scholarly journals Postcranial elements of small mammals as indicators of locomotion and habitat

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9634
Author(s):  
Christine M. Janis ◽  
Alberto Martín-Serra

Many studies have shown a correlation between postcranial anatomy and locomotor behavior in mammals, but the postcrania of small mammals (<5 kg) is often considered to be uninformative of their mode of locomotion due to their more generalized overall anatomy. Such small body size was true of all mammals during the Mesozoic. Anatomical correlates of locomotor behavior are easier to determine in larger mammals, but useful information can be obtained from the smaller ones. Limb bone proportions (e.g., brachial index) can be useful locomotor indicators; but complete skeletons, or even complete long bones, are rare for Mesozoic mammals, although isolated articular surfaces are often preserved. Here we examine the correlation of the morphology of long bone joint anatomy (specifically articular surfaces) and locomotor behavior in extant small mammals and demonstrate that such anatomy may be useful for determining the locomotor mode of Mesozoic mammals, at least for the therian mammals.

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Jordi Estefa ◽  
Paul Tafforeau ◽  
Alice M Clement ◽  
Jozef Klembara ◽  
Grzegorz Niedźwiedzki ◽  
...  

The production of blood cells (haematopoiesis) occurs in the limb bones of most tetrapods but is absent in the fin bones of ray-finned fish. When did long bones start producing blood cells? Recent hypotheses suggested that haematopoiesis migrated into long bones prior to the water-to-land transition and protected newly-produced blood cells from harsher environmental conditions. However, little fossil evidence to support these hypotheses has been provided so far. Observations of the humeral microarchitecture of stem-tetrapods, batrachians, and amniotes were performed using classical sectioning and three-dimensional synchrotron virtual histology. They show that Permian tetrapods seem to be among the first to exhibit a centralised marrow organisation, which allows haematopoiesis as in extant amniotes. Not only does our study demonstrate that long-bone haematopoiesis was probably not an exaptation to the water-to-land transition but it sheds light on the early evolution of limb-bone development and the sequence of bone-marrow functional acquisitions.


Development ◽  
1961 ◽  
Vol 9 (3) ◽  
pp. 534-555
Author(s):  
Kirstie Lawson

The maturation of the cartilage of embryonic chick long-bone rudiments growing in tissue culture is accelerated by addition of the thyroid hormones, thyroxine and triiodothyronine, but the growth in length of different long bones is not uniformly affected (Fell & Mellanby, 1955, 1956). Thus the growth of the hormone-treated tibia is less than that of a normal tibia, while the effect of thyroid hormone on the radius is to increase its growth. This differential response is not determined either by the stage of development at which the limb-bone rudiments are exposed to hormone, or by the size of the explant (Lawson, 1961). Investigations to determine whether the differential response of limb-bone rudiments to triiodothyronine (T3) is due to differences in the growth rates of different bones are described in this paper. The work was divided into three parts.


Zootaxa ◽  
2006 ◽  
Vol 1361 (1) ◽  
pp. 33 ◽  
Author(s):  
JULIO C. MONGUILLOT ◽  
MARIO R. CABRERA ◽  
JUAN C. ACOSTA ◽  
JOSE VILLAVICENCIO

A new species of Iguanidae Liolaemini lizard from the San Guillermo National Park in western Argentina, is described. The new species is a member of the Liolaemus darwinii complex within the monophyletic boulengeri species group. It is distinguished by its small body size, relatively long tail, low number of scales around midbody, dorsal scales moderately keeled, precloacal pores only in male, bulged patch of enlarged scales on the proximal posterior surface of the thigh in both sexes, dorsal pattern lacking of light vertebral or dorsolateral stripes, antehumeral fold without black pigment in female but greyish in male, a prescapular dark dot dorsal to antehumeral fold in both sexes, and postscapular spot absent. The new species is terrestrial, living in habitats with gravel and sandy soil in an Andean Monte landscape with sparse vegetation, above 2270 meters of altitude.


Zootaxa ◽  
2011 ◽  
Vol 2804 (1) ◽  
pp. 25 ◽  
Author(s):  
BRYAN L. STUART ◽  
JODI J. L. ROWLEY ◽  
DAO THI ANH TRAN ◽  
DUONG THI THUY LE ◽  
HUY DUC HOANG

We sampled two forms of Leptobrachium in syntopy at the type locality of L. pullum at upper elevations on the Langbian Plateau, southern Vietnam. The two forms differed in morphology (primarily in coloration), mitochondrial DNA, and male advertisement calls. One form closely agrees with the type series of L. pullum (but not to its original description due to error), and the other is described as new. Leptobrachium leucops sp. nov. is distinguished from its congeners by having small body size (males with SVL 38.8–45.2), the upper one-third to one-half of iris white, a blue scleral arc, a dark venter, and sexually active males without spines on the upper lip. Leptobrachium pullum and L. mouhoti, a recently described species from low-elevation slopes of the Langbian Plateau in eastern Cambodia, are morphologically divergent but genetically similar, warranting further investigation into geographic variation in the red-eyed Leptobrachium of southern Indochina.


1972 ◽  
Vol 127 (4) ◽  
pp. 715-720 ◽  
Author(s):  
Bryan P. Toole ◽  
Andrew H. Kang ◽  
Robert L. Trelstad ◽  
Jerome Gross

The different anatomical regions involved in osteogenesis in the chick long bone have been examined for heterogeneities in collagen structure that might relate to the mechanism of ossification. Experimentally induced lathyrism was employed to enhance collagen solubility, and vitamin D deficiency to allow accumulation of osteoid, the precursor of bone matrix. The extractable lathyritic collagens of the cartilaginous and osseous regions of growing long bones from rachitic and non-rachitic chicks were examined for α-chain type and amino acid composition. In both groups of animals the growth plate and cartilaginous regions of the epiphysis gave collagen molecules of the constitution [α1(II)]3, whereas the ossifying regions contained [α1(I)]2 α2. The degree of hydroxylation of the lysine moieties was increased by approximately 50% in the α1(I)-chain and α2-chain of rachitic bone collagen. Since uncalcified osteoid is greatly enriched in rachitic bone, it is concluded that the collagen of osteoid has the configuration [α1(I)]2 α2, similar to that of bone matrix, but has an elevated hydroxylysine content. The possible relationship of this difference to the mechanism of calcification is discussed.


1973 ◽  
Vol 39 (2) ◽  
pp. 255-261 ◽  
Author(s):  
A. Roberto Frisancho ◽  
Jorge Sanchez ◽  
Danilo Pallardel ◽  
Lizandro Yanez

1991 ◽  
Vol 124 (5) ◽  
pp. 602-607 ◽  
Author(s):  
Ben A. A. Scheven ◽  
Nicola J. Hamilton

Abstract. Longitudinal growth was studied using an in vitro model system of intact rat long bones. Metatarsal bones from 18- and 19-day-old rat fetuses, entirely (18 days) or mainly (19 days) composed of chondrocytes, showed a steady rate of growth and radiolabelled thymidine incorporation for at least 7 days in serum-free media. Addition of recombinant human insulin-like growth factor-I to the culture media resulted in a direct stimulation of the longitudinal growth. Recombinant human growth hormone was also able to stimulate bone growth, although this was generally accomplished after a time lag of more than 2 days. A monoclonal antibody to IGF-I abolished both the IGF-I and GH-stimulated growth. However, the antibody had no effect on the growth of the bone explants in control, serum-free medium. Unlike the fetal long bones, bones from 2-day-old neonatal rats were arrested in their growth after 1-2 days in vitro. The neonatal bones responded to IGF-I and GH in a similar fashion as the fetal bones. Thus in this study in vitro evidence of a direct effect of GH on long bone growth via stimulating local production of IGF by the growth plate chondrocytes is presented. Furthermore, endogenous growth factors, others than IGFs, appear to play a crucial role in the regulation of fetal long bone growth.


1986 ◽  
Vol 13 (4) ◽  
pp. 597 ◽  
Author(s):  
WJ Freeland ◽  
BLJ Delvinquier ◽  
B Bonnin

Cane toads from an urban population in Townsville, Qld, exhibit poor body condition and small body size, as do toads in populations around Townsville which have declined in numbers. The small body size and poor condition are associated with a high food intake and a low rate of parasitism. The results suggest that decline of rural populations is not a product of parasitism, or food and or water shortages related to unusually adverse seasonal conditions. Populations of cane toads around Townsville declined more than 3 years before this study.


2019 ◽  
Author(s):  
Holly Dupuis ◽  
Michael Andrew Pest ◽  
Ermina Hadzic ◽  
Thin Xuan Vo ◽  
Daniel B. Hardy ◽  
...  

AbstractLongitudinal bone growth occurs through endochondral ossification (EO), controlled by various signaling molecules. Retinoid X Receptor (RXR) is a nuclear receptor with important roles in cell death, development, and metabolism. However, little is known about its role in EO. In this study, the agonist SR11237 was used to evaluate RXR activation on EO.Rats given SR11237 from post-natal day 5 to 15 were harvested for micro-computed tomography scanning and histology. In parallel, newborn CD1 mouse tibiae were cultured with increasing concentrations of SR11237 for histological and whole mount evaluation.RXR agonist-treated rats were smaller than controls, and developed dysmorphia of the growth plate. Cells invading the calcified and dysmorphic growth plate appeared pre-hypertrophic in size and shape corresponding with P57 immunostaining. Additionally, SOX9 positive cells were found surrounding the calcified tissue. The epiphysis of SR11237 treated bones showed increased TRAP staining, and additional TUNEL staining at the osteo-chondral junction. MicroCT revealed morphological disorganization in the long bones of treated animals. Isolated mouse long bones treated with SR11237 grew significantly less than their DMSO controls.This study demonstrates that stimulation of the RXR receptor causes irregular ossification, premature closure of the growth plate, and disrupted long bone growth in rodent models.


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