Plesiosaur: sunan barkwanci "dinosaur na ruwa"

Plesiosaur shine a barewa tsari na sauropsids Sun bayyana a farkon Jurassic. Sun zauna dukan tekuna, wani abu da ya sa aka gane su a matsayin "dinosaurs na ruwa" ko da yake wannan sunan dole ne a yi la'akari da kuskure.

Lokaci-lokaci, ana cewa mai yiyuwa ne har yanzu suna zaune a cikin ruwan teku. Fiye da duka, a cikin abubuwan da ba za a iya bayyana su ba waɗanda aka samu ruɓaɓɓen gawar kifin sharks ko yaudara. Ko da yake babu shaida don ci gaba da wanzuwa.

Menene plesiosaur?

Plesiosaurs an lakafta su "dinosaur na ruwa," amma bai kamata a yi la'akari da su dinosaur ba. Wadannan dabbobi ya zauna cikin teku tsakanin miliyan 200 da miliyan 65 da suka wuce. Lokacin da suke tafiya cikin teku, kusan sun kasance a duk faɗin duniya.

Kamar yadda suke?

A cikin ruwaye waɗannan dabbobi ko dabbobi masu rarrafe na ruwa waɗanda ake kira plesiosaurs suna rayuwa. Su Jikuna suna da faɗi da silinda, manya, kuma suna iya kaiwa tsayin mita 15; kawunansu karami ne, wuyansu dogo ne sosai, jelar kuma gajere ne kuma suna da manyan firam don motsawa cikin sauƙi.

Wadannan dabbobi Sun zauna tare a zamanin dinosaur kuma sun bace a lokaci guda., amma duk da haka, ba su da alaƙa kusa da dinosaurs. Don haka bai kamata a dauke su kamar haka ba.

Sun rayu a zurfin zurfin cikin ruwa saboda buƙatar su na numfashi a waje daga gare su.

An bayyana su fiye da sau ɗaya a matsayin "kunkuru masu maciji a ciki" amma ba ruwansu da ɗaya ko ɗaya. Wasu na ganin cewa wadannan dabbobin za su fita ne domin fitar da ƙwai daga cikin ruwa kuma bayan ƙyanƙyashe sai su sake ja da kansu cikin ruwan. Babu wani abu da ya wuce daga gaskiya, sun haifi 'ya'yansu a raye, kamar yadda dabbar shayarwa ta yi. 

Hanyar yin iyo na iya kama da na penguins. Wato a ce, Suka yi motsi kamar za su tashi a cikin ruwa.

Plesiosaur a cikin Iberian Peninsula

A cikin Iberic Peninsle An gano mahimman abubuwan burbushin halittu a Morella (Castellón). A cikin wadannan ajiya, an sami wani vertebra na plesiosaur, wanda har sai lokacin ba a sami ragowar gawa ba a cikin tsibirin: leptocleid.

Leptocleid

sun kasance plesiosaurs karami, a mafi yawansu za su iya kai mita 3 a tsayi kuma yana da ɗan gajeren wuya. Musamman, waɗannan ruwaye marasa zurfi suna zaune.

Dabbobin da aka samu a ciki Dole ne Morella ya zauna a yankin shekaru miliyan 125 da suka wuce, wanda zai dace da ƙananan Cretaceous. Dole ne mu yi tunanin cewa tsibirin ya canza da yawa a cikin ƙarni kuma a lokacin za a sami babban delta a bakin tekun.

A cikin ciwon daji na leptocleid. An yi imanin cewa ban da ruwa na ruwa sun sami damar daidaitawa da ruwa maras nauyi kuma suna rayuwa kusa da bakunan koguna da kusa da abubuwa.

juyin halittar plesiosaur

plesiosaur Mafi na farko da aka samu, suna da ƙaramin kai da dogayen wuya. Wadannan zasu samo asali kimanin shekaru miliyan 220 da suka wuce a cikin Upper Triassic, wanda zai haifar da ƙarshen samfurori na wannan dabba na farko a farkon Jurassic.

Juyin halittar waɗannan na farko yana da alaƙa da samun babban kai da ɗan gajeren wuya, an kira su pliosaurians. Za su iya kai tsayin mita 12-15.

sun mallaki lokacin farin ciki, hakora conical, Dole ne mu yi la'akari da su a matsayin masu cin nama da suka mamaye yankunan da suke zaune. Abincinsu ya dogara ne akan sauran dabbobi masu rarrafe na ruwa.

An bi wadannan cryptoclids, inda ƙananan kawuna da wuyoyin elongated suka dawo. Sun fi guntu tsayiMenene ƙari, wuya ya fi tsayin jiki. Za su bayyana a ƙarshen Jurassic kuma za su kasance waɗanda za su fuskanci babban bacewa a ƙarshen Cretaceous.

A daidai lokacin da cryptoclidids suka rayu Elasmosaurs, mafi tsayi na duk plesiosaurs, ya kai mita 17 a tsayi. Kodayake wannan tsayin ya kasance saboda wuyansa. Sun fi girma da nauyi.

Waɗannan manyan nau'ikan nau'ikan guda huɗu suma ana rarraba su a wasu lokuta lokacin gano sabbin samfuran plesiosaur.

Ta yaya aka gano plesiosaurs?

Babban burbushin farko da aka gano a matsayin plesiosaur shine Masana burbushin halittu sun gano a 1821. Mary Anning, ya samo samfurin farko bayan shekaru uku.

An yi musu lakabi da "kusa da kadangaru", abin da ake nufi da plesiosaur ke nan, wanda ya fito daga Girkanci "plesios" (kusa) da "sauros" ( kadangare ko mai rarrafe).

Daga wannan lokacin, An samo plesiosaurs a kowace nahiya, ciki har da Antarctica. Yawancin ragowar da aka samo daga Late Jurassic Oxford Clay Formation (Ingila) ko Tsarin Tsararriyar Niobrara Chalk Formation a Kansas (Amurka).

La Rarraba da aka yanke shawarar ba wa nau'ikan samfurori daban-daban da aka samo sun yi daidai da girma da girman yanayin halittarsu. Kodayake ana ɗaukar wannan matsala, saboda manyan rukuni huɗu ba su da alaƙa da juyin halitta.

na zamani labari plesiosaurs

A farkon labarin mun yi sharhi game da yadda akwai imani cewa plesiosaurs suna ci gaba da rayuwa a yau. An san su ga kowa labarai ko almara game da dodanni na teku, macizai, abubuwan gani a cikin tabkuna, da sauransu… 

Mutane da yawa sun so su danganta waɗannan labarun zuwa wanzuwar plesiosaurs na yanzu. Duk da haka, al'ummar kimiyya sun yi watsi da waɗannan hasashe in babu hujja.

A shekara ta 1977, wani jirgin kamun kifi a kasar Japan ya gano gawar wata dabba mai kafafu, dogayen wuya, da kuma karamin kai. Wannan binciken ya fara ciyar da yiwuwar kasancewar plesiosaurs a cikin ƙasar kuma an ciyar da labarin.

Ko da yake idan za mu yi magana game da shahararrun dodanni na tafkin, Babu wanda ya wuce dodo na Loch Ness. A cikin wannan tafkin daga lokaci zuwa lokaci an ga siffar dabba mai siffar halitta mai kama da na plesiosaur. Ko da yake a wasu lokuta an bayyana shi ta wata hanya dabam dabam.

A wannan yanayin, kuma dole ne mu yi tunanin cewa ruwan tafkin zai yi sanyi sosai don plesiosaurs su zauna a can. Plesiosaur yana shakar iska, don haka za a iya ganin su cikin sauƙi.

da komai, me plesiosaurs ya wanzu ba shi da tabbas, cewa sun ci gaba da wanzuwa a yau wani abu ne da za a tabbatar da shi.