Harold K. Voris

Field Museum of Natural History · Zoology

Divergence dating analyses in systematics provide a framework to develop and test biogeographic hypotheses regarding speciation. However, as molecular datasets grow from multilocus to genomic, sample sizes decrease due to computational burdens, and the testing of fine-scale biogeographic hypotheses becomes difficult. In this study, we use coalescen...

Our knowledge of the biodiversity of Asia and Australasia continues to expand with more focused studies on systematics of various groups and their biogeography. Historically, fluctuating sea levels and cyclic connection and separation of now-disjunct landmasses have been invoked to explain the accumulation of biodiversity via species pump mechanism...

Divergence dating analyses in systematics provide a framework to develop and test biogeographic hypotheses regarding speciation. However, as molecular datasets grow from multilocus to genomic, sample sizes decrease due to computational burdens, and the testing of fine-scale biogeographic hypotheses becomes difficult. In this study, we use coalescen...

Bryozoans are common fouling organisms on immobile permanent substrata. They are epizoic on a variety of mobile living substrata including both nektonic and mobile benthic hosts. Epizoic bryozoans are less common on mobile ephemeral · substrata where the host regularly discards its outer surface. Two cheilostomate bryozoans, Electra angulata (Levin...

Mud snakes (Serpentes: Homalopsidae) are a family of 54 described, mainly aquatic, species primarily distributed throughout mainland Southeast Asia and the Indo-Australian Archipelago. Although they have been the focus of prior research, the basic relationships amongst genera and species remain poorly known. We used a combined mitochondrial and nuc...

Marine snakes represent the most speciose group of marine reptiles and are a significant component of reef and coastal ecosystems in tropical oceans. Research on this group has historically been challenging due to the difficulty in capturing, handling, and keeping these animals for field- and lab-based research. Inexplicable declines in marine snak...

The evolutionary innovations that allow snakes to swallow large prey whole provide a model system for testing how anatomy constrains what predators eat. For a clade of three snake species with the unusual diet of decapod crustaceans, we quantified maximal gape, prey size and feeding behaviour. Fordonia leucobalia eats hard-shelled crabs and had max...

Prior to World War II, traditional hand-operated fishing methods prevailed throughout Southeast Asia. However, by 1950, mechanized diesel-powered trawlers were being introduced and the modern boom-andbust of fisheries was set into motion. Besides targeted fish, squid, and prawns, otter trawls on the bottom brought up a vast diversity of demersal by...

Jagor’s water snake (Enhydris jagorii) is a freshwater snake that is endemic to the Chao Phraya-Ta Chin basin, Thailand. However, habitat change and destruction are the main threats to this snake, where a large area of the wetland has been rapidly transformed into urban and agricultural areas. Moreover, uncontrolled fishing seriously threatens the...

Prior to entering the Straits of Malacca the Muar River meanders nearly at sea level for about 20 kilometers. Much of this portion of the river is influenced by semi-diurnal tides that occur in the Straits. In the 1970s and 1980s several stationary stake nets (kelongs) located adjacent to the town of Muar were operated by local fisherman. Besides t...

Abstract: Conservation of sea snakes is virtually nonexistent in Asia, and its role in human–snake interactions in terms of catch, trade, and snakebites as an occupational hazard is mostly unexplored. We collected data on sea snake landings from the Gulf of Thailand, a hotspot for sea snake harvest by squid fishers operating out of the ports of Son...

The colubroid snake family Homalopsidae contained 10 genera and 34 species of rear-fanged semi-aquatic and aquatic snakes in 1970 with the publication of Gyi's monograph. In 2007 Murphy had updated Gyi's work and the family held the same 10 genera with 37 species plus two genera with uncertain status (Anoplohydrus, Brachyorrhos). Molecular studies...

An assessment of marine elapid snakes found 9% of marine elapids are threatened with extinction, and an additional 6% are Near Threatened. A large portion (34%) is Data Deficient. An analysis of distributions revealed the greatest species diversity is found in Southeast Asia and northern Australia. Three of the seven threatened species occur at Ash...

Two genera of fangless homalopsid snakes Brachyorrhos and Calamophis from eastern Indonesia have been described as basal members of the clade. A third genus belonging to this group from Sumatra, Indonesia is described here based upon morphology. Fangless homalopsid snakes share 19 dorsal scale rows at mid-body, fused dorsal scales above the cloaca,...

Cerberus rynchops has a South Asian distribution. On the eastern edge of its range, it extends to the Mouth of the Irrawaddy, Myanmar and perhaps into the Mergui Archipelago, where it is replaced by Cerberus schneiderii along the Andaman Sea coast of Thailand and coastal Southeast Asia (Murphy et al. 2012). The western edge of the distribution of C...

An assessment of marine elapid snakes found 9% of marine elapids are threatened with extinction, and an additional 6% are Near Threatened. A large portion (34%) is Data Deficient. An analysis of distributions revealed the greatest species diversity is found in Southeast Asia and northern Australia. Three of the seven threatened species occur at Ash...

Abstract.—An assessment of marine elapid snakes found 9% of marine elapids are threatened with extinction, and an additional 6% are Near Threatened. A large portion (34%) is Data Deficient. An analysis of distributions revealed the greatest species diversity is found in Southeast Asia and northern Australia. Three of the seven threatened species oc...

Snakes of the genus Cerberus Cuvier, 1829 occupy a unique, widespread coastal distribution and have a salt-tolerant physiology that allows members of the genus to move across a wide range of salinities from full salt water to freshwater. Cerberus nomenclature is revised based upon morphology and builds on previous molecular studies. Three species h...

Masked water snakes of the genus Homalopsis are abundant in the wetlands of Southeastern Asia. Currently, two species are recognized, the widespread H. buccata Linnaeus and the Mekong drainage endemic H. nigroventralis Deuve. On the basis of morphology we resurrect H. hardwickii Gray and H. semizonata Blyth and describe a new species from Indochina...

During the Cenozoic, Southeast Asia was profoundly affected by plate tectonic events, dynamic river systems, fluctuating sea levels, shifting coastlines, and climatic variation, which have influenced the ecological and evolutionary trajectories of the Southeast Asian flora and fauna. We examined the role of these paleogeographic factors on shaping...

Sea-level variations are the major factor controlling sedimentation as well as the biogeographic patterns at continental margins over late Quaternary times. Fluctuations on millennial time-scales produce locally complex deposits in coasts and on shelves, associated with short-term influence on species development. This article reviews the sedimenta...

The distribution of the big-headed turtle Platysternon megacephalum, Gray 1831 in Thailand was studied from Dec. 2006 to Apr. 2009. Mountain streams of protected and unprotected areas throughout Thailand, except in the southern peninsular region, were ground surveyed. This study confrms the occurrence of P. megacephalum in 1 new and 9 previously re...

A study of stream-dwelling frog assemblages was conducted at 800, 950, and 1250 m in elevation on the Nam San Noi stream, Phuluang Wildlife Sanctuary, north-central Thailand. Three transects, each 100 m long which ran along the stream, were designated at each elevation. Visual encounter surveys were conducted within each transect at night from June...

Previous molecular phylogenetic hypotheses for the Homalopsidae, the Oriental-Australian Rear-fanged Water Snakes indicate that Enhydris, the most speciose genus in the Homalopsidae (22 of 37 species), is polyphyletic and may consist of five separate lineages. We expand on earlier phylogenetic hypotheses using three mitochondrial fragments and one...

The Central Plain is one of the major natural regions of Thailand. It is a wide alluvial plain with little topographic relief consisting of multiple river basins. The many natural and anthropogenic wetland habitats in the region make it an ideal habitat for many aquatic and semi-aquatic species. We document the semi-aquatic snake communities associ...

Aim We seek to relate the present distributions of frogs and snakes of Sundaland and the known geological history of the region. Location From the Isthmus of Kra to Java and Sulawesi. Methods We relate the known ecological requirements of frogs and snakes to their geographical distributions and information on geological history. Results Microhab...

The white-nest swiftlet, Aerodramus fuciphagus, originally lived in large colonies in natural caves, but now it also occurs in man-made buildings. We investigated the patterns of genetic differentiation in two mitochondrial DNA genes (cyt-b and ND2) and eight microsatellite loci among and within colonies of A. fuciphagus from across recently establ...

Homalopsid snakes are widely distributed throughout Southeast Asia and form the ecologically dominant component of the herpetofauna over much of their range. Although they are considered well differentiated from other colubrid lineages, several aspects of their radiation including within-family relationships, temporal patterns of species diversific...

We used species-specific microsatellite loci to detect multiple paternity in two species of homalopsid snakes, Enhydris enhydris and Enhydris subtaeniata. We collected data from nine loci for E. subtaeniata, and four for E. enhydris. Four E. subtaeniata litters and two E. enhydris litters were genotyped. All litters showed multiple paternity with t...

The foraging behavior of Gekko gecko was observed at the visitor complex of the Khao Khiao Open Zoo at the Khao Khiao-Khao Chomphu Wildlife Sanctuary in Chon Buri Province, Thailand. Foraging parameters of G. gecko (foraging period, time spent moving, foraging attempts, foraging success, prey size consumed, and foraging distance) did not vary signi...

Color maps are presented that depict Holocene sea level transgressions and probable submerged lakes on the Sunda Shelf in Southeast Asia. The present-day topography of the Sunda Shelf and the existence of present-day submerged depressions on the Sunda Shelf have been detected through spatial analysis of the Sunda Shelf using the Digital Elevation M...

Amphibians tend to exhibit conservative morphological evolution, and the application of molecular and bioacoustic tools in systematic studies have been effective at revealing morphologically 'cryptic' species within taxa that were previously considered to be a single species. We report molecular genetic findings on two forest-dwelling ranid frogs f...

Tomistoma schlegelii the "False Gharial" (Müller, 1838) is one of the largest yet least-known of the world's 23 crocodilian species, restricted to Indonesia and Malaysia. We compiled and mapped 210 records and overlaid these against geological river systems and current vegetation, in order to assess historic and current distribution, relationship t...

A new species of homalopsine water snake of the genus Enhydris is described from Kalimantan, Indonesia on the basis of three specimens. It differs from its close relative Enhydris doriae (Peters, 1871) in the number of scale rows at midbody, a higher number of lower labials and ventral scales, plate like temporal scales, and a distinctive color pat...

A new species, previously misidentified in museum collections and the literature as E. jagorii, is described. All specimens of the new taxon with specific locality data are from the vicinity of metropolitan Bangkok. It can be distinguished from other Enhydris with 21-23 scale rows at mid-body by the presence of 21 scale rows on the neck, 110-122 ve...

The Khorat Basin is a prominent geographic feature of Indochina, potentially important in the ecology and evolution of semi-aquatic snake communities. We compared community structure and population characteristics of semi-aquatic snakes (taxonomic focus on homalopsine snakes) from localities located in the Khorat Basin, on the mountainous rim of th...

A survey of live and preserved crustaceans from the northern portion of the Gulf of Mexico was conducted to investigate the colonization habits of the barnacle genus Octolasmis. In all, three crustacean orders (Decapoda, Isopoda, and Stomatopoda) comprising 43 families, 78 genera, and 122 species were surveyed. Octolasmis barnacles were observed to...

Aim The biogeography of Southeast Asia has been greatly affected by plate tectonic events over the last 10 Myr and changing sea levels during the Quaternary. We investigated how these events may have influenced the evolution of Cerberus Cuvier, a marine coastal snake belonging to the Homalopsinae (Oriental‐Australian Rear‐fanged Water Snakes). This...

We studied the ecology of four species of coastal marine.homalopsine snakes (Oriental- Australian rear-fanged water snakes) in the Pasir Ris Park mangrove forest, Singapore, using survey methods and radiotelemetry. The snake assemblage at Pasir Ris (220 snakes collected) was dominated by Cerberus rynchops (72.7% of total snakes), a medium-sized pis...

The Homalopsinae (Oriental-Australian rear-fanged water snakes) is a small (34 species, 10 genera) colubrid subfamily notable for its ecological and morphological diversity. Despite considerable interest in the ecology and evolution of this group, phylogenetic relationships within the subfamily are poorly resolved. We present the results of a molec...

The diets of all South-East Asian water snakes of the subfamily Homalopsinae are reviewed. New diet observations for 10 species of homalopsine snakes are presented. The data on four of these, Cantoria violacea, Enhydris doriea, E. longicauda and Gerarda prevostina represent the érst published diet records for these species. The observations for For...

For animals who are unable to take bites out of their food, the size of the food item that can be consumed is constrained by the maximal size of the mouth opening (gape)--snakes are an example of gape-limited predators and they usually swallow their prey whole. Here we describe unique feeding behaviours in two closely related species of snake, whic...

For animals who are unable to take bites out of their food, the size of the food item that can be consumed is constrained by the maximal size of the mouth opening (gape) - snakes are an example of gape-limited predators and they usually swallow their prey whole. Here we describe unique feeding behaviours in two closely related species of snake, whi...

The objective of this research was to redescribe the spatial distribution of Octolasmis muelleri on Callinectes sapidus in order to explore the relationship between the spatial distribution and the size of O. muelleri on C. sapidus. Size distributions of O. muelleri were also investigated in order to elucidate the mechanism of colonization by the c...

AimWe seek to relate the present distributions of frogs and snakes of Sundaland and the known geological history of the region.LocationFrom the Isthmus of Kra to Java and Sulawesi.Methods We relate the known ecological requirements of frogs and snakes to their geographical distributions and information on geological history.ResultsMicrohabitat requ...

AimGlaciation and deglaciation and the accompanying lowering and rising of sea levels during the late Pleistocene are known to have greatly affected land mass configurations in Southeast Asia. The objective of this report is to provide a series of maps that estimate the areas of exposed land in the Indo-Australian region during periods of the Pleis...

Cyprid larvae of the lepadomorph Octolasmis colonize the gill chambers of the edible mangrove crab Scylla seratta (Forskbl, 1755). In a natural population of 856 mangrove crabs from southern Thailand, 260 individuals were infested by 3,670 Octolasmis cor and 1,758 0. angulata, including 1,014 subadults, 168 cyprids, and 38 peduncles of the two spec...

Aim The biogeography of Southeast Asia has been greatly affected by Pleistocene sea-level changes and the consequent alteration of coastline and land mass configurations. We investigated the effect of these Pleistocene events on genetic divergence in Cerberus rynchops, the Bockdam, an Asian water snake (Homalopsinae) associated with tidal mudflats...

Bryozoans are common fouling organisms on sessile, inorganic, hard substrates. They are also epizoans on a variety of living substrates including both nektonic and motile benthic hosts. Epizoic bryozoan s are less common on motile ephemeral substrates where the host regularly discards its outer surface. Two cheilostome bryozoans, Biflustra savartii...

This study examines the prevalence, intensity, abundance, and spatial distribution of fouling bryozoans on 168 blue crabs, Callinectes sapidus, taken from an estuarine environment in the area of Beaufort, North Carolina. Three epizoic bryozoan species were found on the host crabs. These include Alcyonidium albescens Winston and Key, Membranipora ar...

A key to the fully aquatic venomous sea snakes found in the Gulf of Thailand is presented. The key uses external characteristics, numerous illustrations, a minimum of scien- tific terminology, and little or no complex scale counting. This key should be usable by local biologists, Royal Thai Navy personnel, and medical professionals who wish to iden...

Fifty-two recently metamorphosed, juvenile, and young adult pedunculate barnacles, Octolasmis mulleri, were grown individually under laboratory conditions at 25-27°C, fed the marine rotifer Brachionus sp. and the brine shrimp Artemia salina. Growth of the animals was monitored over 10 weeks by periodic measurements of the capitular length, the area...

All adult Octolasmis live permanently fixed to animate hosts by a basal attachment disc. The peduncle connects the disc to the plated capitulum. The area of the capitular plates and the capitular perimeter bordered by plates is assessed for 28 species of Octolasmis. A hypothesis that the species of Octolasmis that live inside decapod gill chambers...

This study examines the barnacle symbionts on 168 blue crab both shallow and deep estuarine environments in the area of B pose of the study was to quantify the prevalence, intensity, a the ectosymbiotic barnacle Chelonibia patula on blue crabs. T was 67%. There was no difference in the prevalence of barna sus the deep environment. Results indicate...