Progress 04/01/00 to 01/31/04
Outputs This project had the following significant outcomes: 1. Established phylogenetic relationships among major groups of arthropods (insects, crustaceans, myriapods and arachnids). 2. Discovered a new method of propulsive leg extension (elastic recoil) in arachnids and compared it quantitatively to hydraulic leg extension. 3. Described the skeletomuscular anatomy of representative arthropods 4. Described a new species.
Impacts This study determined the phylogenetic relationships of arthropods that will clarify evolution of the locomotor apparatus and other aspects of arthropod biology. The discovery and quantification of a new form of joint extension (elastic recoil) in walking arthropods is important for biomechanics generally and the design of biomimetic robots.
Publications
- Regier, J.C. & J.W. Shultz. 2001. Elongation factor-2, a useful gene for arthropod phylogenetics. Molecular Phylogenetics and Evolution, 20: 136-148.
- Shultz, J.W. & J.C. Regier. 2001. Phylogenetic analysis of Phalangida (Arachnida, Opiliones) using two nuclear protein-encoding genes supports monophyly of Palpatores. Journal of Arachnology, 29: 189-200.
- Shultz, J.W. 2001. Gross muscular anatomy of Limulus polyphemus (Chelicerata, Xiphosura) and its bearing on evolution in the Arachnida. Journal of Arachnology, 29: 283-303.
- Sensenig, A. & J.W. Shultz. 2003. Mechanics of cuticular elastic energy storage in leg joints lacking extensor muscles in arachnids. Journal of Experimental Biology, 206: 771-784.
- Shultz, J.W. & T. Cekalovic. 2003. A new species of Austropsopilio (Opiliones, Caddoidea, Caddidae) from South America. Journal of Arachnology, 31: 20-27.
- Sensenig, A. & J.W. Shultz. 2004. Mechanics of elastic extension in the pedipalpal joints of scorpions and solifuges (Arachnida: Scorpiones, Solifugae). Journal of Arachnology
- Mallatt, J., J.R. Garey & J.W. Shultz. 2004. Ecdysozoan phylogeny and Bayesian inference: first use of nearly complete 28S and 18S rRNA gene sequences to classify the arthropods and their kin. Molecular Phylogenetics and Evolution.
- Regier, J.C., J.W. Shultz, R.E. Kambic & D.R. Nelson. 2004. Robust support for tardigrade clades and their ages from three protein-coding nuclear genes. Invertebrate Biology.
- Regier, J.C., J.W. Shultz & R.E. Kambic. 2004. Phylogeny of basal hexapod lineages and estimates of divergence times. Annals of the Entomological Society of America
- Shultz, J.W. 2000. Skeletomuscular anatomy of the harvestman Leiobunum aldrichi (Weed, 1893)(Arachnida: Opiliones) and its evolutionary significance. Zoological Journal of the Linnean Society, 128: 401-438.
- Shultz, J.W. & J.C. Regier. 2000. Phylogenetic analysis of two nuclear protein-encoding genes in arthropods supports a crustacean-hexapod clade. Proceedings of the Royal Society of London B, 267: 1011-1019
- Regier, J.C. & J.W. Shultz. 2001. A phylogenetic analysis of Myriapoda (Arthropoda) using two nuclear protein-encoding genes. Zoological Journal of the Linnean Society, 130: 213-234.
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Progress 01/01/02 to 12/31/02
Outputs Molecule- and morphology-based phylogenetic analyses of major arthropod groups have been completed and are continuing. The resulting phylogenetic trees are to be used as a historical framework for reconstructing evolution of the locomotor apparatus. Functional analyses of elastic storage and hydraulic mechanisms of joints of arthropod legs and pedipalps have been completed.
Impacts The work has discovered elastic joint mechanisms that are extremely resilient (up to 90% of input energy is recovered during elastic recoil)and powerful (capable of generating propulsive thrust without aid from hydraulics). This is the first time that an elastic mechanism has been documented in arthropods that are used during walking; it was previously known that such mechanisms were important in jumping and flying.
Publications
- Shultz, J.W. & T. Cekalovic. 2002. A new species of Austropsopilio (Opiliones, Caddoidea, Caddidae) from South America. Journal of Arachnology, 30.
- Sensenig, A. & J.W. Shultz. 2003. Mechanics of cuticular elastic energy storage in leg joints lacking extensor muscles in arachnids. Journal of Experimental Biology. In press.
- Sensenig, A.T. & J.W. Shultz. 2003. Elastic energy storage in the pedipalpal joints of scorpions and sun-spiders (Arachnida: Scorpiones, Solifugae). Journal of Arachnology, Submitted
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Progress 01/01/01 to 12/31/01
Outputs Molecule- and morphology-based phylogenetic analyses of major arthropod groups have been completed and are continuing. The resulting phylogenetic trees are to be used as a historical framework for reconstructing evolution of the locomotor apparatus. Functional analyses of elastic storage mechanisms of joints of arthropod legs have been completed for scorpions, opilions and solifuges. Progress has been made on spiders and whipscorpions.
Impacts The important role of elastic storage mechanisms in walking legs of arthropods was unexpected. Current theory predicts energetically efficient elastic energy storage only in large animals that can load elastic elements inertially. The existence of elastic storage in arthropods requires re-evaluation of basic locomotor principles.
Publications
- Regier, J.C. & J.W. Shultz. 2001. A phylogenetic analysis of Myriapoda (Arthropoda) using two nuclear protein-encoding genes. Zoological Journal of the Linnean Society, 130: 213-234.
- Regier, J.C. & J.W. Shultz. 2001. Elongation factor-2, a useful gene for arthropod phylogenetics. Molecular Phylogenetics and Evolution, 20: 136-148.
- Shultz, J.W. & J.C. Regier. 2001. Phylogenetic analysis of Phalangida (Arachnida, Opiliones) using two nuclear protein-encoding genes supports monophyly of Palpatores. Journal of Arachnology, 29: 189-200.
- Shultz, J.W. 2001. Gross muscular anatomy of Limulus polyphemus (Chelicerata, Xiphosura) and its bearing on evolution in the Arachnida. Journal of Arachnology,in press
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