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Brain volume of the newly‐discovered species Rhynchocyon udzugwensis (Mammalia: Afrotheria: Macroscelidea): implications for brain‐body allometry within Afrotheria
Author(s) -
Kaufman Jason A.,
Turner Gregory H.,
Holroyd Patricia A.,
Rovero Francesco,
Grossman Ari
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.725.1
Subject(s) - allometry , brain size , proboscidea , insectivora , biology , zoology , ecology , magnetic resonance imaging , medicine , radiology
The Gray‐faced Sengi ( Rhynchocyon udzugwensis ) is a newly‐discovered species of Sengi (Elephant‐Shrew) and is the largest known extant representative of the order Macroscelidea. The discovery of R. udzugwensis provides an opportunity to investigate the allometric scaling relationship between brain size and body size within the superorder Afrotheria. We performed a 3D spin echo magnetic resonance imaging (MRI) scan on a preserved adult specimen of R. udzugwensis using a 7‐Tesla high‐field MR imaging system. The brain was manually segmented and its volume was compiled into a dataset containing previously‐published allometric data on 29 other species of insectivore‐grade mammals including representatives of Afrotheria, Soricomorpha and Erinaceomorpha. Results of log‐linear regression confirm a strong correlation between brain size and body size among all taxa. Post‐hoc tests indicate a grade‐shift between Macroscelidea and other members of Afrotheria, Soricomorpha and Erinaceomorpha: the Macroscelidea have larger positive brain‐size residuals. As a group, the Macroscelidea have larger brains for a given body size than that observed for the other insectivores. Further research incorporating Hyracoidea, Proboscidea, and Sirenia are necessary for a more‐complete understanding of brain allometry in Afrotheria compared to other Eutherian mammals. This research was supported by an intramural grant from Midwestern University.