Data from: New pantolestids (Mammalia; Eutheria) from the late Paleocene (late middle Tiffanian) Roche Percée local fauna, southeastern Saskatchewan, Canada

The Pantolestidae are an extinct family of mammals known principally from
the early Paleocene to late Oligocene (from approximately 64 to 30 million
years ago) of North America and Europe. Although never particularly
abundant, pantolestids are relatively well represented in the Eocene and
Oligocene, with several taxa known from exceptionally well-preserved
skulls and postcranial material. The early evolutionary history of the
group, however, similar to that of many contemporaneous mammals, remains
comparatively poorly known. The current study reports on several
previously undescribed pantolestids from the early late Paleocene (late
middle Tiffanian, Ti4) Roche Percée local fauna, Ravenscrag Formation, of
southeastern Saskatchewan, Canada. Aatotomus placochton n. gen. n. sp.
resembles the enigmatic pantolestid Paleotomus in having sectorial
premolars with well-developed crests and tall, sharp molar trigonids, but
differs principally in possessing narrow molar talonids. Besseocetor
krausei n. sp. shares numerous similarities with B. thomsoni and B.
septentrionalis but differs in being considerably smaller and less robust.
Palaeosinopa reclusum n. sp., the oldest species of Palaeosinopa yet
discovered, reveals a unique combination of primitive and derived
pantolestid features, and supports previous suggestions of a close
evolutionary relationship between Palaeosinopa and Bessoecetor. The new
taxa document an unusually high diversity of pantolestids in the Tiffanian
of western Canada and provide important new knowledge to the evolutionary
history of this group during the Paleocene.

潘诺莱斯特兽科（Pantolestidae）是一类已灭绝的哺乳类科，其化石主要发现于北美与欧洲的古新世早期至渐新世晚期（约6400万至3000万年前）。尽管该类群的丰度始终未达较高水平，但在始新世与渐新世地层中其化石记录相对丰富，已有多个类群基于保存异常完好的头骨及颅后骨骼材料被报道。然而，与诸多同期哺乳类类似，该类群的早期演化历史目前仍相对鲜为人知。本研究报道了采自加拿大萨斯喀彻温省东南部雷文斯克拉格组罗什佩尔塞本地动物群的晚古新世早期（蒂芙尼阶中晚期，Ti4）的多个此前未被描述的潘诺莱斯特兽科类群。阿阿托托慕斯兽 新属新种（Aatotomus placochton n. gen. n. sp.）与形态神秘的古汤姆森兽属（Paleotomus）类群相似，均具有发育有良好脊状结构的剪型前臼齿以及高锐的臼齿下三角座，但二者的核心区别在于新类群拥有狭窄的臼齿下跟座。克劳斯贝塞克托兽 新种（Besseocetor krausei n. sp.）与汤姆森贝塞克托兽（B. thomsoni）及北方贝塞克托兽（B. septentrionalis）存在诸多相似特征，但体型显著更小且结构更为纤细。隐居帕辛诺帕兽 新种（Palaeosinopa reclusum n. sp.）是目前已发现的最古老的帕辛诺帕兽属（Palaeosinopa）物种，其展现出原始与衍生潘诺莱斯特兽科特征的独特组合，支持了此前关于帕辛诺帕兽属与贝塞克托兽属（Bessoecetor）存在密切演化亲缘关系的推测。上述新类群记录了加拿大西部蒂芙尼阶时期潘诺莱斯特兽科异常高的物种多样性，为该类群在古新世时期的演化历史提供了关键的新认知。