BOLL.ACC. GIOENIA SCI. NAT. Salticidae(Arachnida: Araneae) of New Guinea - a zoogeographicaccount ZABKA M. Z akl ad Z oolo gii WSR- P, 08- 1 I 0 Siedlc e, P olattd RIASSUNTO Malgrado la loro conune storia geologica,le connessioniterritoriali del pasmto,I'azione antropica e la vicinanzageografica, I'Australia e la NuovaGuinea hannouna fauna di Salticidimolto differente. Il numerodi generipresenti in Nuova Guinea d circa ugualea quello noto per I'Australia(50 e 58 rispettivamente), malgradola diversasupeficie delle due regioni.Per la Nuova Guineasono stati finora descrittiquindici generiendemici. Almeno sei generisono immigratidalle regioni tropicalidel VecchioMondo, alcuni altri sono ad ampia distribuzioneo cosmopoliti;cid sembrail risultatodella dispersione espansiva post-Miocenica. Parolechiave: Salticidae, Nuova Guinea, Generi endemici, Zoogeografia. SUMMARY Despitecommon geologicalhistory, past land bridges,human agencyand today's geographicalcloseness, New Guinea and Australia have surprisingly different salticid faunas. In spite of much smaller area the number of recorded generain New Guineais almostas largeas in Australia(50 and 58 respectively). The endemicsare representedby fifteen describedgenera. At least6 generaare Old World tropicalimmigrants, some others have wide or cosmopolitandistribution - both seemthe result of thepost-Miocene expansion or dispersion. Key words:Salticidae, New Guinea,Endemic genera, Zoogeography. General background New Guinea is one of most attractive model areas for lhe zoo- geographic research. The island is the second largest one in the world. It forms a link in a chain of archipelagoes stretching from Malayan Peninsula to the middle Pacific. As a part of the Australian tectonic plate New Guinea was separated from the Gondwanan supercontinent (at that stagebeing representedby the Antarctic plate only) some45-50 million years ago. In the mid-Miocene(15 m.y. B.C.) the Australianplate collidedwith the SundaIsland arc system,creating a temporaryland connectionfrom SE Asia to Australia,the only one in post-Gondwanan period (Ftlnwoon, 1984).The continuednorthward movement produced a disjunctionfrom the Sundalandplate and an oceanbarrier. During most of the geologicalhistory New Guinea and Australia formed one commonland. The presentseaway of the Tones Strait was established in the Pleistocene,some 6500-8000years ago. Thus, the whole area is derived from the complex interactionsbetween parts of the Australian plate and the Pacific and the Sundaarc system(Banrcw, 1981), resul- ting in an exchangeof faunisticand floristic elementsin both directions with differentintensity. New Guineaoffers a wide rangeof climates,habitats and great topo- graphicvariability. High mountainranges and isolatedvalleys of the tropics and subtropicshave the richestfaunas and floras and are known to be the areas of the most intensespeciation rate (ManrENS, 1979; PRoszvNs<t, 1980).At sea level the flora of New Guineais similar to that of the SundaArchipelago (BaRlow, 1981)but soulhwesternPapua is usually incorpbratedinto Australian floristic region becauseof re- semblancesof the open savannahsto that of N Australia. The floristic affinities of New Guineaand Australia also dependon altitudes,being more distinctiveat higher levels (Notftofagus,Araucaria, some species of Proteaceaeand Myrtaceae) and illustrating Gondwanan heritage. Platetectonics and Salticidae The influenceof plate tectonicson distributionare relatedto the age and dispersibility of the analysedtaxa (BERLAND,1934; LEGENDRE, 1979; LnurNEN, 1980; FILEwooD, 1984; BnrcGS, 1987; NIEDBaLA, I99I). Salticidaeare rather poor candidatesfor dispersion(HoRNeR, 197-5;SamoN & HoRNnn, 1977; ZABKA,1990). From the regiononly a few species,being the canopyinhabitants, are suspectedto haverelati- vely high dispersibility(ballooning?) (Zaera, 1991),few others,having pantropicalor transpacificdistribution, are likely to by dispersedby humanactivity. Almost all modernsalticid generaappeared in post-Oli- goceneperiod (WuNoenucu, 1986; WoLFF, 7990; Ztnt<d,, 1988) and, in contrastto some olher faunistic groups (Man, 1981a-b; 1982, FI- LEwooD, 1984), the Gondwananelements should not be expectedin 390 southerncontinents. The taxonomic research(see Zanfa, I99l) support this hypothesis.It can not be said, however, that the break up of Gondwanadid not affect today'ssalticids. It was the separationof the large land massesand its consequencesthat resultedin great climatic and floristic dissimilarityand influencedthe spider fauna. Salticidaeof Australia are the best example;the dominalionof Eucalyptr.tsformations provides unique conditions for evolution of highly endemic fauna (Zae<a, 1991). Commongenera and speciesin southerncontinents are not the result of geologicalpast but were establishedmore recentlyin naturalexpansion and humanactivity. The Miocenecollision of the Australianand Sundaplates brought to- gethertwo rich faunasand New Guineahas become the most activezone of faunistic exchangein latitudinal direction, in contrast to limited North-Southexchange. The dry habitatsof the Torres Strait and Sout- hern Papua and the extinctionof tropical rain forestsin large parts of NE Australia produceda very effectiveecological barrier for tropical rain forestdwellers in their expansiontowards Australia. In the opposite direction,the rain forestsof New Guineacreated a barrier for the ende- mic, dry adaptedAustralian salticids in their expansiontowards the in- land New Guineaand SE Asia. Zoogeographicelements The salticid faunaof New Guineaconsists of over -50described gene- ra (PnoszvNsKt, 1990; Zan,a, unpubl.), mosr of rhem with a large number of species.Depending on distributionalpatterns, few zoogen- graphicgrolrps can be separated. 1. Wide spread genera:Myrmaraclute, Afraflacilla, Bianor, Frigga, Harmocldrus, Hasarius, Menemerus,Plexippus, Portia, Thyene and Telamonia.Except for Myrmarachn.e,the other generaare represented by few s;recies.Some of them known to have cosmopolitan/pantropical representatives(Frigga, Hasaritts, Plexippus) that have spread to New Guinea due to human migrations. Judging from the present zoogeo- graphic and biological data, it seemslikely that some generamay have originatedin SE Asia and tropical Africa and expandedeastwards, ex- cept for Frigga being of SouthAmerican origin. 2. Indo-pacific genera:Bavia, Charippus, Cosmophasis(?), Cytaea, Palpelius, Plotius, Zenodorus (and related undescribedgenera). They rangefrom India to the westernPacific islandsand the northernAustra- 391 lia, occurringmostly in tropicalforests or secondaryhabitats. Their wide distribution seemspartly a result of floristic affinities and expansion- starting from the Miocene plate collision. Judging from the speciesdi- versity, some genera (Cytaea, Zenodorus) may be of New Guinean origin. The occurrenceof Cosmophasisoutside the Indo-Pacificarea has to be verifiedsince there is a possibilityof convergence. 3. Papuan genera:Allococalodes, Aruana, Bathippus, Cocalodes, Coccorche stes, D iolenius, E ury atttts, Furculattus, Hy ctiota, L eptatha- mas, Omoedus, Paraharmochirus, Poecillorclrcstes, Porius, Thorel- liola, Udvardya.Some are representedby a great numberof species(e. g. Coccorclrcstes) and seem to originate in the rain forests of New Guinea. They usually have few outside New Guinean representatives, from the SundaArchipelago to the middle Pacific,as a resultof the post- Miocene expansion.The Australian rangesseem to be the remnantsof former wider distributionthat includedtropical NE Queenslandand have beenreduced because of rain forestextinction. 4. Australian immigrants:Arasia, Helpis, Holoplatys, Ligonipes, Opistlnnctts, Sandalodes, Servaea, Simaetha, Simaethula, Sondra. Most generainhabit Eucalyptus formationsin the Port Moresby area. Somerepresentatives of Holoplatys andSondra can also be found under Araucaria bark or in rain forestleaf litter, respectively.Of all the com- mon generasome are widespreadand cosmopolitanand should not be consideredas a measureof affinities.Amongst over 30 generabeing of the Anstralian origin, only 10 are representedin New Guinea(Zeexa, 1991).At the specieslevel the percentageis evenlower. Acknowledgements Thanksare due to theOrganizing Committee of theXIVth EuropaeanCollo- quiumin Arachnology(University of Catania,Italy), especially to Prof.Teresa Cantarellaand Prof. Pietro Alicata for theirhospitality and financial support. Dr. J. Berry(Butler University, Indianapolis) is acknowledged for hiscritical rembrks on thetypescript. REFERENCES BARLow B. A., 1981 - TlreAustralian flora: its origin and evolutiott.ln: Flora of Australia, vol. I. George A. S. ed. Griffin PressLimited, Netley, pp.25-76. 392 BERLANDL., 1934 - Les Araigndes du Pacifique. In: Contribution a ldtude du peuplementzoologique et botaniquedes iles du Pacifique. Publ. Soc.biog6ogr., 4: 155-180. BRIGGSJ. C., 1987 - Antitropical distributiort and evolution in the Indo-West Pacific Ocean.Syst. Zool., 36:237-247. CUTLER8., 1984 - Late Oligoceneamber Salticidsfrom tlrc Doninican Repu- bhc. Peckhamia-2: 45-46. 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