Icius Mbitaensis
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''Icius mbitaensis'' is a species of jumping spider in the genus '' Icius'' that lives in Kenya. It was first described in 2011 by Wanda Wesołowska. The spider lives communally in individual nests amongst other spiders and preys on insects, relying on its good eyesight to hunt diurnally. It is small, with a
cephalothorax The cephalothorax, also called prosoma in some groups, is a tagma of various arthropods, comprising the head and the thorax fused together, as distinct from the abdomen behind. (The terms ''prosoma'' and ''opisthosoma'' are equivalent to ''cepha ...
between long and an abdomen long. The female and male are similar in size and colouration of the
carapace A carapace is a Dorsum (biology), 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 tor ...
. The male abdomen is grey-brown with a faint pattern visible on some specimens. The female has a brown abdomen, sometimes more reddish-brown to the front, with some examples having a patch in the middle and spots to the back. The species is similar to other ''Icius'' spiders but differs in the size of the embolus and tibial apophysis of the male and the epigynal depression and pockets, seminal ducts and spermathecae of the female.


Taxonomy

''Icius mbitaensis'' is a jumping spider that was first described by Wanda Wesołowska in 2011. It was one of over 500 species identified by the Polish arachnologist during her career. The species had initially been named '' Pseudicius'' sp.2 by Robert Jackson in 1986. Wesołowska allocated it to the genus '' Icius'', which had been raised 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 taxonomist in history, describing over 4, ...
in 1876. The genus name is based on two Greek words that can be translated distinct, or special, face. The species is named after the place where it was found. The genus was provisionally placed alongside ''Pseudcius'', which, despite having superficially similar spelling, has a different etymology. In 1984, Ekaterina Andreeva, Stefania Hęciak and
Jerzy Prószyński Jerzy Prószyński (born 1935 in Warsaw) is a Polish arachnologist specializing in systematics of jumping spiders (family Salticidae). He is a graduate of the University of Warsaw, a long-term employee of the Siedlce University of Natural Scienc ...
looked to combine the genera. The two genera have similar copulatory structures but work by Wayne Maddison in 1987 demonstrated that they have very different DNA. The genus is a member of the tribe
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'' * '' ...
, within the subclade Saltafresia in the
clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...
Salticoida. Chrysillines, which had previously been termed heliophanines, are
monophyletic In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic gro ...
. In 2016,
Jerzy Prószyński Jerzy Prószyński (born 1935 in Warsaw) is a Polish arachnologist specializing in systematics of jumping spiders (family Salticidae). He is a graduate of the University of Warsaw, a long-term employee of the Siedlce University of Natural Scienc ...
split the genus from the Chrysillines into a group called Iciines, named after the genus. He stated the split was for practical reasons as Chrysillines had become unwieldy.


Description

''Icius mbitaensis'' is a small spider. The male has a
cephalothorax The cephalothorax, also called prosoma in some groups, is a tagma of various arthropods, comprising the head and the thorax fused together, as distinct from the abdomen behind. (The terms ''prosoma'' and ''opisthosoma'' are equivalent to ''cepha ...
that is between long and typically wide. The oval
carapace A carapace is a Dorsum (biology), 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 tor ...
is flattened, brown and covered in translucent hairs. The eye field is darker and irridescent, with a black area around the eyes themselves. The chelicerae are dark brown and
unidentate In coordination chemistry, denticity () refers to the number of donor groups in a given ligand that bind to the central metal atom in a coordination complex. In many cases, only one atom in the ligand binds to the metal, so the denticity equals ...
. The labium is dark brown. The oval abdomen is similar in size to the carapace, typically long and wide. It is generally grey-brown, with occasional light streaks or faint lighter patches. The underside is lighter. The spinnerets are brown. The front
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 ...
are long and brown, while the remainder are yellow. All the legs have brown hairs. The pedipalps are brown. The embolus is long and bends back to the palpal bulb. The tibial apophysis, or appendage, is wide with a curved pointed tip. The female is similar than the male, with a
cephalothorax The cephalothorax, also called prosoma in some groups, is a tagma of various arthropods, comprising the head and the thorax fused together, as distinct from the abdomen behind. (The terms ''prosoma'' and ''opisthosoma'' are equivalent to ''cepha ...
that is typically long and wide and an abdomen between long and between wide. The carapace is similar in colour, with white streaks on the edge extending to the clypeus. The abdomen is brown, although, in some examples, it has a reddish-brown tinge towards the front. Some specimens have a pattern of a large patch in the middle of the abdomen and two round spots to the back. Unlike the male, the front leg is the same width as the others. 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 heart-shaped depression which is flanked by large pockets of roughly the same length. The seminal ducts are long and the spermathecae are particularly long and thin. The species is closely related to '' Icius steeleae''. The male has a shorter tibial apophysis and longer embolus, while the female can be distinguished by the length of the seminal ducts, spermathecae and epigyne pocket and depression. The last two are particularly noticeable as they are equally long in the species, unlike other species in the genus. The female is also similar to '' Icius grassei'', differing in the spacing of the copulatory openings.


Behavior

''Icius mbitaensis'' lives communally in large nests within the complicated interconnected webs of other spiders. Each spider lives in its own territorial nest within the complex. The males live with immature females in their nests until they are able to mate, at which time they perform complex courtship rituals. The courtship activity is vibratory in the nests and visual outside the nests. The males will also embrace each other when they meet. Like many jumping spiders, it does not spin webs to capture prey. Instead, it is mainly a diurnal hunter that uses its good eyesight to spot its prey. The spider preys on insects. As prey itself for the species '' Evarcha culicivora'', there is no significant preference for the predator between spiders that eat mosquitoes that had blood inside them and those that do not. The spider uses visual displays during courtship and transmits vibratory signals through silk to communicate to other spiders.


Distribution

''Icius mbitaensis'' is endemic to Kenya. The holotype was discovered in 1998 on the banks of
Lake Victoria Lake Victoria is one of the African Great Lakes. With a surface area of approximately , Lake Victoria is Africa's largest lake by area, the world's largest tropical lake, and the world's second-largest fresh water lake by surface area after ...
. Other examples have also been found locally.


References


Citations


Bibliography

* * * * * * * * * * * * {{Taxonbar, from=Q4473181 Endemic fauna of Kenya Salticidae Spiders of Africa Spiders described in 2011 Taxa named by Wanda Wesołowska