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Spiny Boki Mekot Rat | Halmaheramys bokimekot
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Abstract
We describe Halmaheramys bokimekot Fabre, Pagès, Musser, Fitriana, Semiadi & Helgen gen. et sp. nov., a new genus and species of murine rodent from the North Moluccas, and study its phylogenetic placement using both molecular and morphological data. We generated a densely sampled mitochondrial and nuclear DNA data set that included most genera of Indo-Pacific Murinae, and used probabilistic methodologies to infer their phylogenetic relationships. To reconstruct their biogeographical history, we first dated the topology and then used a Lagrange analysis to infer ancestral geographic areas. Finally, we combined the ancestral area reconstructions with temporal information to compare patterns of murine colonization among Indo-Pacific archipelagos. We provide a new and comprehensive molecular phylogenetic reconstruction for Indo-Pacific Murinae, with a focus on the Rattus division. Using previous results and those presented in this study, we define a new Indo-Pacific group within the Rattus division, composed of Bullimus, Bunomys, Paruromys, Halmaheramys, Sundamys, and Taeromys. Our phylogenetic reconstructions revealed a relatively recent diversification from the Middle Miocene to Plio-Pleistocene associated with several major dispersal events. We identified two independent Indo-Pacific dispersal events from both western and eastern Indo-Pacific archipelagos to the isolated island of Halmahera, which led to the speciations of H. bokimekot gen. et sp. nov. and Rattus morotaiensis Kellogg, 1945. We propose that a Middle Miocene collision between the Halmahera and Sangihe arcs may have been responsible for the arrival of the ancestor of Halmaheramys to eastern Wallacea. Halmaheramys bokimekot gen. et sp. nov. is described in detail, and its systematics and biogeography are documented and illustrated.
Keywords: biodiversity; biogeography; Indo-Pacific; molecular systematics; morphology; Rattini; Wallacea
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Figure 1. Map of the Indo-Pacific Archipelago indicating contemporary islands, straits, seas, arcs, and faunal lines (modified from Lohman et al., 2011). Major islands are labelled; lineages of Murinae present on each island are also labelled; different countries in the Indo-Pacific are indicated by colours (see also Figs 2 and 3). Upper right: map of Halmahera Island, where a white star represents the trapping site of Halmaheramys bokimekot gen. et sp. nov. Maps were extracted and modified from Wikimapia (http://wikimapia.org).
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Figure 7. Colour drawing of Halmaheramys bokimekot gen. et sp. nov.
Watercolour by Jon Fjeldså.
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Family Muridae
Halmaheramys Fabre, Pagès, Musser, Fitriana, Semiadi & Helgen gen. nov.
Type species: Halmaheramys bokimekot Fabre, Pagès, Musser, Fitriana, Semiadi & Helgen sp. nov.
Etymology: Halmaheramys is named after its geographical provenance in the North Moluccas, as so far it is the only known murine genus that is endemic to the island of
Halmahera. We name the species after the type locality,
Boki Mekot, situated in the northern part of Weda Bay, to the north of Sagea village (00°36′42.60″ N, 128°2′49.00″ E). This mountainous area is facing environmental threats from mining and logging operations. By naming the new species after the type locality, we highlight the importance of this limestone-rich area for conserving Halmaheran endemic biodiversity.
Description: The genus is currently monotypic; see description for the species, below. Composition: The type species and only known member of
Halmaheramys is
H. bokimekot sp. nov. Additional species of
Halmaheramys are represented in the subfossil record of the island of Morotai, to the immediate north of Halmahera
(K.P. Aplin and K.M. Helgen, unpubl. data).
Natural history: In 2010, the mammalogical team of the MZB trapped six specimens of H. bokimekot gen. et sp. nov. in central Halmahera (Fig. 1), at a site located between 700 and 750 m a.s.l., in the southern part of Halmahera Island, north of Weda Bay. The type locality was situated at 723 m a.s.l. Boki Mekot is in a rugged hilly region, with dense primary lowland evergreen forest (Whitmore, 1987) and patches of open, old secondary growth (dominated by trees with small diameter trunks). No large rivers are within 15 km, but a small creek, with a gravel bed and slow, shallow water, remains active during the dry season. The soils have high nickel content, with thin humus (5–10 cm). The closest village is approximately 50 km from the trapping site. This is a mountainous area dominated by limestone and laterite. The surrounding highland rainforest is tall (≥ 30 m) and characterized by the following angiosperm families: Fagaceae (dominated by Lithocarpus species), Guttiferacea (nine species), Calophyllacea (dominated by Calophyllum species), Lauraceae (seven species dominated by Litsea species), and Myrtaceae (11 species dominated by Eugenia and Pometia species). Gymnosperms (Podocarpaceae), tree ferns, Ficus, rattans, bamboo, non-woody climbers, orchids, epiphytes, and bryophytes are also present (Sidiyasa & Tantra, 1984; Whitmore, 1987; Edwards et al., 1990; Flannery, 1995; Monk, Fretes & Reksodiharjo-Lilley, 1997). Specimens of H. bokimekot gen. et sp. nov. were captured in folding rat traps placed in runways beneath tree trunks lying on the ground, at burrow openings, and on tree trunks lying on or in subsurface spaces among tree roots. All specimens were trapped in primary forest. The bait consisted of roasted coconut and peanut butter. Halmaheramys bokimekot gen. et sp. nov. may be omnivorous, as stomach contents (n = 2) contained both vegetable and arthropod remains. Further study is needed in order to characterize the diet of Halmaheramys. Specimens collected at the type locality, between 10 and 15 January 2010 included three adult males with scrotal testes, and three adult females, one with an inactive reproductive tract and two with active reproductive tracts (one was pregnant with three embryos). At the type locality, H. bokimekot gen. et sp. nov. was trapped in association with R. exulans, R. morotaiensis, Phalanger ornatus (Gray, 1860), Suncus murinus (Linnaeus, 1766), and Viverra tangalunga (Gray, 1832).
Distribution: Known only from the type locality, Boki Mekot (Fig. 1). We predict that this rat will be found to be more widely distributed in appropriate forested habitats in Halmahera, and perhaps on adjacent islands with close Halmaheran biogeographic associations (e.g. Bacan, Morotai, Ternate, and Tidore).
Vernacular names: We provide vernacular names for H. bokimekot gen. et sp. nov., both in English (Spiny Boki Mekot Rat) and in Bahasa Indonesia (Tikus Duri Boki Mekot).
Pierre-Henri Fabre, Marie Pagès, Guy G. Musser, Yuli S. Fitriana, Jon Fjeldså, Andy Jennings, Knud A. Jønsson, Jonathan Kennedy, Johan Michaux, Gono Semiadi, Nanang Supriatna and Kristofer M. Helgen. 2013. A New Genus of Rodent from Wallacea (Rodentia: Muridae: Murinae: Rattini), and its implication for Biogeography and Indo-Pacific Rattini Systematics.
Zoological Journal of the Linnean Society. 169(2), 408–447; doi:
10.1111/zoj.12061
New Rat Species, Genus Described from Indonesia
A team of scientists from Indonesia, Denmark, France and the United States has discovered a new species and genus of rodent on the Halmahera Island in the Moluccan province, Indonesia.
New spiny rat discovered in 'birthplace of evolution'
