"Philosciidae" (Crustacea: Isopoda: Oniscidea)
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Org. Divers. Evol. 1, Electr. Suppl. 4: 1 -85 (2001) © Gesellschaft für Biologische Systematik http://www.senckenberg.uni-frankfurt.de/odes/01-04.htm Phylogeny and Biogeography of South American Crinocheta, traditionally placed in the family "Philosciidae" (Crustacea: Isopoda: Oniscidea) Andreas Leistikow1 Universität Bielefeld, Abteilung für Zoomorphologie und Systematik Received 15 February 2000 . Accepted 9 August 2000. Abstract South America is diverse in climatic and thus vegetational zonation, and even the uniformly looking tropical rain forests are a mosaic of different habitats depending on the soils, the regional climate and also the geological history. An important part of the nutrient webs of the rain forests is formed by the terrestrial Isopoda, or Oniscidea, the only truly terrestrial taxon within the Crustacea. They are important, because they participate in soil formation by breaking up leaf litter when foraging on the fungi and bacteria growing on them. After a century of research on this interesting taxon, a revision of the terrestrial isopod taxa from South America and some of the Antillean Islands, which are traditionally placed in the family Philosciidae, was performed in the last years to establish monophyletic genera. Within this study, the phylogenetic relationships of these genera are elucidated in the light of phylogenetic systematics. Several new taxa are recognized, which are partially neotropical, partially also found on other continents, particularly the old Gondwanian fragments. The monophyla are checked for their distributional patterns which are compared with those patterns from other taxa from South America and some correspondence was found. The distributional patterns are analysed with respect to the evolution of the Oniscidea and also with respect to the geological history of their habitats. Species that were probably introduced are marked with an asterisk (*), nomina dubia are marked with an accent (^). Key words: Crustacea, Isopoda, Oniscidea, Crinocheta, phylogenetical systematics, phylogeny, biogeography, Neotropis, South America Contents 1 Introduction .................................................. 2 6 Biogeographical Section ............................... 63 2 History .......................................................... 3 6.1 Geological and Geographical Background ... 63 3 Material and Methods ................................... 5 6.2 General Aspects ............................................ 67 4 Taxonomic Section ....................................... 8 6.3 Tropical Central America and Caribbean ..... 68 4.1 Phylogenetically Informative Characters ..... 8 6.4 Neotropical South America .......................... 69 4.2 Generic Account ........................................... 23 6.4.1 Andean Amazonas Subregion ...................... 71 4.2.1 The South American Genera ........................ 23 6.4.2 Caribbean Amazonas Subregion .................. 72 4.2.2 Nomina dubia ............................................... 51 6.5 Temperate South America ............................ 73 4.2.3 Genera used as Outgroups ............................ 51 6.6 Littoral and Introduced Taxa ........................ 74 4.3 Key to the Genera of "Philosciidae" 6.7 Faunal Exchange between North and of the New World ........................................ 52 South America ............................................. 74 5 Phylogeny of South American 7 Summary ...................................................... 75 "Philosciidae" .............................................. 53 8 Acknowledgements ...................................... 76 5.1 Evolution of Lung Structures ....................... 53 9 References .................................................... 76 5.2 Phylogenetic Reconstruction ........................ 54 1 Welsingheide 160, 48163 Münster, Germany, e-mail: [email protected] Org. Divers. Evol. 1, Electr. Suppl. 4 (2001) Leistikow: Phylogeny and Biogeography of South American „Philosciidae“ 2 1 Introduction family (Leistikow and Wägele 1999). It is confined to moist areas whereas the Armadillidae are adapted to The taxon Oniscidea plays an important role in the drier habitats (Taiti et al. 1998). While we have a decomposition of organic material within the terrestrial considerable understanding of the diversity of "Philos- biota. They can occur in high densities, comprising the ciidae" in Africa (Taiti and Ferrara 1980, Taiti and bulk of terrestrial detritivores with numbers of up to Ferrara 1982, Ferrara and Taiti 1985), the islands in 500 individuals per square meter (Davis 1984). In the Indian Ocean (Barnard 1964, Ferrara and Taiti South America, they are found in tropical ecosystems 1983, Taiti and Ferrara 1984), South and South East where they are both terrestrially and arboreally dis- Asia (Taiti and Ferrara 1986b, Manicastri and Taiti tributed (Picardo 1913, Paoletti 1989, Nadkarni and 1987, Taiti and Manicastri 1988, Green et al. 1990, Longini 1990). Their contribution to the consumption Taiti et al. 1992) and the Australian region (Herold of decaying plant material may be up to 12% (Grün- 1932, Verhoeff 1926, Vandel 1973a, 1973b, 1977), wald 1988), thus they play an important role in soil there are only few contributions to the systematics of formation. Although they are ubiquitous, little is "Philosciidae" from South America. Particularly, the known about their life history and the phylogeny of early works on neotropical "Philosciidae" (Dollfus this interesting suborder of the Isopoda. The Oniscidea 1893, Budde-Lund 1893, van Name 1936) did not deal is the only truly terrestrial taxon of the Crustacea. with supra-generic systematics; and even the attempts The oniscidean fauna of Europe is well documen- of Lemos de Castro (1958a, 1958b, 1958c, 1976, ted; and an identification key for the approximately 1985b) and Vandel (1952, 1963, 1968, 1972) did not 1230 nominal species is available (Schmölzer 1965), clarify the situation convincingly. In a relatively recent although new species and even genera are still being work on Mexican Oniscidea (Mulaik 1960), most discovered (e.g. Schmalfuss 1998a). A survey of Afri- "Philosciidae" were simply placed in the genus Philos- can Oniscidea listed 575 species (Ferrara and Taiti cia, although this genus is in fact confined to the 1979). For the Americas, a number of 254 species of western Palearctic (Schmalfuss 1990b). terrestrial Isopoda was given by van Name (1936) and This study aims to establish monophyletic taxa for several more were listed in subsequent publications the South American species showing a philosciid fa- (van Name 1940 and 1942). A recent survey led to an cies. The species and genera were described in the past increase to up to 521 described nominal species in in a very superficial way and many characters have 1997 (Leistikow and Wägele 1999). But this is only been overlooked. Until very recently, sexual dimor- the tip of the iceberg since every expedition to the phism for example was thought to be restricted to the tropical rain forests reveals new species and even pereopods 1 and 7, whereas recent thorough descrip- genera. tions gave evidence to the fact that almost all pereo- Up to now, about 4000 species of Oniscidea are pods might be affected by sexual differentiation known, half of all known isopods (Gruner 1993). (Schmidt 1998; Leistikow 1999a). The detailed study Apart from some smaller taxa, the suborder is of the species of all accessible genera from South subdivided into the monophyletic adelphotaxa Syn- America are the basis for new definitions of these ocheta and Crinocheta, the latter comprising the bulk genera in the last years (Leistikow 1997b, 1998a-c and of the species. A summary of the attempts made in the 1999a-c, 2000a-b, 2001a-f, in press). Additional new last years to establish a phylogenetic system of the species for many taxa could be identified (Leistikow, higher taxa of Oniscidea was given by Erhard (1998). 1997a, 1999c and d). The question whether all South Until recently, the phylogeny within the Crinocheta American representatives of the so-called family "Phi- had been poorly studied, with almost every known losciidae" belong to a single monophylum or whether family forming a paraphyletic assembly rather than re- they represent different monophyletic groups will be flecting the natural relationships within this taxon (H. discussed. For the taxa recognised, the biogeographic Schmalfuss, pers. comm.). New insight into the phylo- patterns will be traced on an inter- and infracontinental geny of this group was provided by Schmidt (1999). scale. For the higher taxa, the biogeography is dis- Among the Crinocheta, about one hundred genera cussed with regard to the colonisation of Gondwana in are placed in the so-called family "Philosciidae", the comparison to other biogeographic scenarios presented phylogeny of it has not been discussed sufficiently yet. in the literature (e.g. Vandel 1946). The general infra- This basal group is, besides the Armadillidae, one of continental patterns worked out will be compared with the most important groups of Oniscidea in tropical patterns known from other invertebrate and vertebrate habitats (Schmalfuss 1984a: 12), in South America taxa. Fortunately, South America is well-studied bio- about one fifth of the nominal species belong to this geographically. Org. Divers. Evol. 1, Electr. Suppl. 4 (2001) Leistikow: Phylogeny and Biogeography of South American „Philosciidae“ 3 In order to make the determination of South Ameri- female specimens.