Chirocephalus diaphanus
Encyclopedia
Chirocephalus diaphanus is a widely distributed Europe
an species
of fairy shrimp
that lives as far north as Great Britain
, where it is the only surviving species of fairy shrimp and is protected under the Wildlife and Countryside Act 1981
. It is a translucent animal, about 0.5 in (1.3 cm) long, with reddened tips to the abdomen
and appendage
s. The body comprises a head, a thorax bearing 11 pairs of appendage
s, and a seven-segmented abdomen. In males, the antennae
are enlarged to form "frontal appendages", while females have an egg pouch at the end of the thorax.
The life cycle
of C. diaphanus is extremely fast, and the species can only persist in pools without predators. The eggs
tolerate drying out
, and hatch when re-immersed in water. C. diaphanus was first reported in the scientific literature in 1704, but was only separated from other species and given its scientific name in 1803. The specific epithet diaphanus refers to the animal's transparency.
The body becomes wider towards the head, which has a conspicuous mandibular groove. It also bears a pair of stalked compound eyes, as well as a sessile median eye, two pairs of antennae
, and the mouthparts. The mouthparts comprise a labrum, directed backwards over the mouth and pairs of mandibles
, paragnatha, maxillules and vestigial maxillae.
The thorax
is made up of twelve body segments, the last of which is fused to the first segment of the abdomen. There is no carapace
, but each of the eleven free segments bears a pair of phyllopodia, which have a series of bristles pointing along the animal's midline. The abdomen consists of seven segments without appendages, and a slender telson
which bears a pair of caudal rami.
Males and females can be recognised by a suite of sexually dimorphic
characters. While the antennae of females are triangular and relatively short, males' antennae are long and jointed, and each one bears a complex "frontal appendage", which is used to clasp the female during mating. The last somite
of the thorax
is fused with the first somite of the abdomen
. In males, it bears a pair of processes, the extensions of the vasa deferentia
in a protrusible penis. In females, there is a single egg pouch, which is also thought to derive from a pair of appendage
s.
species, which reaches its north-western limit in Great Britain
, and is missing from Fennoscandia
. Its distribution in Western Europe
extends almost continuously from Great Britain to the Iberian Peninsula
, and as far east as the Rhine in Germany. A single occurrence of C. diaphanus is known from the Benelux
countries, in pools in South Limburg, Netherlands
. Further east, it occurs south of 47°N
in the Apennine and Balkan
peninsulas, reaching the Black Sea
in Romania
; an isolated population exists at the mouth of the Vistula
river in Poland
. In the Mediterranean Sea
, populations exist on Sicily
and Crete
.
C. diaphanus is the only species of fairy shrimp
to occur naturally in Great Britain; Tanymastix stagnalis
is found in western Ireland, and Artemia salina
formerly occurred in England. Within Great Britain, C. diaphanus is restricted to areas with a deficit of precipitation
against evapotranspiration
between April and September. This means that it is only found frequently in southern England, with scattered records as far north as Yorkshire
.
s to muddy ruts, preferring sites with regular disturbance, such as passing tractor
s or livestock
. It has a broad range of ecological tolerances, in terms of temperature, dissolved oxygen and pH
, but cannot coexist with predatory fish. C. diaphanus swims with its ventral side upwards, and is a filter feeder
, collecting zooplankton
and detritus
with its phyllopodia.
The life cycle
of Chirocephalus diaphanus is extremely fast. The typical duration of a full life cycle is not known, but a figure of around 3 months has been suggested. The eggs are tolerant to drying out
; when their habitat fills with water again, some of the eggs will hatch, while others remain dormant. This enables the species to continue to survive in an unpredictable habitat, since some eggs remain in case the habitat does not persist for long enough for the animals to mate and produce offspring. Dispersal between bodies of water can occur through the movements of animals such as cattle, deer and horses.
in some parts of its range. In Germany, it is included on the Red List of endangered species. In the United Kingdom
, C. diaphanus is protected under Schedule 5 of the Wildlife and Countryside Act 1981
, and it is listed as a "Species of Conservation Concern" under the United Kingdom Biodiversity Action Plan
. The main threat to its survival are changes in land use: its habitats are often considered unsightly, and the temporary pools it inhabits are frequently filled in or converted into permanent ponds.
was a sketch by James Petiver
in a 1704 volume of his Gazophylacii Naturae, where he named it ("tiny freshwater Squilla, swimming on its back"). There was much confusion between species in the early literature, and it is often unclear what species early authors were referring to. Carl Linnaeus, having described a fairy shrimp as a possible insect
larva
in Fauna Suecica, described it among the crustaceans in the 10th edition of his Systema Naturae
in 1758, under the name "Cancer stagnalis" (now Tanymastix stagnalis
). That name was also used by later authors, but sometimes referring to other species.
The situation was clarified by Bénédict Prévost in 1803, when he published a detailed description of Chirocephalus diaphanus, including mention of the frontal appendages which distinguish it from other fairy shrimp such as Tanymastix stagnalis. Prévost's work was originally published in the in 1803, and was reprinted by Louis Jurine
as an appendix to his 1820 .
The name Chirocephalus derives from the Greek
roots (, "hand"), and (cephalon, "head"). The specific epithet derives from the Greek , meaning "diaphanous" or transparent
. Prévost later regretted the epithet, arguing that several other species were just as transparent as the one he had described. The common name
"fairy shrimp" comes from the animal's delicate appearance, and the "iridescent
gleaming of the bristles on its appendages".
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
an species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of fairy shrimp
Fairy shrimp
Anostraca is one of the four orders of crustaceans in the class Branchiopoda; its members are also known as fairy shrimp. They are usually long . Most species have 20 body segments, bearing 11 pairs of leaf-like phyllopodia , and the body lacks a carapace...
that lives as far north as Great Britain
Great Britain
Great Britain or Britain is an island situated to the northwest of Continental Europe. It is the ninth largest island in the world, and the largest European island, as well as the largest of the British Isles...
, where it is the only surviving species of fairy shrimp and is protected under the Wildlife and Countryside Act 1981
Wildlife and Countryside Act 1981
The Wildlife and Countryside Act 1981 is an Act of Parliament in the United Kingdom and was implemented to comply with the Directive 2009/147/EC on the conservation of wild birds...
. It is a translucent animal, about 0.5 in (1.3 cm) long, with reddened tips to the abdomen
Abdomen
In vertebrates such as mammals the abdomen constitutes the part of the body between the thorax and pelvis. The region enclosed by the abdomen is termed the abdominal cavity...
and appendage
Appendage
In invertebrate biology, an appendage is an external body part, or natural prolongation, that protrudes from an organism's body . It is a general term that covers any of the homologous body parts that may extend from a body segment...
s. The body comprises a head, a thorax bearing 11 pairs of appendage
Appendage
In invertebrate biology, an appendage is an external body part, or natural prolongation, that protrudes from an organism's body . It is a general term that covers any of the homologous body parts that may extend from a body segment...
s, and a seven-segmented abdomen. In males, the antennae
Antenna (biology)
Antennae in biology have historically been paired appendages used for sensing in arthropods. More recently, the term has also been applied to cilium structures present in most cell types of eukaryotes....
are enlarged to form "frontal appendages", while females have an egg pouch at the end of the thorax.
The life cycle
Biological life cycle
A life cycle is a period involving all different generations of a species succeeding each other through means of reproduction, whether through asexual reproduction or sexual reproduction...
of C. diaphanus is extremely fast, and the species can only persist in pools without predators. The eggs
Egg (biology)
An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...
tolerate drying out
Desiccation tolerance
Desiccation tolerance refers to the ability of an organism to withstand or endure extreme dryness, or drought-like conditions. Plants and animals living in arid or periodically arid environments such as temporary streams or ponds may face the challenge of desiccation, therefore physiological or...
, and hatch when re-immersed in water. C. diaphanus was first reported in the scientific literature in 1704, but was only separated from other species and given its scientific name in 1803. The specific epithet diaphanus refers to the animal's transparency.
Description
Chirocephalus diaphanus is a "beautiful, translucent crustacean". Its body is subcylindrical, and around 0.5 inches (1.3 cm) long, mostly transparent, but with black eyes, and red tips to the appendages and abdomen.The body becomes wider towards the head, which has a conspicuous mandibular groove. It also bears a pair of stalked compound eyes, as well as a sessile median eye, two pairs of antennae
Antenna (biology)
Antennae in biology have historically been paired appendages used for sensing in arthropods. More recently, the term has also been applied to cilium structures present in most cell types of eukaryotes....
, and the mouthparts. The mouthparts comprise a labrum, directed backwards over the mouth and pairs of mandibles
Mandible (arthropod)
thumb|250px|The mandibles of a [[Bull ant]]The mandible of an arthropod is either of a pair of mouthparts used for biting, cutting and holding food. Mandibles are often simply referred to as jaws. Mandibles are present in the extant subphyla Myriapoda , Crustacea and Hexapoda...
, paragnatha, maxillules and vestigial maxillae.
The thorax
Thorax
The thorax is a division of an animal's body that lies between the head and the abdomen.-In tetrapods:...
is made up of twelve body segments, the last of which is fused to the first segment of the abdomen. There is no carapace
Carapace
A carapace is a dorsal section of the exoskeleton or shell in a number of animal groups, including arthropods such as crustaceans and arachnids, as well as vertebrates such as turtles and tortoises. In turtles and tortoises, the underside is called the plastron.-Crustaceans:In crustaceans, the...
, but each of the eleven free segments bears a pair of phyllopodia, which have a series of bristles pointing along the animal's midline. The abdomen consists of seven segments without appendages, and a slender telson
Telson
The telson is the last division of the body of a crustacean. It is not considered a true segment because it does not arise in the embryo from teloblast areas as do real segments. It never carries any appendages, but a forked "tail" called the caudal furca is often present. Together with the...
which bears a pair of caudal rami.
Males and females can be recognised by a suite of sexually dimorphic
Sexual dimorphism
Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...
characters. While the antennae of females are triangular and relatively short, males' antennae are long and jointed, and each one bears a complex "frontal appendage", which is used to clasp the female during mating. The last somite
Somite
A somite is a division of the body of an animal. In vertebrates this is mainly discernible in the embryo stage; in arthropods it is a characteristic of a hypothetical ancestor.- In vertebrates :...
of the thorax
Thorax
The thorax is a division of an animal's body that lies between the head and the abdomen.-In tetrapods:...
is fused with the first somite of the abdomen
Abdomen
In vertebrates such as mammals the abdomen constitutes the part of the body between the thorax and pelvis. The region enclosed by the abdomen is termed the abdominal cavity...
. In males, it bears a pair of processes, the extensions of the vasa deferentia
Vas deferens
The vas deferens , also called ductus deferens, , is part of the male anatomy of many vertebrates; they transport sperm from the epididymis in anticipation of ejaculation....
in a protrusible penis. In females, there is a single egg pouch, which is also thought to derive from a pair of appendage
Appendage
In invertebrate biology, an appendage is an external body part, or natural prolongation, that protrudes from an organism's body . It is a general term that covers any of the homologous body parts that may extend from a body segment...
s.
Distribution
Chirocephalus diaphanus is a MediterraneanMediterranean Basin
In biogeography, the Mediterranean Basin refers to the lands around the Mediterranean Sea that have a Mediterranean climate, with mild, rainy winters and hot, dry summers, which supports characteristic Mediterranean forests, woodlands, and scrub vegetation...
species, which reaches its north-western limit in Great Britain
Great Britain
Great Britain or Britain is an island situated to the northwest of Continental Europe. It is the ninth largest island in the world, and the largest European island, as well as the largest of the British Isles...
, and is missing from Fennoscandia
Fennoscandia
Fennoscandia and Fenno-Scandinavia are geographic and geological terms used to describe the Scandinavian Peninsula, the Kola Peninsula, Karelia and Finland...
. Its distribution in Western Europe
Western Europe
Western Europe is a loose term for the collection of countries in the western most region of the European continents, though this definition is context-dependent and carries cultural and political connotations. One definition describes Western Europe as a geographic entity—the region lying in the...
extends almost continuously from Great Britain to the Iberian Peninsula
Iberian Peninsula
The Iberian Peninsula , sometimes called Iberia, is located in the extreme southwest of Europe and includes the modern-day sovereign states of Spain, Portugal and Andorra, as well as the British Overseas Territory of Gibraltar...
, and as far east as the Rhine in Germany. A single occurrence of C. diaphanus is known from the Benelux
Benelux
The Benelux is an economic union in Western Europe comprising three neighbouring countries, Belgium, the Netherlands, and Luxembourg. These countries are located in northwestern Europe between France and Germany...
countries, in pools in South Limburg, Netherlands
Netherlands
The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...
. Further east, it occurs south of 47°N
47th parallel north
The 47th parallel north is a circle of latitude that is 47 degrees north of the Earth's equatorial plane. It crosses Europe, Asia, the Pacific Ocean, North America, and the Atlantic Ocean....
in the Apennine and Balkan
Balkans
The Balkans is a geopolitical and cultural region of southeastern Europe...
peninsulas, reaching the Black Sea
Black Sea
The Black Sea is bounded by Europe, Anatolia and the Caucasus and is ultimately connected to the Atlantic Ocean via the Mediterranean and the Aegean seas and various straits. The Bosphorus strait connects it to the Sea of Marmara, and the strait of the Dardanelles connects that sea to the Aegean...
in Romania
Romania
Romania is a country located at the crossroads of Central and Southeastern Europe, on the Lower Danube, within and outside the Carpathian arch, bordering on the Black Sea...
; an isolated population exists at the mouth of the Vistula
Vistula
The Vistula is the longest and the most important river in Poland, at 1,047 km in length. The watershed area of the Vistula is , of which lies within Poland ....
river in Poland
Poland
Poland , officially the Republic of Poland , is a country in Central Europe bordered by Germany to the west; the Czech Republic and Slovakia to the south; Ukraine, Belarus and Lithuania to the east; and the Baltic Sea and Kaliningrad Oblast, a Russian exclave, to the north...
. In the Mediterranean Sea
Mediterranean Sea
The Mediterranean Sea is a sea connected to the Atlantic Ocean surrounded by the Mediterranean region and almost completely enclosed by land: on the north by Anatolia and Europe, on the south by North Africa, and on the east by the Levant...
, populations exist on Sicily
Sicily
Sicily is a region of Italy, and is the largest island in the Mediterranean Sea. Along with the surrounding minor islands, it constitutes an autonomous region of Italy, the Regione Autonoma Siciliana Sicily has a rich and unique culture, especially with regard to the arts, music, literature,...
and Crete
Crete
Crete is the largest and most populous of the Greek islands, the fifth largest island in the Mediterranean Sea, and one of the thirteen administrative regions of Greece. It forms a significant part of the economy and cultural heritage of Greece while retaining its own local cultural traits...
.
C. diaphanus is the only species of fairy shrimp
Fairy shrimp
Anostraca is one of the four orders of crustaceans in the class Branchiopoda; its members are also known as fairy shrimp. They are usually long . Most species have 20 body segments, bearing 11 pairs of leaf-like phyllopodia , and the body lacks a carapace...
to occur naturally in Great Britain; Tanymastix stagnalis
Tanymastix stagnalis
Tanymastix stagnalis is a species of Anostraca that lives in temporary pools across Europe. It may reach up to in some areas and has 11 pairs of bristly, flattened appendages. It swims upside-down and filters food particles from the water...
is found in western Ireland, and Artemia salina
Artemia salina
Artemia salina is a species of brine shrimp – aquatic crustaceans that are more closely related to Triops and cladocerans than to true shrimp. It is a very old species that does not appear to have changed in .-Description:...
formerly occurred in England. Within Great Britain, C. diaphanus is restricted to areas with a deficit of precipitation
Precipitation (meteorology)
In meteorology, precipitation In meteorology, precipitation In meteorology, precipitation (also known as one of the classes of hydrometeors, which are atmospheric water phenomena is any product of the condensation of atmospheric water vapor that falls under gravity. The main forms of precipitation...
against evapotranspiration
Evapotranspiration
Evapotranspiration is a term used to describe the sum of evaporation and plant transpiration from the Earth's land surface to atmosphere. Evaporation accounts for the movement of water to the air from sources such as the soil, canopy interception, and waterbodies...
between April and September. This means that it is only found frequently in southern England, with scattered records as far north as Yorkshire
Yorkshire
Yorkshire is a historic county of northern England and the largest in the United Kingdom. Because of its great size in comparison to other English counties, functions have been increasingly undertaken over time by its subdivisions, which have also been subject to periodic reform...
.
Ecology and life cycle
The fairy shrimp is found in temporary pools of water, from seasonal pondPond
A pond is a body of standing water, either natural or man-made, that is usually smaller than a lake. A wide variety of man-made bodies of water are classified as ponds, including water gardens, water features and koi ponds; all designed for aesthetic ornamentation as landscape or architectural...
s to muddy ruts, preferring sites with regular disturbance, such as passing tractor
Tractor
A tractor is a vehicle specifically designed to deliver a high tractive effort at slow speeds, for the purposes of hauling a trailer or machinery used in agriculture or construction...
s or livestock
Livestock
Livestock refers to one or more domesticated animals raised in an agricultural setting to produce commodities such as food, fiber and labor. The term "livestock" as used in this article does not include poultry or farmed fish; however the inclusion of these, especially poultry, within the meaning...
. It has a broad range of ecological tolerances, in terms of temperature, dissolved oxygen and pH
PH
In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...
, but cannot coexist with predatory fish. C. diaphanus swims with its ventral side upwards, and is a filter feeder
Filter feeder
Filter feeders are animals that feed by straining suspended matter and food particles from water, typically by passing the water over a specialized filtering structure. Some animals that use this method of feeding are clams, krill, sponges, baleen whales, and many fish and some sharks. Some birds,...
, collecting zooplankton
Zooplankton
Zooplankton are heterotrophic plankton. Plankton are organisms drifting in oceans, seas, and bodies of fresh water. The word "zooplankton" is derived from the Greek zoon , meaning "animal", and , meaning "wanderer" or "drifter"...
and detritus
Detritus
Detritus is a biological term used to describe dead or waste organic material.Detritus may also refer to:* Detritus , a geological term used to describe the particles of rock produced by weathering...
with its phyllopodia.
The life cycle
Biological life cycle
A life cycle is a period involving all different generations of a species succeeding each other through means of reproduction, whether through asexual reproduction or sexual reproduction...
of Chirocephalus diaphanus is extremely fast. The typical duration of a full life cycle is not known, but a figure of around 3 months has been suggested. The eggs are tolerant to drying out
Desiccation tolerance
Desiccation tolerance refers to the ability of an organism to withstand or endure extreme dryness, or drought-like conditions. Plants and animals living in arid or periodically arid environments such as temporary streams or ponds may face the challenge of desiccation, therefore physiological or...
; when their habitat fills with water again, some of the eggs will hatch, while others remain dormant. This enables the species to continue to survive in an unpredictable habitat, since some eggs remain in case the habitat does not persist for long enough for the animals to mate and produce offspring. Dispersal between bodies of water can occur through the movements of animals such as cattle, deer and horses.
Conservation status
Chirocephalus diaphanus is subject to protection under environmental lawEnvironmental law
Environmental law is a complex and interlocking body of treaties, conventions, statutes, regulations, and common law that operates to regulate the interaction of humanity and the natural environment, toward the purpose of reducing the impacts of human activity...
in some parts of its range. In Germany, it is included on the Red List of endangered species. In the United Kingdom
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
, C. diaphanus is protected under Schedule 5 of the Wildlife and Countryside Act 1981
Wildlife and Countryside Act 1981
The Wildlife and Countryside Act 1981 is an Act of Parliament in the United Kingdom and was implemented to comply with the Directive 2009/147/EC on the conservation of wild birds...
, and it is listed as a "Species of Conservation Concern" under the United Kingdom Biodiversity Action Plan
United Kingdom Biodiversity Action Plan
The United Kingdom Biodiversity Action Plan is the governmental response to the Convention on Biological Diversity signed in 1992. When the Biodiversity Action Plans were first published in 1994, the conservation of 391 species and 45 habitats was covered. 1,150 species and 65 habitats are...
. The main threat to its survival are changes in land use: its habitats are often considered unsightly, and the temporary pools it inhabits are frequently filled in or converted into permanent ponds.
Taxonomic history
The first mention of any Chirocephalus species in the scientific literatureScientific literature
Scientific literature comprises scientific publications that report original empirical and theoretical work in the natural and social sciences, and within a scientific field is often abbreviated as the literature. Academic publishing is the process of placing the results of one's research into the...
was a sketch by James Petiver
James Petiver
James Petiver was a London apothecary, a Fellow of the Royal Society as well as London's informal Temple Coffee House Botany Club, famous for his study of botany and entomology.-Life:...
in a 1704 volume of his Gazophylacii Naturae, where he named it ("tiny freshwater Squilla, swimming on its back"). There was much confusion between species in the early literature, and it is often unclear what species early authors were referring to. Carl Linnaeus, having described a fairy shrimp as a possible insect
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...
larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...
in Fauna Suecica, described it among the crustaceans in the 10th edition of his Systema Naturae
Systema Naturae
The book was one of the major works of the Swedish botanist, zoologist and physician Carolus Linnaeus. The first edition was published in 1735...
in 1758, under the name "Cancer stagnalis" (now Tanymastix stagnalis
Tanymastix stagnalis
Tanymastix stagnalis is a species of Anostraca that lives in temporary pools across Europe. It may reach up to in some areas and has 11 pairs of bristly, flattened appendages. It swims upside-down and filters food particles from the water...
). That name was also used by later authors, but sometimes referring to other species.
The situation was clarified by Bénédict Prévost in 1803, when he published a detailed description of Chirocephalus diaphanus, including mention of the frontal appendages which distinguish it from other fairy shrimp such as Tanymastix stagnalis. Prévost's work was originally published in the in 1803, and was reprinted by Louis Jurine
Louis Jurine
Louis Jurine was a Swiss physician, surgeon and naturalist mainly interested in entomology. He lived in Geneva.-Surgeon:Studies of surgery in Paris. Jurine quickly acquires a very great reputation of expert, well beyond Geneva...
as an appendix to his 1820 .
The name Chirocephalus derives from the Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...
roots (, "hand"), and (cephalon, "head"). The specific epithet derives from the Greek , meaning "diaphanous" or transparent
Transparency and translucency
In the field of optics, transparency is the physical property of allowing light to pass through a material; translucency only allows light to pass through diffusely. The opposite property is opacity...
. Prévost later regretted the epithet, arguing that several other species were just as transparent as the one he had described. The common name
Common name
A common name of a taxon or organism is a name in general use within a community; it is often contrasted with the scientific name for the same organism...
"fairy shrimp" comes from the animal's delicate appearance, and the "iridescent
Iridescence
Iridescence is generally known as the property of certain surfaces which appear to change color as the angle of view or the angle of illumination changes...
gleaming of the bristles on its appendages".