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2021 ◽  
Vol 71 ◽  
pp. 425-437
Author(s):  
L. Lee Grismer

Abstract It is hypothesized that shape differences between the closely related sandstone night lizard (Xantusia gracilis) and the granite night lizard (X. henshawi) may be correlated with structual differences in their respective microhabitats. Multivariate and univariate analyses of 22 morphometric characters taken from the head, body, and limbs of both saxicolus specialists recovered statistically significant differences between them with X. gracilis having a wider head, longer snout, larger eyes, wider sternum, higher and wider pelvis, thinner limbs, longer forearms and thighs, and longer hind limbs. Many of these same proportional differences have been reported among very closely related saxicolus species in other lizard families (i.e. Eublepharidae, Gekkonidae, Phrynosomatidae) that also live on different rocky substrates. This supports the inference that morphometric differences between X. gracilis and X. henshawi are ecomorphological adaptations for navigating the substantially different substrates of their respective microhabitats. Xantusia gracilis is restricted to a loose, heterogeneous, sandstone microhabitat composed of large boulders, small rocks, and cliff faces where cracks, crevices, holes, and exfoliations are used as retreats versus the compact, more homogeneous, granite boulder microhabitat of X. henshawi where narrow spaces beneath exfoliations and cap-rocks are the preferred retreats.


Zootaxa ◽  
2021 ◽  
Vol 4969 (2) ◽  
pp. 351-366
Author(s):  
ISHAN AGARWAL ◽  
TEJAS THACKERAY ◽  
AKSHAY KHANDEKAR

We describe a new species of the Cnemaspis bangara clade from a rocky hillock near Kugai Periya Mariamman Temple, Krishnagiri fort, Krishnagiri District of Tamil Nadu, India. Cnemaspis krishnagiriensis sp. nov. can be diagnosed from all other peninsular Indian congeners by its medium body size (maximum SVL 40 mm), heterogeneous dorsal pholidosis, spine-like tubercles absent on flanks; presence of four femoral pores on each thigh separated on either side by nine or 10 poreless scales from three continuous precloacal pores in males; tail with enlarged, strongly keeled, conical tubercles forming four whorls on anterior portion, six tubercles in first whorl, four tubercles in second to fourth whorls, enlarged tubercles restricted to only paravertebral region on rest of the tail; median row of sub-caudals smooth and distinctly enlarged, and a unique colour pattern. The new species can be diagnosed from members of C. bangara clade by the number of dorsal tubercles rows at mid-body, the number of enlarged tubercles in paravertebral rows, the number of ventral scales across belly at mid-body, the number longitudinal ventral scales from mental to cloaca, the number of femoral and precloacal pores and poreless scales separating these series, and subtle colour pattern differences; besides 9.2–17.6 % uncorrected ND2 sequence divergence. Cnemaspis krishnagiriensis sp. nov. is the fourth member of the recently described bangara clade and is the first that is known to be distributed <900 m asl.. The discovery of yet another endemic species of Cnemaspis from lower elevations of the Mysore Plateau once again highlights the need of dedicated systematic sampling to uncover the true diversity of Cnemaspis. We also address a nomenclatural issue related to the recently described Cnemaspis stellapulvis Khandekar, Thackeray & Agarwal. 


2021 ◽  
Author(s):  
Masahiro Chigira ◽  
Yasuto Hirata

&lt;p&gt;Typical cooling joints of granite have been believed to be orthogonal, and characteristic topography of granitic rocks like tors and boulder fields are interpreted in combination with the cooling joints and weathering. However, most of the previous studies were performed by the observation on the ground, and the 3D observation of cooling joints and the topographic features was not sufficient. We observed tors and boulder fields of granitic rocks using UAV and 3D modelling and found that columnar joints are typical for the granite that forms tors and that boulder fields are the accumulations of rock columns as well as boulders made by the spheroidal weathering of rock columns. Tors we observed were Mt. Kinabalu of Borneo, Mt. Mizugaki, Mt. Jizo, Mt. Gozaisho, Mt. Konze and 5 other locations in Japan. We observed that tors consist of polygonal rock columns with undulating joints, more irregularly shaped than the columnar joints of volcanic rocks. The cross-sectional areas of rock columns varied from 1 to 130 m^2, much larger than typical rock columns of volcanic rocks. The rock columns of granite are typically polygonal dipyramids, of which shapes may be dependent on the cooling history of granite. Boulder fields we observed was the Kui boulder fields in Hiroshima. We found that the boulder field is the accumulation of prismatic rock columns as well as rounded rock boulders. The prismatic rock columns had basal cross-sectional areas of 0.8 m^2 on average. The rock columns had chamfering cracks at corners, which are assumed to be made during cooling and to form preliminary outlines of core stones. Core stones had surface crusts or rindlets, which exfoliate and leave more rounded core stones.&lt;/p&gt;&lt;p&gt;&amp;#160;&amp;#160;Rainstorm-induced landslides of weathered granite reflect weathering styles of granite: Landslides that occurred recently in Japan had three types, landslides of loosened layers of decomposed granite (or micro-sheeted granite), landslides of core-stone bearing materials, and landslides of saprolite. Landslides with core-stones were particularly destructive because of their inertia. Potential sites of such landslides could be predicted using columnar joints in fresh rocks as a clue.&lt;/p&gt;


2019 ◽  
Vol 1 (2) ◽  
pp. 114-117
Author(s):  
Mohd Firdaus Md Dan

The aim of this research is to investigate the effect of spheroidal weathering on the physico-mechanical properties of in situ granite boulder in tropical environment. This research was conducted to gain more understanding due to lack of study related to this topic especially on tropical boulder in completely weathered zone. A number of 34 in situ granite boulders that naturally formed in completely weathered zone were selected and investigated from two quarries located in Southern Johor, Malaysia. Classification of weathering grade was conducted on the material surrounding boulder based on discolouration, degree of friability and texture characteristics as suggested by ISRM(1). The colour of the weathered material were classified based on Rock Colour Chart (2). Petrographic analysis and scanning electron microscopy (SEM) were carried out to analyze the mineralogical and microstructure alterations, respectively due to weathering effect. The changes of physico-mechanical properties at the surrounding of boulder due to weathering were also analyzed including dry density, porosity, point load strength, uniaxial compressive strength and permeability. The dry density and porosity were conducted based on ASTM (3) and Brown (4), respectively. The point load uniaxial compressive strength were carried out according to ISRM (1) while permeability test was undertaken based on Head (5). The tropical granite boulder possessing rindlets with significant different of colours, degree of friability and texture. This differences were classified into four primary zones: corestone (C), inner rindlets (IR), outer rindlets (OR), and saprolites (S) with weathering grade of II, III/IV, IV/V and V, respectively. Due to spheroidal weathering, three to six concentric sheets of rindlets with whitish grey to light brown colour were formed at the surrounding of corestone's boulder. Each sheets of rindlets has 2.0 cm to 3.0 cm thick with total thickness up to 80 cm. The microcracks aperture of IR and OR is ranging from 150 to 200 µm and 200 µm to 1 mm, respectively. Analysis revealed that the higher the weathering grade, the higher and wider the fracture opening formed in the rindlets up to 2 mm width. Analysis exibited that the increase of weathering grade from Grade II to IV along C to S were significantly reduced the plagioclase, K-feldspar, and biotite with reduction of 74%, 74.2% and 87.5%, respectively. The alteration of minerals and microstructure due to the weathering were significantly reduced the dry density, point load strength, uniaxial compressive strength and permeability with 32%, 99.5%, 98.6% and 84.8%, respectively.The reaction of spheroidal weathering is significantly affecting the physico-mechanical properties of the tropical granite boulders by alteration of its minerals and microstructure characteristics at the surrounding of the boulder.


2019 ◽  
pp. 61-91
Author(s):  
José Manuel Afonso

There is no point in rushing because, in fact, people are going nowhere in particular. No matter how arduous the observation, in a slow and difficult sequence, people are always in the same place: in the countryside. There, people were yesterday and will be tomorrow. The landscape is a singularity with no limits: each tree, each granite boulder, each course presents infinite perspectives indistinguishable from each other. Sustainable landscape will be a mandatory topic in the twenty-first century and will influence the interventions in open spaces. These new paradigms will allow a healthier environment, where the relation of architecture and environmental comfort is present. In this sense, the chapter addresses aspects of the environment in its relationship with living culture; studies construction techniques with a lower environmental impact; and develops adaptive strategies of “sustainable project” for ordering and appropriation of habitable space according to the principles of cultural, economic, and environmental preservation.


Author(s):  
José Manuel Afonso

There is no point in rushing because, in fact, people are going nowhere in particular. No matter how arduous the observation, in a slow and difficult sequence, people are always in the same place: in the countryside. There, people were yesterday and will be tomorrow. The landscape is a singularity with no limits: each tree, each granite boulder, each course presents infinite perspectives indistinguishable from each other. Sustainable landscape will be a mandatory topic in the twenty-first century and will influence the interventions in open spaces. These new paradigms will allow a healthier environment, where the relation of architecture and environmental comfort is present. In this sense, the chapter addresses aspects of the environment in its relationship with living culture; studies construction techniques with a lower environmental impact; and develops adaptative strategies of “sustainable project” for ordering and appropriation of habitable space according to the principles of cultural, economic, and environmental preservation.


Zootaxa ◽  
2017 ◽  
Vol 4300 (4) ◽  
pp. 486 ◽  
Author(s):  
L. LEE GRISMER ◽  
JESSE L. GRISMER

A re-evaluation of the phylogenetic relationships of the four species of the monophyletic Cyrtodactylus conodorensis group using the mitochondrial gene ND2 with Bayesian and Maximum Likelihood analyses provides strong statistical support for the recovery the cave-adapted ecomorphs C. eisenmanae and C. grismeri as the sister lineage to the scansorial forest-adapted ecomorphs C. condorensis and C. leegrismeri. This phylogeny provides the context in which these ecomorphs are morphologically characterized. The majority of newly described species within Cyrtodactylus have come from karst habitats and granite boulder cave-like microhabitats. Although some authors have commented on subtle to notable differences in the morphology and color pattern associated with species from these habitats, none have explicitly presented data necessary to characterize this putative departure from a more generalized, scansorial morphology. To this end, the closely related species of the condorensis group are used to provide a suggested protocol to recover and delimit characters adaptive to a restrictive lifestyle of climbing on flat, rocky substrates in low levels of illumination. Understanding the phylogenetic context in which a morphological shift from a general scansorial species to a rock-adapted species relative to the historical evolution of its environment has conservation and management implications. This is particularly important given that a number of the newly described karst-adapted species from throughout Southeast Asia are threatened with extension because of the ongoing quarrying activities of their habitat. 


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