臺灣博碩士論文加值系統

摘要

本論文旨在探討台灣地區南亞蝸牛科栗蝸牛屬之一樹棲群，白高腰蝸牛與其近緣種之系統分類與親緣關係。所有本島栗蝸牛屬物種之親緣關係亦予檢視，以分子證據重建其演化史與探究其種化機制。

第一章對南亞蝸牛科之系統分類特徵及與台灣本科動物相相關之分類爭議與研究史予以簡介。

第二章針對樹棲種群白高腰蝸牛與其近似種進行詳盡模式標本檢視，並由模式產地採集證據標本供分子分析，本研究選取之分子標記為粒線體 DNA CO 1 基因片段序列。對於本島各地採取之所有近似種類進行生殖系統之比較解剖與分子親緣分析後，原本認定為白高腰蝸牛亞種的奇異高腰蝸牛與艷美高腰蝸牛應提升為獨立種，而在全島各地採集之近似於白高腰蝸牛的類群共鑑識出 14 個新種，這些新種具有地理分布與棲地上的侷限性，皆為樹棲、夜行與植食性種類，遺傳結構與生殖系統型態上具有明顯特徵足堪辨識。

第三章以一種廣布的地棲性栗蝸牛為研究對象，探討其族群遺傳結構並藉此偵測隱蔽種。栗蝸牛是廣泛分布於臺灣西部地區的地棲性特有種南亞蝸牛。利用粒線體 DNA CO 1 基因序列片段，分析來自 11 個樣點 68 隻栗蝸牛個體，探討其族群遺傳結構。結果顯示栗蝸牛分為北、中、南三大群，各群有其遺傳特色且群間無明顯基因交流。遺傳多樣性以南部群最高，新竹地區的北部群最低且與其他二群遺傳距離最遠。此外，於高雄、屏東、花蓮及台東等地採集之栗蝸牛亞種與外形相似之種類，遺傳與親緣分析皆顯著異於栗蝸牛，屬於不同物種。

第四章探討台灣產南亞蝸牛科的詳盡親緣關係與演化史，所有本島產本科物種皆予以討論。本研究利用粒線體 DNA CO 1 與 16S rRNA 以及核基因 ITS 等基因序列片段為分子標記，結果顯示本科栗蝸牛屬內物種種化的機制複雜，包含空間分化之後生態棲位改變導致之種化事件；單基因突變造成殼體對稱旋性反轉而引起之種化；以及地理空間上長期發生之擴散分化或分裂分化導致之種化事件，顯示在一封閉島嶼的屬內種化事件仍可能由多起源因素所致。

ABSTRACT

This dissertation concerns the systematics and phylogeny of a genus Satsuma (Pulmonata: Camaenidae) land snail group, Satsuma albida and its akin species from Taiwan. The phylogenetic relationships of the whole Satsuma species on this island are discussed in order to confer the evolutionary history and mechanism of their species formation.

In the Chapter One, a general introduction is given on the systematics of the Camaenidae family. Taxonomy of species, studies of history and classification controversy in this group from Taiwanese camaenids fauna are also discussed.

In the Chapter Two, the author apply traditional taxonomy method as comparative anatomy of the genital system, with the molecular survey was used to probe into the phylogenetic relationships of an arboreal Satsuma species complex from Taiwan, called Satsuma albida species complex. In this study, fifteen species were identified and described as new species from the group. Two subspecies of S. albida, S. a. insignis and S. a. mollicula were promoted to an independent species based on the characters of their reproductive system and the molecular phylogenetic relationships from other taxa. The reasons of species formation are also discussed, which provide more evolutionary evidences of the Satsuma snails from Taiwan.

In the Chapter Three, the author used partial sequences of mtDNA CO 1 gene was used as the molecular marker to survey the population genetic structure of the terrestrial endemic Satsuma species, S. nux and its subspecies, which is widely distributed around Taiwan. After employing the molecular analysis, the true S. nux, which were conformed to the type specimen, were proved that only distributed in lowland areas of western Taiwan. Other S. nux like species should be recognized as independent species. It means that they are cryptic species of S. nux. Other two subspecies of S. nux, S. n. paiwanis and S. n. litus should seem as independent species as well. But the subspecies S. n. sericata is a synonym of S. nux according to the close genetic distance and similarity in the genetic structure to the S. nux population. The population genetic structure of S. nux can be divided into three deep clades, each group provides with unique haplotypes that are not shared between groups. These three groups may have diverged a long time ago via retreat and expansion events from different genetic sources several times.

In the Chapter Four, an explicit phylogenetic relationship of all Taiwanese Camaenidae land snails are shown, which is based on the molecular markers of mtDNA and nucleus genes reflecting their evolutionary history. Species formation can be promoted via ecological reasons, such as spatial allocation in the group of arboreal species; or via single-gene mutation such as chiral reverse from sinistral to dextral shells. Such can cause mismatch mating and procure incipient species formation. Speciation can also be happened with a long term evolutionary process, through the vicariance or dispersal events and cause a monophyletic clade within high diversity taxa on the species level. Thus, these snails revealed a multiple origin of incipient speciation motive force within a genus even though confined through an island.

Contents
口試委員會審定書..............................................................................................i
謝詞.....................................................................................................................ii
中文摘要............................................................................................................iii
Abstract...............................................................................................................iv
Chapter One General Introduction..............................................................1
References....................................................................................................3
Chapter Two Systematic Revision of the Arboreal Snail Satsuma albida Species Complex (Pulmonata: Camaenidae) with Descriptions of Fourteen New Species from Taiwan........................................................6
Introduction..................................................................................................6
Materials and Methods................................................................................8
Results........................................................................................................10
Discussion..................................................................................................56
References..................................................................................................61
Figures.......................................................................................................65
Tables.......................................................................................................103
Chapter Three Population Genetics of the Endemic Land Snail Satsuma nux (Pulmonata: Camaenidae) from Taiwan with Preliminary Phylogenetic Study of Its Akin Species................................................107
Introduction..............................................................................................107
Materials and Methods............................................................................107
Results......................................................................................................109
Discussion................................................................................................111
References................................................................................................114
Figures.....................................................................................................119
Tables.......................................................................................................123
Chapter Four Incipient Species Formation via Multiple Origins through an Island.........................................................................................................127
Introduction..............................................................................................127
Materials and Methods............................................................................129
Results......................................................................................................129
Discussion................................................................................................131
References................................................................................................133
Figures.....................................................................................................135
Figure legends.........................................................................................137
Tables.......................................................................................................139

Chapter1
Abbott RT. 1989. Compendium of Landshells. VII+240. American Malacologists, Inc., Burlington, MA, USA.
Brown B, Emberson RM, Paterson AM. 1999. Mitochondrial COI and II provide useful markers for Weiseana (Lepidoptera, Hepialidae) species identification. Bull. Entomol. Res. 89: 287-294.
Bucklin A, Guarnieri M, Hill RS, Bentley AM, Kaartvedt S. 1999. Taxonomic and systematic assessment of planktonic copepods using mitochondrial COI sequence variation and competitive, species-specicific PCR. Hydrobiology 401:239-254.
Chang KM, Chang HW, Hwang CC. 1996. Anatomy on Satsuma albida (H. Adams, 1870) from Taiwan (Pulmonata: Camaenidae). Bulletin of Malacology, ROC. 20: 25-30.
Habe T. 1955. Anatomical studies of Japanese land snails (3). Venus 18 (4): 221-234.
Hebert PDN, Cywinska A, Ball SL, deWaard JR. 2003a. Biological identifications through DNA barcodes. Proc. R. Soc. Lond. B 270: 313-321.
Hebert, P. D. N., S. Ratnasingham, and J. R. DeWaard. 2003b. Barcoding animal life: cytochome c oxidase subunit 1 divergences among closely related species. Proc. R. Soc. Lond. B 270: 96-99.
Hsieh BC, Hwang CC, Wu SP. 2006. Landsnails of Taiwan (2nd ed.). Forestry Bureau Council of Agriculture, Executive Yuan, Taipei, Taiwan. 277 pp.
Jordan DS. 1908. The low of geminate species. The American Naturalist XVII (494): 73-80.
Kuroda T. 1941. A catalogue of molluscan shells from Taiwan (Formosa), with description of new species. Memoirs of the Faculty of Science and Agriculture, Taihoku Imperial University 22: 65-216.
Kuroda T. 1958. Land shell fauna of Japan and her adjacent regions (4). Venus 20 (1): 132-158.
Minato H. 1976. Genital studies of the Japanese land snails. VII. The genitalia of Satsuma amanoi Kuroda, 1960 and S. tanegashimae (Pilsbry, 1901). Venus 35 (2): 83-86.
Minato H. 1980. Land shells fauna of Miyako Islands, the southern Ryukyu, Japan. Venus 39 (2): 83-99.
Ohara K., Otani Y. 2002. Catalogue of the Dr. Tokubei Kuroda shell collection deposited in the Nishinomiya Shel Museum. Part 1 Non-marine Gastropoda. Bulletin of the Nishinomiya Shell Museum 1: 1–139.
Pilsbry HA, Hirase Y. 1906. Catalogue of the land and freshwater molluscs of Taiwan (Formosa) with description of new species. Proceedings Academic Natural Science Philadelphia 57: 720-752.
Richardson L. 1985. Camaenidae: catalog of species. Tryonia 12: 1-479.
Sinagawa K. 1980. Preliminary report of reproductive system of two Camaenidae species from Taiwan. Kainakama 13 (4): 6-8.
Solem A. 1997. Camaenid land snails from Western and central Australia (Mollusca: Pulmonata: Camaenidae) VII Taxa from Dampierland through the Nullbor. Western Australian Museum, Perth, AU. p. 1461-1906.
Wu SP, Wu WL. 1998. The Distribution of Camaenidae in Taiwan. Bulletin of Malacology, ROC. 22: 43-48.
Zilch A. 1959-1960. Gastropda, Teil 2, Euthyneura. Handbuch der Paläozoologie 6 (2): 834.
Chapter 2
Adams H. 1870. Description of ten new species of land and freshwater shells collected by Robert Swinhoe, Esq., in China and Taiwan. Proceedings Zoological Society of London, 1870: 377-379.
Avies JC. 2000. Phylogeography. Harvard University Press, London, UK. 447 pp.
Baker HB. 1963. Type land snails in the Academy of Natural Sciences of Philadelphia. Part II. Land Pulmonata, exclusive of North America and Mexico. Proceedings of the Academy of Natural Sciences of Philadelphia 115: 191-259.
Chai BHT. 1972. Structure and tectonic evolution of Taiwan. American Journal of Science 272: 389-422.
Chang KM. 1992. Dwarf type of Camaena batanica pancala (Schmacker and Boettger) from South Cape, Taiwan and its allied species (Pulmonata: Camenidae). Bulletin of Malacology, ROC. 17: 11-20.
Chang KM, Chang HW, Hwang CC. 1996. Anatomy on Satsuma albida (H. Adams, 1870) from Taiwan (Pulmonata: Camaenidae). Bulletin of Malacology, ROC. 20: 25-30.
Felsenstein J. 1985.Confidence limits on phylogenies: an approach using the bootstrap. Evolution 39: 783-791.
Folmer O, Hoeh MBW, Lutz R, and Vrijenhoer R. 1994. DNA primers for amplication of mitochondrial cytochrom c oxidase subunit 1 from diverse metazoan invertebrates. Molecular Marine Biology and Biotechnology 3: 294-299.
Gómez BJ. 2001. Structure and Functioning of the Reproductive System pp. 307-330. in GM Baker (ed.) The Biology of Terrestrial Molluscs. CABI Publishing, Oxon, UK. 558 pp.
Habe T. 1955. Anatomical studies of Japanese land snails (3). Venus 18 (4): 221-234.
Hall TA. 1999. BioEdit: a user-friendly biological sequence alignment editor and analysis program for Windows 95/98/NT. Nucleic Acids Symp Ser 41: 95-98.
Hsieh BC, Hwang CC, Wu SP. 2006. Landsnails of Taiwan (2nd ed.). Forestry Bureau Council of Agriculture, Executive Yuan, Taipei, Taiwan. 277 pp.
Huelsenbeck JP, Ronquist F. 2001. MRBAYES: Bayesian inference of phylogeny. Bioinformatics 17: 754-755.
Kerney MP, Rad C. 1979. Land snails of Britain & north-west Europe. London: HarperCollins.
Kuroda T. 1941. A catalogue of molluscan shells from Taiwan (Formosa), with description of new species. Memoirs of the Faculty of Science and Agriculture, Taihoku Imperial University 22: 65-216. (in Japanese)
Kuroda T, Habe T. 1949. Helicacea. 129 pp. (p. 53, 59), Sanmeisha, Tokyo.
Kuroda T. 1958. Land shell fauna of Japan and her adjacent regions (4). Venus 20 (1): 132-158.
Lin CC. 1970. The Quaternary Period of Taiwan. Bibliography of Taiwan, Taipei, Taiwan.
Minato H. 1976. Genital studies of the Japanese land snails. VII. The genitalia of Satsuma amanoi Kuroda, 1960 and S. tanegashimae (Pilsbry, 1901). Venus 35 (2): 83-86.
Minato H. 1980. Land shells fauna of Miyako Islands, the southern Ryukyu, Japan. Venus 39 (2): 83-99.
Nylander JAA. 2004. MrModeltest v2. Program distributed by the author. Evolutionary Biology Centre, Uppsala University.
Palumbi SR. 1996. What can molecular genetics contribute to marine biogeography. An urchin’s tale. Journal of Experimental Marine Biology and Ecology 203: 75-92.
Pilsbry HA, Hirase Y. 1906. Catalogue of the land and freshwater molluscs of Taiwan (Formosa) with description of new species. Proceedings Academic Natural Science Philadelphia 57: 720-752.
Pilsbry HA, Hirase Y. 1909. New land molluscs of the Japan Empire. Proceedings Academic Natural Science Philadelphia 60: 593-594.
Ronquist F, Huelsenbeck JP. 2003. MRBAYES 3: Bayesian phylogeneticinference under mixed models. Bioinformatics 19: 1572-1574.
Saitou N, and Nei M. 1987. The neighbor joining method: a new method for reconstructing phylogenetic trees. Mol. Biol. Evol. 4: 406-425.
Sinagawa K. 1980. Preliminary report of reproductive system of two Camaenidae species from Taiwan. Kainakama 13 (4): 6-8.
Swofford DL. 2000. PAUP. Phylogenetic Analysis Using Parsimony. Version 4. Sinauer Associates, Sunderland, MA, USA.
Teng LS. 1990. Geotectonic evolution of late Cenozoic arc-continent collision in Taiwan. Tectonophysics 183: 57-76.
Thompson JD, Higgins DG and Gibson PJ. 1994. CLUSTAL W: improving the sensitivity of progressive multiple sequence alignment through sequencing weighting, position-specific gap penalties and weight matrix choice. Nucleic Acid Res. 22: 4673-4680.
Truett GE, Heeger P, Mynatt RL, Truett AA, Walker JA, Warman JL. 2000. Preparation of PCRQuality Mouse Genomic DNA with Hot Sodium Hydroxide and Tris (HotSHOT). BioTechniques 29: 52-54.
Verdcourt B. 2000. The penial armature of three species of east African Streptaxidae (Gastropoda, Stylommatophora). Folia Malacologica 8 (3): 215-221.
Wu SP, Wu WL. 1998. The Distribution of Camaenidae in Taiwan. Bulletin of Malacology, ROC. 22: 43-48.
Chapter3
Avies JC. 2000. Phylogeography. Harvard University Press, London, UK. 447 pp.
Chai BHT. 1972. Structure and tectonic evolution of Taiwan. American Journal of Science 272: 389-422.
Chang HW. 1993. Ecological methods for study non-marine mollusks. Chinese Bioscience 36: 65-70.
Chang KM, Tada A. 2000. Coniglobus nux litus n. subsp. from Taiwan (Pulmonata : Camaenidae). Bulletin of Malacology, ROC 24: 7-12.
Chiba S. 1999. Accelerated evolution of land snails Mandarina in the oceanic Bonin islands: evidence from mitochondrial DNA sequences. Evolution 53 (2): 460-471.
Doyle JJ, Doyle JL. 1987. A rapid DNA isolation procedure for small amounts of fresh leaf tissue. Phytochem. Bull. 19: 11-15.
Excoffier L, Smouse PE. 1994. Using allele frequencies and geographic subdivision to reconstruct gene trees within a species: molecular variance parsimony. Genetics 136: 343-359.
Felsenstein J. 1985.Confidence limits on phylogenies: an approach using the bootstrap. Evolution 39: 783-791.
Folmer O, Hoeh MBW, Lutz R, Vrijenhoer R. 1994. DNA primers for amplication of mitochondrial cytochrom c oxidase subunit 1 from diverse metazoan invertebrates. Molecular Marine Biology and Biotechnology 3: 294-299.
Hall TA. 1999. BioEdit: a user-friendly biological sequence alignment editor and analysis program for Windows 95/98/NT. Nucleic Acids Symp Ser 41: 95-98.
Hawkins JW, Lankester MW, Nelson RRA. 1998. Sampling terrestrial gastropods using cardboard sheets. Malacologia 39(1-2): 1-9.
Hebert PDN, Cywinska A, Ball SL, DeWaard JR. 2003a. Biological identifications through DNA barcodes. Proc. R. Soc. Lond. B 270: 313-321.
Hebert PDN, Ratnasingham S, DeWaard JR. 2003b. Barcoding animal life: cytochome c oxidase subunit 1 divergences among closely related species. Proc. R. Soc. Lond. B 270: 96-99.
Hsieh BC, Hwang CC, Wu SP. 2006. Landsnails of Taiwan (2nd ed.). Forestry Bureau Council of Agriculture, Executive Yuan, Taipei, Taiwan. 277 pp.
Hsu FH. 2000. Phylogeographic structure in mtDNA of the Formosan White-bellied Rat Niviventer culturatus and Formosan Wood Mouse Apodemus semotus. Ph. D’s thesis, National Taiwan Univ., Taipei, Taiwan.
Hsu FH, Lin FJ, Lin YS. 2000. Phylogeographic Variation in Mitochondrial DNA of Formosan white-bellied Rat Niviventer culturatus. Zoological Studies 39(1): 33-46.
Huang S, Chiang YC, Schaal BA, Chou CH, Chiang TY. 2001. Organelle DNAs phylogeography of Cycas taitungensis, a relict specices in Taiwan. Molecular Ecology 10: 2669-2681.
Huelsenbeck JP, Ronquist F. 2001. MRBAYES: Bayesian inference of phylogeny. Bioinformatics 17: 754-755.
Kimura M. 1980. A simple method for estimating evolutionary rates of base substitutions through comparative studies of nucleotide sequences. J. Mol. Evol. 16: 111-120.
Kumar S, Tamura K, Nei M. 2004. MEGA 3: integrated software for molecular evolutionary genetics analysis and sequence alignment. Briefings in Bioinformatics 5: 150-163.
Kuroda T. 1941. A catalogue of molluscan shells from Taiwan (Formosa), with description of new species. Memoirs of the Faculty of Science and Agriculture, Taihoku Imperial University 22: 65-216.
Lin CC. 1970. The Quaternary Period of Taiwan. Bibliography of Taiwan, Taipei, Taiwan.
Lin SM, Chen CA, Lue KY. 2002. Molecular phylogeny and biogeography of the grass lizards genus Takydromus (Reptilia: Lacertidae) of east Asia. Mol. Phyl. Evol. 22: 276-288.
Lu SY, Hong KH, Liu SL, Cheng YP, Wu WL, Chiang TY. 2002. Genetic variation and population differentiation of Michelia formosana (Magnoliaceae) based on cpDNA variation and RAPD fingerprints: relevance to post-Pleistocene recolonization. Journal of Plant Research 115: 203-216.
Meegaskumbura M, Bossuyt F, Pethiyagoda R, Manamendra-Arachchi K, Milinkovitch MC, Schneider CJ. 2002. Sri Lanka: An Amphibian Hot Spot. Science 298: 379.
Moritz C, Dowling TE, Brown WM. 1987. Evolution of animal mitochondrial DNA: relevance for population biology and systematics. Ann. Rev. Ecol. Syst. 18: 269-292.
Nylander JAA. 2004. MrModeltest v2. Program distributed by the author. Evolutionary Biology Centre, Uppsala University.
Ota H. 1991. Systematics and biogeography of terrestrial reptiles of Taiwan. In “Proceedings of the first international Symposium on Wildlife Conservation, ROC.” ed. by Lin YS and Chang KH, Council of Agriculture, Taipei, p. 47-112.
Ronquist F, Huelsenbeck JP. 2003. MRBAYES 3: Bayesian phylogeneticinference under mixed models. Bioinformatics 19: 1572-1574.
Rozas J, Sanchez-DelBarrio JC, Messeguer X, Rozas R. 2003. DnaSP, DNA polymorphism analysis by the coalescent and other methods. Bioinformatics 19: 2496-7.
Saitou N, Nei M. 1987. The neighbor joining method: a new method for reconstructing phylogenetic trees. Mol. Biol. Evol. 4: 406-425.
Shih HT, Hung HC, Schubart CD, Chen CA, Chang HW. 2006. Intraspecific genetic diversity of the endemic freshwater crab Candidiopotamon rathbunae (Decapoda, Brachyura, Potamidae) reflects five million years of the geological history of Taiwan. Journal of Biogeography 33: 980-989.
Swofford DL. 2000. PAUP. Phylogenetic Analysis Using Parsimony. Version 4. Sinauer Associates, Sunderland, MA, USA.
Teng LS. 1990. Geotectonic evolution of late Cenozoic arc-continent collision in Taiwan. Tectonophysics 183: 57-76.
Thomaz D, Guiller A, Clarke B. 1996. Extreme divergence of mitochondrial DNA within species of pulmonate land snails. Proc. R. Soc. Lond. B 263: 363-368.
Thompson JD, Higgins DG, Gibson PJ. 1994. CLUSTAL W: improving the sensitivity of progressive multiple sequence alignment through sequencing weighting, position-specific gap penalties and weight matrix choice. Nucleic Acid Res. 22: 4673-4680.
von Möllendorff OF. 1888. Diagnoses specierum novarum sinensium. Nachrichtsblatt der Deutschen Malakozoologischen Gesellschaft 20(3/4): 38-44.
Wang HY, Tsai MP, Yu MJ, Lee SC. 1999. Influence of glaciation on divergence patterns of the endemic minnow, Zacco pachycephalus, in Taiwan. Molecular Ecology 8: 1879-1888.
Wang JP, Lin HD, Huang S, Pan CH, Chen XL, Chiang TY. 2004. Phylogeography of Varicorhinus barbatulus (Cyprinidae) in Taiwan based on nucleotide variation of mtDNA and allozymes. Molecular Phylogenetics and Evolution 31: 1143-1156.
Wu SP, Wu WL. 1998. The Distribution of Camaenidae in Taiwan. Bulletin of Malacology, ROC 22: 43-48.
Wu WK, Chang KM. 1975. Anatomy of the land snail Ganesella (Coniglobus) nux (Möllendorff). Bulletin of Malacology, ROC 2: 107-111.
Yeh WS. 1997. Phylogeographic structure of Rhacophorus moltrechti. Master’s thesis, National Taiwan Univ., Taipei, Taiwan.
Chapter4
Asami T, Cowie RH, Ohbayashi K. 1998. Evolution of Mirror Images of Sexually Asymmetric Mating Behavior in Hermaphroditic Snails. The American Naturalist 152: 225-236.
Brock JP. 2000. The Evolution of Adaptive Systems. Academic Press, San Diego, CA, USA.
Chang KM. 1992. Dwarf type of Camaena batanica pancala (Schmacker and Boettger) from South Cape, Taiwan and its allied species (Pulmonata: Camenidae). Bulletin of Malacology, ROC 17: 11–20.
Cracraft J. 1989. Speciation and its ontology: The empirical consequences of alternative species concepts for understanding patterns and processes of differentiation. pp. 28-59. in Otte D and Endler JA (eds.) Speciation and Its Consequences. Sinauer Associates, Sunderland, MA, USA.
de Queiroz K, Donoghue MJ. 1988. Phylogenetic systematics and the species problem. Cladistics 4: 317-338.
Goodacre SL, Wade CM. 2000. Molecular evolutionary relationships between partulid land snails of the Pacific. Proc. R. Soc. Lond. B 268: 1-7.
Kuroda T, Habe S. 1949. Helicacea. Sanmeisha, Tokyo, 129 pp.
Mayr E. 1995. Species, classification, and evolution. pp. 3-12. in Arai R, Kato M, Doi Y (eds.) Biodiversity and Evolution. National Science Museum Foundation, Tokyo, Japan.
Orr HA. 1991. Is Single-Gene Speciation Possible? Evolution 45 (3): 764-769.
Schluter D. 2000. The Ecology of Adaptive Radiation. Oxford Univ. Press Inc., NY, USA.
Gittenberger E. 1988. Sympatric Speciation in Snails: a Largely Neglected Model. Evolution 42 (4): 826-828.
Ueshima R, Asami T. 2003. Single-gene speciation by left-right reversal. Nature 425: 679.
Weston PH. 1999. Process morphology from a cladistic perspective. pp. 124-144. in Scotland R, Pennington RT (eds.) Homology and Systematics. The Systematics Association Special Volume Series 58.