DOCSLIB.ORG

Microsatellite Discovery in an Insular Amphibian

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Microsatellite Discovery in an Insular Amphibian 1 1 Methods and Resource Article 2 3 Microsatellite discovery in an insular amphibian (Grandisonia 4 alternans) with comments on cross-species utility and the accuracy of 5 locus identification from unassembled Illumina data 6 7 Eleanor A. S. Adamson1 • Anwesha Saha1, 2, 3 • Simon T. Maddock1, 2, 4 • Ronald 5 1 1 8 A. Nussbaum • David J. Gower • Jeffrey W. Streicher 9 10 11 1Department of Life Sciences, The Natural History Museum, London SW7 5BD, UK 12 13 2Department of Genetics, Evolution and Environment, University College London, 14 London WC1E 6BT, UK 15 16 3Ashoka Trust for Research of Ecology and the Environment, Bangalore, India 17 18 4Department of Animal Management, Reaseheath College, Nantwich, CW5 6DF, UK. 19 20 5Department of Ecology and Evolutionary Biology, University of Michigan, Ann 21 Arbor, Michigan 48109, USA 22 23 _____________________________________________________________________ 24 Eleanor A. S. Adamson and Anwesha Saha have contributed equally to this work. 25 _____________________________________________________________________ 26 27 Corresponding Author: Jeffrey W. Streicher ([email protected]) 28 29 Submitted to Conservation Genetics Resources 30 5 Figures, 2 Tables, 1 Table Online 31 Word counts: Abstract, 250 words [250 max]; Main text/references, 4,997 [6000 max] 32 33 2 34 35 Abstract The Seychelles archipelago is unique among isolated oceanic islands 36 because it features an endemic radiation of caecilian amphibians (Gymnophiona). In 37 order to develop population genetics resources for this system, we identified 38 microsatellite loci using unassembled Illumina MiSeq data generated from a genomic 39 library of Grandisonia alternans, a species that occurs on multiple islands in the 40 archipelago. Applying a recently described method (PALFINDER) we identified 41 8,001 microsatellite loci that were potentially informative for population genetics 42 analyses. Of these markers, we screened 60 loci using five individuals, directly 43 sequenced several amplicons to confirm their identity, and then used eight loci to 44 score allele sizes in 64 G. alternans individuals originating from five islands. A 45 number of these individuals were sampled using non-lethal methods, demonstrating 46 the efficacy of non-destructive molecular sampling in amphibian research. Although 47 two loci satisfied our criteria as diploid, neutrally evolving loci with the statistical 48 power to detect population structure, our success in identifying reliable loci was very 49 low. Additionally, we discovered some issues with primer redundancy and differences 50 between Illumina and Sanger sequences that suggest some Illumina-inferred loci are 51 invalid. We investigated cross-species utility for eight loci and found most could be 52 successfully amplified, sequenced and aligned across other genera/species of 53 caecilians from the Seychelles. Thus, our study in part supported the validity of using 54 PALFINDER with unassembled reads for microsatellite discovery within and across 55 species, but importantly identified major limitations to applying this approach to 56 small datasets (ca. 1 million reads) and loci with small tandem repeat sizes. 57 58 Keywords caecilians • cross amplification • Gymnophiona • Hypogeophis 59 •Indotyphlidae • Praslinia • Seq-to-SSR approach • simple sequence repeats 60 3 61 Introduction 62 63 Microsatellites or simple sequence repeats (SSR) are one of the most widely used 64 tools in population genetics and conservation biology. As costs associated with high- 65 throughput Next Generation DNA sequencing (NGS) have decreased, microsatellite 66 discovery via genomic shotgun libraries (the Seq-to-SSR approach) has emerged as a 67 reliable and economical methodology for non-model species (Abdelkrim et al. 2009; 68 Allentoft et al., 2009; Castoe et al. 2012a). Several software packages have been 69 developed to identify microsatellite loci this way including MSATCOMMANDER 70 (Faircloth 2008), PALFINDER (Castoe et al. 2012a), and QDD (Meglécz et al. 2010; 71 2014). Typically these methods use de novo assemblies or unassembled reads to 72 identify SSR loci. The use of unassembled reads is a timesaving characteristic (Castoe 73 et al. 2012a; Lance et al. 2013), however, several studies have cautioned against this 74 approach when using short read data, such as from the Illumina platform. These 75 studies have found that Illumina paired-end identified microsatellite loci can have an 76 order of magnitude smaller success rate (in terms of amplification across multiple 77 individuals and sequencing error) than those loci identified from longer 454 or PacBio 78 reads (Drechsler et al. 2013; Wei et al. 2014). Despite this, the use of PALFINDER to 79 identify SSR loci from short, unassembled Illumina reads is widespread (e.g. 80 amphibians, Drechsler et al. 2013; Peterman et al. 2013; bivalves, O’Bryhim et al. 81 2012a; crustaceans, Stoutamore et al. 2012; fish, O’Bryhim et al. 2012b; Nunziata et 82 al. 2013; mammals, Barthelmess et al. 2013; reptiles, Castoe et al. 2012b). 83 Interestingly, few studies have performed validation experiments using SSR loci 84 identified from unassembled reads. Those that have (e.g. Mikheyev et al. 2010; 85 Delmas et al., 2011; Castoe et al. 2012b) have typically used unassembled 454 reads, 86 thus leaving the question of whether SSR loci can be reliably identified from shorter 87 reads poorly addressed outside of a few studies (Drechsler et al. 2013; Wei et al. 88 2014). 89 In this study, we performed validation experiments (via direct sequencing and 90 power analysis) on SSR loci identified with unassembled Illumina data from 91 caecilians (Amphibia, Gymnophiona). Caecilians are limbless amphibians that are 92 restricted mostly to parts of the wet tropics and typically possess a fossorial ecology 93 (Gower & Wilkinson 2008). As such, they are generally rarely encountered and most 94 species are poorly understood (Gower & Wilkinson 2005). Globally, there are ten 4 95 families of caecilian (Wilkinson et al. 2011; Kamei et al. 2012). We focused on 96 Grandisonia alternans (Stejneger,1893), an indotyphlid species that is widely 97 distributed across the Seychelles, an archipelago situated off the coast of east Africa 98 in the Indian Ocean (Fig. 1). With both endemic frog and caecilian radiations the 99 Seychelles is unique among isolated oceanic archipelagos (Nussbaum 1984). Given 100 the exceptional evolutionary insights provided by species occurring on small islands 101 (e.g. Warren et al. 2015), the generally high level of threat of extinction faced by such 102 species (e.g. Daltry 2007), and the scarcity of knowledge of caecilian population 103 genetics (e.g. Gower & Wilkinson 2005), we were motivated to develop population 104 genetics tools for the endemic caecilians of the Seychelles. 105 To accomplish this we identified thousands of putative SSR loci from shotgun 106 genomic sequencing, tested 60 loci to investigate intraspecific utility, generated 107 Sanger sequences to examine sequence similarity to Illumina reads, identified eight 108 loci with putatively desirable characteristics for population genetics and size-scored 109 loci in multiple individuals of G. alternans. We also examined the cross-species 110 utility of these eight loci in additional caecilian taxa and compared divergence in their 111 flanking regions relative to G. alternans sequences. Based on our findings we 112 describe (i) the discovery of six microsatellite loci that amplify across divergent 113 caecilian species, including two loci that satisfy theoretical assumptions of selective 114 neutrally in G. alternans putative populations, and (ii) several important limitations 115 we encountered while using the Seq-to-SSR approach with unassembled Illumina 116 reads. 117 118 Materials and methods 119 120 DNA isolation and microsatellite identification 121 We generated a shotgun genomic library from a pool of six barcoded Seychelles 122 caecilian specimens, comprising representatives of five species: Grandisonia 123 alternans, G. larvata (Ahl 1934), G. sechellensis (Boulenger 1911), Hypogeophis 124 brevis Boulenger 1911 and H. rostratus (Cuvier 1829). Library preparation was 125 performed by first extracting genomic DNA with a Qiagen DNeasy Blood and Tissue 126 kit and then using a standard Illumina Nextera DNA kit to prepare the pooled sample 127 for sequencing (see Lewis et al. 2014). Sequencing was performed using a 500-cycle 128 v.2 reagent kit on an Illumina MiSeq at the Core Research laboratories of the Natural 5 129 History Museum, London. We removed and trimmed low quality reads of 130 unassembled paired-end data using Illumina software and the FASTX-Toolkit 131 (available at http://hannonlab.cshl.edu/fastx_toolkit/links.html). Barcoded pooled data 132 were de-multiplexed and only sequences from the target taxa G. alternans were 133 retained, originating from a single G. alternans individual from Silhouette Island 134 (UMMZ 192945). This single individual dataset was used in all downstream analysis. 135 136 Potentially amplifiable loci (PAL) selection 137 We used PALFINDER software v 2.03 (Castoe et al. 2012a) to identify putative SSR 138 loci from NGS output, run with default settings and applying the following criteria in 139 Primer3 (Untergasser et al. 2012): (i) a minimum of eight tandem repeats for 140 dinucleotide motifs, (ii) a minimum of six tandem repeats for trinucleotide motifs, and 141 (iii) a minimum of six tandem repeats for tetranucleotide motifs. From the 142 PALFINDER/Primer3
Load more

Recommended publications
  • The Caecilians of the World: a Taxonomic Review by Edward Harrison Taylor Review By: Marvalee H
    The Caecilians of the World: A Taxonomic Review by Edward Harrison Taylor Review by: Marvalee H. Wake Copeia, Vol. 1969, No. 1 (Mar. 6, 1969), pp. 216-219 Published by: American Society of Ichthyologists and Herpetologists (ASIH) Stable URL: http://www.jstor.org/stable/1441738 . Accessed: 25/03/2014 11:09 Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at . http://www.jstor.org/page/info/about/policies/terms.jsp . JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected]. American Society of Ichthyologists and Herpetologists (ASIH) is collaborating with JSTOR to digitize, preserve and extend access to Copeia. http://www.jstor.org This content downloaded from 192.188.55.3 on Tue, 25 Mar 2014 11:09:44 AM All use subject to JSTOR Terms and Conditions 216 COPEIA, 1969, NO. 1 three year period, some of the latter per- add-not only the Indo-Pacific, but this Indo- sonally by Munro. The book must be used Australian archipelago, the richest area in in conjunction with the checklist "The the world for marine fish species, badly needs Fishes of the New Guinea Region" (Papua more work of this high calibre.-F. H. TAL- and New Guinea Agr. J. 10:97-339, 1958), BOT, Australian Museum, 6-8 College Street, a sizable work in itself, including a full list Sydney, Australia.
    [Show full text]
  • Biogeographic Analysis Reveals Ancient Continental Vicariance and Recent Oceanic Dispersal in Amphibians ∗ R
    Syst. Biol. 63(5):779–797, 2014 © The Author(s) 2014. Published by Oxford University Press, on behalf of the Society of Systematic Biologists. All rights reserved. For Permissions, please email: [email protected] DOI:10.1093/sysbio/syu042 Advance Access publication June 19, 2014 Biogeographic Analysis Reveals Ancient Continental Vicariance and Recent Oceanic Dispersal in Amphibians ∗ R. ALEXANDER PYRON Department of Biological Sciences, The George Washington University, 2023 G Street NW, Washington, DC 20052, USA; ∗ Correspondence to be sent to: Department of Biological Sciences, The George Washington University, 2023 G Street NW, Washington, DC 20052, USA; E-mail: [email protected]. Received 13 February 2014; reviews returned 17 April 2014; accepted 13 June 2014 Downloaded from Associate Editor: Adrian Paterson Abstract.—Amphibia comprises over 7000 extant species distributed in almost every ecosystem on every continent except Antarctica. Most species also show high specificity for particular habitats, biomes, or climatic niches, seemingly rendering long-distance dispersal unlikely. Indeed, many lineages still seem to show the signature of their Pangaean origin, approximately 300 Ma later. To date, no study has attempted a large-scale historical-biogeographic analysis of the group to understand the distribution of extant lineages. Here, I use an updated chronogram containing 3309 species (~45% of http://sysbio.oxfordjournals.org/ extant diversity) to reconstruct their movement between 12 global ecoregions. I find that Pangaean origin and subsequent Laurasian and Gondwanan fragmentation explain a large proportion of patterns in the distribution of extant species. However, dispersal during the Cenozoic, likely across land bridges or short distances across oceans, has also exerted a strong influence.
    [Show full text]
  • Biodiversity in Sub-Saharan Africa and Its Islands Conservation, Management and Sustainable Use
    Biodiversity in Sub-Saharan Africa and its Islands Conservation, Management and Sustainable Use Occasional Papers of the IUCN Species Survival Commission No. 6 IUCN - The World Conservation Union IUCN Species Survival Commission Role of the SSC The Species Survival Commission (SSC) is IUCN's primary source of the 4. To provide advice, information, and expertise to the Secretariat of the scientific and technical information required for the maintenance of biologi- Convention on International Trade in Endangered Species of Wild Fauna cal diversity through the conservation of endangered and vulnerable species and Flora (CITES) and other international agreements affecting conser- of fauna and flora, whilst recommending and promoting measures for their vation of species or biological diversity. conservation, and for the management of other species of conservation con- cern. Its objective is to mobilize action to prevent the extinction of species, 5. To carry out specific tasks on behalf of the Union, including: sub-species and discrete populations of fauna and flora, thereby not only maintaining biological diversity but improving the status of endangered and • coordination of a programme of activities for the conservation of bio- vulnerable species. logical diversity within the framework of the IUCN Conservation Programme. Objectives of the SSC • promotion of the maintenance of biological diversity by monitoring 1. To participate in the further development, promotion and implementation the status of species and populations of conservation concern. of the World Conservation Strategy; to advise on the development of IUCN's Conservation Programme; to support the implementation of the • development and review of conservation action plans and priorities Programme' and to assist in the development, screening, and monitoring for species and their populations.
    [Show full text]
  • 3Systematics and Diversity of Extant Amphibians
    Systematics and Diversity of 3 Extant Amphibians he three extant lissamphibian lineages (hereafter amples of classic systematics papers. We present widely referred to by the more common term amphibians) used common names of groups in addition to scientifi c Tare descendants of a common ancestor that lived names, noting also that herpetologists colloquially refer during (or soon after) the Late Carboniferous. Since the to most clades by their scientifi c name (e.g., ranids, am- three lineages diverged, each has evolved unique fea- bystomatids, typhlonectids). tures that defi ne the group; however, salamanders, frogs, A total of 7,303 species of amphibians are recognized and caecelians also share many traits that are evidence and new species—primarily tropical frogs and salaman- of their common ancestry. Two of the most defi nitive of ders—continue to be described. Frogs are far more di- these traits are: verse than salamanders and caecelians combined; more than 6,400 (~88%) of extant amphibian species are frogs, 1. Nearly all amphibians have complex life histories. almost 25% of which have been described in the past Most species undergo metamorphosis from an 15 years. Salamanders comprise more than 660 species, aquatic larva to a terrestrial adult, and even spe- and there are 200 species of caecilians. Amphibian diver- cies that lay terrestrial eggs require moist nest sity is not evenly distributed within families. For example, sites to prevent desiccation. Thus, regardless of more than 65% of extant salamanders are in the family the habitat of the adult, all species of amphibians Plethodontidae, and more than 50% of all frogs are in just are fundamentally tied to water.
    [Show full text]
  • Quantitative Surveying of Endogeic Limbless Vertebrates— a Case Study of Gegeneophis Ramaswamii (Amphibia: Gymnophiona: Caeciliidae) in Southern India G.J
    Applied Soil Ecology 23 (2003) 43–53 Quantitative surveying of endogeic limbless vertebrates— a case study of Gegeneophis ramaswamii (Amphibia: Gymnophiona: Caeciliidae) in southern India G.J. Measey a,∗, D.J. Gower a, O.V. Oommen b, M. Wilkinson a a Department of Zoology, The Natural History Museum, London SW7 5BD, UK b Department of Zoology, University of Kerala, Kariavattom, Thiruvananthapuram, India Received 10 September 2002; received in revised form 16 December 2002; accepted 17 December 2002 Abstract Many subterranean, limbless reptiles and amphibians are predators of invertebrate soil ecosystem engineers. The potential importance of these predators in soil ecology partly rests on whether they occur in high densities, but their abundance has rarely been measured, and there are no standard methods. The mostly tropical and fossorial caecilians (Amphibia: Gymnophiona) are often considered rare, but there are very few quantitative data, and some species, including Gegeneophis ramaswamii,have been reported as abundant in some situations. Using simple and repeatable survey methods with randomised 1 m2 quadrats, surveys of G. ramaswamii were conducted at five localities in southern India. Densities of 0–1.87 m−2 per survey were measured, with means of 0.51 and 0.63 m−2 at the beginning and middle of monsoon, respectively. These densities were far greater than for sympatric caecilians (ichthyophiids; uraeotyphlids) and fossorial snakes (typhlopids; colubrids). While ecological data remain very scant, establishing quantitative methods to assess the abundance of endogeic limbless vertebrates is an important step toward greater understanding of subterranean predator–prey relations, and of monitoring populations of these poorly known organisms.
    [Show full text]
  • Grandisonia Sechellensis
    Grandisonia sechellensis https://sis.iucnsis.org/apps/org.iucn.sis.server.extensions.reports/reports... Draft Grandisonia sechellensis - (Boulenger, 1909) ANIMALIA - CHORDATA - AMPHIBIA - GYMNOPHIONA - CAECILIIDAE - Grandisonia - sechellensis Common Names: No Common Names Synonyms: No Synonyms Red List Status LC - Least Concern, (IUCN version 3.1) Red List Assessment Assessment Information Date of Assessment: 2012-10-31 Assessor(s): IUCN SSC Amphibian Specialist Group, Contributor(s): Gerlach, J. & Nussbaum, R. Facilitators/Compilers: Luedtke, J. Regions: Global Assessment Rationale Listed as Least Concern despite a small estimated Extent of Occurrence of 217 km2, because it is generally common, adaptable, and does not appear to be in decline. Reasons for Change No change: Same category and criteria Distribution Geographic Range This species occurs on three islands in the Seychelles: Mahé, Praslin and Silhouette. Using its range as a proxy, its Extent of Occurrence has been estimated at 217 km2. Extent of Occurrence (EOO) Estimated extent of occurrence (EOO)- in km2: 217 Map Status Map Status Data Sensitive? Justification Geographic range this applies to: Date restriction imposed: Done - - - - Biogeographic Realms Biogeographic Realm: Afrotropical Occurrence Countries of Occurrence 1 of 3 02/11/2012 14:48 Grandisonia sechellensis https://sis.iucnsis.org/apps/org.iucn.sis.server.extensions.reports/reports... Country Presence Origin Formerly Bred Seasonality Seychelles Extant Native - Resident Population It is common in both anthropogenically modified and undisturbed habitats. Population Information Current Population Trend: Unknown Severely fragmented? Justification Unknown - Habitats and Ecology While it lives in undisturbed rainforest in the hills of the islands, it also tolerates a degree of habitat disturbance. It has been found on the coastal plateaux at disturbed sites with plantations and buildings, and along streams in degraded forest at higher elevations.
    [Show full text]
  • Reproduction and Larval Rearing of Amphibians
    Reproduction and Larval Rearing of Amphibians Robert K. Browne and Kevin Zippel Abstract Key Words: amphibian; conservation; hormones; in vitro; larvae; ovulation; reproduction technology; sperm Reproduction technologies for amphibians are increasingly used for the in vitro treatment of ovulation, spermiation, oocytes, eggs, sperm, and larvae. Recent advances in these Introduction reproduction technologies have been driven by (1) difficul- ties with achieving reliable reproduction of threatened spe- “Reproductive success for amphibians requires sper- cies in captive breeding programs, (2) the need for the miation, ovulation, oviposition, fertilization, embryonic efficient reproduction of laboratory model species, and (3) development, and metamorphosis are accomplished” the cost of maintaining increasing numbers of amphibian (Whitaker 2001, p. 285). gene lines for both research and conservation. Many am- phibians are particularly well suited to the use of reproduc- mphibians play roles as keystone species in their tion technologies due to external fertilization and environments; model systems for molecular, devel- development. However, due to limitations in our knowledge Aopmental, and evolutionary biology; and environ- of reproductive mechanisms, it is still necessary to repro- mental sensors of the manifold habitats where they reside. duce many species in captivity by the simulation of natural The worldwide decline in amphibian numbers and the in- reproductive cues. Recent advances in reproduction tech- crease in threatened species have generated demand for the nologies for amphibians include improved hormonal induc- development of a suite of reproduction technologies for tion of oocytes and sperm, storage of sperm and oocytes, these animals (Holt et al. 2003). The reproduction of am- artificial fertilization, and high-density rearing of larvae to phibians in captivity is often unsuccessful, mainly due to metamorphosis.
    [Show full text]
  • Comparative Morphology of Caecilian Sperm (Amphibia: Gymnophiona)
    JOURNAL OF MORPHOLOGY 221:261-276 (1994) Com parative Morphology of Caecilian Sperm (Amp h i bi a: Gym nop h ion a) MAFWALEE H. WAKE Department of Integrative Biology and Museum of Vertebrate Zoology, University of California, Berkeley, California 94720 ABSTRACT The morphology of mature sperm from the testes of 22 genera and 29 species representing all five families of caecilians (Amphibia: Gymnoph- iona) was examined at the light microscope level in order to: (1)determine the effectiveness of silver-staining techniques on long-preserved, rare material, (2) assess the comparative morphology of sperm quantitatively, (3) compare pat- terns of caecilian sperm morphology with that of other amphibians, and (4) determine if sperm morphology presents any characters useful for systematic analysis. Although patterns of sperm morphology are quite consistent intrage- nerically and intrafamilially, there are inconsistencies as well. Two major types of sperm occur among caecilians: those with very long heads and pointed acrosomes, and those with shorter, wider heads and blunt acrosomes. Several taxa have sperm with undulating membranes on the flagella, but limitations of the technique likely prevented full determination of tail morphology among all taxa. Cluster analysis is more appropriate for these data than is phylogenetic analysis. cc: 1994 Wiley-Liss, Inc. Examination of sperm for purposes of describ- ('70), in a general discussion of aspects of ing comparative sperm morphology within sperm morphology, and especially Fouquette and across lineages
    [Show full text]
  • Amphibia: Gymnophiona)
    Molecular Phylogenetics and Evolution 53 (2009) 479–491 Contents lists available at ScienceDirect Molecular Phylogenetics and Evolution journal homepage: www.elsevier.com/locate/ympev A mitogenomic perspective on the phylogeny and biogeography of living caecilians (Amphibia: Gymnophiona) Peng Zhang a,b,*, Marvalee H. Wake a,* a Department of Integrative Biology and Museum of Vertebrate Zoology, 3101 Valley Life Sciences Building, University of California, Berkeley, CA 94720-3160, USA b Key Laboratory of Gene Engineering of the Ministry of Education, Sun Yat-sen University, Guangzhou 510275, PR China article info abstract Article history: The caecilians, members of the amphibian Order Gymnophiona, are the least known Order of tetrapods, Received 6 February 2009 and their intra-relationships, especially within its largest group, the Family Caeciliidae (57% of all caeci- Revised 15 June 2009 lian species), remain controversial. We sequenced thirteen complete caecilian mitochondrial genomes, Accepted 30 June 2009 including twelve species of caeciliids, using a universal primer set strategy. These new sequences, Available online 3 July 2009 together with eight published caecilian mitochondrial genomes, were analyzed by maximum parsimony, partitioned maximum-likelihood and partitioned Bayesian approaches at both nucleotide and amino acid Keywords: levels, to study the intra-relationships of caecilians. An additional multiple gene dataset including most of Caeciliidae the caecilian nucleotide sequences currently available in GenBank produced phylogenetic results that are Amphibian Mitochondrial genome fully compatible with those based on the mitogenomic data. Our phylogenetic results are summarized as Molecular dating follow. The caecilian family Rhinatrematidae is the sister taxon to all other caecilians. Beyond Rhinatre- matidae, a clade comprising the Ichthyophlidae and Uraeotyphlidae is separated from a clade containing all remaining caecilians (Scolecomorphidae, Typhlonectidae and Caeciliidae).
    [Show full text]
  • Embryonic and Larval Development in the Caecilian Ichthyophis Kohtaoensis (Amphibia, Gymnophiona): a Staging Table
    JOURNAL OF MORPHOLOGY 243:3–34 (2000) Embryonic and Larval Development in the Caecilian Ichthyophis kohtaoensis (Amphibia, Gymnophiona): A Staging Table Nicole Du¨ nker,1 Marvalee H. Wake,2* and Wendy M. Olson2 1 Department of Zoology, Technical University of Darmstadt, Darmstadt, Germany 2 Department of Integrative Biology and Museum of Vertebrate Zoology, University of California, Berkeley, California ABSTRACT Little is known about the developmental of the lateral line organs, formation of three pairs of ex- biology of caecilians—tropical, elongate, limbless, mostly ternal gills, development of the eyes, changes in yolk fossorial amphibians that are members of the Order Gym- structure, changes in the structure of the cloacal aperture nophiona. Ichthyophis kohtaoensis (Family Ichthyophi- and growth of the tail, including the formation and regres- idae; southeast Asia) is an oviparous species in which sion of the tail fin. This study provides a comparison with maternal care of the clutch is provided. The clutch is laid descriptions of embryonic stages of I. glutinosus and Hy- in a burrow on land, and the embryos develop in their egg pogeophis rostratus and with a recent staging table for the membranes, curved around a large yolk mass. Larvae are aquatic, viviparous caecilian Typhlonectes compressi- aquatic and exhibit characteristic features that are not cauda, the only other caecilians for which reasonably com- present in the terrestrial adults. Because accurate de- plete ontogenetic information exists in the literature. scriptions of ontogenies and the establishment of stan- Comparisons with established staging tables for selected dardized stages of embryonic and larval development are useful for both experimental and comparative embryology, frogs and salamanders are also presented.
    [Show full text]
  • Development of the Skull of Dermophis Mexicanus (Amphibia: Gymnophiona), with Comments on Skull Kinesis and Amphibian Relationships
    JOURNAL OF MORPHOLOGY 173:203-223 (1982) Development of the Skull of Dermophis mexicanus (Amphibia: Gymnophiona), With Comments on Skull Kinesis and Amphibian Relationships MARVALEE H. WAKE AND JAMES HANKEN Department of Zoology and Museum of Vertebrate Zoology, University of California, Berkeley, California 94720 ABSTRACT The development of the skull of Dermophis mexicanus (Caeciliidae)is described and compared to that of other caecilians. The chondrocra- nium is well developed in embryos of 25 mm total length (TL);ossification begins in the quadrate and the articular element of the lower jaw at about 30 mm TL. The occipital arch then ossifies, followed by the dorsal and lateral dermal bones, then the ventral endochondral and dermal elements. The stapes ossifies at 55 mm TL. The amount of skull roofing increases during ontogeny, although the anterior rims of the nasal capsules, the anterior part of the mesethmoid, and the hyoid appara- tus remain cartilaginous throughout life. Dermophis mexicanus lacks many pri- mary embryonic ossification centers reported by Marcus et al. (’35)for Hypogeo- phis;presence of these ossification centers has been presumed to be indicative of a primitive skull morphology derived with little modification from archaic amphib- ians (“stegocephalians”).The fetal skull is highly kinetic, and some kinesis is re- tained in adults. We suggest that fetal skull kinesis and early ossification of jaw suspension elements are functionally related to the intraoviducal feeding mode of this viviparous species. Based on this evidence, together with the observed ossifi- cation pattern and bone homologies, we conclude that stegokrotaphy (complete skull roofing) in caecilians is a derived condition, correIated with fossoriality, and does not indicate a direct relationship of caecilians to any known early amphibian taxon.
    [Show full text]
  • The Palaeozoic Ancestry of Salamanders, Frogs and Caecilians
    Blackwell Publishing LtdOxford, UKZOJZoological Journal of the Linnean Society0024-4082The Lin- nean Society of London, 2007? 2007 150s2 1140 Original Articles LISSAMPHIBIAN ANCESTRYR. L. CARROLL Zoological Journal of the Linnean Society, 2007, 150 (Suppl. 1), 1–140. With 78 figures The Palaeozoic Ancestry of Salamanders, Frogs and Caecilians ROBERT L. CARROLL FLS1 1Redpath Museum, McGill University, 859 Sherbrooke St W., Montreal, P.Q. Canada, H3A 2K6 The relationships of frogs, salamanders, and caecilians (Gymnophiona) with one another and with the vast assem- blage of Palaeozoic amphibians remain highly contentious phylogenetic problems. Cladistic analyses support a com- mon ancestry of the three modern orders, but fail to achieve a consensus regarding their affinities with Palaeozoic amphibians. The most exhaustive phylogenetic analyses that have been applied to the ancestry of lissamphibians have recognized few, if any, biologically significant characters differentiating the living orders. These results can be attributed to limiting the database primarily to characters common to Palaeozoic amphibians and including few fea- tures that distinguish the modern orders. Making use of the numerous derived characters that are expressed in either the larvae or adults of extant salamanders, frogs, and caecilians provides the basis for recognizing a nested sequence of synapomorphies that support a common ancestry of salamanders and anurans with temnospondyl lab- yrinthodonts to the exclusion of caecilians. The larvae of Carboniferous and Permian temnospondyl labyrinthodonts provide strong evidence for their being members of the stem group of urodeles. This is based primarily on the great similarity in the sequence of ossification of the bones of the skull and appendicular skeleton, but is also supported by detailed similarities of the hyoid apparatus.
    [Show full text]