Nucleolar organiser region (NOR) location in karyotypes of Australian ground frogs (family Myobatrachidae)

Nucleolar organiser regions (NORs) were examined in over 90% of the species of Australian ground frogs (familiy Myobatrachidae), including representatives from all twenty currently recognised genera and the three subfamilies. Throughout the family, location of the NOR within the karyotype showed considerable variation yet karyotype morphology showed uniformity. The precise mechanism(s) whereby variation in NOR location evolved while karyotype morphology was unchanged remains uncertain. Comparison of the two major subfamilies showed that the Limnodynastinae had a greater diversity of NOR location than the Myobatrachinae. The limnodynastine genus,Heleioporus, was the only one to show multiple NOR sites in several species. NOR location was particularly stable within most polytypic genera. Differences in NOR location within the remaining polytypic genera (Heleioporus, Limnodynastes, Neobatrachus, Philoria andRanidella) pointed to taxonomic discriminations that were generally consistent with recent proposals based on other criteria.     

Phylogenetic Relationships among Bufonoid Frogs (Anura: Neobatrachia) Inferred from Mitochondrial DNA Sequences

Nucleotide sequences of portions of the mitochondrial 12S and 16S ribosomal RNA genes were used to extend a recent study of anuran phylogeny (Hayet al., Mol. Biol. Evol.12: 928–937, 1995) and to further evaluate phylogenetic relationships within the Neobatrachia. An analysis of almost 900 nucleotides from each of 8 new representatives of the Dendrobatidae, Hylidae, Leptodactylidae, and Myobatrachidae, plus 14 available members of the Neobatrachia provides support for 2 major lineages (Bufonoidea and Ranoidea) within this anuran suborder. The neotropical Bufonoidea and their derivatives are monophyletic. There is an interesting association of the 2 Australian myobatrachids with the South African Heleophrynidae, and the Sooglossidae is one of the basal bufonoid lineages. Within the New World bufonoid frogs, a monophyletic Dendrobatidae is strongly supported. An Australian hylid (Pelodryadinae) shows close affinity with the South American hylid Phyllomedusinae. A group composed of Hylinae (HylaandSmilisca), Centrolenidae, Bufonidae, and the hylid Hemiphractinae, with the latter two clustered, was supported significantly. The addition of new taxa has more clearly defined some relationships within the suborder Neobatrachia and has indicated that the families Hylidae, Leptodactylidae, and Myobatrachidae may not be monophyletic.     

The ultrastructure of the spermatozoa of bufonid and hylid frogs (Anura, Amphibia): implications for phylogeny and fertilization biology

Comparison of the spermatozoa of Bufo marinus , six Australian species of the family Hylidae, and the myobatrachine Adelotus brevis , with those of 41 other species of frogs, in a total of 12 investigated families allows the following phylogenetic inferences: the bufonoids (myobatrachids, leptodactylids, hylids, and bufonids) form a monophyletic assemblage with a single synapomorphy: the presence of a conical subacrosomal perforatorium. This structure is analogous to, rather than homologous with, the perforatorium in archaeobatrachians, which differs notably in being an endonuclear structure. The hylid-leptodactylid-bufonid assemblage is the sister-group of the Myobatrachidae (Australian 'leptodactylids'). Myobatrachids are distinguished by two. albeit weak, synapomorphies, the presence of well-defined pericentriolar material, and the extension of the axial rod up the centriolar fossa, the latter condition approached in the bufonid Nectophrynoides. The bufonid, leptodactylid ( sensu strictu ), and hylid families are united, and separated from myobatrachids, by a single synapomorphy: a thick collar-like cytoplasmic sheath that emanates from the centriolar region, is separated from the flagellum by a cytoplasmic canal, and contains the mitochondria. Litoria fallax, L. gracilenta , and L. lesueuri are associated by a unique synapomorphy, hypermorphosis of the minor fibre (juxta-axonemal fibre), though this is approached in Bufo bufo. However, there is no spermatological evidence supporting the recognition of Australian hylids (pelodryadids) as a group distinct from the remaining eubufonoids and, specifically, from the Hylidae. Evidence is presented in support of the tentative proposal that the Lissamphibia were primitively internally fertilizing.     

Sperm competition selects for increased testes mass in Australian frogs

Game theory predicts that investment in spermatogenesis will increase with the risk and intensity of sperm competition. Widespread support for this prediction has come from comparative studies of internal fertilizing species reporting positive associations between testes mass and the probability that females mate with more than one male. Data for external fertilizers have generated conflicting results. We investigated how risk of sperm competition affects testes size in two families of Australian frogs: the Myobatrachidae and the Hylidae. We also examined effects of clutch size, egg size and oviposition location as alternative factors that might influence sperm production. Species were ranked according to probability of group spawning, and hence risk of sperm competition. Controlling for body size and phylogenetic relationships, we demonstrated that within the Myobatrachidae, the risk of sperm competition explained a significant amount of variation in testes mass. Oviposition location had a weak influence, with species ovipositing into foam having smaller testes. No significant effects of clutch size or egg size were detected. In hylids, the relationship between testes mass and risk of sperm competition was positive but not significant, again with no predictable effects related to egg size or number. These data provide an important test of sperm competition theory for externally fertilizing taxa.     

Consideration of the order Cryptonemiales and the families Nemastomataceae and Furcellariaceae (Gigartinales,Rhodophyta) in light of the morphology of Adelophyton corneum (J. Agardh) gen. et comb. nov. from southern Australia

A new red algal genus is described, based on the southern Australian Chaetangium corneum J. Agardh. It is reproductively unique in that while the auxiliary cell is intercalary in an adventitious filament, a defining character of the order Cryptonemiales, the vegetative structure, carpogonial branches, connecting filaments and gonimoblast development seem strongly allied to lower families of the Gigartinales. Although its predominantly thallus-inward gonimoblast development is characteristic of the gigartinalian family Furcellariaceae, it is suggested that the new alga should be placed in the Nemastomataceae and that this family exhibits features which, in an ancient algal stock, could theoretically have given rise to the lower cryptonemialian and higher gigartinalian lines. The possible relationships between the Nemastomataceae, Furcellariaceae and Solieriaceae are discussed, and some seemingly primitive features of the Nemastomataceae are enumcrated.     

Protamine-like sperm nuclear basic proteins in the primitive frog Ascaphus truei and histone reversions among more advanced frogs

Sperm nuclear basic proteins (SNBPs) that condense chromatin are very diverse. In animals, evolution of SNBPs has proceeded from lysine-rich histone H type in sponges to more arginine-rich protamine-like PL and protamine P types. Yet sporadic PL/P to H reversions are known to occur in both protostomes and deuterostomes. To determine why this is the case, we have examined SNBPs in eleven anuran species. We find that sperm of the primitive, internally fertilizing archeobatrachian frog A. truei (family Ascaphidae) has PL/P type (42 mol % arginine), with an electrophoretic profile similar to SNBPs in another archeobatrachian, externally fertilizing Leiopelma hochstetteri (family Leiopelmatidae). Cytochemistry of sperm nuclei in the advanced, externally fertilizing neobatrachian frogs Crinia signifera and C. deserticola (family Myobatrachidae) indicates that they have reverted to H type SNBPs. This is also known to be the case in externally fertilizing Rana (family Ranidae) and Silurana, a subgenus of Xenopus (family Pipidae). Such a trend, from PL/P type SNBPs in two archeobatrachians to sporadic reversions to H type in more advanced frogs, parallels the ultrastructural simplification from complex A. truei introsperm to neobatrachian aquasperm that Jamieson et al. (1993. Herpetologica 49:52-65) attribute as a secondary reversion to external fertilization.     

DESCRIPTION OF A NEW DOLPHIN, THE AUSTRALIAN SNUBFIN DOLPHIN ORCAELLA HEINSOHNI SP. N. (CETACEA, DELPHINIDAE)

Comparisons of the Irrawaddy dolphin, Orcaella brevirostris , between Australian and Asian sites documented geographic differences in height of dorsal fin, presence or absence of a median dorsal groove in front of the dorsal fin, and coloration (presence or absence of a dorsal cape). Analysis of genetic data provided support for two clades within the Asian samples, the Mekong River samples from Cambodia and southern Laos, and all other marine and freshwater sites from Thailand, Indonesia, and the Philippines. The major separation, however, was between sites in Asia and those from Australia (5.9% of base pair differences, compared with 1.2% for within Australia and 1.5% for within Asia). Within a 403 base segment of the mtDNA control region, Australian specimens had 17 diagnostic sites with 16 fixed base pair differences and one insertion/deletion. Consistent, statistically significant differences in skull characters of Australian specimens have previously been demonstrated and are reviewed in this paper. There was a high concordance in character differences demonstrated between O. brevirostris from all Asian sites and Australian specimens, especially in the genetic and osteological characters. Based on the range and concordance of character differences, we propose that the Australian dolphins be recognized as a new species, Orcaella heinsohni (suggested common name: Australian snubfin dolphin).     

Notes on the diversity and distribution of Australian Naididae and Phreodrilidae (Oligochaeta: Annelida)

This paper provides a summary of the diversity and distribution of Australian naidid and phreodrilid oligochaetes. As for other continents, the Australian naidid fauna consists mostly of cosmopolitan species, although there are indications of greater endemicity than currently recognised. While some naidids are widespread in Australia, others have a northern or a southern bias to their distribution, but few have been recorded in Tasmania. Many new records and species of Phreodrilidae have been documented since the review by Pinder & Brinkhurst (1997a) and these have allowed notions of phreodrilid zoogeography to be refined. The family is still considered particularly diverse in some temperate areas (Tasmania and the far south-west of Western Australia), but surprisingly few species are known from the temperate south-east mainland. Increasingly, new phreodrilid species are being collected from seasonal habitats on granite outcrops in the south-west and from refugial habitats (caves, groundwater and permanent river pools) in drier regions. A complete picture of oligochaete distributions will require much more work and patterns suggested by current data are presented here as hypotheses.     

Avian louse phylogeny (Phthiraptera: Ischnocera): a cladistic study based on morphology

The louse suborder Ischnocera (Phthiraptera) contains 3060 currently described species from over 150 genera. These lice are permanent obligatory ectoparasites of a diverse selection of birds and mammals with a worldwide distribution. Historically, they have played a major role in the development of our ideas on coevolution, and species hosted by mammals have been used extensively as model organisms for the study of cospeciation. In contrast, avian taxa comprising 90% of ischnoceran species have been neglected due to a lack of data on their wider systematics. A comparative study based on the adult and nymphal instar morphology of avian lice yielded 138 characters from 56 species (51 genera), all of which are illustrated or discussed here for the first time. A further five outgroup taxa were examined from the mammalian ischnoceran family Trichodectidae. Phylogenetic analyses of these data produced three most parsimonious cladograms, the strict consensus of which is highly resolved and broadly consistent with previous classifications. Morphological character variation is extensive, and nymphal character traits are useful in identifying instances of convergent evolution in adult morphology. The role of ontogeny in the development of the major character complexes of the head and abdomen is discussed, and its implications for further work on the phylogeny of avian Ischnocera is considered. Comparison with host taxonomy reveals a series of complex host-parasite associations that do not support a hypothesis of strict one to one cospeciation. However, extrapolation of these associations is compromised by the low sample size. The role of niche specialization to explain the presence of multiple unrelated lineages on the same host taxon is considered.     

Comparative analysis of cutaneous evaporative water loss in frogs demonstrates correlation with ecological habits

Most frog species show little resistance to evaporative water loss (EWL), but some arboreal species are known to have very high resistances. We measured EWL and cutaneous resistance to evaporation (Rc) in 25 species of frogs from northern Australia, including 17 species in the family Hylidae, six species in the Myobatrachidae, and one each in the Bufonidae and the Microhylidae. These species display a variety of ecological habits, including aquatic, terrestrial, and arboreal specialisations, with the complete range of habits displayed within just the one hylid genus, Litoria. The 25 species measured in this study have resistances that range from Rc=0 to 63.1. These include low values indistinguishable from a free water surface to high values typical of "waterproof" anuran species. There was a strong correlation between ecological habit and Rc, even taking phylogenetic relationships into account; arboreal species had the highest resistance, aquatic species tended to have little or no resistance, and terrestrial species tended to have resistance between those of arboreal and aquatic frogs. For one species, Litoria rubella, we found no significant changes in EWL along a 1,500-km aridity gradient. This study represents the strongest evidence to date of a link between ecological habits and cutaneous resistance to water loss among species of frogs.     

The genus Archidendron (Leguminosae – Mimosoideae)

An account is given of the morphology and the taxonomy of the Asian, Australian and Pacific genus Archidendron (Leguminosae – Mimosoideae). A new infrageneric classification based on morphological data is presented, the genus being subdivided in 8 series. The phylogeny of the genus is discussed, the base of discussion being all available morphological, palynological and wood–anatomical characters. The presence/absence of stipules, the length of the staminal tube compared with that of the corolla–tube, the sessile/stipitate ovary(–ies), the morphology of the pods and the wood–anatomy have been particularly useful in determining the evolutionary trends within the genus. Analyses of the geographical range of selected character states are presented. The data suggest a Central – W. Malesian origin of the genus. The series endemic to the E. Malesian – Australian area have probably evolved more recently. The pluricarpellate condition of the flowers in several species endemic to the E. Malesian and Australian area is considered to be a derived character state. The following new taxa are proposed: Ser. Calycinae Nielsen, ser. Ptenopae Nielsen, ser. Bellae Nielsen, Archidendron falcatum Nielsen, A. cockburnii Nielsen, A. sabahense Nielsen, A. fagifolium (Bl. ex Miq.) Nielsen var. borneense Nielsen, A. kunsrteri (Prain) Nielsen subsp. ashtonii Nielsen, A. ellipticum (Bl.) Nielsen subsp. cordifoliolatum Nielsen. New combinations are proposed in the Malesian species formerly referred to Abarema, Zygia and Morolobium by Kostermans. Keys to and an enumeration of the species are presented.     

The genus Archidendron (Leguminosae - Mimosoideae)

An account is given of the morphology and the taxonomy of the Asian, Australian and Pacific genus Archidendron (Leguminosae - Mimosoideae). A new infrageneric classification based on morphological data is presented, the genus being subdivided in 8 series. The phylogeny of the genus is discussed, the base of discussion being all available morphological, palynological and wood-anatomical characters. The presence/absence of stipules, the length of the staminal tube compared with that of the corolla-tube, the sessile/stipitate ovary(-ies), the morphology of the pods and the wood-anatomy have been particularly useful in determining the evolutionary trends within the genus. Analyses of the geographical range of selected character states are presented. The data suggest a Central - W. Malesian origin of the genus. The series endemic to the E. Malesian - Australian area have probably evolved more recently. The pluricarpellate condition of the flowers in several species endemic to the E. Malesian and Australian area is considered to be a derived character state. The following new taxa are proposed: Ser. Calycinae Nielsen, ser. Ptenopae Nielsen, ser. Bellae Nielsen, Archidendron falcatum Nielsen, A. cockburnii Nielsen, A. sabahense Nielsen, A. fagifolium (Bl. ex Miq.) Nielsen var. borneense Nielsen, A. kunstleri (Prain) Nielsen subsp. ashtonii Nielsen, A. ellipticum (Bl.) Nielsen subsp. cordifoliolatum Nielsen. New combinations are proposed in the Malesian species formerly referred to Abarema, Zygia and Morolobium by Kostermans. Keys to and an enumeration of the species are presented.     

Molecular phylogenetic evidence for paraphyly of the genus Sooglossus, with the description of a new genus of Seychellean frogs

The Seychelles harbour an endemic frog family, the Sooglossidae, currently containing two genera: Sooglossus , with three species, and Nesomantis , with one species. These unique frogs are generally considered to be basal neobatrachians, although their relationships to other neobatrachian taxa, except the Nasikabatrachidae, remain unresolved. Our molecular phylogeny based on a dataset consisting of fragments of the nuclear rag-1 and rag-2 genes, as well as mitochondrial 16S rRNA in representatives of the major neobatrachian lineages, confirmed the previously postulated Sooglossidae + Nasikabatrachidae clade and the placement of the South American Caudiverbera with the Australian Myobatrachidae, but did not further resolve the position of sooglossids. Our results do, however, unambiguously show sooglossids to be monophyletic but the genus Sooglossus to be paraphyletic, with the type species Sooglossus sechellensis being more closely related to Nesomantis thomasseti than to Sooglossus gardineri and Sooglossus pipilodryas , in agreement with morphological, karyological, and bioacoustic data. As a taxonomic consequence, we propose to consider the genus name Nesomantis as junior synonym of Sooglossus , and to transfer the species thomasseti to Sooglossus . For the clade composed of the species gardineri and pipilodryas , here, we propose the new generic name Leptosooglossus . A significant genetic differentiation of 3% was found between specimens of Sooglossus thomasseti from the Mahé and Silhouette Islands, highlighting the need for further studies on their possible taxonomic distinctness.   © 2007 The Linnean Society of London, Biological Journal of the Linnean Society , 2007, 91 , 347–359.     

Biogeography of Eocene bryozoans from the St Vincent Basin, South Australia

The first extensive and stratigraphically detailed taxonomic study of the Middle to Late Eocene Bryozoa of the St Vincent Basin has identified more than 200 species of Cheilostomata and 50 species of Cyclostomata. There are three biogeographic groups: basin endemic, Australian and global. Two-thirds (116) of the cheilostome species and seven genera are currently considered endemic to this basin. Most species are endemic to Australia and similar to those found in the Oligo-Miocene of Victoria. The Cellariidae are a common component of most Australian Cainozoic deposits, but the species are highly dissimilar, with 13 of the 17 species here being new. The global component indicates that biogeographic links with regions outside Australia still existed in the Eocene. The cyclostome genus Reticrescis is only known from the Australian and Antarctic Eocene. Ten genera have their first occurrence in the Eocene St Vincent Basin. The Phidoloporidae and Smittinidae represent the most diverse and ubiquitous groups at a geological time close to their time of origination. Contemporaneous sediments in Antarctica, eastern Europe and North America also have a diverse fauna of this family, pointing to a strong Tethyan link. Rhamphosmittina lateralis (MacGillivray) is still extant in New Zealand, having an exceptionally long time range of 40 million years. Overall, the fauna has a distinct Late Cretaceous character. A new genus of Onychocellidae appears similar to genera that were common in Cretaceous Tethyan faunas but rare during the Cainozoic. This similarity ends in the Oligocene, after which the Australian bryozoan became endemic     

Interconnections between apoptotic,autophagic and necrotic pathways: implications for cancer therapy development

The rapid accumulation of knowledge on apoptosis regulation in the 1990s was followed by the development of several experimental anticancer‐ and anti‐ischaemia (stroke or myocardial infarction) drugs. Activation of apoptotic pathways or the removal of cellular apoptotic inhibitors has been suggested to aid cancer therapy and the inhibition of apoptosis was thought to limit ischaemia‐induced damage. However, initial clinical studies on apoptosis‐modulating drugs led to unexpected results in different clinical conditions and this may have been due to co‐effects on non‐apoptotic interconnected cell death mechanisms and the ‘yin‐yang’ role of autophagy in survival versus cell death. In this review, we extend the analysis of cell death beyond apoptosis. Upon introduction of molecular pathways governing autophagy and necrosis (also called necroptosis or programmed necrosis), we focus on the interconnected character of cell death signals and on the shared cell death processes involving mitochondria (e.g. mitophagy and mitoptosis) and molecular signals playing prominent roles in multiple pathways (e.g. Bcl2‐family members and p53). We also briefly highlight stress‐induced cell senescence that plays a role not only in organismal ageing but also offers the development of novel anticancer strategies. Finally, we briefly illustrate the interconnected character of cell death forms in clinical settings while discussing irradiation‐induced mitotic catastrophe. The signalling pathways are discussed in their relation to cancer biology and treatment approaches.     

Diversification of New Zealand weta (Orthoptera: Ensifera: Anostostomatidae) and their relationships in Australasia

New Zealand taxa from the Orthopteran family Anostostomatidae have been shown to consist of three broad groups, Hemiandrus (ground weta), Anisoura/Motuweta (tusked weta) and Hemideina-Deinacrida (tree-giant weta). The family is also present in Australia and New Caledonia, the nearest large land masses to New Zealand. All genera are endemic to their respective countries except Hemiandrus that occurs in New Zealand and Australia. We used nuclear and mitochondrial DNA sequence data to study within genera and among species-level genetic diversity within New Zealand and to examine phylogenetic relationships of taxa in Australasia. We found the Anostostomatidae to be monophyletic within Ensifera, and justifiably distinguished from the Stenopelmatidae among which they were formerly placed. However, the New Zealand Anostostomatidae are not monophyletic with respect to Australian and New Caledonian species in our analyses. Two of the New Zealand groups have closer allies in Australia and one in New Caledonia. We carried out maximum-likelihood and Bayesian analyses to reveal several well supported subgroupings. Our analysis included the most extensive sampling to date of Hemiandrus species and indicate that Australian and New Zealand Hemiandrus are not monophyletic. We used molecular dating approaches to test the plausibility of alternative biogeographic hypotheses for the origin of the New Zealand anostostomatid fauna and found support for divergence of the main clades at, or shortly after, Gondwanan break-up, and dispersal across the Tasman much more recently.     

The evolutionary relations of sunken, covered, and encrypted stomata to dry habitats in Proteaceae

Sunken, covered, and encrypted stomata have been anecdotally linked with dry climates and reduced transpiration and therefore have been used to infer dry palaeoclimates from fossils. This study assesses the evolutionary and ecological associations of such stomatal protection in a model system-the diverse southern hemisphere family Proteaceae. Analyses were based on the morphology of over 1400 Australian, South African, New Caledonian, New Zealand, and South American species, anatomy of over 300 of these species, and bioclimatic data from all 1109 Australian species. Ancestral state reconstruction revealed that five or six evolutionary transitions explain over 98% of the dry climate species in the family, with a few other, minor invasions of dry climates. Deep encryption, i.e., stomata in deep pits, in grooves, enclosed by tightly revolute margins or strongly overarched by cuticle, evolved at least 11 times in very dry environments. Other forms of stomatal protection (sunken but not closely encrypted stomata, papillae, and layers of hairs covering the stomata) also evolved repeatedly, but had no systematic association with dry climates. These data are evidence for a strong distinction in function, with deep encryption being an adaptation to aridity, whereas broad pits and covered stomata have more complex relations to climate.     

Dollo's law and the re-evolution of shell coiling

Gastropods have lost the quintessential snail feature, the coiled shell, numerous times in evolution. In many cases these animals have developed a limpet morphology with a cap-shaped shell and a large foot. Limpets thrive in marginal habitats such as hydrothermal vents, the high-energy rocky intertidal areas and fresh water, but they are considered to be evolutionary dead-ends, unable to re-evolve a coiled shell and therefore unable to give rise to the diversity seen among coiled snails. The re-evolution of a coiled shell, or any complex character, is considered unlikely or impossible (Dollo's law) because the loss of the character is followed by the loss of the genetic architecture and developmental mechanisms that underlie that character. Here, we quantify the level of coiling in calyptraeids, a family of mostly uncoiled limpets, and show that coiled shells have re-evolved at least once within this family. These results are the first demonstration, to our knowledge, of the re-evolution of coiling in a gastropod, and show that the developmental features underlying coiling have not been lost during 20-100 Myr of uncoiled evolutionary history. This is the first example of the re-evolution of a complex character via a change in developmental timing (heterochrony) rather than a change in location of gene expression (heterotopy).