The shoulder musculature of Rhynchocyon cirnei

Traditionally sengis (elephant shrews, order Macroscelidea) have been studied in light of other insect‐eating mammals without a firm understanding of their phylogeny, and all prior work on their myology has been made to animals of similar size rather than similar ancestry. Sengis are now recognized as part of the Afrotheria. Afrotheres have a long evolutionary history and currently few morphological characters are known to unite them, in part due to a limited knowledge of their soft tissue anatomy within a phylogenetically‐meaningful context. One poorly studied afrothere is the giant sengi, Rhynchocyon . We conducted a dissection of the shoulder and arm musculature of R. cirnei . A single specimen preserved in ethanol was dissected using standard dissection techniques under a Zeiss microscope. Muscles were cleaned to determine origin(s), insertion(s) and extent. Each muscle was only reflected after it was documented and photographed. We also identified innervations of each muscle whenever possible. We confirmed prior observations on sengi myology and provide new data on innervations. Comparisons highlight the distinctiveness of sengis relative to other afrotheres where known but also highlight the need for considerable additional anatomical work to firmly establish which features are apomorphies and which may represent shared derived characters among afrotheres. This work is supported by a Midwestern University intramural grant