Boyd's forest dragon (''Lophosaurus boydii)'' is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

arboreal Arboreal locomotion is the locomotion of animals in trees. In habitats in which trees are present, animals have evolved to move in them. Some animals may scale trees only occasionally (scansorial), but others are exclusively arboreal. The hab ...

lizard Lizard is the common name used for all Squamata, squamate reptiles other than snakes (and to a lesser extent amphisbaenians), encompassing over 7,000 species, ranging across all continents except Antarctica, as well as most Island#Oceanic isla ...

in the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Agamidae Agamidae is a family containing 582 species in 64 genera of iguanian lizards indigenous to Africa, Asia, Australia, and a few locations in Southern Europe. Many species are commonly called dragons or dragon lizards. Overview Phylogenetically ...

. The species is native to

rainforest Rainforests are forests characterized by a closed and continuous tree Canopy (biology), canopy, moisture-dependent vegetation, the presence of epiphytes and lianas and the absence of wildfire. Rainforests can be generally classified as tropi ...

s and their margins in the

Wet Tropics The Wet Tropics of Queensland World Heritage Site consists of approximately 8,940 km2 of Australian wet tropical forests growing along the north-east Queensland portion of the Great Dividing Range. The Wet Tropics of Queensland meets all f ...

region of northern

Queensland Queensland ( , commonly abbreviated as Qld) is a States and territories of Australia, state in northeastern Australia, and is the second-largest and third-most populous state in Australia. It is bordered by the Northern Territory, South Austr ...

, Australia. It is the larger of the two species of '' Lophosaurus'' found in Australia. Another species, the southern angle-headed dragon, ''L. spinipes'', is found in southern Queensland and northern

New South Wales New South Wales (commonly abbreviated as NSW) is a States and territories of Australia, state on the Eastern states of Australia, east coast of :Australia. It borders Queensland to the north, Victoria (state), Victoria to the south, and South ...

Etymology

The

generic Generic or generics may refer to: In business * Generic term, a common name used for a range or class of similar things not protected by trademark * Generic brand, a brand for a product that does not have an associated brand or trademark, other ...

name ''Lophosaurus'' stands for "crested lizard", from the Greek ''lophos'' for "crest", and ''saurus'' for "lizard". The

specific name Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...

, ''boydii'', is a reference to

English English usually refers to: * English language * English people English may also refer to: Culture, language and peoples * ''English'', an adjective for something of, from, or related to England * ''English'', an Amish ter ...

-born John Archibald Boyd (1846–1926), who lived in

Fiji Fiji, officially the Republic of Fiji, is an island country in Melanesia, part of Oceania in the South Pacific Ocean. It lies about north-northeast of New Zealand. Fiji consists of an archipelago of more than 330 islands—of which about ...

from 1865 to 1882 and then on a sugar plantation at

Ingham, Queensland Ingham is a rural town and Suburbs and localities (Australia), locality in the Shire of Hinchinbrook, Queensland, Australia. It is named after William Bairstow Ingham and is the administrative centre for the Shire of Hinchinbrook. In the , th ...

, and collected specimens for the

Australian Museum The Australian Museum, originally known as the Colonial Museum or Sydney Museum. is a heritage-listed museum at 1 William Street, Sydney, William Street, Sydney central business district, Sydney CBD, New South Wales. It is the oldest natural ...

. The

binomial authority In taxonomy, binomial nomenclature ("two-term naming system"), also called binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin grammatical forms, altho ...

William John Macleay Sir William John Macleay (13 June 1820 – 7 December 1891) was a Scottish-Australian politician, naturalist, zoologist, and herpetologist. Early life Macleay was born at Wick, Caithness, Scotland, second son of Kenneth Macleay of Keiss and h ...

, who provided the original description of the species in 1884. Additionally, the Kuku Yalanji people of North Queensland named this lizard "Jalbil" which refers not only to this species, but also to the mythological creature who split Snapper Island away from the mainland.

Geographic range and habitat

The species ''Lophosaurus boydii'' is restricted to rainforests and their margins in northern

, Australia, from just north of

Townsville The City of Townsville is a city on the north-eastern coast of Queensland, Australia. With a population of 201,313 as of 2024, it is the largest settlement in North Queensland and Northern Australia (specifically, the parts of Australia north of ...

to near

Cooktown Cooktown is a coastal town and locality in the Shire of Cook, Queensland, Australia. Cooktown is at the mouth of the Endeavour River, on Cape York Peninsula in Far North Queensland where James Cook beached his ship, the '' Endeavour'', for ...

. It is found in both upland and lowland rainforest, and is often seen around Lake Eacham (Yidyam) and Lake Barrine, and in parts of Malanda Falls Conservation Park and at Mossman Gorge. It is recorded using tree-hollows.

Description

Boyd's forest dragon is generally brown or grey above, with some individuals having a green flush. The body is laterally compressed. It has very enlarged cheek scales, a prominent

nuchal The nape is the back of the neck. In technical anatomical/medical terminology, the nape is also called the nucha (from the Medieval Latin rendering of the Arabic , ). The corresponding adjective is ''nuchal'', as in the term ''nuchal rigidity' ...

crest, and a yellow

dewlap A dewlap is a longitudinal flap of skin or similar flesh that hangs beneath the lower jaw or neck of many vertebrates. More loosely, it can be various similar structures in the neck area, such as those caused by a double chin or the submandibula ...

under the chin that is edged with enlarged spines. The tympanum is large and superficial. A

dorsal Dorsal (from Latin ''dorsum'' ‘back’) may refer to: * Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism * Dorsal, positioned on top of an aircraft's fuselage The fus ...

crest, discontinuous with the nuchal crest, consisting of enlarged, hardened and pointed scales, runs down to the base of the tail. Adults are

sexually dimorphic Sexual dimorphism is the condition where sexes of the same species exhibit different Morphology (biology), morphological characteristics, including characteristics not directly involved in reproduction. The condition occurs in most dioecy, di ...

, with males larger than females and having larger, blockier heads. Adult males grow to an average body length (snout-vent length) of about , with the tail adding another ; average body length for adult females is about and tail length is about . Average body mass for adult males is about , and for females is about .

Behavior

Boyd's forest dragon spends the majority of its time perched on the trunks of trees, usually at around head height, although daily movements can exceed on the ground. When approached, it will usually move around to the opposite side of the tree, keeping the trunk between it and its harasser. Unlike most other lizards, Boyd's forest dragon does not bask in the sun, instead letting its body temperature fluctuate with air temperature ( thermoconforming rather than thermoregulating). The one possible exception to this general rule is gravid (pregnant) females, which are often observed sitting on or beside forest roads and exhibit elevated body temperatures. Boyd's forest dragon typically commences activity at dawn and ceases activity at dusk, remaining active even when it rains. Activity is highly seasonal, all but ceasing during the cooler months, when lizards typically move into the rainforest canopy. Both males and females appear to be territorial, with males defending an area of around 1,000 square metres (0.247 acres). Female territories are smaller, with male territories often containing the territories of more than one female. Hatchlings, juveniles and smaller adults can often be found "sleeping" at night at the ends of tree branches with the head pointing back towards the trunk.

Diet

Boyd's forest dragon is a

sit-and-wait predator Ambush predators or sit-and-wait predators are carnivorous animals that capture their prey via stealth, luring or by (typically instinctive) strategies utilizing an element of surprise. Unlike pursuit predators, who chase to capture prey using ...

, catching

prey Predation is a biological interaction in which one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not ki ...

that it spies from its perch, although once on the ground, it will frequently move over a wider area, catching prey as it goes. Its diet consists primarily of

invertebrate Invertebrates are animals that neither develop nor retain a vertebral column (commonly known as a ''spine'' or ''backbone''), which evolved from the notochord. It is a paraphyletic grouping including all animals excluding the chordata, chordate s ...

s, with

earthworm An earthworm is a soil-dwelling terrestrial invertebrate that belongs to the phylum Annelida. The term is the common name for the largest members of the class (or subclass, depending on the author) Oligochaeta. In classical systems, they we ...

s making up a relatively high proportion. Small

fruit In botany, a fruit is the seed-bearing structure in flowering plants (angiosperms) that is formed from the ovary after flowering. Fruits are the means by which angiosperms disseminate their seeds. Edible fruits in particular have long propaga ...

s and

vertebrate Vertebrates () are animals with a vertebral column (backbone or spine), and a cranium, or skull. The vertebral column surrounds and protects the spinal cord, while the cranium protects the brain. The vertebrates make up the subphylum Vertebra ...

s are also occasionally consumed.

Reproduction

Reproduction in ''Lophosaurus boydii'' is via

eggs An egg is an organic vessel in which an embryo begins to develop. Egg, EGG or eggs may also refer to: Biology * Egg cell, the female reproductive cell (gamete) in oogamous organisms Food * Eggs as food Places * Egg, Austria * Egg, Switzerland ...

, with

clutch A clutch is a mechanical device that allows an output shaft to be disconnected from a rotating input shaft. The clutch's input shaft is typically attached to a motor, while the clutch's output shaft is connected to the mechanism that does th ...

sizes varying from one to six eggs. Eggs are about long and wide, and weigh about . Egg size and weight are both higher in upland populations. Females in lowland populations may lay more than one clutch in a season, but clutch sizes are typically smaller than those laid by upland females. The eggs are laid in shallow nests, often in rainforest clearings—both natural and man-made (the verges of roads are particularly popular). The eggs take about 100 days to incubate. Sexual maturity is achieved in around one to two years in lowland populations but probably takes at least a year longer in upland populations.

Predators

Known predators of juvenile and adult Boyd's forest dragon include

grey goshawk The grey goshawk (''Tachyspiza novaehollandiae'') is a strongly built, medium-sized bird of prey in the family ''Accipitridae'' that is found in eastern and northern Australia. The white polymorphism (biology), morph of this species is known as ...

s and

feral pig A feral pig is a domestic pig The pig (''Sus domesticus''), also called swine (: swine) or hog, is an omnivorous, domesticated, even-toed, hoofed mammal. It is named the domestic pig when distinguishing it from other members of the g ...

s. Slaty-grey snakes ('' Stegonotus cucullatus'') have also been known to eat forest dragon eggs.

Parasites

Small orange mites are commonly found on the dewlap and in the groin areas of the legs of Boyd's forest dragon.

References

External links

Boyd's Forest Dragon

Tropical Topics
{{Taxonbar, from=Q2711409 Agamid lizards of Australia Endemic fauna of Australia Lophosaurus Reptiles described in 1884 Reptiles of Queensland Taxa named by William John Macleay