Dennis P. Gordon

Application of Bryozoan zoarial growth-form studies in facies analysis of non-tropical carbonate deposits in New Zealand

Abstract The fragmental remains of bryozoan colonies are the dominant skeletal contributor in many modern and ancient occurrences of non-tropical shelf carbonate deposits. The taxonomic complexity of the Bryozoa, the difficulties of systematic classification except by specialists, the wide range of particle sizes and of preservation state in the carbonate deposits, and the often well-cemented nature of host limestones, all limit the sedimentological interpretation of the commonly diverse bryozoan component. However, following the pioneer work of Stach in the 1930s, the potential exists for sedimentologists to obtain useful (paleo)environmental information about the deposits by recording simply the nature and relative abundances of the various growth shapes of the bryozoan material, known as their zoarial (colonial) growth forms. Here we propose a simple descriptive terminology, covering both cheilostome and cyclostome bryozoans, that involves four main growth forms (encrusting, erect rigid, erect flexible and free-living) and a selection of subcategories based on shape. Identification of these habitat-related growth-form types is aided by reference to line drawings, specimen photographs and photomicrographs of thin-section slices. The scheme is illustrated by examining briefly some possible environmental controls on the spatial and/or time variations in the nature and distribution of colonial growth forms in several examples of modern and Tertiary bryozoan-dominated carbonate deposits in New Zealand. We anticipate that the routine description and quantification of bryozoan colonial growth types in non-tropical carbonates generally will facilitate the recognition and interpretation of contrasting (sub)facies within the global foramol/bryomol group of carbonate deposits.

A Higher Level Classification of All Living Organisms

We present a consensus classification of life to embrace the more than 1.6 million species already provided by more than 3,000 taxonomists’ expert opinions in a unified and coherent, hierarchically ranked system known as the Catalogue of Life (CoL). The intent of this collaborative effort is to provide a hierarchical classification serving not only the needs of the CoL’s database providers but also the diverse public-domain user community, most of whom are familiar with the Linnaean conceptual system of ordering taxon relationships. This classification is neither phylogenetic nor evolutionary but instead represents a consensus view that accommodates taxonomic choices and practical compromises among diverse expert opinions, public usages, and conflicting evidence about the boundaries between taxa and the ranks of major taxa, including kingdoms. Certain key issues, some not fully resolved, are addressed in particular. Beyond its immediate use as a management tool for the CoL and ITIS (Integrated Taxonomic Information System), it is immediately valuable as a reference for taxonomic and biodiversity research, as a tool for societal communication, and as a classificatory “backbone” for biodiversity databases, museum collections, libraries, and textbooks. Such a modern comprehensive hierarchy has not previously existed at this level of specificity.

Coral‐like bryozoan growths in Tasman Bay, and their protection to conserve commercial fish stocks

Abstract Mounds of ‘coral’ off Separation Point, Tasman Bay, which have recently been protected to conserve ecologically associated commercial fish species, are predominantly growths of Bryozoa. Two species (Celleporaria agglutinans, Hip‐pomenella vellicata) make up the bulk of these structures. Trawling through the ‘coral’ grounds has affected the fish populations to the extent that an area has been closed to trawling to conserve stocks.

Marine Biodiversity of Aotearoa New Zealand

The marine-biodiversity assessment of New Zealand (Aotearoa as known to Māori) is confined to the 200 nautical-mile boundary of the Exclusive Economic Zone, which, at 4.2 million km2, is one of the largest in the world. It spans 30° of latitude and includes a high diversity of seafloor relief, including a trench 10 km deep. Much of this region remains unexplored biologically, especially the 50% of the EEZ deeper than 2,000 m. Knowledge of the marine biota is based on more than 200 years of marine exploration in the region. The major oceanographic data repository is the National Institute of Water and Atmospheric Research (NIWA), which is involved in several Census of Marine Life field projects and is the location of the Southwestern Pacific Regional OBIS Node; NIWA is also data manager and custodian for fisheries research data owned by the Ministry of Fisheries. Related data sources cover alien species, environmental measures, and historical information. Museum collections in New Zealand hold more than 800,000 registered lots representing several million specimens. During the past decade, 220 taxonomic specialists (85 marine) from 18 countries have been engaged in a project to review New Zealands entire biodiversity. The above-mentioned marine information sources, published literature, and reports were scrutinized to give the results summarized here for the first time (current to 2010), including data on endemism and invasive species. There are 17,135 living species in the EEZ. This diversity includes 4,315 known undescribed species in collections. Species diversity for the most intensively studied phylum-level taxa (Porifera, Cnidaria, Mollusca, Brachiopoda, Bryozoa, Kinorhyncha, Echinodermata, Chordata) is more or less equivalent to that in the ERMS (European Register of Marine Species) region, which is 5.5 times larger in area than the New Zealand EEZ. The implication is that, when all other New Zealand phyla are equally well studied, total marine diversity in the EEZ may be expected to equal that in the ERMS region. This equivalence invites testable hypotheses to explain it. There are 177 naturalized alien species in New Zealand coastal waters, mostly in ports and harbours. Marine-taxonomic expertise in New Zealand covers a broad number of taxa but is, proportionately, at or near its lowest level since the Second World War. Nevertheless, collections are well supported by funding and are continually added to. Threats and protection measures concerning New Zealands marine biodiversity are commented on, along with potential and priorities for future research.

'Lophenteropneust' hypothesis refuted by collection and photos of new deep-sea hemichordates.

The deep ocean is home to a group of broad-collared hemichordates—the so-called ‘lophenteropneusts’—that have been photographed gliding on the sea floor but have not previously been collected. It has been claimed that these worms have collar tentacles and blend morphological features of the two main hemichordate body plans, namely the tentacle-less enteropneusts and the tentacle-bearing pterobranchs. Consequently, lophenteropneusts have been invoked as missing links to suggest that the former evolved into the latter. The most significant aspect of the lophenteropneust hypothesis is its prediction that the fundamental body plan within a basal phylum of deuterostomes was enteropneust-like. The assumption of such an ancestral state influences ideas about the evolution of the vertebrates from the invertebrates. Here we report on the first collected specimen of a broad-collared, deep-sea enteropneust and describe it as a new family, genus and species. The collar, although disproportionately broad, lacks tentacles. In addition, we find no evidence of tentacles in the available deep-sea photographs (published and unpublished) of broad-collared enteropneusts, including those formerly designated as lophenteropneusts. Thus, the lophenteropneust hypothesis was based on misinterpretation of deep-sea photographs of low quality and should no longer be used to support the idea that the enteropneust body plan is basal within the phylum Hemichordata.

Adventive occurrence of the fouling serpulid Ficopomatus enigmaticus (Polychaeta) in New Zealand

Abstract The exotic marine‐fouling polychaete Ficopomatus enigmaticus (Fauvel) is recorded and described from New Zealand. Its sudden occurrence in New Zealand around 1967 was marked by its ecological prominence in estuaries of Whangarei and Auckland Harbours, as a nuisance species on submerged artificial structures including pleasure craft and power station intake pipes.

Paleoecology of a late Eocene mobile rockground biota from North Otago, New Zealand

A distinctive mobile pebble and cobble rockground biota of Late Eocene age is described from volcaniclastic sediments between Oamaru and Kakanui, North Otago, New Zealand. Thousands of subangular to subrounded basaltic pebbles and cobbles are encrusted with a diverse range of very well-preserved epibionts including crustose coralline algae, serpulids, bivalves, foraminifera, brachiopods, and more than 70 species of cyclostome and cheilostome bryozoans. The preservation of thin sediment layers beneath and between encrusting bryozoan colonies indicates the probable occurrence, during life, of agglutinating microbial mats. The abundance of subspherical rhodoliths, the diversity of epibionts, and their occurrence on all faces of the volcanic clasts reflect intermediate levels of overturning and rolling in a moderately current-swept channel adjacent to small volcanic islands and seamounts. The occurrence of large foraminifera (Asteroclyna), bryozoans (including two extant species), and brachiopods with warm-water affinities indicates subtropical sea temperatures and water depths of 25-50 m for this community, which represents one of the few described Cenozoic examples of a mobile rockground biota.

Bryozoan frontal shields: studies on umbonulomorphs and impacts on classification

Umbonuloid frontal shields arc described in the type species of Lepraliella, Drepanophora, Frurionella, Tessaradoma, Hincksipora, Stephanopora, and Pseudolepralia. Consequences to classification include the following: the family group names Lepralielloidea and Lepralicllidae have subjective priority over Umbonuloidea and Celleporariidae, respectively; Cylindroporeh is excluded from the Tessaradomidae and included in the Gigantoporidae; Tessarudoma bifax Cheetham is included in Srnithsonius (Bifaxariidae); Hincksiporidae is confirmed as a family of Lepralielloidea; Stephanoporu, with newly discovered dimorphic orifices, comprises two species which are the basis for a new exechonellid subfamily Stephanoporinae; and a new umbonulomorph superfamily, Pseudolepralioidea, is established for Pseudolepraliu (Pseudolepraliidae). Kladapheles gen.n., is established for an erect branching species of Lepraliellidae from New Zealand.

Matrotrophy and placentation in invertebrates: a new paradigm

Matrotrophy, the continuous extra‐vitelline supply of nutrients from the parent to the progeny during gestation, is one of the masterpieces of nature, contributing to offspring fitness and often correlated with evolutionary diversification. The most elaborate form of matrotrophy—placentotrophy—is well known for its broad occurrence among vertebrates, but the comparative distribution and structural diversity of matrotrophic expression among invertebrates is wanting. In the first comprehensive analysis of matrotrophy across the animal kingdom, we report that regardless of the degree of expression, it is established or inferred in at least 21 of 34 animal phyla, significantly exceeding previous accounts and changing the old paradigm that these phenomena are infrequent among invertebrates. In 10 phyla, matrotrophy is represented by only one or a few species, whereas in 11 it is either not uncommon or widespread and even pervasive. Among invertebrate phyla, Platyhelminthes, Arthropoda and Bryozoa dominate, with 162, 83 and 53 partly or wholly matrotrophic families, respectively. In comparison, Chordata has more than 220 families that include or consist entirely of matrotrophic species. We analysed the distribution of reproductive patterns among and within invertebrate phyla using recently published molecular phylogenies: matrotrophy has seemingly evolved at least 140 times in all major superclades: Parazoa and Eumetazoa, Radiata and Bilateria, Protostomia and Deuterostomia, Lophotrochozoa and Ecdysozoa. In Cycliophora and some Digenea, it may have evolved twice in the same life cycle. The provisioning of developing young is associated with almost all known types of incubation chambers, with matrotrophic viviparity more widespread (20 phyla) than brooding (10 phyla). In nine phyla, both matrotrophic incubation types are present. Matrotrophy is expressed in five nutritive modes, of which histotrophy and placentotrophy are most prevalent. Oophagy, embryophagy and histophagy are rarer, plausibly evolving through heterochronous development of the embryonic mouthparts and digestive system. During gestation, matrotrophic modes can shift, intergrade, and be performed simultaneously. Invertebrate matrotrophic adaptations are less complex structurally than in chordates, but they are more diverse, being formed either by a parent, embryo, or both. In a broad and still preliminary sense, there are indications of trends or grades of evolutionarily increasing complexity of nutritive structures: formation of (i) local zones of enhanced nutritional transport (placental analogues), including specialized parent–offspring cell complexes and various appendages increasing the entire secreting and absorbing surfaces as well as the contact surface between embryo and parent, (ii) compartmentalization of the common incubatory space into more compact and ‘isolated’ chambers with presumably more effective nutritional relationships, and (iii) internal secretory (‘milk’) glands. Some placental analogues in onychophorans and arthropods mimic the simplest placental variants in vertebrates, comprising striking examples of convergent evolution acting at all levels—positional, structural and physiological.

Bathymetric distributions of modern populations of some common Cenozoic Bryozoa from New Zealand, and paleodepth estimation

Abstract Paleodepth inference from fossils often involves application of the principle of taxonomic uniformitarianism using known depth ranges of modern populations belonging to the same or closely related species. Bryozoans are abundant on the continental shelf around New Zealand at the present day but their potential as paleodepth indicators in the Cenozoic, where they dominate many fossil assemblages, has not been explored. Here, we survey the bathymetric distributions of four readily identifiable and common species (Cinctipora elegans, Attinopora zealandica, Diaperoecia purpurascens, and Celleporaria emancipata) plus one distinctive ecological group of bryozoans (tube‐building symbionts of hermit crabs), all of which are well represented in the Neogene fossil record of New Zealand. Data on the benthic stations containing these bryozoans in the extensive oceanographic collections at the National Institute of Water & Atmospheric Research reveals wide bathymetric distributions which constrain their use in estimating paleodepth from fossil occurrences. Total depth ranges were found to be: Cinctipora elegans, 17–914 m; Attinopora zealandica, 35–1156 m; Diaperoecia purpurascens, 0–1156 m; Celleporaria emancipata, 68–690 m; hermit crab tube builders, 0–252 m. A localised analysis of occurrences and abundances of Cinctipora elegans and Diaperoecia purpurascens off Otago Peninsula was also conducted. This analysis confirmed that these species occur over a large depth range on the Otago shelf. In C. elegans, colony abundance peaked strongly between 75 and 100 m off Otago Peninsula, a relatively narrow depth range. Despite their wide bathymetric distributions, several of the species surveyed here may eventually prove useful as paleodepth indicators because of their morphological plasticity which, by analogy with other bryozoans, is probably a response to environmental variables, some correlated with depth. Data are also presented on the geographic distributions of the target bryozoans.