Distribution of bone modification traces attributed to tungid fleas on a large late Pleistocene specimen of Glyptodon clavipes, Mar del Plata, Argentina

The dermal armour that characterizes several vertebrate lineages, such as turtles, lizards, crocodilians and cingulate xenarthrans forms a substrate that can potentially record the interaction between parasites and their hosts in the fossil record. Bone modification traces attributed to tungid fleas have been observed on the osteoderms of several large extinct armadillos. These often occur on disarticulated osteoderms rendering it difficult to identify the distribution of the parasite on the animal. This contribution assesses then distribution of the trace fossil Karethraichnus kulindros on an articulated carapace of the giant chlampyphorid cingulate xenarthran Glyptodon clavipes. Karethraichnus kulindros are not evenly distributed on the carapace analysed. No traces were observed on the upper part of the carapace. Traces in the posterior, pelvic and thoracic regions were sparsely distributed (<0.1/100 cm2). One small patch with ∼ 5 traces/100 cm2 occurred on the lower left pectoral portion of the carapace. The densest accumulation of traces (5–9 traces/100 cm2) occurred in an irregular patch in the anterior region, immediately behind the skull. The parasites, herein interpreted to be tungid fleas related to Tunga perforans, had a clear site preference for parts of the carapace protected from easy access during self-grooming and avoided the widest part of the carapace which would have likely brushed up against vegetation and branches in dense brush.