Menemerus Bifurcus
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''Menemerus bifurcus'' 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), ...
of
jumping spider Jumping spiders are a group of spiders that constitute the family (biology), family Salticidae. , this family contained over 600 species description, described genus, genera and over 6,000 described species, making it the largest family of spide ...
in the
genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...
''
Menemerus ''Menemerus'' is a genus of Salticidae, jumping spiders that was first described by Eugène Simon, Eugène Louis Simon in 1868. They are long, flattened in shape, and very hairy, usually with brown and grayish hairs. Most species have white edges ...
'' that lives in South Africa, Zambia and Zimbabwe. The species was first described in 1999 by
Wanda Wesołowska Wanda Wesołowska (born 11 August 1950) is a Polish zoologist known for her work with jumping spiders. She has described more species of jumping spider than any contemporary writer, and is second only to Eugène Simon in the history of arachnolo ...
, one of over 500 descriptions she has written during her lifetime. The spider lives in groups in ''
Acacia ''Acacia'', commonly known as wattles or acacias, is a genus of about of shrubs and trees in the subfamily Mimosoideae of the pea family Fabaceae. Initially, it comprised a group of plant species native to Africa, South America, and Austral ...
'', ''
Combretum ''Combretum'', the bushwillows or combretums, make up the type genus of the family Combretaceae. The genus comprises about 272 species of trees and shrubs, most of which are native to Tropics, tropical and southern Africa, about 5 to Madagascar ...
'', ''
Jacaranda ''Jacaranda'' is a genus of 49 species of flowering plants in the family Bignoniaceae, native to tropical and subtropical regions of the Americas while cultivated around the world. The generic name is also used as the common name. The species ' ...
'', ''
Spathodea ''Spathodea'' is a genus in the plant family Bignoniaceae. The single species it contains, ''Spathodea campanulata'', is commonly known as the African tulip tree. The tree grows between tall and is native to tropical dry forests of Africa. It h ...
'' and ''
Trichilia ''Trichilia'' is a flowering plant genus in the family (biology), family Meliaceae. These plants are particularly diverse in sub-Saharan Africa and tropical South America. Several species are used in folk medicine and shamanism – e.g. ''Tr ...
'' trees as well as in houses and other areas of human habitation. It descends to attack prey on long threads of silk. It is a small spider, with a
carapace A carapace is a dorsal (upper) 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 unde ...
that is between long and an
abdomen The abdomen (colloquially called the gut, belly, tummy, midriff, tucky, or stomach) is the front part of the torso between the thorax (chest) and pelvis in humans and in other vertebrates. The area occupied by the abdomen is called the abdominal ...
between long. The female is larger than the male and generally lighter, ranging generally from fawnish-brown to dark brown. The species is similar to '' Menemerus formosus'' and '' Menemerus transvaalicus'' but differs in the design of its copulatory organs. The male has a short
embolus An embolus (; : emboli; from the Greek ἔμβολος "wedge", "plug") is an unattached mass that travels through the circulatory system, bloodstream and is capable of creating blockages. When an embolus Vascular occlusion, occludes a blood vess ...
with a longer lamella, which is recalled in the species name, and two distinctive tibial appendages, or apophyses, one with a characteristic triangular lobe. Examples found in Zimbabwe have one longer tibial apophysis. The female has a heart-shaped depression in the
epigyne The epigyne or epigynum is the external genital structure of female spiders. As the epigyne varies greatly in form in different species, even in closely related ones, it often provides the most distinctive characteristic for recognizing species. ...
and an unusual insemination duct morphology.


Taxonomy

''Menemerus bifurcus'' 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), ...
of
jumping spider Jumping spiders are a group of spiders that constitute the family (biology), family Salticidae. , this family contained over 600 species description, described genus, genera and over 6,000 described species, making it the largest family of spide ...
that was first described by
Wanda Wesołowska Wanda Wesołowska (born 11 August 1950) is a Polish zoologist known for her work with jumping spiders. She has described more species of jumping spider than any contemporary writer, and is second only to Eugène Simon in the history of arachnolo ...
in 1999. It was one of over 500
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), ...
identified by the Polish
arachnologist Arachnology is the scientific study of arachnids, which comprise spiders and related invertebrates such as scorpions, pseudoscorpions, harvestmen, ticks, and mites. Those who study spiders and other arachnids are arachnologists. More narrowly ...
during her career, making her one of the most prolific in the field. She allocated the spider to the genus ''
Menemerus ''Menemerus'' is a genus of Salticidae, jumping spiders that was first described by Eugène Simon, Eugène Louis Simon in 1868. They are long, flattened in shape, and very hairy, usually with brown and grayish hairs. Most species have white edges ...
''. The genus was first described in 1868 by
Eugène Simon Eugène Louis Simon (; 30 April 1848 – 17 November 1924) was a French naturalist who worked particularly on insects and spiders, but also on birds and plants. He is by far the most prolific spider Taxonomy (biology), taxonomist in history, ...
and contains over 60 species. The genus name derives from two Greek words, meaning certainly and diurnal. The genus shares some characteristics with the genera ''
Hypaeus ''Hypaeus'' is a genus of the spider family Salticidae (jumping spiders). Species , the World Spider Catalog accepted the following species: *'' Hypaeus annulifer'' Simon, 1900 – Brazil *'' Hypaeus barromachadoi'' Caporiacco, 1947 – Guyana ...
'' and ''
Pellenes ''Pellenes'' is a genus of jumping spiders that was first described by Eugène Louis Simon in 1876. It is considered a senior synonym of ''Hyllothyene''. They are dark to black with white stripes on the back, and often have bright red markings. ...
''. Genetic analysis has shown that the genus is related to the genera ''
Helvetia Helvetia () is a national personification of Switzerland, officially , the Swiss Confederation. The allegory is typically pictured in a flowing clothing, with a spear and a shield emblazoned with the Flag of Switzerland, Swiss flag, and commo ...
'' and ''
Phintella ''Phintella'' is a genus of Salticidae, jumping spiders that was first described by W. Bösenberg & Embrik Strand in 1906. Species it contains fifty-nine species and one subspecies, found in Oceania, Asia, Europe, and Africa: *''Phintella abnorm ...
''. The genus was placed in the
tribe The term tribe is used in many different contexts to refer to a category of human social group. The predominant worldwide use of the term in English is in the discipline of anthropology. The definition is contested, in part due to conflict ...
Heliophaninae Chrysillini is a tribe of jumping spider in the family Salticidae. In Maddison's 2015 revision of the family, the subfamily Heliophaninae was reclassified as a junior synonym of Chrysillini. Genera * '' Afraflacilla'' * ''Augustaea'' * ''Ch ...
until that was reconstituted as
Chrysillini Chrysillini is a tribe of jumping spider in the family Salticidae. In Maddison's 2015 revision of the family, the subfamily Heliophaninae was reclassified as a junior synonym of Chrysillini. Genera * '' Afraflacilla'' * '' Augustaea'' * '' ...
by
Wayne Maddison Wayne Paul Maddison (born 1958) is a Canadian evolutionary biologist, arachnologist, and biological illustrator. He is Canada Research Chair in Biodiversity and a professor at the departments of zoology and botany at the University of British ...
in 2015. The tribe is ubiquitous across most of the continents of the world. It is allocated to the subclade Saltafresia in the
clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...
Salticoida Salticoida is an unranked clade of the jumping spider family Salticidae. It is the larger and more widespread of the two subdivisions of the "typical" jumping spiders (subfamily Salticinae), occurring effectively world-wide. Its sister clade is ...
. In 2016, Prószyński created a group of genera named Menemerines after the genus. The vast majority of the species in Menemerines are members of the genus ''Menemerus'', with additional examples from '' Kima'' and ''
Leptorchestes ''Leptorchestes'' is a genus (biology), genus of jumping spiders in the family Salticidae. As in several other genera of salticids, it ant mimicry, mimicks ants. Species * ''Leptorchestes algerinus'' Wanda Wesołowska, Wesołowska & Szeremeta, 2 ...
''. The species name derives from two Latin words, and , which describe the shape of the male's
embolus An embolus (; : emboli; from the Greek ἔμβολος "wedge", "plug") is an unattached mass that travels through the circulatory system, bloodstream and is capable of creating blockages. When an embolus Vascular occlusion, occludes a blood vess ...
.


Description

''Menemerus bifurcus'' is a small spider. The male has a flat dark brown
carapace A carapace is a dorsal (upper) 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 unde ...
that is between long and between wide, covered in short brown and whitish hairs. Lines formed of white hairs line the sides of the carapace. It has a darker eye field. The spider has a very low brown
clypeus The clypeus is one of the sclerites that make up the face of an arthropod. In insects, the clypeus delimits the lower margin of the face, with the labrum articulated along the ventral margin of the clypeus. The mandibles bracket the labrum, but ...
that has white hairs. The
chelicerae The chelicerae () are the arthropod mouthparts, mouthparts of the subphylum Chelicerata, an arthropod group that includes arachnids, horseshoe crabs, and sea spiders. Commonly referred to as "jaws", chelicerae may be shaped as either articulated ...
and labium are light brown; the maxilae and
sternum The sternum (: sternums or sterna) or breastbone is a long flat bone located in the central part of the chest. It connects to the ribs via cartilage and forms the front of the rib cage, thus helping to protect the heart, lungs, and major bl ...
are orange. The
abdomen The abdomen (colloquially called the gut, belly, tummy, midriff, tucky, or stomach) is the front part of the torso between the thorax (chest) and pelvis in humans and in other vertebrates. The area occupied by the abdomen is called the abdominal ...
is between long and typically wide. Most examples have a fawnish-brown abdomen, while some are dark brown. Some have a light pattern of three or four spots, although this is usually quite faint. The underside is light. It has brownish
spinneret A spinneret is a silk-spinning organ of a spider or the larva of an insect. Some adult insects also have spinnerets, such as those borne on the forelegs of Embioptera. Spinnerets are usually on the underside of a spider's opisthosoma, and ar ...
s and brown or orange
legs A leg is a weight-bearing and locomotive anatomical structure, usually having a columnar shape. During locomotion, legs function as "extensible struts". The combination of movements at all joints can be modeled as a single, linear element cap ...
. The
pedipalp Pedipalps (commonly shortened to palps or palpi) are the secondary pair of forward appendages among Chelicerata, chelicerates – a group of arthropods including spiders, scorpions, horseshoe crabs, and sea spiders. The pedipalps are lateral to ...
s are brown with white hairs visible on the palpal femur. The embolus is short with a lamella that is of a slightly longer length. The cymbium has a large lump at its base. The
palpal bulb The two palpal bulbs – also known as palpal organs and genital bulbs – are the copulatory organs of a male spider. They are borne on the last segment of the pedipalps (the front "limbs" of a spider), giving the spider an appearance often descr ...
has a distinctive arrangement of two tibial appendages, or apophyses. One is short and stumpy, pointing upwards, and the other is longer and points downwards. The female is larger than the male. It has a carapace that is between long and between wide and an abdomen between in length and between in width. It is generally lighter. The carapace is fawnish-brown covered with brown hairs. The eye field is dark brown with white hairs. Dark rings encircle the eyes. The chelicerae, labium and maxillae are orange. The sternum is yellow. In some examples, the abdomen is yellowish all over with a covering of brown hairs; in others, it is similar to the male except lighter. The spinnerets are always yellowish. The
epigyne The epigyne or epigynum is the external genital structure of female spiders. As the epigyne varies greatly in form in different species, even in closely related ones, it often provides the most distinctive characteristic for recognizing species. ...
has a wide notch on the rearmost edge and a heart-shaped depression. The copulatory openings lead to wide highly
sclerotized Sclerosis (also sclerosus in the Latin names of a few disorders) is a hardening of tissue and other anatomical features. It may refer to: * Sclerosis (medicine), a hardening of tissue * in zoology, a process which forms sclerites, a hardened exo ...
insemination ducts that have an unusual morphology. There are distinctive accessory glands and small
spermatheca The spermatheca (pronounced : spermathecae ), also called ''receptaculum seminis'' (: ''receptacula seminis''), is an organ of the female reproductive tract in insects, e.g. ants, bees, some molluscs, Oligochaeta worms and certain other in ...
e. Spiders of the ''Menemerus'' genus are difficult to distinguish. The species is particularly similar to the related '' Menemerus formosus'' and '' Menemerus transvaalicus''. Externally, they are hard to distinguish but the copulatory organs are very different. For example, the male has a distinctive triangular retrolateral lobe below an unusual dorsal apophysis which the others lack. The female has more sclerotization throughout its copulatory openings. The shape of the epigyne depression is also distinctive. There are also differences between examples found different areas. The male spiders found in Zimbabwe have a longer tibial apophysis than those from Zambia.


Behaviour

''Menemerus bifurcus'' does not spin webs. Instead, it lives in the tops of trees and descends to attack prey on long threads of silk. The spider makes a dense cocoon when moulting. They live in groups in loose association with each other. They have been noted to mate between September and January. Juveniles appear in both March and April. ''Menemerus'' spiders undertake complex displays and dances during courtship. The males also undertake aggressive displays between themselves. They are hesitant attacking other spiders. The species nests under strips of bark and between flat overlapping flakes of bark. Generally, the spiders are difficult to observe in the wild, being secretive and shy, and using camouflage well.


Distribution and habitat

''Menemerus'' spiders are found throughout Africa and Asia, and have been identified as far as Latin America. ''Menemerus bifurcus'' is found in South Africa, Zambia and Zimbabwe. The male
holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...
was found near
Kitwe Kitwe is the third largest city in terms of infrastructure development (after Lusaka and Ndola) and second largest city in terms of size and population (after Lusaka) in Zambia. With a population of 517,543 (''2010 census provisional'') Kitwe is ...
, Zambia, in 1963. Zimbabwean examples have been seen in
Bulawayo Bulawayo (, ; ) is the second largest city in Zimbabwe, and the largest city in the country's Matabeleland region. The city's population is disputed; the 2022 census listed it at 665,940, while the Bulawayo City Council claimed it to be about ...
in 1962 and
Harare Harare ( ), formerly Salisbury, is the Capital city, capital and largest city of Zimbabwe. The city proper has an area of , a population of 1,849,600 as of the 2022 Zimbabwe census, 2022 census and an estimated 2,487,209 people in its metrop ...
in 1998. Examples found in South Africa are found in
Rust De Winter Nature Reserve Rust de Winter Nature Reserve encloses Rust de Winter Dam near Hammanskraal in the southern Limpopo province, South Africa. Wildlife Game to be viewed include waterbuck, zebra, common warthog, aardvark, crocodile, bushpig and kudu. During ...
in 1972,
Pretoria Pretoria ( ; ) is the Capital of South Africa, administrative capital of South Africa, serving as the seat of the Executive (government), executive branch of government, and as the host to all foreign embassies to the country. Pretoria strad ...
in 1976 and
Tshipise Tshipise is a town in Vhembe District Municipality in the Limpopo province of South Africa. Holiday resort 39 km south-east of Musina and 86 km north-east of Louis Trichardt Louis Trichardt (formerly Trichardtsdorp, and Makhado from ...
in 1979. The spider lives in trees, particularly the bark of ''
Acacia ''Acacia'', commonly known as wattles or acacias, is a genus of about of shrubs and trees in the subfamily Mimosoideae of the pea family Fabaceae. Initially, it comprised a group of plant species native to Africa, South America, and Austral ...
'', ''
Jacaranda ''Jacaranda'' is a genus of 49 species of flowering plants in the family Bignoniaceae, native to tropical and subtropical regions of the Americas while cultivated around the world. The generic name is also used as the common name. The species ' ...
'' and ''
Spathodea ''Spathodea'' is a genus in the plant family Bignoniaceae. The single species it contains, ''Spathodea campanulata'', is commonly known as the African tulip tree. The tree grows between tall and is native to tropical dry forests of Africa. It h ...
'' trees. Examples that live in the Sengwa Wildlife Research Area in Zimbabwe have been found on the bark of trees of the ''
Combretum ''Combretum'', the bushwillows or combretums, make up the type genus of the family Combretaceae. The genus comprises about 272 species of trees and shrubs, most of which are native to Tropics, tropical and southern Africa, about 5 to Madagascar ...
'' genus and trunks of ''
Trichilia ''Trichilia'' is a flowering plant genus in the family (biology), family Meliaceae. These plants are particularly diverse in sub-Saharan Africa and tropical South America. Several species are used in folk medicine and shamanism – e.g. ''Tr ...
'' trees. The spider also lives in houses and areas of habitation, including the museum in Bulawayo.


References


Citations


Bibliography

* * * * * * * * * * * {{{Taxonbar, from=Q1940340 Arthropods of Zimbabwe Invertebrates of Zambia Salticidae Spiders described in 1999 Spiders of Africa Spiders of South Africa Taxa named by Wanda Wesołowska