Loxothylacus panopaei

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Classification

Kingdom; Animalia, Phylum; Arthropoda, Class; Maxillopoda, Order; Kentrogonida, Family; Sacculinidae, Genus; Loxothylacus,

Species

Species; panopaei Description and Significance Describe the appearance, habitat, etc. of the organism, and why you think it is important. Genome Structure Describe the size and content of the genome. How many chromosomes? Circular or linear? Other interesting features? What is known about its sequence? The adult version of Loxothylacus panopaei consists of a kidney shaped mass of yellow-orange tissue attached to the third abdominal segment of a mud crab by a stalk. It has a barnacle like ancestry. Cell Structure, Metabolism and Life Cycle Interesting features of cell structure; how it gains energy; what important molecules it produces. Ecology and Pathogenesis Nauplius and cypris larvae are morphologically distinct for the two sexes; Female: The female cypris settles in the branchial chamber of a recently molted crab. Inside the cypris shell, the kentrogon stage, develops. This stage is marked by a dart-shaped injection stylet which penetrates the crab's cuticle. Through this stylet, a motile vermiform body, composed of embryonic cells, covered in a fibrous acellular sheath, is injected into the crab's hemolymph. The injection process takes about two minutes, and the vermiform body remains intact and motile for 8-16 hours, before it breaks up into around 25 separate, motile, embryonic cells. Each cell has the potential to form a complete parasite, but normally only one succeeds. This cell begins a phase of rapid proliferation which results in the growth of the interna, a mass of rootlike tissue which pervades the visceral mass of the crab. As the interna matures, growth of the externa, a sac protruding from the abdomen of the crab begins. This sac resembles an egg mass, but is found on both male and female crabs. Male: Male cyprids are attracted to unmated externae and settle around the aperture of the externa. These cyprids inject a distinct life stage composed of undifferentiated cells, the trichogon, into the mantle cavity of the externa. These cells move into receptacles in the mantle cavity, where they develop into two testicular masses, connected to the brood chamber by a short vas deferens. Settlement of the male triggers rapid growth and final maturation of the externa, which culminates in the production and release of nauplii. Broods are released every 5-6 days. While one externa per crab is typical, 10% of crabs had multiple externae, usually 2-3, but sometimes as many as six. References [Sample reference] Takai, K., Sugai, A., Itoh, T., and Horikoshi, K. "Palaeococcus ferrophilus gen. nov., sp. nov., a barophilic, hyperthermophilic archaeon from a deep-sea hydrothermal vent chimney". International Journal of Systematic and Evolutionary Microbiology. 2000. Volume 50. p. 489-500. Author Page authored by Aalysah McClease, student of Prof. Bradley Tolar at UNC Wilmington.