Research Methods in Life Sciences Commons^™

The Tadpole Of Pseudis Minuta (Anura: Pseudidae), An Apparent Case Of Heterochrony, Rafael O. De Sá, Esteban O. Lavilla

Biology Faculty Publications

The external morphology, oral disc, and coloration pattern of the larva of Pseudis minuta are described. Tadpoles are mostly bottom dwellers that have a small, terminal oral disc with a labial tooth row formula 1(1-1)/(1-1)2. Internal oral anatomy is characterized using scanning electron microscopy, representing the only description available for the family Pseudidae. The coloration pattern of P. minuta tadpoles is compared with that of other pseudids. Pseudis minuta larvae do not exhibit the ontogenetic coloration change reported for P. paradoxa. Considering larval coloration, larval size, and reports of adult size, acceleration or hypermorphosis are suggested as possible heterochronic mechanisms …

External Morphology Of The Chorion Of The Annual Fishes Cynolebias (Cyprinodontiformes: Rivulidae), Marcelo Loureiro, Rafael O. De Sá

Biology Faculty Publications

Members of the family Rivulidae (killifishes) inhabit temporary bodies of freshwater in South and Central America (one species is also found in North America). The most remarkable characteristic of the family Rivulidae is that species have an annual life cycle with a drought-resistant egg during the dry season. Parenti's (1981) analysis of the order Cyprinodontiformes considered a single genus, Cynolebias, whereas Cos- ta's (1990) phylogenetic analysis of the family Rivulidae separates Cynolebias from Cynopoecilus. One of Costa's synapomorphies to separate Cynopoecilus is the unique structure of their egg's chorion, which is shared with Leptolebias and Campellolebias.

Xenopus Laevis As A Model Organism, David C. Cannatella, Rafael O. De Sá

Biology Faculty Publications

Model organisms are often assumed to be representative of some more inclusive taxon of which the species is a part. This assumption leads to mistaken generalizations about the evolutionary and comparative significance of the data gathered. This paper reviews com? parative and evolutionary studies of Xenopus laevis and its relatives. Phylogenetic analysis of data from DNA sequences and morphology indicate that Xenopus is monophyletic and that Silurana is its sister group. The most basal lineages of Pipidae diverged prior to the breakup of Gondwana. The bizarre morphology of Xenopus is in part due to changes in the mode of meta? …

Ribosomal Dna And The Phylogeny Of Frogs, David M. Hills, Loren K. Ammerman, Michael T. Dixon, Rafael O. De Sá

Biology Faculty Publications

Phylogenetic analysis of 1656 aligned sites in the 28S ribosomal RNA gene of frogs supports some of the recently recognized higher groups of anurans but provides counter-support for others. The 28S rDNA data support the monophyly of the recently recognized Pipanura (me- sobatrachians plus neobatrachians), which in turn indicates paraphyly of archaeobatrachians. Me- sobatrachians (pelobatoids plus pipoids), which are either considered paraphyletic or weakly sup- ported as monophyletic in morphological analyses, also receive support as a monophyletic group from the 28S rDNA data. Hyloidea (=Bufonoidea), which is widely recognized but lacks morphological support, receives some molecular support as being monophyletic. …

Life History, Ecology, And Morphology Of The Ravine Salamander, Plethodon Richmondi, Ronnie D. Jewell

Theses, Dissertations and Capstones

The distribution of P. richmondi and P. cinereus has been of interest to herpetologist for many years. Plethodon cinereus is found throughout the state except for part of the Allegheny Plateau Province where P. richmondi occurs. There is a somewhat abrupt end to their ranges where they overlap which does not appear to be influenced by elevational differences, vegetation patterns, or general climatic changes. The propose of this study was to determine if temperature and/or moisture are limiting the distribution of P. richmondi and P. cinereus in West Virginia. The natural history of P. richmondi has not in West Virginia …

The Ecology Of Maine's Intertidal Habitats : A Report Prepared For The Maine State Planning Office, Peter F. Larsen, Lee F. Doggett

Maine Collection

The Ecology of Maine's Intertidal Habitats : A Report Prepared for the Maine State Planning Office

by Bigelow Laboratory for Ocean Sciences (Authors: Peter F. Larsen and Lee F. Doggett) , 1981.

Contents: Acknowledgements / List of Tables / List of Figures / Chapter 1 - Introduction / Chapter 2 - Human Impact on Intertidal Fauna / Chapter 3 - A Primer of Intertidal Ecology / Chapter 4 - A Sampler of Intertidal Species / Chapter 5 - Methodology / Chapter 6 - Results of Faunal Studies / Appendix 1 - Habitats With Date Sampled / Appendix 2 - List …

Sub-Aversive Response Contingent Foot Shock As A Positive Reinforcer, Robert Lea Fulwiler

All Master's Theses

Forty-eight rats were divided into 8 groups; four were maintained under normal conditions and the other four under sensory deprivation and tested at o, 3, 6, and 9 days after condition institution. The response was placing the head through a hole in the operant chamber and the stimulus (0, 1.2, 4, or 12 Vac) was contingent upon the response. Analysis ot variance disclosed significant differences (p<.01) between the deprived and the non-deprived groups at days 6 and 9; and a significant interaction between deprivation condition and time of test. No differences were shown between the stimulus intensities indicating that the stimulus did not have a reinforcing effect.