Birds of paradise, biogeography and ecology in New Guinea: a review

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910 M. Heads Figure 37 Amaracarpus nummatus van Royen (Rubiaceae) (triangles), A. montiswilhelmi van Royen (hatched line), A. clemensae Merrill & Perry (continuous line). Figure 40 The distribution of Miniopterus p. propitristis Peterson and M. p. grandis Peterson (Chiroptera). Figure 38 The distribution of Tropidonophis parkeri Malnate and T. aenigmaticus Malnate (Serpentes). Figure 41 The distribution of Rhinolophus arcuatus Peters and Pipistrellus collinus Thomas (Chiroptera). Figure 39 The distribution of Neophascogale Stein and Phascolosorex Matschie (Marsupialia). Craton margin as stippled line. widespread on the cordillera are absent from the Papuan Peninsula. They used the term `Watut-Tauri Gap' to describe the biogeographical boundary between the birds of the Papuan Peninsula and those of the central Highlands of PNG, and this is the boundary correlated above with the craton margin. The exact location of this boundary remains uncertain: Frith & Beehler (1998) wrote that `The southeastern terminus of the distribution of Paradigalla, Pteridophora and Epimachus fastuosus is the Kratke Range. It is apparent there is some sort of distributional barrier southeast of the Kratke Mountains'. Likewise, they write that E. meyeri bloodi ranges east `presumably' to the Kratke Range. However, Frith & Beehler are only predicting the occurrence of these birds at the Kratke Mountains; their actual known limits are Goroka, Okapa, Okapa/Kainantu and Goroka, respectively, all lying even closer to the craton margin. The Kratke Mountains are nevertheless located at, or near, an important biogeographical boundary in the group, for example they mark the western limit of Paradisaea r. rudolphi (Fig. 30; cf. Piora Koster ± Fig. 33). Other birds such as Melidectes princeps range east to the Kratke Ó Blackwell Science Ltd 2001, Journal of Biogeography, 28, 893±925
Biogeography of birds of paradise 911 Mountains (Beehler et al., 1986), and are `strangely enough' (Rand & Gilliard, 1967) not represented in SE New Guinea. The Kratke Mountains are also an important centre for local endemics, such as the fern Grammitis silvicola Parris (Parris, 1983). Although they are relatively accessible they are still largely unexplored for birds of paradise. There are no records of birds of paradise from a potentially very interesting area between Mount Piora (Kratke Mountains) and Kerema. This region of 150 ´ 50 km is covered in rainforest, straddles the craton margin and includes the accreted ultrama®c Menyamya terrane (Pigram & Davies, 1987; not shown on the map of Bain et al., 1972). Parts of the Bismarck Range (Jimi and Benabena terranes) just north of the craton margin bear outlying populations of many taxa otherwise found only on the craton, for example Paradisaea rudolphi margaritae (Fig. 30). This could be the result of local range expansion across the terrane suture, or there may be a purely tectonic explanation: Pigram & Davies (1987) indicated that the Jimi and Bena Bena terranes (`stitched' together by the batholith which forms Mount Wilhelm) are probably displaced portions of the northern edge of the craton. The amount of displacement, if any, has not been determined. The Mount Wilhelm batholith, whether or not regarded as a separate terrane (Pigram & Davies, 1987 map it as part of the Australian craton) is separated from the craton by the Bismarck Fault Zone and is biogeographically distinct. The north coastal ranges The Idenburg, Sepik, Ramu and Markham Rivers form a 1300-km-long trough of structural origin separating the central New Guinea cordillera from the north coastal ranges. Gilliard (1969) wrote that `next to the central cordillera this depression is the most important zoogeographical barrier on the mainland of New Guinea'. The differences between the faunas of the central ranges and those of the north coastal ranges (e.g. Parotia lawesii compared with P. wahnesi) àre of the sort one would expect to ®nd on moderately isolated oceanic islands (which is perhaps what they once were), not on mountains situated 12 miles apart across a narrow valley!¼ Thus it seems that the Central Depression has, and is still playing an important part in the speciation of many lines of New Guinea animals'. While it is true that the depression marks an important biogeographical boundary, this may not have been caused by the depression as such but rather by the long-term tectonic history of the terranes in the region. It has been suggested that colonization across the Mamberamo-Sepik-Ramu-Markham gulch by midmontane birds has been `practically a one-way affair', from the central mountains to the small northern mountain islands (Diamond, 1972, 1985), but there is no real evidence for these invasions over current geography. The Vogelkop ± Huon disjunctions discussed above indicate that the situation is much more complex, and probably involves major tectonic changes. Drepanornis bruijnii has `the most anomalous' and ùnexplained' range in the Paradisaeidae (Frith & Beehler, 1998): lowlands of NW New Guinea north of the central depression from Geelvink Bay to Vanimo. However, a very similar distribution is seen in many birds, such as the ®g parrot Psittaculirostris salvadorii (Oustalet) (east Geelvink Bay to Cyclops Mountains by Jayapura) (Forshaw & Cooper, 1978; Beehler et al., 1986). One hypothesis Frith & Beehler (1998) cited for the distribution is that D. bruijnii differentiated in isolation in the north coastal ranges during a period of high sea-level that ¯ooded the basins of the Idenburg and Sepik Rivers. However, if the concept of accreted terranes is correct the regions north and south of the depression have been separated by much more than a simple ¯ooding of the current topography. The upper Watut Valley Epimachus m. meyeri ranges through the Papuan Peninsula north-west to Mount Missim, above the towns of Wau and Bulolo. Similarly, Manucodia keraudrenii purpureoviolacea Meyer ranges north-west to Wau, as does Lophorina superba minor where it meets L. s. connectens Mayr possibly endemic to the Herzog Mountains (although not recognized by Frith & Beehler, 1998). From the other direction, Loboparadisaea ranges through New Guinea, south-east to the nearby Herzog Mountains and Wau. As well as being a boundary, Mount Missim and the Herzog Mountains ( ˆ Mount Shungol) comprise a centre of endemism for bird subspecies in Mirafra, Pachycephala, Colluricincla, Melidectes, and Rhamphocharis (Rand & Gilliard, 1967). Plants in this upper Watut River region include Langsdorf®a Mart., known only from Mount Missim, Madagascar, and tropical America (Hansen, 1974; Streimann, 1983), and Hartleya, known only from Mount Shungol and Mount Kaindi with sterile specimens from the Vogelkop and its nearest relative, Gastrolepis Tiegh., in New Caledonia (Sleumer, 1971). There are as many as six Solanum species locally endemic in the upper Watut (Symon, 1985). Like E. m. meyeri, many plants endemic to SE New Guinea reach their north-west limit here, for example distinctive genera in Sapotaceae (Magodendron Vink ± Vink, 1995), Rubiaceae (Anthorrhiza Huxley & Jebb ± Huxley & Jebb, 1991) and Monimiaceae (Kairoa Philipson ± Philipson, 1980). The area is the northern limit of the Owen Stanley terrane schists, and is marked by mid-Tertiary intrusions, mainly granodiorite, which form the mountains bounding the Watut catchment: Shungol, Missim, Kaindi, and Amungwiwa. Each of these is a centre of endemism for different groups. Diamond (1972) interpreted the distribution of Lonchura species here as the result of recent, unpredictable colonization ± Àn extreme example of this irregularity occurs in the Herzog Mountains, where four different colonists occur at four different localities within 35 miles: L. tristissima in the Snake River valley, L. castaneothorax at Mumena [ˆ Mumeng] Creek, L. grandis at Biolowat [ˆ Bulowat], and L. spectabilis at Wau'. However, this local vicariance may be related to distribution of each species as a whole, and also to the complex tectonic history of the area. Ó Blackwell Science Ltd 2001, Journal of Biogeography, 28, 893±925
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Birds of paradise, biogeography and ecology in New Guinea: a review

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