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65-510: The petaltails of the family Petaluridae are among the most ancient of the extant true dragonflies (infraorder Anisoptera), having fossil members from as early as the Jurassic , over 150 million years ago. A 2024 molecular phylogeny found that the petaltails comprise two clades , a Gondwanan clade and a Laurasian clade. Their divergence time was estimated at 160 million years ago. Modern petalurids include only 11 species, one of which,

130-457: A Hemianax ephippiger native to North Africa, and an unidentified darter species. In Kamchatka , only a few species of dragonfly including the treeline emerald Somatochlora arctica and some aeshnids such as Aeshna subarctica are found, possibly because of the low temperature of the lakes there. The treeline emerald also lives in northern Alaska , within the Arctic Circle , making it

195-631: A reed or other emergent plant, and moults ( ecdysis ). Anchoring itself firmly in a vertical position with its claws, its exoskeleton begins to split at a weak spot behind the head. The adult dragonfly crawls out of its nymph exoskeleton , the exuvia , arching backwards when all but the tip of its abdomen is free, to allow its exoskeleton to harden. Curling back upwards, it completes its emergence, swallowing air, which plumps out its body, and pumping haemolymph into its wings, which causes them to expand to their full extent. Dragonflies in temperate areas can be categorized into two groups: an early group and

260-409: A branchial chamber, located around the fourth and fifth abdominal segments. These internal gills consist originally of six longitudinal folds, each side supported by cross-folds. But this system has been modified in several families. Water is pumped in and out of the abdomen through an opening at the tip. The naiads of some clubtails ( Gomphidae ) that burrow into the sediment, have a snorkel-like tube at

325-627: A group that included one of the largest insects that ever lived, Meganeuropsis permiana from the Early Permian , with a wingspan around 750 mm (30 in). The Protanisoptera , another ancestral group that lacks certain wing-vein characters found in modern Odonata, lived in the Permian . Anisoptera first appeared during the Toarcian age of the Early Jurassic , and the crown group developed in

390-501: A huge, extensible labium , armed with hooks and spines, which is used for catching prey. This labium is folded under the body at rest and struck out at great speed by hydraulic pressure created by the abdominal muscles. Both damselfly and dragonfly nymphs ventilate the rectum, but just some damselfly nymphs have a rectal epithelium that is rich in trachea , relying mostly on three feathery external gills as their major source of respiration. Only dragonfly nymphs have internal gills, called

455-567: A hydraulic function to expand the body between nymphal stages ( instars ) and to expand and stiffen the wings after the adult emerges from the final nymphal stage. The leading edge of each wing has a node where other veins join the marginal vein, and the wing is able to flex at this point. In most large species of dragonflies, the wings of females are shorter and broader than those of males. The legs are rarely used for walking, but are used to catch and hold prey, for perching, and for climbing on plants. Each has two short basal joints, two long joints, and

520-408: A later one. In any one area, individuals of a particular "spring species" emerge within a few days of each other. The springtime darner ( Basiaeschna janata ), for example, is suddenly very common in the spring, but disappears a few weeks later and is not seen again until the following year. By contrast, a "summer species" emerges over a period of weeks or months, later in the year. They may be seen on

585-522: A noniridescent blue that is produced structurally by scatter from arrays of tiny spheres in the endoplasmic reticulum of epidermal cells underneath the cuticle. The wings of dragonflies are generally clear, apart from the dark veins and pterostigmata. In the chasers (Libellulidae), however, many genera have areas of colour on the wings: for example, groundlings ( Brachythemis ) have brown bands on all four wings, while some scarlets ( Crocothemis ) and dropwings ( Trithemis ) have bright orange patches at

650-428: A packet of sperm from his primary genital opening on segment 9, near the end of his abdomen, to his secondary genitalia on segments 2–3, near the base of his abdomen. The male then grasps the female by the head with the claspers at the end of his abdomen; the structure of the claspers varies between species, and may help to prevent interspecific mating. The pair flies in tandem with the male in front, typically perching on

715-634: A problem that makes correlation between sections in different parts of the world difficult. If this biostratigraphical indicator is used, then technically the Lias Group —a lithostratigraphical division—spans the Jurassic / Triassic boundary. There are extensive Liassic outcrops around the coast of the United Kingdom , in particular in Glamorgan , North Yorkshire and Dorset . The 'Jurassic Coast' of Dorset

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780-494: A rigid, box-like structure with internal bracing, and provide a robust attachment for the powerful wing muscles inside. The thorax bears two pairs of wings and three pairs of legs. The wings are long, veined, and membranous, narrower at the tip and wider at the base. The hindwings are broader than the forewings and the venation is different at the base. The veins carry haemolymph , which is analogous to blood in vertebrates, and carries out many similar functions, but which also serves

845-416: A series of nymphal stages from which the adult emerges. Eggs laid inside plant tissues are usually shaped like grains of rice, while other eggs are the size of a pinhead, ellipsoidal, or nearly spherical. A clutch may have as many as 1500 eggs, and they take about a week to hatch into aquatic nymphs or naiads which moult between six and 15 times (depending on species) as they grow. Most of a dragonfly's life

910-475: A suitable substrate, but also the male hovering above her or continuing to clasp her and flying in tandem. This behaviour following the transfer of sperm is termed as mate guarding and the guarding male attempts to increase the probability of his sperm fertilising eggs. Sexual selection with sperm competition occurs within the spermatheca of the female and sperm can remain viable for at least 12 days in some species. Females can fertilise their eggs using sperm from

975-427: A sunlit stretch of shallow water, a special plant species, or the preferred substrate for egg-laying. The territory may be small or large, depending on its quality, the time of day, and the number of competitors, and may be held for a few minutes or several hours. Dragonflies including Tramea lacerata (black saddlebags) may notice landmarks that assist in defining the boundaries of the territory. Landmarks may reduce

1040-583: A territory against others of their own species, some against other species of dragonfly and a few against insects in unrelated groups. A particular perch may give a dragonfly a good view over an insect-rich feeding ground; males of many species such as the Pachydiplax longipennis (blue dasher) jostle other dragonflies to maintain the right to alight there. Defending a breeding territory is common among male dragonflies, especially in species that congregate around ponds. The territory contains desirable features such as

1105-438: A three-jointed foot, armed with a pair of claws. The long leg joints bear rows of spines, and in males, one row of spines on each front leg is modified to form an "eyebrush", for cleaning the surface of the compound eye. The abdomen is long and slender and consists of 10 segments. Three terminal appendages are on segment 10; a pair of superiors (claspers) and an inferior. The second and third segments are enlarged, and in males,

1170-538: A true clade ]   Libellulidae (skimmers) About 3,012 species of dragonflies were known in 2010; these are classified into 348 genera in 11 families . The distribution of diversity within the biogeographical regions are summarized below (the world numbers are not ordinary totals, as overlaps in species occur). Dragonflies live on every continent except Antarctica. In contrast to the damselflies (Zygoptera), which tend to have restricted distributions, some genera and species are spread across continents. For example,

1235-460: A twig or plant stem. The female then curls her abdomen downwards and forwards under her body to pick up the sperm from the male's secondary genitalia, while the male uses his "tail" claspers to grip the female behind the head: this distinctive posture is called the "heart" or "wheel"; the pair may also be described as being "in cop". Egg-laying (ovipositing) involves not only the female darting over floating or waterside vegetation to deposit eggs on

1300-452: Is also conflict between the males and females. Females may sometimes be harassed by males to the extent that it affects their normal activities including foraging and in some dimorphic species females have evolved multiple forms with some forms appearing deceptively like males. In some species females have evolved behavioural responses such as feigning death to escape the attention of males. Similarly, selection of habitat by adult dragonflies

1365-471: Is cosmopolitan, occurring on all continents in the warmer regions. Most Anisoptera species are tropical, with far fewer species in temperate regions. Some dragonflies, including libellulids and aeshnids, live in desert pools, for example in the Mojave Desert , where they are active in shade temperatures between 18 and 45 °C (64 and 113 °F); these insects were able to survive body temperatures above

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1430-416: Is not random, and terrestrial habitat patches may be held for up to 3 months. A species tightly linked to its birth site utilises a foraging area that is several orders of magnitude larger than the birth site. Mating in dragonflies is a complex, precisely choreographed process. First, the male has to attract a female to his territory, continually driving off rival males. When he is ready to mate, he transfers

1495-513: Is often associated with the pioneering work of Mary Anning of Lyme Regis . The facies of the Lower Jurassic in this area are predominantly of clays , thin limestones and siltstones , deposited under fully marine conditions. Lias Group strata form imposing cliffs on the Vale of Glamorgan coast, in southern Wales . Stretching for around 14 miles (23 km) between Cardiff and Porthcawl ,

1560-480: Is probably paraphyletic ). All these plesiosaurs had medium-sized necks and large heads. In the Toarcian , at the end of the Early Jurassic, the thalattosuchians (marine " crocodiles ") appeared, as did new genera of ichthyosaurs ( Stenopterygius , Eurhinosaurus , and the persistently primitive Suevoleviathan ) and plesiosaurs (the elasmosaurs (long-necked) Microcleidus and Occitanosaurus , and

1625-456: Is spent as a nymph, beneath the water's surface. The nymph extends its hinged labium (a toothed mouthpart similar to a lower mandible, which is sometimes termed as a "mask" as it is normally folded and held before the face) that can extend forward and retract rapidly to capture prey such as mosquito larvae, tadpoles , and small fish. They breathe through gills in their rectum , and can rapidly propel themselves by suddenly expelling water through

1690-554: The Early Jurassic . Dragonflies are represented in human culture on artefacts such as pottery, rock paintings, statues, and Art Nouveau jewellery. They are used in traditional medicine in Japan and China, and caught for food in Indonesia. They are symbols of courage, strength, and happiness in Japan, but seen as sinister in European folklore. Their bright colours and agile flight are admired in

1755-517: The Middle Jurassic . They retain some traits of their distant predecessors, and are in a group known as the Palaeoptera , meaning 'ancient-winged'. Like the gigantic griffinflies, dragonflies lack the ability to fold their wings up against their bodies in the way modern insects do, although some evolved their own different way to do so. The forerunners of modern Odonata are included in a clade called

1820-681: The infraorder Anisoptera below the order Odonata . About 3,000 extant species of dragonflies are known. Most are tropical , with fewer species in temperate regions . Loss of wetland habitat threatens dragonfly populations around the world. Adult dragonflies are characterised by a pair of large, multifaceted, compound eyes , two pairs of strong, transparent wings , sometimes with coloured patches, and an elongated body. Many dragonflies have brilliant iridescent or metallic colours produced by structural coloration , making them conspicuous in flight. An adult dragonfly's compound eyes have nearly 24,000 ommatidia each. Dragonflies can be mistaken for

1885-513: The pliosaur Hauffiosaurus ). On land, a number of new types of dinosaurs—the heterodontosaurids , scelidosaurs , stegosaurs , and tetanurans —appeared, and joined those groups like the coelophysoids , prosauropods and the sauropods that had continued over from the Triassic. Accompanying them as small carnivores were the sphenosuchian and protosuchid crocodilians. In the air, new types of pterosaurs replaced those that had died out at

1950-581: The Australian Petalura ingentissima , is by some measurements the largest of living dragonflies, having a wingspan of up to about 160 mm (6.3 in) and a body length of about 125 mm (4.9 in) ( Tetracanthagyna plagiata of another family can match or exceed its wingspan). Another large Australian species is Petalura gigantea , commonly known as the giant dragonfly. In the United States, two species are found, Tanypteryx hageni in

2015-544: The Gomphidae (clubtails) live in running water, and the Libellulidae (skimmers) live in still water. Some species live in temporary water pools and are capable of tolerating changes in water level, desiccation, and the resulting variations in temperature, but some genera such as Sympetrum (darters) have eggs and nymphs that can resist drought and are stimulated to grow rapidly in warm, shallow pools, also often benefiting from

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2080-1023: The Panodonata, which include the basal Zygoptera (damselflies) and the Anisoptera (true dragonflies). Today, some 3,000 species are extant around the world. The relationships of anisopteran families are not fully resolved as of 2021, but all the families are monophyletic except the Corduliidae , and the Austropetaliidae are sister to the Aeshnoidea :   Austropetaliidae   Aeshnoidea (hawkers)   Petaluridae (petaltails)   Gomphidae (clubtails)   Neopetaliidae   Cordulegastridae (goldenrings)   Chlorogomphidae   Synthemistidae (tigertails)   many Synthemistidae genera, incertae sedis   Macromiidae (cruisers)  " Corduliidae " (emeralds) [ not

2145-497: The absence of predators there. Vegetation and its characteristics including submerged, floating, emergent, or waterside are also important. Adults may require emergent or waterside plants to use as perches; others may need specific submerged or floating plants on which to lay eggs. Requirements may be highly specific, as in Aeshna viridis (green hawker), which lives in swamps with the water-soldier, Stratiotes aloides . The chemistry of

2210-689: The acidic Devonian and Carboniferous soils of the West Country ); the Cornish would pronounce the layers of limestone as ' laiyers ' or ' lias '; leac is Gaelic for "flat stone". There has been some debate over the actual base of the Hettangian Stage, and so of the Jurassic System itself. Biostratigraphically , the first appearance of psiloceratid ammonites has been used; but this depends on relatively complete ammonite faunas being present,

2275-478: The anus. Some naiads, such as the later stages of Antipodophlebia asthenes , hunt on land. The nymph stage of dragonflies lasts up to five years in large species, and between two months and three years in smaller species. When the naiad is ready to metamorphose into an adult, it stops feeding and makes its way to the surface, generally at night. It remains stationary with its head out of the water, while its respiration system adapts to breathing air, then climbs up

2340-453: The back of the head that grip structures on the front of the first thoracic segment. This arrester system is unique to the Odonata, and is activated when feeding and during tandem flight. The thorax consists of three segments as in all insects. The prothorax is small and flattened dorsally into a shield-like disc, which has two transverse ridges. The mesothorax and metathorax are fused into

2405-623: The blue-eyed darner Rhionaeschna multicolor lives all across North America, and in Central America; emperors Anax live throughout the Americas from as far north as Newfoundland to as far south as Bahia Blanca in Argentina, across Europe to central Asia, North Africa, and the Middle East. The globe skimmer Pantala flavescens is probably the most widespread dragonfly species in the world; it

2470-602: The closely related damselflies , which make up the other odonatan infraorder ( Zygoptera ) and are similar in body plan , though usually lighter in build; however, the wings of most dragonflies are held flat and away from the body, while damselflies hold their wings folded at rest, along or above the abdomen. Dragonflies are agile fliers, while damselflies have a weaker, fluttery flight. Dragonflies make use of motion camouflage when attacking prey or rivals. Dragonflies are predatory insects , both in their aquatic nymphal stage (also known as "naiads") and as adults. In some species,

2535-429: The costs of territory establishment, or might serve as a spatial reference. Some dragonflies signal ownership with striking colours on the face, abdomen, legs, or wings. The Plathemis lydia (common whitetail) dashes towards an intruder holding its white abdomen aloft like a flag. Other dragonflies engage in aerial dogfights or high-speed chases. A female must mate with the territory holder before laying her eggs. There

2600-426: The cuticle that reflect blue light. Greens often combine a structural blue with a yellow pigment. Freshly emerged adults, known as tenerals, are often pale, and obtain their typical colours after a few days. Some have their bodies covered with a pale blue, waxy powderiness called pruinosity; it wears off when scraped during mating, leaving darker areas. Some dragonflies, such as the green darner, Anax junius , have

2665-424: The eggs singly in each puncture they make. Dragonfly nymphs vary in form with species, and are loosely classed into claspers, sprawlers, hiders, and burrowers. The first instar is known as a prolarva, a relatively inactive stage from which it quickly moults into the more active nymphal form. The general body plan is similar to that of an adult, but the nymph lacks wings and reproductive organs. The lower jaw has

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2730-491: The end of the abdomen enabling them to draw in clean water while they are buried in mud. Naiads can forcefully expel a jet of water to propel themselves with great rapidity. Many adult dragonflies have brilliant iridescent or metallic colours produced by structural colouration , making them conspicuous in flight. Their overall coloration is often a combination of yellow, red, brown, and black pigments, with structural colours. Blues are typically created by microstructures in

2795-429: The female behind the head using a pair of claspers on the terminal segment. In females, the genital opening is on the underside of the eighth segment, and is covered by a simple flap (vulvar lamina) or an ovipositor , depending on species and the method of egg-laying. Dragonflies having simple flaps shed the eggs in water, mostly in flight. Dragonflies having ovipositors use them to puncture soft tissues of plants and place

2860-454: The female lays eggs by tapping the surface of the water repeatedly with her abdomen, by shaking the eggs out of her abdomen as she flies along, or by placing the eggs on vegetation. In a few species, the eggs are laid on emergent plants above the water, and development is delayed until these have withered and become immersed. Dragonflies are hemimetabolous insects; they do not have a pupal stage and undergo an incomplete metamorphosis with

2925-515: The flight muscles attached to the wing bases. Dragonflies have a high power/weight ratio, and have been documented accelerating at 4 G linearly and 9 G in sharp turns while pursuing prey. Early Jurassic Certain rocks of marine origin of this age in Europe are called " Lias " and that name was used for the period, as well, in 19th-century geology. In southern Germany rocks of this age are called Black Jurassic . There are two possible origins for

2990-515: The frontal hemisphere of the dragonfly. The compound eyes meet at the top of the head (except in the Petaluridae and Gomphidae, as also in the genus Epiophlebia ). Also, they have three simple eyes or ocelli. The mouthparts are adapted for biting with a toothed jaw; the flap-like labrum , at the front of the mouth, can be shot rapidly forward to catch prey . The head has a system for locking it in place that consists of muscles and small hairs on

3055-446: The gills of gravid freshwater mussels. Adults capture insect prey in the air, making use of their acute vision and highly controlled flight. The mating system of dragonflies is complex, and they are among the few insect groups that have a system of indirect sperm transfer along with sperm storage, delayed fertilisation, and sperm competition. Adult males vigorously defend territories near water; these areas provide suitable habitat for

3120-579: The head, thorax, and abdomen, as in all insects. It has a chitinous exoskeleton of hard plates held together with flexible membranes. The head is large with very short antennae . It is dominated by the two compound eyes, which cover most of its surface. The compound eyes are made up of ommatidia , the numbers being greater in the larger species. Aeshna interrupta has 22650 ommatidia of two varying sizes, 4500 being large. The facets facing downward tend to be smaller. Petalura gigantea has 23890 ommatidia of just one size. These facets provide complete vision in

3185-592: The male grasps the female at the back of the head, and the female curls her abdomen under her body to pick up sperm from the male's secondary genitalia at the front of his abdomen, forming the "heart" or "wheel" posture. Fossils of very large dragonfly-like insects, sometimes called griffinflies , are found from 325 million years ago (Mya) in Upper Carboniferous rocks; these had wingspans up to about 750 mm (30 in), though they were only distant relatives, not true dragonflies which first appeared during

3250-428: The male may help to pull her out of the water. Egg-laying takes two different forms depending on the species. The female in some families (Aeshnidae, Petaluridae) has a sharp-edged ovipositor with which she slits open a stem or leaf of a plant on or near the water, so she can push her eggs inside. In other families such as clubtails (Gomphidae), cruisers (Macromiidae), emeralds (Corduliidae), and skimmers (Libellulidae),

3315-439: The most northerly of all dragonflies. Dragonflies (suborder Anisoptera) are heavy-bodied, strong-flying insects that hold their wings horizontally both in flight and at rest. By contrast, damselflies (suborder Zygoptera) have slender bodies and fly more weakly; most species fold their wings over the abdomen when stationary, and the eyes are well separated on the sides of the head. An adult dragonfly has three distinct segments,

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3380-548: The name Lias: the first reason is it was taken by a geologist from an English quarryman 's dialect pronunciation of the word "layers"; secondly, sloops from north Cornish ports such as Bude would sail across the Bristol Channel to the Vale of Glamorgan to load up with rock from coastal limestone quarries (lias and Carboniferous limestone from South Wales was used throughout North Devon/North Cornwall as it contains calcium carbonate to 'sweeten' (i.e.neutralise)

3445-482: The nymphal stage lasts up to five years, and the adult stage may be as long as 10 weeks, but most species have an adult lifespan in the order of five weeks or less, and some survive for only a few days. They are fast, agile fliers capable of highly accurate aerial ambush, sometimes migrating across oceans, and often live near water. They have a uniquely complex mode of reproduction involving indirect insemination, delayed fertilisation, and sperm competition . During mating,

3510-403: The nymphs to develop, and for females to lay their eggs. Swarms of feeding adults aggregate to prey on swarming prey such as emerging flying ants or termites. Dragonflies as a group occupy a considerable variety of habitats, but many species, and some families, have their own specific environmental requirements. Some species prefer flowing waters, while others prefer standing water. For example,

3575-468: The poetry of Lord Tennyson and the prose of H. E. Bates . The infraorder Anisoptera comes from Greek ἄνισος anisos "unequal" and πτερόν pteron "wing" because dragonflies' hindwings are broader than their forewings . Dragonflies and their relatives are similar in structure to an ancient group, the Meganisoptera or griffinflies, from the 325  Mya Upper Carboniferous of Europe,

3640-612: The remarkable layers of these cliffs, situated on the Bristol Channel are a rhythmic decimetre scale repetition of limestone and mudstone formed as a late Triassic desert was inundated by the sea. During this period, ammonoids , which had almost died out at the end-of-Triassic extinction, radiated out into a huge diversity of new forms with complex suture patterns (the ammonites proper). Ammonites evolved so rapidly, and their shells are so often preserved, that they serve as important zone fossils . There were several distinct waves of ammonite evolution in Europe alone. The Early Jurassic

3705-411: The spermatheca at any time. Males use their penis and associated genital structures to compress or scrape out sperm from previous matings; this activity takes up much of the time that a copulating pair remains in the heart posture. Flying in tandem has the advantage that less effort is needed by the female for flight and more can be expended on egg-laying, and when the female submerges to deposit eggs,

3770-472: The thermal death point of insects of the same species in cooler places. Dragonflies live from sea level up to the mountains, decreasing in species diversity with altitude. Their altitudinal limit is about 3700 m, represented by a species of Aeshna in the Pamirs . Dragonflies become scarce at higher latitudes. They are not native to Iceland , but individuals are occasionally swept in by strong winds, including

3835-403: The underside of the second segment has a cleft, forming the secondary genitalia consisting of the lamina , hamule, genital lobe, and penis. There are remarkable variations in the presence and the form of the penis and the related structures, the flagellum , cornua, and genital lobes. Sperm is produced at the 9th segment, and is transferred to the secondary genitalia prior to mating. The male holds

3900-561: The water, including its trophic status (degree of enrichment with nutrients) and pH can also affect its use by dragonflies. Most species need moderate conditions, not too eutrophic , not too acidic; a few species such as Sympetrum danae (black darter) and Libellula quadrimaculata (four-spotted chaser) prefer acidic waters such as peat bogs, while others such as Libellula fulva (scarce chaser) need slow-moving, eutrophic waters with reeds or similar waterside plants. Many dragonflies, particularly males, are territorial . Some defend

3965-404: The west and Tachopteryx thoreyi in the east. The larvae live primarily in stream banks, mostly in burrows, but the larvae of the eastern US species, Tachopteryx thoreyi , the gray petaltail, live in depressions under wet leaves. The semiaquatic habitat of the larvae makes the petaltails unique in the modern dragonfly families. Dragonfly A dragonfly is a flying insect belonging to

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4030-575: The wetlands to lay their eggs or to find mating partners. Unwanted mating is energetically costly for females because it affects the amount of time that they are able to spend foraging. Dragonflies are powerful and agile fliers, capable of migrating across the sea, moving in any direction, and changing direction suddenly. In flight, the adult dragonfly can propel itself in six directions: upward, downward, forward, backward, to left and to right. They have four different styles of flight. The wings are powered directly , unlike most families of insects, with

4095-492: The wing bases. Some aeshnids such as the brown hawker ( Aeshna grandis ) have translucent, pale yellow wings. Dragonfly nymphs are usually a well- camouflaged blend of dull brown, green, and grey. Dragonflies and damselflies are predatory both in the aquatic nymphal and adult stages. Nymphs feed on a range of freshwater invertebrates and larger ones can prey on tadpoles and small fish . Naiads of one species, Phanogomphus militaris , may even act as parasites, feeding on

4160-652: The wing for several months, but this may represent a whole series of individuals, with new adults hatching out as earlier ones complete their lifespans. The sex ratio of male to female dragonflies varies both temporally and spatially. Adult dragonflies have a high male-biased ratio at breeding habitats. The male-bias ratio has contributed partially to the females using different habitats to avoid male harassment. As seen in Hine's emerald dragonfly ( Somatochlora hineana ), male populations use wetland habitats, while females use dry meadows and marginal breeding habitats, only migrating to

4225-476: Was an important time in the evolution of the marine reptiles. The Hettangian saw the already existing Rhaetian ichthyosaurs and plesiosaurs continuing to flourish, while at the same time a number of new types of these marine reptiles appeared, such as Ichthyosaurus and Temnodontosaurus among the ichthyosaurs, and Eurycleidus , Macroplata , and Rhomaleosaurus among the plesiosaurs (all Rhomaleosauridae , although as currently defined this group

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