Thomisidae

{{Short description|Family of spiders}} {{More citations needed|date=December 2025}} {{Redirect-distinguish|Crab spider|spider crab}} {{Use dmy dates|date=April 2026}} {{Automatic taxobox | name = | image = Crab Spider 6299.jpg | image_caption = | image2 = | image2_caption = | fossil_range = {{Fossil range|Palaeogene|present}} | taxon = Thomisidae | authority = Sundevall, 1833{{r|wsc}} | diversity_link = Thomisidae#Taxonomy | diversity = 172 genera, 2,194 species | diversity_ref = {{r|WSC_stats}} | range_map = Thomisidae range map.svg | range_map_caption = blue: reported countries (WSC) green: observation hotspots (iNaturalist) }}

The '''Thomisidae''' are a family of spiders, including about 170 genera and over 2,100 species. The common name '''crab spider''' is often linked to species in this family, but may also be used for spiders from other families. Many members of this family are also known as '''flower spiders''' or '''flower crab spiders'''.<ref name=whyte2017 />

==Etymology== {{Missing information|section|The etymology of "Thomisidae"|date=December 2025}} Spiders in this family are called "crab spiders" due to their body shape, behavior of holding their two front pairs of legs apart from the two rear pairs, and their ability to scuttle sideways or backwards, resembling true crabs.<ref name="britannica" /><ref name=whyte2017 /><ref name=bradley2012 /> The Thomisidae are the family generally referred to as "crab spiders", though some members of the Sparassidae are called "giant crab spiders", the Selenopidae are called "wall crab spiders", and various members of the Sicariidae are sometimes called "six-eyed crab spiders".<ref name="Filmer" /> Some distantly related orb-weaver spider species such as ''Gasteracantha cancriformis'' also are sometimes called "crab spiders".

== Description == [[File:Food chain 2023.jpg|thumb|Crab spider eating a bumblebee.]] Members of this family of spiders are ambush predators and do not spin webs. The two front legs are usually longer and more robust than the other legs. The back two legs are smaller, and are usually covered in a series of strong spines.<ref name="agric" /> Their coloration may be dull with colors such as brown or grey, or very bright green, pink, white or yellow to match their flower. These spiders are quite easy to identify, though can occasionally be confused with the usually larger huntsman spiders.

The spiders of Thomisidae are not known to be harmful to humans. However, spiders of a distantly related genus, ''Sicarius'', which are sometimes referred to as "crab spiders", or "six-eyed crab spiders", are close cousins to the recluse spiders, and are highly venomous, though human bites are rare.

===Sexual dimorphism=== Several different types of sexual dimorphism have been recorded in crab spiders. Some species exhibit color dimorphisms;<ref name="biokids" /> however, the most apparent dimorphism is the difference in size between males and females. In some species, this is relatively small; females of ''Misumena vatia'' are roughly twice the size of their male counterparts.<ref name="zoo_org" /> In other cases, the difference is extreme; on average, female ''Thomisus onustus'' are more than 60 times as massive as the males.<ref name=corcobado2010 />

Several hypothesized explanations are given for the evolution of sexual size dimorphisms in the Thomisidae and other sister taxa.<ref name="hormiga2000" /> The most widely acknowledged hypothesis for female growth is the fecundity hypothesis:<ref name="head1995" /> selection favors larger females so they can produce more eggs and healthier offspring. Because males do not carry and lay eggs, a growth in size does not confer a fitness advantage.<ref name="head1995" />

However, sexual size dimorphism may be a result of male dwarfism. The gravity hypothesis suggests that the smaller size allows the male to travel with greater ease, providing him with an increased opportunity to find mates.<ref name="corcobado2010" /> Females are comparatively stationary, and their larger size allows them to capture larger prey, such as butterflies and bees, granting females the additional nutrients necessary for egg production.<ref name=corcobado2010 />

Other hypotheses propose that sexual size dimorphism evolved by chance, and no selective advantage exists to larger females or smaller males.<ref name=PrenElwoMont98 />

==Behavior== {{unreferenced section|date=October 2015}}

[[File:Crab spider safety line.webm|thumb|thumbtime=31|left|Cf. ''Misumessus oblongus'' jumps with safety line, on yellow ironweed. Repeated at variable slow motion to better see silk line.]]

Thomisidae do not build webs to trap prey, though all of them produce silk for drop lines and sundry reproductive purposes; some are wandering hunters and the most widely known are ambush predators. Some species sit on or beside flowers or fruit, where they grab and kill visiting insects. Individuals of some species, such as ''Misumena vatia'' and ''Thomisus spectabilis'', are able to change color over a period of some days, to match the flower on which they are sitting. Some species await prey among leaves or bark, and some species are excellent mimics of bird droppings and sit out in the open; these species convergently evolved their mimicry with the so-called bird-dropping spiders of Araneidae.

Other species of crab spiders with flattened bodies either hunt in the crevices of tree trunks or under loose bark, or shelter under such crevices by day, and come out at night to hunt. Members of the genus ''Xysticus'' hunt in the leaf litter on the ground. In each case, crab spiders use their powerful front legs to grab and hold on to prey while paralysing it with a venomous bite.

The spider family Aphantochilidae was incorporated into the Thomisidae in the late 1980s; ''Aphantochilus'' species mimic and prey upon ''Cephalotes'' ants.

==Genera== <gallery mode=packed heights=140px> Amyciaea sp..jpg|Ant-mimic ''Amyciaea'' sp., Karnataka, India Angaeus sp.jpg|''Angaeus'' sp.; Karnataka, India Camaricus sp.jpg|''Camaricus'' sp.; Goa, India Misumena vatia female Luc Viatour 1.jpg|female ''Misumena vatia'' Misumenops callinurus by André Nogueira - 362594012.jpeg|''Misumenops calinurus'' consuming a butterfly;{{Clarify|reason=Butterfly species ID needed|date=December 2025}} Porto Alegre, Brazil Nyctimus bistriatus - Melvyn Yeo - 426989606.jpeg|''Nyctimus bistriatus'' (right) with ant prey and scavenging fly; Indonesia Phyrnarachne sp.jpg|''Phyrnarachne'' sp. mimicking bird-dropping, Karnataka, India Runcinia sp.jpg|''Runcinia'' sp., Goa, India </gallery>

{{as of|2026|1}}, 172 genera and 2,195 species were included in this family:<ref name="wsc" /> {{Div col}} * ''Acentroscelus'' Simon, 1886 – South America * ''Acrotmarus'' Tang & Li, 2012 – China * ''Alcimochthes'' Simon, 1886 – China, Japan, Taiwan, Malaysia, Singapore, Vietnam * ''Amyciaea'' Simon, 1886 – Ivory Coast, Sierra Leone, Indonesia, Singapore, Vietnam, India, Australia, New Guinea * ''Angaeus'' Thorell, 1881 – Asia * ''Ansiea'' Lehtinen, 2004 – Africa, Saudi Arabia, Sao Tomé * ''Ansistaria'' Sherwood, 2022 – Africa * ''Aphantochilus'' O. Pickard-Cambridge, 1871 – Argentina, Brazil * ''Apyretina'' Strand, 1929 – Madagascar * ''Australomisidia'' Szymkowiak, 2014 – Australia * ''Avelis'' Simon, 1895 – South Africa * ''Bassaniana'' Strand, 1928 – China, Japan, Korea, Europe, North America * ''Bassaniodes'' Pocock, 1903 – Egypt, West Africa, Asia, Europe * ''Boliscus'' Thorell, 1891 – Asia, New Caledonia * ''Bomis'' L. Koch, 1874 – India, Australia * ''Bonapruncinia'' Benoit, 1977 – St. Helena * ''Boomerangiana'' Szymkowiak & Sherwood, 2021 – Australia * ''Borboropactus'' Simon, 1884 – Africa, Asia, Papua New Guinea * ''Bucranium'' O. Pickard-Cambridge, 1881 – Cuba, Guatemala, Mexico, South America * ''Camaricus'' Thorell, 1887 – Africa, China, Indonesia, Philippines, Vietnam, Bangladesh, India, New Caledonia * ''Cebrenninus'' Simon, 1887 – Asia, West Africa * ''Ceraarachne'' Keyserling, 1880 – Brazil, Colombia * ''Cetratus'' Kulczyński, 1911 – Australia, New Guinea * ''Coenypha'' Simon, 1895 – Argentina, Chile * ''Coriarachne'' Thorell, 1870 – China, Japan, Korea, Caucasus, Turkey, Russia, North America * ''Corynethrix'' L. Koch, 1876 – Australia * ''Cozyptila'' Lehtinen & Marusik, 2005 – Vietnam, Caucasus, Turkey, Europe * ''Crockeria'' Benjamin, 2016 – Indonesia, Malaysia * ''Cymbacha'' L. Koch, 1874 – Sri Lanka, Australia, New Guinea * ''Cymbachina'' Bryant, 1933 – New Zealand * ''Cynathea'' Simon, 1895 – Africa * ''Cyriogonus'' Simon, 1886 – Madagascar * ''Deltoclita'' Simon, 1887 – Brazil, Peru * ''Demogenes'' Thorell, 1895 – Indonesia, India, New Guinea, Vanuatu * ''Diaea'' Thorell, 1869 – Africa, Asia, Russia, United States, Oceania, Colombia * ''Dietopsa'' Strand, 1932 – India * ''Dimizonops'' Pocock, 1903 – Yemen * ''Diplotychus'' Simon, 1903 – Madagascar * ''Domatha'' Simon, 1895 – Philippines, New Guinea * ''Ebelingia'' Lehtinen, 2004 – China, Japan, Korea, Russia * ''Ebrechtella'' Dahl, 1907 – Asia, Russia, Portugal * ''Emplesiogonus'' Simon, 1903 – Madagascar * ''Epicadinus'' Simon, 1895 – Trinidad and Tobago, Panama, Mexico, South America * ''Epicadus'' Simon, 1895 – Mexico to South America * ''Epidius'' Thorell, 1877 – Africa, Asia * ''Erissoides'' Mello-Leitão, 1929 – Brazil * ''Erissus'' Simon, 1895 – Brazil, Peru, Venezuela * ''Felsina'' Simon, 1895 – Cameroon, Senegal, Sierra Leone * ''Firmicus'' Simon, 1895 – Africa, Vietnam, Iran, Israel, Spain, France * ''Geraesta'' Simon, 1889 – Africa * ''Gnoerichia'' Dahl, 1907 – Cameroon * ''Haedanula'' Caporiacco, 1941 – Ethiopia * ''Haplotmarus'' Simon, 1909 – Vietnam * ''Hedana'' L. Koch, 1874 – Indonesia, Malaysia, Myanmar, Sri Lanka, Oceania, Venezuela * ''Henriksenia'' Lehtinen, 2004 – Indonesia, Malaysia, Singapore, Papua New Guinea * ''Herbessus'' Simon, 1903 – Madagascar * ''Heriaesynaema'' Caporiacco, 1939 – Ethiopia * ''Heriaeus'' Simon, 1875 – Africa, Asia, Europe * ''Heterogriffus'' Platnick, 1976 – Angola, Democratic Republic of the Congo, Uganda * ''Hewittia'' Lessert, 1928 – Africa * ''Hexommulocymus'' Caporiacco, 1955 – Venezuela * ''Holopelus'' Simon, 1886 – Africa, Indonesia, India, Sri Lanka * ''Ibana'' Benjamin, 2014 – China, Indonesia, Malaysia * ''Indosmodicinus'' Sen, Saha & Raychaudhuri, 2010 – China, India * ''Indoxysticus'' Benjamin & Jaleel, 2010 – China, India, Sri Lanka * ''Iphoctesis'' Simon, 1903 – Madagascar * ''Isala'' L. Koch, 1876 – Australia * ''Isaloides'' F. O. Pickard-Cambridge, 1900 – Cuba, Hispaniola, Panama, Mexico * ''Kryptochroma'' Machado, 2021 – Brazil, Colombia, French Guiana * ''Lampertia'' Strand, 1907 – Madagascar * ''Latifrons'' Kulczyński, 1911 – Indonesia * ''Ledouxia'' Lehtinen, 2004 – Mauritius, Réunion * ''Loxobates'' Thorell, 1877 – Asia * ''Loxoporetes'' Kulczyński, 1911 – Indonesia, Australia * ''Lycopus'' Thorell, 1895 – China, Japan, Indonesia, Myanmar, Singapore, India, New Guinea * ''Lysiteles'' Simon, 1895 – Asia, Russia * ''Massuria'' Thorell, 1887 – China, Japan, Myanmar, India * ''Mastira'' Thorell, 1891 – Asia, Australia, Samoa * ''Mecaphesa'' Simon, 1900 – North America, Chile, Galapagos * ''Megapyge'' Caporiacco, 1947 – Guyana * ''Metadiaea'' Mello-Leitão, 1929 – Brazil * ''Micromisumenops'' Tang & Li, 2010 – China * ''Misumena'' Latreille, 1804 – Africa, Asia, Europe, United States, Mexico, South America, New Guinea, Papua New Guinea * ''Misumenoides'' F. O. Pickard-Cambridge, 1900 – India, North to South America * ''Misumenops'' F. O. Pickard-Cambridge, 1900 – Africa, Asia, North America * ''Misumessus'' Banks, 1904 – Bermuda, Dominica, Puerto Rico, North America, Grenadines? * ''Modysticus'' Gertsch, 1953 – Mexico, United States * ''Monaeses'' Thorell, 1869 – Africa, Asia, Bulgaria, Ukraine, Greece, Australia, Guyana * ''Musaeus'' Thorell, 1890 – Indonesia * ''Mystaria'' Simon, 1895 – Africa * ''Narcaeus'' Thorell, 1890 – Indonesia * ''Nyctimus'' Thorell, 1877 – South Africa, Indonesia, Malaysia, Thailand, Borneo * ''Ocyllus'' Thorell, 1887 – Myanmar * ''Onocolus'' Simon, 1895 – South America * ''Ostanes'' Simon, 1895 – Ivory Coast, Sierra Leone * ''Oxytate'' L. Koch, 1878 – Africa, Asia, Russia, Australia * ''Ozyptila'' Simon, 1864 – Africa, Asia, Europe, North America * ''Pactactes'' Simon, 1895 – Eastern Africa, South Africa, Ivory Coast * ''Pagida'' Simon, 1895 – Indonesia, Thailand, India, Sri Lanka, Borneo * ''Parabomis'' Kulczyński, 1901 – Africa * ''Parasmodix'' Jézéquel, 1966 – Africa * ''Parastrophius'' Simon, 1903 – Cameroon, Equatorial Guinea, Pakistan * ''Parasynema'' F. O. Pickard-Cambridge, 1900 – Guatemala * ''Paratobias'' F. O. Pickard-Cambridge, 1900 – Honduras, Panama, Mexico * ''Pasias'' Simon, 1895 – Philippines, India * ''Pasiasula'' Roewer, 1942 – Equatorial Guinea * ''Phaenopoma'' Simon, 1895 – South Africa, Senegal, Sierra Leone * ''Pharta'' Thorell, 1891 – Asia * ''Pherecydes'' O. Pickard-Cambridge, 1883 – Africa * ''Philodamia'' Thorell, 1895 – China, Myanmar, Singapore, Bhutan * ''Philogaeus'' Simon, 1895 – Brazil, Chile * ''Phireza'' Simon, 1886 – Brazil * ''Phrynarachne'' Thorell, 1869 – Africa, Asia, New Guinea, Vanuatu, Moluccas * ''Physoplatys'' Simon, 1895 – Paraguay * ''Pistius'' Simon, 1875 – Asia, Russia * ''Plastonomus'' Simon, 1903 – Madagascar * ''Platyarachne'' Keyserling, 1880 – Brazil, French Guiana, Peru * ''Platythomisus'' Doleschall, 1859 – Africa, Asia * ''Poecilothomisus'' Simon, 1895 – Australia * ''Porropis'' L. Koch, 1876 – Angola, Australia, New Guinea * ''Prepotelus'' Simon, 1898 – Mauritius, Réunion * ''Psammitis'' Menge, 1876 – Asia, Europe, Cuba, North America, North Africa * ''Pseudamyciaea'' Simon, 1905 – Indonesia * ''Pseudoporrhopis'' Simon, 1886 – Madagascar * ''Pycnaxis'' Simon, 1895 – Asia * ''Pyresthesis'' Butler, 1880 – Madagascar * ''Rangkayo'' Dhiya'ulhaq & Benjamin, 2025 – Indonesia * ''Reinickella'' Dahl, 1907 – Indonesia * ''Rejanellus'' Lise, 2005 – Cuba, Hispaniola, Puerto Rico * ''Rhaebobates'' Thorell, 1881 – New Guinea * ''Runcinia'' Simon, 1875 – Africa, Asia, Russia, Spain, Australia, New Guinea * ''Runcinioides'' Mello-Leitão, 1929 – Argentina, Brazil, French Guiana * ''Saccodomus'' Rainbow, 1900 – Australia * ''Scopticus'' Simon, 1895 – Indonesia * ''Sidymella'' Strand, 1942 – Australia, New Zealand, South America * ''Simorcus'' Simon, 1895 – Africa, China, Yemen * ''Sinothomisus'' Tang, Yin, Griswold & Peng, 2006 – China * ''Smodicinodes'' Ono, 1993 – China, Malaysia, Thailand * ''Smodicinus'' Simon, 1895 – Africa * ''Soelteria'' Dahl, 1907 – Madagascar * ''Spilosynema'' Tang & Li, 2010 – China * ''Spinaarachne'' Machado, 2025 – Australia * ''Spiracme'' Menge, 1876 – Asia, Eastern Europe, North America * ''Stephanopis'' O. Pickard-Cambridge, 1869 – China, Indonesia, Oceania * ''Stephanopoides'' Keyserling, 1880 – Panama, South America * ''Stiphropella'' Lawrence, 1952 – South Africa * ''Stiphropus'' Gerstaecker, 1873 – Africa, Asia * ''Strigoplus'' Simon, 1886 – China, Indonesia, Malaysia, Myanmar, India * ''Strophius'' Keyserling, 1880 – Mexico to Paraguay * ''Sylligma'' Simon, 1895 – Africa * ''Synaemops'' Mello-Leitão, 1929 – Argentina, Brazil * ''Synalus'' Simon, 1895 – Australia * ''Synema'' Simon, 1864 – Worldwide except Australia * ''Tagulinus'' Simon, 1903 – Vietnam * ''Tagulis'' Simon, 1895 – Africa, Sri Lanka * ''Talaus'' Simon, 1886 – South Africa, Asia * ''Tarrocanus'' Simon, 1895 – Sri Lanka * ''Taypaliito'' Barrion & Litsinger, 1995 – Philippines * ''Tharpyna'' L. Koch, 1874 – Indonesia, India, Australia * ''Tharrhalea'' L. Koch, 1875 – Madagascar, Indonesia, Philippines, Oceania * ''Thomisops'' Karsch, 1879 – Africa, China * ''Thomisus'' Walckenaer, 1805 – Worldwide * ''Titidiops'' Mello-Leitão, 1929 – Brazil * ''Titidius'' Simon, 1895 – South America * ''Tmarus'' Simon, 1875 – Worldwide * ''Trichopagis'' Simon, 1886 – Gabon, Madagascar, South Africa, Guinea * ''Ulocymus'' Simon, 1886 – Argentina, Brazil * ''Uraarachne'' Keyserling, 1880 – South America * ''Wechselia'' Dahl, 1907 – Argentina * ''Xysticus'' C. L. Koch, 1835 – Worldwide * ''Zametopina'' Simon, 1909 – China, Thailand, Vietnam * ''Zygometis'' Simon, 1901 – Thailand to Australia {{Div col end}}

==See also== * Philodromidae, also called crab spiders

==References== {{Reflist|refs= <ref name="wsc">{{cite web |url=https://wsc.nmbe.ch/family/103 |title=Family: Thomisidae Sundevall, 1833 |publisher=World Spider Catalog |doi=10.24436/2 |access-date=18 January 2026 }}</ref> <ref name="agric">{{Cite web |title=Thomisidae - General Information |url=https://www.arc.agric.za/arc-ppri/Pages/Biosystematics/Spider%20Research%20Centre/Thomisidae-General-Information.aspx |access-date=17 September 2022 |website=www.arc.agric.za }}</ref> <ref name="biokids">{{Cite web |title=BioKIDS - Kids' Inquiry of Diverse Species, Thomisidae: INFORMATION |url=http://www.biokids.umich.edu/critters/Thomisidae/ |access-date=6 January 2022 |website=www.biokids.umich.edu }}</ref> <ref name="bradley2012">{{cite book |last1=Bradley |first1=Richard A. |title=Common Spiders of North America |date=2012 |publisher=University of California Press |isbn=9780520954502 }}</ref> <ref name="britannica">{{Cite web |title=crab spider {{!}} arachnid {{!}} Britannica |url=https://www.britannica.com/animal/crab-spider |access-date=17 September 2022 |website=www.britannica.com |language=en }}</ref> <ref name="corcobado2010">{{cite journal |last1=Corcobado |first1=G. |last2=Rodríguez-Gironés |first2=M.A. |last3=De Mas |first3=E. |last4=Moya-Laraño |first4=J. |year=2010 |title=Introducing the refined gravity hypothesis of extreme sexual size dimorphism |journal=BMC Evolutionary Biology |volume=10 |issue=1 |page=236 |bibcode=2010BMCEE..10..236C |doi=10.1186/1471-2148-10-236 |pmc=2924870 |pmid=20682029 |doi-access=free }}</ref> <ref name="Filmer">{{cite book |last=Filmer |first=Martin |title=Southern African Spiders |publisher=BHB International / Struik |location=City |year=1997 |isbn=1-86825-188-8 }}</ref> <ref name="head1995">{{cite journal |last1=Head |first1=G |year=1995 |title=Selection on Fecundity and Variation in the Degree of Sexual Size Dimorphism Among Spider Species (Class Araneae) |journal=Evolution |volume=49 |issue=4 |pages=776–781 |doi=10.2307/2410330 |jstor=2410330 |pmid=28565139 }}</ref> <ref name="hormiga2000">{{cite journal |last1=Hormiga |first1=G |last2=Scharff |first2=N |last3=Coddington |first3=J.A. |year=2000 |title=The Phylogenetic Basis of Sexual Size Dimorphism in Orb-Weaving Spiders (Araneae, Obiculariae) |journal=Systematic Biology |volume=49 |issue=3 |pages=435–462 |doi=10.1080/10635159950127330 |pmid=12116421 |doi-access=free }}</ref> <ref name="PrenElwoMont98">{{Cite journal |last1=Prenter |first1=J. |last2=Elwood |first2=R.W. |last3=Montgomery |first3=W.I. |year=1998 |title=No Association between Sexual Size Dimorphism and Life Histories in Spiders |journal=Proceedings of the Royal Society of London B: Biological Sciences |volume=265 |issue=1390 |pages=57–62 |doi=10.1098/rspb.1998.0264 |name-list-style=amp |pmc=1688762 }}</ref> <ref name="whyte2017">{{cite book |last1=Whyte |first1=Robert |last2=Anderson |first2=Greg |title=A field guide to spiders of Australia |date=2017 |publisher=Csiro Publishing |isbn=9780643107083 }}</ref> <ref name="WSC_stats">{{cite web |title=Families |url=http://www.wsc.nmbe.ch/families |access-date=23 January 2026 |work=World Spider Catalog |publisher=Natural History Museum Bern }}</ref> <ref name="zoo_org">{{Cite web |title=Flower (a.k.a. Goldenrod) Crab Spider (''Misumena vatia'') |url=http://www.zoo.org/document.doc?id=203 |access-date=30 October 2015 |publisher=Woodland Park Zoo }}</ref> }}

==External links== * [http://www.forestryimages.org/browse/subimages.cfm?SUB=4319 Pictures of crab spiders] (free for noncommercial use) * [http://calphotos.berkeley.edu/cgi/img_query?where-genre=Animal&query_src=photos_fauna_index&rel-taxon=contains&where-taxon=Misumena+vatia Photos of crab spiders] hosted by University of California, Berkeley

Category:Thomisidae Category:Araneomorphae families Category:Taxa named by Carl Jakob Sundevall Category:Articles containing video clips