Further, we consider the different predators that rely on Themisto for a large fraction of their diet, demonstrating their major importance for higher trophic levels such as fish, seabirds and mammals. Gene tree discordance, phylogenetic inference. B, Heled, J., Drummond, A.J., 2010. This species was isolated from the Thermaikos Gulf in Greece, and its description is largely based on observations of cultured material. The red and the black: bioluminescence and the color of animals. Overall, morphology based recon-, structions among and within the four major groups of Amphipoda, suggests that convergent evolution may be playing a central role in, The Amphipoda are generally organized into the largely benthic, taxa, the Gammaridea, Caprellidea, Ingolfiellidea, and the pelagic. Metalycaea globosa Stephensen, 1925, sometimes included in the Oxycephalidae, is confirmed to be a junior synonym of Lycaea serrata Claus, 1879. Zeidler, W., 1999. Review of the hyperiidean amphipod genus. Despite strong support of basal, nodes in the concatenated tree, disagreements between the species, tree methods indicate that the current dataset does not contain en-, ough information to confidently reconstruct these older evolution-, ary events. Further, our results indicated the necessity of a revision of the family-level systematics. In contrast to deep water taxa, the Physocephalata typi-, cally display varying degrees of transparency, possess large heads. Even its gut (the bubble-like blue outline you can see in the picture) is see-through. MDC analysis based on Bayesian, input trees placed the Vibilioidea as sister group to the Platysceloi-, dea consistent with the results obtained from both concatenated, grouped the Vibilioidea with the Phronimoidea (, the two different MDC analytical methods rearrangements among, terminal taxa within the Oxycephalidae was observed. Specimens of hyperiid amphipods were identified using, sp., were collected and sequences were used for out-, ), 18S, and 28S ribosomal genes were completed using primers, . Additional sam-, pling among the Lanceolidae is certainly warranted given our re-, sults. On the anatomy of Cystisoma (Amphipoda: Hyperiidea). The family Brachyscelidae is restricted to the genus Brachyscelusbecause Thamneus, previously included in Brachyscelidae, has a number of characters that differ considerably from any other genus of Hyperiidea and it is therefore placed in a family of its own, Thamneidae fam. lampreys and hagfishes. Liu, L., 2008. Here we present the first multi-locus molecular phylogenetic assessment of relationships among the hyperiid amphipods. Monitoring for the presence of the endangered Pygmy Madtom, and delineating th. 1–14. Given the observations of gene tree heterogeneity across, nuclear loci a species tree approach to the phylogenetic recon-, struction of hyperiid relationships was warranted (, Results from our MDC analyses based on both Bayesian and ML, input trees recovered the same four major clades observed in the, disagreed on the relationships between the three clades compris-, ing the infraorder Physocephalata. Structural simplifications associated with abdom-, ). Molecular phylogenetic evidence for the independent evolutionary origin of... Incongruence between molecular phylogeny and morphological classification in amphipod crustaceans: A... Arthropod fossil data increase congruence of morphological and molecular phylogenies. The white arrowhead indicates the, feeding on the inner surface of the ‘barrel’. In northern parts of the Southern Ocean, Themisto are so prevalent that they are considered to take on the role that Antarctic krill play further south. Species-tree estimates based on Minimize Deep Coalescent (MDC) criterion as performed by Phylonet. Program Distributed by the Author, The associations of Amphipoda Hyperiidea with gelatinous zooplankton. Here we present the first multi-locus molec-, ular phylogenetic assessment of relationships among the hyperiid amphipods. Cell Develop. 14, 346–370. Inferring phylogeny despite incomplete lineage, Maddison, W.P., Maddison, D.R., 2010. Molecular Phylogenetics and Evolution 67 (2013) 28–37, journal homepage: www.elsevier.com/locate/ympev, homoplasious morphological features may be masking true phylo-, genetic relationships among extant hyperiid amphipods. (m) Anterioventral view of a female, elongated dorsally directed crystalline cones. The orange arrowhead marks the position of the anterior-posteriorly elongated retina. Scientists think this could be because the animals need to see possible prey or mates that would be found overhead. Hyperiids of the genus Themisto, comprising seven distinct species, are key players in temperate and cold-water pelagic ecosystems where they reach enormous levels of biomass. Bayesian inference of species trees from multilocus, Huang, H., Knowles, L.L., 2009. Zootaxa 2000. A review of the families and genera of the hyperiidean amphipod. Biological inspiration, schematic view, and practical sample of an optically transparent microwave invisibility cloak. The validity of these morphological characters was assessed by resolving phylogenetic relationships using nuclear 28S rRNA and mitochondrial cytochrome oxidase subunit I sequences. Protein, coding datasets (COI and H3) were further partitioned by codon, site for a total of nine partitions. The Phro-. J. Zool. You do not currently have access to this article. ecological roles in pelagic food webs. Underwater observations of blue-water plankton: logistics, techniques, and safety procedures for divers at sea. 57, 876–. Our, MDC analyses supported the existence of the same four major, clades identified in the concatenation tree (, among trees produced under different phylogenetic methods did, occur at basal nodes, indicating that relationships among the four, major clades are still unresolved. Comp. Here portions of the, are extraordinarily hypertrophied dominating nearly the entire head capsule. We present the first multi-locus molecular phylogenetic assessment of the Themisto in the Northern Hemisphere. Enjoy the photos of the animals she’s researching in this slideshow, and read more about her research on the Smithsonian's Department of Invertebrate Zoology No Bones blog. In northern latitudes, free-swimming hyperiids belonging to the genus Themisto (Guérin, 1825) are important components of marine ecosystems in term of abundance and biomass, but little is known about their genetic relationships. Moreover, morphological changes associated with host switching have not yet been studied. The green arrow highlights the greatly reduced first antennae of females. Among other fields, MBARI’s science has benefited from applying novel methodologies in molecular biology and genetics, imaging systems, and in situ observations. The majority of zooplankton By contrast, due to their affinity for cold/oxygenated water and absence of pre-Cenozoic fossils, we hypothesized that the ecological divergence of amphipods arose throughout the cool Late Mesozoic/Cenozoic. The white arrow marks the location of the foregut and, . These results illustrate exactly why arthropod compound eye evolution has remained controversial, because one of two seemingly very unlikely evolutionary histories must be true. Zool. under mixed models. Fine structure of the compound eyes of the midwater amphipod. Either compound eyes with detailed similarities evolved multiple times in different arthropod groups or compound eyes have been lost in a seemingly inordinate number of arthropod lineages. Based on our multilocus phylogeny, major rearrangements to existing taxonomic groupings of hyperiid amphipods are warranted. They typically live at depths of 100-400m on siphonophores, colonies of animals related to Portuguese Man-o-war that are distant relatives of jellyfish. This female hyperiid (Phronima sedentaria) is surrounded by her young, residing in the hollowed out barrel-shaped body cavity of a salp. The Hyperiidea are a suborder of amphipods, small aquatic crustaceans. Both Bayesian and ML analyses of concatenated datasets of-, Huang and Knowles, 2009; Liu and Edwards, 2009, Degnan and Rosenberg, 2009; Knowles and Kubatko, 2010. The family Platyscelidae is restricted to four genera, Platyscelus, Paratyphis, Hemityphis and Tetrathyrus; Amphithyrus having been removed to the new family Amphithyridae. This study presents the first molecular phylogenetic analysis based on a representative subset of the Antarctic species belonging to different, The relationships of major arthropod clades have long been contentious, but refinements in molecular phylogenetics underpin an emerging consensus. Evol. Some controversy exists as to the number of families in the Hyperiidea, being given as between 20 and 23 depending on whether groups like the Thaumatopsidae are considered distinct or not. Physical vouchers, exist for specimens and are housed at the University of Miami, (Coral Gables, FL) and the Smithsonian NMNH (Washington, DC), hyperiid taxa included in this analysis were not identified to spe-, cies level. Biol. All figure content in this area was uploaded by William E Browne, All content in this area was uploaded by William E Browne on Mar 06, 2018, Molecular phylogenetic evidence for the reorganization of the Hyperiid, amphipods, a diverse group of pelagic crustaceans, University of Miami, Cox Science Center, 1301 Memorial Drive, Miami, FL, 33146, United States, Monterey Bay Aquarium Research Institute, 7700 Sandholdt Road, Moss Landing, CA, 95039, United States, Within the crustaceans, the Amphipoda rank as one of the most speciose extant orders. Mol. Figure 1 shows a generalized hyperiid with the principal parts labeled. Within, monophyletic clades; the Platysceloidea, Vibilioidea, and Phronimoidea. Alignment of datasets for both the, 18S and 28S ribosomal genes resulted in a large number of indels, and parsimony informative sites, and best fitting model are sum-, Gene trees recovered from ML and Bayesian analysis of concat-, enated datasets have nearly identical topologies (Bayesian tree, with corresponding ML bootstrap support values is shown in, clades with 100% posterior probability/bootstrap support: Physos-, omata, Phrominoidea, Platysceloidea, and Vibilioidea. Each of their two large eyes has an upward-looking zone and a downward-looking zone. 46, 523–536. Genera are diagnosed using the taxonomic database program DELTA (Dalwitz et al. In particular characters associated with feed-, ing morphologies have been heavily used in existing hyperiid sys-. Traditional morphological analyses of hyperiids have generally, been more focused on characters useful for systematic classifica-, tion schemes and less focused on characters useful for determining, phylogenetic groups. A classification is proposed for the order Amphipoda. These eyes look upwards and are uniquely adapted to look for silhouettes of other animals illuminated by the dim light that filters down from the surface of the ocean. They range in size from very tiny to more than 7 inches long, and are found at all depths of the ocean from the surface to the deep sea. Oceanogr. evidence for the existence of a Tardigrada + Arthropoda clade. The anatomy of three species of hyperiid amphipods of the genus Cystisoma is discussed. Maddison, W.P., Knowles, L.L., 2006. In the Atlantic, the western edge of the Gulf Stream, the, Caribbean, and the Weddell Sea were sampled. The RAxML software accommo-, dates the GTR model of nucleotide substitution with the additional, able sites (I). 0718975, OCE-1125396), the David and Lucile Packard Foundation, and startup funds from University of Miami College of Arts and Sci-, ences. In addition, we also explored the utility of species-tree methods for reconstructing, deep evolutionary histories using the Minimize Deep Coalescence (MDC) approach. Huelsenbeck, J.P., Ronquist, F., 2001. In contrast to the, Mimonectidae branch basal to the Scinidae, we discovered sup-, polyphyletic. The body form is quite varied. It is most likely looking for signs of bioluminescence—bright green and blue flashes of light made by animals—that could signal that food or a predator is nearby. Clustal alignments of the COI dataset resulted in 8 indels, ).