Carnivoran hunting style and phylogeny reflected in bony labyrinth morphometry

Julia A Schwab,Cathrin Pfaff,Gerhard W Weber,Jürgen Kriwet

doi:10.1038/s41598-018-37106-4

Julia A Schwab, Cathrin Pfaff + Show 2 more

Open Access

https://doi.org/10.1038/s41598-018-37106-4

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Journal: Scientific Reports	Publication Date: Jan 11, 2019
Citations: 16	License type: open-access

Affiliation: University of Edinburgh, University of Vienna

Abstract

Carnivorans are a highly diverse and successful group of mammals, found on the top of the food chain. They originated in the Palaeocene (ca. 60 Ma) and have developed numerous lifestyles, locomotion modes and hunting strategies during their evolutionary history. Mechanosensory organs, such as the inner ear (which houses senses of equilibrium and hearing), represent informative anatomical systems to obtain insights into function, ecology and phylogeny of extant and extinct vertebrates. Using µCT scans, we examined bony labyrinths of a broad sample of various carnivoran species, to obtain new information about hunting behaviours of ancient carnivorans. Bony labyrinths were digitally reconstructed and measurements were taken directly from these 3D models. Principal component analyses generally separated various hunting strategies (pursuit, pounce, ambush and occasional), but also support their phylogenetic relationships (Canoidea vs. Feloidea). The height, width and length of all three semicircular canals show functional morphological adaptations, whereas the diameter of the canals, the height of the cochlea and particularly the angle between the lateral semicircular canal and the cochlea indicate a phylogenetic signal. The results demonstrate that the bony labyrinth provides a powerful ecological proxy reflecting both predatory habits as well as phylogenetic relationships in extinct and extant carnivorans.

Highlights

Carnivorans are a highly diverse and well-documented group of mammalian top predators
The third principal component (PC3) correlates positively with the width and length of the ASC; the height and length of the PSC; the width, radius and length of the LSC; the length of the crus commune (Cc); the height of the Co and all measured angles (ASC/PSC, ASC/LSC, LSC/PSC, LSC/Co), but correlates negatively with the height, diameter and radius of the ASC; the height, diameter and radius of the PSC; the height and diameter of the LSC and the width and length of the Co.A detailed list of the principal component analysis (PCA) scores is found in the electronic supplementary material (Supplementary Dataset 1)
In the Canonical Variate Analysis (CVA) the different hunting strategies observed in the investigated carnivorans separate well, as seen in the PCA

Summary

Introduction

Carnivorans are a highly diverse and well-documented group of mammalian top predators They comprise two monophyletic clades, the Canoidea (dog–like carnivorans) and Feloidea (cat–like carnivorans)[1] that can be distinguished based on morphological (e.g.2), and molecular data (e.g.3). The timing of the split between the two major clades has not been fully resolved[4,5] These animals originated in the Palaeocene and distinctly diversified in the last 60 Million years[1,6,7]. There has been an increase in studies using the inner ear, the sensory organ responsible for equilibrium and hearing as a proxy for inferring ecological niche (Fig. 1). We use the most diversified sample of carnivoran bony labyrinths yet assembled to predict hunting behaviours in extinct taxa, providing novel insights into the evolution, lifestyle and especially hunting strategies of carnivoran mammals

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