Evolutionary implications of dental anomalies in bats

Abstract

The gain or loss of anatomical features is an important mechanism of morphological evolution and ecological adaptation. Dental anomalies—the loss or gain of teeth—are widespread and a potential source of craniodental specialization among mammals, yet their macroevolutionary patterns have been rarely explored. We present the first phylogenetic comparative study of dental anomalies across the second largest mammal Order, Chiroptera (bats). We conducted an extensive literature review and surveyed a large sample of museum specimens to analyze the types and prevalence of dental anomalies across bats, and performed phylogenetic comparative analyses to investigate the role of phylogenetic history and dietary specialization on incidence of dental anomalies. We found dental anomalies have a significant phylogenetic signal, suggesting they are not simply the result of idiosyncratic mutations or random developmental disorders, but may have ancestral genetic origins or result from shared developmental pathways among closely related species. The incidence of dental anomalies was not associated with diet categories, suggesting no effect of craniodental specialization on dental anomalies across bats. Our results give insight into the macroevolutionary patterns of dental anomalies in bats, and provide a foundation for investigating new hypotheses underlying the evolution of dental variation and diversity in mammals.

Phenotypic traits evolution and morphological traits associated with echolocation calls in cryptic horseshoe bats (Rhinolophidae)

“…This emphasizes the importance of understanding trait evolution in bats and optimizing the selection of traits that have often been neglected despite their importance. The majority of the previous evolutionary trait studies on bats focus on skulls and dentition (Jacobs et al, 2014; Clavel & Morlon, 2020; Esquivel et al, 2021; Giacomini et al, 2021), but few studies have been focussed on measuring the noseleaf traits, particularly in Old‐World bats.…”

“…Research into the evolution of phenotypic traits in bats is clearly in the preliminary stages. Nevertheless, previous studies have shown interesting findings on the evolutionary relationship among morphological traits, echolocation, ecological demands, functional traits, and bat behavior (i.e., Jacobs et al, 2014; Brokaw & Smotherman, 2020; López‐Cuamatzi et al, 2020; Esquivel et al, 2021). Yet, gathering complex data for greater systematic sampling to achieve robust results on these inter‐relationships remains a challenge.…”

Bilateral agenesis of M3 in the little yellow-shouldered bat, Sturnira lilium (Chiroptera: Phyllostomidae)

“…as environmental instability (Chemisquy & Martin 2016), limited gene flow (Martin 2013), atavisms (Hall 2010), or even aleatory mutations (Hauer 2002). At least for bats, the phylogenetic structure in the occurrence of dental anomalies indicates that some shared processes among related species are also influencing the phenomenon (Esquivel et al 2021). The main types of dental anomalies described for the order Chiroptera are hypodontia (the absence of teeth), and polyodontia (the presence of supernumerary teeth) (Esquivel et al 2021).…”

“…At least for bats, the phylogenetic structure in the occurrence of dental anomalies indicates that some shared processes among related species are also influencing the phenomenon (Esquivel et al 2021). The main types of dental anomalies described for the order Chiroptera are hypodontia (the absence of teeth), and polyodontia (the presence of supernumerary teeth) (Esquivel et al 2021). The etiologies of these abnormal morphologies, however, are not fully comprehended.…”

“…Authors should be encouraged to report morphological anomalies, as this trend hinders the dissemination of peer-reviewed materials on phenomena such as dental anomalies. These anomalies often go unnoticed and remain poorly understood (Esquivel et al 2021), limiting our capacity to comprehend these occurrences and further our understanding.…”