SUPPORTING INFORMATION Biogeographical affinities of the New Caledonian biota:
a puzzle with 24 pieces Michael Heads
Journal of Biogeography
Appendix S1: Supplementary notes on New Caledonian biogeography This appendix includes notes on methods and on each of the 24 tracks described in the main text, an analysis of the terrestrial isopods of New Caledonia, and documentation of correlated local and global patterns for New Caledonian taxa.
Methods in historical biogeography Metapopulations and dispersal Van Balgooy et al. (1996, p. 210) concluded their discussion of Pacific Cupanieae (Sapind.) by writing that: ‘One can only detect that dispersal is involved, because the geological history of the Pacific is not consistent with the idea that all Pacific island groups together with Australia have formed one united area which has broken up in the course of time’. This denies ordinary, local dispersal in a metapopulation, but accepts extraordinary long distance dispersal.
Modern centre of origin/dispersal theory In their study of Pachycephalidae, Jønsson et al. (2010) calibrated the clock with endemics on Sangihe I., formed at 2-3 Ma, and Tanimbar I., formed at 1 Ma. To corroborate this first calibration, the authors used another rate, but this was also based on the assumption that an island endemic (Mimus graysoni) could be no older than its island (Socorro I. off western Mexico; Arbogast et al., 2006). As with the Indonesian islands, Socorro I. also occurs near an active plate margin and, again, the assumption that its endemics are no older than the island is very likely to give dates that are much too young. Any ‘corroboration’ between the two calibrations is meaningless. Although the spatial and chronological analyses of Jønsson et al. (2010) are not accepted here, the molecular phylogeny itself is of great interest.
The main clade in Pachycephala comprises three branches in an unresolved trichotomy: P. caledonica of New Caledonia (Grand Terre only, not Loyalty Is.), P. soror of New Guinea, and a large group ranging from Bangla Desh to Samoa, including New Guinea and New Caledonia (Grande Terre and Loyalty Is.). For P. caledonica, Jønsson et al. (2010) proposed a centre of origin in New Guinea and colonizing flights to New Caledonia, Bangla Desh, Samoa etc. But the centre of origin can be interpreted instead as a centre of differentiation in a widespread Bangla Desh – Samoa ancestor and long distance colonizing flights are unnecessary. Following initial vicariance of the three clades there has been secondary, local overlap in New Guinea and Grande Terre caused by terrane accretion, population expansion, or both.
In Pachycephala the second New Caledonian species is a form in the large Bangla Desh – Samoa group cited above, a subspecies of P. rufiventris found on Grande Terre. This was not sampled in the molecular study but probably has its closest relatives in Australia. Any overlap with P. caledonica within Grande Terre (distribution maps do not seem to be available) could be due to range expansion within the island following initial vicariance between P. caledonica and the large group that includes P. rufiventris.
The third New Caledonian Pachycephala also belongs to the large group cited above, and is a member of the diverse P.pectoralis species complex. This has a phylogeny: (Vanuatu (Bismarck Archipelago (Solomon Is. (Tanimbar I. (Australia))))). It also occurs in New Caledonia, but only on the Loyalty Is. and not on Grande Terre. Jønsson et al. (2010) interpreted the phylogeny as representing a colonization of the Melanesian arc from New Guinea (their Fig. 4 indicates colonization of Vanuatu from New Guinea via long distance dispersal north of the Bismarck Archipelago/Solomon islands, then the Bismarck Archipelago from New Guinea, then the Solomon Islands from New Guinea). Finally, there was a colonization of Australia from a centre of origin from somewhere in New Guinea/Pacific islands, where the basal grade occurs (cf. Rhipidura: track 6; monarch flycatchers, Filardi & Moyle, 2005). None of these dispersal events are necessary as the species are allopatric. In addition, dispersal does not explain the absence of the group from Grande Terre. The simplest explanation of the phylogeny is that it represents a series of differentiation events in an ancestor already widespread in Australia and the Pacific islands, including the Loyalty Is. but not Grande Terre. The biogeographical boundary between the Loyalty Is. and nearby Grande Terre is a standard one (cf. the plant Cyrtandra, Fig. 9) but is not explained in a dispersal model.
Documentation for the New Caledonia tracks For each area, notes on the treatment in the main text are given followed by information on lower plants, seed plants, invertebrates and vertebrates. Family names for seed plant families are abbreviated. Data is included for liverworts (Miller et al., 1983), mosses (Miller et al., 1978), higher plants (Council of Heads of Australasian Herbaria, 2009), Diptera (Evenhuis, 2005a), spiders (Platnick, 2007), birds (Dickinson, 2003), and other groups as cited.
Molecular evidence was used wherever available, but only for phylogenetic and geographical information; the chronologies of molecular clock studies were not accepted. Patterns are usually cited only if the groups they belong to seem to be reasonably well-collected. For example, disjunctions are usually only recorded if closely related taxa have been collected in the gap.
1. New Caledonia – south-westIndian Ocean Notes on the main text
Although Davis et al. (2002) invoked long-distance dispersal for Acridocarpus from Madagascar to New Caledonia, Davis et al. (2004) insisted that wind-dispersed Malpighiaceae fruit such as those of Acridocarpus ‘do not easily travel for long distances over water’ which argues against long-distance dispersal from Madagascar to New Caledonia, 10 000 km away. Another wind-dispersed member of Malpighiaceae, Hiptage myrtifolia, is a Fiji endemic most closely related to H. luzonica of the Philippines and Sulawesi, 6000 km away (Jacobs, 1955). Davis et al. (2002) considered the possibility that Acridocarpus has gone extinct in Australia due to aridity, but this is unlikely in a group that has flourished in Africa. Instead, populations may have been extirpated during subsidence of basins around the Timor Sea – Torres Strait region. Despite the problems with both long-distance dispersal and extinction, Davis et al. did not mention the main evidence for a vicariance explanation, the fact that the south-west Pacific Ocean – south-west Indian Ocean connection is a standard pattern.
Good’s (1950) account of ‘Madagascar and New Caledonia’ is a useful discussion of the topic but dispersalists have seldom mentioned the pattern; Thorne (1965) wrote simply that ‘Little significance can thus be accorded those taxa restricted to New Caledonia and the Malagasian region beyond their relict status...’. This does not account for the frequent vicariance observed between New Caledonia – south-west Indian Ocean groups and their northern relatives.
In algae, Millar & Bolton (2004) cited several species restricted to eastern Australia (New South Wales) and South Africa. The liverwort Cololejeunea ceatocarpa is in Réunion, New Caledonia and Hawaii, and C. cuneata is in Mauritius and New Caledonia (Miller et al., 1983). In liverworts, Cololejeunea cardiocarpa is in New Caledonia, Madagascar, southern central and East Africa, and southern United States/Greater Antilles.
In Phyllanthus (Phyllanth.), matK sequences link some New Caledonian members of subgen. Gomphidium with another New Caledonian clade of Phyllanthus (groups 6 and 7 of Aubréville et al., 1967-) (Kathriarachchi et al., 2006). The ITS tree instead places the New Caledonian Gomphidium with the Madagascan P. betsileanus (bootstrap support 92%). Kathriarachchi et al. (2006) regarded the New Caledonia – New Caledonia tie as ‘biogeographically more plausible’ than the New Caledonia – Madagascar disjunction and so they removed the ITS data of the Madagascan species from the combined (ITS and matK) matrix, nevertheless, the ITS affinity again fits the standard pattern.
Groups centred around the Indian Ocean include the trees in tribe Caletieae (Picrodendr.) of South Africa, Australia, Malesia, New Caledonia and Fiji (Radcliffe-Smith, 2001). The group is well-represented in New Caledonia, with four genera: Austrobuxus, Canaca, Longetia, Scagea. The last three are endemic to New Caledonia, while Austrobuxus has most of its species (14 out of 20) there.
In other angiosperms, Arthropodium (Antheric.) is in Madagascar, Australia, New Zealand, New Caledonia, and New Guinea (van Balgooy, 1971). Pigea etc. (= Hybanthus p.p.) (Viol.; Fig. 13) has a related pattern.
Disjunct clades between the south-west Pacific and south-west Indian Oceans include a group in Crossosomatales, Geissolomataceae (south-west South Africa) and its sister clade Strasburgeria (New Caledonia)/Ixerba (New Zealand). Korthalsella salicornioides (Visc.) is in Madagascar, New Zealand and New Caledonia (I. des Pins and Kouaoua, southern Grande Terre) (Aubréville et al., 1967; Molvray, 1997). The mainly Malesian/Pacific species Geniostoma rupestre (Logan.) has an outlier in the south-west Indian Ocean, G. r. var. borbonicum of the Mascarenes. It is closest to G. r. var. glaberrimum from New Caledonia and distinguishing the two ‘is often extremely difficult’ (Conn, 1980).
In other plants (data from Aubréville et al., 1967-), Agrostophyllum (Orchid.) is in Malaysia, Indonesia, Melanesia and Polynesia, with a single species in the Seychelles (A. occidentale). This last species is ‘very similar’ to the single species in New Caledonia. Cohnia (Lomandr.) is often accepted as a separate genus for the free-tepalled species otherwise placed in Cordyline. It occurs in New Caledonia and the Mascarenes (Conran, 1998). Cynorkis fastigiata (Orchid.) is known from the south-west Pacific (Fiji and Futuna) and the south-west Indian Ocean (Madagascar, Mascarenes, Seychelles) (Renz & Vodonaivalu, 1989). Cossignia (Sapind.) is in north-eastern Queensland, New Caledonia and Fiji, and disjunct in the Mascarenes (Smith, 1979-1996). Albizia guillainii of New Caledonia is not related to Asian or Australian congeners, but to African ones (sect. Zygia).
The large landsnail Placostylus ranges widely around the Tasman and Fiji basins (Lord Howe I., northern New Zealand, New Caledonia, Vanuatu, Fiji, and the Solomon Is.). Its sister, Bothriembryon, is in Tasmania and south-western Australia. The sister group of the pair is Prestonella of southern Africa (Herbert & Mitchell, 2008). The authors supported a vicariance interpretation for the pattern.
In the leafhopper family Myerslopiidae (Homoptera), one tribe (Sagmatiini) ranges in Madagascar, eastern Queensland, and New Caledonia, one is in vicariant in New Zealand/Chile, and one is endemic to Juan Fernandez Is. (related families are mainly diversified in continental Africa) (Hamilton, 1999). Hamilton concluded that the New Zealand – Chile tribe, at least, is ‘virtually certain’ to date from the break-up of Gondwanaland and so it would seem likely that the Sagamatiini are also a Mesozoic group.
The spider genus Pachyballus (Salticidae) is restricted to New Caledonia and Africa (in the south, east and west). New Caledonian members of Philoliche (Diptera: Tabanidae) are ‘unequivocally’ related to Afrotropical species and have their closest relative in P. pennata of Mauritius (Burger, 1995). Aselgeoides (Homoptera: Fulgoroidea) occurs in New Caledonia, and also in the Seychelles, Madagascar and Africa (Fennah, 1969). In Psocoptera, species of Phlotodes ‘Group II’ occur on New Caledonia, Fiji and New Guinea, and also in Madagascar (Thornton, 1981). A trochiform landsnail of Norfolk Island, south of New Caledonia, is closest to a Madagascan species (F.M. Climo, pers. comm., 2002).
The bivalve genus Funafutia (Lucinidae) occurs in the south-west Pacific (Queensland, New Caledonia, Kiribati, and Tuvalu) and also around Madagascar (Glover & Taylor, 2001) but is absent from western Australia (where other lucinid genera such as Pillucina occur).
The centipede Dichelobius shows a pattern: (Queensland (Western Australia + New Caledonia)) (Edgecombe & Giribet, 2004) which may be related to this pattern, and the spiders Epimecinus (Desidae) and Syrorisa (Desidae), and the ostracod Vestalenula marmonieri (Martens & Rossetti, 2002) are also restricted to New Caledonia and Western Australia.
A New Caledonia/India disjunction may also be related and is shown by several spiders: Penionomus (Salticidae) of New Caledonia and India, Stergusa (Salticidae) of New Caledonia and Sri Lanka, and Thomiscus leucaspis (Thomisidae) of New Caledonia and India, with the gap filled by T. spectabilis: India to Australia. Thomiscus otherwise ranges east to Java/Sulawesi, and is also in the Americas.
Fricke (2002) cited tripterygiid fish species with ‘bipolar west-east’ distributions, disjunct between the west Indian Ocean and the west Pacific Ocean, and ‘tripolar’ species (such as Enneapterygius elegans) which range around the Indian Ocean, Taiwan and the South Pacific, but have a broad gap in south-east Asia, western New Guinea and northern Australia.
This and similar examples indicate that the New Caledonia – Madagascar direct track is probably related to another: New Caledonia – New Guinea – Madagascar/Mauritius, which skirts Australia to the north, e.g. the group Weinmannia/Pancheria/Cunonia (Cunon.). Likewise, the marine mollusc Microvoluta joloensis ranges in New Caledonia, Fiji (Lau)/Tonga, and Wallis & Futuna (with related fossil forms in New Zealand), and is disjunct in the Philippines and Madagascar (Bouchet & Kantor, 2003).
2. Tethyan tracks: New Caledonia – Mediterranean Invertebrates
The lithistid sponge Siphonidium occurs in Florida, the Caribbean, the Azores, Western Africa, the Mediterranean, Indonesia, and New Caledonia (Manconi & Serusi, 2008).
3. Southern South Pacific track: Australia – New Zealand – New Caledonia – southern South
America Notes on the main text
Atherospermataceae (Laurales) are in eastern Australia/Tasmania (three genera), New Guinea (one genus), New Caledonia (one genus), and New Zealand-southern Chile (two genera). Fossil material is also known from the Kerguelen Plateau, the Antarctic Peninsula, Africa and Europe, but not America. The sister group is the family Gomortegaceae, with one genus in Chile (Heads, 2009c).
In the beetle group Adeliini (see main text) none of the four major areas occupied is confined to a single part of the phylogenetic tree and ‘This suggests that diversification had already occurred before the first area separated’ (Matthews, 1998). Fossil-based phylogeography and other dispersal analyses would instead infer that this indicated dispersal, but Matthews’ suggestion seems more likely.
In the Mesozoic, the fauna of the Murihiku terrane in New Zealand and faunas of equivalent terranes in New Caledonia and Argentina define a centre of endemism (Damborenea & Manceñido, 1992) which has persisted through the Cenozoic and is seen in many modern groups.
Libocedrus (Cupress.) of New Zealand and New Caledonia (fossil in south-eastern Australia) should include Pilgerodendron of southern Chile (Gadek et al., 2000).
Nothofagaceae, the southern beeches, are in Australia, New Guinea, New Zealand, New Caledonia and southern South America, with fossil records also in Antarctica (Heads, 2006).
In Proteaceae, a clade of seven genera form a mainly tropical track in eastern Australia – Melanesia – South America (Weston & Barker, 2006; Willis, 2007):
Hicksbeachia: eastern Australia, disjunct between Cairns area and the MMO (McPherson range to Coffs Harbour).
Euplassa: widespread in tropical South America.
Helicophidae (Trichoptera) are distributed in southern Australia, New Zealand, New Caledonia, Chile, and south-western Argentina (Johanson & Ward, 2001).
Members of the family Peloridiidae (Hemiptera) are found among mosses and liverworts, usually in Nothofagus forest, and occur in Australia, Lord Howe I., New Zealand, New Caledonia, and southern South America (Evans, 1981). Although no fossils are known, Evans wrote that the group represented an ‘undoubted ancient lineage [which] must have been in existence before the break-up of Gondwanaland’. The species are ‘remarkably stable and though their present populations must have been isolated for very considerable periods of time they have developed no substantial structural differences’.
In chrysomelid beetles, Spilopyrinae: Australia, New Caledonia, southern Chile, are sister to the world wide Eumolpinae (Gómez-Zurita et al., 2005).
In Agathis (Araucar.) the three main clades are allopatric in New Zealand (basal), Fiji-Vanuatu, and Australia (Knapp et al., 2007), with the New Caledonian and Malesian species probably to be included with the last (Page, 1980).
The tree Balanops, sole genus of Balanopaceae, ranges in Queensland (one species), New Caledonia (7 species), Vanuatu and Fiji (1). It is sister to a large pantropical complex (Trigoniaceae, Euphroniaceae, Dichapetalaceae, and Chrysobalanaceae; Stevens, 2009). Another basal group in the area is Melonycteris of the Bismarck Archipelago and Solomon Is., basal or near basal in fruit bats (widespread through the Old World) (Pulvers & Colgan, 2007). Other taxa based in and around the Coral Sea include the following.
Piliocalyx (Myrt.; New Caledonia, Vanuatu, Fiji) is sister to a clade of Acmena restricted to Cairns/Cape York (Craven et al., 2006; the taxa were treated in Syzygium s. lat.).
Santalum austrocaledonicum (Santal.) of New Caledonia and Vanuatu is sister to S. lanceolatum s. str. of Australia north of a line Broome – Townsville (Harbaugh & Baldwin, 2007; Harbaugh, 2007).
Zygogynum (incl. Bubbia, Belliolum and Exospermum) (Winter.) is in north-eastern Australia, Lord Howe I., New Caledonia, the Solomon Is., and mainland PNG (Vink, 1985).
Many Coral Sea groups have a massing in New Caledonia, for example, the family Myodocarpaceae, comprising the following three genera:
Myodocarpus: New Caledonia.
Pseudosciadium: New Caledonia.
Delarbrea: north-eastern Queensland, New Caledonia, Vanuatu, Solomon Is., New Britain, mainland PNG (Madang), Timor, and the Aru Is. (van Balgooy & Lowry, 1993; Plunkett, Wen & Lowry, 2004).
The three genera were formerly associated with Araliaceae/Umbelliferae, but are now regarded as closer to Pittosporaceae, a widespread Old World family. Plunkett et al. (2004) wrote that radiation of Araliaceae is ‘possibly correlated with the breakup of Gondwanaland’, which included the rifting open of the Coral Sea following the opening of the Tasman Sea.
Plant genera endemic here include the following.
Euroschinus (Anacard.): Queensland and New South Wales (1 species), New Guinea and New Britain (1), New Caledonia (4) (Avé & van Balgooy, 1984).
Storckiella (Caesalp.): Queensland (1 species), New Caledonia (3), and Fiji (1).
Archidendropsis (Mimos.): Queensland (3 species), northern New Guinea (1), Solomon Is. (1), New Britain (1), and New Caledonia (8) (van Balgooy & Nielsen, 1993).
Tapeinosperma (Myrsin.): eastern Australia (2 species), Solomon Is./ Bismarck Archipelago (4), New Caledonia (40), Vanuatu (2), Fiji (12), Tonga (1) (not in New Guinea) (van Balgooy, 1993d).
Related species of Dasybasis (Diptera: Tabanidae) form a series surrounding the Coral Sea, in eastern Australia, PNG, Bismarck Archipelago, Solomon Is. (including Santa Cruz Is.), and New Caledonia (Mackerras, 1970).
5. Tasman Basin Lower plants
Groups restricted to New Zealand – Tasmania with a northern outlier at New Caledonia include the liverworts Adelanthus bisetulus: Tasmania/Victoria, New Zealand (including the subantarctic Auckland and Campbell Islands) and New Caledonia, Acrochila: Tasmania, New Zealand, New Caledonia, Tetracymbaliella, the same range plus Campbell I. (Schuster, 1979, 1982), and Cephaloziella exiliflora: Tasmania, New Zealand, and New Caledonia.
In the fern Gleichenia/Stromatopteris, a New Zealand, Tasmania, New Caledonia clade was retrieved in the sample of species studied by Perrie et al. (2007).
In Atherospermataceae, Nemuaron of New Caledonia is sister to Atherosperma distributed from north-eastern New South Wales to Tasmania (Renner et al., 2000).
Some groups have most of their species around the Tasman Sea but also occupy north-eastern Queensland. For example, Dracophyllum (Eric.): eastern Australia (Tasmania to north-eastern Queensland), New Caledonia, Lord Howe I., New Zealand including the Subantarctic islands (most species) (van Balgooy, 1966a, Heads, 2009c).
Hedycarya (Monim.) is in eastern Australia (Victoria to north-eastern Queensland; not in Tasmania) (2 species), New Caledonia (8 species), Vanuatu, Fiji/Tonga/Samoa (1) and New Zealand (1) (van Balgooy, 1993c).
In Diptera, Chrysopilus tasmaniensis (Rhagionidae) is in New Caledonia and Tasmania.
In beetles, Percosoma (Carabidae) comprises two species in Tasmania and one in New Caledonia (Roig-Juñent, 2000) and belongs to a subtribe that is also in New Zealand (Mecodema etc.), Australia and South America. Other subtribes are in other parts of the world and as Roig-Juñent (2000) concluded: ‘From a biogeographical point of view, the idea of either an austral or Holarctic dispersal center of origin is not supported. The tribe was probably distributed along the Pacific margin in the Jurassic’.
Groups extending further north in Australia include the basal clade in the world-wide Micropterigidae (basal Lepidoptera). The clade comprises 11 species in Tasmania and along the east coast of Australia (north to Daintree near Cairns), two species in New Caledonia, and one in northern North Island, New Zealand (Gibbs, 1990, 2006; G. Gibbs pers. comm. 7 – viii – 2007).
The spider Migas (Migidae) is in New Zealand (most species), Tasmania, Queensland, and New Caledonia.
6. New Caledonia – Australia Seed plants
Canarium sect. Canariellum (Burser.) is in New Caledonia and Queensland: Townsville – Brisbane (Leenhouts, 1955). Archirhodomyrtus (Myrt.), formerly regarded as endemic to New Caledonia is now taken to include A.(Rhodomyrtus) beckleri of north-eastern New South Wales – north-easterrn Queensland by (Scott, 1978). Taxa with distributions that are similar but more widespread in eastern Australia include the snapper Lutjanus adetii which occurs along the New South Wales/Queensland coast and in New Caledonia (Allen, 1985) and the tree Sannantha (Myrt.) of Queensland – Victoria (10 species) and New Caledonia (4 species) (Wilson et al., 2007).
Alectryon (Sapind.) ranges from south-east Asia to Australia and through the Pacific islands to Hawaii. New Caledonia has one (endemic) species. Edwards & Gadek (2001) accepted a ‘Gondwanan origin’ of the genus, but interpreted New Zealand and New Guinea members as the result of dispersal and presumably the New Caledonian species (not included in their study) would also be interpreted as due to dispersal. The only evidence given for dispersal was the cladogram topology and this can be interpreted instead as representing a sequence of vicariant events in a widespread ancestor.
‘All Australia’/southern New Caledonia distribution is seen in the clade Actinostrobus/ Callitris/Neocallitropsis (Cupress.) (Gadek et al., 2000).
For Araucariaceae, Givnish & Renner (2004) began by inferring an Australian origin followed by ‘expansions’ into other islands of the south-west Pacific, including ‘at least two colonizations of New Caledonia by Agathis and Araucaria’. But after considering other paleobotanical and ecological data, Givnish & Renner concluded that ‘it is impossible to infer whether Agathis arose in Australia, Malesia, New Caledonia or any combination of these regions… Additional detailed paleobotanical data from Malesia and New Caledonia will be needed to resolve this issue.’
Another branch of Myrtaceae is the Melaleuca group of New Caledonia, Australia, New Guinea, and neighbouring areas. The New Caledonian taxa again form a clade that may be basal, ‘representing a relatively old vicariance event as for the eucalypt group’ (Ladiges et al., 2003).
Bartish et al. (2005), Swenson, Bartish & Munzinger (2007), and Swenson, Munzinger & Bartish, 2007) found several clades of Sapotaceae each comprising a single Australian species sister to a relatively large group of New Caledonian endemics, ‘suggesting multiple dispersal events’ between the two countries.Bartish et al. (2005) wrote that ‘the phylogeny suggests an interesting case of a relatively recent and rapid radiation of several lineages of Sapotaceae within New Caledonia’. The basis for their molecular clock calibration of the molecular dating was not mentioned, but was based on dates in Richardson et al. (2001). Richardson et al., in turn, did not mention the basis for the calibration and the rates were again derived from another paper.
With respect to the Australia-New Caledonia Sapotaceae, repetitions of a particular disjunction, as in this case, can usually be interpreted as evidence for vicariance. For instance, discussing a disjunction between Tennessee and Arkansas in a Carex species, Naczi et al. (1998) concluded that ‘The repeated examples of this distribution pattern suggest that the disjunction of C. willdenowii in the Ouachita Mountains is not due to natural long-distance dispersal nor to introduction by humans’.
With respect to the bird family Aegothelidae and its proposed centre of origin (see main text), Dumbacher et al. (2003) wrote that the New Caledonia and New Zealand species could have ‘arrived at any time on their respective landmasses’. The basal position of the New Caledonia-New Zealand pair in the phylogeny ‘raises the question of whether owlet-nightjars dispersed to these islands at a time when they were closer to Australia’. In fact there is no need for any ‘arrival’ or ‘dispersal’ across the Tasman Sea either eastwards or westwards; eastern and western clades probably evolved in the regions they currently occupy.
In species of Megalosporaceae (lichens), the tuberculosa-type of spore occurs in Australian species but is absent from Lord Howe, New Zealand and New Caledonia, while atrorubicans- and sulphurata-types show the reverse situation. There is a single exception for each spore type (Sipman, 1983).
An example from the fauna of a diverse Australian group absent from New Caledonia is the gastropod family Bithyniidae (Ponder, 2003).
The diving beetle genus Papuadytes has 20 species in Australia, 150 in New Guinea, and 30 in New Caledonia, but is not in Fiji, whereas the related Copelatus has related extensively in Fiji, but is not in New Caledonia. For Balke et al. (2007a) this indicates that ‘whether or not a lineage is on an island is due to chance’, but instead it is a simple case of vicariance between Australia/New Guinea/New Caledonia on one hand and Fiji on the other. Balke et al. (2007a) recovered a phylogeny for Papuadytes: (Australia (New Caledonia (Australia (Australia (New Guinea (China (New Caledonia, Australia))))))). They wrote that the New Caledonian fauna is composed of two clades each with a sister group in Australia. But their cladogram indicates that the more basal New Caledonian clade is sister to a large group of Australia, New Guinea, China and New Caledonia, indicating an early divergence and subsequent overlap. The authors suggested that dispersal has played an important role in the history of Papuadytes, but the molecular clock dates were the only evidence for this. The clock was calibrated on the basis that central Australian taxa diverged at 10 Ma. This date was based on a date for other central Australian beetles living in the same locality and the same groundwater habitat. The basis for this date was not given. In any case, this procedure of ‘ecological cross calibration’ is very prone to error as taxa often persist in a changed habitat.
In flies, the predominantly Australian genus Australophlebotomus (Psychodidae) has a ‘derived’ species pair in New Caledonia that could be the result of Paleocene vicariance (Léger & Depaquit, 2002, as cited by Cranston, 2005). Another fly genus, Antyx (Dolichopodidae), is known from the Blue Mountains (by Sydney), the McPherson-Macleay Overlap (see section 7), north-eastern Queensland, and New Caledonia (Bickel, 1999). Bickel suggested a ‘minimum late Cretacous age’ and ‘vicariant Gondwanan’ origin for the genus.