Djoko T Iskandar

Indonesian Academy of Sciences · Basic Sciences

Little is known about the effects of anthropogenic land-use change on the amphibians and reptiles of the biodiverse tropical forests of Southeast Asia. We studied a land-use modification gradient stretching from primary forest, secondary forest, natural-shade cacao agroforest, planted-shade cacao agroforest to open areas in central Sulawesi, Indone...

The microhylid genus Oreophryne reaches its greatest diversity in the New Guinea region, where more than 60 species have been documented to date. Most Oreophryne are small (<30 mm SVL) and only three species, O. anthonyi, O. idenburgensis and O. inor-nata, exceed 40 mm SVL adult body size. Here we describe a fourth large species of Oreophryne that...

Using molecular genetic data, recognised diversity within the gecko genus Cyrtodactylus has more than doubled, with many lineages that were once thought to be wide‐ranging being delimited into multiple independent species. On the Southeast Asian island of Borneo, there has been a recent renewed focus on reptile taxonomy, as genetic data have demons...

The mountains of New Guinea are home to species-rich but poorly understood communities of stream or torrent-breeding pelodryadid treefrogs. Here we describe a new species of moderately sized torrent-breeding Litoria from the mountains of Papua Province, Indonesia. The new species is most similar to Litoria dorsivena but differs from that species in...

Wallacea—the meeting point between the Asian and Australian fauna—is one of the world's largest centers of endemism. Twenty-three million years of complex geological history have given rise to a living laboratory for the study of evolution and biodiversity, highly vulnerable to anthropogenic pressures. In the present article, we review the historic...

Field biology is an area of research that involves working directly with living organisms in situ through a practice known as “fieldwork.” Conducting fieldwork often requires complex logistical planning within multiregional or multinational teams, interacting with local communities at field sites, and collaborative research led by one or a few of t...

The archipelagos of Wallacea extend between the Sunda and Sahul Shelves, serving as a semi‐permeable two‐way filter influencing faunal exchange between Asia and Australo‐Papua. Forest skinks (Genus Sphenomorphus) are widespread throughout southern Wallacea and exhibit complex clinal, ontogenetic, sexual, and seasonal morphological variation renderi...

Rivers are known to act as biogeographic barriers in several strictly terrestrial taxa, while possibly serving as conduits of dispersal for freshwater-tolerant or -dependent species. However, the influence of river systems on genetic diversity depends on taxa-specific life history traits as well as other geographic factors. In amphibians, several s...

Frogs in the family Ranidae are diverse in Asia and are thought to have dispersed to the Sahul Shelf approximately 10 million years ago, where they radiated into more than a dozen species. Ranid species in the intervening oceanic islands of Wallacea, such as Hylarana florensis and H. elberti from the Lesser Sundas and H. moluccana from eastern Wall...

Field biology is an area of research that involves working directly with living organisms in situ through a practice known as “fieldwork.” Conducting fieldwork often requires complex logistical planning within multiregional or multinational teams, interacting with local communities at field sites, and collaborative research led by one or a few of t...

The paucity of biodiversity assessments in the Palaeotropics has constrained recommendations for tropical forest conservation in areas such as Siberut, one of the Mentawai Islands in Indonesia known for its high endemicity. Taking advantage of information from museum collections amassed from the Indo-Malaya archipelago from the early 20th century o...

Comprehensive assessments of species’ extinction risks have documented the extinction crisis and underpinned strategies for reducing those risks. Global assessments reveal that, among tetrapods, 40.7% of amphibians, 25.4% of mammals and 13.6% of birds are threatened with extinction. Because global assessments have been lacking, reptiles have been o...

Comprehensive assessments of species’ extinction risks have documented the extinction crisis and underpinned strategies for reducing those risks. Global assessments reveal that, among tetrapods, 40.7% of amphibians, 25.4% of mammals and 13.6% of birds are threatened with extinction. Because global assessments have been lacking, reptiles have been o...

Phylogenetic and multivariate analyses of Gekko smithii Gray, 1842 recover a new species Gekko hulk from Peninsular Malay­sia and support the resurrection of G. albomaculatus (Giebel, 1861)

The Lesser Sunda Archipelago offers exceptional potential as a model system for studying the dynamics of dispersal-driven diversification. The geographic proximity of the islands suggests the possibility for successful dispersal, but this is countered by the permanence of the marine barriers and extreme intervening currents that are expected to hin...

Conservation status of Varanus rudicollis

Conservation status of Varanus dumerilii

The widespread parthenogenetic gecko Lepidodactylus lugubris is comprised of several clonal lineages, at least one of which has been known for some time to have originated from hybridization between its maternal ancestor, Lepidodactylus moestus, and a putatively undescribed paternal ancestor previously known only from remote islands in the Central...

Sulawesi's endemic maleo bird Macrocephalon maleo, a megapode that lays its eggs in communal nesting areas of warm sand or soil, is classified as Endangered on the IUCN Red List, with its decline generally attributed to habitat loss and poaching of its large eggs. Despite decades of protection under Indonesian law and numerous field conservation ef...

One of the most urgent contemporary tasks for taxonomists and evolutionary biologists is to estimate the number of species on earth. Recording alpha diversity is crucial for protecting biodiversity, especially in areas of elevated species richness, which coincide geographically with increased anthropogenic environmental pressures - the world's so-c...

The Lesser Sunda Archipelago consists of hundreds of oceanic islands located in southern Wallacea. The Sunda ratsnake, Coelognathus subradiatus, is endemic to the Lesser Sundas and is found on most of the major islands. Mitochondrial DNA was sequenced from snakes representing five of the major islands revealing that levels of sequence divergence be...

Despite a considerable amount of research, the systematics of the ranid genus Huia have remained unresolved, mostly owing to insufficient sampling and morphological similarities. As currently circumscribed, Huia consists of five species, but multiple studies have consistently demonstrated that it is not a monophyletic genus. However, no study has a...

Wallace's and Lydekker's Lines both describe important biogeographic barriers in the Indo-Australian Archipelago, with Wallace's Line demarcating the boundary of the Greater Sunda Shelf and Lydekker's Line indicating the edge of the Sahul continental shelf. Despite their similarities, Wallace's Line has been much more heavily studied than has Lydek...

Biodiversity studies, aside from revealing hidden species from basic, conventional methods to sophisticated technologies, also have several obstacles. Our study showed that almost all variable widespread species comprised of multiple species. On the other hand, some endemic species might be found to be a synonym of a widespread species, and a reaso...

Almost a century ago, the Swiss herpetologist Jean Roux described a new skink species, Mabuia wirzi, from a single specimen from Pulau Nias, an island on the west coast of Sumatra in Indonesia (Roux 1925). The specimen was part of a small collection of reptiles and amphibians made on Nias by the ethnologist Paul Wirz (29.v.1892–1955.i.30), who work...

Within Sundaland, the species diversity of the genus Megophrys is richest in Borneo, with some species restricted to the northern highlands of the island. On the basis of molecular, morphological and acoustic evidence, we describe a new species of large-sized Megophrys, once confused with M. nasuta. The new species Megophrys kalimantanensis sp. nov...

The Lesser Sundas Archipelago is comprised of two parallel chains of islands that extend between the Asian continental shelf (Sundaland) and Australo‐Papuan continental shelf (Sahul). These islands have served as stepping stones for taxa dispersing between the Asian and Australo‐Papuan biogeographical realms. While the oceanic barriers have prevent...

The importance of long-distance dispersal (LDD) in shaping geographical distributions has been debated since the nineteenth century. In terrestrial vertebrates, LDD events across large water bodies are considered highly improbable, but organismal traits affecting dispersal capacity are generally not taken into account. Here, we focus on a recent li...

The Lesser Sundas Archipelago is comprised of two parallel chains of islands that extend between the Asian continental shelf (Sundaland) and Australo-Papuan continental shelf (Sahul). These islands have served as stepping-stones for taxa dispersing between the Asian and Australo-Papuan biogeographic realms. While the oceanic barriers have prevented...

Aim: The Lesser Sunda Islands are situated between the Sunda and Sahul Shelves, with a linear arrangement that has functioned as a two-way filter for taxa dispersing between the Asian and Australo-Papuan biogeographical realms. Distributional patterns of many terrestrial vertebrates suggest a stepping-stone model of island colonization. Here we inv...

In 2011 and 2014, we conducted two expeditions to four islands in the Kei Island group in Maluku Province of eastern Indonesia. We documented and collected 33 species of lizards, snakes, and frogs, and after reviewing historical occurrences in the island group, we accounted for a total of 39 species present in the Kei Islands (26 lizards, 10 snakes...

In 2011 and 2014, we conducted two expeditions to four islands in the Kei Island group in Maluku Province of eastern Indonesia. We documented and collected 33 species of lizards, snakes, and frogs, and after reviewing historical occurrences in the island group, we accounted for a total of 39 species present in the Kei Islands (26 lizards, 10 snakes...

Red List Data/ Conservation Status for Cyrtodactylus quadrivirgatus

There are few examples of primary succession from tropical conditions, especially on land degraded by human activity, e.g. mine wastes. Such studies would assist in informing ecological restoration of these degraded sites. Here, a chronosequence approach was used to investigate early‐stage primary succession on overburden spoil wastes derived from...

Two new species of the dwarf litter frog genus Leptobrachella are described from North and Central Kalimantan, Indonesian part of the Borneo Island. Leptobrachella fusca n. sp. from Bulungan Regency, differs from all congeneric species in the following combination of characters: body small (SVL: 16.3 mm in a male); dorsum uniformly dark brown; side...

We used Massively Parallel High-Throughput Sequencing to obtain genetic data from a 145-year old holotype specimen of the flying lizard, Draco cristatellus . Obtaining genetic data from this holotype was necessary to resolve an otherwise intractable taxonomic problem involving the status of this species relative to closely related sympatric Draco s...

ND2 sequence data for members of the Draco fimbriatus group plus 13 mitochondrial sequence reads obtained from the D. cristatellus holotype This file includes ND2 sequence data obtained via traditional Sanger sequencing for 39 individuals representing Draco cristatellus, D. fimbriatus, D. hennigi, D. punctatus, and D. maculatus, plus 183 base pairs...

The presence of an adhesive abdominal sucker (gastromyzophory) allows tadpoles of certain species of anurans to live in fast-flowing streams. Gastromyzophorous tadpoles are rare among anurans, known only in certain American bufonids and Asian ranids. To date, Huia sumatrana , which inhabits cascading streams, has been the only Sumatran ranid known...

We used Massively Parallel High-Throughput Sequencing to obtain genetic data from a 145-year old holotype specimen of the flying lizard, Draco cristatellus. Obtaining genetic data from this holotype was necessary to resolve an otherwise intractable taxonomic problem involving the status of this species relative to closely related sympatric Draco sp...

We used Massively Parallel High-Throughput Sequencing to obtain genetic data from a 145-year old holotype specimen of the flying lizard, Draco cristatellus . Obtaining genetic data from this holotype was necessary to resolve an otherwise intractable taxonomic problem involving the status of this species relative to closely related sympatric Draco s...

Lepidodactylus pantai is a new species of gecko from the Kei Islands, Maluku, Indonesia that is closely associated with intertidal habitats. This species does not fit cleanly into any of the three species groups described for the genus because it possesses the unique combination of both divided terminal scansors on all toes and a nearly completely...

Invasions of poisonous species can cause rapid population declines among native fauna because predators are naïve and often vulnerable to these toxins. The recent invasion of Madagascar by the poisonous Asian common toad, Duttaphrynus melanostictus, has sparked international attention (Kolby, 2015), as well as research and conservation efforts to p...

We investigated diminutive day geckos (SVL < 40 mm) of the genus Cnemaspis (Cnemaspis kandiana Group) from mainland Sumatra and islands along its western margin (Nias, Siberut, Pagai, and Enggano). The assemblage includes several species based on morphological evidence, five of which we describe as new. The new species occur in the Sumatran provinc...

The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & Nemésio 2007; Donegan 2008, 2009; Nemésio 2009a–b; Dubois 2009; Gentile & Snell 2009; Minelli 2009;...

This plot is not part of the published stance but derives from it. The plot shows the number of authors by geographic region (courtesy of Dr. Diego Astua).

The Asian common toad (Duttaphrynus melanostictus) is a human commensal species that occupies a wide variety of habitats across tropical Southeast Asia. We test the hypothesis that genetic variation in D. melanostictus is weakly associated with geography owing to natural and human-mediated dispersal facilitated by its commensal nature. Phylogenetic...

Genetic diversity and similarity of six rice cultivars were analyzed by potato starch gel electrophoresis. Three local cultivars, 'Hawara Batu', 'Pandan Wangi', and 'Singkarak' were already homozygous for all 23 examined loci. Two cultivars have a rare allele, specific for each cultivar. White glutinous is the most polymorphic cultivar in having th...

Sumatra is the 6th largest island in the world which has fascinating biodiversity, including herpetofauna. Unfortunately, Sumatran herptofauna is poorly understood, either its diversity or other biological aspects (e.g. feeding activity and prey composition). Given that Ranidae is a widespread species, no information or studies on the feeding activ...

We describe a new species of fanged frog (Limnonectes larvaepartus) that is unique among anurans in having both internal fertilization and birth of tadpoles. The new species is endemic to Sulawesi Island, Indonesia. This is the fourth valid species of Limnonectes described from Sulawesi despite that the radiation includes at least 15 species and po...

A new species of gekkonid lizard Hemiphyllodactylus engganoensis sp. nov. from Pulau Enggano, southwestern Sumatra, Indonesia is differentiated from all other congeners by having the unique combination of a maximum SVL of 37.3 mm; six chin scales; no enlarged postmentals; five circumnasal scales; three or four scales between the supranasals; 12 sup...

Book Chapter

Aim Widespread species found in disturbed habitats are often expected to be human commensals. In island systems, this association predicts that dispersal will be mediated by humans. We investigated the biogeographical relationships among populations of a widespread tree skink that inhabits coastal forest and human-cultivated plantations in Southeas...