Psammophilus

DANIEL, J.C. (1970): Occurrence of the rock lizard (Psammophilus sp.) in Tirukkalikkunram Hill, Chingleput Dt., Tamil Nadu. – J. Bombay Nat. Hist. Soc., 66 (3) [1969]: 632.

Psammophilus blanfordanus STOLICZKA, 1871

Blanfords Rock Agama

ARUNA, C., REDDY, T.B. & M.V.S. RAO (1993): Feeding ecology of Psammophilus blanfordanus (Stoliczka). – J. Bombay Nat. Hist. Soc., 90 (2): 295-296.

JEE, J., MOHOPATRA, B.K., DUTTA, S.K. & G. SAHOO (2016): Sources of calcium for the agamid lizard Psammophilus blanfordanus during embryonic development. – Acta Herp. 11 (2): 171-178.

We determined the sources of calcium for the developing embryo and the parallel changes in eggshell structure in the Indian agamid lizard Psammophilus blanfordanus. The developing eggs were opened at 0 (freshly laid), 10, 20, 30, 35, 38, and 40 days of incubation and at hatching (day 41) and subjected to chemical and structural analyses. The oval and flexible-shelled eggs had undergone significant changes in size (40% increase in length, 68% increase in breadth and 315% increase in weight) from laying to hatching. The fresh eggshell contained 2.76 mg (12.51%) calcium whereas the hatched eggshell had only 1.02 mg (7.20%), or a 63% reduction from its original content. The yolk + fluids fraction provides only 0.47 mg to the 1.76 mg of calcium in the hatchling, the rest being resorbed from the eggshell during development. The fresh eggshell (62 μm thick) had a rough granular structure in its calcareous layer with near uniform rectangular/polygonal fields made up of globules of varying sizes. The membrane layer had a multilayered mat of interwoven, irregularly oriented and bifurcated, fibres of uneven thickness. The spherical globules were absent at several places in the hatched eggshell as a result of eggshell calcium utilisation by the developing embryo. Hence, like that of most reptiles, the eggshell of Psammophilus blanfordanus also acts as a secondary source of calcium for the developing embryo. The embryo utilizes the eggshell calcium towards the end of development.

MISHRA, A. (2021): Interspezifische Wechselwirkungen zwischen den Agamen Calotes versicolor und Psammophilus blanfordanus (Sauria: Agamidae: Draconinae). – Sauria, Berlin, 43 (3): 65-68.

MURTHY, T.S.N. & T. VENKATESWARLU (1980): Record of the rock-lizard, Psammophilus blandfordanus (Stoliczka) (Sauria: Agamidae) in Araku Valley, Eastern Ghats (Andhra Pradesh), India. – J. Bombay Nat. Hist. Soc., 76 (3): 524.

SHARMA, P. & G. SELVARAJ (2017): Natural history notes: Psammophilus blanfordanus (Blanford’s Rock Agama). Diet. – Herpetol. Rev., 48 (1): 200.

SINGH, D.K., JENA, N. & N. MOHANTY (2016): Seasonal variation in nucleic acids, protein and certain enzymes in testis and epididymis of common indian rock lizard, Psammophilus blanfordanus. – The Bioscan, 11 (4): 2137-2141.

STOLICZKA, F. (1871): Notes on new or little-known Indian lizards. - Proc. asiat. Soc. Bengal (Calcutta), 1871: 192-195.

VYAS, R. (2000): First record of Psammophilus blanfordanus (Stoliczka 1871) (family: Agamidae) from Gujarat, India. – J. Bombay Nat. Hist. Soc., 97 (3): 432-433.

Psammophilus dorsalis GRAY, 1831

South Indian Rock Agama

BALAKRISHNA, S. & N. ACHARI (2014): Preliminary observations on the ovipositional behavior of the Peninsular Rock Agama Psammophilus dorsalis (Gray, 1831) from Savandurga forest area of Southwestern Karnataka, India. - Herpetology Notes, 7: 319-322.

BALAKRISHNA, S. (2014): Predation of Black Rat Rattus rattus (Rodentia: Muridae) by the rock lizard Psammophilus dorsalis (Squamata: Agamidae) from sub-urban Bangalore, Karnataka. – Herpetol. Notes, 7: 519-520.

BALAKRISHNA, S., BATABYAL, A. & M. THAKER (2016): Dining in the City: Dietary Shifts in Indian Rock Agamas across an Urban–Rural Landscape. – Journal of Herpetology, 50 (3): 423-428.Rapid urbanization is a growing threat to biodiversity, causing wide-scale extirpation of species from their natural habitats. Some species such as rock agamas, Psammophilus dorsalis, seem to be sufficiently tolerant and continue to persist in urban environments. Given that urbanization alters species composition at multiple trophic levels, we expect a shift in the diet composition and hunting modes of populations across rural and urban areas. Based on identified contents from stomach flushes, we found that P. dorsalis are generally myrmecophagous, and their diet is mainly composed of ants (Hymenoptera: Formicidae). Diet of males and females in each area overlapped highly (80–91%), even though males were significantly larger than females. Dietary overlap between urban and rural populations also was high (80.3%). Surprisingly, rural lizards had lower body mass indices than did urban lizards, despite the greater diversity of prey types and the larger volume of food consumed. This species uses a sit-and-wait hunting strategy, but we found that the rate of movement of males was higher in rural areas compared to urban areas, which likely results in higher energy expenditure. Individuals of P. dorsalis do not seem to be negatively affected by urbanization but instead manage to hunt in and around the small patches of vegetation that remain, enabling them to maintain a higher body condition than that of lizards in undisturbed rural habitats.

BATABYAL, A. & M. THAKER (2017): Signalling with physiological colours: high contrast for courtship but speed for competition. – Anim. Behav., 129: 229-236.

Dynamic physiological colour change allows animals to alter colours and patterns for communication, camouflage and thermoregulation. Using reflectance spectrometry and digital photography, we found that males of the Indian rock agama, Psammophilus dorsalis, can rapidly express intense colours that are different from the neutral state and specific to the social context. The distinct bands on males shifted between yellow and red (dorsal) and between orange and black (lateral) within seconds, and the resulting colour pattern was diametrically different depending on whether males were in courtship or aggressive interactions. Although males showed higher chromatic contrast when courting females, the colour change was faster during competitive encounters with other males. The nature of this social colour communication also differed across populations in anthropogenically disturbed landscapes. Compared to males from rural areas, suburban males were slower to change colour and showed duller and paler colours during staged social encounters. Consistent with other disturbance-induced shifts in phenotypic traits seen in numerous taxa, we provide the first evidence that social signalling through dynamic colour change in terrestrial vertebrates is also affected by urbanization.

BHAVE, R., DEODHAR, S. & K. ISVARAN (2017): Intrinsic factors are relatively more important than habitat features in modulating risk perception in a tropical lizard. – Behav. Ecol. Sociobiol., 71 (10): 146.

Anti-predator responses in animals are dynamic and depend on multiple factors. However, most of our understanding about animal escape responses comes from studies which examine only a small set of factors at a time and are done over a short period of animal life spans. This limits our understanding of the dynamic nature of animal escape behaviour and the relative importance of individual factors in determining their escape behaviour. We used a repeated-measures study design to assess the anti-predator response of a wild population of a sexually dimorphic tropical lizard, Psammophilus dorsalis. We followed marked individuals throughout their breeding lifespan, repeatedly assayed their escape response and measured representative intrinsic and extrinsic factors that could modulate their escape response. Our findings suggest that intrinsic factors, such as sex and body size, influenced escape response relatively more than extrinsic factors did, such as distance to refuge and perch height. Although individual variables influenced escape behaviour, in a direction mostly consistent with predictions from optimal escape theory, the interaction between factors led to novel insights into how animals dynamically evaluate multiple and changing costs throughout their lifetime to evade predation.

GRAY, J.E. (1831): A synopsis of the species of Class Reptilia. - In: Griffith, E & E. Pidgeon: The animal kingdom arranged in conformity with its organisation by the Baron Cuvier with additional descriptions of all the species hither named, and of many before noticed. Whittaker, Treacher and Co.

RADDER, R.S., SAIDAPUR, S.K. & B.A. SHANBHAG (2005): Population density, microhabitat use and activity pattern of the Indian rock lizard, Psammophilus dorsalis (Agamidae). - Curr. Sci., 89: 560-566.

RADDER, R.S., SAIDAPUR, S.K. & B.A. SHANBHAG (2006): Big boys on top: effects of body size, sex and reproductive state on perching behaviour in the tropical rock dragon, Psammophilus dorsalis. – Anim. Biol. (Leiden), 56 (3): 311-321.

Perching behaviour, in relation to sex, body size and reproductive phases, was studied in the field in a population of the tropical rock lizard, Psammophilus dorsalis. Adult lizards (n = 14 males and 16 females) were marked by toe clipping in November 2001. They were observed at intervals (n = 10 times) over the next 18 months encompassing post-breeding (December-early March), recrudescence (late March-April) and breeding (May-August) phases. In the post-breeding phase, males perched at lower heights. They began perching higher during the recrudescence phase with the highest perches in the breeding phase. In comparison to females, the males perched higher than females all year round and showed greater among-individual variations in perch height. The bigger males perched at greater heights compared to smaller ones during recrudescence and breeding phases. No such trend was evident during the post-breeding phase and perch height was not related to body size. Females moved within a narrow range of heights from the substrata and showed no size-specific relationship in perch selection throughout the reproductive cycle. Selection of higher perches by the males, despite high predation risk, possibly helps in territory defence, courtship displays and in advertising their presence to conspecifics. Further, size-specific perch selection prior to and during the breeding period, suggests that size vis-à-vis age and reproductive cycle also influences selection of perch height in males. In females perching close to the substrata, refuge sites and food sources, seems to be associated with escape from predators, foraging benefits and, in turn, reproductive fitness. Thus, in the seasonally breeding P. dorsalis, sex and reproductive status determine the complex pattern of perching behaviour and, possibly, circulating levels of androgens drive the bigger boys on top in accordance with their size or age.

RAMANUJAN, S.G.M. (1931): Occurrence of Charasia dorsalis outside the Mysore Plateau. – J. Bombay Nat. Hist. Soc., 34 (4): 1086.

SREEKAR, R., DEODHAR, S. & Y. KULKARNI (2010): Predation on Hemidactylus treutleri (Squamata: Gekkonidae) by the peninsular rock agama Psammophilus dorsalis (Squamata: Agamidae) in Rishi Valley, Andhra Pradesh, India. – Herpetology Notes, 3: 33-35.

Report on a predation event by an adult Psammophilus dorsalis on a Hemidactylus treutleri, observed at Rishi Valley, Andhra Pradesh, India. Hemidactylus treutleri is recorded for the first time outside of its type locality extending its range.

SRINIVAS, S.R., SHIVANANDAPPA, T., HEGDE, S.N. & H.B.D. PARKER (1995): Sperm storage in the oviduct of the tropical rock lizard, Psammophilus dorsalis. – Journal of Morphology, 224 (3): 293-301.

VEERANAGOUDAR, D.K., BHAGYASHRI, A.S. & S.K. SAIDAPUR (2010): A novel thermoregulatory behavior in a gravid rock lizard, Psammophilus dorsalis. - Herpetology Notes. 3: 101-103.

zurück / back