@article{weiss1890excretory,
    author = "Weiss, F. Ernest",
    title = "Excretory Tubules in Amphioxus lauceolatus",
    year = "1890",
    journal = "Journal of Cell Science",
    abstract = "In the spring of last year, through the kind permission of the British Association for the Advancement of Science, I had the privilege of occupying the table which the Association supports at the Zoological Station in Naples. By the admirable arrangements made at this station I was able to have a constant and unlimited supply of living specimens of Amphioxus lanceolatus, and thought this a good opportunity to undertake some experiments with a view to ascertaining whether the curious patches of modified epithelial cells on the ventral wall of the atrium of Amphioxus had any excretory function, as Johannes Müller (1) had held probable; and whether also the atrio-cœlomic funnels first described by Professor Ray Lankester (2) in 1874, and again more recently (3), had any such function.",
    url = "https://doi.org/10.1242/jcs.s2-31.124.489",
    doi = "10.1242/jcs.s2-31.124.489",
    number = "124",
    openalex = "W2598117956",
    pages = "489-498",
    volume = "S2-31"
}

@article{patten1898the,
    author = "PATTEN, WILLIAM",
    title = "THE STRUCTURE AND ORIGIN OF THE EXCRETORY ORGANS OF LIMULUS",
    year = "1898",
    journal = "Zoological Bulletin",
    url = "https://doi.org/10.2307/1535480",
    doi = "10.2307/1535480",
    number = "6",
    openalex = "W2525703570",
    pages = "311-313",
    volume = "1"
}

@article{doi101098rspl19010118,
    author = "Goodrich, Edwin S.",
    title = "On the excretory organs of Amphioxus",
    year = "1902",
    journal = "Proceedings of the Royal Society of London",
    abstract = "Abstract Some years ago, in 1890, Weiss and Boveri discovered excretory tubules in the pharyngeal region of Amphioxus. Soon after Boveri published a detailed description and figures of these segmental kidneys. According to Boveri, each organ consists of a narrow ciliated tubule opening on the one hand into the atrium at the top of a secondary gill-bar, and on the other hand into the dorsal cœlom by one or more funnels. Groups of peculiar cells, called “fadenzellen,” are spread round each funnel, attached to the cœlomic wall. These cells send each a long fine process passing towards the lip of the funnel across its opening.",
    url = "https://doi.org/10.1098/rspl.1901.0118",
    doi = "10.1098/rspl.1901.0118",
    openalex = "W2082651147"
}

@article{goodrich1902on,
    author = "Goodrich, Edwin S.",
    title = "On the Structure of the Excretory Organs of Amphioxus",
    year = "1902",
    journal = "Journal of Cell Science",
    abstract = "The excretory organs of Amphioxus were independently discovered by Weiss and Boveri in the year 1890 (1 and 13). Weiss described a series of small tubules regularly distributed at the top of each secondary tongue-bar throughout the region of the pharynx. The tubules are situated, for the most part, in the wall separating the dorsal cœlom from the atrial cavity; they lie, therefore, between the cœlomic and the atrial epithelium, generally separated from the latter by a network of fine blood-vessels. These kidney tubules open into the atrium by a pore just opposite the dorsal end of the secondary gill-bar. Weiss suspected the presence of an internal opening, but could not find it. The physiological significance of these organs he established by means of feeding experiments with carmine and other colouring matters.",
    url = "https://doi.org/10.1242/jcs.s2-45.180.493",
    doi = "10.1242/jcs.s2-45.180.493",
    number = "180",
    openalex = "W4386146192",
    pages = "493-501",
    volume = "S2-45"
}

@article{goodrich1902on1,
    author = "Goodrich, E. S",
    title = "On the structure of the execretory organs of Amphioxus, Part 1",
    year = "1902",
    journal = "Quarterly Journal of Microscopical Science, v. 45, p. 493-501",
    note = "talkorigins\_source = {true}; raw\_reference = {Goodrich, E. S., 1902, On the structure of the execretory organs of Amphioxus, Part 1: Quarterly Journal of Microscopical Science, v. 45, p. 493-501.}"
}

@article{sgoodrich1909on,
    author = "S. Goodrich, Edwin",
    title = "On the Structure of the Excretory Organs of Amphioxus",
    year = "1909",
    journal = "Journal of Cell Science",
    url = "https://doi.org/10.1242/jcs.s2-54.214.185",
    doi = "10.1242/jcs.s2-54.214.185",
    number = "214",
    openalex = "W2752689176",
    pages = "185-205",
    volume = "S2-54",
    references = "doi101242jcss231123445, doi101242jcss232126183, doi101242jcss247185103, goodrich1902on, macbride1898the"
}

@incollection{potts1964excretory,
    author = "POTTS, W.T.W. and PARRY, GWYNETH",
    title = "EXCRETORY ORGANS",
    year = "1964",
    booktitle = "Osmotic and Ionic Regulation in Animals",
    url = "https://doi.org/10.1016/b978-0-08-013598-4.50007-9",
    doi = "10.1016/b978-0-08-013598-4.50007-9",
    openalex = "W3022280052",
    pages = "44-88"
}

@article{nakao1965the,
    author = "Nakao, Taisuke",
    title = "The excretory organ of Amphioxus (Branchiostoma) belcheri",
    year = "1965",
    journal = "Journal of Ultrastructure Research",
    url = "https://doi.org/10.1016/s0022-5320(65)80002-8",
    doi = "10.1016/s0022-5320(65)80002-8",
    number = "1-2",
    openalex = "W1974198500",
    pages = "1-12",
    volume = "12",
    references = "doi101016s002253206180018x, doi101083jcb171208, doi101083jcb35827, doi101083jcb92409"
}

@article{doi1023073276582,
    author = "Morseth, David J.",
    title = "Fine Structure of the Hydatid Cyst and Protoscolex of Echinococcus granulosus",
    year = "1967",
    journal = "Journal of Parasitology",
    abstract = "The fine structure of various parts of the hydatid cysts and the enclosed protoscolex is described. The contents of the brood capsule are PAS-positive following extraction treatment with amylase. This material is made up of fine irregularly arranged filaments, and remains as a coating over the posterior aspect of the protoscolex after its removal from the brood capsule. It has completely disappeared after 42 days in vitro. The posterior aspect of the protoscolex is with knoblike projections which are probably undeveloped tegumental projections. After 42 days culture in vitro this area has fully developed tegumental projections. Multinucleation of tegumental cells is common in the protoscolices cultured for 42 days in vitro. The various organ systems are described and compared with similar structures reported for tapeworms and other invertebrates. Although the teguments of several species of adult tapeworms have been examined by electron microscopy, the fine structure of the intermediate stages in their life history has been neglected. Goldschmidt (1900) was apparently the first to describe the spines on the body surface of developing protoscolices of Echinococcus granulosus, and subsequently Coutelen (1927) described the surface distribution of these spines in more detail. These authors, though limited to light microscopy, stated that the spines were seen only under ideal conditions with an oil immersion objective. More recent workers have made similar observations on the cystic stage of several taeniid tapeworms (Crusz, 1948; Voge, 1962, 1963). Waitz (1961) in describing the ultrastructure of the cystic stage of Hydatigera taeniaeformis mentions the presence of microvilli on the body surface. Larsh et al. (1965) in a study on the histopathology of infections in mice with the cystic stage of Multiceps serialis include an electron micrograph of a portion of cyst wall (their figure 7). Although a discussion of the fine structure is outside the scope of their paper, it is significant that their illustration clearly shows surface projections, vesicles within the tegument, and dark structures which may be mitochondria. Siddiqui (1963) examined the tegument of cysticerci of Taenia saginata, T. hydatigena, and T. pisiformis and noted that all three species were covered with hair-like processes. In an account of the ultrastructure of the Received for publication 27 July 1966. cystic stage of M. serialis, Race et al. (1965), reported that the subcuticular canals connect the cuticle with the parenchyma. Marzullo et al. (1957) reported the presence of mucopolysaccharides in the cyst of E. granulosus. Kilejian et al. (1961) demonstrated that the brood capsule contents are PAS-positive after saliva treatment. The electron microscopic appearance of this material has not previously been demonstrated. The investigation reported in this paper is an extension of previous work on the fine structure of adult taeniid tapeworms (Morseth, 1965, 1966) and especially that of E. granulosus. MATERIALS AND METHODS",
    url = "https://doi.org/10.2307/3276582",
    doi = "10.2307/3276582",
    openalex = "W2319056585"
}

@article{doi101002jmor1051390403,
    author = "Möller, Peter C. and Philpott, Charles W.",
    title = "The circulatory system of Amphioxus (Branchiostoma floridae) I. Morphology of the major vessels of the pharyngeal area",
    year = "1973",
    journal = "Journal of Morphology",
    abstract = "Abstract In order to clarify the morphology of the circulatory system of amphioxus the blood vessels were investigated using modern techniques of light and electron microscopy. The pattern of circulation in amphioxus is forward ventrally and backwards dorsally. In addition, circulating corpuscles, usually associated with the blood of higher chordates, are absent. The circulatory system of amphioxus consists of well defined contractile vessels and vascular spaces or sinuses within a connective tissue matrix. The contractile vessels have a discontinuous endothelial lining resting on a basal lamina and are enclosed by a simple layer of contractile myoepithelial cells. Discontinuous endothelial linings occur throughout the vascular tree, including major and minor afferent and efferent vessels and blood sinuses. This is in contrast to higher animals where the endothelium forms a more or less continuous lining along the inner surface of the boundary layer. It is suggested that the endothelial cells of amphioxus, like the endothelial cells in capillaries of higher chordates, most likely play a role in the physiology of the circulatory system by removing residues of filtration from the basal lamina, thereby facilitating an exchange of materials to and from the surrounding tissues.",
    url = "https://doi.org/10.1002/jmor.1051390403",
    doi = "10.1002/jmor.1051390403",
    openalex = "W2143598529",
    references = "doi10100797836429105483, doi101083jcb171208, doi101083jcb202313, doi101083jcb231101, doi101083jcb351213, doi101083jcb372244, doi101083jcb372277, doi101083jcb44475, doi101083jcb92409, doi10310910520296009114754, doi105962bhltitle6856"
}

@article{moller1974fine,
    author = "Moller, PeterC. and Ellis, RichardA.",
    title = "Fine structure of the excretory system of Amphioxus (Branchiostoma floridae) and its response to osmotic stress",
    year = "1974",
    journal = "Cell and Tissue Research",
    url = "https://doi.org/10.1007/bf00224314",
    doi = "10.1007/bf00224314",
    number = "1",
    openalex = "W2083401012",
    volume = "148",
    references = "doi101002jmor1051390403, doi101007bf00336662, doi101016s0022532069900331, doi101083jcb171208, doi101083jcb202313, doi10117711114, doi101242jeb313424, doi10310910520296009114754, doi105962bhltitle55924, nakao1965the, openalexw2047767613"
}

@article{doi101098rstb19860056,
    author = "White, JG and Southgate, Eileen and Thomson, J. Nichol and Brenner, Sydney",
    title = "The structure of the nervous system of the nematode Caenorhabditis elegans",
    year = "1986",
    journal = "Philosophical transactions of the Royal Society of London. Series B, Biological sciences",
    abstract = "The structure and connectivity of the nervous system of the nematode Caenorhabditis elegans has been deduced from reconstructions of electron micrographs of serial sections. The hermaphrodite nervous system has a total complement of 302 neurons, which are arranged in an essentially invariant structure. Neurons with similar morphologies and connectivities have been grouped together into classes; there are 118 such classes. Neurons have simple morphologies with few, if any, branches. Processes from neurons run in defined positions within bundles of parallel processes, synaptic connections being made en passant. Process bundles are arranged longitudinally and circumferentially and are often adjacent to ridges of hypodermis. Neurons are generally highly locally connected, making synaptic connections with many of their neighbours. Muscle cells have arms that run out to process bundles containing motoneuron axons. Here they receive their synaptic input in defined regions along the surface of the bundles, where motoneuron axons reside. Most of the morphologically identifiable synaptic connections in a typical animal are described. These consist of about 5000 chemical synapses, 2000 neuromuscular junctions and 600 gap junctions.",
    url = "https://doi.org/10.1098/rstb.1986.0056",
    doi = "10.1098/rstb.1986.0056",
    openalex = "W2160938187",
    references = "doi101083jcb171208"
}

@incollection{seitz1987excretory,
    author = "Seitz, Karl-August",
    title = "Excretory Organs",
    year = "1987",
    booktitle = "Ecophysiology of Spiders",
    url = "https://doi.org/10.1007/978-3-642-71552-5\_17",
    doi = "10.1007/978-3-642-71552-5\_17",
    openalex = "W4236359815",
    pages = "239-248"
}

@incollection{warburg1993excretory,
    author = "Warburg, Michael R.",
    title = "Excretory Organs and Excretion",
    year = "1993",
    booktitle = "Evolutionary Biology of Land Isopods",
    url = "https://doi.org/10.1007/978-3-662-21889-1\_5",
    doi = "10.1007/978-3-662-21889-1\_5",
    openalex = "W2130884168",
    pages = "32-35"
}

@article{doi101111j146363951998tb01150x,
    author = "Stach, Thomas and Eisler, Klaus",
    title = "The Ontogeny of the Nephridial System of the Larval Amphioxus (Branchiostoma lanceolatum)",
    year = "1998",
    journal = "Acta Zoologica",
    abstract = "Abstract Three developmental stages of Branchiostoma lanceolatum were examined by means of transmission electron microscopy. The development of the protonephridium‐like cyrtopodocyte from nearly undifferentiated (ento‐) mesodermal cells is demonstrated. The ultrastructure of Hatschek's nephridium in an early larval stage is described. The existence of a second filtralional barrier around the rod‐like microvilli of the cyrtopodocytes was confirmed. The mesodermal nephridium drains via an excretory canal which is possibly of ectodermal origin into the oral cavity. Cytotic vesicles in the canal cells suggest that the organ is functional in the earliest larval stages. The phylogenetic interpretation of the cyrtopodocyte is clarified as an autapomorphy of the acraniates derived from a podocyte with an apical cilium. The whole system is comparable to the pronephros of craniates and therefore represents a modified metanephridium.",
    url = "https://doi.org/10.1111/j.1463-6395.1998.tb01150.x",
    doi = "10.1111/j.1463-6395.1998.tb01150.x",
    openalex = "W2009983771",
    references = "doi101016s002253206180018x, doi101093icb344542, doi101111j109600311986tb00462x, doi101111j143904691992tb00388x, doi101111j1469185x1988tb00631x, doi101126science7089565, doi101242jcss286342113, doi1023071541916, goodrich1902on, nakao1965the, openalexw211829355, openalexw2397787987, openalexw2400122185"
}

@article{doi101159000079744,
    author = "Lacalli, Thurston C.",
    title = "Sensory Systems in Amphioxus: A Window on the Ancestral Chordate Condition",
    year = "2004",
    journal = "Brain Behavior and Evolution",
    abstract = "Amphioxus has an assortment of cells and organs for sensing light and mechanical stimuli. Vertebrate counterparts of these structures are not always apparent, and a strong case can be made for homology in only a few instances. For example, amphioxus has anatomically simple but plausible homologs of both the pineal and paired eyes of vertebrates. Placodal and neural crest derivatives are, however, more problematic: the evidence for an olfactory system in amphioxus is only circumstantial and, despite the variety of secondary sensory cell types that occur on the body surface in amphioxus, none are obvious homologs of vertebrate taste buds, neuromasts or acoustic hair cells. A useful perspective can nevertheless be gained by examining differences in amphioxus and vertebrate development, specifically how each specifies and positions sensory precursors, controls their proliferation, and deploys them through the body. The much larger size of vertebrate embryos and the need to cope developmentally with increased scale and cell numbers may account for some key vertebrate innovations, including placodes and neural crest. The presence or absence of specific structural adaptations, like the latter, is therefore less useful for judging homology between amphioxus and vertebrates than shared features of specific cell types. It is also clear that the duration of embryogenesis in vertebrates has been significantly extended in comparison with ancestral chordates so as to incorporate events that would originally have occurred during the post-embryonic growth period, including events of neurogenesis. Consequently, no scenario for the origin of vertebrates can be considered complete unless it deals explicitly with the whole of the life history and changes to it.",
    url = "https://doi.org/10.1159/000079744",
    doi = "10.1159/000079744",
    openalex = "W1974192701",
    references = "bone1961the, doi101046j14636395200200097x, doi101046j1525142x200202021x, doi101086413055, doi101098rspb19980385, doi101098rstb19940059, doi101098rstb19960022, doi101111j146363951995tb00986x, doi101111j1469185x1989tb00471x, doi101111j146979981978tb03931x, doi101139z04163, doi101159000147529, doi101242dev125142701, doi101242dev12561113, stokes1995ciliary"
}

@article{doi101139z04163,
    author = "Wicht, Helmut and Lacalli, Thurston C.",
    title = "The nervous system of amphioxus: structure, development, and evolutionary significance",
    year = "2005",
    journal = "Canadian Journal of Zoology",
    abstract = "Amphioxus neuroanatomy is important not just in its own right but also for the insights it provides regarding the evolutionary origin and basic organization of the vertebrate nervous system. This review summarizes the overall layout of the central nervous system (CNS), peripheral nerves, and nerve plexuses in amphioxus, and what is currently known of their histology and cell types, with special attention to new information on the anterior nerve cord. The intercalated region (IR) is of special functional and evolutionary interest. It extends caudally to the end of somite 4, traditionally considered the limit of the brain-like region of the amphioxus CNS, and is notable for the presence of a number of migrated cell groups. Unlike most other neurons in the cord, these migrated cells detach from the ventricular lumen and move into the adjacent neuropile, much as developing neurons do in vertebrates. The larval nervous system is also considered, as there is a wealth of new data on the organization and cell types of the anterior nerve cord in young larvae, based on detailed electron microscopical analyses and nerve tracing studies, and an emerging consensus regarding how this region relates to the vertebrate brain. Much less is known about the intervening period of the life history, i.e., the period between the young larva and the adult, but a great deal of neural development must occur during this time to generate a fully mature nervous system. It is especially interesting that the vertebrate counterparts of at least some postembryonic events of amphioxus neurogenesis occur, in vertebrates, in the embryo. The implication is that the whole of the postembryonic phase of neural development in amphioxus needs to be considered when making phylogenetic comparisons. Yet this is a period about which almost nothing is known. Considering this, plus the number of new molecular and immunocytochemical techniques now available to researchers, there is no shortage of worthwhile research topics using amphioxus, of whatever stage, as a subject.",
    url = "https://doi.org/10.1139/z04-163",
    doi = "10.1139/z04-163",
    openalex = "W2092757339",
    references = "anadn1998distribution, bone1959the, bone1961the, castro2003distribution, dogiel1903das, doi101002cne901150105, doi101002jmor1050540103, doi1010079783642182624, doi101007bf00348527, doi101007bf02028391, doi101016jydbio200604457, doi101016s0022532062800070, doi101098rstb19940059, doi101098rstb19960022, doi101111j146363951995tb00986x, doi101139z04160, doi101159000079744, doi101159000147530, doi101242dev125142701, doi101242jcss310052509, doi1023071535762, doi103166jds1391111, doi105962bhltitle159385, doi105962bhltitle55924, flood1974histochemistry, holmes1953the, openalexw2394638245, openalexw659399033, ruiz1991the, stokes1995ciliary"
}

@article{doi101134s0013873806110145,
    author = "Темерева, Е. Н. and Малахов, В. В.",
    title = "Development of excretory organs in Phoronopsis harmeri (Phoronida): From protonephridium to nephromixium",
    year = "2006",
    journal = "Entomological Review",
    abstract = "Larval protonephridia appear as paired ectodermal invaginations on the posterior body end of the larva (actinotrocha), at early stages of its development. The protonephridium of the early actinotrocha has a straight canal and one group of solenocytes distally. The protonephridium of the late actinotrocha has a U-shaped canal and two (upper and lower) groups of solenocytes. After metamorphosis, solenocytes degenerate and the canal is connected with metacoel. The metanephridial funnel is formed from the upper metacoelomic wall epithelium and the lateral mesentery. The definitive nephridium consists of two parts: the ectodermal canal (derived from the protonephridial canal) and the mesodermal funnel, a derivative of the coelomic epithelium. Thus, the phoronid excretory organ is a nephromixium. Consecutive stages of the evolution of nephridia in phoronids are discussed.",
    url = "https://doi.org/10.1134/s0013873806110145",
    doi = "10.1134/s0013873806110145",
    openalex = "W1988735872",
    references = "doi101242jcss247185103"
}

@book{doi101093acprofoso97801985666870010001,
    author = "Schmidt‐Rhaesa, Andreas",
    title = "The Evolution of Organ Systems",
    year = "2007",
    abstract = "Abstract The field of systematics has developed remarkably over the last few decades. A multitude of new methods and contributions from diverse biological fields — including molecular genetics and developmental biology — have provided a wealth of phylogenetic hypotheses, some confirming traditional views and others contradicting them. There is now sufficient evidence to draw up a ‘tree of life’ based on fairly robust phylogenetic relationships. This book aims to apply these new phylogenies to an evolutionary interpretation of animal organ systems and body architecture. Organs do not appear suddenly during evolution: instead they are composed of far simpler structures. In some cases, it is even possible to trace particular molecules or physiological pathways as far back as pre-animal history. What emerges is a fascinating picture, showing how animals have combined ancestral and new elements in novel ways to form constantly changing responses to environmental requirements. The book starts with a general overview of animal systematics to set the framework for the discussion of organ system evolution. The chapters deal with the general organization, integument, musculature, nervous system, sensory structures, body cavities, excretory, respiratory and circulatory organs, the intestinal and reproductive system, and spermatozoa. Each organ system is presented with its function, the diversity of forms that are realized among metazoan animals, and the reconstruction of its evolution.",
    url = "https://doi.org/10.1093/acprof:oso/9780198566687.001.0001",
    doi = "10.1093/acprof:oso/9780198566687.001.0001",
    openalex = "W589337139",
    references = "burdonjones1952development, dilly1973the, doi101002cne903380405, doi1010079783642651045, doi101007bf00226666, doi101007bf00339290, doi101007bf02584045, doi101016003101829390065q, doi101016009286749290471n, doi101016b9780121064037500173, doi101016b9780122825026500121, doi101016c20090026695, doi101016s002253206180018x, doi101016s0065288108600401, doi101017s0967199400003816, doi101038417271a, doi101038nature01851, doi101073pnas972111359, doi101093icb392189, doi101093icb431166, doi101093oxfordjournalsmolbeva004134, doi101098rspb20001111, doi101098rstb19860056, doi101111j146363951979tb00594x, doi101111j146363951987tb00892x, doi101111j146363951988tb00906x, doi101111j146363951991tb00312x, doi101111j146363951995tb00988x, doi101111j146363951998tb01150x, doi101111j1469185x1974tb01572x, doi101111j1469185x1988tb00631x, doi101111j146979981978tb03931x, doi101126science17239871052, doi101126science28153811342, doi101139z04158, doi101146annureven10010165000525, doi10117711114, doi1012019781315735368, doi101371journalpbio0040291, doi1015159780691206981, doi1023072412825, doi1023073515467, openalexw1484431148, openalexw2772099086, openalexw570196731, openalexw659399033, rähr1979the"
}

@article{doi10118617429994610,
    author = "Ziegler, Alexander and Faber, Cornelius and Bartolomaeus, Thomas",
    title = "Comparative morphology of the axial complex and interdependence of internal organ systems in sea urchins (Echinodermata: Echinoidea)",
    year = "2009",
    journal = "Frontiers in Zoology",
    abstract = {BACKGROUND: The axial complex of echinoderms (Echinodermata) is composed of various primary and secondary body cavities that interact with each other. In sea urchins (Echinoidea), structural differences of the axial complex in "regular" and irregular species have been observed, but the reasons underlying these differences are not fully understood. In addition, a better knowledge of axial complex diversity could not only be useful for phylogenetic inferences, but improve also an understanding of the function of this enigmatic structure. RESULTS: We therefore analyzed numerous species of almost all sea urchin orders by magnetic resonance imaging, dissection, histology, and transmission electron microscopy and compared the results with findings from published studies spanning almost two centuries. These combined analyses demonstrate that the axial complex is present in all sea urchin orders and has remained structurally conserved for a long time, at least in the "regular" species. Within the Irregularia, a considerable morphological variation of the axial complex can be observed with gradual changes in topography, size, and internal architecture. These modifications are related to the growing size of the gastric caecum as well as to the rearrangement of the morphology of the digestive tract as a whole. CONCLUSION: The structurally most divergent axial complex can be observed in the highly derived Atelostomata in which the reorganization of the digestive tract is most pronounced. Our findings demonstrate a structural interdependence of various internal organs, including digestive tract, mesenteries, and the axial complex.},
    url = "https://doi.org/10.1186/1742-9994-6-10",
    doi = "10.1186/1742-9994-6-10",
    openalex = "W2088835246",
    references = "doi101046j14636395200200097x"
}

@article{doi101242dev066852,
    author = "Rink, Jochen C. and Vu, Hanh Thi-Kim and Alvarado, Alejandro Sánchez",
    title = "The maintenance and regeneration of the planarian excretory system are regulated by EGFR signaling",
    year = "2011",
    journal = "Development",
    abstract = "The maintenance of organs and their regeneration in case of injury are crucial to the survival of all animals. High rates of tissue turnover and nearly unlimited regenerative capabilities make planarian flatworms an ideal system with which to investigate these important processes, yet little is known about the cell biology and anatomy of their organs. Here we focus on the planarian excretory system, which consists of internal protonephridial tubules. We find that these assemble into complex branching patterns with a stereotyped succession of cell types along their length. Organ regeneration is likely to originate from a precursor structure arising in the blastema, which undergoes extensive branching morphogenesis. In an RNAi screen of signaling molecules, we identified an EGF receptor (Smed-EGFR-5) as a crucial regulator of branching morphogenesis and maintenance. Overall, our characterization of the planarian protonephridial system establishes a new paradigm for regenerative organogenesis and provides a platform for exploring its functional and evolutionary homologies with vertebrate excretory systems.",
    url = "https://doi.org/10.1242/dev.066852",
    doi = "10.1242/dev.066852",
    openalex = "W2100787580",
    references = "doi101007bf00336662, doi101111j1469185x1974tb01572x"
}

@article{doi101242dev068098,
    author = "Scimone, M. Lucila and Srivastava, Mansi and Bell, George W. and Reddien, Peter W.",
    title = "A regulatory program for excretory system regeneration in planarians",
    year = "2011",
    journal = "Development",
    abstract = "Planarians can regenerate any missing body part, requiring mechanisms for the production of organ systems in the adult, including their prominent tubule-based filtration excretory system called protonephridia. Here, we identify a set of genes, Six1/2-2, POU2/3, hunchback, Eya and Sall, that encode transcription regulatory proteins that are required for planarian protonephridia regeneration. During regeneration, planarian stem cells are induced to form a cell population in regeneration blastemas expressing Six1/2-2, POU2/3, Eya, Sall and Osr that is required for excretory system formation. POU2/3 and Six1/2-2 are essential for these precursor cells to form. Eya, Six1/2-2, Sall, Osr and POU2/3-related genes are required for vertebrate kidney development. We determined that planarian and vertebrate excretory cells express homologous proteins involved in reabsorption and waste modification. Furthermore, we identified novel nephridia genes. Our results identify a transcriptional program and cellular mechanisms for the regeneration of an excretory organ and suggest that metazoan excretory systems are regulated by genetic programs that share a common evolutionary origin.",
    url = "https://doi.org/10.1242/dev.068098",
    doi = "10.1242/dev.068098",
    openalex = "W2120655432",
    references = "doi101007bf00336662, doi101111j1469185x1974tb01572x, doi101111j1469185x1988tb00631x"
}

@article{doi107554elife07405,
    author = "Vu, Hanh Thi-Kim and Rink, Jochen C. and McKinney, Sean and McClain, Melainia and Lakshmanaperumal, Naharajan and Alexander, Richard and Alvarado, Alejandro Sánchez",
    title = "Stem cells and fluid flow drive cyst formation in an invertebrate excretory organ",
    year = "2015",
    journal = "eLife",
    abstract = "Cystic kidney diseases (CKDs) affect millions of people worldwide. The defining pathological features are fluid-filled cysts developing from nephric tubules due to defective flow sensing, cell proliferation and differentiation. The underlying molecular mechanisms, however, remain poorly understood, and the derived excretory systems of established invertebrate models (Caenorhabditis elegans and Drosophila melanogaster) are unsuitable to model CKDs. Systematic structure/function comparisons revealed that the combination of ultrafiltration and flow-associated filtrate modification that is central to CKD etiology is remarkably conserved between the planarian excretory system and the vertebrate nephron. Consistently, both RNA-mediated genetic interference (RNAi) of planarian orthologues of human CKD genes and inhibition of tubule flow led to tubular cystogenesis that share many features with vertebrate CKDs, suggesting deep mechanistic conservation. Our results demonstrate a common evolutionary origin of animal excretory systems and establish planarians as a novel and experimentally accessible invertebrate model for the study of human kidney pathologies.",
    url = "https://doi.org/10.7554/elife.07405",
    doi = "10.7554/elife.07405",
    openalex = "W2115799739",
    references = "doi101007bf00336662"
}

@article{doi101002adfm201603514,
    author = "Gur, Dvir and Palmer, Benjamin A. and Weiner, Steve and Addadi, Lia",
    title = "Light Manipulation by Guanine Crystals in Organisms: Biogenic Scatterers, Mirrors, Multilayer Reflectors and Photonic Crystals",
    year = "2016",
    journal = "Advanced Functional Materials",
    abstract = "Guanine crystals are widely used in nature to manipulate light. The first part of this feature article explores how organisms are able to construct an extraordinary array of optical “devices” including diffuse scatterers, broadband and narrowband reflectors, tunable photonic crystals, and image‐forming mirrors by varying the size, morphology, and arrangement of guanine crystals. The second part presents an overview of some of the properties of crystalline guanine to explain why this material is ideally suited for such optical applications. The high reflectivity of many natural optical systems ultimately derives from the fact that guanine crystals have an extremely high refractive index—a product of its anisotropic crystal structure comprised of densely stacked H‐bonded layers. In order to optimize their reflectivity, many organisms exert exquisite control over the crystal morphology, forming plate‐like single crystals in which the high refractive index face is preferentially expressed. Guanine‐based optics are used in a wide range of biological functions such as in camouflage, display, and vision, and exhibit a degree of versatility, tunability, and complexity that is difficult to incorporate into artificial devices using conventional engineering approaches. These biological systems could inspire the next generation of advanced optical materials.",
    url = "https://doi.org/10.1002/adfm.201603514",
    doi = "10.1002/adfm.201603514",
    openalex = "W2566175409",
    references = "doi101002adfm200901437, doi101007bf00260758, doi101007bf00339290, doi101113jphysiol1965sp007653, doi101242jeb453433"
}

@article{doi101387ijdb170196nh,
    author = "Holland, Nicholas D.",
    title = "The long and winding path to understanding kidney structure in amphioxus - a review",
    year = "2017",
    journal = "The International Journal of Developmental Biology",
    abstract = "The history of studies on amphioxus kidney morphology is reviewed with special attention to four zoologists who made important early contributions. In 1884, Hatschek described a single anterior nephridial tubule in larval and adult amphioxus. Subsequently, in 1890, Weiss and Boveri independently found multiple branchial nephridia (morphologically similar to Hatschek's nephridium) associated with the pharyngeal gill slits. These initial discoveries set the stage for Goodrich to criticize Boveri repeatedly for the latter's contention that amphioxus nephridia develop from mesoderm and are connected to neighboring coeloms throughout the life history. In the end, Boveri was almost certainly correct about amphioxus nephridia developing from mesoderm and at least partly right about the lumen of the nephridial tubules being connected to nearby coeloms-the openings are present during larval stages but are closed off later in development. The more detailed structure of amphioxus nephridial tubules was ultimately revealed by electron microscopy. The tubule epithelium includes specialized excretory cells (cyrtopodocytes), each characterized by a basal region similar to that of a vertebrate renal podocyte and an apical region bearing a flagellar/microvillar process reminiscent of an invertebrate protonephridium. At present, in spite of considerable progress toward understanding the development and structure of amphioxus nephridia, virtually nothing is yet known about how they function, and no consensus has been reached about their phylogenetic significance.",
    url = "https://doi.org/10.1387/ijdb.170196nh",
    doi = "10.1387/ijdb.170196nh",
    openalex = "W2782732910",
    references = "doi101016s002253206180018x, doi101017s002531540004813x, doi101038048613a0, doi101038078267a0, doi101111j146363951998tb01150x, doi101186s4085101600383, doi101242jcss231123445, doi101242jcss262246243, doi101242jcss262248539, doi101242jeb203223381, doi101387ijdb072436jg, doi1015259780520328426, doi1023073225209, doi1024448ethz1890, holmes1953the, moller1974fine, nakao1965the"
}

@article{doi103389fnins2022812223,
    author = "Gattoni, Giacomo and Andrews, Toby G. R. and Benito‐Gutiérrez, Èlia",
    title = "Restricted Proliferation During Neurogenesis Contributes to Regionalisation of the Amphioxus Nervous System",
    year = "2022",
    journal = "Frontiers in Neuroscience",
    abstract = "at specific time points in development, and inhibiting cell division during neurulation, we demonstrate that localised proliferation in the anterior cerebral vesicle is required to establish the full cell type repertoire of the frontal eye complex and the putative hypothalamic region of the amphioxus brain, while posterior proliferating progenitors, which were found here to derive from the dorsal lip of the blastopore, contribute to elongation of the caudal floor plate. Between these proliferative domains, we find that trunk nervous system differentiation is independent from cell division, in which proliferation decreases during neurulation and resumes at the early larval stage. Taken together, our results highlight the importance of proliferation as a tightly controlled mechanism for shaping and regionalising the amphioxus neural axis during development, by addition of new cells fated to particular types, or by influencing tissue geometry.",
    url = "https://doi.org/10.3389/fnins.2022.812223",
    doi = "10.3389/fnins.2022.812223",
    openalex = "W4220944387",
    references = "doi101016bsctdb202007001"
}