Incremental Growth Lines Research Articles

Sauropod tail clubs from the Kota Formation (Lower to Middle Jurassic) of India and their implications for early sauropod evolution

ABSTRACT The Lower to Middle Jurassic Kota Formation of India has yielded abundant yet disarticulated skeletal remains attributed to the basally diverging sauropod Kotasaurus yamanpalliensis. The hypodigm of Kotasaurus yamanpalliensis includes four ellipsoidal elements that we identify as tail clubs, based on morphological similarities to tail clubs attributed to two basal sauropods from China: Shunosaurus lii, for which a fully articulated tail series was recovered, and Omeisaurus tianfuensis. Detailed comparison of the Chinese and Indian tail clubs suggests that they are composed of up to three individual elements that fuse in adulthood. Computed tomography of the Indian tail clubs reveals their internal structure, which shows incremental growth lines as well as other features whose origin and function remain unknown. The Indian and Chinese tail clubs share a similar temporal range (Early to Middle Jurassic) and similar morphologies, which raises the question of whether sauropod tail clubs evolved once, multiple times, or were gained and then lost within basally diverging members of Sauropoda. We describe four new characters to reflect the morphological constituents of sauropod tail clubs known to date.

Visualisation of dental anatomy in CBCT scans (Part 2).

To the trained eye, every tooth is different. An in-depth understanding of dental anatomy in cross-sectional images is a fundamental basic skill required when interpreting cone beam computed tomography (CBCT) scans. The conventional orthogonal planes of axial, coronal, and sagittal are not always the best planes in which to assess teeth because every tooth is at a slightly different angle to all these planes. In this chapter, the author demonstrates the characteristic anatomy of upper and lower incisors, canines, premolars, and molars in longitudinal and transverse sections, using carefully uprighted images. Some of these teeth are also shown in transverse section at various levels in the crown and root. The chronology of permanent teeth is shown. Developing teeth are discussed and incremental growth lines are mentioned.The author describes three well-known dental notation systems (Palmer, FDI, hybrid).There are four videos accompanying this chapter, including one fascinating video showing a scroll-through of all the cross-arch sections of a synthetic panoramic (curved multiplanar reconstruction) image that includes all the upper and lower teeth in a 16-year-old.

Visualisation of dental anatomy in CBCT scans: Part 1.

To the trained eye, every tooth is different. An in-depth understanding of dental anatomy in cross-sectional images is a fundamental basic skill required when interpreting cone beam computed tomography (CBCT) scans. The conventional orthogonal planes of axial, coronal, and sagittal are not always the best planes in which to assess teeth because every tooth is at a slightly different angle to all these planes. In this chapter, the author demonstrates the characteristic anatomy of upper and lower incisors, canines, premolars, and molars in longitudinal and transverse sections, using carefully uprighted images. Some of these teeth are also shown in transverse section at various levels in the crown and root. The chronology of permanent teeth is shown. Developing teeth are discussed and incremental growth lines are mentioned.The author describes three well-known dental notation systems (Palmer, FDI, hybrid).There are four videos accompanying this chapter, including one fascinating video showing a scroll-through of all the cross-arch sections of a synthetic panoramic (curved multiplanar reconstruction) image that includes all the upper and lower teeth in a 16-year-old.

A potential role of p75NTR in the regulation of circadian rhythm and incremental growth lines during tooth development.

Objective: Tooth morphogenesis and the formation of hard tissues have been reported to be closely related to circadian rhythms. This study investigates the spatiotemporal expression and relationship of p75NTR with core clock genes, mineralization-related or odontogenesis-related genes, and aims to derive the potential role of p75NTR in regulating circadian rhythm and incrementality growth line formation during tooth development. Materials and methods: The dynamic morphology of the rat dental germ was observed at seven stages (E14.5 d, E16.5 d, E18.5 d, P.N. 4 d, P.N. 7 d, P.N. 10 d, and P.N. 15 d). Next, the expressions of p75NTR and other target factors were traced. The ectomesenchymal stem cells (EMSCs) were isolated from the E18.5d rat dental germs and synchronized using 50% of fetal bovine serum. Then, they were cultured in light/light (L.L.), dark/dark (D.D.), and light/dark (L.D.) conditions for 48 h. The total RNA was collected every 4 h, and the circadian rhythm dynamics of target factors were observed. To reveal the mechanism further, p75NTR was down-regulated in p75NTR ExIII−/− mice and up-regulated in immortalized mouse dental apical papilla progenitor cells. The change tendencies of other target factors were also detected. Results: The clock genes Bmal1, Clock, Per1, and Per2 were all expressed in tooth germs before the formation of dental hard tissues and demonstrated a regular oscillating expression pattern in EMSCs from dental germs. Their expression was affected by the L.D. stimulus, and most of them were promoted by D.D. conditions. p75NTR presented a similar expression pattern and a positive or negative relationship with most clock genes, mineralization-related and odontogenesis-related factors, such as brain and muscle ARNT-like protein-1 (Bmal1), runt-related transcription factor 2 (Runx2), alkaline phosphatase (ALP), MSH-like 1 (MSX1), dentin matrix acidic phosphoprotein 1 (Dmp1), and dentin sialophosphoprotein (Dspp). Moreover, the arrangement, morphology, and even boundary in pre-odontoblast/pre-ameloblast layers were disordered in the p75NTR ExIII−/− mice. Conclusion: Circadian rhythm was found to affect tooth development. p75NTR might play a crucial role in regulating clock genes in the mineralization and formation of the dental hard tissues. p75NTR is actively involved in the odontoblast-ameloblast junction and cell polarity establishment during tooth morphogenesis.

Oxygen isotopes from the teeth of Cretaceous marine lizards reveal their migration and consumption of freshwater in the Western Interior Seaway, North America

Mosasaurs were widespread predators of the vast Cretaceous seas, and it is debated whether these extinct marine reptiles migrated to coastal environments to feed or reproduce. Here we investigate the potential for migration of mosasaurs through novel high-resolution sclerochronology that samples incremental growth lines in fossil mosasaur teeth and extracts oxygen isotopes from pristine enamel. Oxygen isotope trends of consecutive teeth are spliced to reconstruct one to seven month-long life histories of Platecarpus tympaniticus and Clidastes propython mosasaurs, respectively, collected from time-equivalent chalk deposits of the Western Interior Seaway and Mississippi Embayment of North America. The records of all individuals—two adults and one juvenile—are characterized by semi-regular depletions in oxygen isotope values, indicating travel from marine to freshwater coastal environments. Weekly to bi-weekly consumption of freshwater by two genera at diverse life stages implies that mosasaur osmoregulatory function was similar to their living sea snake relatives that drink freshwater periodically.

Incremental Growth Lines in Mouse Molar Dentin Represent 8-hr Ultradian Rhythm.

Rhythmic incremental growth lines occur in dental hard tissues of vertebrates, and dentinogenesis in rodent incisors is suggested to be controlled by the 24-hr circadian clock. Rodent incisors continue to grow throughout the animal’s life; however, similar to human teeth, rodent molars stop growing after crown formation. This similarity suggests that the mouse molar is an excellent model to understand the molecular mechanisms underlying growth of human teeth. However, not much is known about the rhythmic dentinogenesis in mouse molars. Here, we investigated the incremental growth lines in mouse molar dentin using tetracycline as the growth marker. The incremental growth lines were observed to be generated at approximately 8-hr intervals in wild-type mice housed under 12:12 hr light-dark conditions. Moreover, the 8-hr rhythmic increments persisted in the wild-type and Bmal1−/− mice housed in constant darkness, where Bmal1−/− mice become behaviorally arrhythmic. These results revealed that the dentinogenesis in mouse molars underlie the ultradian rhythms with around 8-hr periodicity. Further, the circadian clock does not seem to be involved in this process, providing new insight into the mechanisms involved in the tooth growth.

Patterns of lateral enamel growth in Homo naledi as assessed through perikymata distribution and number

Perikymata, incremental growth lines visible on tooth enamel surfaces, differ in their distribution and number among hominin species, although with overlapping patterns. This study asks: (1) How does the distribution of perikymata along the lateral enamel surface of Homo naledi anterior teeth compare to that of other hominins? (2) When both perikymata distribution and number are analyzed together, how distinct is H. naledi from other hominins? A total of 19 permanent anterior teeth (incisors and canines) of H. naledi were compared, by tooth type, to permanent anterior teeth of other hominins: Australopithecus afarensis, Australopithecus africanus, Paranthropus robustus, Paranthropus boisei, Homo ergaster/Homo erectus, other early Homo, Neandertals, and modern humans, with varying sample sizes. Repeated measures analyses of the percentage of perikymata per decile of reconstructed crown height yielded several statistically significant differences between H. naledi and other hominins. Canonical variates analysis of percentage of perikymata in the cervical half of the crown together with perikymata number revealed that, in 8 of 19 cases, H. naledi teeth were significantly unlikely to be classified as other hominins, while exhibiting least difference from modern humans (especially southern Africans). In a cross-validated analysis, 68% of the H. naledi teeth were classified as such, while 32% were classified as modern human (most often southern African). Of 313 comparative teeth use for this analysis, only 1.9% were classified as H. naledi. What tends to differentiate H. naledi anterior tooth crowns from those of most other hominins, including some modern humans, is strongly skewed perikymata distributions combined with perikymata numbers that fall in the middle to lower ranges of hominin values. H. naledi therefore tends toward a particular combination of these features that is less often seen in other hominins. Implications of these data for the growth and development of H. naledi anterior teeth are considered.

Incremental growth of therizinosaurian dental tissues: implications for dietary transitions in Theropoda.

Previous investigations document functional and phylogenetic signals in the histology of dinosaur teeth. In particular, incremental lines in dentin have been used to determine tooth growth and replacement rates in several dinosaurian clades. However, to date, few studies have investigated the dental microstructure of theropods in the omnivory/herbivory spectrum. Here we examine dental histology of Therizinosauria, a clade of large-bodied theropods bearing significant morphological evidence for herbivory, by examining the teeth of the early-diverging therizinosaurian Falcarius utahensis, and an isolated tooth referred to Suzhousaurus megatherioides, a highly specialized large-bodied representative. Despite attaining some of the largest body masses among maniraptoran theropod dinosaurs, therizinosaurian teeth are diminutive, measuring no more than 0.90 cm in crown height (CH) and 0.38 cm in crown base length (CBL). Comparisons with other theropods and non-theropodan herbivorous dinosaurs reveals that when controlling for estimated body mass, crown volume in therizinosaurians plots most closely with dinosaurs of similar dietary strategy as opposed to phylogenetic heritage. Analysis of incremental growth lines in dentin, observed in thin sections of therizinosaurian teeth, demonstrates that tooth growth rates fall within the range of other archosaurs, conforming to hypothesized physiological limitations on the production of dental tissues. Despite dietary differences between therizinosaurians and hypercarnivorous theropods, the types of enamel crystallites present and their spatial distribution—i.e., the schmelzmuster of both taxa—is limited to parallel enamel crystallites, the simplest form of enamel and the plesiomorphic condition for Theropoda. This finding supports previous hypotheses that dental microstructure is strongly influenced by phylogeny, yet equally supports suggestions of reduced reliance on oral processing in omnivorous/herbivorous theropods rather than the microstructural specializations to diet exhibited by non-theropodan herbivorous dinosaurs. Finally, although our sample is limited, we document a significant reduction in the rate of enamel apposition contrasted with increased relative enamel thickness between early and later diverging therizinosaurians that coincides with anatomical evidence for increased specializations to herbivory in the clade.

Postcanine microstructure in Cricodon metabolus, a Middle Triassic gomphodont cynodont from south‐eastern Africa

AbstractCricodon metabolus is a trirachodontid cynodont from the Anisian (Middle Triassic) of eastern and southern Africa. It has labiolingually expanded (gomphodont) postcanines but also a sectorial tooth in the last postcanine locus. In this paper, we examine the crown microstructure of isolated sectorial and gomphodont postcanines belonging to the holotype specimen of this taxon using scanning electron microscopy. The enamel of both teeth is prismless and composed of discontinuous columnar divergence units, supporting the consistent presence of synapsid columnar enamel in cynognathians. Abundant tubules and numerous irregularly spaced incremental lines are also visible in the enamel and dentine layers in each tooth. This study reveals that the enamel thickness varies along the tooth row in Cricodon as the enamel layer of the gomphodont postcanines is 11.5 times thicker than that of the sectorial crown. It is likely that this difference reflects occlusal stresses and fewer replacements in gomphodont postcanines relative to sectorial teeth. Approximately 100 incremental growth lines of von Ebner are present in the dentine layer, indicating that the deposition of the dentine by odontoblasts occurred for three months before the animal's death.

Circadian Rhythm Regulates Development of Enamel in Mouse Mandibular First Molar.

Rhythmic incremental growth lines and the presence of melatonin receptors were discovered in tooth enamel, suggesting possible role of circadian rhythm. We therefore hypothesized that circadian rhythm may regulate enamel formation through melatonin receptors. To test this hypothesis, we examined expression of melatonin receptors (MTs) and amelogenin (AMELX), a maker of enamel formation, during tooth germ development in mouse. Using qRT-PCR and immunocytochemistry, we found that mRNA and protein levels of both MTs and AMELX in normal mandibular first molar tooth germs increased gradually after birth, peaked at 3 or 4 day postnatal, and then decreased. Expression of MTs and AMELX by immunocytochemistry was significantly delayed in neonatal mice raised in all-dark or all-light environment as well as the enamel development. Furthermore, development of tooth enamel was also delayed showing significant immature histology in those animals, especially for newborn mice raised in all daylight condition. Interestingly, disruption in circadian rhythm in pregnant mice also resulted in delayed enamel development in their babies. Treatment with melatonin receptor antagonist 4P-PDOT in pregnant mice caused underexpression of MTs and AMELX associated with long-lasting deficiency in baby enamel tissue. Electromicroscopic evidence demonstrated increased necrosis and poor enamel mineralization in ameloblasts. The above results suggest that circadian rhythm is important for normal enamel development at both pre- and postnatal stages. Melatonin receptors were partly responsible for the regulation.

Dental histology of mosasaurs and a marine crocodylian from the Campanian (Upper Cretaceous) of southern Sweden: incremental growth lines and dentine formation rates

AbstractMosasaurs are an extinct group of secondarily adapted aquatic lizards that became the dominant marine tetrapods in the Late Cretaceous oceans. They continuously shed and replaced their teeth in order to maintain a functional dentition at all times; however, the process of tooth development in mosasaurs is still incompletely known. Based on incremental line width measurements and growth line counts, we assess dentine formation rates in three mosasaur taxa (Dollosaurus, cf.PlatecarpusandTylosaurus) and one genus of marine crocodylian (Aigialosuchus), all from the lower Campanian (Upper Cretaceous) of southernmost Sweden. Two sets of periodic dentinal markings characterized by concentric, alternating opaque and transparent laminae are recognized: one set comprising thin bands situated 6–34 μm apart (depending on taxon), which is superimposed onto a second set of coarser bands where spaces vary between 102 and 275 μm. Assuming that the finer striations represent daily increments (i.e. lines of von Ebner), it is estimated that the deposition of dentine at the sectioned level of the tooth-crowns took 342 (cf.Platecarpus), 426 (Dollosaurus), 487 (Tylosaurus) and 259 (Aigialosuchus) days, respectively. The coarser bands contain between 11 and 13 thin striations each, and are thus considered to be homologous to similar periodic dentinal markings in extant vertebrates, i.e. Andresen lines. Prolonged tooth development times in large-toothed taxa, such asTylosaurus, presumably increased the risk of long-term incapacity to capture prey after dental trauma, an evolutionary trade-off which may have been compensated for by allometric modifications of the teeth.

Reconstructing skeletal fiber arrangement and growth mode in the coral <i>Porites lutea</i> (Cnidaria, Scleractinia): a confocal Raman microscopy study

Abstract. Confocal Raman microscopy (CRM) mapping was used to investigate the microstructural arrangement and organic matrix distribution within the skeleton of the coral Porites lutea. Relative changes in the crystallographic orientation of crystals within the fibrous fan-system could be mapped, without the need to prepare thin sections, as required if this information is obtained by polarized light microscopy. Simultaneously, incremental growth lines can be visualized without the necessity of etching and hence alteration of sample surface. Using these methods two types of growth lines could be identified: one corresponds to the well-known incremental growth layers, whereas the second type of growth lines resemble denticle finger-like structures (most likely traces of former spines or skeletal surfaces). We hypothesize that these lines represent the outer skeletal surface before another growth cycle of elongation, infilling and thickening of skeletal areas continues. We show that CRM mapping with high spatial resolution can significantly improve our understanding of the micro-structural arrangement and growth patterns in coral skeletons.

Totoralia, a new conical-shaped mollusk from the middle Cambrian of western Argentina

The new genus Totoralia from the late middle Cambrian of El Totoral (Mendoza Province, western Argentina) is described herein. It is a delicate, high, bilaterally symmetrical cone with a sub-central apex and five to seven prominent comarginal corrugations. In addition, its surface shows numerous fine comarginal lines, as well as thin, closely spaced radial lirae. Totoralia gen. nov., in most respects, resembles the Cambrian helcionellids Scenella BILLINGS and Palaeacmaea HALL and Whitfield. Although Scenella has been considered as a chondrophorine cnidarian by some authors in the past, now the predominant view is that it is a mollusk. Likewise, several aspects of Totoralia gen. nov. morphology indicate closer affinities with mollusks. The specimens studied constitute elevated cones that are rather consistent in height, implying that they were not flexible structures like those of the chondrophorines. The presence of a short concave slope immediately in front of the apex can also be interpreted as a mollusk feature. In addition, the numerous comarginal lines of the cone are uniform in prominence and constant in spacing, and are only represented on the dorsal surface of the shell; thus, they are most similar to the incremental growth lines of shells of mollusks. The morphology of Totoralia gen. nov. is regarded as primitive in the Helcionelloida because the ancestor of the class is likely to have had a minute, untorted limpet-shaped shell. Although the new genus herein described seems to be endemic to Argentina, the Cambrian occurrences of related scenellid genera suggest affinities with Laurentia.

Systematics and Taxonomy of Great Striped-Faced Bats of the GenusVampyrodesThomas, 1900 (Chiroptera: Phyllostomidae)

The Neotropical bat genus Vampyrodes (Chiroptera: Phyllostomidae: Stenodermatinae) is widely distributed from southern Mexico to southeastern Brazil. Long thought to be monotypic, V. caraccioli Thomas, 1889, was recognized by previous authors as including two subspecies with the nominate form inhabiting South America south and east of the Andes, and another subspecies, V. c. major Allen, 1908, occurring west and north of the Andes. Reexamination of these forms using molecular and morphological methods supports recognition of these lineages as distinct at the species level. We here provide amended descriptions and diagnoses for these taxa. We also report for the first time an example of perikymata (incremental growth lines that appear on the surface of dental enamel as a series of grooves) in Chiroptera. Presence of distinct perikymata is a synapomorphy of the genus Vampyrodes.

Microstructure of enamel.

Enamel is a composite material consisting of mineral and organic phases. The properties of the mineral phase are modulated dramatically by its division into microscopic crystals, cemented together by the organic matrix protein polymer. A good concept of the 3D orientations of the crystals derives from visualizing their growth perpendicular to the surface in which they develop, which is pitted by the secretory poles of the ameloblasts. The arrangement of the crystals is the cause of the discontinuities, known as the prism boundaries or junctions, in the otherwise continuous structure. These locations acquire a more concentrated organic matrix during maturation, and they are both crack stoppers and crack propagation tracks in the adult tissue. Any tendency of prisms to cleave may be reduced by their varicosities, which reflect daily variations in the rate of production; their cross-sectional shape; the non-parallelism of adjacent groups, which develops through translocation of groups of cells across the surface during development; and the support of any one microscopic tissue element by other tissue, including dentine, placed to resist an applied load. Incremental growth lines are preferential cleavage planes within the enamel. Failure patterns of enamel in normal and abnormal use can be explained by these parameters, with additional consideration of functional variation and fatigue.

Developmental processes and canine dimorphism in primate evolution

Understanding the evolutionary history of canine sexual dimorphism is important for interpreting the developmental biology, socioecology and phylogenetic position of primates. All current evidence for extant primates indicates that canine dimorphism is achieved through bimaturism rather than via differences in rates of crown formation time. Using incremental growth lines, we charted the ontogeny of canine formation within species of Eocene Cantius, the earliest known canine-dimorphic primate, to test whether canine dimorphism via bimaturism was developmentally canalized early in primate evolution. Our results show that canine dimorphism in Cantius is achieved primarily through different rates of crown formation in males and females, not bimaturism. This is the first demonstration of rate differences resulting in canine dimorphism in any primate and therefore suggests that canine dimorphism is not developmentally homologous across Primates. The most likely interpretation is that canine dimorphism has been selected for at least twice during the course of primate evolution. The power of this approach is its ability to identify underlying developmental processes behind patterns of morphological similarity, even in long-extinct primate species.

Growth increments in Gomphotherium tusks and implications for late Miocene climate change in North America

Changes in mammalian faunas in North America during the late Miocene are thought to have been caused by the replacement of woodland habitats with grassland or steppe. The proposed cause of this habitat shift is the transition from the relatively low-seasonality early Miocene climate to a more highly seasonal climate regime by the end of the Miocene. Tusks, which are highly modified incisor teeth, of late Miocene Gomphotherium (Mammalia, Proboscidea) were sectioned to document the nature of tusk growth in this genus and to test for patterns of seasonal growth. Both the dentin and enamel of Gomphotherium tusks preserve incremental growth lines. Dentin has increments on three scales, inferred to represent annual (first-order), weekly (second-order), and daily (third-order) periodicities. Luminance and second-order increment thickness profiles were measured on transverse thin sections of tusk dentin viewed at low magnification, and the data were examined with bivariate plots and autocorrelation. Autocorrelograms of luminance data support the consistent identification and measurement of second-order increments within and among the tusks sampled. Profiles of second-order increment thickness in three tusks from the Barstovian North America Land Mammal Age (NALMA) show no indication of seasonal patterns of growth. One tusk from the late Clarendonian and one from the early Hemphillian NALMA have patterns of growth consistent with an increase in seasonality during the late Miocene, an interpretation supported by autocorrelation of the increment thickness data from these tusks. The growth patterns are consistent with the hypothesized changes in North American climate during the late Miocene and are suggestive of an increase in aridity and development of a wet season. Tests of this hypothesis are suggested.

On thick and thin enamel in hominoids

AbstractMartin (1983, 1985) reviewed the significance of enamel thickness in hominoid evolution. He studied cut faces of hominoid teeth using the scanning electron microscope and related enamel prism packing patterns to both enamel formation rates and enamel thickness, although he did not present primary data on formation rates, which he summarised as being either “fast” or “slow.” Martin concluded that thick enamel formed at a fast rate represented the ancestral condition in the human and great ape clade. Thin enamel in African apes reflected a secondary reduction in secretion rates, with outer enamel being formed at a slow rate. The present study on ground sections of great ape and human teeth, using polarised light microscopy, was designed to measure the spacing between incremental growth lines in enamel, including striae of Retzius and prism cross striations, to determine rates of enamel formation in hominoids. Measurements on stria spacing showed that striae generally diverged as they passed outwards through enamel in all taxa. Cross‐striation spacings also increased from inner to outer enamel. Secretion rates did not fall into two exclusive categories but varied, giving a spectrum of values generally increasing from within outwards at any one crown level and reducing in cervical enamel. There was no evidence for a reduction in enamel formation rates in outer enamel among African apes. These findings cast doubt on the proposition that the common ancestor of great apes and man had thick enamel formed at a fast rate. It is possible that thin enamel was the primitive condition, in which case thick enamel in humans and in Sivapithecus is derived, suggesting that thick enamel on low cusped teeth evolved on more than one occasion.

Histological study on the chronology of the developing dentition in gorilla and orangutan

AbstractThe single previous study on tooth development in great apes (Dean and Wood: Folia Primatol. (Basel) 36:111–127, 1981) is of limited value because it is based on cross‐sectional radiographic data. This study considers problems in defining stages of tooth development in radiographs of developing ape dentitions and provides data on tooth chronology in Pongo pygmaeus and Gorilla gorilla by using histological methods of analysis. Crown formation times were estimated in individual teeth, and an overall chronology of dental development was found by registering teeth forming at the same time by using incremental growth lines. The earlier radiographic study correctly identified the molar and second premolar chronology and sequence in great apes, but significantly underestimated crown formation times in incisors, first premolars, and canine teeth in particular. Ape anterior tooth crowns take longer to form than the equivalent human teeth, but the overall dental developmental period in great apes is substantially shorter than in humans. Gorilla root extension rates appear to be fast, up to approximately 13 μm/day. This rapid root growth, associated with early tooth eruption, appears to be the developmental basis for the observed differences in timing between developing dentitions in great apes and humans.

Age Determination and Occurrence of Incremental Growth Lines in the Dental Cementum of the Common Vampire Bat (Desmodus rotundus)

Age Determination and Occurrence of Incremental Growth Lines in the Dental Cementum of the Common Vampire Bat (Desmodus rotundus)