Four new species and two new genera of Metapseudidae (Crustacea: Tanaidacea: Apseudomorpha) from Australian coral reefs.

This paper presents the descriptions of two new genera and four new metapseudid species collected from the coral reefs of Ningaloo and Heron Island in north-western and eastern Australia, respectively. Two of the species, Curtipleon chadi n. sp., and Creefs heronum n. gen. n. sp. are members of the subfamily Synapseudinae, one, Msangia mussida n. sp. is a member of the subfamily Msangiinae and one Bamberus jinigudirus n. gen. n. sp. is a member of the subfamily Chondropodinae. With the exception of M mussida that was found on live coral, all of the species were associated with dead corals.

First record of Tanaidacea (Crustacea) from a deep-sea coral reef in the Gulf of Guinea.

Four undescribed species of Tanaidacea were discovered during a baseline monitoring program conducted off the coast of Ghana. The specimens came from a deep-water reef largely composed of the ahermatypic coral, Lophelia pertusa. The tanaidacean material was collected during November 2012 onboard the RV Dr Fridtjof Nansen using a van Veen grab in depths of between 375 and 386 m. Three of the new species described herein are tanaidomorphans belonging to the genera Bathyleptochelia (Leptocheliidae), Pseudotanais (Pseudotanaidae) and Cryptocopoides (Cryptocopidae). The fourth species, an apseudomorphan, belongs to Calozodion (Metapseudidae), a genus hitherto known only from shallow waters (<200 m). This report constitutes the first records of tanaidaceans from a deep-sea Lophelia reef.

Distributional records of Ross Sea (Antarctica) Tanaidacea from museum samples stored in the collections of the Italian National Antarctic Museum (MNA) and the New Zealand National Institute of Water and Atmospheric Research (NIWA).

Here we present distributional records for Tanaidacea specimens collected during several Antarctic expeditions to the Ross Sea: the Italian PNRA expeditions ("V", 1989/1990; "XI", 1995/1996; "XIV", 1998/1999; "XIX", 2003/2004; "XXV", 2009/2010) and the New Zealand historical (New Zealand Oceanographic Institute, NZOI, 1958-1961) and recent ("TAN0402 BIOROSS" voyage, 2004 and "TAN0802 IPY-CAML Oceans Survey 20/20" voyage, 2008) expeditions. Tanaidaceans were obtained from bottom samples collected at depths ranging from 16 to 3543 m by using a variety of sampling gears. On the whole, this contribution reports distributional data for a total of 2953 individuals belonging to 33 genera and 50 species. All vouchers are permanently stored in the Italian National Antarctic Museum collection (MNA), Section of Genoa (Italy) and at the National Institute of Water and Atmospheric Research (NIWA Invertebrate Collection), Wellington (New Zealand).

Diversity of Tanaidacea (Crustacea: Peracarida) in the world's oceans--how far have we come?

Tanaidaceans are small peracarid crustaceans which occur in all marine habitats, over the full range of depths, and rarely into fresh waters. Yet they have no obligate dispersive phase in their life-cycle. Populations are thus inevitably isolated, and allopatric speciation and high regional diversity are inevitable; cosmopolitan distributions are considered to be unlikely or non-existent. Options for passive dispersion are discussed. Tanaidaceans appear to have first evolved in shallow waters, the region of greatest diversification of the Apseudomorpha and some tanaidomorph families, while in deeper waters the apseudomorphs have subsequently evolved two or three distinct phyletic lines. The Neotanaidomorpha has evolved separately and diversified globally in deep waters, and the Tanaidomorpha has undergone the greatest evolution, diversification and adaptation, to the point where some of the deep-water taxa are recolonizing shallow waters. Analysis of their geographic distribution shows some level of regional isolation, but suffers from inclusion of polyphyletic taxa and a general lack of data, particularly for deep waters. It is concluded that the diversity of the tanaidomorphs in deeper waters and in certain ocean regions remains to be discovered; that the smaller taxa are largely understudied; and that numerous cryptic species remain to be distinguished. Thus the number of species currently recognized is likely to be an order of magnitude too low, and globally the Tanaidacea potentially rival the Amphipoda and Isopoda in diversity.

The magnitude of global marine species diversity.

BACKGROUND: The question of how many marine species exist is important because it provides a metric for how much we do and do not know about life in the oceans. We have compiled the first register of the marine species of the world and used this baseline to estimate how many more species, partitioned among all major eukaryotic groups, may be discovered. RESULTS: There are ∼226,000 eukaryotic marine species described. More species were described in the past decade (∼20,000) than in any previous one. The number of authors describing new species has been increasing at a faster rate than the number of new species described in the past six decades. We report that there are ∼170,000 synonyms, that 58,000-72,000 species are collected but not yet described, and that 482,000-741,000 more species have yet to be sampled. Molecular methods may add tens of thousands of cryptic species. Thus, there may be 0.7-1.0 million marine species. Past rates of description of new species indicate there may be 0.5 ± 0.2 million marine species. On average 37% (median 31%) of species in over 100 recent field studies around the world might be new to science. CONCLUSIONS: Currently, between one-third and two-thirds of marine species may be undescribed, and previous estimates of there being well over one million marine species appear highly unlikely. More species than ever before are being described annually by an increasing number of authors. If the current trend continues, most species will be discovered this century.