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Thesis (PhD)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Freshwater organisms, such as crabs (Crustacea: Decapoda: Brachyura), are useful in studies examining inland historical biogeographic patterns and speciation because they are isolated to specific drainage systems, which often serve as barriers to gene flow. The Afrotropical freshwater crab fauna (Potamonautidae) present ideal organisms for investigating hypothesis relating to evolutionary histories because they occur on continental Africa (sub-Sahara) and islands. However, there is a great deal of undiscovered freshwater crab diversity, especially with the prevalence of undiscovered cryptic lineages, which are poorly studied among freshwater crabs, leading to uncertain regional diversity. In this research, multiple genetic (mt- and nuDNA) markers were used to infer the phylogenetic relationships and the biogeographical histories of the Afrotropical freshwater crab superfamily, Potamonautidae. Divergence time estimations were used to infer biogeographic histories, to ascertain whether speciation could be linked to past geologic and / or climatic events. Two widely distributed Potamonautes species complexes were targeted for the investigation of regional cryptic species diversity. In Chapter 2, the intraspecific phylogenetic variability within Potamonautes perlatus sensu lato occurring on the Cape Fold Mountain range (South Africa) was examined, with sampling localities occurring in western- and southern flowing drainages. Previous research suggested possible cryptic speciation within this species complex; however, no tangible inferences could be made because of analytical constraints. Two major clades were recovered: one corresponding to western flowing drainages and another to southern flowing drainages. Moreover, three cryptic lineages were recovered: P. perlatus sensu stricto, restricted to western flowing drainages, and two geographically discrete novel cryptic lineages from the southern flowing drainages, described as P. barbarai sp. nov and P. barnardi sp. nov., with divergence (±2.61 Mya) linked to Pleistocene climatic events. Subsequent to the recovery of the two novel lineages from the Cape Fold Mountain range, the Pleistocene climatic events. Subsequent to the recovery of the two novel lineages from the Cape Fold Mountain range, the revision of the P. clarus / P. depressus species complex from the Tugela and uMkomazi drainages (Drakensberg Mountain range, South Africa) was conducted. This species complex was previously found to comprise at least five cryptic lineages (Chapter 3). A coalescent multilocus (three mt- and three nuDNA) Bayesian species delimitation method was used, and an additional three cryptic lineages were recovered, bringing the total to eight species (two already described as P. clarus and P. depressus), with divergence having occurred approximately 10.3 Mya. Following the recent discovery of novel freshwater crab lineages in the mountainous areas of Mozambique and Malawi, a sampling trip to the Zimbabwean Highlands was undertaken, where a novel freshwater crab species was discovered and described as P. mutareensis, highlighting the need to sample high-lying regions (Chapter 4). Furthermore, two additional novel lineages from Mozambique (P. bellarussus sp. nov.) and the Mpumalanga Province in South Africa (P. flavusjo sp. nov) were described (Chapter 5). In Chapter 6, increased taxon sampling, with additional specimens acquired from various museums and personal collections was used to obtain a better resolution of the phylogeny of the Afrotropical Potamonautidae and to infer the ancestral affinities of the two sub-families, Deckeniinae and Potamonautinae. The Potamonautidae were found to have speciated eastward from West Africa, with a late Cretaceous divergence (±107 – 96.04 Mya). The Potamonautinae originated in West Africa (three genera), while the paraphyletic Potamonautes and Platythelphusa had East African affinities. Potamonautes was not monophyletic, comprising several fragmented geographic clades, which may suggest that this genus requires revision. Nevertheless, the overall speciation within the Potamonautidae reflects past geological and climatic events, such as rifting and uplift episodes and the contraction of forests, which occurred from the Tertiary onwards.

Thesis (M. Phil.)--University of Hong Kong, 1991.

Crabs are conspicuous inhabitants of temperate salt marshes and tropical mangroves and interact with their environment through several processes. However, detailed information on crab community processes is absent for most South African estuaries and nearshore coastal regions. This study evaluated the primary producers supporting crab species in the salt marsh dominated Swartkops estuary and the mangrove Mngazana estuary. Various methods estimating crab abundances were also assessed in different microhabitats and the larval distribution of crabs in the coastal zone was also investigated. Various methods for estimating crab abundance have been employed in the past, each with its inherent biases. The microhabitat of a mangrove forest in Australia was structurally altered by the manipulation of the litter, pneumatophores and the associated algae. These alterations did not affect the behavioural activity or the numbers of crabs recorded in any of the experimental treatments by either visual counts or pitfall traps. However, the number of crabs caught in the pitfall traps differed between the sites. Species-specific behaviour which was not investigated in this study may bias crab abundance estimates when using pitfall traps and therefore requires further investigation. Benthic consumers inhabiting shallow coastal environments may ultimately have the origin of their nutrition in a number of possible sources. Isotopic and gut content analysis of Thalamita crenata and juvenile Scylla serrata in the Mngazana estuary in South Africa revealed that these two portunids are able to share a habitat by resource partitioning. Differences were noted for species-specific utilization of primary producers not only between seasons within a site, but also between sites. This highlighted the use of locally produced primary producers sustaining food webs in estuaries. Mangrove production in the Mngazana estuary is very important and contributes to most of the carbon in the underlying sediments in the mangrove forest. However, the relatively large number of species and biomass encountered in this estuary may also be attributed to the fact that the different species are able to exploit of a number of different resources. The variation in stable isotope analysis of the different crab species throughout the estuary indicated that these crabs able to occupy the same habitat by feeding on a number of different resources and may preferentially select for a specific primary producer. A stable isotope of crabs in the salt marsh Swartkops estuary indicated that the dominant primary producer sustaining crab communities may even take place on a relatively smallscale. Sesarma catenata found at the inner marsh site recorded more depleted carbon signatures than those encountered in the other sites approximately 100 m away, and reflected signatures similar to the locally-encountered inner marsh plants. The relatively enriched nitrogen signatures of the anthropogenically-impacted Swartkops estuary is an indication of extensive inputs due to urbanization and industrialization, in contrast to the relatively pristine Mngazana estuary which exhibited low nitrogen signatures. Emphasis has been placed on the abiotic component of the exchange of nutrients and energy, although living organisms may also be transported, both actively and passively, between ecosystems. Little variation in either species composition or abundance was found between seasons for the larval distribution of brachyuran crabs on the east coast of South Africa. Due to the lack of published larval descriptions, larvae could not be identified to species level and it was therefore not possible to identify whether the larvae were hatched or spawned in an estuary or in a marine environment, or whether the larvae originated in the northern tropical regions. Frequent wind-reversals which are common in this region may retain larvae close inshore and supply the southern temperate locations with larvae from the northern locations. In conclusion, this study has shown that in highly productive systems with a number of potential primary producers, the crabs that inhabit the estuary show a marked diversity in resource utilization which could potentially allow a number of closely related species to occupy different trophic levels. This study also highlights the importance of locally produced sources in an estuary, which may occur on very small scales and this needs to be factored in with the design of any future stable isotope studies of this nature.

Orientador: William Ricardo Amancio Santana / Resumo: O gênero anfi-americano Macrocoeloma Miers, 1879 é composto por caranguejos decoradores de habitats tropicais e subtropicais. Esses caranguejos são encontrados em substratos distintos, incluindo principalmente recifes de corais e rochas. Esse gênero passou por várias alterações sistemáticas em seu status de família, desde sua descrição original até a sua recente exclusão de Mithracidae. No início deste estudo Macrocoeloma era considerado incertae sedis, devido ao pouco conhecimento das relações entre as espécies do gênero e outros gêneros relacionados, sendo sua revisão taxonômica sugerida diversas vezes na literatura. Assim, com o objetivo de suprir essas lacunas taxonômicas e filogenéticas, este estudo empregou abordagens morfológicas e moleculares para reconstruir as relações filogenéticas de Macrocoeloma. Para isso, utilizamos um conjunto de dados moleculares combinados de um gene nuclear (18S) e três mitocondriais (12S, 16S, COI), usando máxima verossimilhança e inferência bayesiana. Além disso, uma inferência de delimitação de espécies foi realizada com o modelo de Poisson tree processes (PTP), usando a filogenia de máxima verossimilhança do gene mitocondrial COI. Foi realizada a revisão taxonômica de Macrocoeloma, com diagnóstico elaborado, descrições detalhadas e mapas de distribuição geográfica com base no material examinado. A monofilia de Macrocoeloma foi demonstrada, após exclusão de Pericera heptacantha Bell, 1836 e P. septemspinosa Stimpson, 1871. O gênero monot... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The amphi-American genus, Macrocoeloma Miers, 1879, is composed of decorator crabs from tropical and subtropical regions. These crabs are found on distinct substrates, including mainly coral reefs and rock. Macrocoeloma has undergone several systematic changes in its family status, since the original description until its recent exclusion of Mithracidae. Prior to this study, Macrocoeloma was considered incertae sedis, due to little knowledge of the relationships between species of the genus and related genera, and its taxonomic revision has been suggested several times in the literature. Thus, in order to address these taxonomic and phylogenetics gaps, this study employed morphological and molecular approaches to reconstruct the phylogenetic relationships of Macrocoeloma. We used a combined molecular dataset of a nuclear (18S) and three mitochondrial genes (12S, 16S, COI) using Maximum Likelihood and Bayesian Inference. In addition, the inference of species delimitation was performed with the Poisson tree processes model (PTP), using Maximum Likelihood phylogeny of the mitochondrial COI gene. The taxonomic revision of Macrocoeloma was provided with elaborated diagnosis, detailed descriptions and maps of geographic distribution based on examined material. The monophyly of Macrocoeloma was demonstrated after exclusion of Pericera heptacantha and P. septemspinosa. The monotypic genus Thersandrus Rathbun, 1897 is a sister group of Macrocoeloma, followed by the new genus proposed ... (Complete abstract click electronic access below) / Doutor

Thesis (PhD)--University of Stellenbosch, 2002. / ENGLISH ABSTRACT: In the present study, the systematic status, aspects of the evolutionary biology and phylogenetic relationships among species of the African freshwater crab genus Potamonautes in South Africa are examined. Systematic research between allopatric populations of P. brincki, using allozyme and morphometric data has revealed the existence of a new undescribed freshwater crab species occurring in mountain streams of the Cape Peninsula. This species is described in the present study. In addition, the diagnostic value of carapace dentition patterns in the taxonomy of freshwater crabs is explored among two toothed river crab species from South Africa. The latter study utilized P. warreni and P. unispinus where considerable variation in the dentition pattern of the former species has been recorded. Fixed differences in allozyme loci demonstrated that these two taxa should indeed be considered separate, yet closely related species, while the morphometric data failed to reveal this taxonomic separation. The holotype of P. warreni is re-described. The relationship of hybrid taxa between P. depressus and P. clarus populations are investigated. Evident from this study is that populations that occur equidistant from the two parental taxa have undergone extensive introgressive hybridization. Considering the pronounced sequence divergence and the occurrence of fixed allozyme loci between populations, it is postulated that the hybrid populations should be considered to be on a unique evolutionary trajectory worthy of conservation. The population genetic structure of P. calcaratus is examined as this species is unique in its occupation of water holes. Results demonstrate that the genetic population structure is the result of recent colonization and moderate gene flow among populations. Phylogenetic relationships between the southern African freshwater crab fauna is investigated with the use of sequence data from two mitochondial genes (12 S rRNA and 16 S rRNA), allozymes and morphology in an attempt to firstly, test the usefulness of freshwater crabs as biogeographic indicators, secondly to explore the relationship among hybrid taxa, and thirdly to examine Bott's (1955) subgeneric divisions. Results demonstrated that freshwater crabs can be used as biogeographic indicators, that hybrid taxa are phylogenetic ally closely related and that Bott's subgeneric divisions have no systematic basis. Among the three data sets, the sequence data provided the best resolution, while the phylogenetic inferences derived from the allozyme data and the morphology was limited. / AFRIKAANSE OPSOMMING: In hierdie studie word die sistematiek, aspekte van die evolusionêre biologie en filogenetiese verwantskappe tussen spesies van die varswater krap genus Potamonautes ondersoek in Suid Afrika. Navorsing op geografies geisoleerde populasies van P. brincki word met behulp van allosieme en morfometriese data ondersoek en dui daarop dat daar 'n nuwe onbeskryfde spesie op die berge van die Kaapse Skiereiland voorkom. Die nuwe spesies word beskryf in hierdie studie. Die diagnostiese waarde van tand patrone in varswater krappe word tussen twee spesies P. warreni en P. unispinus ondersoek. Genetiese data dui daarop dat alhoewel P. warreni morfologies baie naverwant is aan P. unispin us, is genoegsame verskille in allosiem lokusse wat daarop dui dat die twee taksa volwaardige spesies is. Die holotipe van P. warreni word herbeskryf. Die verwantkap tussen populasies van twee hibried taksa, P. depressus en P. clarus, word ondersoek. Resultate van hierdie studie dui daarop dat noemenswaardige verskille voorkom tussen die twee hibridie taxa en dat die hibriede populasies geneties verskillend is. 'n Argument word aangevoer vir die beskerming van hibriede taksa. Die populasie genetika van P. calcaratus word ondersoek en vergelyk met vorige studies. Die data dui daarop dat minimale geen vloei tusses populasies is en dat die populasie struktuur waarskynlik die resultaat is van onlangse kolonisasie. Die filogenetiese verwantskap tussen die suider Afrikaanse krappe word ondersoek met DNA, allosieme en morfologiese karakters met drie hoofdoele. Eerstens om die gebruik van varswater krappe as biografiese indikatore te toets. Tweedens om die verwantskap van hibriede taksa te ondersoek, en derdens om die status van Bott (1955) se subgenera te bepaal. Resultate dui daarop aan dat varswater krappe wel gebruik kan word as biografiese indikatore. Hibridieserende taxa naverwant is derdens en dat Bott se subgenera geen taksonomiese basis het nie. Die DNA data het die beste resolusie gebied vir die filogenetiese vrae, terwyl die allosieme en morfologiese data 'n laer resolusie bedied het, en meer beperk was.

The purpose of this study was to examine the masking preferences of the spider crab, Notomithrax ursus. The algal composition of the mask in the natural habitat at Kaikoura was examined to determine the general rules the crab follows when decorating itself. The effects of size and sex on the mask composition were examined, as well as determining how the composition of the mask varies by body part. The preference of the crabs was further examined through the use of choice and background change experiments in the laboratory. It was determined that the preference of certain types of algae for mask material is not entirely dependent on their relative abundance in the environment. Possible explanations for this behaviour are given.

I examine some of the ecological and evolutionary implications of body size in hermit crabs, with special emphasis on the upper intertidal species Clibanarius digueti. In Chapter 1 I show that body size had a far greater effect than species identity on desiccation tolerance for shell-less individuals of C. digueti, Paguristes anahuacus, Pagurus lepidus, and Phimochirus roseus. In contrast with other intertidal taxa, there was no correlation between the upper tidal limit of a species and the expected desiccation tolerance of an average-sized, shell-less individual of that species. This suggests that the gastropod shell that normally houses the hermit crab is sufficient to eliminate desiccation as a community-structuring force in this guild. Clibanarius digueti exhibits strong sexual dimorphism in body size, with almost no overlap in size between adult males and females. In Chapter 2 I show that sexual differences in the intensity of selection on size favor this dimorphism. Specifically, male mating success depended more strongly on body size than did female fecundity. In fact, the rate of increase in fecundity with body size equalled the lowest previously recorded for decapod crustaceans, suggesting that sexual size dimorphism in this species may depend more on weak fecundity selection on females than on strong sexual selection on males. Documenting contemporary selection on a character, however, is not the same as documenting that selection caused the character to evolve. Chapter 3 presents the first empirical test in a single species (C. digueti) of the hypothesis that sexual size dimorphism represents an evolutionary response to sexual differences in selection on size. The test is based on a general model that predicts crab body size as a function of shell limitations, shell fit and body size. Both males and females occupied optimally sized shells of non-preferred species, but the greater the desirability of a shell species, the greater the tendency for males to occupy tighter-fitting shells than females. Males also apparently suffere higher mortality than similarly-sized females. According to the general model, these results agree with the hypothesis that differential selection is causally involved in the evolution of sexual size dimorphism, and contradict the alternative hypothesis that energetic constraints on females produce the dimorphism.

Masking or decorator crabs, conceal themselves partially through camouflage, by selecting or indiscriminately attaching materials from their environment to their exoskeleton. Functional aspects of decorating behavior and morphology in this group have not been documented. Using Microphrys bicornutus as a model species, this dissertation demonstrates clearly that decorating is an advantageous phenotype that has evolved to serve several functions. Decorating is a complex behavior that begins when a crab approaches an algal substrate and results in the attachment of algae to hooked setae on the exoskeleton. Once decorated, crabs remain motionless on the substrate until disturbed or until another behavior is initiated. This was confirmed for M. bicornutus, as crabs spent a significant amount of time feeding, remaining motionless, picking, and walking when compared to decorating. Crabs displayed agonistic behaviors during encounters with conspecifics conspecifics. These included both active aggressive behavior and display behavior. Crabs showed a decrease in motility during these encounters, helping maintain dispersed distributions, thereby decreasing intrsapecific encounters in the field. Trials were done to determine the effect of conspecifics, predators and feeding preferences on algal utilization. M. bicornutus showed a significant decrease in the amount of algae used for decoration in the highest density trials (i.e., 4 and 8 crabs). Agonistic displays and aggressive behavior between these crabs likely affected the time available for decorating. Decorated crabs isolated from an algal substrate were more likely to survive in the presence of either of two sympatric fish predators. Thus, being protected by the algal decoration on their exoskeletons. Trials also showed a parallel between algal consumption and algal materials used for decoration. In addition to its protective function, algae used by M. bicornutus for decoration simultaneously serve as short term food supplies for the crabs. Eleven morphologically complex structures were identified and mapped on the exoskeleton. Hooked setae were the primary structures used to attach algae to the crab’s body. Ten additional setal structures were present, including two novel types of setae. On the basis of location and morphological variation exhibited among these latter structures, a primary sensory function may be inferred. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2013.

Crustaceans are ubiquitous in the world’s oceans and include species ranged in size from < 1 mm to > 1 m. Information on the natural diet of marine crustaceans, especially the small crustaceans such as copepods, is usually obtained by measuring gut content microscopically or by the use of electronic particle counters, by microscopic examination of gut contents and fecal pellets, and by the use of stable isotopes or taxon-specific pigment markers. Unfortunately, most of these methods involve conducting feeding experiments in artificial laboratory condition, require a high level of taxonomic expertise, and provide only coarse information on food types that are digestion-resistant. Increasingly over the past decade, DNA-based methods have been used to study the natural diet of small marine organisms such as molluscan larva and the lobster larva with high taxonomic resolution. / In this thesis, the diets of two marine crustaceans are investigated. The small calanoid copepod Calanus sinicus (2.5−3.5 mm), one of the animals studied in this thesis, is a dominant member of the marine zooplankton in the continental shelf waters of China and the northwest Pacific Ocean. Copepods of the genus Calanus are generally considered to be herbivorous although information on the natural diet of C. sinicus is scarce. / Another marine crustacean studied in this thesis is the hydrothermal crab Xenograpsus testudinatus. This crab is endemic to the shallow-water hydrothermal vents of Kueishan Island in the northeastern corner of Taiwan. The extreme environment inhabited by X. testudinatus is unsuitable for most marine organisms due to discharge of hot and acidic water with high content of sulphur. Although the diet of X. testudinatus has been studied by several investigations, the taxonomic resolution of the dietary information is poor. / Accurate information of the diet and feeding habit of a species provides the basis for understanding its role in aquatic food webs. In my thesis, the natural diets of the marine copepod C. sinicus from Hong Kong and Taiwan and the hydrothermal vent crab X. testudinatus were investigated using Illumina sequencing of the prey DNA in the gut content. Variable regions of the 18S and 16S rRNA genes in the gut contents are amplified using DNA extracted from gut contents to determine the composition of eukaryotes and prokaryotes in the diet of the marine crustacean. The diet of X. testudinatus are compared to those of the mangrove crabs Perisesarma bidens. / Gelatinous zooplankton including Hydrozoa and unclassified Ctenophora are very common in the gut contents of C. sinicus from both Hong Kong and Taiwan. C. sinicus from Hong Kong contains diatoms and dinoflagellates, while C. sinicus from northern Taiwan also feeds on Anthozoa, Ascidiacea and Malacostraca. Unclassified Proteobacteria and unclassified bacteria are common in C. sinicus from both Hong Kong and Taiwan. Cyanobacteria, mainly Synechococcus, are only found in C. sinicus from Taiwan. My results show that C. sinicus can feed omnivorously on a diverse assemblage of phytoplankton and zooplankton. / The diet of X. testudinatus differs from that of P. bidens. While P. bidens feeds mainly on Magnoliopsida plant, X. testudinatus feeds on a diverse assemblage of organisms including algae, fishes, bivalves, copepods and anthozoans. Although soil bacteria such as Rodobacteraceae and cyanobacteria including Oscillatoriphycidae occur in the gut contents of both crabs, Mycoplasmataceae and Helicobacteraceae, which are suspected to be gut probiotic bacteria, are only found in the vent crabs. My findings suggest that both X. testudinatus and P. bidens are scavengers. / In short, the DNA-based method can provide detailed information on the natural diets of marine crustaceans and provide accurate information on the trophic role of the marine crustaceans in the food webs. / 甲殻類動物在海洋上是很常見的。牠們的體型大小也有很大的差異(由< 1毫米到 > 1米)。有關海洋甲殻類動物食性研究特別是一些細小甲殻類動物例如橈腳類動物通常都是利用電子計量器或以肉眼在顯微鏡下計算，利用電子顯微鏡去鑑定腸及糞便中的食物殘滓及利用穩定同位素或物種獨有的色素去鑑定。不過，這些方法包括實驗室餵食測試需要熟練的鑑定技巧而且這些方法只能夠提供粗略的資訊。例如只限於會經消化後留下硬塊的食物。雖然如此，最近有研究成功利用DNA鑑定的方法去找出一些細小海洋甲殻類動物例如龍蝦及軟體動物的幼體的食性。 / 這篇論文主要研究兩種海洋甲殻類動物的野外食物。其中一種研究對象，細小的橈腳類動物中華哲水蚤 (2.5−3.5毫米)，在中國沿岸海域及西北太平洋是很常見的。雖然有關於中華哲水蚤在食性資料不多，但是哲水蚤類的動物一般被認為是草食性。 / 這篇論文的另一研究對象是烏龜怪方蟹。牠在位於台灣東北部的龜山島的淺水熱噴泉是很常見的。在淺水熱噴泉的生境，由於經常有酸性高溫及含有高濃度硫磺的水噴出，所以那裡是被認為不適合生物居住的。雖然烏龜怪方蟹的食性也有被研究過，但有關牠們的攝食的物種鑑定還是不夠詳細。 / 準確的有關生物的食性的資料可以幫助我們了解該生物在海洋食物網中角色。有見及此，在這篇論文中主要會利用DNA鑑定及Illumina定序技術來研究來自香港及台灣的中華哲水蚤及在淺水熱噴泉的烏龜怪方蟹的食性。在實驗中，腸道中的DNA的18S及16S rRNA基因中DNA序列差異大的區域會被用來鑑定腸道中的有核生物及原生生物。居住在紅樹林的雙齒近相手蟹的攝食也會用來跟烏龜怪方蟹比較。 / 啫哩狀的浮游動物比如水息蟲類動物及櫛水母來自香港及台灣的中華哲水蚤的腸道中是很常見的。在來自香港的中華哲水蚤腸道中找到了硅藻及甲藻，而在來自台灣的中華哲水蚤的腸道中卻找到珊瑚綱動物，海蛸和軟甲綱動物。在來自香港及台灣的中華哲水蚤的腸道中找到的原核生物為不能鑑定的細菌及不能鑑定的變形菌。藍綠藻主要為聚球藻只有在來自台灣的中華哲水蚤的腸道中找到。研究的結果顯示中華哲水蚤是雜食性及攝食很多不同類型的浮游生物。 / 研究結果顯示烏龜怪方蟹所食的食物跟雙齒近相手蟹很不同。雙齒近相手蟹主要攝食雙子葉植物綱植物，而烏龜怪方蟹所吃的食物是高生物多樣性的包括藻類，魚，雙殻綱動物，橈腳類動物及珊瑚綱動物。土壤細菌比如紅桿菌科細菌及藍綠藻都可以烏龜怪方蟹及雙齒近相手蟹的腸道及胃道中找到，而可能是腸道原生細菌的枝原體科細菌及螺旋杆菌科細菌只能夠在烏龜怪方蟹的腸道中找到。研究結果顯示烏龜怪方蟹及雙齒近相手蟹都是拾荒者。 / 總括而言，利用DNA去研究動物食性的方法可以提供更多有關海洋甲殻類動物食性的詳細資料及提供準確的有關海洋甲殻類動物食性層次的資料。 / Ho, Tsz Wai. / Thesis M.Phil. Chinese University of Hong Kong 2015. / Includes bibliographical references (leaves 65-85). / Abstracts also in Chinese. / Title from PDF title page (viewed on 12, October, 2016). / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only.