The discovery of Proteus-eggs (Proteus anguinus Laurenti, Amphibia) in seminatural conditions

Ŝket, Boris; Velkovrh, F.

doi:10.5038/1827-806x.10.2.7

Cited by 9 publications

(7 citation statements)

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“…x Pisces (larvae) vitellus and probably not able to move around in an organised way) speaks in favour of oviparity in P. a. parkelj, as is likely to be the case in P. a. anguinus (Briegleb, 1962;Sket & Velkovrh, 1978). (Culver, 1982).…”

Section: Description Of the Black Proteusmentioning

confidence: 99%

A black, non-troglomorphic amphibian from the karst of Slovenia: Proteus anguinus parkelj n. ssp. (Urodela: Proteidae)

Ŝket

Arntzen²

1994

BTD

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A morphologically distinct cavernicolous salamander Proteus anguinus from southeastern Slovenia (Bela Krajina) is described as P. a. parkelj ssp. n. It differs from P. a. anguinus in a dark pigmentation, fully developed eyes, a skull with broader and shorter bones and fewer teeth, a voluminous jaw musculature that gives the head a bulky appearance, a proportionally longer trunk with a higher number of vertebrae, shorter extremities, and a shorter tail. Most of these traits are considered to be plesiomorphic character states. An allozyme analysis over 40 loci has shown the new dark pigmented taxon to be genetically similar to a white and troglomorphic neighbouring population from Stična (DNei = 0.23). Both populations in turn are genetically dissimilar to a geographically more distant population from Postojna (D Nei = 0.49). The observed level of genetic differentiation suggests that western and southeastern Slovenian populations form separate lineages since the uppermost Miocene but conservatively hitherto only a single species is recognised. The new taxon is only known from a small area and may be rare. P. a. parkelj, now under strict legal protection, is threatened by industrial pollution.

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Section: Description Of the Black Proteusmentioning

confidence: 99%

A black, non-troglomorphic amphibian from the karst of Slovenia: Proteus anguinus parkelj n. ssp. (Urodela: Proteidae)

Ŝket

Arntzen²

1994

BTD

Self Cite

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“…After the discovery of Kammerer committing scientific fraud, some of his results were dismissed by the scientific community of his time, and studies from the 20th century unequivocally report oviparity as parity mode in captively bred olms (Vandel & Bouillon, 1959;Briegleb, 1962;Aljančič & Aljančič, 1998). In addition, the first washed-out eggs were found in the spring near Stična (Sket & Velkovrh, 1978), also suggesting oviparous reproduction in the natural habitat of olms. The mystery seemed solved, if not for the earlier reports of viviparity, and more recently expressed doubts on the alleged fraught by Kammerer; the discovery of epigenetic mechanisms explaining phenotypic plasticity have led some researchers to attempt to rehabilitate Kammerer and his results (Vargas et al, 2017;Nahm, 2021).…”

Section: Historical Notes On Olm Reproductionmentioning

confidence: 84%

“…1). A century and a half later, eggs have been found at this location (Sket & Velkovrh, 1978), refuting the possibility that viviparity was a fixed trait of this lineage. The Stratil protocol contains further inconsistencies, including the observation of a conspicuously large cloaca of the alleged female and pigmented larvae.…”

Section: Discussionmentioning

confidence: 96%

Oviparity, viviparity or plasticity in reproductive mode of the olm Proteus anguinus: an epic misunderstanding caused by prey regurgitation?

et al. 2022

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Cave animals are biological models of fast evolutionary change induced by transition to extreme subterranean environments. But their concealed lifestyle makes it inherently difficult to study life-history changes. Therefore, currently very little is known on the reproduction of cave species, and even less is known on general patterns and potentially shared reproductive strategies. Theory predicts that the cave environment favours the production of a few well-developed offspring and live birth. For one of the most enigmatic cave animals, the olm (Proteus anguinus), it has been debated fiercely whether they reproduce by live birth (viviparity), egg-laying (oviparity) or facultatively. While successes in captive breeding after the 1950s report oviparity as the single parity mode, some historically older observations claimed viviparity. The controversial neo-Lamarckist Paul Kammerer even claimed to have induced changes in parity mode by altering environmental conditions. Here, we report on the feeding and regurgitation of fire salamander (Salamandra salamandra) larvae by olms. The salamander larvae showed clear teeth marks and other injuries on the head caused by the olm, yet one larva was still alive after regurgitation. We suggest that historical reports of olm viviparity could have been misled by regurgitated salamander larvae. Our data bring additional indications that at least some of Kammerer’s experiments were fraudulent.

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“…Oviparity is the common mode of reproduction in olms [ 14 , 15 ], despite questionable reports of ovoviviparity [ 64 , 65 ], possibly provoked by adverse husbandry conditions. According to body mass (14.2 ± 5.2 g; range 7.2 to 24.2 g) and fully developed extremities, all of the olms at Zagreb Zoo were adult, although not all may have reached sexual maturity.…”

Section: Discussionmentioning

confidence: 99%

“…Reproductive success is further reduced by relatively small clutch size (35.2 ± 1.8 eggs) and a low hatching rate (0.4 ± 0.01). Males and females of this typically oviparous species [ 14 , 15 ] are monomorphic; sex determination by external traits is not feasible [ 16 ].…”

Section: Introductionmentioning

confidence: 99%

Monitoring health and reproductive status of olms (Proteus anguinus) by ultrasound

Holtze

Lukač

Cizelj³

et al. 2017

PLoS ONE

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The olm (Proteus anguinus) is a troglomorphic, neotenous amphibian with extraordinary life expectancy and unique adaptations that deserve further investigation. A low reproductive rate and habitat decline render it threatened by extinction. Establishing captive populations for maintenance and artificial breeding may one day become crucial to the species. Longitudinal, in-vivo assessment of inner organs is invaluable to our understanding of reproductive physiology, health, and behavior. Using ultrasound, we measured heart rate and assessed health and reproductive status of 13 captive olms at Zagreb Zoo. Heart rate averaged 42.9 ± 4.6 bpm (32–55 bpm), as determined via pulsed-wave Doppler at 4–12 MHz. By using frequencies of up to 70 MHz (ultrasound biomicroscopy), inner organs were visualized in detail. Assessment of the gastrointestinal tract provided insights into feeding status and digestive processes. Several subclinical pathologies were detected, including biliary sludge, subcutaneous edema, ascites, and skin lesions. Detection of skin lesions by ultrasound was more sensitive than visual adspection. Olms with ultrasonographically detected skin lesions tested positive for Saprolegnia and were treated. Three of the four affected individuals survived and subsequently tested negative for Saprolegnia. Sex was reliably determined; only one individual proved male. The reason for this extreme female-biased sex-ratio remains unknown. However, as most of the individuals were flushed from the caves by strong currents in spring, the sample may not be representative of natural populations. In female olms, different stages of ovarian follicular development were observed with diameters ranging between 0.1 and 1.1 mm. Results were confirmed by comparing ultrasound, necropsy, and histological findings of one dead specimen. In summary, ultrasound proved a valuable tool to support conservation and captive breeding programs by allowing non-invasive assessment of physiological parameters, clinical condition, and reproductive status in olms.

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The discovery of Proteus-eggs (Proteus anguinus Laurenti, Amphibia) in seminatural conditions

Cited by 9 publications

References 1 publication

A black, non-troglomorphic amphibian from the karst of Slovenia: Proteus anguinus parkelj n. ssp. (Urodela: Proteidae)

A black, non-troglomorphic amphibian from the karst of Slovenia: Proteus anguinus parkelj n. ssp. (Urodela: Proteidae)

Oviparity, viviparity or plasticity in reproductive mode of the olm Proteus anguinus: an epic misunderstanding caused by prey regurgitation?

Monitoring health and reproductive status of olms (Proteus anguinus) by ultrasound

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