Suspension feeding of anuran larvae at low concentrations of Chlorella algae (Amphibia, Anura).

Ingestion and filtering rates in larval Xenopus laevis, Bufo calamita, Rana temporia and Bufo bufo fed suspensions of Chlorella fusca were investigated. Concentrations were measured with a Coulter Counter. (1) For all species, filtration occurred at concentrations far below those reported by other authors for Rana sylvatica feeding on Chlorella pyrenoidosa. For Bufo bufo, only larvae near metamorphosis showed ingestion at low particle concentrations. Since buccopharyngeal ventilation continues even in the absence of food particles, this threshold feeding behaviour in the younger larvae must be due to different mechanisms to those found in Daphnia and Calanus studied by other authors: probab…

The filter apparatus of Rana temporaria and Bufo bufo larvae (Amphibia, Anura)

In larvae of Rana temporaria and Bufo bufo the location of filter apparatus within the larval organization, the arrangement of the morphological parts as branchial food trap, ventral velum, and filter rows, as well as their surface anatomy, are similar to that of other species of Orton's larval type IV. The means by which mucous with its entrapped food particles is transported from the filter rows to the esophagus is finally resolved. The dorsally positioned ciliary cushion extends far ventrally between the filter plates. From their contact with the filter rows, the cilia transport the mucous to Kratochwill's caudally positioned “Flimmerrinne” and from there to the esophagus. The original c…

The ontogeny of the filter apparatus of anuran larvae (Amphibia, Anura)

The pharynx ofBufo calamita, Rana temporaria andBombina variegata larvae (larval Types IV and III) changes considerably during the latter part of embryonic development. The entodermal regions between the visceral pockets flatten inward to form the anlagen of the filter plates. The ectoderm thrusts forward from the area of the persistent epidermal gills overlying the anlagen of the filter plates. The esophagus pushes dorsolaterally into the pharynx to give rise to the ciliary cushions. Comparison with the development ofXenopus laevis (larval Type I) reveals shared characters: (1) the filter plates are overlapped by the sensory layer of the epiderm and (2) the ciliary grooves are, like the ci…

The Oral Cavities of Central European Anuran Larvae (Amphibia)

AbstractWith few additions (structures here called prenarial lobes, prenarial arena pustulations, prevalar pustulations), WASSERSUG'S ( 1976) terminology is adequate to describe the oral structures of Central European anuran larvae. The oral cavities of Bombina and Alytes (Discoglossidoidei) are very similar in structure. Based on oral anatomy Pelabates fuscus appears to occupy an intermediate position within the Anura and a basal position among the Ranoidea, which are morphilogical very heterogeneous in oral characters. This assessment is consistent with the findings of other authors working on the anatomy of the tadpole head. Extensive morphological diversity can be found even within the …

Salt tolerance of Rana temporaria: spawning site selection and survival during embryonic development (Amphibia, Anura)

AbstractSpawning site selection of Rana temporaria is dependent on the salinity of the water. In the nature reserve 'Salzwiesen von Münzenberg' (Germany) the frogs avoided increased conductivity values, Cl- ion concentrations and salinities and selected lower values for spawning. In the laboratory Gosner stages 20/21 to 22/23 were more sensitive to sodium than the earlier G stages 8 to 20/21 (exposition for 72 h) though they were exposed for the shorter time period of 24 h. The 'no observed effect concentration' (NOEC) between G stages 8/9 and 20/21 was 648 ppm (3350 μS, 2.2‰ salinity) for Na+ and 1872 ppm (6500 μS, 4.0‰ salinity) for K+. The NOEC between G stages 20/21 and 22/23 was 1490 p…

Do cilia drive water through the buccopharyngeal and opercular cavities in the fossorial Otophryne robusta tadpole?

Functional response of suspension feeding anuran larvae to different particle sizes at low concentrations (Amphibia)

The influence of particle size, initial particle concentration and larval stage on the ingestion rate, ‘retention efficiency’, and filtering rate of anuran larvae with varying filter apparatus anatomy and different life histories was investigated for four species. Larvae of premetamorphic Stages 28 and 32 and prometamorphic Stage 40 were selected for filtering experiments on the basis of their different growth rates. Three different sizes of silica gel particles were offered as mock food. Particle concentration was measured photometrically. The Michaelis-Menten model was used to describe the dependency of ingestion rate, filtering rate, and ‘retention efficiency’ upon initial particle conce…

Die Diagnose der mitteleuropäischen Urodela (Amphibia) nach der Morphologie des Mundhöhlendaches

AbstractThe pattern of teethrows on the roof of the mouth and the numbers of teeth enable as diagnostic characteristics the determination of the Central European Urodela. Particularly the distinction between T. vulgaris and T. helveticus is now definite in all stages after metamorphose. The degree of development of the vomeromaxillarfold (Triturus) respectively of the vomerfold (Salamandra) indicates whether a specimen is an adult, juvenile or newly metamorphosed one.

The stream-dwelling larva of the Ruwenzori River Frog, Amietia ruwenzorica, its buccal cavity and pathology of chytridiomycosis

Tadpoles of Amietia ruwenzorica (Pyxicephalidae, Cacosterninae) were collected in the Ruwenzori Mountains, Uganda(identified by DNA barcoding). The ventrally directed enlarged oral disc with a high number of labial tooth rows (LTRF9(4)/9(1)) and the narrow tail with robust caudal musculature characterise them as stream-dwellers. We name this mor-photype the 'common or standard type of stream-adaptation', because special additional adhesive organs are missing in A.ruwenzorica. The uniserially arranged oral teeth of the spoon-shaped type with 16 to 18 cusps per tooth are known fromother anuran larvae, especially from pyxicephalids. The buccal morphology resembles generalized tadpoles with som…