The first recent species of the unusual brachiopod Kakanuiella (Thecideidae) from New Zealand deep waters

A new thecideid brachiopod species Kakanuiella chathamensis sp. nov. is described from deep waters on the Chatham Rise, east of South Island, New Zealand. The new species bears an unusual character combination in the shell morphology of its dorsal valve, displaying a mixture of diagnostic characters of both Recent thecideid subfamilies Thecidellininae and Lacazellinae. The resultant consequences for the systematic position of the genus Kakanuiella are discussed.     

Evolution and phylogeny of the New Zealand cicada genus Kikihia Dugdale (Homoptera: Auchenorrhyncha: Cicadidae) with special reference to the origin of the Kermadec and Norfolk Islands' species

Aim Determine the phylogeny and dispersal patterns of the cicada genus Kikihia in New Zealand and the origin of the Norfolk, Kermadec, and Chatham Island cicadas. Location New Zealand, Norfolk Island, Kermadec Islands and Chatham Island. Methods DNA sequences from 16 species and four soon to be described species of cicadas from New Zealand and Norfolk Island (Australia) were examined. A total of 1401 base pairs were analysed from whole genome extraction of three mitochondrial genes (cytochrome oxidase subunit II, ATPase6 and ATPase8). These DNA sequences were aligned and analysed using standard likelihood approaches to phylogenetic analysis. Dates of divergences between clades were determined using a molecular clock based on Bayesian statistics. Results Most species in the genus Kikihia diverged between 3 and 5 million years ago (Ma) coincident with a period of rapid mountain building in New Zealand. Cicada species on the Kermadec and Norfolk Islands invaded recently from New Zealand and are closely related to the New Zealand North Island species Kikihia cutora. Main conclusions Speciation in the genus Kikihia was likely due in large part to the appearance of new habitats associated with the rise of the Southern Alps, starting c. 5 Ma. Dispersal of Kikihia species within mainland New Zealand probably occurred gradually rather than through long‐distance jumps. However, invasion of Norfolk, the Kermadecs and Chatham Islands had to have occurred through long‐distance dispersal.     

Anzygina, a new genus for some Australasian microleafhopper species formerly placed in the genus Zygina Fieber (Cicadellidae: Typhlocybinae: Erythroneurini)

Species of Erythroneurini (Cicadellidae: Typhlocybinae) currently placed in the genus Zygina and found in Australia, New Zealand and some neighbouring islands are transferred to the new genus Anzygina , type species Erythroneura sidnica Kirkaldy, following comparison with the type species of the genus: Typhlocyba nivea Mulsant and Rey. New combinations are Anzygina sidnica (Kirkaldy), Anzygina honiloa (Kirkaldy), Anzygina melanogaster (Kirkaldy) and Anzygina sativae (Evans) from Australia, Anzygina toetoe (Cumber), Anzygina agni (Knight), Anzygina dumbletoni (Ghauri) and Anzygina ramsayi (Knight) from New Zealand, Anzygina zealandica (Myers) from Australia and New Zealand, Anzygina jowettae (Knight) from Norfolk Island and Anzygina medioborealis (Ghauri) from Papua New Guinea. Lectotypes are designated for Erythroneura honiloa Kirkaldy and E. sidnica Kirkaldy. Anzygina billi sp.n. is described from SE Qld, and Anzygina barrattae sp.n. is described from the South Island of New Zealand. A. agni is a new record for Australia and is presumed to be Australian in origin. A. dumbletoni has a distribution which suggests that it also is introduced to New Zealand although its origins are not known. A. ramsayi, A. barrattae and A. toetoe , all of which appear to be New Zealand endemics, show affinity with each other based on aedeagal structure. A key to these species, based on males, is provided. The lack of male syntypes for Erythroneura honiala Kirkaldy and Erythroneura lubra Kirkaldy precludes establishment of their identities relative to other species of the genus, and both names are regarded as having nomen dubium status. Australian species not transferred to Anzygina are Zygina evansi (Ross) and Zygina ipoloa (Kirkaldy), both of which belong elsewhere.     

Biogeographical and phylogeographical relationships of the bathyal ophiuroid fauna of the Macquarie Ridge, Southern Ocean

There are relatively few studies examining the latitudinal distribution of polar, subantarctic and temperate faunas on the bathyal seafloor across the Southern Ocean. Here, we investigate the relationship between the subantarctic Macquarie Ridge and adjacent regions of Antarctica (including the Ross Sea) and temperate Australia and New Zealand at depths of 200–2,500 m. We study the fauna at two levels of classification (1) morpho-species (MSPs) accepted by taxonomists and (2) evolutionary significant units defined as reciprocally monophyletic clades derived from phylogenies of mitochondrial DNA. The ophiuroid fauna on the Macquarie Ridge has a predominantly temperate origin, with far more MSPs shared with south-eastern Australia (78 % of species) and southern New Zealand (83 %) than neighbouring Antarctic regions (33 %). However, this asymmetry also reflects the relative species richness of these regions. Many species that are shared between Antarctica and the Macquarie Ridge have diverged into distinct mtDNA lineages indicative of a recent barrier to gene flow.     

Biogeographic and bathymetric ranges of Atlantic deep-sea echinoderms and ascidians: the role of larval dispersal

Dispersal plays an important role in the establishment and maintenance of biodiversity and, for most deep-sea benthic marine invertebrates, it occurs mainly during the larval stages. Therefore, the mode of reproduction (and thus dispersal ability) will affect greatly the biogeographic and bathymetric distributions of deep-sea organisms. We tested the hypothesis that, for bathyal and abyssal echinoderms and ascidians of the Atlantic Ocean, species with planktotrophic larval development have broader biogeographic and bathymetric ranges than species with lecithotrophic development. In comparing two groups with lecithotrophic development, we found that ascidians, which probably have a shorter larval period and therefore less dispersal potential, were present in fewer geographic regions than elasipod holothurians, which are likely to have longer larval periods. For asteroids and echinoids, both the geographic and bathymetric ranges were greater for lecithotrophic than for planktotrophic species. For these two classes, the relationships of egg diameter with geographic and bathymetric range were either linearly increasing or non-monotonic. We conclude that lecithotrophic development does not necessarily constrain dispersal in the deep sea, probably because species with planktotrophic development may be confined to regions of high detrital input from the sea surface. Our data suggest that more information is necessary on lengths of larval period for different species to accurately assess dispersal in the deep sea.     

Tropidofusus ypotethys: a new genus and new species of Columbariidae (Mollusca: Gastropoda: Turbinelloidea)

ABSTRACT

The genus Tripidofusus n. gen. is proposed to include Tropidofusus ypotethys n. sp. from bathyal depths off New Zealand, as well as Fulgurofusus aequilonius and Columbarium benthocallis from the abyssal zones of the Bering Sea and Scotia Sea, respectively. Tropidofusus can be distinguished from both Fulgurofusus and Coluzea on the basis of its lower spire, prominent peripheral keel, long, thin siphonal canal, as well as in having a much thinner shell that lacks axial sculpture. The type species, Tropidofusus ypotethys n. sp., differs from its congeners in having a broader peripheral keel, smaller aperture and longer siphonal canal, as well as by inhabiting bathyal rather than abyssal depths. The genus is reviewed and the relationships of Tropidofusus to other supraspecific taxa within Columbariidae are discussed, as are relationships among the families within Turbinelloidea.

http://www.zoobank.org/urn:lsid:zoobank.org:pub:3CA568AD-1B6F-4D4E-9DF7-8377CABB8553     

<Emphasis Type="Italic">Didemnum bentarti</Emphasis> (Chordata: Tunicata) a new species from the Bellingshausen Sea,Antarctica

A new Antarctic species belonging to the genus Didemnum is described. The material was collected during the BENTART-03 cruise through the Bellingshausen Sea. The geographic and bathymetric distribution of the known Didemnum species from Antarctic and Subantarctic regions and a tabular key for the identification of these species are summarized.     

Do Rapoport's rule,the mid‐domain effect or the source–sink hypotheses predict bathymetric patterns of polychaete richness on the Pacific coast of South America?

Aim We evaluated the bathymetric gradient of benthic polychaete species richness from the Chilean coast, as well as its possible underlying causes. We tested three possible hypotheses to explain the richness gradient: (1) Rapoport's effect; (2) the mid‐domain effect (MDE); and (c) the source–sink hypothesis. Location South‐eastern Pacific coast of Chile. Methods The bathymetric gradient in richness was evaluated using the reported ranges of bathymetric distribution of 498 polychaete species, from the intertidal to abyssal zone (c. 4700 m). Rapoport's effect was evaluated by examining the relationship between bathymetric mid‐point and bathymetric range extent, and species richness and depth. The MDE was tested using the Monte Carlo simulation program. The source–sink hypothesis was tested through nestedness analysis. Results Species richness shows significant exponential decay across the bathymetric gradient. The pattern is characterized by a high presence of short‐ranged species on the continental shelf area; while only a few species reach abyssal depths, and they tend to show extremely wide bathymetric ranges. Our simulation analyses showed that, in general, the pattern is robust to sampling artefacts. This pattern cannot be reproduced by the MDE, which predicts a parabolic richness gradient. Rather, results agree with the predictions of Rapoport's effect. Additionally, the data set is significantly nested at species, genus and family levels, supporting the source–sink hypothesis. Main conclusions The sharp exponential decay in benthic polychaete richness across the bathymetric gradient supports the general idea that abyssal environments should harbour fewer species than shallower zones. This pattern may be the result of colonization–extinction dynamics, characterized by abyssal assemblages acting as ‘sinks’ maintained mainly by shallower ‘sources’. The source–sink hypothesis provides a conceptual and methodological framework that may shed light on the search for general patterns of diversity across large spatial scales.     

Phylogeography of a pan-Atlantic abyssal protobranch bivalve: implications for evolution in the Deep Atlantic

The deep sea is a vast and essentially continuous environment with few obvious barriers to gene flow. How populations diverge and new species form in this remote ecosystem is poorly understood. Phylogeographical analyses have begun to provide some insight into evolutionary processes at bathyal depths (<3000 m), but much less is known about evolution in the more extensive abyssal regions (>3000 m). Here, we quantify geographical and bathymetric patterns of genetic variation (16S rRNA mitochondrial gene) in the protobranch bivalve Ledella ultima, which is one of the most abundant abyssal protobranchs in the Atlantic with a broad bathymetric and geographical distribution. We found virtually no genetic divergence within basins and only modest divergence among eight Atlantic basins. Levels of population divergence among basins were related to geographical distance and were greater in the South Atlantic than in the North Atlantic. Ocean‐wide patterns of genetic variation indicate basin‐wide divergence that exceeds what others have found for abyssal organisms, but considerably less than bathyal protobranchs across similar geographical scales. Populations on either side of the Mid‐Atlantic Ridge in the North Atlantic differed, suggesting the Ridge might impede gene flow at abyssal depths. Our results indicate that abyssal populations might be quite large (cosmopolitan), exhibit only modest genetic structure and probably provide little potential for the formation of new species.     

Patterns of Deep-Sea Genetic Connectivity in the New Zealand Region: Implications for Management of Benthic Ecosystems

Patterns of genetic connectivity are increasingly considered in the design of marine protected areas (MPAs) in both shallow and deep water. In the New Zealand Exclusive Economic Zone (EEZ), deep-sea communities at upper bathyal depths (<2000 m) are vulnerable to anthropogenic disturbance from fishing and potential mining operations. Currently, patterns of genetic connectivity among deep-sea populations throughout New Zealand’s EEZ are not well understood. Using the mitochondrial Cytochrome Oxidase I and 16S rRNA genes as genetic markers, this study aimed to elucidate patterns of genetic connectivity among populations of two common benthic invertebrates with contrasting life history strategies. Populations of the squat lobster Munida gracilis and the polychaete Hyalinoecia longibranchiata were sampled from continental slope, seamount, and offshore rise habitats on the Chatham Rise, Hikurangi Margin, and Challenger Plateau. For the polychaete, significant population structure was detected among distinct populations on the Chatham Rise, the Hikurangi Margin, and the Challenger Plateau. Significant genetic differences existed between slope and seamount populations on the Hikurangi Margin, as did evidence of population differentiation between the northeast and southwest parts of the Chatham Rise. In contrast, no significant population structure was detected across the study area for the squat lobster. Patterns of genetic connectivity in Hyalinoecia longibranchiata are likely influenced by a number of factors including current regimes that operate on varying spatial and temporal scales to produce potential barriers to dispersal. The striking difference in population structure between species can be attributed to differences in life history strategies. The results of this study are discussed in the context of existing conservation areas that are intended to manage anthropogenic threats to deep-sea benthic communities in the New Zealand region.     

Population structure and biogeography of Hemiphaga pigeons (Aves: Columbidae) on islands in the New Zealand region

Aim The New Zealand avifauna includes lineages that lack close relatives elsewhere and have low diversity, characteristics sometimes ascribed to long geographic isolation. However, extinction at the population and species levels could yield the same pattern. A prominent example is the ecologically important pigeon genus Hemiphaga. In this study, we examined the population structure and phylogeography of Hemiphaga across islands in the region. Location New Zealand, Chatham Islands and Norfolk Island. Methods Mitochondrial DNA was sequenced for all species of the genus Hemiphaga. Sixty‐seven individuals from mainland New Zealand (Hemiphaga novaeseelandiae novaeseelandiae), six of the Chatham Islands sister species (Hemiphaga chathamensis), and three of the extinct Norfolk Island subspecies (Hemiphaga novaeseelandiae spadicea) were included in this study. Novel D‐loop and cytochrome b primers were designed to amplify DNA from museum samples. Additionally, five other mitochondrial genes were used to examine placement of the phylogenetic root. Results Analyses of mitochondrial DNA sequences revealed three Hemiphaga clades, consistent with the allopatric populations of recognized (sub)species on oceanic islands. Of the 23 D‐loop haplotypes among 67 New Zealand pigeons (Hemiphaga n. novaeseelandiae), 19 haplotypes were singletons and one haplotype was common and widespread. Population genetic diversity was shallow within and between New Zealand populations, indicating range expansion with high inter‐population exchange. Tentative rooting of the Hemiphaga clade with cyt b data indicates exchange between mainland New Zealand and the Chatham Islands prior to colonization of Norfolk Island. We found low genetic divergence between populations on New Zealand, the Chatham Islands and Norfolk Island, but deep phylogenetic divergence from the closest living relatives of Hemiphaga. Main conclusions The data are consistent with the hypothesis of population reduction during the Pleistocene and subsequent expansion from forest refugia. Observed mobility of Hemiphaga when feeding helps explain the shallow diversity among populations on islands separated by many hundreds of kilometres of ocean. Together with comparison of distribution patterns observed among birds of the New Zealand region, these data suggest that endemicity might represent not long occupancy of an area, but descent from geologically recent colonizations. We consider the role of lineage pruning in creating the impression of old endemicity.     

A new species of Lepidapedon Stafford, 1904 (Digenea: Lepocreadiidae) in the gadiform fish Coelorhinchus bollonsi McCann & McKnight (Macrouridae) from Chatham Rise,New Zealand

Lepidapedon blairi n. sp. is described from the gut of Coelorhinchus bollonsi from a depth of 570 m on the Chatham Rise off the east coast of South Island, New Zealand. It is distinguished from its congeners by its vitelline distribution, which does not extend much anterior to the ovary, and the extent of the excretory vesicle, which does not reach the posterior testis.     

Macrofaunal crustaceans in the benthic boundary layer from the shelf break to abyssal depths in the Ross Sea (Antarctica)

The New Zealand International Polar Year–Census of Antarctic Marine Life (NZ IPY-CAML) project added to previous benthic studies in the Ross Sea by extending sampling north from the continental shelf to previously unsampled areas of the shelf break, slope, abyssal plain and seamounts in the region. The aim of the current study is to give first insights into the deep-sea community structure of the Ross Sea focussing on a component of the benthic boundary layer that is macrofaunal crustaceans collected one metre above the seafloor. We assess changes in Ross Sea crustacean community composition from the shelf break (474 m) to the abyss (3,490 m) and compare the Ross Sea crustacean fauna to areas elsewhere in the Southern Ocean. Analyses reveal high relative abundances, suggesting an important role in the food web. Among the peracarid crustaceans, there was a decline in the proportion of amphipods with increasing depth. Three of 15 isopod families (Acanthaspidiidae, Nannoniscidae and Desmosomatidae) were identified to species level and about 72 % of the species were new to science. Isopod diversity in the Ross Sea abyss appears to be comparable to that in the highly speciose Weddell deep sea. Standardised sampling of these crustacean communities allows setting the biodiversity of the Ross Sea into a global context.     

The food and feeding relationships of black oreo, Allocyttus niger, smooth oreo, Pseudocyttus maculatus, and eight other fish species from the continental slope of the south-west Chatham Rise, New Zealand

The food and feeding habits of black oreo and smooth oreo sampled at depths of 600–1200 m from the south-west Chatham Rise in 1983 are described, with notes on prey of eight other fish species. All these fish species fed benthopelagically. Black oreo preyed on hyperiid amphipods, salps and natant decapod crustaceans; smooth oreo on salps and amphipods. Dietary composition of both species changed with size of fish. Aspects of feeding relationships between the fish species were examined including dietary similarity and prey-size selection. Findings are compared with results of research on other New Zealand deepwater fish species.     

Lipid composition of the liver oil of deep-sea sharks from the Chatham Rise, New Zealand

Deep-sea sharks approach neutral buoyancy by means of a large liver that contains large amounts of low-density lipids, primarily squalene and diacyl glyceryl ether (DAGE). As an animal increases in size and matures sexually, many biochemical changes take place within the animal. It was hypothesized that maintenance of neutral buoyancy in deep-sea sharks involves fine-scale changes in the chemical composition of the liver oil as individual sharks grow and develop. To test this hypothesis, the lipid composition of liver oil for individuals of different size and sex of deep-sea sharks from the Chatham Rise, New Zealand was compared. The composition of liver oil varied within and among species. Several species contained large amounts of squalene and DAGE, whereas only traces of these lipids were present in other species. The amounts of squalene and DAGE in liver oil were inversely related, and squalene content tended to decrease as sharks increased in size. Species with high squalene levels (>80%) in liver oil were not abundant on the Chatham Rise, although levels of DAGE (a lipid of increasing commercial interest) were elevated in many species. Maintenance of neutral buoyancy in deep-sea sharks appears to involve changes in the composition of low-density liver lipids as the sharks increase in size and mature.     

A new subfamily and species of Ostracoda (Cylindroleberididae,Myodocopa) from the Chatham Rise (New Zealand)

Abstract

The second species of the genus, Macroasteropteron chathamensis sp. nov. is described in the present paper. It was collected from 1000 m depth during the New Zealand national biodiversity programme Ocean Survey 20/20 to the Chatham Rise and the Challenger Plateau. To accommodate this genus, a new subfamily Macroasteropteroninae is described herein. It is defined by the following autapomorphies: locking system on the shell; very small second segment on the second antenna (bearing no dorsal bristles); square shaped third and fourth segments on the same appendage; absence of dorsal bristles on the third segment of the male clasping organ; reverse position of the alpha and beta bristles on the maxillula; almost square shaped skirt on the sixth limb; and a bulbous terminal part of the seventh limb, which, in addition, does not have any bell-bearing bristles. A key to the four subfamilies of Cylindroleberididae is provided.     

Historic trawl data and recent information infers temporal change in the occurrence of squid in the diet of orange roughy (Hoplostethus atlanticus Collett) in New Zealand

A review of historical trawl data for orange roughy on Chatham Rise and Challenger Plateau, New Zealand, between the years 1984 and 1996 infers a shift in this species’ diet, with a progressive decline in the percentage occurrence of squid being apparent. On Chatham Rise, this decline in the percentage occurrence of squid appears to be compensated for by increases in the percentage occurrence of fish and crustaceans in orange roughy diet, whereas on Challenger Plateau, decreases in all of squid, fish and crustaceans are apparent. New orange roughy dietary data for 2004 from Chatham Rise is consistent with earlier data series, with further declines in the percentage occurrence of squid apparent. Declines in the occurrence of squid in the diet of orange roughy could be attributed to declines in the abundance of squid as a consequence of fisheries activity.     

Fish distributions along depth gradients of a sea mountain range conform to the mid‐domain effect

Species richness often peaks in the middle of bounded geographic domains (e.g. latitude, altitude or depth). Hump‐shaped richness distributions may be due to deterministic processes, such as adaptations to environmental variation. Alternatively, such distributions might also be due to stochastic process. The mid‐domain effect (MDE) posits that hump‐shaped richness distributions arise when species ranges are randomly arranged within the limits of the domain. We tested whether the MDE could account for the richness of bottom‐associated (demersal) fishes between 200 and 800 m on the Chatham Rise, New Zealand. We quantified the depth distributions of 59 fish species from 1891 research trawl catches made between 1991 and 2007. Results showed a broad plateau of high species richness near the centre of the domain (between 300 and 700 m), which was consistent with expectations of the MDE. Further, empirical species richness was better explained statistically by predictions of the MDE than models incorporating additional abiotic predictor variables. Our results deviated from previous studies that identified a greater richness of fishes in warmer, shallower depths with higher primary production. However, our study was conducted entirely below the euphotic zone, at depths where gradients are relatively weak, suggesting that support for the mid‐domain effect may increase across oceanic domains characterised by weak environmental gradients.     

Notes on the diet of seven grenadier fishes (Macrouridae) from the lower continental slope of Chatham Rise, New Zealand

Diets of 8 rarely sampled species of grenadiers were examined from the lower continental slope (1178 to 1837 m) on Chatham Rise, New Zealand and includes the first known records of the diet of Bathygadus cottoides, Coryphaenoides mcmillani, C. murrayi, and Idiolophorhynchus andriashevi. Most species fed benthopelagically on small crustaceans, e.g., calanoid copepods, amphipods and mysids and others.