Defensive Morphology

Intraspecific competition: A missing link in dermal armour evolution?

“…The anti‐predatory advantages are often dubious (Broeckhoven et al, 2015) and the costs of bearing armour high: a negative effect of armour on locomotor performance has been observed in sticklebacks (Andraso, 1997; Andraso & Barron, 1995; Bergstrom, 2002) and girdled lizards (Losos et al, 2002), whereas armoured mammals, such as armadillos, suffer a correlated reduction in encephalization (Stankowich & Romero, 2017). For this reason, there has been a recent shift towards considering alternative explanations for the (multi)functionality of dermal armour (Broeckhoven, 2019). To help facilitate the adoption of this paradigm shift, I put forward the concept of ‘fighting advantage’, the view that aggressive interactions with conspecifics might be a key selective pressure favouring, not only the evolution of weaponry (e.g.…”

“…Animals have independently evolved a suite of morphological adaptations that play an important role in preventing physical damage to vital anatomical structures (Broeckhoven, 2019). While these protective strategies may take many forms, one of the phylogenetically most widespread types comprises the mineralized integumentary structures or ‘dermal armour’ of vertebrates (reviewed in Hendrickx et al, 2022; Sire et al, 2009; Vickaryous & Sire, 2009; Figure 1).…”

“…The anti-predatory advantages are often dubious and the costs of bearing armour high: a negative effect of armour on locomotor performance has been observed in sticklebacks (Andraso, 1997;Andraso & Barron, 1995;Bergstrom, 2002) and girdled lizards (Losos et al, 2002), whereas armoured mammals, such as armadillos, suffer a correlated reduction in encephalization (Stankowich & Romero, 2017). For this reason, there has been a recent shift towards considering alternative explanations for the (multi)functionality of dermal armour (Broeckhoven, 2019).…”