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Apomys, a Philippine endemic genus of forest mice, occurs throughout most oceanic portions of the archipelago and is its most speciose mammal genus, with 18 species currently recognized. Recent extensive surveys of mammals on Mindoro Island have produced specimens that document the presence of three genetically and morphologically distinct candidate species of Apomys (subgenus Megapomys) previously unknown. These three, plus one previously described relative from Mindoro, constitute a clade of well-supported, reciprocally monophyletic units based on cytochrome b sequence data, all of which are strongly supported using BPP species delimitation. Data from three nuclear genes show less divergence, but species delimitation analyses are consistent with results from cytochrome b. These four taxa are easily diagnosed on the basis of pelage and cranial morphology. Each of the four species occurs allopatrically, though two occur along a single elevational gradient. In this paper, we formally describe the three new species. We estimate that the common ancestor of the four species arrived on Mindoro from Luzon roughly 4.7 Ma, with initial diversification beginning roughly 2.7 Ma, and increasing to the current four species about 1.3 Ma. The three new species increase the number of mammals currently recognized as endemics on Mindoro from nine to twelve. This is a remarkably high number of endemic mammals from an island of its size, and reflects Mindoro’s status as a geologically old island permanently isolated from other oceanic islands in the Philippines by deep water, while also corroborating Mindoro as the smallest island within which endemic speciation by small mammals is known to have occurred.
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Three new shrews (Soricidae: Crocidura ) from West Sumatra, Indonesia: elevational and morphological divergence in syntopic sister taxa
Abstract We describe 3 new species of shrews (Eulipotyphla, Soricidae, Crocidura) from West Sumatra, Indonesia. Two of these taxa were found above 1,800 m on Mt. Singgalang. The third taxon was found above 1,660 m on Mt. Talamau, 65 km northwest of Mt. Singgalang. We also resurrect Crocidura aequicauda based on 2 specimens from Mts. Tujuh and Kerinci, which lie near the border between West Sumatra and Jambi provinces. Several methodological approaches support our findings: linear cranial morphometrics, landmark-based 2D geometric morphometrics, and molecular phylogenetics using both mtDNA and 6 nuclear exons. A multilocus species-tree analysis places the 3 new species and C. aequicauda in a clade with the Javan endemics C. monticola and C. umbra. Although the 2 taxa from Mt. Singgalang are recovered as sister species, 1 is nearly twice the size of the other, and they are divergent in several other morphological characters, such as tail length, cranium size, and pelage color and texture. Recently diverged yet morphologically disparate sister taxa living syntopically in an isolated habitat “island,” like the montane forests of Mt. Singgalang, is unusual in mammals but documented in other Crocidura on neighboring Java and Borneo; these 2 new taxa represent the first known case of this phenomenon on Sumatra. Our results bring the number of Sumatran Crocidura to 10, 9 of which are endemic to the island. All 3 of the new species appear to be endemic to a single mountain and were not detected in similar surveys of nearby mountains. If this local endemism pattern is common, it would indicate that Sumatra’s mammal diversity may be severely underestimated, largely due to the paucity of small-mammal surveys and museum specimens.
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- PAR ID:
- 10487600
- Publisher / Repository:
- Oxford University Press
- Date Published:
- Journal Name:
- Journal of Mammalogy
- Volume:
- 105
- Issue:
- 2
- ISSN:
- 0022-2372
- Format(s):
- Medium: X Size: p. 372-389
- Size(s):
- p. 372-389
- Sponsoring Org:
- National Science Foundation
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