Rhinocerotidae fossils include Shansirhinus ringstroemi with a moderately expanded mandibular symphysis, tusk-like lower incisors, angular U-shaped trigonid, a strongly constricted anterior wall of the metaconid, and a posteriorly tilted entolophid; and Rhinocerotinae gen. et sp. indet., characterized by poorly developed protocone and hypocone constrictions, antecrochets on premolars, and relatively robust limb bones. Based on the ecological habits and chronological distribution of these species, it is inferred that this fauna inhabited in an open forest-grassland environment. Biochronological analysis suggests an age ranging from the late Baodean of the Late Miocene to the early Gaozhuangian of the Early Pliocene, most likely corresponding to the earliest Gaozhuangian.

国家自然科学基金重点项目(42430207)、国家重点研发计划(2023YFF0804501)、河北省自然科学基金(D2024403014)和河北地质大学博士科研启动基金(BQ2024018)联合资助