A NEW HUMERUS OF HOMUNCULUS PATAGONICUS, A STEM PLATYRRHINE FROM THE SANTA CRUZ FORMATION (LATE EARLY MIOCENE), SANTA CRUZ PROVINCE, ARGENTINA

Authors

  • John G. Fleagle Department of Anatomical Sciences, Renaissance School of Medicine, Stony Brook University, Stony Brook, NY.
  • Justin T. Gladman Shared Materials Instrumentation Facility (SMIF), Department of Engineering, Duke University, Durham, NC.
  • Richard F. Kay Department of Evolutionary Anthropology & Division of Earth and Climate Sciences, Nicholas School of the Environment, Duke University, Durham, NC.

DOI:

https://doi.org/10.5710/AMGH.29.09.2021.3447

Keywords:

Platyrrhini, Primate evolution, Postcrania, Locomotion

Abstract

We describe a well-preserved humerus of Homunculus patagonicus, a stem platyrrhine from the late early Miocene of the Santa Cruz Formation, Santa Cruz Province, Argentina. The distal part of a humerus was collected by Carlos Ameghino and figured in the 19th Century, but is now lost. Other described postcranial elements, also collected by him include a femur and a partial radius. Comparative observations are made with living and extinct platyrrhines, Oligocene African anthropoids, and extant strepsirrhines. Homunculus patagonicus was a robustly built arboreal quadruped that weighed between 2.2 and 2.6 kg. There is no evidence that the elbow could be fully extended as in living suspensory platyrrhines like Ateles. The medial orientation of the epicondyle suggests that the finger and wrist flexors were not aligned with the long axis of the limb, a distinction from more cursorial monkeys (extant cercopithecoids and the Cuban Pleistocene fossil platyrrhine Paralouatta have retroflexed medial epicondyles). Overall, the morphology is typically platyrrhine although the bone is quite robust. The robustness of the humerus is most comparable to that of early anthropoids from Africa rather than any extant platyrrhine.

Author Biographies

  • John G. Fleagle, Department of Anatomical Sciences, Renaissance School of Medicine, Stony Brook University, Stony Brook, NY.

    Department of Anatomical Sciences, Renaissance School of Medicine

  • Justin T. Gladman, Shared Materials Instrumentation Facility (SMIF), Department of Engineering, Duke University, Durham, NC.

    Shared Materials Instrumentation Facility (SMIF), Department of Engineering

Published

2022-01-06

Issue

Section

Articles

How to Cite

A NEW HUMERUS OF HOMUNCULUS PATAGONICUS, A STEM PLATYRRHINE FROM THE SANTA CRUZ FORMATION (LATE EARLY MIOCENE), SANTA CRUZ PROVINCE, ARGENTINA. (2022). Ameghiniana, 59(1), 78-96. https://doi.org/10.5710/AMGH.29.09.2021.3447