|
Literatur und Schriften
Hornagamen Rostral appendages occur in a very small number of species spread across the entire clade of iguanian lizards. The five species of Sri Lankan agamid lizards of the poorly known endemic genus Ceratophora show remarkable variation in the morphology and development of rostral appendages, which are absent in two species and present in the other three. Parsimony and Bayesian comparative methods do not robustly resolve whether the appendage evolved once (with two losses), twice (with one loss) or thrice independently. The appendage in C. tennentii is leaf-shaped, present in juveniles and monomorphic in adults. It is quite dissimilar to the appendages in C. aspera and C. stoddartii which are hornshaped, absent in juveniles and dimorphic in adults. Ceratophora stoddartii is more closely related to C. erdeleni, which lacks the rostral appendage, than it is to C. aspera. The combined morphological, allometric and phylogenetic evidence suggests rostral appendages evolved three times within Ceratophora: perhaps once as a result of natural selection for crypsis (in C. tennentii) and twice as a result of sexual selection (in C. aspera and C. stoddartii). Our results suggest that these unusual ornaments can evolve by more than one mechanism and more readily than is suggested by their low frequency among iguanian lizards.
Hornagame / Spitznase / Sri Lanka Horned Agama GÜNTHER, A. (1864): The Reptiles of British India. - London (Taylor & Francis), xxvii + 452 pp. KRVAVAC, M., BOPAGE, M., WEWALWALA, K., BJELIC-CABRILO, O., POPOVIC, E. & O. JOVANOVIC (2015): Reproductive behavior of the vulnerable Rough Nose Horned Lizard, Ceratophora aspera (Sauria, Agamidae) from Sri Lanka. – Russ. J. Herpetol., 22 (2): 145-148. Here we provide the first information of the egg-laying behavior of the threatened Rough Nose Horned Lizard (Ceratophora aspera) from lowland Sri Lanka. The observation was recorded in captivity and the record consists of digging of the nest hole to lay the eggs, laying of the eggs, scraping of the soil to bury the eggs, compression of the soil, camouflage of the nest and duration of the incubation period.
Hornagame PETHIYAGODA, R. & K. MANAMENDRA-ARACHCHI (1998): A revision of the endemic Sri Lankan agamid lizard genus Ceratophora, Gray, 1835, with description of two new species. – Journal of South Asian Natural History, 3: 1-50.
Hornagame PETHIYAGODA, R. & K. MANAMENDRA-ARACHCHI (1998): A revision of the endemic Sri Lankan agamid lizard genus Ceratophora, Gray, 1835, with description of two new species. – Journal of South Asian Natural History, 3: 1-50.
Stachelnase / Mountain Horned Agama BARTELT, U. (1995): Bemerkungen zur Haltung und Nachzucht der Hochlandagame Ceratophora stoddarti GRAY, 1834 (Sauria: Agamidae). - Sauria, Berlin, 117 (4): 11-16. (1477) BARTELT, U. (1996): Ein “Nashorn” im Terrarium. – Die Aquar. Terrar. Z., Stuttgart, 49 (6): 376-379. BARTELT, U. & P. JANZEN (2007): Die Hornagame Ceratophora stoddartii im Biotop und im Terrarium. – Draco, Münster, 8 (2): 34-37. CRUSZ, H. & E.V. MILLS (1970): Partasites of the relict fauna of Ceylon. 1. Scanthocephalus serendibensis sp. nov., from the Ceylon hornnosed lizard, Ceratophora stoddarti Gray. – Annls Parasit. hum. comp., 45: 13-19. DIECKMANN, M. (2011): Ceratophora stoddartii (GRAY, 1834). – Iguana, 24 (2): 17-22. UDAGEDARA, U.S.C & K.A.P.M.K. KARUNARATHNA (2014): Ceratophora stoddartii from Kegalle District (Sabaragamuwa Province), Sri Lanka. – Taprobanica, 6 (1): 59. WILLEY, A. (1906): Viviparity of Cophotis ceylanica and oviparity of Ceratophora stoddartii. – Spol. Zeylan., 3: 235-237.
Rhinoceros Agama AMARASINGHE, A.A.T., KARUNARATHNA, D.M.S. & D. WARAKAGODA (2007): The endangered Sri Lanka Whistling Thrush Myophonus blighi eats an endangered lizard. – BirdingASIA, 7: 83-84. DE SILVA, A., GOONEWARDENE, A., BAUER, A. & J. DRAKE (2005): Ceratophora tennentii GÜNTHER & GRAY, in TENNENT, 1861 (Reptilia: Agamidae) some notes on ist ecology. – In: De Silva, A. (ed.): The diversity of the Dumbara Mountains. – Lyriocephalus Special Issue Vol. 6 (1/2): 55-62. GÜNTHER, A. (1861): Description of Ceratophora tennentii. – In: “Tennent, J.E.: Sketches of the natural history of Ceylon”. London, Longman & Co., 500 pp. MANTHEY, U. (1979): Das Portrait: Ceratophora tennenti (Hornagame). – Sauria, Berlin, 1 (1): 1-2. RODRIGO, R.K. & D. JAYANTHA (2004): An observation of the foraging behavior of Ceratophora tennentii Günther, 1861 Knuckles Forest Range in Sri Lanka. - Reptile RAP, 6: 11. SILVA, A. DE, MEEK, R, BAUER, A., GOONEWARDENE, S., DRAKE, J., DASANAYAKA, R.D.C.S.K., AMARAKOON, A.M.R.K. & M.M. GOONASEKERA (2005): First studies on the thermal ecology of Ceratophora tennentii: (Sauria: Agamidae) inhabiting the cloud forests of Knuckles Massif, Sri Lanka. – In: The Diversity of Dumbara Mountains (Knuckles Massif, Sri Lanka): With special reference to its herpetofauna. Lyriocephalus Special issue, 2005 February, Volume 6 Numbers 1 & 2: 65-71. ISSN 1391 – 0833. SOMAWEERA, R., MEEGASKUMBURA, M., BOWATTE, G. AND N. WIJAYATHILAKA (2015): Conservation in a changing landscape: habitat occupancy of the Critically Endangered Tennent's Leaf-nosed Lizard (Ceratophora tennentii) in Sri Lanka. - Journal of Natural History 49(31/32): 1961-1985. Landscape modification is a key driver of global species extinction. Thus, understanding how species react to changes is essential for effective conservation management in modified landscapes.Weexamined the impact of selected land use patterns on the critically endangered Ceratophora tennentii in the Knuckles mountain range of Sri Lanka where lizards occupy patches of both natural undisturbed forests and modified plantations – evidently, those with a forest canopy. We tested three potential explanations for non-random habitat selection: availability of suitable microhabitat pockets, availability of prey and direct threats from humans. The microhabitat pockets occupied by the lizards were characterised by shade, humidity and the density of perches. Most lizards were found in mixed cardamom forests followed by natural forests and cardamom plantations, but none were observed in the pine plantations. Food availability showed similar patterns among habitats. Direct mortality by humans did not influence the distribution of this species. Our work indicates that habitat modifications that retain the structural complexity of the vegetation would still permit the existence of the species in densities equal to or greater than that of undisturbed forest patches. It adds to a growing body of literature that signifies the importance of disturbed habitats (intermediate disturbance hypothesis) in protecting threatened species of fauna. It is highly unlikely that some disturbed habitats will be ever be returned to their former pristine state in time frames that are important for species’ conservation. Hence, attention is needed in developing suitable approaches to manage and conserve species across disturbed habitats. Measures of physiological performance capacity, such as bite force, form the functional basis of sexual selection. Information about fighting ability may be conveyed through a structural feature such as a rostrum (i.e. horn) or a colour signal and thereby help reduce costly conflict. We quantified sexual dimorphism in key traits likely to be the targets of sexual selection in Tennent’s leaf-nosed lizard (Ceratophora tennentii) from Sri Lanka, and examined their relationship to bite force and body condition. We found body length and bite force to be similar for males and females. However, head length was significantly greater in males and they had significantly more conspicuous throats and labials (chromatic contrast and luminance) than females. Males also had a proportionally larger rostrum, which we predicted could be an important source of information about male quality for both sexes. Rostrum length was correlated with throat chromatic contrast in males but not females. Nonetheless, the rostrum and aspects of coloration did not correlate with bite force or body condition as we predicted. We have no information on contest escalation in this species but if they rarely bite, as suggested by a lack of difference in bite force between males and females, then bite force and any associated signals would not be a target of selection. Finally, males and females had similar spectral reflectance of the mouth and tongue and both had a peak in the ultra-violet, and were conspicuous to birds. Lizards only gaped their mouths during capture and not when threatened by a potential predator (hand waving). We hypothesize that conspicuous mouth colour may act as a deimatic signal, startling a potential predator, although this will need careful experimental testing in the future. |
|||||||||