Pseudofoenus caledonicus, a new species of hyptiogastrine wasp (Hymenoptera: Gasteruptiidae) from New Caledonia

Abstract  Pseudofoenus caledonicus sp. nov. is described from New Caledonia, and is the second member of the Hyptiogastrinae recorded from these islands. This discovery points to a more diverse fauna of Hyptiogastrinae in the south-west Pacific, which also includes P. ritae (Cheesman), from New Caledonia and Vanuatu, P. extraneus (Turner) from Fiji, and a number of species from New Guinea and New Zealand. Although a revised phylogenetic analysis does not resolve the relationships of P. caledonicus , neither the two New Caledonian species nor the south-west Pacific fauna in general are likely to be monophyletic. This fauna is discussed in terms of its relationships with Pseudofoenus spp. from mainland Australia, and possible mechanisms that have given rise to the current distribution of species.     

Solving alpha‐diversity by morphological markers contributes to arranging the systematic status of a crayfish species complex (Crustacea,Decapoda)

Since innovative molecular approaches in phylogenetics solely based on small gene fragments have often generated widely complicated interpretations of crayfish diversity, we propose a geometric morphometric study integrated with previous molecular data to provide robust estimates of phylogeny and classification of the Austropotamobius pallipes complex, genetically divided into several species and subspecies. We discuss whether cephalothorax shape variation can show phylogenetic signals congruent to those derived from analyses of mitochondrial and nuclear markers. Our results support the hypothesis that carapace form is potentially informative in the reconstruction of crayfish phylogeny. In the phenetic analyses, populations collected within the Italian territory form different unexpected clusters, each involving distant populations of different genetic haplogroups, suggesting a within‐species convergence probably due to a series of local adaptations. The phylogenetic analysis performed using a neighbour‐joining algorithm showed interesting relationships amongst the studied populations. In particular, the geometric morphometric matrices showed a slight congruence with some genetic distances, allowing the discrimination of three major lineages: (1) Istran + Apennine group; (2) Arno group; (3) north‐western group. Finally, our observations support some molecular data with a lighter phylogenetic signal that do not suggest a strong separation of A. pallipes into clades and sub‐clades.     

Zonation, behaviour and morphology of the intertida coral-treader Hermatobates (Hemiptera: Hermatobatidae) in the south-exst Pacific

The coral-treaders (Hermatobatidae) are the only exclusively marine family of insects. Observations in the Cook Islands, Samoa, Tonga and Fiji show that the insects can be abundant on shores that provide rocks with cavities that remain air-filled during high tide. The zone of suitable habitats for the insects is restricted to a narrow ( c. 20 cm) vertical band roughly centred around Mean Low Water Neaps. Transplant experiments show that the insects are unable to survive above or below this zone. The insects emerge from their rocky crevices about an hour before low tide, swim on the water surface during low tide, and return to their crevices about an hour after the tide has turned. There are only four larval instars, which can be readily separated by their morphology. Electron microscope studies show that the insects are clothed in a layer of micro-hairs of unique design: a short tapering shaft tipped with a sphere. These micro-hairs may act as a plastron: their distribution corresponds precisely to the pattern of the silvery 'air-layer' seen when the insects are submerged, their spherical tips provide a regular array that could support an air-water interface, they occur at high densities (up to 3.5 times 10⁶ mm^-2), and the layer makes connection with the thoracic spiracles. Half the insects were able to survive submergence in recirculated seawater for 12 hours. The adults appear to swim further from shore than the larvae, and they were observed copulating in tidal pools.     

Expanding Southwest Pacific mitochondrial haplogroups P and Q

Modern humans have occupied New Guinea and the nearby Bismarck and Solomon archipelagos of Island Melanesia for at least 40,000 years. Previous mitochondrial DNA (mtDNA) studies indicated that two common lineages in this region, haplogroups P and Q, were particularly diverse, with the coalescence for P considered significantly older than that for Q. In this study, we expand the definition of haplogroup Q so that it includes three major branches, each separated by multiple mutational distinctions (Q1, equivalent to the earlier definition of Q, plus Q2 and Q3). We report three whole-mtDNA genomes that establish Q2 as a major Q branch. In addition, we describe 314 control region sequences that belong to the expanded haplogroups P and Q from our Southwest Pacific collection. The coalescence dates for the largest P and Q branches (P1 and Q1) are similar to each other (approximately 50,000 years old) and considerably older than prior estimates. Newly identified Q2, which was found in Island Melanesian samples just to the east, is somewhat younger by more than 10,000 years. Our coalescence estimates should be more reliable than prior ones because they were based on significantly larger samples as well as complete mtDNA-coding region sequencing. Our estimates are roughly in accord with the current suggested dates for the first settlement of New Guinea-Sahul. The phylogeography of P and Q indicates almost total (female) isolation of ancient New Guinea-Island Melanesia from Australia that may have existed from the time of the first settlement. While Q subsequently diversified extensively in New Guinea-Island Melanesia, it has not been found in Australia. The only shared mtDNA haplogroup between Australia and New Guinea identified to date remains one minor branch of P.     

Morphological and genetic differentiation of the African clupeid Limnothrissa miodon 34 years after its introduction to Lake Kivu

The evolutionary consequences of an artificial introduction of the clupeid Limnothrissa miodon from Lake Tanganyika into Lake Kivu, East Africa were examined. In 1959, 57 400 fry (mixture of Limnothrissa and the related clupeid, Stolothrissa tanganicae ), were released into Lake Kivu to boost fisheries production. Comparisons were made between respective source and transplant populations 34 years later (1993) using morphometrics ('truss' method), allozymes (29 enzyme-coding loci) and mitochondrial (mt) DNA variation (RFLP analysis of PCR-amplified ND5/6 genes). Significant morphological and genetic differentiation between source and transplant samples was detected, with a distinct clustering of Kivu Limnothrissa on respective dendrograms, especially at the morphometric and mtDNA levels. Differentiation within Lake Tanganyika was, however, consistently higher than that between lakes. Allozymic diversity was similar in samples from both lakes (Lake Tanganyika: heterozygosity = 0.0658, mean number of alleles=1.44; Lake Kivu: heterozygosity = 0.0655; mean number of alleles = 1.48), however, a significantly lower mtDNA haplotype diversity was detected in Lake Kivu (Lake Tanganyika: 0.905; Lake Kivu: 0.755). Data suggest that high post-introduction mortality and various demographic factors reduced the effective population size of the introduced population to tens rather than thousands of individuals, resulting in a reduction in genetic diversity and founder effect.     

Two Reproductive Life History Types of Kokanee, Onchorynchus nerka, Exhibit Multivariate Morphometric and Protein Genetic Differentiation

Two reproductive types of kokanee are found in Okanagan Lake, British Columbia: one form that spawns in streams, and another that spawns approximately 2–4 weeks later along beaches of the lake. We examined the levels and patterns of genetic and morphometric variation among three populations (1 beach and 2 stream populations) to better understand life history differentiation. We assayed allozyme variation at 74 loci and identified 15 P_0.095 loci. Average F_ST was 0.041 among the three samples; the two stream-spawning populations grouped together in genetic distance analyses. We examined multivariate morphometric variation and fin size/shape variation using 35 truss characters. Populations did not sort morphologically by spawning type in principal component and relative warp analyses. Instead both analyses indicated that one stream-spawning population (Peachland Creek) was significantly more robust and had shallower caudal fins in comparison to the other samples. Second, clear multivariate shape differences between males and females were identified involving jaw size, mid-body dimensions, and caudal fin shape. A simple bivariate plot of tail `forkness' against fork length demonstrated that males had more forked tails and females had flattened tails. Level of differentiation of secondary sexual characteristics did not vary between the spawning types, although the beach-spawning population and one stream-spawning population did not show the strong, gender-discriminating variability in tail forkness. Although these two reproductive life history types of kokanee form discrete genetic groups, environmental differences are apparently insufficient to effect consistent differences in body shape, or fin size and shape between stream and beach-spawning morphs.     

Morphological diversity of the <Emphasis Type="BoldItalic">Cynoscion</Emphasis> group (Perciformes: Sciaenidae) in the Gulf of Guayaquil region,Ecuador: A comparative approach

Synopsis We assess morphological diversity of species of the Cynoscion group in the Gulf of Guayaquil (GOG) using traditional morphometric methods. Five species from the GOG assemblage (C. albus, C. analis, C. phoxocephalus, C. squamipinnis, and Isopisthus remifer) are compared to four species from a relatively well-studied assemblage in the western Atlantic (C. arenarius, C. nebulosus, C. nothus, and C. regalis). The two regional species assemblages broadly overlap in morphology, but sympatric species segregate relatively well within each assemblage. The GOG species segregate primarily along the major axis of shape variation in the study, which is associated with variation in the anal, second dorsal, and caudal fins. The western Atlantic species segregate primarily along the second major axis of shape variation, which is most strongly associated with variation in gill raker length, and less strongly with pectoral fin length, eye diameter, and length of the third dorsal spine. Patterns of morphological divergence among the western Atlantic species support the hypothesis that morphological divergence is associated with ecological divergence. Comparisons across assemblages indicate that morphological divergence among species in the GOG is substantial. Consequently, Cynoscion species in the GOG may be highly divergent in ecological habits, which would have important management implications, but further ecological research is needed. This study provides a first glimpse into the major patterns of morphological diversification in the Cynoscion group.¹Bryant D., E. Rodenburg, T. Cox & D. Nielsen. 1995. Coastlines at Risk: an Index of Potential Development-Related Threats to Coastal Ecosystems. WRI Indicator Brief, World Resources Institute, Washington, D.C.     

The signal crayfish is not a single species: cryptic diversity and invasions in the Pacific Northwest range of Pacifastacus leniusculus

1. We used historical sources, morphology‐based taxonomy and mtDNA sequence data to address questions about the signal crayfish Pacifastacus leniusculus. These included evaluating unrecognised cryptic diversity and investigating the extent to which P. leniusculus may have been introduced within its presumed native range in the Pacific Northwest region of North America. Our study builds and expands on Pacific Northwest phylogeographic knowledge, particularly related to patterns of glacial refugia for freshwater species. 2. Extensive collections (824 specimens) from British Columbia (Canada), Idaho, Nevada, Oregon and Washington (United States) were used to characterise P. leniusculus at the mitochondrial 16S rRNA gene. Genetic groups within the species were elucidated by phylogenetics and amova ; evolutionary relationships within the most common and diverse group were investigated using a statistical parsimony haplotype network, a nested amova , and tests of isolation by distance. Morphological measurements were used to relate findings of molecular analyses to three historically recognised P. leniusculus subspecies and characterise cryptic diversity by morphology. 3. We found substantial cryptic diversity, with three groups highly distinct from P. leniusculus in discrete geographic regions: the Chehalis River glacial refugium, Central Oregon and the Okanagan Plateau. Disjunct distributions of P. leniusculus relative to these cryptic groups and known patterns of Pleistocene glaciation and landscape evolution cast doubt on whether P. leniusculus is native to some areas such as coastal drainages of northern Washington and southern British Columbia. Morphological traits previously used to characterise P. leniusculus subspecies still persist but may be incapable of distinguishing P. leniusculus from newly discovered cryptic groups. 4. Cryptic diversity found within P. leniusculus highlights the pressing need for a thorough investigation of the genus Pacifastacus using data based on more extensive gene and taxon sampling. It also warrants conservation attention, as introductions of P. leniusculus within the Pacific Northwest may carry risks of hybridisation and introgression for cryptic groups. Owing to high genetic diversity and limited dispersal capacity relative to more vagile organisms like freshwater fish, crayfish of the genus Pacifastacus offer powerful potential insights into the geological history and phylogeography of the Pacific Northwest region. Finally, by shedding light on the long‐neglected native range of P. leniusculus, our results should also better inform our understanding of potential source populations for, and the ecology of, this important invasive species in regions including Europe, Japan and elsewhere in North America.