Tadpoles Research Articles

Determination method of co-orbital objects in the solar system

ABSTRACT In this paper, based on two-dimensional maps from the semi-analytical Hamiltonian approach, we proposed an improved determination method to classify co-orbital objects in the solar system without numerical integration. Taking advantage of a simple pattern analysis, we present two certainty conditions to recognize co-orbital objects with uncertain orbital parameters. Then, our determination method is applied to classify potential co-orbital objects (PCOs) of Mars, Jupiter, Saturn, Uranus, and Neptune, and then their results are verified through numerical integration in the multiplanet model, respectively. Through our method, we identify 11 new co-orbital objects for the first time, including four Mars trojans i.e. tadpole (TP) objects, one short-term Mars quasi-satellite (QS), one Mars horseshoe (HS), one Jupiter QS, one short-term Uranus trojan, one Uranus PCO, and one Neptune PCO with short-term transitions between QS and HS, and one Neptune PCO with short-term transition between QS and TP. Numerical computation shows that except Saturn PCOs significantly perturbed by Jupiter, our determination method for co-orbital objects in the solar system is effective, but it cannot deal with the classification of PCOs near the boundary of different co-orbital regions. Since our method does not rely on time-consuming numerical integration, it is efficient and suitable for a large amount of screening for numerous co-orbital objects in the solar system.

Stability Analysis of Earth Co-orbital Objects

In this paper, we investigate the stability of Earth co-orbital objects (ECOs) based on the torus structure. The Hamiltonian value is an index to evaluate co-orbital stability. According to topological characters of tadpole (TP), horseshoe (HS), quasi-satellite (QS), and critical compound surfaces in the torus space, the co-orbital area is divided into several regions in detail. We select 221 potential ECOs as representative samples. Numerical integration in the Sun–Earth system illustrates that most of objects above the collision line are short- or long-term stable ECOs in the QS–HS and QS–TP motions, and most of objects in the unstable region are unstable ones, which is in agreement with our semi-analytical conclusions. The stability of an ECO with a larger Hamiltonian value could be stronger. An efficient method to determine the long-term co-orbital stability of a potential ECO is proposed without long-term numerical integration. Numerical integration in the multiplanet model demonstrates that our stability analysis is still applicable for the real solar system. As an application of our stability analysis, two well-determined QS–HS ECOs above the collision line are identified and analyzed for the first time. For instance, the QS–HS state of 2019 VL5 can be sustained for more than 3000 yr, and its current HS state will be sustained for at least 800 yr.

Adaptive significance of the transparent body in the tadpoles of ornamented pygmy frog, Microhyla ornata (Anura, Amphibia)

In Southern India, during the Southwest monsoon phase, the newly formed ephemeral water bodies harbour several species of tadpoles as well as some of their predators. Tadpoles of Microhyla ornata dwell in surface or column zones of water. They face predation threat from aquatic insect predators and carnivorous tadpoles of other anurans though they are invisible due to their transparent body form. We tested whether transparent body form of M. ornata tadpoles is a useful attribute against predation by exposing tail fin stained (with the Nile blue) subjects to a naturally occurring predator (Hoplobatrachus tigerinus tadpoles that detect prey using both visual and chemical cues). The study shows that susceptibility of stained M. ornata tadpoles to predation increased significantly compared to the unstained transparent individuals. We conclude that the transparent body form is of great significance in escaping predation during the larval phase of life in M. ornata.

Diverse alveolate infections of tadpoles, a new threat to frogs?

Diverse alveolate infections of tadpoles, a new threat to frogs?

Enormous frogs heave rocks to build tadpole ‘nests’

Enormous frogs heave rocks to build tadpole ‘nests’

Tadpole appearance: Azygous fissure.

Tadpole appearance: Azygous fissure.

Natural history and conservation of the Nurse Frog of the Serranía del Perijá Allobates ignotus (Dendrobatoidea: Aromobatidae) in northeastern Colombia

We describe new findings on the geographic distribution, habitat uses, relative abundance, tadpoles, and advertisement call of Allobates ignotus . Data of habitat uses and relative abundance were collected during five annual fieldtrips of seven days each one, from April 2010 to June 2014, in a mining zone of Canime Creek Basin, La Jagua de Ibirico, Cesar Department, northeast Colombia. Tadpoles and advertisement call were obtained in La Veguita Creek Basin, Manaure Balcon del Cesar, Cesar. We report six new localities with presence of A. ignotus , all between 7-96 km in straight line to the type locality, from 194-1236 m a.s.l. This species is recorded for the first time in the Tropical Dry Forest Life Zone and in La Guajira Department. Four substrate categories used by A. ignotus were detected (leaf-litter, rocks, naked floor, and lower branches), and differential use was highlighted. The larval morphology of A. ignotus was described, based on 11 specimens between 25-29 stages. Like other Allobates tadpoles, the gap of the second teeth row is “wide”. The advertisement call of A. ignotus is composed by a series of high frequency ascending pulsed notes. Possibly, the high frequency of the call is due to the acoustic disturbance generated by the streamflow noise of the creeks. In 2014, a decrease of relative abundance of A. ignotus in Canime Creek was detected. This, coupled to restricted distribution and loss of habitat quality are sufficient criteria to suggest the category of vulnerable for A. ignotus .

Acute Toxicity of Colloidal Silicon Dioxide Nanoparticles on Amphibian Larvae: Emerging Environmental Concern

Fil: Lajmanovich, Rafael Carlos. Universidad Nacional del Litoral; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas; Argentina

Evaluation of the anti-proliferative and cytotoxic potentials of fractions of methanol leaf extract of Cnidoscolus aconitifolius

The partitioned aqueous and chloroform fractions obtained from the methanol extract of the leaf of Cnidoscolus aconitifolius were examined for anti-proliferative (1-30 mg/mL) and cytotoxic activities (20-400 μg/mL) using the seed radicle inhibition and tadpole mortality assays over a period of 24 and 96 h respectively. The vacuum liquid chromatographic sub-fractions of the active chloroform fraction weresimilarly evaluated at 1-10 mg/mL and 5-20 μg/mL concentrations respectively. At 100 μg/mL the chloroform fraction produced 86.67 % mortality which increases to 100 % at 400 μg/mL where the aqueous fraction gave 36.67 %. The potency was further increased as the VLC sub-fractions C4-C6, gave 33 % cytotoxicity at 5 μg/mL and which later increased to 100 % at 10 μg/mL. At the end of 96 h, the control seed had average length of 32.32 ± 2.73 mm compared to 1.92 ± 0.36 and 0.52 ± 0.36 mm observed in the seeds treated with 20 and 30 μg/mL of the chloroform fraction indicating 94.01 and 98.39 % inhibition where as there was total radicle growth inhibition (100 %) of seeds treated with 5 mg/mL of the active VLC sub-fractions (C1-3, C4-C6 and C7). The results showed a significant cytotoxic and growth inhibitory effects of the plant extract, particularly the chloroform fraction and its sub-fractions which further corroborate the folkloric use of the plant in treating cancer. However, further chromatographic analysis of the active VLC sub-fraction and their respective biological studies using cancer cell-lines are needed to support this.Keywords: Cnidoscolus aconitifolius, Sorghum bicolor, anti-proliferative, cytotoxicity, methanol extract, aqueous fraction, chloroform extract , vacuum liquid chromatography,

Observations on the intraspecific variation in tadpole morphology in natural ponds

Intraspecific morphological variation of anuran tadpoles occurs in response to several factors. Causes and consequences of this variation have been largely studied hitherto in controlled environments, but data from natural habitats is clearly less abundant. Here, we present a series of observations on the morphology – mainly tail depth – of three tadpole species from NE Iberian Peninsula across different pond typologies. According to experimental data on tadpole morphology and selective pressures along the pond permanency gradient, we should expect that tadpoles inhabiting ponds with a short hydroperiod – mainly facing desiccation risk – have shallower tail fins than tadpoles from ponds with longer hydroperiod – mainly facing predation risk. Thus, we expected that the link between these complementary selective pressures – predation risk, desiccation risk – and hydroperiod could make possible to detect intraspecific variation in tadpole morphology among different typologies of natural ponds. Morphological differences were found in all studied species, and variation, when present, agreed with theory: tadpoles had deeper fin tails as they were collected in ponds with a longer hydroperiod. Interestingly, in most cases these morphological differences were more marked as tadpoles were larger in size. Although distances among the studied ponds were generally short – posing phenotypic plasticity as the most plausible proximate mechanism – specifically designed studies would be needed to disentangle the relative role of other processes like local adaptation.

Influence of desiccation threat on the metamorphic traits of the Asian common toad, Duttaphrynus melanostictus (Anura)

Phenotypic plasticity of metamorphic traits, in response to desiccation threat, was studied in Duttaphrynus melanostictus under laboratory conditions. Newly hatched Gosner stage 19 tadpoles were exposed to decreasing water levels (gradually or rapidly) up to the beginning of metamorphic climax (MC, Gosner stage 42). The control group was reared in unchanging water levels. The tadpoles experiencing desiccation threat reached MC earlier than those reared in constant water levels and metamorphosed (Gosner stage 46) at smaller body sizes. Time to reach MC was comparable between the groups of tadpoles experiencing a gradual or rapid decrease in water levels but their size at the completion of metamorphosis varied. They emerged at a significantly smaller size under rapid desiccation threat compared to the gradual desiccation threat. Impact on size at emergence was in proportion to the level of desiccation threat and this accelerated development and led to an early metamorphosis. The study shows the ability of D. melanostictus for developmental plasticity under adverse ecological conditions like the desiccation threat.

A New Species of Tree Frog, Genus Phyllomedusa, from Costa Rica

A new species of tree frog, Phyllomedusa annae, is described from Tapanti, Cartago Province, Costa Rica. The new species has blue flanks and thighs and an orange eye; it is closely related to P. moreleti, which has orange flanks and thighs and a red eye. Eggs, tadpole development, and call are also described and illustrated

Toad tadpoles turn homegrown poisons on each other

Young amphibians are the first animals thought to use toxins against rivals of their own species.

Water pollution monitoring of the Lujan River (Argentina): chemical analyses and hepatic biomarkers in Lithobates catesbeianus tadpoles

Fil: Ossana, Natalia Alejandra. Consejo Nacional de Investigaciones Cientificas y Tecnicas; Argentina. Universidad Nacional de Lujan. Departamento de Ciencias Basicas. Programa de Ecofisiologia Aplicada; Argentina

The unexpectedly dull tadpole of Madagascar’s largest frog, Mantidactylus guttulatus

The Madagascar-endemic mantellid genus Mantidactylus contains one subclade with two described frog species characterized by very large body sizes. This subclade is classified as the subgenus Mantidactylus and is widespread in eastern and northern Madagascar, but their reproductive biology and larval stages are still unknown. We here provide a detailed description of the larvae of one species in this subgenus, M. guttulatus , on the basis of genetic assignment (16S DNA barcoding). The tadpoles were collected in the dry season from shallow waters near a stream in the Mahajanga Province in northwestern Madagascar. Their body and tail shape is remarkably generalized as typical for stream-adapted tadpoles, and the oral disc and labial keratodont row formula (4(2-4)/3(1)) are similar to those of other lotic mantellid frog larvae with generalized mouthparts like those in the subgenus Brygoomantis . The well-separated positions of these subgenera in the mantellid phylogeny suggest extensive homoplasy in the evolution of larval mouthpart morphology within Mantidactylus.

Rhinella major (Anura: Bufonidae) and Leptodactylus macrosternum (Anura: Leptodactylidae): predation and cannibalism by Leptodactylus macrosternum

Cannibalism among anurans has been documented for many species, both on eggs, tadpoles and post-metamorphic specimens. Here we make note of cannibalism among Leptodactylus macrosternum at the area flooded, municipality of Santana, State of Amapa, Brazil. The initial observation was prompted by following an distress call, revealed to be emitted by an individual L. macrosternum which was biting the hind limbs of the male L. macrosternum . For approximately 20 min we observed the attempting to cannibalism of the frog. The individuals was collected and placed into a plastic bag and transported to the laboratory for analysis. The stomach contents of L. macrosternum included two anuran species: L. macrosternum and Rhinella major .This is the first report of adult canibalism in this species. Moreover, no evidence of cannibalism could be found even in intensive comparative studies on stomach contents.

Bolder tadpoles spread more disease

Bolder tadpoles spread more disease

Bioaccumulation of Heavy Metals in Anuran Tadpoles: A Study in Barak Valley, Assam

Heavy metal pollution plays an important role in global biodiversity decline. However, there is paucity of information concerning the effects of metals on amphibians. In the present study, investigations were made on the accumulation of heavy metals, copper (Cu) and lead (Pb) in water, sediment and tadpoles inhabiting the water bodies of Barak Valley, Assam. Tadpoles of six different anuran species, Hoplobatrachus tigerinus , Leptobrachium smithi , Clinotarsus alticola , Fejarvarya sp., Sylvirana leptoglossa and Euphlyctis cyanophlyctis were selected for this purpose. Heavy metal concentrations were determined in intestine, liver and tail of tadpole samples of these species. The results revealed that the copper concentration in water samples was within the maximum permissible limit of WHO (2 mg L -1 ), but the concentration of lead in water samples increased beyond the permissible limit of WHO (0.01 mg L -1 ) resulting in possibilities of higher accumulation of the metal in tadpoles and decline of amphibians’ population. Total concentration of Cu in the tadpoles of different species of amphibians followed the order: H. tigerinus > S. leptoglossa > E. cyanophlyctis > C. alticola > Fejarvarya sp. > L. smithi , while concentration of lead followed the order: E. cyanophlyctis > C. alticola > S. leptoglossa > Fejarvarya sp.> H. tigerinus > L. smithi .

Correlation between development and increase of number of labial tooth rows in ghost frog tadpoles (Anura: Heleophrynidae)

The family Heleophrynidae is restricted to Southern Africa and comprises two genera with seven species. Tadpoles are well adapted, with huge sucker mouths, to live in the fast flowing headwaters of mountain streams. The unique sucker-like mouth has numerous transverse rows of labial teeth, which are used to attach themselves to the rock surface and to scrape algae from the rocks. In this paper data on the ontogenetic increase of labial tooth rows in tadpoles of four species of ghost frog are presented. Notes on the development of tadpoles and mouthparts are also presented.

Re-description of the external morphology of Phyllomedusa iheringii Boulenger, 1885 larvae (Anura: Hylidae), with comments on the external morphology of tadpoles of the P. burmeisteri group

Phyllomedusa iheringii is a leaf frog endemic to the Uruguayan Savanna, which reproduces in water bodies in open areas. Here, based on the lack of some informative characteristics observed on the first description of this species, we re-describe the larval external morphology of P. iheringii from localities in Brazil and Uruguay, and compared them with other species from the P. burmeisteri group. The tadpoles of P. iheringii belong to the suspension-rasper guild. The body length corresponds to approximately one-third of the total length. The body is pyriform in dorsal view and laterally triangular. The snout is rounded in a dorsolateral view. The spiracle is single and almost ventral, not forming a free tube, and sinistral. The opening of vent tube is dextral. The oral disc is anteroventral and anteriorly directed, with single ventral emargination. Marginal papillae uniseriate, interrupted in a wide dorsal gap, and with pointed tips. The labial tooth row formula is 2(2)/3(1). The third lower row is four times shorter than the others. Furthermore, the tadpoles of P. iheringii showed morphological differences in relation to other species of the P. burmeisteri group, this species seems to be smaller in average and have fewer marginal papillae in the oral discs.