Parasite biogeography in the Australasian region.
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Eulimdana rauschorum n. sp. is described from southern black-backed gulls, Larus dominicanus Lichtenstein in Antarctica. The species is most similar to Eulimdana lari (Yamaguti, 1935) from Charadriiformes in the Holarctic. Males have spicules equal in length that are asymmetric in structure distally. There are 4-5 and 3-5 caudal papillae in rows to the right and left of the anus, and 2 small genital papillae at the posterolateral margin of the anus. Females have a variable number of prominent caudal papillae and large microfilariae (365 micron in length). The morphological similarities and host distribution of E. rauschorum and E. lari suggest they are sister taxa in which cladogenesis of the former accompanied the isolation and subsequent speciation of Larus dominicanus in the Southern Hemisphere.
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The methodology used in Phylogenetics remains one of the more interesting problems in comparative biology. Among the methods used, the cladistic is the most accurate. In the present case, among the Saurians, the characters chosen appeared early and cannot be referred to any adaptation bound to an evolutive progress. We have successively considered their distribution in the classification, their polarity and one phylogenetic hypothesis based on the Hennig's concepts. Such a work leads necessarily to systematical conclusions. For instance, we note the heterogeneity of some families. Among the Iguania, the Iguanidea are polyphyletics, the north-american forms breaking up from the other very early. Among the Scincomorpha, the Lacertilia result from two parts of different origins. This research verifies some systematic cuttings in the modern classification: among the Anguimorpha, the separation between Helodermatidea and the group, Varanidea-Lanthanotidea. The characters studied show a non-random distribution in the classification and show also some consistency with the geographical distribution of the extant Saurians. Therefore, it is important to search for the most parsimonious geographical hypothesis, which is in concern with the present data on the continental drift and generally on the history of the Earth, and which strengthens the cladograms posed from the selected characters.
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A list of the species and taxa of some pelagic animals from a tropical upwelling region, based on collections made off the coast of Costa Rica is presented. The list includes a total of 224 species, 53 genera and 11 subspecific forms in Cnidaria, Annelida, Mollusca, Artropoda (Crustacea), Chaetognatha and Pisces.
To predict the consequences of human-induced global climate change, we need to understand how climate is linked to biogeography. Energetic constraints are commonly invoked to explain animal distributions, and physiological parameters are known to vary along distributional gradients. But the causal nature of the links between climate and animal biogeography remain largely obscure. Here we develop a bioenergetic model that predicts the feasibility of mammalian hibernation under different climatic conditions. As an example, we use the well-quantified hibernation energetics of the little brown bat (Myotis lucifugus) to parameterize the model. Our model predicts pronounced effects of ambient temperature on total winter energy requirements, and a relatively narrow combination of hibernaculum temperatures and winter lengths permitting successful hibernation. Microhabitat and northern distribution limits of M. lucifugus are consistent with model predictions, suggesting that the thermal dependence of hibernation energetics constrains the biogeography of this species. Integrating projections of climate change into our model predicts a pronounced northward range expansion of hibernating bats within the next 80 years. Bioenergetics can provide the simple link between climate and biogeography needed to predict the consequences of climate change.
Evidence from molecular systematic studies suggests that many mushroom species may be quite ancient. Gene phylogenies were developed to examine the relationship between reproductive isolation, genetic divergence, and biogeography in oyster mushrooms (Pleurotus). Sequence data were obtained for two regions of DNA from populations belonging to eight intersterility groups (biological species). Phylogenetic analysis of sequences from the 5' portion of the nuclear encoded large subunit rDNA demonstrates an ancient origin for four intersterility groups of broad geographic distribution (world-wide), with a more recent radiation of several intersterility groups that are restricted to the Northern Hemisphere. An expanded analysis using sequence data from the more variable rDNA internal transcribed spacer region also reveals a phylogenetically based pattern of genetic divergence associated with allopatric speciation among populations from different continents in the Northern Hemisphere. The ability of rDNA sequences to resolve phylogenetic relationships among geographically isolated populations within intersterility groups illustrates the importance of biogeography for understanding speciation in Pleurotus. Patterns of geographic distribution among intersterility groups suggest that several species lineages evolved quite early, with recently evolved groups restricted to the Northern Hemisphere and older lineages occurring throughout the world. Based on phylogenetic evidence, analysis of historical biogeography using area cladograms shows that multiple dispersal and vicariance events are responsible for patterns of speciation observed.
AIMS: This botanical briefing examines how molecular systematics has contributed to progress in understanding the history of Tertiary relict genera, i.e. those that that now occur disjunctly in parts of Eurasia and N America, and how progress in understanding Southern Hemisphere biogeography paradoxically makes unravelling Northern Hemisphere biogeography more complex. SCOPE: Tertiary relict floras comprise genera of warm wet climates that were once circumboreal in distribution but are now confined to E Asia, south-eastern and western N America, and SW Eurasia. The intercontinental disjunctions among these genera have long been believed to result from land connections between Eurasia and N America, across Beringia and the N Atlantic. This view is reassessed in the light of new evidence for long dispersal of propagules across oceans being responsible for many plant disjunctions involving southern continents. The impact of molecular dating, which has been very different in Southern and Northern Hemisphere biogeography, is discussed. CONCLUSIONS: For N America-Eurasia disjunctions involving Tertiary relict floras, land connections remain the more likely cause of disjunctions but data from fossils or infraspecific variation will be required to exclude long-dispersal explanations for disjunctions in any individual genus. Molecular dating of divergence between disjunctly distributed Tertiary relict floras can tell us which palaeoclimatic or palaeogeographic events impacted on them, and how, but only if migration over land and vicariance can be proved and molecular dating is sufficiently accurate.
The interface of the Asian and Australian faunal zones is defined by a network of deep ocean trenches that separate intervening islands of the Philippines and Wallacea (Sulawesi, the Lesser Sundas, and the Moluccas). Studies of this region by Wallace marked the genesis of the field of biogeography, yet few workers have used molecular methods to investigate the biogeography of taxa whose distribution spans this interface. Some taxa, such as the fanged frogs of the ranid genus Limnonectes, have distributions on either side of the zoogeographical lines of Wallace and Huxley, offering an opportunity to ask how frequently these purported barriers were crossed and by what paths. To examine diversification of Limnonectes in Southeast Asia, the Philippines, and Wallacea, we estimated a phylogeny from mitochondrial DNA sequences obtained from a robust geographic sample. Our analyses suggest that these frogs dispersed from Borneo to the Philippines at least twice, from Borneo to Sulawesi once or twice, from Sulawesi to the Philippines once, and from the Philippines to Sulawesi once. Dispersal to the Moluccas occurred from Sulawesi and to the Lesser Sundas from Java/Bali. Species distributions are generally concordant with Pleistocene aggregate island complexes of the Philippines and with areas of endemism on Sulawesi. We conclude that the recognition of zoogeographic lines, though insightful, may oversimplify the biogeography of widespread taxa in this region.
Disjunct distributions have long fascinated biologists, particularly those found in the Southern Hemisphere. Gondwanan vicariance has been invoked to explain these patterns, with relatively limited studies having phylogenetically tested this hypothesis. Another intriguing pattern of disjunction involving South America is the American amphitropical distribution, where Western Hemisphere taxa have close relatives either north or south of the tropics. While better known in plants, this pattern is rarely proposed for animals and only phylogenetically tested in a handful of studies on hymenopteran insects. The Manticorini is a tribe of large-bodied, flightless tiger beetles whose members possess a complex distribution pattern attributable to both Gondwanan vicariance and American amphitropical disjunction. Using genomic-scale data we perform phylogenetic analyses to produce a time-calibrated evolutionary history of the Manticorini. With the resultant time tree we perform ancestral range reconstruction in order to recover the historical biogeography of this group. Our results show deep divergence between most manticorine genera, contrasted with young crown ages indicative of recent diversification. Our analyses support Gondwanan vicariance and amphitropical disjunction resulting from recent dispersal as part of the historical biogeography of the tribe. These findings highlight the role of both vicariance and dispersal in shaping diversification and complex modern distributions.
Late Miocene and Pliocene hominoids from Yunnan Province in southern China have been recovered from four sites or site complexes: Xiaolongtan, Yangyi, Shihuiba and Yuanmou. Of these, Shihuiba and Yuanmou are among the most prolific fossil hominoid sites in Eurasia, and they have yielded important evidence that is critical for documenting the evolutionary history, biogeography and paleobiology of later Neogene hominids. The aim of this paper is to clarify their taxonomy and nomenclature, and to present a preliminary synthesis of their phylogenetic relationships and biogeography. The morphological pattern and degree of variation observed in the fossil samples is consistent with there being a single, sexually dimorphic species represented at each site. Provisionally, we consider the Shihuiba, Xiaolongtan and Yuanmou samples to belong to two separate species within a single genus. The valid names for these species are Lufengpithecus lufengensis (from Shihuiba) and L. keiyuanensis (from Xiaolongtan and Yuanmou). From a phylogenetic perspective, the currently available evidence suggests that Lufengpithecus is either a primitive hominid that represents the sister taxon of the Ponginae+Homininae or a primitive sister taxon to the Ponginae. We tend to favor the second alternative, but acknowledge that a more comprehensive comparative analysis is needed to substantiate the phylogenetic and taxonomic affinities of Lufengpithecus. Importantly, the Yunnan fossil apes provide a unique temporal perspective on the evolutionary history of hominoids. Their continued occurrence during the late Miocene and Pliocene (approximately 8-2Ma), when hominoids became extinct throughout the rest of Eurasia, suggests that southern China (and presumably southeast Asia in general) was an important refugium for hominoids, including the ancestors of the orang-utans and gibbons. The uplift of the Tibetan plateau and its impact on regional climatic conditions may have been an important contributing factor in isolating the hominoids geographically and ecologically. We speculate that changed climatic condition in the mid-Pliocene, and possibly the arrival of Homo soon after, may have precipitated the regional extinction of large hominoids in southern China and in mainland southeast Asia.
The last four decades have seen an increasing integration of phylogenetics and biogeography. However, a dearth of phylogenetic studies has precluded such biogeographic analyses in South Asia until recently. Noting the increase in phylogenetic research and interest in phylogenetic biogeography in the region, we outline an integrative framework for studying taxon distribution patterns. While doing so, we pay particular attention to challenges posed by the complex geological and ecological history of the region, and the differences in distribution across taxonomic groups. We outline and compare three widely used phylogenetic biogeographic approaches: topology-based methods (TBMs), pattern-based methods (PBMs) and event-based methods (EBMs). TBMs lack a quantitative framework and utilize only part of the available phylogenetic information. Hence, they are mainly suited for preliminary enquiries. Both PBMs and EBMs have a quantitative framework, but we consider the latter to be particularly suited to the South Asian context since they consider multiple biogeographic processes explicitly, and can accommodate a reticulated history of areas. As an illustration, we present a biogeographic analysis of endemic Sri Lankan agamid lizards. The results provide insights into the relative importance of multiple processes and specific zones in the radiation of two speciose lizard clades.
The phylogenetic relationships of 106 European cyprinid taxa were determined based on the complete nucleotide sequence (1140 bp) of the mitochondrial cytochrome b gene. The molecular phylogeny was used (1) to revise the current systematics of European cyprinids, (2) to establish the phylogenetic utility of traditional morphological characters that are widely used in Cyprinidae systematics, and (3) to discuss alternative hypotheses on the biogeography of the family in Europe. The age of the major lineages within European cyprinids was tentatively estimated with a molecular clock and showed full agreement with the fossil record of the group. Moreover, the results provided unambiguous evidence for a close phylogenetic affinity of some Caucasian and Greek endemic cyprinid taxa (e.g., B. capito and B. brachycephalus and Leuciscus keadicus, Barbus graecus, and B. albanicus, respectively) to Iberian and North African, but not Central European, cyprinids. The existence of such unexpected phylogenetic relationships refutes the classical hypothesis on the biogeography of European cyprinids, which assumes a dispersal of the cyprinid fauna from central Europe to southern Europe and northern Africa during the Miocene (and, hence, predicts a close phylogenetic relationship of all Caucasian, Greek, Iberian, and North African cyprinids to central European taxa). Instead, the existence of a Mediterranean realm independent of the central European route seems plausible based on the molecular evidence. It is likely that the new biogeographical scenario proposed here might apply to other primary freshwater European animals with low dispersal abilities, including fish, amphibians, and invertebrates.
Studies of medium stomach worms (Subfamily Ostertagiinae) of domestic and wild ruminants in North America have refined our understanding of the systematics, host distribution and biogeography of these nematodes. Strong support for recognition of monophyly for the Ostertagiinae has resulted from preliminary phylogenetic analyses of morphological characters among these and other trichostrongylids. Evaluation of morphological and biochemical characters in our laboratory and elsewhere has not refuted the polymorphism hypothesis where paired major and minor morphotypes are postulated to represent polymorphic species within the genera Ostertagia (Ostertagia ostertagi/Ostertagia lyrata; Ostertagia leptospicularis/Ostertagia kolchida; Ostertagia gruehneri/Ostertagia arctica; Ostertagia mossi/Ostertagia dikmansi), Teladorsagia (Teladorsagia circumcincta/Teladorsagia trifurcata (= Teladorsagia davtiani), and Marshallagia (Marshallagia marshalli/Marshallagia occidentalis). The minor morphotype of Ostertagia bisonis, recognized in Eurasia (considered to be Teladorsagia kazakhstanica), has yet to be discovered in North America. The taxonomy of these species has remained stable since an earlier overview of Ostertagia spp. and Teladorsagia spp. in North American domestic stock at the 1986 Ostertagia Workshop. Investigations since 1986 have focused on comparative morphology and the clear differentiation of Ostertagiinae, primarily from wild ruminants, that have been reported or may potentially occur in domestic bovids. Among these are species which infect wild and domestic sheep (Marshallagia marshalli/Marshallagia occidentalis), bovids (Ostertagia bisonis), and cervids (Ostertagia mossi/Ostertagia dikmansi, Ostertagia leptospicularis/Ostertagia kolchida, Ostertagia gruehneri/Ostertagia arctica, Mazamastrongylus odocoilei and Mazamastrongylus pursglovei) in North America. A key is presented for identifying 15 species of the Subfamily Ostertagiinae that are parasitic in domestic and wild ruminants of North America. Four exotic species (Camelostrongylus mentulatus, Spiculopteragia spiculoptera (= Spiculopteragia boehmi), Spiculopteragia asymmetrica and Longistrongylus curvispiculum) have been reported in North America, but only in game farms and are not included in the key. Hyostrongylus rubidus, a member of the Ostertagiinae normally parasitic in pigs and only rarely reported from domestic ruminants, is not included in the keys. Additional data from comparative morphology and molecular analyses will promote a reassessment of the generic-level systematics of the Ostertagiinae and allow an evaluation of host-parasite evolution and historical biogeography.
The phylogenetic relationships and historical biogeography of 10 currently described rainforest skinks in the genus Saproscincus were investigated using mitochondrial protein-coding ND4 and ribosomal RNA 16S genes. A robust phylogeny is inferred using both maximum likelihood and Bayesian analysis, with all inter-specific nodes strongly supported when datasets are combined. The phylogeny supports the recognition of two major lineages (northern and southern), each of which comprises two divergent clades. Both northern and southern lineages have comparably divergent representatives in mid-east Queensland (MEQ), providing further molecular evidence for the importance of two major biogeographic breaks, the St. Lawrence gap and Burdekin gap separating MEQ from southern and northern counterparts respectively. Vicariance associated with the fragmentation and contraction of temperate rainforest during the mid-late Miocene epoch underpins the deep divergence between morphologically conservative lineages in at least three instances. In contrast, one species, Saproscincus oriarus, shows very low sequence divergence but distinct morphological and ecological differentiation from its allopatric sister clade within Saproscincus mustelinus. These results suggest that while vicariance has played a prominent role in diversification and historical biogeography of Saproscincus, divergent selection may also be important.