The Colour Changes In Lizards, Particularly In Phrynosoma

The activities of the melanophore system of Phrynosoma in comparison with that of Chamaeleo may be stated categorically in the following way. I. The blanching of Phrynosoma blainvillii is due (1) to the action of its concentrating nerve-fibres on its melanophores, (2) to the action of a hydrohumour, probably adrenalin, on the same cells, (3) to the direct response of these cells to darkness, and (4) to high temperatures. II. The blanching of Chamaeleo is due to the first, third, and fourth of these factors. Whether the second factor is effective in this lizard is not yet determined. III. The darkening of Phrynosoma is due (5) to the action of a pituitary neurohumour on its melanophores, (6) to the direct response of these cells to strong light, and (7) usually, to low temperatures. There are no dispersing nerve-fibres known in Phrynosoma. IV. The darkening of Chamaeleo is due to the sixth and probably to the seventh of these factors. This lizard presents strong indications of possessing dispersing nerve-fibres. Whether it darkens from a pituitary neurohumour or not is unknown

Corytophanes cristatus

Number of Pages: 6Integrative BiologyGeological Science

Sceloporus occidentalis

Number of Pages: 17Integrative BiologyGeological Science

HABITAT UTILIZATION BY THE TEXAS HORNED LIZARD (PHRYNOSOMA CORNUTUM) FROM TWO SITES IN CENTRAL TEXAS

The Texas Horned Lizard (Phrynosoma cornutum) is found in a variety of habitats. Although several studies have been conducted on habitat use by this species, none have been performed in central Texas, a more mesic habitat than most of those previously studied. This area is of special interest because horned lizard populations have been experiencing sharp declines in central Texas over the last approximately 50 years. We collected habitat data at two sites in central Texas, Camp Bowie and Blue Mountain Peak Ranch. Microhabitat data included canopy cover and ground cover from digitized photographs of Daubenmire quadrats; macrohabitat variables included vegetation height and length, cactus height, soil penetrability, woody plant species richness, tree density, tree diameter at breast height (DBH), and density of ant mounds collected along 100-m by 2-m transects. Similar patterns of habitat use were observed between the two sites. At Blue Mountain Peak Ranch, lizards appeared to be located in areas with a diversity of ground cover types, as observed in previous studies. At Camp Bowie, vegetation encroachment limited lizards in some areas to the use of roads and road margins. Implementation of prescribed burns or other vegetation management could create the preferred ground cover mosaic at such sites

Xenosaurus grandis

Number of Pages: 4Integrative BiologyGeological Science

Conservation of amphibians and reptiles in Indonesia: issues and problems

Indonesia is an archipelagic nation comprising some 17,000 islands of varying sizes and geological origins, as well as marked differences in composition of their floras and faunas. Indonesia is considered one of the megadiversity centers, both in terms of species numbers as well as endemism. According to the Biodiversity Action Plan for Indonesia, 16% of all amphibian and reptile species occur in Indonesia, a total of over 1,100 species. New research activities, launched in the last few years, indicate that these figures may be significantly higher than generally assumed. Indonesia is suspected to host the worldwide highest numbers of amphibian and reptile species. Herpetological research in Indonesia, however, has not progressed at a rate comparable to that of neighboring countries. As a result, the ratio of Indonesian species to the entirety of Southeast Asian and Malesian species has “declined” from about 60% in 1930 to about 50% in 2000, essentially a result of more taxa having been described from areas outside Indonesia. Many of these taxa were subsequently also found in Indonesia. In the last 70 years, 762 new taxa have been described from the Southeast Asia region of which only 262 were from Indonesia. In general, the herpetofauna of Indonesia is poorly understood compared to the herpetofauna of neighboring countries. This refers not only to the taxonomic status, but also to the basic biological and ecological characteristics of most of the species. Moreover, geographic distribution patterns for many species are only poorly known. In view of the alarming rate of forest loss, measures for more effective protection of the herpetofauna of Indonesia are urgently required. The status of virtually all of the Indonesian species, e.g. in terms of IUCN categories, remains unknown, and no action plans have been formulated to date. In addition, research results on Indonesia’s amphibian and reptile fauna have often not been made available in the country itself. Finally, there is a clear need to organize research activities in such a way that a larger segment of the Indonesian population becomes aware of the importance of the herpetofauna as an essential component of the country’s biodiversity. To address these issues, this paper (1) gives an overview of the herpetofauna as part of Indonesia’s biodiversity, (2) outlines the history of herpetological research in the region, (3) identifies major gaps in our knowledge of the Indonesian herpetofauna, and (4) uses this framework for discussing issues and problems of the conservation of amphibians and reptiles in Indonesia. In particular, the contents and shortcomings of compilations of lists of protected or threatened species by national and international authorities are discussed, major threats to the Indonesian herpetofauna or certain components thereof are described, and a set of measures for better longterm conservation is proposed.Abstrak.—Indonesia adalah suatu negara kepulauan yang terdiri dari sekitar 17.000 pulau dengan ukuran bervariasi dan mempunyai asal usul geologi yang kompleks seperti yang terlihat dalam komposisi tumbuhan dan hewannya. Indonesia, sebagai salah satu pusat keanekaragaman yang terbesar di dunia, baik dari segikekayaan alam jenisnya maupun dari segi tingkat endemisitasnya. Menurut Biodiversity Action Plan for Indonesia, 16% dari amfibi dan reptil dunia terdapat di sini, dengan jumlah lebih dari 1100 jenis. Kegiatan penelitian yang dilaksanakan pada masa yang baru lalu menunjukkan bahwa jumlah tersebut di atas masih jauh di bawah keadaan yang sebenarnya. Indonesia mungkin sekali sebuah negara yang mempunyai jumlah amfibi dan reptil terbesar di dunia. Yang patut menjadi pertimbangan ialah bahwa penelitian amfibi dan reptil di Indonesia jauh lebih lambat di bandingkan dengan kemajuan di negara tetangga. Sebagai gambaran, jumlah jenis di Indonesia apabila dibandingkan dengan jumlah jenis di seluruh Asia Tenggara dalam kurun waktu 70 tahun telah merosot dari 60% menjadi 50%. Hal ini terjadi karena jumlah taksa baru kebanyakan ditemukan di luar Indonesia. Banyak diantara jenis-jenis tersebut kemudian ditemukan di Indonesia. Dalam 70 tahun terakhir, 762 jenis taksa dipertelakan dari luar Indonesia dan hanya 262 pertelaan dari Indonesia. Pada umumnya herpetofauna Indonesia tidak banyak dikenal, baik dari segi taksonomi, ciri-ciri biologi maupun ciri-ciri ekologinya. Daerah penyebaran suatu jenis sangat sedikit diketahui. Meninjau dari cepatnya penebangan dan pengalihan fungsi hutan, usaha untuk melindungi komponen biologi (dalam hal ini amfibi dan reptil) sangat diperlukan. Hampir semua status perlindungan baik secara nasional maupun dengan mengikuti kategori IUCN atau CITES tidak banyak diketahui atau dipahami. Kebanyakan informasi mengenai organisme Indonesia sulit diperoleh di dalam eri. Sebagai akibat, maka diperlukan suatu mekanisme untuk mengatur kegiatan penelitian sedemikian rupa sehingga timbul kesadaran bahwa amfibi dan reptil merupakan salah satu komponen yang sangat berharga dari kekayaan keaneka-ragaman Indonesia. Makalah ini memberikan (1) gambaran komponen biodiversitas herpetofauna Indonesia, (2) memaparkan sejarah perkembangan herpetologi di Indonesia, (3) mengidentifikasi kekosongan dalam pengetahuan herpetologi di Indonesia, (4) memaparkan masalah dan jalan keluar dalam konseravsi keanekaragaman herpetofauna Indonesia. Daftar herpetofauna Indonesia yang dilindungi undang-undang, CITES dan IUCN dibahas, hewanhewan yang mulai terancam dan kiat untuk melindunginya dibahas

Concepts, Belief, and Perception

At least in one well-motivated sense of ‘concept’, all perception involves concepts, even perception as practiced by lizards and bees. That is because—the paper argues—all perception involves belief

Sauromalus hispidus

Number of Pages: 4Integrative BiologyGeological Science

Urosaurus graciosus

Number of Pages: 3Integrative BiologyGeological Science