Spider taxonomy

Paintings of Araneus angulatus from Svenska Spindlar of 1757, the first major work on spider taxonomy

Spider taxonomy is the part of taxonomy that is concerned with the science of naming, defining and classifying all spiders, members of the Araneae order of the arthropod class Arachnida, which has more than 48,500 described species. ^[1] However, there are likely many species that have escaped the human eye as well as specimens stored in collections waiting to be described and classified. It is estimated that only one-third to one half of the total number of existing species have been described. ^[2]

Arachnologists currently divide spiders into two suborders with about 129 families.

Due to constant research, with new species being discovered every month and others being recognized as synonyms, the number of species in the families is bound to change and only reflects the present state of knowledge. Nevertheless, the species numbers given here are useful as a guideline – see the table of families at the end of the article.

History

Spider taxonomy can be traced to the work of Swedish naturalist Carl Alexander Clerck, who in 1757 published the first binomial scientific names of some 67 spiders species in his Svenska Spindlar ("Swedish Spiders"), one year before Linnaeus named over 30 spiders in his Systema Naturae. In the ensuing 250 years, thousands more species have been described by researchers around the world, yet only a dozen taxonomists are responsible for more than one-third of all species described. The most prolific authors include Eugène Simon of France, Norman Platnick and Herbert Walter Levi of the United States, Embrik Strand of Norway, and Tamerlan Thorell of Sweden, each having described well over 1,000 species. ^[3]

Overview of phylogeny

At the very top level, there is broad agreement on the phylogeny and hence classification of spiders, which is summarized in the cladogram below. The three main clades into which spiders are divided are shown in bold; as of 2015 ^[update] , they are usually treated as one suborder, Mesothelae, and two infraorders, Mygalomorphae and Araneomorphae, grouped into the suborder Opisthothelae. ^{[4] [5]} The Mesothelae, with about 140 species in 8 genera as of October 2020 ^[update] , make up a very small proportion of the total of around 49,000 known species. Mygalomorphae species comprise around 7% of the total, the remaining 93% being in the Araneomorphae. ^{[note 1]}

Araneae (spiders)	Mesothelae Opisthothelae Mygalomorphae Araneomorphae Austrochiloidea Entelegynae Haplogynae Hypochiloidea

The Araneomorphae are divided into two main groups: the Haplogynae and the Entelegynae. The Haplogynae make up about 10% of the total number of spider species, the Entelegynae about 83%. ^{[note 1]} The phylogenetic relationships of the Haplogynae, Entelegynae and the two smaller groups Hypochiloidea and Austrochiloidea remain uncertain as of 2015 ^[update] . Some analyses place both Hypochiloidea and Austrochiloidea outside Haplogynae; ^[6] others place the Austrochiloidea between the Haplogynae and the Entelegynae; ^{[7] [8]} the Hypochiloidea have also been grouped with the Haplogynae. ^[9] Earlier analyses regarded the Hypochiloidea as the sole representatives of a group called the Paleocribellatae, with all other araneomorphs placed in the Neocribellatae. ^[10]

The Haplogynae are a group of araneomorph spiders with simpler male and female reproductive anatomy than the Entelegynae. Like the mesotheles and mygalomorphs, females have only a single genital opening (gonopore), used both for copulation and egg-laying; ^[11] males have less complex palpal bulbs than those of the Entelegynae. ^[12] Although some studies based on both morphology and DNA suggest that the Haplogynae form a monophyletic group (i.e. they comprise all the descendants of a common ancestor), ^{[13] [9]} this hypothesis has been described as "weakly supported", with most of the distinguishing features of the group being inherited from ancestors shared with other groups of spiders, rather than being clearly indicative of a separate common origin (i.e. being synapomorphies). ^[14] One phylogenetic hypothesis based on molecular data shows the Haplogynae as a paraphyletic group leading to the Austrochilidae and Entelegynae. ^[15]

The Entelegynae have a more complex reproductive anatomy: females have two "copulatory pores" in addition to the single genital pore of other groups of spiders; males have complex palpal bulbs, matching the female genital structures (epigynes). ^[13] The monophyly of the group is well supported in both morphological and molecular studies. The internal phylogeny of the Entelegynae has been the subject of much research. Two groups within this clade contain the only spiders that make vertical orb webs: the Deinopoidea are cribellate – the adhesive properties of their webs are created by packets of thousands of extremely fine loops of dry silk; the Araneoidea are ecribellate – the adhesive properties of their webs are created by fine droplets of "glue". In spite of these differences, the webs of the two groups are similar in their overall geometry. ^[16] The evolutionary history of the Entelegynae is thus intimately connected with the evolutionary history of orb webs. One hypothesis is that there is a single clade, Orbiculariae, uniting the orb web makers, in whose ancestors orb webs evolved. A review in 2014 concluded that there is strong evidence that orb webs evolved only once, although only weak support for the monophyly of the Orbiculariae. ^[17] One possible phylogeny is shown below; the type of web made is shown for each terminal node in order of the frequency of occurrence. ^[18]

Entelegynae	Eresoidea, RTA clade – no web; substrate-defined web Orbiculariae Deinopoidea – orb web Araneoidea – orb web; aerial sheet web; cobweb; no web Nicodamidae – aerial sheet web

If this is correct, the earliest members of the Entelegynae made webs defined by the substrate on which they were placed (e.g. the ground) rather than suspended orb webs. True orb webs evolved once, in the ancestors of the Orbiculariae, but were then modified or lost in some descendants.

An alternative hypothesis, supported by some molecular phylogenetic studies, is that the Orbiculariae are paraphyletic, with the phylogeny of the Entelegynae being as shown below. ^[19]

Entelegynae	Araneoidea – orb web; aerial sheet web; cobweb; no web Deinopoidea, Oecobiidae– orb web; substrate-defined web RTA clade – no web; substrate-defined web

On this view, orb webs evolved earlier, being present in the early members of the Entelegynae, and were then lost in more groups, ^[20] making web evolution more convoluted, with different kinds of web having evolved separately more than once. ^[17] Future advances in technology, including comparative genomics studies, ^[1] and whole-genome sampling should lead to "a clearer image of the evolutionary chronicle and the underlying diversity patterns that have resulted in one of the most extraordinary radiations of animals". ^[17]

Suborder Mesothelae

Mesothelae resemble the Solifugae ("wind scorpions" or "sun scorpions") in having segmented plates on their abdomens that create the appearance of the segmented abdomens of these other arachnids. They are both few in number and also limited in geographical range.

• †Arthrolycosidae (primitive spiders, extinct)
• †Arthromygalidae (primitive spiders, extinct)
• Liphistiidae (primitive burrowing spiders)
• Heptathelidae (primitive burrowing spiders)

Digitally enhanced image of a Sphodros rufipes that shows the nearly perfectly vertical orientation of the fangs, a prime characteristic of the Mygalomorphae.

Suborder Opisthothelae

Suborder Opisthothelae contains the spiders that have no plates on their abdomens. Opisthothelae is divided into two infraorders, Mygalomorphae and Araneomorphae, which can be distinguished by the orientation of their fangs. It can be somewhat difficult on casual inspection to determine whether the fang orientation would classify a spider as a mygalomorph or araneomorph. The spiders that are called "tarantulas" in English are so large and hairy that inspection of their fangs is hardly necessary to categorize one of them as a mygalomorph. Other, smaller, members of this suborder, however, look little different from the araneomorphs. (See the picture of Sphodros rufipes below.) Many araneomorphs are immediately identifiable as such since they are found on webs designed for the capture of prey or exhibit other habitat choices that eliminate the possibility that they could be mygalomorphs.

Infraorder Mygalomorphae

Megaphobema robustum , one of the many kinds of spiders called "tarantulas"

Spiders in infraorder Mygalomorphae are characterized by the vertical orientation of their fangs and the possession of four book lungs.

Infraorder Araneomorphae

Photograph showing orientation of the fangs of the Araneomorphae.

Most, if not all, of the spiders one is likely to encounter in everyday life belong to infraorder Araneomorphae. It includes a wide range of spider families, including the orb-weaver spiders that weave their distinctive webs in gardens, the cobweb spiders that frequent window frames and the corners of rooms, the crab spiders that lurk on flowers waiting for nectar- and pollen-gathering insects, the jumping spiders that patrol the outside walls of buildings, and so on. They are characterized by having fangs whose tips approach each other as they bite, and (usually) having one pair of book lungs.

Classification above families

Spiders were long classified into families that were then grouped into superfamilies, some of which were in turn placed into a number of higher taxa below the level of infraorder. When more rigorous approaches, such as cladistics, were applied to spider classification, it became clear that most of the major groupings used in the 20th century were not supported. Many were based on shared characteristics inherited from the ancestors of multiple clades (plesiomorphies), rather than being distinct characteristics originating in the ancestors of that clade only (apomorphies). According to Jonathan A. Coddington in 2005, "books and overviews published prior to the last two decades have been superseded". ^[21] Listings of spiders, such as the World Spider Catalog, currently ignore classification above the family level. ^{[21] [22]}

At the higher level, the phylogeny of spiders is now often discussed using informal clade names, such as the "RTA clade", ^[23] the "Oval Calmistrum" clade or the "Divided Cribellum" clade. ^[24] Older names previously used formally are used as clade names, e.g. Entelegynae and Orbiculariae. ^[25]

Table of families

Key

Genera	1	≥2	≥10	≥100
Species	1–9	≥10	≥100	≥1000

Spider families ^{[note 2]}

Family	Genera	Species	Common name	Example
Mesothelae
Heptathelidae	7	113		Kimura spider
Liphistiidae	1	70		Liphistius batuensis
Opisthothelae: Mygalomorphae
Actinopodidae	3	118		Missulena (mouse spiders)
Anamidae	10	111		Aname diversicolor (black wishbone spider)
Antrodiaetidae	4	37	folding trapdoor spiders	Atypoides riversi
Atracidae	3	36	Australian funnel-web spiders	Illawarra wisharti
Atypidae	3	56	purseweb spiders	Sphodros rufipes (red-legged purseweb spider)
Barychelidae	40	282	trapdoor baboon spiders	Sason sundaicum
Bemmeridae	4	47		Spiroctenus personatus
Ctenizidae	2	5	cork-lid trapdoor spiders	Cteniza sauvagesi
Cyrtaucheniidae	6	93	wafer trapdoor spiders	Amblyocarenum nuragicus
Dipluridae	7	95	funnel-web tarantulas	Spruce-fir moss spider (Microhexura montivaga)
Entypesidae	6	42		Entypesa andohahela
Euagridae	14	87		Euagrus formosanus
Euctenizidae	8	77		Aptostichus simus
Halonoproctidae	6	130		Ummidia algarve
Hexathelidae	7	45	venomous funnel-web tarantulas	Hexathele hochstetteri
Hexurellidae	1	4
Idiopidae	23	437	armored trapdoor spiders	Idiosoma nigrum (black rugose trapdoor spider)
Ischnothelidae	5	26
Macrothelidae	2	47
Mecicobothriidae	1	2	dwarf tarantulas
Megahexuridae	1	1
Microhexuridae	1	2
Microstigmatidae	11	38		Envia garciai
Migidae	11	103	tree trapdoor spiders	Moggridgea rainbowi
Nemesiidae	10	148	funnel-web trapdoor spiders	Aname atra (black wishbone spider)
Paratropididae	4	16	baldlegged spiders	Paratropis tuxtlensis
Porrhothelidae	1	5
Pycnothelidae	15	137
Rhytidicolidae	2	14		Fufius lucasae
Stasimopidae	1	47
Theraphosidae	156	1039	tarantulas	Goliath birdeater (Theraphosa blondi)
Opisthothelae: Araneomorphae
Agelenidae	90	1366	araneomorph funnel-web spiders	Hobo spider (Eratigena agrestis)
Amaurobiidae	50	283	tangled nest spiders	Callobius claustrarius
Anapidae	58	232
Anyphaenidae	58	614	anyphaenid sac spiders	Hibana velox (yellow ghost spider)
Araneidae	184	3097	orb-weaver spiders	Zygiella x-notata
Archaeidae	6	90	pelican spiders	Madagascarchaea gracilicollis
Archoleptonetidae	2	8		Archoleptoneta gertschi
Arkyidae	2	38
Austrochilidae	2	9		Hickmania troglodytes
Caponiidae	20	139		Diploglena capensis
Cheiracanthiidae	14	363
Cithaeronidae	2	9
Clubionidae	19	662	sac spiders	Clubiona trivialis
Corinnidae	73	824	dark sac spiders	Castianeira sp.
Ctenidae	48	532	wandering spiders	Phoneutria fera
Cyatholipidae	23	58
Cybaeidae	21	303		Diving bell spider (Argyroneta aquatica)
Cycloctenidae	8	80
Deinopidae	3	67	net-casting spiders	Deinopis subrufa (rufous net-casting spider)
Desidae	60	296	intertidal spiders	Phryganoporus candidus
Dictynidae	53	475		Nigma walckenaeri
Diguetidae	2	15	coneweb spiders
Drymusidae	2	17	false violin spiders
Dysderidae	25	591	woodlouse hunter spiders	Woodlouse spider (Dysdera crocata)
Eresidae	9	102	velvet spiders	Eresus sandaliatus
Filistatidae	19	189	crevice weavers	Southern house spider (Kukulcania hibernalis)
Fonteferridae	1	1		Fonteferrea minutissima
Gallieniellidae	5	41
Gnaphosidae	145	2430	ground spiders	Drassodes cupreus
Gradungulidae	8	17	large-clawed spiders	Progradungula carraiensis (Carrai cave spider)
Hahniidae	24	353	dwarf sheet spiders
Hersiliidae	16	187	tree trunk spiders	Hersilia savignyi
Homalonychidae	1	2
Huttoniidae	1	1		Huttonia palpimanoides
Hypochilidae	2	33	lampshade spiders	Hypochilus thorelli
Lamponidae	23	192		White-tailed spider (Lampona spp.)
Leptonetidae	22	370		Tooth Cave spider (Tayshaneta myopica)
Linyphiidae	624	4724	dwarf / money spiders	Linyphia triangularis
Liocranidae	35	311	liocranid sac spiders
Lycosidae	127	2457	wolf spiders	Lycosa tarantula
Malkaridae	13	57	shield spiders
Mecysmaucheniidae	7	25
Megadictynidae	2	2
Mimetidae	8	159	pirate spiders	Oarces reticulatus
Miturgidae	29	141	long-legged sac spiders
Myrmecicultoridae	1	1
Mysmenidae	14	158	spurred orb-weavers
Nesticidae	18	285	scaffold web spiders	Nesticella marapu
Nicodamidae	7	27
Ochyroceratidae	10	177	midget ground weavers	Theotima minutissima
Oecobiidae	6	120	disc web spiders	Oecobius navus
Oonopidae	115	1888	dwarf hunting spiders	Oonops domesticus
Orsolobidae	30	188
Oxyopidae	9	443	lynx spiders	Peucetia viridans (green lynx spider)
Pacullidae	4	38
Palpimanidae	21	165	palp-footed spiders
Penestomidae	1	9
Periegopidae	1	3
Philodromidae	30	535	philodromid crab spiders	Philodromus dispar
Pholcidae	97	1893	daddy long-legs spiders	Pholcus phalangioides
Phrurolithidae	20	313
Physoglenidae	13	72
Phyxelididae	14	68
Pimoidae	2	85		Pimoa cthulhu
Pisauridae	51	353	nursery web spiders	Pisaura mirabilis
Plectreuridae	2	31
Prodidomidae	23	192
Psechridae	2	61
Psilodercidae	11	224
Salticidae	665	6433	jumping spiders	Zebra spider (Salticus scenicus)
Scytodidae	4	241	spitting spiders	Scytodes thoracica
Segestriidae	5	152	tubeweb spiders	Segestria florentina
Selenopidae	9	262	wall spiders	Selenops radiatus
Senoculidae	1	31
Sicariidae	3	172	recluse spiders	Brown recluse (Loxosceles reclusa)
Sparassidae	95	1337	huntsman spiders	Delena cancerides
Stenochilidae	2	13
Stiphidiidae	20	125	sheetweb spiders	Tartarus mullamullangensis
Symphytognathidae	10	98	dwarf orb-weavers	Patu digua
Synaphridae	3	13
Synotaxidae	1	11
Telemidae	16	104	long-legged cave spiders
Tetrablemmidae	27	151	armored spiders
Tetragnathidae	46	982	long jawed orb-weavers	Leucauge venusta (orchard spider)
Theridiidae	125	2538	cobweb spiders	Redback spider (Latrodectus hasselti)
Theridiosomatidae	20	135	ray spiders	Theridiosoma gemmosum
Thomisidae	171	2167	crab spiders	Misumena vatia (goldenrod crab spider)
Titanoecidae	5	56		Goeldia obscura
Toxopidae	14	82
Trachelidae	20	263
Trachycosmidae	20	148
Trechaleidae	20	148
Trochanteriidae	6	51
Trogloraptoridae	1	1		Trogloraptor marchingtoni
Udubidae	4	15
Uloboridae	19	291	hackled orb-weavers	Uloborus walckenaerius
Viridasiidae	3	14
Xenoctenidae	4	33
Zodariidae	89	1251	ant spiders	Zodarion germanicum
Zoropsidae	27	182		Zoropsis spinimana

Notes

1. Species counts from World Spider Catalog (2020 , Currently valid spider genera and species ), family classification from Coddington (2005 , p. 20).
2. Unless otherwise shown, currently accepted families and counts based on the World Spider Catalog version 22.5 as of 5 November 2021 ^[update] . ^[26] In the World Spider Catalog, "species" counts include subspecies. Assignment to sub- and infraorders based on Coddington (2005, p. 20) (when given there).

References

1. Dimitrov & Hormiga (2021).
2. Platnick & Raven (2013), p. 600.
3. Platnick & Raven (2013), p. 597.
4. Bond et al. (2014).
5. Coddington (2005).
6. Coddington (2005), p. 20.
7. Griswold et al. (2005).
8. Blackledge et al. (2009), p. 5232.
9. Bond et al. (2014), p. 1766.
10. Coddington & Levi (1991), p. 577.
11. Eberhard & Huber (2010), pp. 256–257.
12. Eberhard & Huber (2010), p. 250.
13. Coddington (2005), p. 22.
14. Michalik & Ramírez (2014), p. 312.
15. Agnarsson, Coddington & Kuntner (2013), p. 40.
16. Hormiga & Griswold (2014), p. 488.
17. Hormiga & Griswold (2014), p. 505.
18. Blackledge et al. (2009), Fig. 3.
19. Bond et al. (2014), Fig 3. Web types defined as Blackledge et al. (2009, Fig. 3)
20. Bond et al. (2014), p. 1768.
21. Coddington (2005), p. 24.
22. World Spider Catalog (2020).
23. Hormiga & Griswold (2014), p. 491.
24. Ramírez (2014), p. 4.
25. Hormiga & Griswold (2014), pp. 490–491.
26. World Spider Catalog (2021), Currently valid spider genera and species. sfnp error: no target: CITEREFWorld_Spider_Catalog2021 (help)

Bibliography

• Agnarsson, Ingi; Coddington, Jonathan A. & Kuntner, Matjaž (2013). "Systematics : Progress in the study of spider diversity and evolution". In Penney, David (ed.). Spider research in the 21st century: trends & perspectives. Manchester, UK: Siri Scientific Press. ISBN   978-0-9574530-1-2.
• Blackledge, Todd A.; Scharff, Nikolaj; Coddington, Jonathan A.; Szüts, Tamas; Wenzel, John W.; Hayashi, Cheryl Y. & Agnarsson, Ingi (2009). "Reconstructing web evolution and spider diversification in the molecular era". Proceedings of the National Academy of Sciences. 106 (13): 5229–5234. Bibcode:2009PNAS..106.5229B. doi: 10.1073/pnas.0901377106 . PMC   2656561 . PMID   19289848.
• Bond, Jason E.; Garrison, Nicole L.; Hamilton, Chris A.; Godwin, Rebecca L.; Hedin, Marshal & Agnarsson, Ingi (2014). "Phylogenomics Resolves a Spider Backbone Phylogeny and Rejects a Prevailing Paradigm for Orb Web Evolution". Current Biology. 24 (15): 1765–1771. Bibcode:2014CBio...24.1765B. doi: 10.1016/j.cub.2014.06.034 . PMID   25042592.
• Coddington, Jonathan A. (2005). "Phylogeny and classification of spiders" (PDF). In Ubick, D.; Paquin, P.; Cushing, P.E. & Roth, V. (eds.). Spiders of North America: an identification manual. American Arachnological Society. pp. 18–24. Retrieved 2015-09-24.
• Coddington, Jonathan A. & Levi, Herbert W. (1991). "Systematics and evolution of spiders (Araneae)". Annual Review of Ecology and Systematics. 22: 565–592. doi:10.1146/annurev.es.22.110191.003025. JSTOR   2097274.
• Dimitrov, Dimitar & Hormiga, Gustavo (7 January 2021). "Spider Diversification Through Space and Time". Annual Review of Entomology. 66 (1): 225–241. doi:10.1146/annurev-ento-061520-083414. ISSN   0066-4170. S2CID   221235817.
• Eberhard, W.G. & Huber, B.A. (2010). "Spider genitalia: precise manoeuvers with a numb structure in a complex lock" (PDF). In Leonard, Janet L. & Córdoba-Aguilar, Alex (eds.). The evolution of primary sexual characters in animals. Oxford University Press. ISBN   978-0-19-971703-3 . Retrieved 2015-09-20.
• Griswold, C.E.; Ramirez, M.J.; Coddington, J.A. & Platnick, N.I. (2005). "Atlas of phylogenetic data for entelegyne spiders (Araneae: Araneomorphae: Entelegynae) with comments on their phylogeny" (PDF). Proceedings of the California Academy of Sciences. 56 (Suppl. 2): 1–324. Retrieved 2015-10-11.
• Hormiga, Gustavo & Griswold, Charles E. (2014). "Systematics, Phylogeny, and Evolution of Orb-Weaving Spiders". Annual Review of Entomology. 59 (1): 487–512. doi: 10.1146/annurev-ento-011613-162046 . PMID   24160416.
• Michalik, Peter & Ramírez, Martín J. (2014). "Evolutionary morphology of the male reproductive system, spermatozoa and seminal fluid of spiders (Araneae, Arachnida)–Current knowledge and future directions". Arthropod Structure & Development. 43 (4): 291–322. Bibcode:2014ArtSD..43..291M. doi:10.1016/j.asd.2014.05.005. hdl: 11336/19081 . PMID   24907603.
• Platnick, Norman I. & Raven, Robert J. (2013). "Spider Systematics: Past and Future". Zootaxa. 3683 (5): 595–600. doi: 10.11646/zootaxa.3683.5.8 . PMID   25250473.
• Ramírez, Martín J. (2014). The morphology and phylogeny of dionychan spiders (Araneae, Araneomorphae). Bulletin of the American Museum of Natural History. Vol. 390. hdl:2246/6537.
• World Spider Catalog (2020). "World Spider Catalog version 21.5". Natural History Museum Bern. Retrieved 2020-10-31.

External links

• Abbreviations for Insect and Spider Collections of the World
• International Commission on Zoological Nomenclature
• European and Australian spiders - info and identification
• Spiders of Europe and Greenland
• Information about the largest spider