Masana kimiyya na zamani sunyi la'akari da crustaceans, tsoffin ƙwayoyin cuta arthropods, halittu na musamman masu ban mamaki. Daga matsayin asalin sassalar, danginsu na kusa a duniyar dabba ta zamani sune dunƙulen dawakai, mazauninsu yanki ne mara zurfi na Atlantika, Indiya da Pasifik Pacific, da kuma nesa kunama da gizo-gizo.

A cikin bayyanar, kunamai sun yi kama da manyan kunama. Tsawon jikinsu ya kai mita da yawa. Kamar kunama, kunama sun mallaki manyan makamai - makamin guba wanda yake a ƙarshen wutsiya. Manyan dabbobin da ke da haɗari suna ɗauke da manyan maganganu masu ƙarfi ko dogon tsinkaye waɗanda ke taimaka wa dabbobi su kama abin da aka kama. An yi gyaran kafafu na haɓaka daga cikin juyawa.

Manyan crustaceans - manyan giwayen da suka rayu a cikin tekuna da kuma tekun lokacin Devonian - sun mamaye wani wuri na musamman tsakanin mashigan ruwa. Da zarar yana ɗaya daga cikin ƙungiyoyi da yawa na tsoffin dabbobin da suka mutu don dalilai ba a sani ba.

Rana ta yawan crustaceans, a cewar masana kimiyya, ya fadi akan Silurian da Devonian. Gidajen su yalwataccen wuri, lagoons mai zurfin tunani waɗanda suka mamaye yanayin duniyar duniyar a wancan lokacin. A cikin makwabta tare da masu farautar, nau'ikan kifaye iri daban daban sun rayu, har da trilobites, waɗanda suka kafa tushen abincin crustaceans.

[gyara] Juyin Halitta

Racoscorpions ya wanzu cikin zamanin Paleozoic - 510-248 miliyan da suka gabata. Siffofin farko sun rayu cikin ruwa mai zurfi a cikin tekuna. Kimanin shekaru miliyan 325-299 da suka shude, yawancin ɓarnatattun abubuwa sun zo rayuwa ne cikin ruwa mai tsarkak .wa.

Racoscorpions na iya tafiya zuwa ƙasa.

A wannan batun, crustaceans suna da ban sha'awa a matsayin misalin canji daga rayuwa a cikin teku zuwa rayuwa akan ƙasa.

[gyara] Masanin ilimin lissafi

Racoscorpions ya kasance girmansa daga 20 cm zuwa 2.5 har ma da m 3. Babban sananniyar arthropods na 'yan ɓoye ne - Jaekelopterus rhenaniae, wanda ya rayu kimanin miliyan 460-255 da suka wuce, kuma yana da tsawon mita 2.5.

Suna da ƙuguna kamar dama wanda ya ba su damar yin iyo ko ragi a gindin.

Rarrabawa

Umurnin ya hada da dangin Pterygotidae, wanda ya rayu shekaru miliyan 470-370 da suka gabata. Sun kasance membobin mambobin Pterygotioidea. Wannan rukunin ya ƙunshi mutane waɗanda aka yi la’akari da su mafi girma arthropods a cikin tarihin duniyar. Tsawon jikin waɗannan halittun ya kai mita biyu da rabi. Ya hada da haihuwar da yawa: Acutiramus - wanda ya rayu daga Late Silurian zuwa farkon Devonian. Nazarin a cikin 2011 ya nuna cewa wannan dabba mai yiwuwa wataƙila ce ko ma phytophage.

Mafi girman sanannun arthropods suna cikin crustaceans - Jaekelopterus rhenaniae, wanda ya rayu kimanin miliyan 460-255 shekaru da suka gabata kuma yana da tsawon mita 2.5.