127 research outputs found
Ecology and diversity of herpetofaunal communities in fragmented lowland rainforests in the Philippines
Ph.DDOCTOR OF PHILOSOPH
The Herpetological Importance of Mt. Hamiguitan Range, Mindanao Island, Philippines
We provide the first accounts of the amphibians and reptiles of Mt. Hamiguitan Range in south eastern Mindanao. Three sites were visited: dipterocarp, transitional dipterocarp-montane and mossypygmy forests. The combination of transect sampling, pitfall trapping and microhabitat searches produced records of 34 species (15 frogs, 14 lizards and five snakes). We provide information on the herpetofaunal assemblage of Mt. Hamiguitan including data on species richness, elevational distribution and microhabitat preferences. High levels of species richness and endemism were observed especially in the dipterocarp forest site located outside the boundaries of the protected area. Our data suggest that Mt. Hamiguitan range should be considered an important subcenter of herpetological diversity. Future conservation efforts should focus particularly on lowland forests
Evolutionary loss of complexity in animal signals: cause and consequence
We identified hypotheses for the cause and consequences of the loss of complexity in animal signals and tested these using a genus of visually communicating lizards, the Southeast Asian Draco lizards. Males of some species have lost the headbob component from their display, which is otherwise central to the communication of this genus. These males instead display a large, colorful dewlap to defend territories and attract mates. This dewlap initially evolved to augment the headbob component of the display, but has become the exclusive system of communication. We tested whether the loss of headbobs was caused by relaxed selection, habitat-dependent constraints, or size-specific energetic constraints on display movement. We then examined whether the consequences of this loss have been mitigated by increased signaling effort or com- plexity in the color of the dewlap. It appears the increased cost of display movement resulting from the evolution of large body size might have contributed to the loss of headbobs and has been somewhat compensated for by the evolution of greater complexity in dewlap color. However, this evolutionary shift is unlikely to have maintained the complexity previously present in the communication system, resulting in an apparent detrimental loss of information potential
A giant crocodile skull from Can Tho, named “Dau Sau”, represents the largest known saltwater crocodile (Crocodylus porosus) ever reported from Vietnam
We report on a large crocodile skull recovered from a river bank in August 2010 near Đầu Sấu Bridge, in An Binh, Ninh Kieu District, Cần Thơ Province, in southern Vietnam. As the skull from Cần Thơ, named “Đầu Sấu“ herein, is now deposited in the Vietnam National Museum of Nature, Hanoi, we reinvestigated the circumstances surrounding its discovery and provide exact measurements. Skull length (dorsal mid-point) is 70.7 cm. The morphological features confirm it is from a Saltwater crocodile (Crocodylus porosus), and not a Siamese crocodile (C. siamensis), which historically also occurred throughout the Mekong Delta of Vietnam. Skull measurements are compared with those of other large C. porosus skulls for which reliable estimates of total length are available. We also provide measurements of the prepared skull of “Lolong” (69.8 cm), a 6.17 m long C. porosus captured in the Philippines in 2011. On the basis of known skull length:total length ratios the crocodile from Cần Thơ is estimated to be 6.3-6.8 m long. The skull of Đầu Sấu is likely to have been buried for at least 100 years. We discuss the origin of the local name Đầu Sấu, which has traditional and cultural significance, and provide historical reports of crocodiles in the area. Đầu Sấu is smaller than the largest known C. porosus skull (76 cm), but is the largest ever reported from Vietnam, and one of the largest C. porosus known.
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An Old Lineage of Cyphophthalmi (Opiliones) Discovered on Mindanao Highlights the Need for Biogeographical Research in the Philippines
The arachnid order Opiliones, and the suborder Cyphophthalmi in particular, have recently been used to test biogeographical patterns in Southeast Asia due to their ancient age and extremely low vagility. Here we report the first Cyphophthalmi—two juveniles—known from Mindanao in the southern Philippine Archipelago, and we place them in a molecular phylogeny to test biogeographical hypotheses for their colonization of that island. Five molecular markers were sequenced from one specimen, three from the other, and these sequences were added to a previously completed phylogenetic analysis. The specimens were recovered as members of a clade found almost exclusively on Borneo. Their deep placement within this clade suggests a very old origin and colonization that perhaps involved the mysterious landmass now underlying Mindanao's Zamboanga Peninsula. This species prompts new questions about the abilities of Southeast Asian Cyphophthalmi (Stylocellidae) to disperse and colonize, and it emphasizes how much remains to be understood about the geological history of the Philippines.Organismic and Evolutionary Biolog
Amphibians Of The Indomalayan Realm
The Indomalayan Realm (sometimes termed the Oriental region) encompasses all of South and Southeast Asia, including the Indonesian and Philippine archipelagos, and incorporating the major offshore islands of Sri Lanka, Hainan, and Taiwan, as well as Japan’s Ryukyu
archipelago. The western and northern boundaries follow that of Olson et al. (2001), reaching Pakistan, the Himalaya, and southern subtropical China, although the boundary between the Palaearctic and Indomalayan Realm is somewhat unclear in south-east China. However,
as here defi ned, the eastern boundary between Indomalaya and Australasia, which is usually taken as Wallace’s line (an imaginary line named for Alfred Russell Wallace running between Borneo and Sulawesi, and between Bali and Lombok in Indonesia), is here taken to lie further to the east, such that the region includes all of Nusa Tenggara and a number of islands in Maluku (but excluding Seram, Amboin, Buru, Obi, Halmahera, Tanimbar and a few other smaller islands) (see Tyler 1999)
Species boundaries in Philippine montane forest skinks (Genus Sphenomorphus): three new species from the mountains of Luzon and clarification of the status of the poorly known S. beyeri, S. knollmanae, and S. laterimaculatus
Recent collections of Sphenomorphus beyeri Taylor 1915 from the type locality (Mt. Banahao,
Luzon Isl., Philippines) serve as the basis for a thorough analysis of topotypic variation in external morphology
within the species, and allow for detailed comparisons to other taxa. We clarify the taxonomic status of S.
beyeri with respect to other, phenotypically similar species and evaluate species boundaries between allopatric
populations referred to this taxon. The high elevation (1400–1700 m) population of Sphenomorphus (Brown et
al., 1995a) from the Zambales Mountains and Bataan Peninsula of Luzon Island (previously referred by us to
S. beyeri) is a new species that we describe here. We also describe two additional new species from the isolated,
high elevation (1650–1750 m) forests of the Northern Cordillera and the Sierra Madre of Luzon, specimens
of both of which had been previously identified as S. beyeri. All three new species differ from each other and
all other Sphenomorphus species by scalation, body size, and coloration and all have non-overlapping distributions,
associated with separate, isolated, geological components of Luzon Island.
In this paper we also formally redescribe S. beyeri on the basis of a large series of specimens from the type
locality (Mt. Banahao, southern Luzon Island) that we have accumulated over the last 15 years. We place S.
knollmanae Brown, Ruedas, and Ferner 1995 in synonymy with S. laterimaculatus (Brown and Alcala, 1980) and
redescribe the latter species on the basis of the holotype and 20 additional newly collected specimens from
six localities on the Bicol Peninsula of Luzon Island and Marinduque Island. These and other data suggest
that species boundaries in Philippine Sphenomorphus are poorly understood and that taxonomic diversity is
substantially underestimated and in need of comprehensive taxonomic review
Deep-time convergent evolution in animal communication presented by shared adaptations for coping with noise in lizards and other animals animals
Convergence in communication appears rare compared with other forms of adaptation. This is puzzling, given communication is acutely dependent on the environment and expected to converge in form when animals communicate in similar
habitats. We uncover deep-time convergence in territorial communication between
two groups of tropical lizards separated by over 140 million years of evolution:
the Southeast Asian Draco and Caribbean Anolis. These groups have repeatedly
converged in multiple aspects of display along common environmental gradients.
Robot playbacks to free-ranging lizards confirmed that the most prominent convergence in display is adaptive, as it improves signal detection. We then provide
evidence from a sample of the literature to further show that convergent adaptation among highly divergent animal groups is almost certainly widespread in
nature. Signal evolution is therefore curbed towards the same set of adaptive solutions, especially when animals are challenged with the problem of communicating
effectively in noisy environments
Additions to Philippine slender skinks of the Brachymeles bonitae complex (Reptilia: Squamata: Scincidae) IV: Resurrection and redescription of Brachymeles burksi
The diversity of Philippine amphibians and reptiles has increased over the last few decades, in part due to re-evaluation of species formerly believed to be widespread. Many of these investigations of widespread species have uncovered multiple closely related cryptic lineages comprising species complexes, each restricted to individual Pleistocene Aggregate Island Complexes (PAICs). One group in particular for which widespread cryptic diversity has been common is the clade of Philippine skinks of the genus Brachymeles. Recent phylogenetic studies of the formerly recognized widespread species Brachymeles bonitae have indicated that this species is actually a complex distributed across several major PAICs and smaller island groups in the central and northern Philippines, with numerous species that exhibit an array of digit loss and limb reduction patterns. Despite the recent revisions to the B. bonitae species complex, studies suggest that unique cryptic lineages still exist within this group. In this paper, we resurrect the species Brachymeles burksi Taylor 1917, for a lineage of non-pentadactyl, semi-fossorial skink from Mindoro and Marinduque islands. First described in 1917, B. burksi was synonymized with B. bonitae in 1956, and has rarely been reconsidered since. Evaluation of genetic and morphological data (qualitative traits, meristic counts, and mensural measurements), and comparison of recently-obtained specimens to Taylor’s original description support this species’ recognition, as does its insular distribution on isolated islands in the central portions of the archipelago. Morphologically, B. burksi is differentiated from other members of the genus based on a suite of unique phenotypic characteristics, including a small body size, digitless limbs, a high number of presacral vertebrae, the absence of auricular openings, and discrete (non-overlapping) meristic scale counts. The recognition of this central Philippine species further increases the diversity of non-pentadactyl members of the B. bonitae complex, and reinforces the biogeographic uniqueness of the Mindoro faunal region
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