Comparison of the effectiveness of phalanges vs. humeri and femurs to estimate lizard age with skeletochronology

Comas, Mireia; Reguera, Senda; Zamora‐Camacho, Francisco Javier; Salvadó, Humbert; Moreno‐Rueda, Gregorio

doi:10.32800/abc.2016.39.0237

Cited by 21 publications

(20 citation statements)

References 6 publications

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Section: Methodsmentioning

confidence: 99%

“…For age estimation, we evaluated phalanges by means of skeletochronology ( Comas et al, 2016 ). Phalanx skeletochronology is a non-destructive method to estimate age based on the indeterminate growth patterns of ectotherms’ bones, with an estimated precision of one year ( Comas et al, 2016 ). Indeed, in a population of E. calamita toads in Southern Spain, where circa-annual activity patterns are similar to those in this study, skeletochronology has a precision of one year in individuals whose actual age was known by means of mark-recapture ( Tejedo, Reques & Esteban, 1997 ).…”

Section: Methodsmentioning

confidence: 99%

“…With a ProgresC3 camera, we took several photographs of various representative cross-sections, discarding those in which cuts were unsuitable for examining the LAGs. We selected diaphysis sections in which the size of the medullar cavity was at its minimum and that of the periosteal bone at its maximum ( Comas et al, 2016 ).…”

Section: Methodsmentioning

confidence: 99%

“…Because inferring age from the number of LAGs requires knowing the annual number of periods of arrested growth for each year, we calibrated the technique with individuals of known age (six immature individuals which were not included in the analysis), which were within the range from 1 to 2 LAGs, as reported for this species in a low-elevation -as our case is- population ( Oromí, Sanuy & Sinsch, 2012 ). The number of LAGs detected in the periosteal bone was independently counted twice by the same person but on different occasions, always blindly regarding the specimen identification ( Comas et al, 2016 ). Amphibians were collected in winter and spring.…”

Section: Methodsmentioning

confidence: 99%

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Greater reproductive investment, but shorter lifespan, in agrosystem than in natural-habitat toads

Zamora‐Camacho

Comas

2017

PeerJ

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Global amphibian decline is due to several factors: habitat loss, anthropization, pollution, emerging diseases, and global warming. Amphibians, with complex life cycles, are particularly susceptible to habitat alterations, and their survival may be impaired in anthropized habitats. Increased mortality is a well-known consequence of anthropization. Life-history theory predicts higher reproductive investment when mortality is increased. In this work, we compared age, body size, and different indicators of reproductive investment, as well as prey availability, in natterjack toads (Epidalea calamita) from agrosystems and adjacent natural pine groves in Southwestern Spain. Mean age was lower in agrosystems than in pine groves, possibly as a consequence of increased mortality due to agrosystem environmental stressors. Remarkably, agrosystem toads were larger despite being younger, suggesting accelerated growth rate. Although we detected no differences in prey availability between habitats, artificial irrigation could shorten aestivation in agrosystems, thus increasing energy trade. Moreover, agrosystem toads exhibited increased indicators of reproductive investment. In the light of life-history theory, agrosystem toads might compensate for lesser reproductive events—due to shorter lives—with a higher reproductive investment in each attempt. Our results show that agrosystems may alter demography, which may have complex consequences on both individual fitness and population stability.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Greater reproductive investment, but shorter lifespan, in agrosystem than in natural-habitat toads

Zamora‐Camacho

Comas

2017

PeerJ

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“…We followed the skeletochronology methods outlined in the U.S. Geological Survey Protocol (McCreary et al 2008) to determine the age of the lizards. Whereas the femur is the best bone to use for skeletochronological determination of age, Comas et al (2016) demonstrated that the non-lethal method of using phalanges is equally reliable. Skeletochronology has been validated in a closely related species to S. clarkii, the Ornate Tree Lizard (Urosaurus ornatus (Baird in Baird and Girard, 1852)), in the same study plots as the current study using individuals of known age (Paterson and Blouin-Demers 2018).…”

Section: Skeletochronologymentioning

confidence: 99%

Body size, not age, predicts parasite load in Clark’s Spiny Lizards (Sceloporus clarkii)

Watkins

Blouin‐Demers

2019

Can. J. Zool.

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Determining the factors that influence parasite load is a fundamental goal of parasitology. Body size often influences parasite load in reptiles, but it is unclear whether higher levels of parasitism are a result of greater surface area of individuals (a function of size) or of longer periods of exposure to parasites (a function of age). Using skeletochronology in a wild population of Clark’s Spiny Lizards (Sceloporus clarkii Baird and Girard, 1852), we tested the hypotheses that (i) larger individuals have higher parasite loads due to increased surface area available for colonization by parasites and their vectors and that (ii) older individuals have higher parasite loads because they have had longer exposure to parasites and their vectors. Males harboured more ectoparasites than females. Males and females differed in how body size influenced chigger (Acari: Trombiculidae) load; larger males harboured more chiggers than smaller males, but this was not the case in females. Age did not affect ectoparasite load in either sex. These results emphasize the importance of disentangling the effects of size and age in models of parasitism to gain a clearer understanding of intraspecific variation in parasite load.

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Age structure and growth pattern of a high‐altitude lizard population based on age determination by skeletochronology

et al. 2022

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Age determination provides crucial data regarding the life history of a species.Skeletochronology is considered to be a reliable method for age determination but is seldom applied to the genus Phrynocephalus (Agamidae) as it requires careful bone histological analysis to determine the formation of the lines of arrested growth (LAGs). We analyzed LAGs in different bones of Phrynocephalus vlangalii, a small, high-altitude lizard, and demonstrated that the phalanges are the best materials for skeletochronology in this species. We also found that the proximal half of the phalangeal diaphysis exhibits the most complete LAGs because of the unidirectional longitudinal growth of the phalange. Histologically, as the embryo bone that developed during the embryonic period was preserved even in very old individuals, no LAGs were eroded by endosteal resorption in the phalanges. The maximum age was 4 years for males and 5 years for females. It was determined that the age at maturity was 3 years for males and 2 or 3 years for females. On the basis of age determination, the age structures of both sexes were compared, and age-specific growth differences between the sexes were also analyzed. No differences in the snout-vent length were observed between sexes in any age group. However, the tail length of males aged 3 and above was significantly longer than that of females. Thus, the use of phalanges in the age determination of P. vlangalii is effective and can be widely applied to the ecological studies of this species as well as other small lizards.

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Comparison of the effectiveness of phalanges vs. humeri and femurs to estimate lizard age with skeletochronology

Cited by 21 publications

References 6 publications

Greater reproductive investment, but shorter lifespan, in agrosystem than in natural-habitat toads

Greater reproductive investment, but shorter lifespan, in agrosystem than in natural-habitat toads

Body size, not age, predicts parasite load in Clark’s Spiny Lizards (Sceloporus clarkii)

Age structure and growth pattern of a high‐altitude lizard population based on age determination by skeletochronology

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