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Articles 1 - 13 of 13
Full-Text Articles in Animal Sciences
A Re-Assessment Of Priority Amphibian Species Of Peru, Edgar Lehr, Laurence Jarvis, Ariadne Angulo, Alessandro Catenazzi, Rudolf Von May, Jason Brown, James Lewis
A Re-Assessment Of Priority Amphibian Species Of Peru, Edgar Lehr, Laurence Jarvis, Ariadne Angulo, Alessandro Catenazzi, Rudolf Von May, Jason Brown, James Lewis
Edgar Lehr
Peru supports approximately 588 amphibian species, of which 492 have been assessed on the IUCN Red List of Threatened Species. Of these, 111 are classified as Threatened, with 69 species classified as Critically Endangered or Endangered. In addition, 140 amphibian species remain Data Deficient. We re-assessed the conservation status of 38 amphibian species originally identified as potentially Threatened by von May et al. (2008), using the IUCN Red List Categories and Criteria. Fourteen species assessments changed as a result of re-assessment, of which eight changed from Data Deficient to Threatened; two changed from Data Deficient to Near Threatened and Least …
Reduction Of Water Surface Tension Significantly Impacts Gecko Adhesion Underwater, Peter Niewiarowski, Ali Dhinojwala, Alyssa Stark, Brandon Mcclung
Reduction Of Water Surface Tension Significantly Impacts Gecko Adhesion Underwater, Peter Niewiarowski, Ali Dhinojwala, Alyssa Stark, Brandon Mcclung
Dr. Peter H. Niewiarowski
The gecko adhesive system is dependent on weak van der Waals interactions that are multiplied across thousands of fine hair-like structures (setae) on geckos' toe pads. Due to the requirements of van der Waals forces, we expect that any interruption between the setae and substrate, such as a water layer, will compromise adhesion. Our recent results suggest, however, that the air layer (plastron) surrounding the superhydrophobic toe pads aid in expelling water at the contact interface and create strong shear adhesion in water when in contact with hydrophobic surfaces. To test the function of the air plastron, we reduced the …
The Larvae Of Eurycea Junaluska (Amphibia: Caudata: Plethodontidae), With Comments On Distribution, Travis Ryan
The Larvae Of Eurycea Junaluska (Amphibia: Caudata: Plethodontidae), With Comments On Distribution, Travis Ryan
Travis J. Ryan
Travis J. Ryan's shorter contribution to Copeia 1997.
Ultrastructure Of The Reproductive System Of The Black Swamp Snake (Seminatrix Pygaea): Part Ii. Annual Oviducal Cycle, David Sever, Travis Ryan, Deborah Patton, Shannon Swafford
Ultrastructure Of The Reproductive System Of The Black Swamp Snake (Seminatrix Pygaea): Part Ii. Annual Oviducal Cycle, David Sever, Travis Ryan, Deborah Patton, Shannon Swafford
Travis J. Ryan
This article is the first ultrastructural study on the annual oviducal cycle in a snake. The ultrastructure of the oviduct was studied in 21 females of the viviparous natricine snake Seminatrix pygaea. Specimens were collected and sacrificed in March, May, June, July, and October from one locale in South Carolina during 1998–1999. The sample included individuals: 1) in an inactive reproductive condition, 2) mated but prior to ovulation, and 3) from early and late periods of gravidity. The oviduct possesses four distinct regions from cranial to caudal: the anterior infundibulum, the posterior infundibulum containing sperm storage tubules (SSTs), the uterus, …
Does Sex Influence Post-Reproductive Metamorphosis In Ambystoma Talpoideum?, Travis Ryan, Gabrielle Swenson
Does Sex Influence Post-Reproductive Metamorphosis In Ambystoma Talpoideum?, Travis Ryan, Gabrielle Swenson
Travis J. Ryan
Shorter communication in the Journal of Herpetology v. 35.
Eurycea Junaluska. Morphology, Travis Ryan
Eurycea Junaluska. Morphology, Travis Ryan
Travis J. Ryan
Morphology of Junaluska salamander.
Growth And The Expression Of Alternative Life Cycles In The Salamander Ambystoma Talpoideum (Caudata: Ambystomatidae), Travis Ryan, Raymond Semlitsch
Growth And The Expression Of Alternative Life Cycles In The Salamander Ambystoma Talpoideum (Caudata: Ambystomatidae), Travis Ryan, Raymond Semlitsch
Travis J. Ryan
Complex life cycles (CLCs) contain larval and adult phases that are morphologically and ecologically distinct. Simple life cycles (SLCs) have evolved from CLCs repeatedly in a wide variety of lineages but the processes that may underlie the transition have rarely been identified or investigated experimentally. We examined the influence of larval growth rate on the facultative expression of alternative life cycles (metamorphosis or maturation as gill-bearing adults [= paedomorphosis]) in the salamander Ambystoma talpoideum. We manipulated growth rates by altering the amount of food individuals received throughout larval development. The expression of alternative life cycles in A. talpoideum is influenced …
Evaporative Water Loss In Two Natricine Snakes, Nerodia Fasciata And Seminatrix Pygaea, Christopher Winne, Travis Ryan, Yale Leiden, Michael Dorcas
Evaporative Water Loss In Two Natricine Snakes, Nerodia Fasciata And Seminatrix Pygaea, Christopher Winne, Travis Ryan, Yale Leiden, Michael Dorcas
Travis J. Ryan
Shorter communication in Journal of Herpetology v. 35.
Aspects Of Sex-Specific Differences In The Expression Of An Alternative Life Cycle In The Salamander Ambystoma Talpoideum, Christopher Winne, Travis Ryan
Aspects Of Sex-Specific Differences In The Expression Of An Alternative Life Cycle In The Salamander Ambystoma Talpoideum, Christopher Winne, Travis Ryan
Travis J. Ryan
A recent evolutionary ecological model of facultative paedomorphosis predicts that body size of mature individuals should be larger than immatures of the same cohort. We investigated sex-specific differences in body size and maturation within a single cohort of branchiate (= larval and paedomorphic) mole salamanders, Ambystoma talpoideum. In addition, we also sampled the population after the breeding season, as some individuals began to undergo metamorphosis and leave the pond. The branchiate population was female-biased (62.7%), and mature (paedomorphic) females were significantly smaller than paedomorphic males or immature (larval) females. The majority of male branchiates were mature (86.6%), whereas significantly fewer …
Life History Evolution And Adaptive Radiation Of Hemidactyliine Salamanders, Travis Ryan, R. Bruce
Life History Evolution And Adaptive Radiation Of Hemidactyliine Salamanders, Travis Ryan, R. Bruce
Travis J. Ryan
T.J. Ryan and R.C. Bruce's contribution to: The Biology of Plethodontid Salamanders, R. C. Bruce, R. G. Jaeger, and L. D. Houck, eds. Kluwer Academic/Plenum Publishers, New York.
Ultrastructure Of The Reproductive System Of The Black Swamp Snake (Seminatrix Pygaea). I. Evidence For Oviducal Sperm Storage, David Sever, Travis Ryan
Ultrastructure Of The Reproductive System Of The Black Swamp Snake (Seminatrix Pygaea). I. Evidence For Oviducal Sperm Storage, David Sever, Travis Ryan
Travis J. Ryan
Oviducal sperm storage in the viviparous (lecithotrophic) colubrid snake Seminatrix pygaea was studied by light and electron microscopy. Out of 17 adult snakes examined from May–October, sperm were found in the oviducts of only two specimens. In a preovulatory female sacrificed 14 May, sperm were found in the oviducal lumen and sperm storage tubules (SSTs) of the posterior infundibulum. In a nonvitellogenic female sacrificed 9 June, sperm were found in the lumen and glands of the posterior uterus and anterior vagina, indicating a recent mating. The glands in the posterior infundibulum and vagina were simple or compound tubular, whereas glands …
Larval Life History And Abundance Of A Rare Salamander, Eurycea Junaluska (Plethodontidae), Travis Ryan
Larval Life History And Abundance Of A Rare Salamander, Eurycea Junaluska (Plethodontidae), Travis Ryan
Travis J. Ryan
The larval life history of Eurycea junaluska was studied in three southwestern North Carolina populations. Populations were sampled quarterly over a 13 mo period and size-class analyses were used to evaluate the pattern of larval growth and metamorphosis. Young of the year appeared in the late spring and experienced rapid growth through the first summer. Growth slowed in the second year and metamorphosis usually occured in the summer at about 25.5 mo post-hatching, although some data suggest that either 1yr or 3yr larval periods may be possible. The overall larval growth rate of E. junaluska is estimated at 1.27 mm/mo, …
Biomass Turnover, Energy Balance, And Interpopulation Variation In The Stream Limpet, Ferrissia Rivularis (Say), With Special Reference To Respiration, Growth, And Fecundity, Albert Burky
Albert J. Burky
This investigation extends from 1965 through 1968 and involves 42,926 individual measurements on 19,479 limpets from populations of F. rivularis in the Canandaigua Outlet at Alloway, New York (AL)* and in Black Creek at Cleveland, New York (BC)*, with some comparative results from a population in Chittenango Creek at Cazenovia, New York (CC)*. These localities are located in the Seneca-Clyde-Oneida drainage system which flows by way of the Oswego River into Lake Ontario. For populations at AL (eutrophic environment) and BC (mesotrophic environment) variations in life-cycle, accompanied by marked differences in fecundity and biomass turnover rates (growth and egg reproduction), …