Structure of the eye of <i>Haideotriton wallacei</i>, a North American troglobitic salamander

Brandon, Ronald A.

doi:10.1002/jmor.1051240307

Cited by 12 publications

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“…Photoreceptors also are degenerate in the pineal body, a photoreceptive organ in the roof of the diencephalon that can be directly sensitive to light (for review see Kalsbeek et al, ), but some opsins are still expressed and likely maintain secretory activity (Kos and Bulog, , , ; Kos et al ). In Eurycea wallacei , the degenerate eye becomes embedded in a mass of adipose tissue and no extrinsic eye muscles are present (Brandon, ). A rudimentary lens is present in some individuals and the retina is undifferentiated.…”

Section: Troglomorphy In Cavefishes and Salamandersmentioning

confidence: 99%

“…Interestingly, changes are initiated only after metamorphosis, although a few larvae can have degenerating retinas. The eyes of the Georgia Blind Salamander Eurycea wallacei are more degenerated than those of other stygobiotic salamanders (Brandon, ), and the small eye is imbedded in a mass of adipose tissue, as in many other cavefishes and cave salamanders. A rudimentary lens is present in about half of the eyes examined by Brandon ().…”

Section: Troglomorphy In Cavefishes and Salamandersmentioning

confidence: 99%

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Extreme Adaptation in Caves

Soares

Niemiller

2018

The Anatomical Record

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Cave adaptation leads to unique anatomical specializations in many taxonomic groups. As the role of vision is reduced or disappears in a subterranean environment, other specializations arise to allow the organism to successfully detect and interact with their environment. A suite of unique, convergent phenotypes associated with subterranean adaptation has emerged (termed troglomorphy), with reduction or loss of pigmentation and eyes being the most conspicuous. Two vertebrate groups that have successfully colonized and adapted to subterranean environments are cavefishes and cave salamanders. There are many shared troglomorphic anatomical characters shared between these two groups, and we describe herein the morphological traits that are unique to fishes and salamanders that are adapted to caves and other subterranean habitats. Troglobionts, animals strictly bound and adapted to underground habitats, are outcomes of not just regressive evolution, but also constructive adaptation. There are skeletal changes, such as broadening and flattening of the head, as well as hypertrophy of non-visual modalities. Cavefishes and salamanders have lost eyes and pigmentation, but also enhanced mechanosenzation, chemosenzation and, in some cases, electroreception. Both cavefishes and cave salamanders have become important models in the study of the ecology, behavior, and evolution of subterranean colonization and adaptation. However, our knowledge is primarily limited to a few taxa and many questions remain to be studied. Anat Rec, 303:15-23, 2020.

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Section: Troglomorphy In Cavefishes and Salamandersmentioning

confidence: 99%

Section: Troglomorphy In Cavefishes and Salamandersmentioning

confidence: 99%

Extreme Adaptation in Caves

Soares

Niemiller

2018

The Anatomical Record

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“…E. ludfuga and T. spelaeus differ in size at metamorphosis and in the extent of postmetamorphic increase in body size ( Fig. I; see also Brandon, 1966Brandon, , 1970Bishop, 1943). E. luciftlga transforms at a snout-vent length of 30-35 mm and may double in length during postmetamorphic growth; throughout this time its eyes increase in size at a regular rate.…”

Section: Resultsmentioning

confidence: 94%

“…Measurements of the eyes of Eurycea tridentifera (Mitchell and Reddell, 1965) and Haideotriton wallacei (Brandon, 1968) indicate that one parameter of eye reduction of these animals is considerable individual variation and bilateral asymmetry. The significance of these observations is not clear, however, since in no case has it been determined whether or not such variation reflects genotypic differences.…”

Section: Size and Growth Of The Eyes Of The Troglobitic Salamander Tymentioning

confidence: 99%

“…The inherent difficulties in genetic analysis among urodele amphibians preclude a quick answer to this question. Typhlotriton spelaeus is the only troglobitic urodele that attains sexual maturity after metamorphosis; the others are paedogenetic (Brandon, 1966;. In addition, T. spelaeus larvae have functional eyes that usually degenerate after metamorphosis (Eigenmann and Denny, 1900;Stone, 1964;Besharse, 1972).…”

Section: Size and Growth Of The Eyes Of The Troglobitic Salamander Tymentioning

confidence: 99%

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1974

IJS

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a language not their own are urgently requested ta have their manuscripts checked for linguistic correctness before submission. All papers should finish (in addition) with an English summary, giving a synopsis of the paper with sufficient detailed information concerning the methods used and the results obtained.3 Papers should be typed in double spacing, on one side of the paper, quarto size. leaving top and left hand margin at least 2.5 cm (one inch) wide.4 Papers should be headed by a title, the initials(s) and name(s) of author(s) and an exact description of the post held and business address of the author(s). Dates should be in the form "5 February 1959".Continuation see inside of back cover.Int. J. Speleol. 6 (1974), pp. 187-192. A (24.3.73). "These three localities are extremely similar. They are three beaches of the Caribbean See, located on the southern coast of the eastern extremity of the Island, at the foot of the Gran Piedra Mountain.The sand of these beaches is mainly of fluviatile origin but there are also many coral fragments in the sand. It is coarse, loose and clean (without much plant detritus). The samples were made by digging holes into the sand ("Karaman-Chappuis sondages") 1-3 m from the wave line and filtering through a net the water which more or less rapidly fills these holes. This water is strongly brackish, anyway less salt than the sea. The temperature of the water filling the holes was 280C (Siboney), 21 0 (Juragua) and nOc (Baconas). The three beaches have very rich and varied interstitial fauna." DESCRIPTIONThe collection consisted of about 25-30 very small animals** (trunk usually about 3 mm long), whitish in colour and semi-to almost completely transparent to transmited light. No eggs were found in the body cavity of any of the specimens so *) Department of Zoology, University of Adelaide, South Australia. **) Some other specimens were not sent to me but remained in the collections of the Institute of Speology, Bucharest. 188 S. J. EDMONDSthat it is difficult to say whether they were adults. The body wal1 was so thin and the specimens so smal1 that the animals were difficult to dissect. Fig. 1 was drawn from an undissected specimen.Trunk more or less cylindrical with smooth skin; length 1-5-4.2 mm and width 0.4-0.9 mm. Anal (anterior) and caudal (posterior) shields pale yel10w in colour and composed of smal1 polygonal plates. Shields without furrows. In about eight specimens the caudal shield is poorly developed and appears to be rudimentary or even absent.Introvert fine, in the ful1y extended condition up to 15 mm long and much longer than the trunk. It arises eccentrical1y from the trunk, ventral to the anal shield. Anteriorly it is armed with 20-24 rows of very small, clear, double-pointed hooks; at the base of each hook are a number of curved bars. Spines are absent though at least in four specimens a few, single pointed clear hooks, about the same size as the double pointed ones, were sparsely distributed posterior to the region which bears the rows of doubled pointed ho...

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Photoreceptor degeneration in the eyes of an amphisbaenian in response to constant light or constant darkness

Gundy

1977

J. Exp. Zool.

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Eye morphology and behavioral responses were studied in Bipes biporus (Cope) exposed to normal photoperiods, constant light, and constant darkness. Control animals had retinas with a reduced number of outer segments relative to the typical vertebrate retina. In addition, many of these outer segments were poorly formed, suggesting a capability for light detection but not for image formation. Constant light led to detached retinas and eventual degeneration of outer segments. Earliest signs of detachment appeared in younger animals, but no subsequent age differences were found. Constant dark-induced changes were similar to light-induced changes except that dark-induced changes were not so severe, did not depend on age, and included loss of pigment from cells in the pigmented epithelium. Retinal damage in constant dark animals suggests that free-living Bipes biporus are occasionally exposed to light. Dark-seeking behavior of normal animals diminishes after exposure to constant light.Light deprivation leads to retinal damage in chimpanzees, cats, and rats (Chow et al., '57; Rasch et al., '61). Continuous light has similar effects (Kuwabara, '66; Noell et al., '66a,b). Since these initial reports, light-induced retinal degeneration has been welldocumented in several strains of laboratory rats (see Saavedra and Pellegrino de Iraldi, '76 for references). Similar results have been obtained in wild-strain kangaroo rats, hamsters, Swiss mice, Galago monkeys (Noell and Albrecht, '71), Rhesus monkeys (Friedman and Kuwabara, '68; Ham and Mueller, '76; Tso, ,731, '731, birds (Kuwabara and Gorn, '68) and in humans (Ts'o et al., '74).Very little is known about the effects of constant light and light deprivation on reptiles. I therefore undertook such a study, using the "worm lizard" or "ringed lizard" of Baja, California, Bipes biporus (Cope). Bipes is no longer classified as a lizard, but is a member of the suborder Amphisbaenia. This animal is highly specialized for burrowing. The worm-like body has reduced eyes, minimal pigmentation, reduced forelimbs, and no hindlimbs, suggesting a life-style with little exposure to light. My objectives were to describe the eye morphology occurring under these light-poor conditions, and to investigate the structural and behavioral effects of constant light and constant darkness. MATERIALS AND METHODS Seventeen 170G . CRAIG GUNDY the bottom of the box, was 23-26°C. Constant dark animals were maintained in plastic boxes with no sand. Temperature, measured by a thermometer lying in the bottom of the box, was 22-25°C. Temperature readings in the three boxes were never found to differ by more than 1°C. All animals in the control, constant light and constant dark groups were watered but none were fed during the 8-week duration of this experiment.Dark-seeking behavior was tested during a separate 10.8-week experiment using an open arena 26 cm in diameter ringed by eight compartments (total diameter 41 cm). Two of these compartments were located 180" from each other and were dark. The ...

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Structure of the eye of Haideotriton wallacei, a North American troglobitic salamander

Cited by 12 publications

References 12 publications

Extreme Adaptation in Caves

Extreme Adaptation in Caves

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Photoreceptor degeneration in the eyes of an amphisbaenian in response to constant light or constant darkness

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