Zoological Letters最新文献

{"title":"Structural and bio-functional assessment of the postaxillary gland in <i>Nidirana pleuraden</i> (Amphibia: Anura: Ranidae).","authors":"Yuzhou Gong, Yiwei Zeng, Puyang Zheng, Xun Liao, Feng Xie","doi":"10.1186/s40851-020-00160-w","DOIUrl":"10.1186/s40851-020-00160-w","url":null,"abstract":"<p><strong>Background: </strong>Owing to their incomplete adaptation to the terrestrial environment, amphibians possess complex cutaneous glandular systems. The skin glands not only regulate water loss and respiratory gas and salt exchange, but are also involved in defense against predators and microorganisms, social communication, and reproduction. These glands are distributed throughout the integument, but can accumulate in specific regions, forming visible outgrowths known as macroglands. Some macroglands are sexually dimorphic and mediate intersexual communication and reproductive success. The postaxillary gland is a sexually dimorphic macrogland in <i>Nidirana pleuraden</i>. Its biological function and its morphological and histochemical characteristics are unclear. In the present study, we describe the structure and ultrastructure of the postaxillary gland, and explore its main function.</p><p><strong>Results: </strong>The postaxillary gland has a thinner epidermis than the dorsal region of <i>N. pleuraden</i>. In addition to ordinary serous glands (OSG), type I and II mucous gland (I MG & II MG), a type of specialized mucous gland (SMG) is also found to constitute the postaxillary gland. The SMG is larger than other gland types, and consists of high columnar mucocytes with basal nuclei arranged radially toward a lumen. SMGs are positive to periodic acid-Schiff stain and stained blue in Masson's trichrome stain. A discontinuous myoepithelial sheath lacking innervation encircles SMG mucocytes, and the outlets of such glands are X- or Y-shaped. Transmission electron microscopy reveals abundant secretory granules in SMG, which are biphasic, composed of an electron-opaque outer ring and a less electron-dense core. Lipid droplets, and organelles, such as rough endoplasmic reticulum and Golgi stacks, are located in the supranuclear cytoplasm of the mucocytes in SMG. Female <i>N. pleuraden</i> exhibits chemotaxis toward homogenate of the postaxillary gland, but male does not. On treatment with trypsin, this sexual attraction disappears.</p><p><strong>Conclusions: </strong>The postaxillary gland of <i>N. pleuraden</i> is a male-specific macrogland that consists primarily of SMGs, together with OSGs, I MGs and II MGs. Other than their extremely large size, SMGs structurally and histochemically resemble many reported specialized gland types in amphibian sexually dimorphic skin glands. Secretions of the postaxillary gland are proteinaceous sexual pheromones, which are believed to attract females at male calling intermissions.</p>","PeriodicalId":54280,"journal":{"name":"Zoological Letters","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2020-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7275488/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38027466","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evidence from ileum and liver transcriptomes of resistance to high-salt and water-deprivation conditions in camel.","authors":"Dong Zhang,&nbsp;Jing Pan,&nbsp;Huanmin Zhou,&nbsp;Yu Cao","doi":"10.1186/s40851-020-00159-3","DOIUrl":"https://doi.org/10.1186/s40851-020-00159-3","url":null,"abstract":"<p><p>Camels have evolved various resistance characteristics adaptive to their desert habitats. In the present study, we used high-throughput sequencing to investigate stress-induced alternative splicing events as well as different genes involved in resistance to water deprivation and salt absorption in the ileum and liver in <i>Camelus bactrianus</i>. Through association analyses of mRNA, miRNA and lncRNA, we sought to explicate how camels respond to high salt and water scarcity conditions. There were two modes by which genes driven by alternative splicing were enriched to molecular functions, invoking of which was potentially fixed by organ and stress types. With qRT-PCR detection, the differentially expressed <i>MUC6</i>, <i>AQP5</i>, <i>LOC105076960</i>, <i>PKP4</i>, <i>CDH11</i>, <i>TENM1, SDS</i>, <i>LOC105061856</i>, <i>PLIN2</i> and <i>UPP2</i> were screened as functionally important genes, along with miR-29b, miR-484, miR-362-5p, miR-96, miR-195, miR-128 and miR-148a. These genes contributed to cellular stress resistance, for instance by reducing water loss, inhibiting excessive import of sodium, improving protective barriers and sodium ion homeostasis, and maintaining uridine content. The underlying competing endogenous RNAs referred to LNC001664, let-7e and <i>LOC105076960</i> mRNA in ileum, and LNC001438, LNC003417, LNC001770, miR-199c and <i>TENM1</i> mRNA in liver. Besides competent interpretation to resistance, there may be inspirations for curing human diseases triggered by high-salt intake.</p>","PeriodicalId":54280,"journal":{"name":"Zoological Letters","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2020-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s40851-020-00159-3","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38027467","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Natural selection, selective breeding, and the evolution of resistance of honeybees (<i>Apis mellifera)</i> against <i>Varroa</i>.","authors":"Jacques J M van Alphen,&nbsp;Bart Jan Fernhout","doi":"10.1186/s40851-020-00158-4","DOIUrl":"https://doi.org/10.1186/s40851-020-00158-4","url":null,"abstract":"<p><p>We examine evidence for natural selection resulting in <i>Apis mellifera</i> becoming tolerant or resistant to <i>Varroa</i> mites in different bee populations. We discuss traits implicated in <i>Varroa</i> resistance and how they can be measured. We show that some of the measurements used are ambiguous, as they measure a combination of traits. In addition to behavioural traits, such as removal of infested pupae, grooming to remove mites from bees or larval odours, small colony size, frequent swarming, and smaller brood cell size may also help to reduce reproductive rates of <i>Varroa</i>. Finally, bees may be tolerant of high <i>Varroa</i> infections when they are resistant or tolerant to viruses implicated in colony collapse. We provide evidence that honeybees are an extremely outbreeding species. Mating structure is important for how natural selection operates. Evidence for successful natural selection of resistance traits against <i>Varroa</i> comes from South Africa and from Africanized honeybees in South America. Initially, <i>Varroa</i> was present in high densities and killed about 30% of the colonies, but soon after its spread, numbers per hive decreased and colonies survived without treatment. This shows that natural selection can result in resistance in large panmictic populations when a large proportion of the population survives the initial <i>Varroa</i> invasion. Natural selection in Europe and North America has not resulted in large-scale resistance. Upon arrival of <i>Varroa</i>, the frequency of traits to counter mites and associated viruses in European honey bees was low. This forced beekeepers to protect bees by chemical treatment, hampering natural selection. In a Swedish experiment on natural selection in an isolated mating population, only 7% of the colonies survived, resulting in strong inbreeding. Other experiments with untreated, surviving colonies failed because outbreeding counteracted the effects of selection. If loss of genetic variation is prevented, colony level selection in closed mating populations can proceed more easily, as natural selection is not counteracted by the dispersal of resistance genes. In large panmictic populations, selective breeding can be used to increase the level of resistance to a threshold level at which natural selection can be expected to take over.</p>","PeriodicalId":54280,"journal":{"name":"Zoological Letters","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2020-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s40851-020-00158-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"37984379","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cellular and molecular aspects of oocyte maturation and fertilization: a perspective from the actin cytoskeleton.","authors":"Luigia Santella, Nunzia Limatola, Jong Tai Chun","doi":"10.1186/s40851-020-00157-5","DOIUrl":"10.1186/s40851-020-00157-5","url":null,"abstract":"<p><strong>Abstract: </strong>Much of the scientific knowledge on oocyte maturation, fertilization, and embryonic development has come from the experiments using gametes of marine organisms that reproduce by external fertilization. In particular, echinoderm eggs have enabled the study of structural and biochemical changes related to meiotic maturation and fertilization owing to the abundant availability of large and transparent oocytes and eggs. Thus, in vitro studies of oocyte maturation and sperm-induced egg activation in starfish are carried out under experimental conditions that resemble those occurring in nature. During the maturation process, immature oocytes of starfish are released from the prophase of the first meiotic division, and acquire the competence to be fertilized through a highly programmed sequence of morphological and physiological changes at the oocyte surface. In addition, the changes in the cortical and nuclear regions are essential for normal and monospermic fertilization. This review summarizes the current state of research on the cortical actin cytoskeleton in mediating structural and physiological changes during oocyte maturation and sperm and egg activation in starfish and sea urchin. The common denominator in these studies with echinoderms is that exquisite rearrangements of the egg cortical actin filaments play pivotal roles in gamete interactions, Ca²⁺ signaling, exocytosis of cortical granules, and control of monospermic fertilization. In this review, we also compare findings from studies using invertebrate eggs with what is known about the contributions made by the actin cytoskeleton in mammalian eggs. Since the cortical actin cytoskeleton affects microvillar morphology, movement, and positioning of organelles and vesicles, and the topography of the egg surface, these changes have impacts on the fertilization process, as has been suggested by recent morphological studies on starfish oocytes and eggs using scanning electron microscopy. Drawing the parallelism between vitelline layer of echinoderm eggs and the zona pellucida of mammalian eggs, we also discuss the importance of the egg surface in mediating monospermic fertilization.</p><p><strong>Graphical abstract: </strong></p>","PeriodicalId":54280,"journal":{"name":"Zoological Letters","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2020-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7158055/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"37855355","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"First observation of larval oarfish, <i>Regalecus russelii</i>, from fertilized eggs through hatching, following artificial insemination in captivity.","authors":"Shin-Ichiro Oka,&nbsp;Masaru Nakamura,&nbsp;Ryo Nozu,&nbsp;Kei Miyamoto","doi":"10.1186/s40851-020-00156-6","DOIUrl":"https://doi.org/10.1186/s40851-020-00156-6","url":null,"abstract":"<p><strong>Background: </strong>Little is known about the life history of oarfish of the genus <i>Regalecus</i>, although it is a famous deep-sea fish and an apparent origin of sea serpent legends. We successfully performed artificial insemination using a recently dead pair of sexually mature individuals. We report for the first time development from fertilized eggs to early larvae in the Lampridiformes.</p><p><strong>Results: </strong>Eggs required 18 days of development from fertilization to hatching under 20.5-22.5 °C conditions. Oarfish larvae had similar morphological features as other lampridiform larvae hatched in the ocean. Larvae typically faced downward and swam using pectoral fins; they frequently opened their mouths. This mouth-opening behavior and swimming ability were both consistent with osteological development. The larvae did not eat and died four days after hatching.</p><p><strong>Conclusions: </strong>This is the first successful instance of artificial insemination and hatching in the oarfish, as well as the first reliable morphological and behavioral description of lampridiform larvae.</p>","PeriodicalId":54280,"journal":{"name":"Zoological Letters","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2020-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s40851-020-00156-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"37837099","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Structure and development of the complex helmet of treehoppers (Insecta: Hemiptera: Membracidae).","authors":"Haruhiko Adachi,&nbsp;Keisuke Matsuda,&nbsp;Kenji Nishida,&nbsp;Paul Hanson,&nbsp;Shigeru Kondo,&nbsp;Hiroki Gotoh","doi":"10.1186/s40851-020-00155-7","DOIUrl":"https://doi.org/10.1186/s40851-020-00155-7","url":null,"abstract":"<p><p>Some insects possess complex three-dimensional (3D) structures that develop under the old cuticle prior to the last imaginal molt. Adult treehoppers (Insecta: Hemiptera: Auchenorrhyncha: Membracidae) have one such complex 3D structure, known as a helmet, on their dorsal side. The adult helmet likely forms inside the nymphal pronotum during the final instar nymphal stage. Previous morphological studies have reported that the adult helmet is a large, bi-layered, plywood-like structure, whereas the nymphal pronotum is a monolayer, sheath-like structure. The adult helmet is much larger than nymphal helmet. Thus, the emergence of the adult helmet involves two structural transitions: a transition from a monolayer, sheath-like pronotum to a bi-layer, plywood-like helmet, and a transition in size from small to large. However, when, how, and in what order these transitions occur within the nymphal cuticle is largely unknown. To determine how adult helmet development occurs under the nymphal cuticle, in the present study we describe the morphology of the final adult helmet and investigate developmental trajectories of the helmet during the final instar nymphal stage. We used micro-CT, scanning electron microscope and paraffin sections for morphological observations, and used <i>Antianthe expansa</i> as a model species. We found that the structural transition (from monolayer, sheath-like structure to bi-layer, roof-like structure) occurs through the formation of a \"miniature\" of the adult helmet during the middle stage of development and that subsequently, extensive folding and furrows form, which account for the increase in size. We suggest that the making of a \"miniature\" is the key developmental step for the formation of various 3D structures of treehopper helmets.</p>","PeriodicalId":54280,"journal":{"name":"Zoological Letters","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2020-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s40851-020-00155-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"37699048","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A new redescription of <i>Richtersius coronifer</i>, supported by transcriptome, provides resources for describing concealed species diversity within the monotypic genus <i>Richtersius</i> (Eutardigrada).","authors":"Daniel Stec, Łukasz Krzywański, Kazuharu Arakawa, Łukasz Michalczyk","doi":"10.1186/s40851-020-0154-y","DOIUrl":"10.1186/s40851-020-0154-y","url":null,"abstract":"<p><p><i>Richtersius coronifer</i>, the nominal species for the family Richtersiidae and a popular laboratory model, exemplifies a common problem in modern tardigrade taxonomy. Despite undeniable progress in the field, many old and incomplete descriptions of taxa hinder both species delimitation and the estimation of species diversity and distribution. Although for over a century this species has been recorded throughout the world, recent research indicates that records to date are likely to represent a species complex rather than a single cosmopolitan species. However, in order to recognise and name species diversity within the complex, an integrative redescription of the nominal species is first needed. Here, we describe an <i>R. coronifer</i> population collected from Spitsbergen, i.e., one of the two localities mentioned in the original description, with detailed morphological and morphometric data associated with standard DNA sequences of four standard genetic markers (18S rRNA, 28S rRNA, ITS-2, and COI) and supported by transcriptome sequencing. We propose replacement of the neotype designated in 1981 by Maucci and Ramazzotti, as it is impossible to verify whether the existing neotype is conspecific with specimens studied by Richters in 1903 and 1904. Finally, using newly obtained cytochrome c oxidase subunit I (COI) sequences of populations from Spitsbergen, Italy, Poland, and Greece together with sequences deposited in GenBank (China, Greenland, Italy, Mongolia), we performed genetic species delimitation, which indicated seven distinct potential species within the genus <i>Richtersius</i>, in addition to the nominal taxon. This study marks a starting point for further research on the taxonomy of and species diversity within the genus. Moreover, this work has the potential to be the first tardigrade redescription to provide both genetic barcodes and a transcriptome of the species in question.</p>","PeriodicalId":54280,"journal":{"name":"Zoological Letters","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2020-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7003491/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"37635313","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Long-term monitoring reveals invariant clutch size and unequal reproductive costs between sexes in a subtropical lacertid lizard.","authors":"Jhan-Wei Lin,&nbsp;Ying-Rong Chen,&nbsp;Tsui-Wen Li,&nbsp;Pei-Jen L Shaner,&nbsp;Si-Min Lin","doi":"10.1186/s40851-019-0152-0","DOIUrl":"https://doi.org/10.1186/s40851-019-0152-0","url":null,"abstract":"<p><p>Based on 20,000 records representing <i>c</i>. 11,000 individuals from an 8-year capture-mark-recapture (CMR) study, we tested and confirmed a new case of invariant clutch size (ICS) in a sexually dichromatic lacertid lizard, <i>Takydromus viridipunctatus</i>. In the grassland habitat of the early succession stage, females showed strictly low and invariant clutch size, multiple clutches in a breeding season, high reproductive potential, and annual breeding cycles that correspond to the emergence of male courtship coloration. The hatchlings mature quickly, and join the adult cohort for breeding within a few months, whereas adults show low survival rates and a short lifespan, such that most die within one year. Mortality increased in both sexes during the breeding season, especially in females, indicating an unequal cost of reproduction in survival. These life history characters may be explained by two non-exclusive hypotheses of ICS-arboreal hypothesis and predation hypothesis-within the ecological context of their habitat. Our study highlights a confirmed case of ICS, which adapts well to this <i>r</i>-selected grassland habitat that experiences seasonal fluctuation and frequent disturbance.</p>","PeriodicalId":54280,"journal":{"name":"Zoological Letters","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2020-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s40851-019-0152-0","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"37529815","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A right whale (Mysticeti, Balaenidae) from the Pleistocene of Taiwan.","authors":"Cheng-Hsiu Tsai,&nbsp;Chun-Hsiang Chang","doi":"10.1186/s40851-019-0153-z","DOIUrl":"https://doi.org/10.1186/s40851-019-0153-z","url":null,"abstract":"<p><p>Current patterns of biological distribution result from the deep past. Of particular interest, some closely related species appear at high latitudes of both hemispheres, but not in between, a pattern known as antitropical distribution. However, the timing, pathway, and drivers of antitropical distributions remain mostly unknown. Here we describe a new fossil, a left tympanic bulla (part of the ear bones), from the Middle/Late Pleistocene (0.78-0.01 mya, but not excluding the possibility of Holocene in age, as the specimen was dredged from the sea bottom and the geological horizon remains uncertain) of Taiwan. The tympanic bulla is diagnostic in baleen whales, and this specimen shows morphological features that are identical to extant <i>Eubalaena</i>, including: relatively large size (the anteroposterior length is 117 mm); rectangular outline in medial view; short anterior lobe, judging from the remaining of the lateral furrow; squared anterior margin; prominent transverse crease on the involucrum; transversely compressed in anterior view; well-developed and rounded outer lip; and parallel involucral and main ridges. Although incomplete, the morphological characters and overall similarity to extant <i>Eubalaena</i> allow a reliable taxonomic assignment to <i>Eubalaena</i> sp. The occurrence of a Pleistocene <i>Eubalaena</i> on the southern margin of the western North Pacific is the first balaenid fossil evidence indicative of the biotic interchange between two hemispheres leading to the origin of antitropical distribution in the Pleistocene; alternatively, this specimen might merely represent an extra-limital record of the North Pacific <i>Eubalaena</i>. Furthermore, this find suggests that the <i>Eubalaena</i> interchange, being one of the largest species displaying antitropical distribution pairs in the history of life, likely took place along the western Pacific. Notably, this does not preclude the <i>Eubalaena</i> interchange from other routes, such as the eastern Pacific or the Atlantic Ocean, and future finds should test the scenario for the biotic interchange between Northern and Southern Hemispheres of <i>Eubalaena</i>.</p>","PeriodicalId":54280,"journal":{"name":"Zoological Letters","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2019-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s40851-019-0153-z","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"37502535","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Histaminergic interneurons in the ventral nerve cord: assessment of their value for Euarthropod phylogeny.","authors":"Maite Maurer,&nbsp;Janina Hladik,&nbsp;Thomas M Iliffe,&nbsp;Torben Stemme","doi":"10.1186/s40851-019-0151-1","DOIUrl":"https://doi.org/10.1186/s40851-019-0151-1","url":null,"abstract":"<p><p>Despite numerous approaches to the resolution of euarthropod phylogeny, mainly based on modern sequence information and traditional external morphology, the resulting hypotheses are often contradictory and leave many questions about euarthropod evolution unanswered. The comparison of developmental and structural aspects of the nervous system has shown to be a valuable contribution to the assessment of current phylogenetic hypotheses. One promising approach for the generation of new character sets is the morphology of transmitter systems and the discovery of individually identifiable neurons, which allow phylogenetic comparisons on the single cell level. In this context, the serotonin transmitter system has been investigated to a considerable degree. Studies to date have yielded important stimuli to our understanding of euarthropod relationships and the evolution of their nervous systems. However, data on other transmitter systems remain fragmented, and their value with respect to phylogenetic questions remains speculative. The biogenic amine histamine is a promising transmitter; a substantial amount of data has been reported in the literature and the homology of some histaminergic neurons has been suggested. Here, we present a comprehensive review of histaminergic neurons in the ventral nerve cord of Euarthropoda. Using immunocytochemical labeling of histamine combined with confocal laser-scanning microscopy, we investigated the transmitter system in phylogenetically relevant taxa, such as Zygentoma, Remipedia, Diplopoda, and Arachnida. By reconstructing ground patterns, we evaluated the significance of this specific character set for euarthropod phylogeny. With this approach, we identified a set of neurons, which can be considered homologous within the respective major taxon. In conclusion, the histaminergic system contains useful information for our understanding of euarthropod phylogeny, supporting the proposed clades Tetraconata and Mandibulata. Furthermore, this character set has considerable potential to help resolve relationships within the major clades at a deeper level of taxonomy, due to the considerable variability in neurite morphology.</p>","PeriodicalId":54280,"journal":{"name":"Zoological Letters","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2019-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s40851-019-0151-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"37502534","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}