Amblypygid
Encyclopedia
Amblypygi is an order
of invertebrate
animal
s belonging to the class Arachnid
a, in the subphylum
Chelicerata
of the phylum
Arthropod
a. They form a separate order of arachnids alongside the spider
s, scorpion
s and others.
Amblypygids are also known as whip spiders and tailless whip scorpions (not to be confused with whip scorpions that belong to the Arachnid order Thelyphonida). The name "amblypygid" means "blunt rump", a reference to a lack of the telson
("tail") carried by related species. Despite an offputting appearance, they are totally harmless to humans.
By 2003, 5 families, 17 genera and around 155 species had been discovered. They are found in tropical
and subtropical
regions worldwide. Some species are subterranean; many are nocturnal. During the day, they may hide under logs, bark, stones, or leaves. They prefer a humid environment.
Amblypygids may be up to 30cm long. Their bodies are broad and highly flattened, with a solid carapace and a segmented abdomen
. They have a pair of median eyes at the front of the carapace, and three smaller eyes placed further back on each side. The pedipalp
s are large and somewhat pincer-like, being adapted for grabbing prey.
As in some other arachnid orders, the first pair of legs are modified to act as sensory organs, while the animal uses the other six legs for walking. The sensory legs are very thin, have numerous sensory receptors, and can extend several times the length of body. Typically, the animal holds one of these legs out in front of it as it moves, and uses the other to probe the terrain to the side. Amblypygids have no silk
glands or venom
ous fangs.
s, then masticated with chelicerae
.
Courting rituals involve the male depositing stalked spermatophore
s, which have one or more sperm masses at the tip, onto the ground, and using his pedipalps to guide the female over them. She gathers the sperm and lays fertilized eggs
into a sac carried under the abdomen
. When the young hatch, they climb up onto the mother's back; any which fall off before their first moult will be eaten by the mother.
Amblypygids, particularly the species Phrynus marginemaculatus and Damon diadema, are thought to be among the few examples of arachnids which show signs of social behavior. Research conducted by entomologists at Cornell University
suggests that mother amblypygids communicate with their young by caressing the offspring with her anteniform front legs, and that the offspring reciprocate both with their mother and their siblings. Further, in an experiment where two or more siblings were placed in an unfamiliar environment, such as a different cage, they would seek each other out and gather back into a group.
ized amblypygids have been found dating back to the Carboniferous period
, for example Graeophonus
.
The following genera are recognised:
Charinidae
Weygoldt, 1996
Charontidae Simon, 1892
Phrynichidae Simon, 1900
Phrynidae Blanchard, 1852
Paracharontidae Weygoldt, 1996
incertae sedis
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...
of invertebrate
Invertebrate
An invertebrate is an animal without a backbone. The group includes 97% of all animal species – all animals except those in the chordate subphylum Vertebrata .Invertebrates form a paraphyletic group...
animal
Animal
Animals are a major group of multicellular, eukaryotic organisms of the kingdom Animalia or Metazoa. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later on in their life. Most animals are motile, meaning they can move spontaneously and...
s belonging to the class Arachnid
Arachnid
Arachnids are a class of joint-legged invertebrate animals in the subphylum Chelicerata. All arachnids have eight legs, although in some species the front pair may convert to a sensory function. The term is derived from the Greek words , meaning "spider".Almost all extant arachnids are terrestrial...
a, in the subphylum
Subphylum
In life, a subphylum is a taxonomic rank intermediate between phylum and superclass. The rank of subdivision in plants and fungi is equivalent to subphylum.Not all phyla are divided into subphyla...
Chelicerata
Chelicerata
The subphylum Chelicerata constitutes one of the major subdivisions of the phylum Arthropoda, and includes horseshoe crabs, scorpions, spiders and mites...
of the phylum
Phylum
In biology, a phylum The term was coined by Georges Cuvier from Greek φῦλον phylon, "race, stock," related to φυλή phyle, "tribe, clan." is a taxonomic rank below kingdom and above class. "Phylum" is equivalent to the botanical term division....
Arthropod
Arthropod
An arthropod is an invertebrate animal having an exoskeleton , a segmented body, and jointed appendages. Arthropods are members of the phylum Arthropoda , and include the insects, arachnids, crustaceans, and others...
a. They form a separate order of arachnids alongside the spider
Spider
Spiders are air-breathing arthropods that have eight legs, and chelicerae with fangs that inject venom. They are the largest order of arachnids and rank seventh in total species diversity among all other groups of organisms...
s, scorpion
Scorpion
Scorpions are predatory arthropod animals of the order Scorpiones within the class Arachnida. They have eight legs and are easily recognized by the pair of grasping claws and the narrow, segmented tail, often carried in a characteristic forward curve over the back, ending with a venomous stinger...
s and others.
Amblypygids are also known as whip spiders and tailless whip scorpions (not to be confused with whip scorpions that belong to the Arachnid order Thelyphonida). The name "amblypygid" means "blunt rump", a reference to a lack of the 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...
("tail") carried by related species. Despite an offputting appearance, they are totally harmless to humans.
By 2003, 5 families, 17 genera and around 155 species had been discovered. They are found in tropical
Tropics
The tropics is a region of the Earth surrounding the Equator. It is limited in latitude by the Tropic of Cancer in the northern hemisphere at approximately N and the Tropic of Capricorn in the southern hemisphere at S; these latitudes correspond to the axial tilt of the Earth...
and subtropical
Subtropics
The subtropics are the geographical and climatical zone of the Earth immediately north and south of the tropical zone, which is bounded by the Tropic of Cancer and the Tropic of Capricorn, at latitudes 23.5°N and 23.5°S...
regions worldwide. Some species are subterranean; many are nocturnal. During the day, they may hide under logs, bark, stones, or leaves. They prefer a humid environment.
Physical description
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...
. They have a pair of median eyes at the front of the carapace, and three smaller eyes placed further back on each side. The pedipalp
Pedipalp
Pedipalps , are the second pair of appendages of the prosoma in the subphylum Chelicerata. They are traditionally thought to be homologous with mandibles in Crustacea and insects, although more recent studies Pedipalps (commonly shortened to palps or palpi), are the second pair of appendages of the...
s are large and somewhat pincer-like, being adapted for grabbing prey.
As in some other arachnid orders, the first pair of legs are modified to act as sensory organs, while the animal uses the other six legs for walking. The sensory legs are very thin, have numerous sensory receptors, and can extend several times the length of body. Typically, the animal holds one of these legs out in front of it as it moves, and uses the other to probe the terrain to the side. Amblypygids have no silk
Silk
Silk is a natural protein fiber, some forms of which can be woven into textiles. The best-known type of silk is obtained from the cocoons of the larvae of the mulberry silkworm Bombyx mori reared in captivity...
glands or venom
Venom
Venom is the general term referring to any variety of toxins used by certain types of animals that inject it into their victims by the means of a bite or a sting...
ous fangs.
Behaviour
Amblypygids often move about sideways on their six walking legs, with one "whip" pointed in the direction of travel while the other probes their other sides. Prey are located with these "whips", captured with pedipalpPedipalp
Pedipalps , are the second pair of appendages of the prosoma in the subphylum Chelicerata. They are traditionally thought to be homologous with mandibles in Crustacea and insects, although more recent studies Pedipalps (commonly shortened to palps or palpi), are the second pair of appendages of the...
s, then masticated with chelicerae
Chelicerae
The chelicerae are mouthparts of the Chelicerata, an arthropod subphylum that includes arachnids, Merostomata , and Pycnogonida . Chelicerae are pointed appendages which are used to grasp food, and are found in place of the chewing mandibles most other arthropods have...
.
Courting rituals involve the male depositing stalked spermatophore
Spermatophore
A spermatophore or sperm ampulla is a capsule or mass created by males of various animal species, containing spermatozoa and transferred in entirety to the female's ovipore during copulation...
s, which have one or more sperm masses at the tip, onto the ground, and using his pedipalps to guide the female over them. She gathers the sperm and lays fertilized 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...
into a sac carried under 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...
. When the young hatch, they climb up onto the mother's back; any which fall off before their first moult will be eaten by the mother.
Amblypygids, particularly the species Phrynus marginemaculatus and Damon diadema, are thought to be among the few examples of arachnids which show signs of social behavior. Research conducted by entomologists at Cornell University
Cornell University
Cornell University is an Ivy League university located in Ithaca, New York, United States. It is a private land-grant university, receiving annual funding from the State of New York for certain educational missions...
suggests that mother amblypygids communicate with their young by caressing the offspring with her anteniform front legs, and that the offspring reciprocate both with their mother and their siblings. Further, in an experiment where two or more siblings were placed in an unfamiliar environment, such as a different cage, they would seek each other out and gather back into a group.
History
FossilFossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
ized amblypygids have been found dating back to the Carboniferous period
Carboniferous
The Carboniferous is a geologic period and system that extends from the end of the Devonian Period, about 359.2 ± 2.5 Mya , to the beginning of the Permian Period, about 299.0 ± 0.8 Mya . The name is derived from the Latin word for coal, carbo. Carboniferous means "coal-bearing"...
, for example Graeophonus
Graeophonus
Graeophonus is an extinct genus of tailless whip scorpion described from three species found in the Carboniferous fossil record. The genus is known from two, or possibly three, species described from North America and England...
.
Genera
Charinidae
Charinidae
Charinidae is an arachnid family within the order of tailless whip scorpions. It is the largest family within the Amblypygi: 39 species are described, within three genera...
Weygoldt, 1996
- Catageus Thorell, 1889 (1 species)
- Charinus Simon, 1892 (33 species)
- Sarax Simon, 1892 (10 species)
Charontidae Simon, 1892
- Charon Karsch, 1879 (5 species)
- Stygophrynus Kraepelin, 1895 (7 species)
Phrynichidae Simon, 1900
- Damon C. L. Koch, 1850 (10 species)
- Musicodamon Fage, 1939 (1 species)
- Phrynichodamon Weygoldt, 1996 (1 species)
- Euphrynichus Weygoldt, 1995 (2 species)
- Phrynichus Karsch, 1879 (16 species)
- Trichodamon Mello-Leitão, 1935 (2 species)
- Xerophrynus Weygoldt, 1996 (1 species)
Phrynidae Blanchard, 1852
- Heterophrynus Pocock, 1894 (14 species)
- Acanthophrynus Kraepelin, 1899 (1 species)
- †Electrophrynus Patrunkevich, 1971 (1 species; Late Oligocene – Early Miocene)
- Paraphrynus Moreno, 1940 (18 species)
- Phrynus Lamarck, 1801 (28 species, Oligocene - Recent)
Paracharontidae Weygoldt, 1996
- †GraeophonusGraeophonusGraeophonus is an extinct genus of tailless whip scorpion described from three species found in the Carboniferous fossil record. The genus is known from two, or possibly three, species described from North America and England...
Scudder, 1890 (2-3 species, Carboniferous) - Paracharon Hansen, 1921 (1 species)
incertae sedis
Incertae sedis
, is a term used to define a taxonomic group where its broader relationships are unknown or undefined. Uncertainty at specific taxonomic levels is attributed by , , and similar terms.-Examples:*The fossil plant Paradinandra suecica could not be assigned to any...
- † Sorellophrynus Harvey, 2002 (1 species, Upper Carboniferous)
- † Thelyphrynus Petrunkevich, 1913 (1 species, Upper Carboniferous)
External links
- Picture of a Mexican amblypygid (referred to as a "tailless whip scorpion") and its habitat
- Amblypigid video summarizing research from University of Nebraska's Eben Gering.
- NPR Science Friday show that makes mention
- Amblypygi. The Antillean (West Indian) fauna.