Wikipedia

Evarcha ignea

Evarcha ignea is a species of jumping spider in the genus Evarcha that lives in Nigeria, South Africa and Zimbabwe. It is ground-dwelling spider, thriving in leaf litter, but has also been observed living on the walls of houses. The species was first described in 2008 by Wanda Wesołowska and Meg Cumming, although the female was not described until the year after. The spider is small, with a rounded cephalothorax that is usually between 1.9 and 2.5 mm (0.07 and 0.10 in) long and an ovoid abdomen that is between 1.6 and 2.2 mm (0.06 and 0.09 in) long. The female is slightly larger than the male. It is also lighter. The male has a mostly dark brown carapace and russet-brown abdomen, while the female's carapace is whitish-yellow and abdomen creamy. The male spider's face, or clypeus, is covered in bright scarlet scale-like hairs, which gives the spider its name, which can be translated "fiery". This is similar to the related Evarcha bakorensis. To distinguish this species from others in the genus, it is necessary to compare their copulatory organs. The male Evarcha ignea has a distinctive small notch on the spike, or apophysis, that emanates from its palpal tibia. The female has shorter insemination ducts than other species, and spermathecae that have a large first chamber.

Evarcha ignea
The related Evarcha arcuata
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Chelicerata
Class: Arachnida
Order: Araneae
Infraorder: Araneomorphae
Family: Salticidae
Subfamily: Salticinae
Genus: Evarcha
Species:
E. ignea
Binomial name
Evarcha ignea
Wesołowska & Cumming, 2008
Synonyms
  • Evawes ignea (Wesołowska & Cumming, 2008)

Taxonomy edit

Evarcha ignea is a species of jumping spider that was first described by Wanda Wesołowska and Meg Cumming in 2008.[1] Initially only the male was described; a description of the female was first published by Wesołowska and Charles Hadded in 2009. It was one of over 500 species identified by the Polish arachnologist Wesołowska during her career, making her the most prolific modern author in the field.[2] They allocated it to the genus Evarcha, first circumscribed by Eugène Simon in 1902. The genus is one of the largest, with members found on four continents.[3]

In 1976, Jerzy Prószyński placed the genus was placed in the subfamily Pelleninae, along with the genera Bianor and Pellenes.[4] In Wayne Maddison's 2015 study of spider phylogenetic classification, the genus Evarcha was moved to the subtribe Plexippina.[5] This is a member of the tribe Plexippini, in the subclade Simonida in the clade Saltafresia.[6] It is closer to the genera Hyllus and Plexippus.[7] Analysis of protein-coding genes showed it was particularly related to Telamonia.[8] In the following year, Prószyński added the genus to a group of genera named Evarchines, named after the genus, along with Hasarinella and Nigorella based on similarities in the spiders' copulatory organs.[9]

Prószyński placed the spider in a new genus Evawes in 2018 based on its copulatory organs and the way that they differ from other Evarcha spiders. The new genus name is a combination of Evacha and Wesołowska.[10] This designation is not widely accepted and the species remains in the Evarcha genus in the World Spider Catalog.[1][11] The species is named for a Latin word that can be translated "fiery", and points to the spider's face, or clypeus.[12]

Description edit

Evarcha ignea is a small spider. The spider's body is divided into two main parts: a rather rounded almost rectangular cephalothorax and more pointed and ovoid abdomen that is narrower to the rear.[13] The male has a carapace, the hard upper part of the cephalothorax, that is between 1.9 and 2.3 mm (0.07 and 0.09 in) long and 1.5 and 1.8 mm (0.06 and 0.07 in) wide. It is generally dark brown with a brown streak down the middle and a thin black line at the edges. The eye field is black.[14] There is a patch of white hairs at the back of the eye field, with more scattered on the carapace, and long brown bristles near the eyes themselves. There are orange scales near some of the eyes. The underside of the cephalothorax, or sternum, is yellow, with a tint of grey. The clypeus is high and covered in bright scarlet scale-like hairs, the brightness of which give the spider its name. The spider's mouthparts, including the labium, are generally brown. The chelicerae has a single tooth.[15]

The male spider's abdomen is between 1.6 and 2.2 mm (0.06 and 0.09 in) long and 1.1 and 1.4 mm (0.04 and 0.06 in) wide.[14] It is russet-brown on top with a yellowish pattern of light chevrons to the back. A covering of long dark hairs adorns the surface, which are longer and denser to the front edge. On some examples, the abdomen has a light patch and others a small delicate orange scutum. The underside is usually grey, but in some examples it is yellow with a pattern of dark dots making three lines. The spinnerets are yellowish-grey. It has legs that are mainly brown, although the tarsi are yellow and there are lighter rings visible on some of the joints.[15] The front legs are longer than the others. The legs have brown hairs and long spines. The pedipalps, sensory organs near the mouth, are dark.[16]

The male's copulatory organs are distinctive. The palpal tibia has a wide protrusion, or tibial apophysis that has an end with a small notch which accentuates its sharp tip. The palpal bulb is rhomboid with a large bulbous protrusion at its base. There is a very thin embolus emanating from near the top of the bulb that hugs the top of the bulb. The cymbium is rather large.[17][18] It is the shape of the copulatory organs that help distinguish the spider from others in the genus. For example, the related Evarcha bakorensis has a similar clypeus, but its tibial apophysis is blunt and lacks the small notch that is characteristic of this species. Conversely, both Evarcha acuta and Evarcha amanzi have a larger notch.[12][19]

The female is slightly larger in size to the male, with a cephalothorax that is typically 2.5 mm (0.10 in) long, and 1.9 mm (0.07 in) wide and an ovoid abdomen that is 2.2 mm (0.09 in) in length and 1.6 mm (0.06 in) in width. It is similar in proportion but generally lighter than the male.[20] The carapace is whitish-yellow and the eye field is grey. The pattern consists of a large light chevron on the rear of the eye field and a thin belt formed of brown hairs that follows the border around the top and the sides. There are black rings round the eyes themselves, some of which are surrounded by white hairs. The underside is light and without a pattern. The clypeus is low and yellow, less bright than the male. The mouthparts, including the chelicerae, are also lighter than the male. The abdomen is creamy with a covering of brown hairs.[21]

The female copulatory organs are distinctive. The epigyne has copulatory openings to the rear that lead to relatively simple insemination ducts and multi-chambered spermathecae or receptacles. The accessory glands are long.[22] It is similar to the related Evarcha arabica and Evarcha certa, particularly in its internal structure. However, the insemination ducts are shorter and the first chamber of the spermathecae are larger.[21]

Distribution and habitat edit

Evarcha spiders live across the world, although those found in North America may be accidental migrants.[23] Evarcha ignea is endemic to Africa.[24] It lives in Nigeria, South Afica and Zimbabwe.[1] The male holotype was discovered in a house in Zimbabwe in 1999.[12] Retrospectively, it was also recognised as living in Nigeria, the first instance being in Cross River State in 1984, when two males were seen, one in the village of Akim akim and another in Calabar.[25] The first example to be identified in South Africa was found in the Ndumo Game Reserve in 2005.[15] Up to this point, all the spiders discovered had been male. The first female was found in Tembe Elephant Park in KwaZulu-Natal, approximately 15 kilometres (9.3 mi) east of the first South African find. A male was found at the same time, confirming their identity.[21][26]

The spider lives in a range of environments. It is ground-dwelling, and often lives in leaf litter found on the floor of forests and savanna.[27] It seems to thrive in forests of Senegalia nigrescens trees. The spider has also been found living in the bark of Commiphora harveyi trees.[15] The species also seems to live in areas of human habitation. The holotype was found climbing a kitchen wall.[16] Its conservation status is considered of least concern.[24]

References edit

Citations edit

  1. ^ a b c World Spider Catalog (2017). "Evarcha ignea Wesolowska & Cumming, 2008". World Spider Catalog. 18.0. Bern: Natural History Museum. Retrieved 24 March 2017.
  2. ^ Wiśniewski 2020, p. 6.
  3. ^ Prószyński 2018, p. 132.
  4. ^ Maddison & Hedin 2003, p. 540.
  5. ^ Maddison 2015, p. 250.
  6. ^ Maddison 2015, pp. 246, 280.
  7. ^ Maddison, Bodner & Needham 2008, p. 56.
  8. ^ Maddison & Hedin 2003, p. 536.
  9. ^ Prószyński 2017, p. 51.
  10. ^ Prószyński 2018, p. 153.
  11. ^ Kropf et al. 2019, p. 445.
  12. ^ a b c Wesołowska & Cumming 2008, p. 175.
  13. ^ Wesołowska & Haddad 2009, p. 95.
  14. ^ a b Wesołowska & Haddad 2009, p. 30.
  15. ^ a b c d Wesołowska & Haddad 2009, p. 32.
  16. ^ a b Wesołowska & Cumming 2008, p. 176.
  17. ^ Wesołowska & Haddad 2009, p. 31.
  18. ^ Prószyński 2018, p. 155.
  19. ^ Wesołowska & Haddad 2018, p. 886.
  20. ^ Haddad & Wesołowska 2013, p. 478.
  21. ^ a b c Haddad & Wesołowska 2013, p. 471.
  22. ^ Haddad & Wesołowska 2013, p. 470.
  23. ^ Maddison & Hedin 2003, p. 543.
  24. ^ a b Dippenaar-Schoeman, Foord & Haddad 2021, p. 13.
  25. ^ Wesołowska & Edwards 2012, p. 745.
  26. ^ Haddad & Wesołowska 2013, p. 469.
  27. ^ Haddad & Wesołowska 2013, p. 472.

Bibliography edit

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