Skeletochronological Study Research Articles

Age Structure and Growth Rate of the Triploid Batura Toad, <i>Bufotes baturae</i> (Anura: Bufonidae), Inhabitant of a High Altitude Hot Spring in the Eastern Pamirs (Tajikistan)

The paper reports the results of the first skeletochronological study of age structure and distinguishing characteristics of growth in the triploid toad Bufotes baturae, inhabitant of Sasyk-Bulak hot spring in the Pamir Mountains (3797 m a.s.l.). Minimal and maximum ages of males of the species were three and seven years, respectively. The age of females ranged from three to six years. Mean age for both sexes was 4.0 years. The majority of males (46.2%) were three years old, most females (58.8%) were four years old. The age of sexual maturity was reached after three hibernations (46% in males and 24% in females). The majority of toads breed once at the age of three or four years. Only few (18% in females and 23% in males) individuals in this population were older. Harsh high-altitude cold desert conditions and limited food resources may cause high mortality of the toads. The correlation between the minimal age at sexual maturity and the degree of dryness of climate was demonstrated among species of the genus Bufotes. As a rule, toads which live in more humid climatic conditions mature earlier. Perhaps, this explains that substantial part of semi-aquatic individuals of B. baturae in the hot spring mature at earlier age (3 years) than other polyploid species (4 – 5 years) that inhabit arid environments. In both sexes of B. baturae, growth rate was similar to that of other closely related high-mountain species, diploid B. latastii and triploid B. pseudoraddei.

Life history and ossification patterns in Miguashaia bureaui reveal the early evolution of osteogenesis in coelacanths.

The study of development is critical for revealing the evolution of major vertebrate lineages. Coelacanths have one of the longest evolutionary histories among osteichthyans, but despite access to extant representatives, the onset of their weakly ossified endoskeleton is still poorly understood. Here we present the first palaeohistological and skeletochronological study of Miguashaia bureaui from the Upper Devonian of Canada, pivotal for exploring the palaeobiology and early evolution of osteogenesis in coelacanths. Cross sections of the caudal fin bones show that the cortex is made of layers of primary bone separated by lines of arrested growth, indicative of a cyclical growth. The medullary cavity displays remnants of calcified cartilage associated with bony trabeculae, characteristic of endochondral ossification. A skeletochronological analysis indicates that rapid growth during a short juvenile period was followed by slower growth in adulthood. Our new analysis highlights the life history and palaeoecology of Miguashaia bureaui and reveals that, despite differences in size and habitat, the poor endoskeletal ossification known in the extant Latimeria chalumnae can be traced back at least 375 million years ago.

Age Structure of the Caucasian Agama (<i>Paralaudakia caucasia</i>) from Elmadağ, Iğdır, Turkey: Preliminary Data from Small Sample Size

Life history traits of lizard species, including agamid species, generally involve male-larger body size, but age of these species has not adequately been examined in each cohort. We thus conducted a skeletochronological study using 16 preserved specimens of Paralaudakia caucasia (8 males, 6 females, and 2 juveniles) captured from Elmadağ, Iğdır, Turkey. Mean snout-vent length was slightly but insignificantly larger in males (120.2 mm) than in females (115.9 mm). Maximum longevity was 10 years in males and 6 years in females. No significant difference in age structure was found between the sexes. Juveniles were 2-year old young. Mean age was 7.12 years for males and 5.33 years for females. Sexually matured individuals were found at the end of the second or third years (i.e., first reproduction occurred at 3 – 4 years). A positive correlation was detected in age and body size in both sexes, as has previously been shown in other lizard species. Our finding of age structure in P. caucasia would contribute to our understanding of life-history trait variations among lizard species.

Age Structure of the Caucasian Agama (<i>Paralaudakia caucasia</i>) from Elmadağ, Iğdır, Turkey: Preliminary Data from Small Sample Size

Life history traits of lizard species, including agamid species, generally involve male-larger body size, but age of these species has not adequately been examined in each cohort. We thus conducted a skeletochronological study using 16 preserved specimens of Paralaudakia caucasia (8 males, 6 females, and 2 juveniles) captured from Elmadag, Igdir, Turkey. Mean snout-vent length was slightly but insignificantly larger in males (120.2 mm) than in females (115.9 mm). Maximum longevity was 10 years in males and 6 years in females. No significant difference in age structure was found between the sexes. Juveniles were 2-year old young. Mean age was 7.12 years for males and 5.33 years for females. Sexually matured individuals were found at the end of the second or third years (i.e., first reproduction occurred at 3 – 4 years). A positive correlation was detected in age and body size in both sexes, as has previously been shown in other lizard species. Our finding of age structure in P. caucasia would contribute to our understanding of life-history trait variations among lizard species.

A skeletochronological study of age, growth and longevity in two freshwater turtles, Emys orbicularis and Mauremys rivulata, from Mediterranean Turkey (Reptilia: Testudines)

We estimated growth parameters of Emys orbicularis and Mauremys rivulata in Mediterranean Turkey with the skeletochronological method, using specimens drowned in fyke nets. In adult E. orbicularis, the median age was 8 years in males and 10 years in females. The median age of adult M. rivulata was 10 years for both sexes. Both species reach sexual maturity at an age of 5–7 years. No difference was found in age composition between the sexes.

A skeletochronological study of the smooth newt Lissotriton vulgaris (Amphibia: Urodela) from an island and a mainland population in Turkey

To understand the effects of island and mainland on life history traits (e.g. longevity, age at maturity, body size and body mass) of the smooth newt Lissotriton vulgaris (Linnaeus, 1758), we generated data on age and body measurements for an island (Bozcaada) and a mainland (Çanakkale) population in northwestern Turkey. Age was determinated by skeletochronology. The maximum life span was 4 years in the island population and 5 years in the mainland population. Age at maturity was estimated to be 2–3 years for both sexes and the populations. While mean snout-venth length (SVL) was calculated as 35.56 mm for females and 31.95 mm for males in the mainland population, it was found to be 32.83 mm for females and 31.78 mm for males in the island population. Females from the mainland population were found to be significantly larger and heavier than those of the island population. A significant positive correlation was found between SVL and age for only males in the mainland population. Unexpectedly, age was not correlated with body size for the island individuals. Since there were hardly any demographic studies on any Urodela species comparing island and mainland populations, in this paper we contribute to the literature on this subject.

The Study of Age, Growth, and Longevity in the Triploid Hybrids of Rock Lizards of the genus Darevskia in Armenia

Skeletochronological study of rock lizards hybrids Darevskia valentini × D. unisexualis , D. valentini × D. armeniaca , D. nairensis × D. unisexualis , and their parental species, collected from three mixed populations (near village of Kuchak, Lchashen, Lchap — mountainous regions of central Armenia) proved their similar pattern of growth. However, the hybrids are characterized by faster rate of growth and predominantly bigger size of body in each age group contrary to their parental species. The longevity of studied hybrids is same as in parental species and reaches 6 – 7 years.

A skeletochronological study of age, growth and longevity of Rana macrocnemis populations from four locations at different altitudes in Turkey

Abstract We examined life-history traits such as population age structure, growth and longevity of Iranian Long-Legged frogs (Rana macrocnemis) from 4 different locations at different altitudes in Turkey by skeletochronology performed on the phalanges. The maximum lifespan was 5 years in Maçka (350 m a.s.l.), 6 years in Hıdırnebi (1430 m a.s.l.), 8 years in Sarıkamış (2276 m a.s.l.) and 10 years in Ovit (2850 m a.s.l.). Age at sexual maturity of both males and females was 2-3 years in the Maçka, Hıdırnebi and Sarıkamış populations, while 3-4 years for males and 3-5 years for females in the Ovit population. In all populations, males and females did not exhibit any differences in terms of mean age and SVL except for Sarıkamı¸s where the males were significantly larger than the females. A positive correlation was observed between age and SVL for both sexes in all populations except for the males of the Maçka population.

A Skeletochronological Study of the Age Structure, Growth, and Longevity of the Mountain Yellow-legged Frog, Rana muscosa, in the Sierra Nevada, California

We used skeletochronology to determine the ages of 149 (74 females, 44 males, and 31 juveniles) Mountain Yellow-legged Frogs (Rana muscosa) from 13 locations (elevation 1509–3501 m) throughout their current range in the Sierra Nevada mountains of California. Lines of arrested growth (LAGs) from excised toe bones were distinct in these high elevation frogs, and each LAG was assumed to represent one year of age. Females ranged in age from 0–10 years (mean = 4.1 years) and males from 0–8 years (mean = 4.0 years). The skeletochronological age was that of the post-metamorphic frog and did not include the tadpole stage. Mountain Yellow-legged Frogs spend 3–4 years as tadpoles, but no age markers are found in their cartilaginous skeletons; thus, their total age, if both tadpole and post-metamorphic stages were included, would range up to 14 years. Females were significantly longer (snout–vent length: SVL) than males and had greater mean mass, but there was no difference in the mean ages. Juvenile frogs of unknown sex ranged in age from 0–3. The von Bertalanffy growth curve demonstrated that female SVLs were larger than males for all ages. Using a semi-parametric growth model, we also found that elevation within the Sierra Nevada range was an important variable in the relationship between SVL and age; frogs from lower elevation sites were consistently larger at a given age when compared to higher elevation sites. For each increase of 1000 m in elevation, the estimated length (on average) decreases by 8.7 mm. This is the first age determination study of a Sierra Nevada amphibian, and compared to other anuran species, Mountain Yellow-legged Frogs were found to be relatively long-lived, which will have implications for restoration and recovery plans.

A skeletochronological study of age, growth and longevity in a population of the frog Rana ridibunda from southern Europe

Age at sexual maturity and longevity in a population of Rana ridibunda from north-eastern Greece were studied by skeletochronology performed on the phalanges. Analysis of the age structure was based on counting the lines of arrested growth (LAGs). Sexual maturity for both sexes arises during the first year or after the first hibernation. Ages ranged from 1 to 5 years (mean=2.96) among 52 males and from 1 to 5 years (mean=3.73) among 56 females. The mean snout-vent length was 69.03±12.6mm in males and 82.38±13.27mm in females. The difference between the sexes in age and size was significant. Growth of individuals was fitted on? The von Bertalanffy model. The growth coefficient (K) was 0.57 in males and 0.54 in females, mainly due to faster male growth between metamorphosis and maturation.

A Skeletochronological Study on a Subtropical, Riparian Ranid (Rana swinhoana) from Different Elevations in Taiwan

We estimated the age, longevity, and growth patterns of a subtropical ranid, Rana swinhoana from high (Lishing) and low (Wulai) elevations using skeletochronology. In addition, we also measured body mass and length of frogs from five other localities. Results showed that both snout-vent length and body mass of frogs were significantly correlated with altitudes for both sexes. Frogs of Lishing were significantly larger and older than that of Wulai. We used LAGs to estimate the age and growth of frogs and found that the growth of Wulai frog of both sexes slowed down at an earlier age than that of Lishing frogs. Male and female frogs from Wulai did not exceed 6 and 7 years, respectively, while the maximum age of males and females of Lishing was 7 and 11 years, respectively. Results suggest that the LAGs observed in R. swinhoana correspond to low temperature and/or decreased food availability instead of desiccation during the harsh annual period (November to February). Skeletochronological data suggest that the variations of body size of R. swinhoana among elevations are likely associated with the growth, age at sexual maturity, and longevity.

A skeletochronological study of growth, longevity, and age at sexual maturity in a population of Rana latastei (Amphibia, Anura).

Longevity and age at sexual maturity in an Italian population of Rana latastei were studied by skeletochronology performed on the phalanges. Frogs collected in 1998 and 1999 by drift fences and pitfall traps were marked by toe-clipping. After marking, individuals were released and the cut phalanges were processed for skeletochronological analysis. The maximum age so far recorded was 3 years in males and 4 years in females. The smallest male and female that were sexually mature on the basis of histological analysis of the gonads were 36 and 35 mm snout vent length (SVL), respectively. In both sexes, most individuals were estimated to breed shortly after emergence from their first overwintering. Among the European Brown Frogs, Rana latastei appears to be one of the shortest-lived and one of the first to reach sexual maturity.

A skeletochronological study of age and growth in relation to adult size in the water frog Rana epeirotica

The age and growth of individuals in a population of the water frog Rana epeirotica, from northwestern Greece, were studied in 1998 and 1999 using skeletochronology. Analysis of the age structure was based on the enumeration of Lines of Arrested Growth (LAGs) in phalanges. Ages ranged from 1-5 years among 145 males and from 1-5 years among 173 females. The mean snout-vent length was 72.74 +/- 7.96 mm in males and 83.63 +/- 11.73 mm in females. The difference between the sexes in age and size was significant. Endosteal resorption may have eroded away the first LAG in only 9% of the studied individuals and was more frequent in females. Growth of adults was fitted by the Bertalanffy model. The growth coefficient (K) was 0.88 in males and 0.49 in females, reflecting faster male growth between metamorphosis and maturation.

From Reindeer to Wallaby: Recovering Patterns of Seasonality, Mobility, and Prey Selection in the Palaeolithic Old World

Data regarding major human prey from Franco-Cantabrian Palaeolithic sites have been gained through skeletochronological analyses. Trends gleaned from these data suggest temporal shifts in mobility, territoriality, and subsistence strategies. Compilation of control samples of teeth of recent animals (e.g., Cervus, Rangifer, Equus, Capreolus, Bos) of known-age and date-of-death has been requisite to these growth-increment studies. These methods have now been applied to modern Bennett's wallaby (Macropus rufogriseus) populations from Tasmania in order to expand the potential of skeletochronological study for Australia's Palaeolithic-aged marsupial archaeofaunas.

Histological Observations of Cementum Growth in Horse Teeth and their Application to Archaeology

This paper presents results from a skeletochronological study of horse ( Equus caballus). The application of cementum incremental studies on modern and fossil equids is examined based on a control sample of horses of known date of death. Observation and preparation techniques used include transmitted polarized light and scanning electron microscopy, microradiography and the preparation of decalcified, stained sections. Fossil remains were obtained from Upper Palaeolithic sites in southwestern France (Dryas I occupation levels). The results show that skeletochronology is an important archaeological tool, permitting the obtention of seasonal indices for prehistoric sites.

A Skeletochronological Study of Growth and Age in Relation to Adult Size in Batrachoseps attenuatus

A Skeletochronological Study of Growth and Age in Relation to Adult Size in Batrachoseps attenuatus