Repeated evolution of carnivory among Indo-Australian rodents

Abstract

Convergent evolution, often observed in island archipelagos, provides compelling evidence for the importance of natural selection as a generator of species and ecological diversity. The Indo-Australian Archipelago (IAA) is the world's largest island system and encompasses distinct biogeographic units, including the Asian (Sunda) and Australian (Sahul) continental shelves, which together bracket the oceanic archipelagos of the Philippines and Wallacea. Each of these biogeographic units houses numerous endemic rodents in the family Muridae. Carnivorous murids, that is those that feed on animals, have evolved independently in Sunda, Sulawesi (part of Wallacea), the Philippines, and Sahul, but the number of origins of carnivory among IAA murids is unknown. We conducted a comprehensive phylogenetic analysis of carnivorous murids of the IAA, combined with estimates of ancestral states for broad diet categories (herbivore, omnivore, and carnivore) and geographic ranges. These analyses demonstrate that carnivory evolved independently four times after overwater colonization, including in situ origins on the Philippines, Sulawesi, and Sahul. In each biogeographic unit the origin of carnivory was followed by evolution of more specialized carnivorous ecomorphs such as vermivores, insectivores, and amphibious rats.

Tempo and mode of mandibular shape and size evolution reveal mixed support for incumbency effects in two clades of island‐endemic rodents (Muridae: Murinae)*

“…() and Rowe et al. () came to similar conclusions as we did: the classical model of early‐burst evolution used to support a hypothesis of adaptive radiation is not the likely mechanism of morphological evolution in muroids broadly, murines specifically, nor even LOE rodents locally. Instead, a constant background process with some major shifts to new adaptive zones appears to provide a better explanation of the observed morphological variation, with similar selective pressures in convergently evolved carnivorous rodents (Table , Fig.…”

“…From a different perspective, Rowe et al. () documented the remarkable convergence among independently evolving carnivorous rodents that exhibit shrewlike morphology (such as Soricomys and Archboldomys on Luzon, and Melasmothrix on Sulawesi) as well as the bizarre “tweezer‐snouted” morphology exhibited by Rhynchomys on Luzon and Paucidentomys on Sulawesi (Rowe et al. ).…”

The ecology of a continental evolutionary radiation: Is the radiation of sigmodontine rodents adaptive?

“…Elongation of the rostrum is common among mammals and may arise in response to selective processes (e.g., Freeman ; Christiansen and Wroe 2007; Monteiro and Nogueira ; Rowe et al. ). Similar patterns of rostral elongation in insectivores have also been observed in other rodent families (Samuels ).…”

Two new species of Trichuris (Nematoda: Trichuridae) collected from endemic murines of Indonesia

“…The morphological resemblance in the spicule morphology between the present two new species suggests their close phylogenetic relationship. Although Echiothrix and Mallomys are old-endemic murine genera of the area, they belong to different tribes, Rattini and Hydromini, and were considered to have diverged in the Tortonian era of the Miocene about 12.5 million years ago (Fabre et al, 2013;Rowe et al, 2016). It remains to be elucidated whether the morphological resemblance between the two new species of Trichuris described herein is only homoplasy or actually reflects a close phylogenetic relationship of the parasites.…”