Seasonal Changes in Body Shape and Mass in the Salamander, Hynobius nigrescens

Hasumi, Masato; Iwasawa, Hisaaki

doi:10.2307/1564217

Cited by 19 publications

(14 citation statements)

References 13 publications

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“…By contrast, in ambystomatids distributed widely in North America (i.e., a counterpart of hynobiids distributed in Asia), sexual selection on body size is lacking (Williams and DeWoody 2009). This may lead to the absence of substantial attention to the interaction of size dimorphism to a difference in shape even in Hynobius and Triturus species with drastically increased BSSD traits during the aquatic phase (Hasumi and Iwasawa 1990;Malmgren and Thollesson 1999). Speculating their interaction as suggested and hypothesized here will thus contribute to considering determinants of SSD.…”

Section: Discussionmentioning

confidence: 87%

“…Unlike terrestrial plethodontid salamanders (Maerz et al 2006), in many migratory amphibians, clarification of BSSD traits that alternate between aquatic and terrestrial phases of the life cycle is a considerable contribution to our understanding of the evolution of complex life cycles (Malmgren and Thollesson 1999;Pough et al 2001;Salvidio and Bruce 2006). For example, a noticeable increase in head width, resulting from the swelling of the whole body of the male during the aquatic phase, is related to male-male competition and is unknown in families other than hynobiids that accomplish external fertilization (Hasumi and Iwasawa 1990;Hasumi 1994Hasumi , 2001a. In addition to increased head width, male S. keyserlingii had a longer tail than females in size and shape (i.e., sexually dimorphic trait) and had a longer tail in the aquatic phase than in the terrestrial phase (i.e., biphasically dimorphic trait).…”

Section: Discussionmentioning

confidence: 99%

“…Third, how important is biphasic, sexual shape dimorphism (BSSD) for determinants of SSD? Biphasic characteristics are those that differ between adult aquatic-and terrestrial-phase morphs, and shape is size of a characteristic relative to body size (Hasumi and Iwasawa 1990). To address these questions, I generated data on lines of arrested growth (LAG) for age estimation in Salamandrella keyserlingii Dybowski, 1870, using monthly samples from spring to fall over three consecutive years (Hasumi and Kanda 2007).…”

Section: Introductionmentioning

confidence: 99%

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Age, Body Size, and Sexual Dimorphism in Size and Shape in Salamandrella keyserlingii (Caudata: Hynobiidae)

Hasumi

2010

Evol Biol

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In organisms with determinate growth, sexual size dimorphism (SSD) occurs before maturity during the developmental process of growing apart, an ontogenetic perspective on the evolution of SSD. If the direction of SSD (female-larger SSD) is known, patterns of growth can be tested with one-tailed statistical distributions. In indeterminate growing organisms as well, does SSD occur before maturity? If it occurs, whether is females' larger mean body size caused by a difference in age at maturity, age-specific size, divergent growth prior to maturity, or selection on post-maturational growth? How important is biphasic, sexual shape dimorphism (BSSD) for determinants of SSD? Biphasic characteristics are those that differ between adult aquatic-and terrestrial-phase morphs, and shape is size of a characteristic relative to body size. To address those questions, I determined age and body size based on a careful description of a growth trajectory for each sex in Salamandrella keyserlingii, using 555 independent data points from skeletochronological studies. Females reached maturity at 3-4 years of age, a year later than males that reached maturity at 2-3 years of age (mean body size: males = 57.63 mm, females = 61.70 mm; delayed sexual maturity resulted in SSD). However, SSD was highly detected before maturity (SSD index = 0.097), and females after maturity continued to grow and resulted in larger asymptotic size than males. Traits of BSSD were greater in males than in females. These results suggest that when determining SSD the difference in mean adult-body size results from the difference in age-specific size and the female-larger SSD develops to resolve intersexual ontogenetic conflict by allowing small-sized males to swell their whole body during the aquatic phase as much as large-sized females.

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Section: Discussionmentioning

confidence: 87%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Age, Body Size, and Sexual Dimorphism in Size and Shape in Salamandrella keyserlingii (Caudata: Hynobiidae)

Hasumi

2010

Evol Biol

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“…Reversible changes in morphology during the reproductive aquatic phases of urodeles are well known, for example the development of crenulated crest and pronounced tail fins in males of Triturus spp. (Halliday 1977), and large increase in body mass, head width, and tail height in Hynobius nigrescens males (Hasumi and Iwasawa 1990). Halliday (1977) and Hasumi and Iwasawa (1990) posit that when urodeles undergo an increase in surface area, their ability to absorb oxygen from the water also increases, therefore they probably remain underwater for longer periods of time, thus increasing their chances of successful breeding.…”

Section: Introductionmentioning

confidence: 99%

Relationship between morphotypes of Atelognathus patagonicus (Anura, Neobatrachia) and environmental conditions: evidence and possible explanation

Cuello¹,

Úbeda²,

Bello³

2008

Phyllomedusa

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Relationship between morphotypes of Atelognathus patagonicus (Anura, Neobatrachia) and environmental conditions: evidence and possible explanation. The frog Atelognathus patagonicus (Gallardo, 1962) is endemic to an endorheic pond system in basaltic basins, in Laguna Blanca National Park and its surroundings, in northwest Argentinean Patagonia. The species has two morphotypes, aquatic and littoral, which were studied in Laguna Batea, a semi permanent pond. Aquatic and terrestrial samples were taken over a period of 31 months, including periods of drought and periods of normal precipitation. Evidence was found of the reversible character of the two morphotypes. The changes in the phenotype were consistent with the water level and limnological conditions in the pond. We believe that the change and subsequent reversal of the somatic features in these frogs are an opportunistic alternative showing remarkable plasticity of the species, which can thus inhabit both permanent and temporary ponds. Therefore, the two morphotypes, aquatic and littoral, cannot be considered as "fixed forms" within a given population, as other authors have speculated, and do not correspond to ontogenetic states.

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“…It is well known in hynobiid species that morphological traits associated with breeding (e.g., body mass, head width, tail height, tail length) change drastically at the transition from terrestrial‐phase morphs to aquatic‐phase morphs during spring, irrespective of lentic breeding (e.g., Hynobius nigrescens : Hasumi, ; Hasumi & Iwasawa, ; Hynobius retardatus : Aoto, ; S. keyserlingii : Hasumi, 2001b, ; Hasumi & Borkin, ) or lotic breeding ( Onychodactylus japonicus : Akita, ). Increased head width of the male during the aquatic‐breeding phase, that is, a reproduction‐related morphological trait resulted from the swelling of the whole body, is unknown in other families (Hasumi & Iwasawa, ; for a review, see Hasumi, ). For example, in aquatic‐breeding male salamandrids, body mass increases, and tailfin develops, but head width does not increase at all (Mazzi & Vellano, ).…”

Section: Introductionmentioning

confidence: 99%

A lotic‐breeding salamander (Hynobius kimurae) modifies physiological and morphological traits during wintering

Kakegawa

Hasumi²

2017

Acta Zoologica

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Unlike other migratory salamanders, Hynobius kimurae moves to aquatic hibernacula during fall. Does submergence into water during fall induce changes in physiological and morphological traits? We investigated whether such changes occur in both sexes from the entrance into the water (November) to the exit from the water (May) in the laboratory. Mean duration of stay in the water was 21.7 weeks in males and 19.0 weeks in females. Spermiation began 13.8 weeks after the males entered the water. Sperm storage lasted for 6.3 weeks. Spawning occurred 18.3 weeks after the females entered the water. Cloacae swelled greatly soon after the sexes entered the water. In males after entering the water, tail shape changed from sticklike to finlike. Although physiological and morphological traits in other species change simultaneously in both the submergence into water and the onset of breeding activity only during spring, such changes occurred in individual H. kimurae firstly during fall (shortly after entering the water) and secondly during spring (shortly after awaking from hibernation). This difference suggests that these two‐step changes during a prolonged period (fall–spring) are concentrated in a short period of aquatic‐breeding activity during spring in other species with terrestrial hibernation and associated reproductive cycles.

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Seasonal Changes in Body Shape and Mass in the Salamander, Hynobius nigrescens

Cited by 19 publications

References 13 publications

Age, Body Size, and Sexual Dimorphism in Size and Shape in Salamandrella keyserlingii (Caudata: Hynobiidae)

Age, Body Size, and Sexual Dimorphism in Size and Shape in Salamandrella keyserlingii (Caudata: Hynobiidae)

Relationship between morphotypes of Atelognathus patagonicus (Anura, Neobatrachia) and environmental conditions: evidence and possible explanation

A lotic‐breeding salamander (Hynobius kimurae) modifies physiological and morphological traits during wintering

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