Abstract

The osseous elements of the foot and ankle are described in detail, illustrated, and measured for the Hispaniolan solenodon, Solenodon paradoxus Brandt, 1833, one of two extant species of the lipotyphlan family Solenodontidae. Comparisons are made with the same elements in representatives of the three remaining extant families of lipotyphlans, the soricid Crocidura luna, the talpid Parascalops breweri, and the erinaceid Erinaceus europaeus. The solenodon foot is generalized but with a unique modification regarding the entocuneiform; it has an elongate medial spur with a sizeable facet for the astragalar head. The other lipotyphlans studied have a medial spur of the entocuneiform, but it is well separated from the astragalus by the navicular. Crocidura luna also has a remarkable modification; the ectal facets on the astragalus and calcaneus have opposing concavoconvex surfaces.
Prior authors have used indices of various fore- and hind limb elements to evaluate substrate use during locomotion. Phalangeal indices (length of the manual or pedal digits to the length of the metapodial for a particular ray) in didelphid marsupials and primates have been found to match observations of reliance on fine supports versus the ground or large-diameter supports; longer digits to metapodials are found in graspers. We combine pedal phalangeal indices from the four studied lipotyphlans with those published for didelphid marsupials and primates in a Principal Components Analysis. The results separate the primates from the other taxa and all taxa along a fine support/terrestrial gradient. The lipotyphlans are at the terrestrial end with the one carnivoran in the sample, the raccoon Procyon lotor.

Key Words: astragalus; calcaneus; Crocidura luna; Erinaceus europaeus; lipotyphlan; Parascalops breweri; phalangeal index; Solenodon paradoxus; tarsals.