Morphological Stasis in Wing Traits Despite Species Diversification in African and Malagasy Miniopterus Bats

Islands often give rise to adaptive radiations, owing to the absence of mainland competitors and predators. The long-fingered bats (Miniopterusspp.) provide an opportunity to examine this pattern, as the genus includes sister radiations on Madagascar and on the African mainland. We measured wing elements related to flight in these two Miniopterus sister clades: one with 12 species from Madagascar and the other with nine species from Kenya, representing a comparable area of continental Africa. Principal component analysis revealed that Miniopterus species cluster within a narrow region of morphospace, with PC1 representing a size gradient that explains 93.6% of the variance in seven wing measurements. A phylomorphospace analysis integrating a resolved species phylogeny demonstrated that closely related species often occupy similar regions of morphospace, particularly among the smaller Malagasy taxa. Euclidean distance matrices showed similar nearest, average, and farthest neighbor values between Kenya and Madagascar, indicating strong morphological resemblance. Multivariate dispersion analysis yielded an observed mean dispersion of 1.8137, which did not significantly differ from a randomized expectation (p = 0.08819), suggesting that species are not more regularly or unevenly distributed than expected by chance. These findings indicate limited shape divergence in wing morphology between these two Miniopterus radiations. This work highlights the complexity of detecting adaptive patterns and suggests the need to incorporate broader ecological and behavioral data when studying diversification in bats.