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Rowsey DM, Duya MRM, Ibañez JC, Jansa SA, Rickart EA, Heaney LR. A new genus and species of shrew-like mouse (Rodentia: Muridae) from a new center of endemism in eastern Mindanao, Philippines. J Mammal 2022; 103:1259-1277. [PMID: 36660555 PMCID: PMC9841421 DOI: 10.1093/jmammal/gyac057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 05/13/2022] [Indexed: 01/17/2023] Open
Abstract
The Philippine archipelago hosts an exceptional diversity of murid rodents that have diversified following several independent colonization events. Here, we report the discovery of a new species of rodent from Mt. Kampalili on eastern Mindanao Island. Molecular and craniodental analyses reveal this species as a member of a Philippine "New Endemic" clade consisting of Tarsomys, Limnomys, and Rattus everetti (tribe Rattini). This new species of "shrew-mouse" is easily distinguished from its relatives in both craniodental and external characteristics including a long, narrow snout; small eyes and ears; short, dark, dense fur dorsally and ventrally; stout body with a tapering, visibly haired tail shorter than head and body length; stout forepaws; bulbous and nearly smooth braincase; narrow, tapering rostrum; short incisive foramina; slender mandible; and narrow, slightly opisthodont incisors. This new genus and species of murid rodent illustrates that murids of the tribe Rattini have exhibited greater species and morphological diversification within the Philippines than previously known and provides evidence that Mt. Kampalili represents a previously unrecognized center of mammalian endemism on Mindanao Island that is deserving of conservation action.
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Affiliation(s)
| | - Mariano Roy M Duya
- Institute of Biology, University of the Philippines–Diliman, Quezon City, Philippines
| | - Jayson C Ibañez
- Philippine Eagle Foundation, Philippine Eagle Center, Malagos, Baguio District Davao City, Philippines
| | - Sharon A Jansa
- Department of Ecology, Evolution, and Behavior, University of Minnesota, St. Paul, Minnesota, USA
| | - Eric A Rickart
- Natural History Museum of Utah, University of Utah, Salt Lake City, Utah, USA
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Petrosky AL, Rowsey DM, Heaney LR. Molecular assessment of dietary niche partitioning in an endemic island radiation of tropical mammals. Mol Ecol 2021; 30:5858-5873. [PMID: 34460971 DOI: 10.1111/mec.16158] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Revised: 07/27/2021] [Accepted: 08/11/2021] [Indexed: 01/02/2023]
Abstract
Island radiations represent unique evolutionary histories in unique ecological contexts. These radiations provide opportunities to investigate ecological diversification in groups that typically exhibit niche partitioning among their constituents, including partitioning of food resources. DNA metabarcoding produces finer levels of diet identification than traditional methods, allowing us to examine dietary niche partitioning in communities or clades in which species share superficially similar diets. Here, we use DNA metabarcoding to investigate dietary niche partitioning in an endemic radiation of mammals in the Philippines. Our data reveal niche partitioning as well as phylogenetically-uncorrelated adaptive evolution in this small mammal community. Because 70% of the focal species belong to the tribe Chrotomyini, an endemic Philippine radiation of murid rodents that feed extensively on earthworms, this study sheds light on dietary adaptation and its role in the co-occurrence of closely related species. Our results reveal fine-scale resource partitioning within this community; our data provide compelling evidence for niche partitioning of diet that was masked by previous diet categories and will help in further dissecting the model adaptive radiation of endemic small mammals on Luzon. This study reinforces the notion that DNA metabarcoding can be a valuable tool for investigating both ecological relationships and evolutionary ecology at the community and phylogenetic level, respectively.
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Affiliation(s)
- Anna L Petrosky
- Field Museum of Natural History, Chicago, Illinois, USA.,Committee on Evolutionary Biology, University of Chicago, Chicago, Illinois, USA
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Ochoa J, Mijares ASB, Piper PJ, Reyes MC, Heaney LR. Three new extinct species from the endemic Philippine cloud rat radiation (Rodentia, Muridae, Phloeomyini). J Mammal 2021. [DOI: 10.1093/jmammal/gyab023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Abstract
The 18 extant members of the Tribe Phloeomyini, the “cloud rats,” constitute an endemic Philippine radiation of arboreal herbivores that range in size from ca. 18 g to 2.7 kg, most occurring in cloud forest above 1,200 m elevation. Although calibrated phylogenies indicate that the Phloeomyini is estimated to have begun diversifying within the Philippines by ca. 10–11 million years ago, no extinct fossil species have been described, severely limiting our understanding of this distinctive radiation. Our studies of fossil and subfossil small mammal assemblages from the lowland Callao Caves complex in NE Luzon, Philippines, have produced specimens of Phloeomyini that date from ca. 67,000 BP to the Late Holocene (ca. 4,000 to 2,000 BP). We identify three extinct species that we name as new members assigned to the genera Batomys, Carpomys, and Crateromys, distinguished from congeners by body size, distinctive dental and other morphological features, and occupancy of a habitat (lowland forest over limestone) that differs from the high-elevation mossy forest over volcanic soils occupied by their congeners. Batomys cagayanensis n. sp. is known only from two specimens from ca. 67,000 BP; Carpomys dakal n. sp. and Crateromys ballik n. sp. were present from ca. 67,000 BP to the Late Holocene. These add to the species richness and morphological diversity of this endemic Philippine radiation of large folivores, and show specifically that the lowland fauna of small mammals on Luzon was more diverse in the recent past than it is currently, and that Luzon recently supported five species of giant rodents (ca. 1 kg or more). All three occurred contemporaneously with Homo luzonensis, and two, the new Carpomys and Crateromys, persisted until the Late Holocene when multiple exotic mammal species, both domestic and invasive, were introduced to Luzon, and new cultural practices (such as making pottery) became evident, suggesting that modern humans played a role in their extinction.
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Affiliation(s)
- Janine Ochoa
- Department of Anthropology, University of the Philippines, Diliman, Quezon CityPhilippines
| | - Armand S B Mijares
- Archaeological Studies Program, University of the Philippines, Diliman, Quezon City, Philippines
- National Museum of the Philippines, Manila, Philippines
| | - Philip J Piper
- Archaeological Studies Program, University of the Philippines, Diliman, Quezon City, Philippines
- National Museum of the Philippines, Manila, Philippines
| | | | - Lawrence R Heaney
- National Museum of the Philippines, Manila, Philippines
- Field Museum of Natural History, 1400 S Lake Shore Drive, Chicago, IL, USA
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Roycroft E, Achmadi A, Callahan CM, Esselstyn JA, Good JM, Moussalli A, Rowe KC. Molecular Evolution of Ecological Specialisation: Genomic Insights from the Diversification of Murine Rodents. Genome Biol Evol 2021; 13:6275684. [PMID: 33988699 PMCID: PMC8258016 DOI: 10.1093/gbe/evab103] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/07/2021] [Indexed: 12/15/2022] Open
Abstract
Adaptive radiations are characterized by the diversification and ecological differentiation of species, and replicated cases of this process provide natural experiments for understanding the repeatability and pace of molecular evolution. During adaptive radiation, genes related to ecological specialization may be subject to recurrent positive directional selection. However, it is not clear to what extent patterns of lineage-specific ecological specialization (including phenotypic convergence) are correlated with shared signatures of molecular evolution. To test this, we sequenced whole exomes from a phylogenetically dispersed sample of 38 murine rodent species, a group characterized by multiple, nested adaptive radiations comprising extensive ecological and phenotypic diversity. We found that genes associated with immunity, reproduction, diet, digestion, and taste have been subject to pervasive positive selection during the diversification of murine rodents. We also found a significant correlation between genome-wide positive selection and dietary specialization, with a higher proportion of positively selected codon sites in derived dietary forms (i.e., carnivores and herbivores) than in ancestral forms (i.e., omnivores). Despite striking convergent evolution of skull morphology and dentition in two distantly related worm-eating specialists, we did not detect more genes with shared signatures of positive or relaxed selection than in a nonconvergent species comparison. Although a small number of the genes we detected can be incidentally linked to craniofacial morphology or diet, protein-coding regions are unlikely to be the primary genetic basis of this complex convergent phenotype. Our results suggest a link between positive selection and derived ecological phenotypes, and highlight specific genes and general functional categories that may have played an integral role in the extensive and rapid diversification of murine rodents.
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Affiliation(s)
- Emily Roycroft
- School of BioSciences, The University of Melbourne, Parkville, Victoria, Australia.,Sciences Department, Museums Victoria, Melbourne, Victoria, Australia.,Division of Ecology and Evolution, Research School of Biology, The Australian National University, Acton, Australian Capital Territory, Australia
| | - Anang Achmadi
- Museum Zoologicum Bogoriense, Research Center for Biology, Cibinong, Jawa Barat, Indonesia
| | - Colin M Callahan
- Division of Biological Sciences, University of Montana, Missoula, Montana, USA
| | - Jacob A Esselstyn
- Museum of Natural Science, Louisiana State University, Baton Rouge, Louisiana, USA.,Department of Biological Sciences, Louisiana State University, Baton Rouge, Los Angeles, USA
| | - Jeffrey M Good
- Division of Biological Sciences, University of Montana, Missoula, Montana, USA.,Wildlife Biology Program, University of Montana, Missoula, Montana, USA
| | - Adnan Moussalli
- School of BioSciences, The University of Melbourne, Parkville, Victoria, Australia.,Sciences Department, Museums Victoria, Melbourne, Victoria, Australia
| | - Kevin C Rowe
- School of BioSciences, The University of Melbourne, Parkville, Victoria, Australia.,Sciences Department, Museums Victoria, Melbourne, Victoria, Australia
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Marcy AE, Guillerme T, Sherratt E, Rowe KC, Phillips MJ, Weisbecker V. Australian Rodents Reveal Conserved Cranial Evolutionary Allometry across 10 Million Years of Murid Evolution. Am Nat 2020; 196:755-768. [PMID: 33211559 DOI: 10.1086/711398] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AbstractAmong vertebrates, placental mammals are particularly variable in the covariance between cranial shape and body size (allometry), with rodents being a major exception. Australian murid rodents allow an assessment of the cause of this anomaly because they radiated on an ecologically diverse continent notably lacking other terrestrial placentals. Here, we use 3D geometric morphometrics to quantify species-level and evolutionary allometries in 38 species (317 crania) from all Australian murid genera. We ask whether ecological opportunity resulted in greater allometric diversity compared with other rodents or whether conserved allometry suggests intrinsic constraints and/or stabilizing selection. We also assess whether cranial shape variation follows the proposed rule of craniofacial evolutionary allometry (CREA), whereby larger species have relatively longer snouts and smaller braincases. To ensure we could differentiate parallel versus nonparallel species-level allometric slopes, we compared the slopes of rarefied samples across all clades. We found exceedingly conserved allometry and CREA-like patterns across the 10-million-year split between Mus and Australian murids. This could support both intrinsic-constraint and stabilizing-selection hypotheses for conserved allometry. Large-bodied frugivores evolved faster than other species along the allometric trajectory, which could suggest stabilizing selection on the shape of the masticatory apparatus as body size changes.
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Affiliation(s)
- Luis D. Verde Arregoitia
- Instituto de Ciencias Ambientales y Evolutivas Universidad Austral de Chile Campus Isla Teja Valdivia CP 5090000 Chile
| | - Guillermo D’Elía
- Instituto de Ciencias Ambientales y Evolutivas Universidad Austral de Chile Campus Isla Teja Valdivia CP 5090000 Chile
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