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A new species of deep-sea yeti crab, Kiwa araonae , is described from a hydrothermal vent field, Mujin (“Misty Harbor”), at a depth of about 2000 m on the Australian-Antarctic Ridge (AAR), Southern Ocean. The Mujin vent field (62°11.79′S), in a large, unexplored gap in the Circum-Antarctic Ridge system, is the most southern record for a yeti crab to date. Kiwa araonae n. sp. is the fourth described species in the family Kiwaidae Macpherson, Jones and Segonzac, 2005, and the second known from the Southern Ocean. This new species differs morphologically from its three congeners by the having a nearly flat branchial region, relatively short rostrum, third sternite with parallel lateral margins, slender chela, straight fingers of the chela, and propodi of pereiopods 2-4 with three corneous spines on the flexor margins. The Bayesian phylogenetic tree and the genetic distance based on the mitochondrial 16S rRNA gene (408 bp) clearly indicate the distinctiveness of this species. The discovery of Kiwa araonae in the AAR suggests a possible biogeographic connection of the Southern Ocean vent faunas. The presence of a new hydrothermal vent field with endemic species in the AAR provides additional information on the global biogeography of deep-sea vent faunas.

The recent discovery of two new species of kiwaid squat lobsters on hydrothermal vents in the Pacific Ocean and in the Pacific sector of the Southern Ocean has prompted a re-analysis of Kiwaid biogeographical history. Using a larger alignment with more fossil calibrated nodes than previously, we consider the precise relationship between Kiwaidae, Chirostylidae and Eumunididae within Chirostyloidea (Decapoda: Anomura) to be still unresolved at present. Additionally, the placement of both new species within a new “Bristly” clade along with the seep-associated Kiwa puravida is most parsimoniously interpreted as supporting a vent origin for the family, rather than a seep-to-vent progression. Fossil-calibrated divergence analysis indicates an origin for the clade around the Eocene-Oligocene boundary in the eastern Pacific ~33–38 Ma, coincident with a lowering of bottom temperatures and increased ventilation in the Pacific deep sea. Likewise, the mid-Miocene (~10–16 Ma) rapid radiation of the new Bristly clade also coincides with a similar cooling event in the tropical East Pacific. The distribution, diversity, tree topology and divergence timing of Kiwaidae in the East Pacific is most consistent with a pattern of extinctions, recolonisations and radiations along fast-spreading ridges in this region and may have been punctuated by large-scale fluctuations in deep-water ventilation and temperature during the Cenozoic; further affecting the viability of Kiwaidae populations along portions of mid-ocean ridge.

We analyzed the diversity of bacterial epibionts and trophic ecology of a new species of Kiwa yeti crab discovered at two hydrothermal vent fields (E2 and E9) on the East Scotia Ridge (ESR) in the Southern Ocean using a combination of 454 pyrosequencing, Sanger sequencing, and stable isotope analysis. The Kiwa epibiont communities were dominated by Epsilon- and Gammaproteobacteria. About 454 sequencing of the epibionts on 15 individual Kiwa specimen revealed large regional differences between the two hydrothermal vent fields: at E2, the bacterial community on the Kiwa ventral setae was dominated (up to 75%) by Gammaproteobacteria, whereas at E9 Epsilonproteobacteria dominated (up to 98%). Carbon stable isotope analysis of both Kiwa and the bacterial epibionts also showed distinct differences between E2 and E9 in mean and variability. Both stable isotope and sequence data suggest a dominance of different carbon fixation pathways of the epibiont communities at the two vent fields. At E2, epibionts were putatively fixing carbon via the Calvin-Benson-Bassham and reverse tricarboxylic acid cycle, while at E9 the reverse tricarboxylic acid cycle dominated. Co-varying epibiont diversity and isotope values at E2 and E9 also present further support for the hypothesis that epibionts serve as a food source for Kiwa.

Microsatellite loci have been developed for three undescribed species discovered at hydrothermal vents on the East Scotia Ridge (ESR) in the Southern Ocean: a yeti crab, Kiwa sp. (Kiwaidae), a species of peltospiroid gastropod and a vent limpet, Lepetodrilus sp. (Lepetodrilidae). Nine, twelve and fourteen loci were developed for the three species respectively, with two loci deviating significantly from Hardy-Weinberg expectations. Observed heterozygosity ranged from 0.08 to 1 (means of 0.62, 0.44 and 0.63 for the three species respectively). These loci are being used to determine connectivity between vents at the northern and southern end of the ESR and between the ESR and the Kemp Caldera, a submerged part of the South Sandwich Island chain. These data will be crucial in understanding the ecology of the first hydrothermal vent communities discovered in the Southern Ocean. © 2013 Springer Science+Business Media Dordrecht.

The complete mitochondrial genome of Kiwa tyleri (Anomura, Chirostyloidea, Kiwaidae) was recovered by next generation sequencing. The mitogenome is 16,865 bp in length and contains 13 protein-coding genes (PCGs), 22 transfer RNAs (tRNAs), two ribosomal RNAs (rRNAs) and a 1525bp non-coding AT-rich region. This is the first mitogenome for the family Kiwaidae and the superfamily Chirostyloidea. The inversion of three consecutive genes (16S rRNA, tRNA-Val, 12S rRNA) was first reported for the Anomura. The phylogenetic tree indicated that Kiwaidae was close to Paguroidea and Lithodoidea rather than Galatheoidea.

The Yeti crab, Kiwa hirsuta Macpherson et al., is the single known species in a recently discovered crab family Kiwaidae (Decapoda: Galatheoidea) from deepsea hydrothermal vents. Its chelipeds, walking legs and the ventral surface of its cephalothorax are covered with dense setae that, in turn, are covered with clusters of filamentous bacteria, making the crab appear extraordinarily ‘hairy’. Electron microscopy revealed dense bacterial clusters attached to the chitinous outer layer of the setae. Molecular phylogenetic analyses revealed the setae-associated bacteria to be dominated by e-Proteobacteria (~56% of the recovered ribotypes), g-Proteobacteria (~25%) and Bacteroidetes (~10%). Fluorescence in situ microscopy confirmed the attachment of filamentous e-Proteobacteria on setae, but no specialized morphological structures appeared to exist for bacterial attachment. Key enzymes involved in the reductive tricarboxylic acid cycle (ATP-dependent citrate lyase) and sulfite oxidation or dissimilatory sulfate reduction (bidirectional APS reductase) were detected. Consequently, the potential for carbon fixation and cycling of reduced and oxidized sulfur appear to exist in the dense microflora that grows on the crab’s setae.

Hydrothermal vents in the Southern Ocean are the physiologically most isolated chemosynthetic environments known. Here, we describe Kiwa tyleri sp. nov., the first species of yeti crab known from the Southern Ocean. Kiwa tyleri belongs to the family Kiwaidae and is the visually dominant macrofauna of two known vent sites situated on the northern and southern segments of the East Scotia Ridge (ESR). The species is known to depend on primary productivity by chemosynthetic bacteria and resides at the warm-eurythermal vent environment for most of its life; its short-range distribution away from vents (few metres) is physiologically constrained by the stable, cold waters of the surrounding Southern Ocean. Kiwa tylerihas been shown to present differential life history adaptations in response to this contrasting thermal environment. Morphological adaptations specific to life in warm-eurythermal waters, as found on - or in close proximity of - vent chimneys, are discussed in comparison with adaptations seen in the other two known members of the family (K. hirsuta, K. puravida), which show a preference for low temperature chemosynthetic environments.

The deep-sea squat lobster Kiwa tyleri (also known as yeti crab) is the dominant macroinvertebrate inhabiting hydrothermal vents on the northern and southern segments of the East Scotia Ridge in the Southern Ocean. Here, we describe the first zoeal stage of the species—which is morphologically advanced—and provide evidence for its lecithotrophy in development. This morphologically advanced stage at hatching suggests that dispersal potential during early ontogeny may be limited. Adults of K. tyleri typically inhabit a warm-eurythermal, and spatially defined, temperature envelope of vent chimneys. In contrast, ovigerous females with late embryos are found away from these temperatures, off the vent site. This implies that at least part of embryogenesis takes place away from the chemosynthetic environment. Larvae are released into the cold waters of the Southern Ocean that are known to pose physiological limits on the survival of reptant decapods. Larval lecithotrophy may aid long developmental periods under these conditions and facilitate development independent of pronounced seasonality in primary production. It remains uncertain, however, how population connectivity between distant vent sites may be achieved.

1.Few species of reptant decapod crustaceans thrive in the cold-stenothermal waters of the Southern Ocean. However, abundant populations of a new species of anomuran crab, Kiwa tyleri, occur at hydrothermal vent fields on the East Scotia Ridge. 2.As a result of local thermal conditions at the vents, these crabs are not restricted by the physiological limits that otherwise exclude reptant decapods south of the polar front. 3.We reveal the adult life-history of this species by piecing together variation in microdistribution, body size-frequency, sex ratio, and ovarian and embryonic development, which indicates a pattern in the distribution of female Kiwaidae in relation to their reproductive development. 4.High-density "Kiwa" assemblages observed in close proximity to sources of vent fluids are constrained by the thermal limit of elevated temperatures and the availability of resources for chemosynthetic nutrition. Although adult Kiwaidae depend on epibiotic chemosynthetic bacteria for nutrition, females move offsite after extrusion of their eggs to protect brooding embryos from the chemically harsh, thermally fluctuating vent environment. Consequently, brooding females in the periphery of the vent field are in turn restricted by low-temperature physiological boundaries of the deep-water Southern Ocean environment. Females have a high reproductive investment in few, large, yolky eggs, facilitating full lecithotrophy, with the release of larvae prolonged, and asynchronous. After embryos are released, larvae are reliant on locating isolated active areas of hydrothermal flow in order to settle and survive as chemosynthetic adults. Where the cold water restricts the ability of all adult stages to migrate over long distances, these low temperatures may facilitate the larvae in the location of vent sites by extending the larval development period through hypometabolism.5.These differential life-history adaptations to contrasting thermal environments lead to a disjunct life history among males and females of Kiwa tyleri, which is key to their success in the Southern Ocean vent environment.6.We highlight the complexity in understanding the importance of life-history biology, in combination with environmental, ecological and physiological factors contributing to the overall global distribution of vent endemic species.

The chirostyloid squat lobster Pristinaspina gelasina from the Upper Cretaceous of Alaska is most closely related to members of the genus Kiwa (Kiwaidae) as indicated by the presence of supraocular spines, a medially carinate rostrum and similar carapace groove patterns. Evidence from morphology, stratigraphic position and molecular divergence estimates of extant chirostyloids supports its position in the stem of Kiwaidae. Pristinaspina, however, also differs significantly from kiwaids and is here assigned to a new family, Pristinaspinidae. The chief distinction between the free-living pristinaspinids and vent- or seep-associated kiwaids (and an important synapomorphy of the latter) is the enlargement of the metabranchial regions in kiwaids, which meet in the mid-line and separate the cardiac region from the intestinal region. The enlarged metabranchial regions of kiwaids may have improved respiration in poorly oxygenated, chemosynthetically affected waters. This appears to track a major shift in the deep-water ecology of kiwaiform squat lobsters, that is, the movement into chemosynthetic habitats.

The phylogeny of the superfamily Chirostyloidea (Decapoda: Anomura) has been poorly understood owing to limited taxon sampling and discordance between different genes. We present a nine-gene dataset across 15 chirostyloids, including all known yeti crabs (Kiwaidae), to improve the resolution of phylogenetic affinities within and between the different families, and to date key divergences using fossil calibrations. This study supports the monophyly of Chirostyloidea and, within this, a basal split between Eumunididae and a Kiwaidae–Chirostylidae clade. All three families originated in the Mid-Cretaceous, but extant kiwaids and most chirostylids radiated from the Eocene onwards. Within Kiwaidae, the basal split between the seep-endemic Kiwa puravida and a vent clade comprising Kiwa hirsuta and Kiwa spp. found on the East Scotia and Southwest Indian ridges is compatible with a hypothesized seep-to-vent evolutionary trajectory. A divergence date estimate of 13.4–25.9 Ma between the Pacific and non-Pacific lineages is consistent with Kiwaidae spreading into the Atlantic sector of the Southern Ocean via the newly opened Drake Passage. The recent radiation of Kiwaidae adds to the list of chemosynthetic fauna that appear to have diversified after the Palaeocene/Eocene Thermal Maximum, a period of possibly widespread anoxia/dysoxia in deep-sea basins.

5 Corresponding author Table of contents Abstract The parasitic isopod family Bopyridae contains approximately 600 species that parasitize calanoid copepods as larvae and decapod crustaceans as adults. In total, 105 species of these parasites (~18% of all bopyrids) are documented from Recent squat lobsters and porcelain crabs in the superfamilies Chirostyloidea and Galatheoidea. Aside from one endoparasite, all the bopyrids reported herein belong to the branchially infesting subfamily Pseudioninae. Approximately 29% (67 of 233 species) of pseudionine species parasitize squat lobsters and 16% (38 of 233 species) parasitize porcelain crabs. Bopyrids are found in five of six squat lobster families (lacking only in Kiwaidae) and the sole porcelain crab family Porcellanidae. Six pseudionine genera are shared between squat lobsters and porcelain crabs. The deepest bathymetric records of bopyrids on squat lobster hosts 5210 m , and records of swellings interpreted as indications of bopyrid presence in fossil host taxa are noted. Four nomenclatural issues are resolved and the proper form of citation for the French zoologist C. E. Hesse is provided. Biogeographic distributions for squat lobsters and porcelain crabs are discussed and compared to those of hermit crabs.

Rogers, Alex D. ... et. al.-- 17 pages, 6 figures, 2 tables, supporting information in https://doi.org/10.1371/journal.pbio.1001234, Since the first discovery of deep-sea hydrothermal vents along the Galápagos Rift in 1977, numerous vent sites and endemic faunal assemblages have been found along mid-ocean ridges and back-arc basins at low to mid latitudes. These discoveries have suggested the existence of separate biogeographic provinces in the Atlantic and the North West Pacific, the existence of a province including the South West Pacific and Indian Ocean, and a separation of the North East Pacific, North East Pacific Rise, and South East Pacific Rise. The Southern Ocean is known to be a region of high deep-sea species diversity and centre of origin for the global deep-sea fauna. It has also been proposed as a gateway connecting hydrothermal vents in different oceans but is little explored because of extreme conditions. Since 2009 we have explored two segments of the East Scotia Ridge (ESR) in the Southern Ocean using a remotely operated vehicle. In each segment we located deep-sea hydrothermal vents hosting high-temperature black smokers up to 382.8°C and diffuse venting. The chemosynthetic ecosystems hosted by these vents are dominated by a new yeti crab (Kiwa n. sp.), stalked barnacles, limpets, peltospiroid gastropods, anemones, and a predatory sea star. Taxa abundant in vent ecosystems in other oceans, including polychaete worms (Siboglinidae), bathymodiolid mussels, and alvinocaridid shrimps, are absent from the ESR vents. These groups, except the Siboglinidae, possess planktotrophic larvae, rare in Antarctic marine invertebrates, suggesting that the environmental conditions of the Southern Ocean may act as a dispersal filter for vent taxa. Evidence from the distinctive fauna, the unique community structure, and multivariate analyses suggest that the Antarctic vent ecosystems represent a new vent biogeographic province. However, multivariate analyses of species present at the ESR and at other deep-sea hydrothermal vents globally indicate that vent biogeography is more complex than previously recognised. © 2012 Rogers et al., The ChEsSo research programme was funded by a NERC Consortium Grant (NE/DO1249X/1) and supported by the Census of Marine Life and the Sloan Foundation, and the Total Foundation for Biodiversity (Abyss 2100)(SVTH) all of which are gratefully acknowledged. We also acknowledge NSF grant ANT-0739675 (CG and TS), NERC PhD studentships NE/D01429X/1(LH, LM, CNR), NE/H524922/1(JH) and NE/F010664/1 (WDKR), a Cusanuswerk doctoral fellowship, and a Lesley & Charles Hilton-Brown Scholarship, University of St. Andrews (PHBS)

The high level classification of the Galatheoidea, popularly known as squat lobsters, has been relatively stable for almost a century. Multiple recent studies of their interrelationships, however, have revealed significant incongruities between the traditional classification and phylogeny. The Aeglidae, Chirostylidae and Kiwaidae were recently removed to other superfamilies. On the basis of previous phylogenetic analyses, we herein revise the higher classification of the remaining Galatheoidea to comprise four families: Galatheidae, Munididae fam. nov., Munidopsidae, and Porcellanidae. The galatheoid families are both morphologically and ecologically distinct. Members of the Munidopsidae are distinguished by the absence or reduction of the maxilliped 1 flagellum and usually occur in outer slope or abyssal habitats. Members of the Munididae fam. nov. are united by the trifid or trispinous anterior margin of the carapace and usually occur at outer shelf or slope depths. The Galatheidae includes primarily shallow water species, united by a broad, triangular rostrum, and is most closely related to the porcelain crabs, Porcellanidae. The families of the Galatheoidea are diagnosed and a diagnostic key provided. Extant and fossil genera are listed for each galatheoid squat lobster family.

The monophyletic status of the squat lobster superfamily Galatheoidea has come under increasing doubt by studies using evidence as diverse as larval and adult somatic morphology, sperm ultrastructure, and molecular data. Here we synthesize phylogenetic data from these diverse strands, with the addition of new molecular and morphological data to examine the phylogeny of the squat lobsters and assess the status of the Galatheoidea. A total of 64 species from 16 of the 17 currently recognised anomuran families are included. Results support previous work pointing towards polyphyly in the superfamily Galatheoidea and Paguroidea, specifically, suggesting independent origins of the Galatheidae + Porcellanidae and the Chirostylidae + Kiwaidae. Morphological characters are selected that support clades resolved in the combined analysis and the taxonomic status of Galatheoidea sensu lato is revised. Results indicate that Chirostylidae are more closely related to an assemblage including Aegloidea, Lomisoidea and Paguroidea than to the remaining Galatheoidea and are referred to the superfamily Chirostyloidea to include the Chirostylidae and Kiwaidae. A considerable amount of research highlighting morphological differences supporting this split is discussed. The Galatheoidea sensu stricto is restricted to the families Galatheidae and Porcellanidae, and diagnoses for both Chirostyloidea and Galatheoidea are provided. Present results highlight the need for a detailed revision of a number of taxa, challenge some currently used morphological synapomorphies, and emphasise the need for integrated studies with wide taxon sampling and multiple data sources to resolve complex phylogenetic questions.

Kiwa hirsuta Macpherson, Jones & Segonzac, 2005 Kiwa hirsuta Macpherson et al., 2005: 713, figs 3–8 (South East Pacific Rise, vent site area named Annie's Anthill, 2228 m). — Segonzac, 2006: 450, figs (no record). Type data: holotype, male, MNHN Ga 5310. Type locality: South East Pacific Rise, vent site area named Annie's Anthill, 37º46.49´S, 110º54.72´W, 2228 m.

Genus Kiwa Macpherson, Jones & Segonzac, 2005 Kiwa Macpherson et al., 2005: 712 (gender: feminine). Type species: Kiwa hirsuta Macpherson et al., 2005, by monotypy., Published as part of Baba, Keiji, Macpherson, Enrique, Poore, Gary C. B., Ahyong, Shane T., Bermudez, Adriana, Cabezas, Patricia, Lin, Chia-Wei, Nizinski, Martha, Rodrigues, Celso & Schnabel, Kareen E., 2008, Catalogue of squat lobsters of the world (Crustacea: Decapoda: Anomura-families Chirostylidae, Galatheidae and Kiwaidae), pp. 1-220 in Zootaxa 1905 (1) on page 182, DOI: 10.11646/zootaxa.1905.1.1, http://zenodo.org/record/5134587, {"references":["Macpherson, E., Jones, W. & Segonzac, M. (2005) A new squat lobster family of Galatheoidea (Crustacea, Decapoda, Anomura) from the hydrothermal vents of the Pacific-Antarctic Ridge. Zoosystema, 27, 709 - 723."]}

220 páginas, 5 figuras, 1 tabla., [EN] This adaptation text reproduces Anexo I of the dissertation “Results”: Sistemática e historia evolutiva de la Familia Galatheidae (Crustacea: Anomura) en el Pacífico Sur, of Patricia Cabezas (2010) http://hdl.handle.net/10261/134771, [ES] Este artículo es una adaptación del Anexo I de la tesis doctoral: Sistemática e historia evolutiva de la Familia Galatheidae (Crustacea: Anomura) en el Pacífico Sur, of Patricia Cabezas (2010) http://hdl.handle.net/10261/134771, Taxonomic and ecological interest in squat lobsters has grown considerably over the last two decades. A checklist of the 870 current valid species of squat lobsters of the world (families Chirostylidae, Galatheidae and Kiwaidae) is presented. The compilation includes the complete taxonomic synonymy and geographical distribution of each species plus type information (type locality, repository and registration number). The numbers of described species in the world’s major ocean basins are summarised.

Genus Kiwa n. gen. TYPE AND ONLY SPECIES. ��� Kiwa hirsuta n. sp. ETYMOLOGY. ��� The name refers to the goddess of the shellfish in the Polynesian mythology (Kiwa). The gender is feminine. DIAGNOSIS. ��� Characters as for the family., Published as part of Macpherson, Enrique, Jones, William & Segonzac, Michel, 2005, A new squat lobster family of Galatheoidea (Crustacea, Decapoda, Anomura) from the hydrothermal vents of the Pacific-Antarctic Ridge, pp. 709-723 in Zoosystema 27 (4) on page 713, DOI: 10.5281/zenodo.4689563

Family KIWAIDAE n. fam. TYPE GENUS. ��� Kiwa n. gen. ETYMOLOGY. ��� The name is derived from the type genus Kiwa n. gen. DESCRIPTION Body depressed, symmetrical. Carapace calcified, slightly convex, smooth. Rostrum well developed, triangular. Cervical grooves clearly distinct between gastric and anterior branchial regions and between anterior and posterior branchial regions; either side of mesogastric region with small sharply defined tip. Cardiac region small and depressed and separated from branchial regions by shallow grooves. Anterior branchial regions well delimited and separated by short median longitudinal groove; small W-shaped groove over this groove. Posterior branchial regions separated by median longitudinal groove. Intestinal region well circumscribed and separat- ed from branchial regions by distinct grooves. Posterior half of pterygostomian flap with two longitudinal and subparallel carina. Abdominal segments smooth, not folded against thorax; telson folded beneath preceding abdominal somite, with a median transverse suture and a longitudinal suture in the posterior half of telson; uropods spatulate. Epistome unarmed. Sternal plate between third maxillipeds (sternite 3) well developed, strongly produced anteriorly; sternal plate between fifth pereopods (sternite 8) absent. Eyes strongly reduced to small soft tissue, not calcified, movable, without pigment, inserted near antennulae. Antennal peduncle 5-segmented, without antennal scale; flagellum of moderate length. Dense long plumose setae mainly on sternum and ventral surface of pereopods. Third maxillipeds with coxae having distal border strongly produced and denticulate, and each tooth with corneous margin; crista dentata in proximal half of ischium; epipods absent. Chelipeds (pereopod 1) strong, subequal, and greatly elongate, corneous tip of movable finger fitting between two corneous tips of fixed finger; walking legs (pereopods 2-4) stout, with claw-like dactyli bearing dense corneous spinules along flexor margin. Fifth pereopod chelated, inserted below sternite 7, insertion not visible ventrally., Published as part of Macpherson, Enrique, Jones, William & Segonzac, Michel, 2005, A new squat lobster family of Galatheoidea (Crustacea, Decapoda, Anomura) from the hydrothermal vents of the Pacific-Antarctic Ridge, pp. 709-723 in Zoosystema 27 (4) on page 712, DOI: 10.5281/zenodo.4689563

15 páginas, 9 figuras., [EN]A new monotypic family, Kiwaidae n. fam., is proposed for Kiwa hirsuta n. gen., n. sp., new genus and new species collected in hydrothermal vents of the Pacific-Antarctic Ridge, south of Easter Island. The new family belongs to the superfamily Galatheoidea, having similarities with the family Chirostylidae, but with distinctive characters including carapace shape and ornamentation, insertion of fifth pereopod not visible and situated below sternal plastron, sternite between third maxillipeds large and strongly produced anteriorly; eyes strongly reduced, antennal scale absent and chelipeds and walking legs with dense mat of setae. Molecular data (18S rRNA) gene confirm the clear difference between anomuran families, placing the new taxa closer to the families Chirostylidae, Galatheidae and Porcellanidae than to Aeglidae., [FR]Une nouvelle famille de Galatheoidea (Crustacea, Decapoda, Anomura) des sources hydrothermales de la dorsale Pacifique-Antarctique. Une nouvelle famille monotypique, Kiwaidae n. fam., est proposée pour Kiwa hirsuta n. gen., n. sp., récolté sur les sites hydrothermaux de la dorsale Pacifique-Antarctique, au sud de l’Île de Pâques. La nouvelle famille appartient à la superfamille Galatheoidea et présente des similitudes avec la famille des Chirostylidae, mais s’en distingue nettement par la forme et l’ornementation de la carapace, la base des cinquièmes péréiopodes, située sous le plastron sternal, et non visible ventralement, le sternite situé entre les troisièmes maxillipèdes, de grande taille et fortement prolongé antérieurement, les yeux réduits, l’écaille antennaire absente, et la dense couverture de soies. Les données moléculaires (rRNA 18S) confirment la nette différence entre les familles d’anomoures, plaçant le nouveau taxon plus près des Chirostylidae, Galatheidae et Porcellanidae que des Aeglidae., The cruise PAR 5 was funded by grants from the US National Science Foundation to R. C. Vrijenhoek (OCE-0241613) and to C. L. Van Dover (OCE-0350554).

The high level classification of the Chirostyloidea Ortmann, 1892, is reviewed. Eumunididae Milne-Edwards & Bouvier, 1900, is resurrected for two genera formerly placed in the Chirostylidae Ortmann, 1892, Eumunida Smith, 1883, and Pseudomunida Haig, 1979, based on shared characteristics such as the dorsal carapace striation, presence of supraocular spines of the rostrum, dentition of the mandible, presence of an epipod and an annulated exopod flagellum of maxilliped 1. Three families are now included in the Chirostyloidea: Chirostylidae, Eumunididae and Kiwaidae. Diagnoses are provided for each family as well as a key to the families. The fossil record of the Chirostyloidea is discussed, with putative records of Eumunida in the fossil record referred to the galatheid genus Sadayoshia Baba, 1969.

The Southern Australian crustacean species Lomis hirta (Lomisoidea: Lomisidae) is a representative of one of the three anomuran taxa which obtained their crab-like habitus independently from each other. This process, the evolutionary transformation into a crab-like form, is termed carcinization. To shed light on the morphological changes which took place during carcinization and to investigate structural dependence (coherence) between external and internal morphological characters, we studied L. hirta and representatives of its putatively most closely related taxa, Aegla cholchol (Aegloidea: Aeglidae) and Kiwa puravida (Chirostyloidea: Kiwaidae). External and internal anatomy was studied using microcomputertomography and computer-aided 3D reconstruction. A. cholchol and K. puravida belong to equally exceptional lineages: Aegla is endemic to South America and lives in freshwater habitats; Kiwa is a deep sea dweller associated to chemosynthetic bacteria found in methane seeps or hydrothermal vents. On the basis of recent cladistic analyses we reconstruct the anatomical ground pattern of the squat lobster-like last common ancestor of the three taxa and trace the morphological transformations that affected inner and outer morphology in the recent forms. Our results show, among other things, that the pleon in Lomis underwent drastic modifications in the context of carcinization, including a reduction of the muscular portion leaving more room for the hepatopancreas and gonads, and a narrowing of the pleonal ganglia which became shifted anteriorly into the cephalothorax and attached to the cephalothoracic ganglion. We interpret these anatomical changes in Lomis to have come about because of the loss of the caridoid escape reaction, which in turn was a direct consequence of the evolution of a strongly bent pleon as part of the crab-like habitus, and of a hidden lifestyle.