'Izilwane ezidumayo' ezinjengobhejane zakhula zaba zinkulu ngokucwayiza kweso ngemva kokushona kwama-dinosaurs

Ukushabalala kwama-dinosaur kwakuyisenzakalo esiyinhlekelele namanje esisagubuzelwe yimfihlakalo. Kodwa okuthakazelisa nakakhulu yilokho okwenzeka ngemva kokushabalala. Kuvele ukuthi izilwane ezincelisayo ezisinde kulo mthelela zakhula kahle ngemuva kwalokho, ikakhulukazi iqembu lezihlobo zamahhashi afana nobhejane.

Ngokushesha zakhula zaba ngamasayizi amakhulu, zaziwa ngokuthi “izilwane ezidumayo”. Kwenzeka kanjani lokhu ngokushesha okungaka? Impendulo ilele ekushayweni kombani kokuziphendukela kwemvelo okwenzeka embusweni wezilwane ngemuva komthelela we-asteroid, ngokusho kocwaningo olusha olwanyatheliswa ngoMeyi 11 endaweni. iphephabhuku Isayensi.

Okutholakele kusikisela ukuthi ubukhulu bomzimba omkhulu bunikeze okungenani ezinye izilwane ezincelisayo ngenzuzo yokuziphendukela kwemvelo ngemva kokushabalala kwama-dinosaurs.

Izilwane ezincelisayo ngokuvamile zazigijima ezinyaweni zama-dinosaurs amakhulu kakhulu ngesikhathi se-Cretaceous (eminyakeni eyizigidi ezingu-145 kuya kwezingu-66 edlule). Abaningi babengaphansi kwamaphawundi angu-22 (amakhilogremu angu-10).

Nokho, njengoba ama-dinosaurs eshabalala, izilwane ezincelisayo zabamba ithuba eliyisihluthulelo lokukhula. Bambalwa abasifeza kanye ne-brontotheres, inzalo yesilwane esincelisayo esangasekho esasinesisindo esingamakhilogremu angu-40 lapho sizalwa futhi sihlobene kakhulu namahhashi amanje.

Ngokombhali wokuqala walolu cwaningo u-Oscar Sanisidro, umcwaningi weGlobal Change Ecology and Evolution Research Group eNyuvesi yase-Alcalá eSpain, amanye amaqembu ezilwane ezincelisayo athole amasayizi amakhulu ngaphambi kokuba afinyelele, ama-brontotheres ayeyizilwane zokuqala ezifika njalo ezinobukhulu obukhulu.

Akugcinanga lapho, bafinyelele isisindo esiphezulu samathani angu-4-5 (3.6 kuya ku-4.5 metric tons) eminyakeni eyizigidi ezingu-16 nje kuphela, isikhathi esifushane ngokombono we geological.

Izinsalela zikaBrontotheres ziye zatholakala endaweni manje ebizwa ngokuthi iNyakatho Melika, futhi bathola incwadi ethi “Thunder Beast” emalungwini esizwe samaSioux, ayekholelwa ukuthi lezi zinsalela zazivela “kumaHhashi Amakhulu Eduma,” ayezulazula emathafeni ngesikhathi sokuduma kwezulu.

Izazi ze-paleontologists phambilini zaqaphela ukuthi i-brontotheres yakhula ngokushesha. Inkinga ukuthi bebengenayo incazelo ebambekayo yokuthi kanjani kuze kube namuhla.

Iqembu kungenzeka ukuthi lithathe enye yezindlela ezintathu ezahlukene. Omunye umbono, owaziwa ngokuthi umthetho we-Cope, uphakamisa ukuthi lonke iqembu kancane kancane lakhula ngobukhulu ngokuhamba kwesikhathi, kufana nokugibela izitebhisi ezizihambelayo ukusuka kwencane ukuya enkulu.

Enye inkolelo-mbono iphakamisa ukuthi esikhundleni sokwanda okuqhubekayo ngokuhamba kwesikhathi, kube nezikhathi zokwanda okusheshayo okwakuzokhuphuka ngezikhathi ezithile, kufane nokugijima ukugibela izitebhisi kodwa ukuma ukuze uthole ukuphefumula kwakho lapho uhlala khona.

Ithiyori yesithathu yayiwukuthi kwakungekho ukukhula okungaguquki kuzo zonke izinhlobo zezinto eziphilayo; abanye benyuka, abanye behla, kodwa ngokwesilinganiso, abaningi bagcina sebebakhulu kunokuba babe bancane. U-Sanisidro nozakwabo bakhethe isimo okungenzeka kakhulu ngokuhlaziya isihlahla somndeni esihlanganisa abantu abangu-276 abaziwayo be-brontothere.

Bathole ukuthi i-hypothesis yesithathu ilingana kangcono nedatha: esikhundleni sokuthi kancane kancane ikhule ibe nkulu ngokuhamba kwesikhathi noma ukuvuvukala nokukhuphuka, uhlobo olulodwa lwe-brontothere lungakhula lube lukhudlwana noma lunciphe njengoba lunwetshwa lube yizindawo ezintsha zemvelo.

Akuzange kuthathe isikhathi eside ukuba kuvele uhlobo olusha emlandweni wezinsalela. Kodwa-ke, izinhlobo ezinkulu zasinda ngenkathi ezincane zaphela, okwandisa usayizi weqembu ngokuhamba kwesikhathi.

NgokukaSanisidro, impendulo ezwakalayo ukuncintisana. Ngenxa yokuthi izilwane ezincelisayo zazincane phakathi naleyo nkathi, kwakunokuncintisana okukhulu phakathi kwezilwane ezidla uhlaza ezincane. Ezinkudlwana zazinokuncintisana okuncane ngemithombo yokudla ezazikufuna, okuzinikeza ithuba eliphakeme lokusinda.

UBruce Lieberman, isazi se-paleontologist wase-University of Kansas owayengahlangene nalolu cwaningo, utshele i-Live Science ukuthi uhlabeke umxhwele ngobunkimbinkimbi bocwaningo.

Ubunkimbinkimbi bokuhlaziywa kwathinta uBruce Lieberman, isazi sesayensi yezinto eziphilayo eNyuvesi yaseKansas owayengahileleki ocwaningweni.

U-Sanisidro uveza ukuthi lolu cwaningo luchaza kuphela ukuthi izidalwa ezinjengobhejane zaba kanjani imidondoshiya, kodwa uhlela ukuhlola ukufaneleka kwemodeli yakhe kwezinye izinhlobo zezilwane ezincelisayo ezinkulu esikhathini esizayo.

"Futhi, singathanda ukuhlola ukuthi izinguquko kusayizi womzimba we-brontothere zingaba nomthelela kanjani kwezinye izici zalezi zilwane, njengezilinganiso zogebhezi, ukuba khona kwama-appendages amathambo," njengezimpondo, kusho uSanisidro.

Kuyamangaza ukucabanga ngezinguquko ezisheshayo ezenzeka ezilwaneni ngemva kwalezi zinhlekelele. Ukuvela kwalezi zinhlobo zezilwane kuyisikhumbuzo sokuguquguquka okumangalisayo kokuphila eMhlabeni nokuthi umhlaba ungashintsha kakhulu kangakanani ngemizuzwana nje embalwa.

Ucwaningo lwashicilelwa ekuqaleni ku iphephabhuku Isayensi ngoMeyi 11, 2023.