Southern Hemisphere Family Research Articles

An account of the Cunoniaceae in the Solomon archipelago and Vanuatu

SummaryFive genera of the largely southern hemisphere family Cunoniaceae occur in the Solomon archipelago (Solomon Islands plus the Autonomous Region of Bougainville, Papua New Guinea): Geissois, Pterophylla (previously Weinmannia p.p.), Spiraeanthemum, Schizomeria and Ackama (including Spiraeopsis) (total of 12 species); the first three genera are also found in Vanuatu (total of four species). None of the genera is endemic to these two archipelagos although more than half the species are and Spiraeanthemum macgillivrayi Seem. is the only species common to both island groups. Along with keys to the genera and species, accounts are given for G. denhamii Seem. (throughout Vanuatu), G. pentaphylla C.T.White (restricted to the island of Vanikoro, Solomon Islands), and P. makiniae H.C.Hopkins, J.Bradford & Pillon sp. nov., from Vangunu and Kolombangara in the Solomon Islands. Most of the remaining taxa have been revised for generic treatments or flora accounts and for these, only a synopsis is given with notes on types for some names. Provisional conservation assessments are provided, with ecological summaries. Generic diversity in the Cunoniaceae decreases eastwards across the Pacific Ocean to the Marquesas and Austral Islands. The islands in the western Pacific have surprisingly few genera in common with Australia, and, compared with New Caledonia, Fiji or the Solomon archipelago, Vanuatu has fewer taxa than might be predicted from its location and size, presumably because of its young geological age.

Cherax latimanus sp. nov., a new burrow-dwelling freshwater crayfish (Decapoda, Parastacidae) from the mid-Murray River catchment, Australia.

A new species of freshwater crayfish in the southern hemisphere family Parastacidae is described from the Murray Darling Basin (MDB), eastern Australia. The Swamp Yabby, Cherax latimanus sp. nov., is found in the mid-Murray River area of the states of New South Wales and Victoria and is only the third species of Cherax found naturally occurring in the MDB. It is morphologically distinguished from all other species of Cherax by the presence of marginal mesial dactylar basal spines and extensive ventral propodal setation. It is found in sympatry with the widespread but morphologically similar Common Yabby, Cherax destructor Clark, 1936, but can be distinguished by a suite of morphometric and meristic characters that include a broad rostrum lacking an apical spine, very broad chelae with deep punctations on the lateral propodal edge and ventral propodal setation, two prominent dactylar teeth, one mesial carpal spine, dorsal meral spines present, no setae on carpal mesial margin, cervical spines absent or tiny, and by genetic data. Cherax latimanus is further diagnosed by its distinctive biology: it is not found in permanent aquatic habitats such as streams or billabongs, spending the majority of its time in extensive, terrestrial, burrow networks containing some water, in ephemerally wet habitats such as drainage lines, roadside drains, depressions, swamps and cleared areas of pasture in lowland to foothill areas. It is occasionally found in stream habitats but only during large flood events when burrow systems are inundated.

Genome skimming-based simple sequence repeat (SSR) marker discovery and characterization in Grevillea robusta.

Proteaceae, a largely southern hemisphere family consisting of 80 genera distributed in Australia and southern Africa as its centres of greatest diversity, also extends well in northern and southern America. Under this family, Grevillea robusta is a fast-growing species got popularity in farm and avenue plantations. Despite the ecological and economic importance, the species has not yet been investigated for its genetic improvement and genome-based studies. Only a few molecular markers are available for the species or its close relatives, which hinders genomic and population genetics studies. Genetic markers have been intensively applied for the main strategies in breeding programs, especially for the economically important traits. Hence, it is of utmost priority to develop genomic database resources and species-specific markers for studying quantitative genetics in G. robusta. Given this, the present study aimed to develop de novo genome sequencing, robust microsatellites markers, sequence annotation and their validation in different stands of G. robusta in northern India. Library preparation and sequencing were carried out using Illumina paired-end sequencing technology. Approximately, ten gigabases (Gb) sequence data with 70.87 million raw reads assembled into 425,923 contigs (read mapped to 76.48%) comprising 455 Mb genome size (23 × coverage) generated through genome skimming approach. In total, 9421 simple sequence repeat (SSR) primer pairs were successfully designed from 13,335 microsatellite repeats. Afterward, a subset of 161 primer pairs was randomly selected, synthesized and validated. All the tested primers showed successful amplification but only 13 showed polymorphisms. The polymorphic SSRs were further used to estimate the measures of genetic diversity in 12 genotypes each from the states of Punjab, Haryana, Himachal Pradesh and Uttarakhand. Importantly, the average number of alleles (Na), observed heterozygosity (Ho), expected heterozygosity (He), and the polymorphism information content (PIC) were recorded as 2.69, 0.356, 0.557 and 0.388, respectively. The availability of sequence information and newly developed SSR markers could potentially be used in various genetic analyses and improvements through molecular breeding strategies for G. robusta.Supplementary InformationThe online version contains supplementary material available at 10.1007/s12298-021-01035-w.

<p><strong>Fleas are parasitic scorpionflies</strong></p>

Fleas (Siphonaptera) are medically important blood-feeding insects responsible for spreading pathogens such as plague, murine typhus, and myxomatosis. The peculiar morphology of fleas resulting from their specialised ectoparasitic lifestyle has meant that the phylogenetic position of this diverse and medically important group has remained one of the most persistent problems in insect evolution. Here we test competing hypotheses on the contentious evolutionary relationships of fleas and antliophoran insects using the largest molecular dataset available to date consisting of over 1,400 protein-coding genes, and a smaller mitogenome and Sanger sequence alignment of 16 genes. By removing ambiguously aligned sequence regions and using site-heterogeneous models, we consistently recover fleas nested within scorpionflies (Mecoptera) as sister to the relictual southern hemisphere family Nannochoristidae. Topology tests accounting for compositional heterogeneity strongly favour the proposed topology over previous hypotheses of antliophoran relationships. This clade is diagnosed by shared morphological characters of the head and sperm pump. Fleas may no longer be regarded as a separate insect order and we propose that Siphonaptera should be treated as an infraorder within Mecoptera, reducing the number of extant holometabolan insect orders to ten.

Dichromatobolus, a new genus of spirobolidan millipedes from Madagascar (Spirobolida, Pachybolidae)

A new genus, Dichromatobolus gen. nov., belonging to the genus-rich mainly southern hemisphere family Pachybolidae of the order Spirobolida, is described based on D. elephantulus gen. et sp. nov., illustrated with color pictures, line drawings, and scanning electron micrographs. The species is recorded from the spiny bush of southwestern Madagascar. Dichromatobolus elephantulus gen. et sp. nov. shows an unusual color pattern, sexual dichromatism with males being red with black legs and females being grey. Males seem to be more surface active, as mainly males were collected with pitfall traps. Females mainly come from the pet trade. The body of this species is short and very wide, being only 8 times longer than wide in the males. Live observations show the species is a very slow mover, digging in loose soil almost as fast as walking on the surface. The posterior gonopods of Dichromatobolus gen. nov. are unusually simple and well-rounded, displaying some similarities to the genera Corallobolus Wesener, 2009 and Granitobolus Wesener, 2009, from which the new genus differs in numerous other characters, e.g., size, anterior gonopods and habitus. Despite several attempts with fresh tissue samples and different primers, molecular barcoding did not work for Dichromatobolus gen. nov. Any relationships to the other 15 genera of Pachybolidae indigenous to Madagascar remain unknown.

A Review of Galaxias (Galaxiidae) Fossils from the Southern Hemisphere

The Galaxiidae is a Southern Hemisphere family of freshwater fish, considered to be of Gondwanan origin based on the current distribution of species in New Zealand, Australia (including Tasmania), New Caledonia, Africa, South America, and on some associated and subantarctic islands. The fossil record of galaxiids is extremely sparse and geographically restricted. The only galaxiid fossils currently known come from several Miocene lakes in southern New Zealand. They include more than 100 articulated fishes, some remarkably preserving soft parts such as eyes and skin, skulls and jaw components, and more than 200 isolated otoliths. Common coprolites and in situ preserved gut content at one site (Foulden Maar) indicate the different diets of larvae and adult fish. These discoveries reveal a diverse Galaxias fauna, the presence of lake-locked populations, ontogenetic diet shifts, and representatives of several non-migratory Galaxias lineages associated with inland streams and lakes. There are at least six Galaxias species based on macrofossils and six separate otolith-based species from varied volcanic and regional lacustrine environments. This diversity points to southern New Zealand as a centre of biodiversity and speciation in Galaxiidae in the early to late Miocene.

Links between environment and stomatal size through evolutionary time in Proteaceae.

The size of plant stomata (adjustable pores that determine the uptake of CO2 and loss of water from leaves) is considered to be evolutionarily important. This study uses fossils from the major Southern Hemisphere family Proteaceae to test whether stomatal cell size responded to Cenozoic climate change. We measured the length and abundance of guard cells (the cells forming stomata), the area of epidermal pavement cells, stomatal index and maximum stomatal conductance from a comprehensive sample of fossil cuticles of Proteaceae, and extracted published estimates of past temperature and atmospheric CO2. We developed a novel test based on stochastic modelling of trait evolution to test correlations among traits. Guard cell length increased, and stomatal density decreased significantly with decreasing palaeotemperature. However, contrary to expectations, stomata tended to be smaller and more densely packed at higher atmospheric CO2. Thus, associations between stomatal traits and palaeoclimate over the last 70 million years in Proteaceae suggest that stomatal size is significantly affected by environmental factors other than atmospheric CO2. Guard cell length, pavement cell area, stomatal density and stomatal index covaried in ways consistent with coordinated development of leaf tissues.

Fossil evidence for the evolution of the Casuarinaceae in response to low soil nutrients and a drying climate in Cenozoic Australia

The Southern Hemisphere family Casuarinaceae has a long fossil record, both macrofossils and pollen, none of which provides any evidence about the morphology of the precursor to the family. However, it has long been considered, from both molecular phylogenies and morphological data, that the extant genus Gymnostoma retains key ancestral states and the highly reduced leaf area is a result of a scleromorphic response to low soil nutrients. Gymnostoma has by far the earliest, most extensive and best preserved macrofossil record, beginning in the Late Paleocene. Modification of the stomatal location from superficial in Gymnostoma to encrypted in furrows in the other genera assisted in water conservation as species evolved. We conclude that the morphology of the living and fossil vegetative branchlets provides evidence that low soil nutrients (especially phosphorus) and high water availability in a relatively light limited environment were the original drivers for evolution in the Casuarinaceae. Reducing water availability (xeromorphy) in progressively higher light environments were the major drivers of post-Eocene evolution in this unique plant family.

Dispariflora robertae gen. et sp. nov., a mid-Cretaceous flower of possible Lauralean affinity from Myanmar amber

Three flowers of a fossil angiosperm preserved in amber from Myanmar (Burma) are described as the new genus and species Dispariflora robertae. Although joined in a single cymose inflorescence, the flowers are variable in size and, in addition, they possess an unusual perianth in which 1 sepal is much enlarged and leaf-like, while the remaining 4 are smaller and unequal. The flowers each have 1 superior pistil with a peculiarly plumose and bristly ovary. The number of stamens is uncertain because most were lost before floral preservation, but scars on the receptacle suggest that at least 15 were present. The bithecal anthers open by longitudinal slits and basal glands may have been present on the filaments. Taken as a whole, the floral features that characterize Dispariflora suggest an affinity with members of Laurales, especially several Southern Hemisphere families allied with the Monimiaceae.

To sea or not to sea? Multiple lines of evidence reveal the contribution of non‐diadromous recruitment for supporting endemic fish populations within New Zealand's longest river

Abstract Otolith microchemistry was used to identify marine‐ versus freshwater‐derived recruitment of three native freshwater fish species belonging to the southern hemisphere family Galaxiidae, in New Zealand's longest river system, the Waikato River. Water chemistry data for trace elements and 87Sr/86Sr isotope ratios were collected from five lentic and 10 lotic water bodies throughout the lower river floodplain. Potential spawning sites for galaxiids were compared with values obtained by laser ablation inductively coupled mass spectrometry (LA‐ICPMS) depth profiling of young‐of‐the‐year otoliths sampled from fish in nine lower river catchment sites. Otolith chemical signatures from the larval rearing period indicated that catchment‐scale recruitment for two species, Galaxias argenteus (Gmelin, 1789) and Galaxias fasciatus Gray, 1842, was driven predominantly by non‐diadromous recruitment from one lake (Lake Waahi). In contrast, diadromous recruitment appeared to be more common for Galaxias maculatus (Jenyns, 1842); however, non‐diadromous specimens were also identified for the first time from a New Zealand river. Reversing lake outlet flows linked to river stage appears be important in facilitating the dispersal of rheotactic larvae out of lakes, suggesting that lake outflow management at key times could be used to sustain this ecologically important function. This study highlights that some water bodies can supply a disproportionately large number of recruits to support fish populations within the wider riverscape. Identifying these water bodies and managing them to sustain recruitment is key to the conservation of non‐diadromous Galaxiidae in this modified lowland environment

Cellular ion interactions in two endemic tropical rainforest species of a novel metallophytic tree genus.

Gossia, a small genus of physiologically novel rainforest trees restricted to the Western Pacific and belonging to a key neotropical Southern Hemisphere family, the Myrtaceae, is characterized by high foliar manganese (Mn) concentrations. This field study provides a quantitative in planta snapshot detailing cellular localization of foliar Mn and other mineral nutrients in sympatric Gossia grayi N. Snow & Guymer and Gossia shepherdii N. Snow & Guymer endemic to far northeastern Australia, and previously not examined. Elements localized in the cells of fresh hydrated leaf tissues were quantified via in vivo cryo-scanning electron microscopy energy dispersive spectroscopy, a non-invasive method that effectively immobilizes cell contents. Leaf anatomical differences were found between species, along with foliar Mn spatial distribution patterns. Localized cellular Mn concentrations exceeding 600 mmol kg-1 were detected in G. shepherdii, whose Mn accumulation across different mesophyll cell types was heterogeneous compared with G. grayi. In both species there was little evidence to support previous findings on other Gossia species of carboxylate association with excess Mn. The analytical X-ray data strongly implicated chloride as a counter-ion to Mn in the two species examined here. The key findings align with the hypothesis that Mn disposal in the mesophyll is a generic trait in Gossia. This research has forged an emerging view of Gossia as being characterized by unusual cellular metal and mineral accumulation patterns that vary at the species level. It contributes to current limited knowledge about generic plant metallophyty, highlighting that assimilating a broader perspective of the phenomenon demands evaluation of individual taxa through field studies.

Phylotranscriptomics resolves ancient divergences in the Lepidoptera

AbstractClassic morphological studies of the oldest, so‐called nonditrysian lineages of Lepidoptera yielded a well‐resolved phylogeny, supported by the stepwise origin of the traits characterizing the clade Ditrysia, which contains over 98% of extant lepidopterans. Subsequent polymerase chain reaction (PCR)‐based molecular studies have robustly supported many aspects of the morphological hypothesis and strongly contradicted others, while leaving some relationships unsettled. Here we bring the greatly expanded gene sampling of RNA‐Seq to bear on nonditrysian phylogeny, especially those aspects that were not conclusively resolved by the combination of morphology and previous PCR‐based multi‐gene studies. We analysed up to 2212 genes in each of 28 species representing all 12 superfamilies and 15 of 21 families of nonditrysians, plus trichopteran outgroups and representative Ditrysia. Our maximum likelihood phylogeny estimates used both nonsynonymous changes only (degen1 coding) and all nucleotides (nt123) partitioned by codon position, recovering a novel hypothesis for early glossatan relationships that is the most strongly supported to date. We find strong support for Micropterigidae alone as the sister group to all other Lepidoptera, in agreement with morphology and early molecular evidence, but in contrast to recent PCR‐based studies. Also very strongly supported are the previously recognized clades Angiospermivora, Heteroneura, Eulepidoptera and Euheteroneura. Finally, we find strong support for paraphyly of the southern hemisphere family Palaephatidae, with the South American genus Palaephatus Butler forming the previously undetermined sister group to Ditrysia. The remaining palaephatids, Australian and South American, form the sister group to Tischeriidae.

Year-round growing conditions explains large CO2 sink strength in a New Zealand raised peat bog

Abstract We measured net ecosystem CO2 exchange (NEE) for two years in a remnant New Zealand raised peat bog using the eddy covariance technique and estimated the component CO2 fluxes gross primary production (GPP) and ecosystem respiration (ER). Vegetation was dominated by vascular plants belonging to the southern hemisphere family Restionaceae, comprising an overstory of the erect Sporadanthus ferrugineus and a dense understory of Empodisma robustum. Annual NEE (GPP, ER) totals for the two years were −218.2 (1124.2, 906.0) gC m−2 yr−1 and −250.3 (1148.3, 897.8) gC m−2 yr−1, indicating substantially larger CO2 sink strength than has been reported for peatland ecosystems in the northern hemisphere. The bog was a net sink for CO2 in nine months each year, with small differences in autumn and wintertime NEE accounting for most of the difference in annual NEE totals. Summer daytime average NEE were similar to published values for northern hemisphere peatlands, despite differences in vegetation type and a comparatively deep water table. Fitted ecosystem light response and respiration model parameters were also within the ranges of values reported for peatlands elsewhere. The major distinction compared to northern peatlands was the year-round productivity of the evergreen vegetation cover in New Zealand, which largely offset respiration losses during the short, mild winter season.

Integrated shotgun sequencing and bioinformatics pipeline allows ultra-fast mitogenome recovery and confirms substantial gene rearrangements in Australian freshwater crayfishes

BackgroundAlthough it is possible to recover the complete mitogenome directly from shotgun sequencing data, currently reported methods and pipelines are still relatively time consuming and costly. Using a sample of the Australian freshwater crayfish Engaeus lengana, we demonstrate that it is possible to achieve three-day turnaround time (four hours hands-on time) from tissue sample to NCBI-ready submission file through the integration of MiSeq sequencing platform, Nextera sample preparation protocol, MITObim assembly algorithm and MITOS annotation pipeline.ResultsThe complete mitochondrial genome of the parastacid freshwater crayfish, Engaeus lengana, was recovered by modest shotgun sequencing (1.2 giga bases) using the Illumina MiSeq benchtop sequencing platform. Genome assembly using the MITObim mitogenome assembler recovered the mitochondrial genome as a single contig with a 97-fold mean coverage (min. = 17; max. = 138). The mitogenome consists of 15,934 base pairs and contains the typical 37 mitochondrial genes and a non-coding AT-rich region. The genome arrangement is similar to the only other published parastacid mitogenome from the Australian genus Cherax.ConclusionsWe infer that the gene order arrangement found in Cherax destructor is common to Australian crayfish and may be a derived feature of the southern hemisphere family Parastacidae. Further, we report to our knowledge, the simplest and fastest protocol for the recovery and assembly of complete mitochondrial genomes using the MiSeq benchtop sequencer.

From East Gondwana to Central America: historical biogeography of the Alstroemeriaceae

AbstractAim The Alstroemeriaceae is among 28 angiosperm families shared between South America, New Zealand and/or Australia; here, we examine the biogeography of Alstroemeriaceae to better understand the climatic and geological settings for its diversification in the Neotropics. We also compare Alstroemeriaceae with the four other Southern Hemisphere families that expanded from Patagonia to the equator, to infer what factors may have permitted such expansions across biomes.Location South America, Central America, Australia and New Zealand.Methods Three chloroplast genes, one mitochondrial gene and one nuclear DNA region were sequenced for 153 accessions representing 125 of the 200 species of Alstroemeriaceae from throughout the distribution range; 25 outgroup taxa were included to securely infer evolutionary directions and be able to use both ingroup and outgroup fossil constraints. A relaxed‐clock model relied on up to three fossil calibrations, and ancestral ranges were inferred using statistical dispersal–vicariance analysis (S‐DIVA). Southern Hemisphere disjunctions in the flowering plants were reviewed for key biological traits, divergence times, migration directions and habitats occupied.Results The obtained chronogram and ancestral area reconstruction imply that the most recent common ancestor of Colchicaceae and Alstroemeriaceae lived in the Late Cretaceous in southern South America/Australasia, the ancestral region of Alstroemeriaceae may have been South America/Antarctica, and a single New Zealand species is due to recent dispersal from South America. Chilean Alstroemeria diversified with the uplift of the Patagonian Andes c. 18 Ma, and a hummingbird‐pollinated clade (Bomarea) reached the northern Andes at 11–13 Ma. The South American Arid Diagonal (SAAD), a belt of arid vegetation caused by the onset of the Andean rain shadow 14–15 Ma, isolated a Brazilian clade of Alstroemeria from a basal Chilean/Argentinean grade.Main conclusions Only Alstroemeriaceae, Calceolariaceae, Cunoniaceae, Escalloniaceae and Proteaceae have expanded and diversified from Patagonia far into tropical latitudes. All migrated northwards along the Andes, but also reached south‐eastern Brazil, in most cases after the origin of the SAAD. Our results from Alstroemeria now suggest that the SAAD may have been a major ecological barrier in southern South America.

New Late Cretaceous and Paleocene Dicot Woods of Big Bend National Park, Texas and Review of Cretacous Wood Characteristics

Three new wood types from the Late Cretaceous and one from the Paleocene of Big Bend National Park, Texas, U.S.A. add to our knowledge of North American Late Cretaceous and Paleocene plants. Sabinoxylon wicki sp. nov. provides further evidence of similarities in late Campanian-early Maastrichtian vegetation of Texas, New Mexico, and northern Mexico. This species is characterized by mostly solitary vessels, scalariform perforation plates, vessel-ray parenchyma pits similar to intervessel pits, vasicentric tracheids, and two size classes of rays. Storage tissue accounts for close to 50% of its wood volume. Another of the new Cretaceous wood types, referred to as Big Bend Ericalean Wood Type I, has more than 40% ray parenchyma. Both Big Bend Ericalean Wood Type I and Sabinoxylon have a combination of characters that occurs in the order Ericales (sensu APGII). The third new Cretaceous wood type is from a small axis (less than 3 cm diameter), and has a combination of features that is the most common pattern in extant eudicots (vessels solitary and in radial multiples randomly arranged, simple perforation plates and alternate intervessel pits, and heterocellular rays). The Paleocene wood (cf. Cunonioxylon sensu Gottwald) differs from all other North American Paleocene woods and has characteristics found in the predominantly Southern Hemisphere family Cunoniaceae. The characteristics of these new Big Bend woods contribute to a database for fossil angiosperm woods, and allow for comparison of incidences of selected wood anatomical features in Northern Hemisphere Cretaceous woods from Albian to Maastrichtian time as well as comparison with extant woods. Cretaceous woods as a whole differ from Recent woods in having higher incidences of exclusively solitary vessels, scalariform perforation plates, and wide rays (>10-seriate), and lower incidences of ring porosity, wide vessels (>200 μm), vessels in groups, non-random arrangements of vessels, and marginal parenchyma. The occurrence of relatively high percentages of storage cells (>40%) in some Cretaceous trees is noteworthy; the ability to produce wood with varying amounts and arrangements of parenchyma is likely to be a contributing factor to the success of angiosperm trees in a wide variety of environments.

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.

Galaxias fossils from Miocene lake deposits, Otago, New Zealand: The earliest records of the Southern Hemisphere family Galaxiidae (Teleostei)

Galaxiid fishes are commonly assumed to exhibit a Gondwanan distribution, but little fossil evidence has been available to support or refute this assumption until now. Here we report on three species of fossil Galaxias, represented by exquisitely preserved, almost entire skeletons, together with jaw and skull fragments, from several Miocene lacustrine deposits in Otago, South Island, New Zealand. These are the only certain Galaxias fossils, and provide unequivocal evidence that the genus was abundant, and taxonomically and ecologically diverse in the New Zealand region before 23 million years ago. One new species, Galaxias effusus, from an Early Miocene diatomite deposit near Middlemarch is described on the basis of low vertebral count, short caudal peduncle, expansive dorsal, caudal and anal fins, rounded to truncate caudal fin, with 15 principal caudal fin rays. The intact skeletons of G. effusus confirm that they inhabited a deep, stratified maar lake with cool, anoxic bottom water. The maar lake was completely landlocked, from sedimentological evidence, and this species must have been non‐migratory. Disarticulated fish jaws and skull fragments from Early Miocene mudstones near Bannockburn are likely to be from a second large species of Galaxias on the basis of dentary, premaxilla and parasphenoid size and morphology. These disarticulated fish remains from a regionally extensive inland lake system indicate decomposition and/or predation in shallow nearshore environments, but we have no evidence yet of migratory behaviour. New specimens of G. kaikorai Whitley from Late Miocene diatomite deposits near Dunedin confirm its morphological similarity to the living G. brevipinnis. The occurrence and diversity of galaxiids in lakes of early and Late Miocene age in southern New Zealand can be explained by either oceanic dispersal across the Southern Hemisphere at any time during the Cenozoic, relict Gondwanan distributions or, most likely, an ancient Gondwanan origin overprinted by Cenozoic dispersal.

Tests of Current Hypotheses of Mayfly (Ephemeroptera) Phylogeny Using Molecular (18s rDNA) Data

Partial 18s rDNA sequences from 22 exemplar mayfly species (Ephemeroptera) representing 20 families were analyzed to obtain a best phylogenetic tree for comparison to previous phylogenetic hypotheses. With respect to relationships among the three major groupings, our molecular data support the hypothesis that Pisciforma and Setisura comprise a monophyletic sister group to the Furcatergalia, rather than the hypothesis that Setisura and Furcatergalia comprise a monophyletic group stemming from the Pisciforma. Within Pisciforma, acceptable trees show that Baetidae separates at the base of the Pisciforma clade. The data suggest that Pisciforma is paraphyletic and do not support the grouping of all Southern hemisphere families as a monophyletic group. An evolutionary sequence favored by the data suggests a grouping of Siphlonuridae, Rallidentidae, Nesameletidae, and Ameletidae and a grouping of Oniscigastridae, Ameletopsidae, and Acanthametropodidae. The data support the monophyly of Setisura (Heptageniidae, Arthropleidae, Pseudironidae, Oligoneuriidae, Isonychiidae, and Coloburiscidae). Within Setisura, a bootstrap/jackknife test places the families Heptageniidae, Arthropleidae, and Pseudironidae in one clade at 100% frequency. Also supported are hypotheses that Pseudironidae is a sister group to a Heptageniidae–Arthropleidae group and that a sister relationship exists between the latter two families. Hypotheses that Pseudironidae separated from other Setisura families at an earlier stage and comprises a sister group to a Heptageniidae–Oligonuriidae lineage or that Pseudironidae should be moved out of Setisura are not supported.

Solar radiation as a factor in the evolution of scleromorphic leaf anatomy in Proteaceae

Species of the major Southern Hemisphere family, Proteaceae, have many scleromorphic anatomical structures in their leaves. Many of these structures (very thick cuticles and five anatomically distinct structures beneath the epidermis) are associated with the leaf surface exposed to direct light. These structures increase the path through which solar radiation must pass before reaching the mesophyll. In this study, such structures are proposed to protect the mesophyll from excess solar radiation, including photosynthetically active, ultraviolet, and possibly infrared radiation. Scleromorphic structures of the upper leaf surface and nonscleromorphic photoprotective structures (dense trichomes and papillae of the upper surface) occur almost exclusively in open vegetation. Open vegetation species of Proteaceae occur in oligotrophic and/or cold and/or dry places, where protection from light in excess of photosynthetic capacity and damage from ultraviolet light should be most important. Data from 123 species and a supertree constructed from available molecular phylogenies are used to show that the proposed photoprotective structures evolved many times within Proteaceae. In tests of correlated evolution, the proposed photoprotective structures are significantly associated with open vegetation, but not with dry habitats.