Izirhubuluzi Zamandulo Ezahlukahlukeneyo Ngokumila Nangobukhulu
KUZO zonke iintlobo zezinto eziphilayo ngoku ezingasekhoyo, mhlawumbi izirhubuluzi zamandulo ziye zazixhokonxa ngokonakona iingcinga zabantu. Ngokufuthi izirhubuluzi zamandulo zithelekelelwa njengezinkulu nezoyikekayo. Xa eli gama labhalwayo okokuqala lisuka kumagama esiGrike athetha “icilikishe eloyikekayo,” zazicingelwa njengezinkulu ngokoyikekayo ngenxa yokuba iifosili zezirhubuluzi zamandulo ezazisaziwa ngoko zazinkulu.
Zimbi iintlobo zezirhubuluzi zamandulo zazinkulu ngokugqithiseleyo ibe zazibonakala zisoyikeka, ngokunokwenzeka zinobukhulu obuphindaphindwe ngaphezu kwezihlandlo ezilishumi kunobendlovu enkulu yaseAfrika. Noko ke, kumashumi eminyaka edluleyo, izazinzulu ngezidalwa zamandulo ziye zavumbulula amathambo ezirhubuluzi zamandulo ezininzi ezincinane. Zimbi zinobukhulu obungangobembongolo, ibe zimbi zazo zingenkulu kuyaphi kunentshontsho lenkuku! Makhe sihlolisise ezinye zezi zirhubuluzi zamandulo zinomtsalane.
Amacilikishe Abhabhayo
Olunye uhlobo olubangel’ umdla lwamacilikishe amandulo yayiyipterosaur (“icilikishe elinamaphiko”), eliquka ipterodactyl (“umnwe onamaphiko”). Kodwa la ayengezizo izirhubuluzi zamandulo, engezizo neentaka. Yayingamacilikishe abhabhayo ibe akuluhlu lwezinye izirhubuluzi ezinjengeedinosaurs neengwenya. Zimbi zazo zazinamaphiko anobude obungangeemitha ezisibhozo. Esinye esafunyanwa eTexas ngowe-1975 sibonisa ukuba zimbi zazinamaphiko anobude obungaphezu kweemitha ezili-15. Kunokwenzeka ukuba ezi zazizezona zilwanyana zikhulu kwezakha zabhabha.
Ngoxa loo macilikishe anamaphiko ayenamazinyo, ukhakhayi, amarhorho neenyawo zangasemva zesirhubuluzi, ayengazifanekiseli nangayiphi na indlela izirhubuluzi eziziidinosaurs. Ibe ngoxa zazikhangeleka njengentaka enamaphiko awomeleleyo nalungiselelwe ukujamelana nomoya, zazahluke mpela kwiintaka. Njengeentaka, amacilikishe anamaphiko ayenamathambo anemingxuma ngaphakathi namalungu abhetyebhetye ezimpikweni angenanto. Noko ke, amaphiko entaka aneentsiba kunokuba abe nenwebu njengoko kwakunjalo ngamacilikishe anamaphiko. Ibe umnwe wesine wemilenze yangaphambili yecilikishe elinamaphiko wawusiba mde ukuze uxhase inwebu yephiko. Entakeni umnwe wesibini nguwo olixhasa ngokuyintloko iphiko.
Iiornithischians
Iiornithischians (“intaka enamahleza”) zazizezinye zeendidi ezimbini eziqhelekileyo zezirhubuluzi zamandulo njengoko oko kwakuboniswa yindlela amile ngayo amahleza azo. Ezo zazikolu didi zazinamahleza afana nawentaka kodwa, kakade ke, zinkulu ngokugqithiseleyo. Zimbi zazincinane, ezinye zinkulu. I-iguanodon yayifikelela kubude obungangeemitha ezisithoba. Amathambo eentlobo ezininzi zeehadrosaurs abonisa imihlathi yangasentla neyangasezantsi yomlomo wentaka enamazinyo amaninzi. Kuyabonakala ukuba iihadrosaurs zazinemilenze emibini, zihamba okanye zibaleka ngemilenze emibini. Zimbi zazo zazifikelela kubude obungangeemitha ezili-10.
Iistegosaurs zaziliqela leeornithischians ezazinamathambo awomeleleyo alandelelanayo namile kakuhle emqolo. Zazihamba ngemilenze yazo yomine ibe zazimalunga neemitha ezintandathu ubude, neemitha ezisisi-2,4 ukuphakama emahlezeni. Kutshanje, kuye kwacingwa ukuba amathambo asemqolo ayesebenza kungekuphela nje ekuzikhuseleni kodwa njengenxalenye yenkqubo epholisa imizimba yazo. Imilenze yangasemva yayimikhulu yaye ifana neyendlovu, ngoxa imilenze yangaphambili yayimincinane, ibangela ukuba intloko encinane ibe sezantsi emhlabeni. Umsila wawuneenzipho ezinde, ezingamathambo ezenze isangqa ngasemva.
Uhlobo lokugqibela lweeornithischians—elalisasazeke kuwo wonke umhlaba—yayilelo lweeceratopsians, okanye izirhubuluzi zamandulo ezineempondo. Zazisusela kubude obuziimitha ezisisi-1,8 ukuya kwiimitha ezisibhozo. Ngokufanayo nomkhombe waseAfrika, ezi zirhubuluzi zazomelele “okwenqwelo” ezinkulu nezinqatyisiweyo zemfazwe zikhakhayi olukhulu ngokungathi likhaka lentamo. Uhlobo oluneempondo ezintathu itriceratops, lwaluqhelekile phakathi kwezirhubuluzi zamandulo. Iimpondo ezimbini ezingaphezu kwamehlo zazikhula de zifikelele kubude obungangeemitha ezisisi-0,9. Iifosili ezininzi zetriceratops ziye zavunjululwa kwintlambo yoMlambo iRed Deer eAlberta.
IiSaurischians—Izirhubuluzi Eziziingxilimbela Zamandulo
Olunye udidi oluqhelekileyo lwezirhubuluzi zamandulo lwaziwa njengeesaurischians (“amacilikishe anamahleza”), zinamahleza afana nalawo amacilikishe, nangona, kwakhona, zizikhulu ngokugqithiseleyo. Kubonakala ngathi zineempawu ezifanayo nezezirhubuluzi zamandulo eziqhelekileyo: zinkulu yaye ziyoyikeka. Olunye uhlobo lwazo lwaluyiapatosaurus (ngaphambili eyayibizwa ngokuba yibrontosaurus), isirhubuluzi samandulo esasisitya utyani nesasihamba ngemilenze emine. Sasifikelela kubude obuziimitha ezingama-21 nakubunzima obabuthelekelelwa buziitoni ezingama-30. Ezi zirhubuluzi zamandulo ziye zavunjululwa kuMntla Merika naseYurophu.
Isirhubuluzi esiyingxilimbela elingana nezo esiyidiplodocus sasifana nenyoka, sinentamo nomsila omde kodwa sinemilenze. Sesona sirhubuluzi samandulo side kwezaziwayo, sinobude obuziimitha ezingama-27, nangona sinobunzima obungaphantsi kancinane kobo beapatosaurus. Idiplodocus eyafunyanwa kuMntla Merika, yayinamathatha ngaphezu kwentloko yayo, awayeyenza ikwazi ukuntywilisela phantse yonke intloko yayo emanzini.
Kwandula ke kubekho ibrachiosaurus. Isakhelo somzimba esingamathambo esafunyanwa eTanzania safikelela kubude obuziimitha ezingama-21. Kuqikelelwa ukuba ezinye zazo zazinobunzima obungaphezu kweetoni ezingama-85. Xa zimile zinobude obuziimitha ezili-12 ukuphakama, zinomzimba owehlele ngasemsileni, zifana nendlulamthi.
Ngowe-1985 kwavunjululwa iifosili zamathambo omqolo ezazinobukhulu obungaqhelekanga eNew Mexico eUnited States of America. Umgcini weMyuziyam Yezidalwa Zamandulo yaseNew Mexico wayibiza ngokuba yiseismosaurus. Esi silwanyana kwakuqikelelwa ukuba simalunga neemitha ezingama-30 ubude yaye sinobunzima mhlawumbi obufikelela kwiitoni ezilikhulu!
Ityrannosaurus rex ebonakala inoburhalarhume (“ukumkani wamacilikishe oneengcwangu”) yayimalunga neemitha ezintathu ubude emahlezeni. Xa imile, yayinokuba nomlinganiselo omalunga neemitha ezintandathu ukuphakama. Yayinokuba malunga neemitha ezili-12 ubude. Intloko yayo yayifikelela iimitha ezisisi-1,2 ubude ibe umlomo wayo omkhulu wawunamazinyo amaninzi amile okombhumbulu anobude obuziisentimitha ezili-15. Imilenze yangasemva yayifana neyendlovu, ngoxa imilenze yangaphambili yayimincinane kakhulu. Yayixhathisa ngomsila omkhulu ofana nowecilikishe xa iphakama. Kunokuhamba zimi nkqo, ngoku kugqitywe kwelokuba iityrannosaurs ziyimisa imizimba ngokuthe tyaba, zixhathisa ubunzima bemizimba yazo ngemisila yazo emide.
Ukuguquka Kwezinto
Ukuba izirhubuluzi zamandulo zazikho ngobuninzi bazo emhlabeni wonke, kwimbonakalo yomhlaba yamandulo eyathi shwaka kude kudala, kububungqina obuvela kwingxelo yeefosili. Kodwa ezi zidalwa zimangalisayo, ndawonye nezinye iintlobo zezilwanyana nezityalo ezingenakubalwa, zaphel’ emehlweni. Ngokuphathelele ixesha kanye ezenzeka ngalo ezi zinto, isazinzulu ngezidalwa zamandulo uD. A. Russell uchaza esithi: “Ngelishwa, iinkqubo ezikhoyo zokulinganisela ubude bexesha ezenzeka ngalo ezi ziganeko zakudala kangaka noko azichananga kangako.”
Kwenzeka ntoni kwizirhubuluzi zamandulo? Ukuvela kwazo ngequbuliso nokuphela kwazo ngequbuliso kuthetha ntoni? Ngaba izirhubuluzi zamandulo zenza ukuba siyithandabuze imigaqo ethile ngemfundiso kaDarwin yendaleko? Loo mibuzo siza kuyiphonononga kwinqaku elilandelayo.
[Umzobo okwiphepha 8, 9]
(Ukuba ufuna inkcazelo ehlahlelwe kakuhle, yiya kwimpapasho)
Iimitha ezisithoba
Iimitha ezintandathu
Iimitha ezintathu