A new rock dwelling Hemidactylus (Squamata: Gekkonidae) from Chhattisgarh, India

A distinct new species of gecko of the genus Hemidactylus is described from the Kanker district of Chhattisgarh State, east-central India. This large-sized (SVL average 81.33 +/- 13.40 to at least 98.0 mm) Hemidactylus is characterized by a dorsum with small granules, intermixed with 10-12 rows of irregularly arranged, slightly larger, rounded, weakly-keeled tubercles at midbody; 10-12 and 13-15 subdigital lamellae on the first and fourth digits, respectively, of both manus and pes; a single enlarged postcloacal tubercle on either side of the tail; 10-12 femoral pores on each thigh separated by 5-8 poreless scales; 12-14 supralabials and 10-12 infralabials.

A new rock dwelling Hemidactylus (Squamata: Gekkonidae) from Chhattisgarh, India

A distinct new species of gecko of the genus Hemidactylus is described from the Kanker district of Chhattisgarh State, east-central India. This large-sized (SVL average 81.33 +/- 13.40 to at least 98.0 mm) Hemidactylus is characterized by a dorsum with small granules, intermixed with 10-12 rows of irregularly arranged, slightly larger, rounded, weakly-keeled tubercles at midbody; 10-12 and 13-15 subdigital lamellae on the first and fourth digits, respectively, of both manus and pes; a single enlarged postcloacal tubercle on either side of the tail; 10-12 femoral pores on each thigh separated by 5-8 poreless scales; 12-14 supralabials and 10-12 infralabials.

Current kinematics and dynamics of Africa and the East African Rift System

Although the East African Rift System (EARS) is an archetype continental rift, the forces driving its evolution remain debated. Some contend buoyancy forces arising from gravitational potential energy (GPE) gradients within the lithosphere drive rifting. Others argue for a major role of the diverging mantle flow associated with the African Superplume. Here we quantify the forces driving present-day continental rifting in East Africa by (1) solving the depth averaged 3-D force balance equations for 3-D deviatoric stress associated with GPE, (2) inverting for a stress field boundary condition that we interpret as originating from large-scale mantle tractions, (3) calculating dynamic velocities due to lithospheric buoyancy forces, lateral viscosity variations, and velocity boundary conditions, and (4) calculating dynamic velocities that result from the stress response of horizontal mantle tractions acting on a viscous lithosphere in Africa and surroundings. We find deviatoric stress associated with lithospheric GPE gradients are similar to 8-20 MPa in EARS, and the minimum deviatoric stress resulting from basal shear is similar to 1.6 MPa along the EARS. Our dynamic velocity calculations confirm that a force contribution from GPE gradients alone is sufficient to drive Nubia-Somalia divergence and that additional forcing from horizontal mantle tractions overestimates surface kinematics. Stresses from GPE gradients appear sufficient to sustain present-day rifting in East Africa; however, they are lower than the vertically integrated strength of the lithosphere along most of the EARS. This indicates additional processes are required to initiate rupture of continental lithosphere, but once it is initiated, lithospheric buoyancy forces are enough to maintain rifting.

Impact of African orography and the Indian summer monsoon on the low-level Somali jet

The low-level jet (LLJ) over the Indian region, which is most prominent during the monsoon (June-September) season, has been studied with a general circulation model (GCM). The role of African orography in modulating this jet is the focus of this article. The presence o African orography intensifies the cross-equatorial flow. Contrary to previous modelling Studies we find that cross-equatorial flow occurs even in the absence of African orography, though this flow is muc weaker even when the Indian monsoon rainfall is high. However, the location of the meridional jet near the equator in the Somali region is linked to the Indian monsoon rainfall rather than to the land-sea contrast over Somalia. Also, the presence of African orography, and not the strength of the Indian monsoon, controls the vertical extent of the equatorial meridional wind. In an aqua-planet simulation, the cross-equatorial flow occurs about 30 to the west of the rainfall maximum. Thus, the longitudinal location of the equatorial Somali jet depends upon the occurrence of monsoon heating, but the vertical structure of the jet is on account of the western boundary current in the atmosphere due to the East African highlands under the influence of monsoonal heat source.

Climatic variability in Central Indian Himalaya during the last similar to 1800 years: Evidence from a high resolution speleothem record

Stable isotopes from a U/Th dated aragonite stalagmite from the Central Kumaun Himalaya provide evidence of variation in climatic conditions in the last similar to 1800 years. The delta O-18 and delta C-13 values vary from -4.3 parts per thousand to -7.6 parts per thousand and -3.4 parts per thousand to -9.1 parts per thousand respectively, although the stalagmite was not grown in isotopic equilibrium with cave drip water, a clear palaeoclimatic signal in stalagmite delta O-18 values is evident based on the regional climate data. The stalagmite showed a rapid growth rate during 830-910 AD, most likely the lower part of Medieval Warm Period (MWP), and 1600-1640 AD, the middle part of Little Ice Age (LIA). Two distinct phases of reduced precipitation are marked by a 2 parts per thousand shift in 8180 values towards the end of MWP (similar to 1080-1160 AD) and after its termination from similar to 1210 to 1440 AD. The LIA (similar to 1440-1880 AD) is represented by sub-tropical climate similar to modern conditions, whereas the post-LIA was comparatively drier. The Inter Tropical Convergence Zone (ITCZ) was located over the cave location during wetter/warmer conditions. When it shifted southward, precipitation over the study area decreased. A prominent drop in delta O-18 and delta C-13 values during the post-LIA period may also have been additionally influenced by anthropogenic activity in the area. (C) 2013 Elsevier Ltd and INQUA. All rights reserved.