Umhlaba we-paleontology ubulokhu umangalisa, ugcwele izinto ezitholwe izidalwa zangaphambi komlando ezake zazulazula emhlabeni wethu. Muva nje, abacwaningi bathole okutholakele okumangalisayo - iqoqo lamathambo elulwane aneminyaka eyizigidi ezingu-52 ubudala. Amalulwane ayizidalwa ezihehayo osekungamakhulu eminyaka athatha imicabango yabantu. Lezi zidalwa zingompetha esibhakabhakeni sasebusuku, zindiza kalula emoyeni zifuna inyamazane zisebenzisa amakhono azo ayingqayizivele e-echolocation. Lawa mathambo aye anikeza imininingwane ebalulekile ngokuziphendukela kwelulwane futhi aze aveza ngisho nokuba khona kwezinhlobo ezintsha zezilwane. Ukutholwa kuyintuthuko ebalulekile ekuqondeni kwethu lezi zidalwa ezimangalisayo nomlando wazo wokuziphendukela kwemvelo.
Ososayensi bachaze lolu hlobo olusha lwesampula yamalulwane njengamathambo amalulwane amadala kunawo wonke ake alulama. Ucwaningo lwalesi sifanekiso se-paleontological esingasekho, esahlala e-Wyoming eminyakeni engaba yizigidi ezingu-52 edlule, lusekela umbono wokuthi amalulwane ahlukahluka ngokushesha emazwenikazi amaningi ngalesi sikhathi.
Kunezinhlobo ezingaphezu kuka-1,460 zamalulwane atholakala cishe kuzo zonke izingxenye zomhlaba, ngaphandle kwasezindaweni ezisenyakatho neziqhingi ezimbalwa ezikude. E-Green River Formation yase-Wyoming - idiphozithi ephawulekayo yezinsalela zasendulo kusukela ekuqaleni kwe-Eocene - ososayensi bathole izinsalela zamalulwane ezingaphezu kuka-30 kule minyaka engu-60 edlule, kodwa kuze kube manje wonke bekucatshangwa ukuthi amelela izinhlobo ezimbili ezifanayo.
“Amalulwane e-Eocene aziwa eGreen River Formation kusukela ngeminyaka yawo-1960. Kodwa okuthakazelisayo, izibonelo eziningi eziye zaphuma kulokho kwakheka zahlonzwa njengezimelela uhlobo olulodwa, inkomba ye-Icaronycteris, kwaze kwaba cishe eminyakeni engu-20 edlule, lapho kwatholakala uhlobo lwelulwane lwesibili lolunye uhlobo,” kusho omunye umbhali wocwaningo uNancy Simmons. , umnakekeli woMnyango Wezilwane ZaseMnyuziyamu, owasiza ekuchazeni lolu hlobo lwezilwane lwesibili ngo-2008. “Ngangihlale ngisola ukuthi kumelwe ukuba kunezinhlobo zezilwane ezengeziwe lapho.”
Eminyakeni yamuva nje, ososayensi abavela e-Naturalis Biodiversity Centre baqale ukubhekisisa inkomba ye-Icaronycteris ngokuqoqa izilinganiso nolunye ulwazi oluvela ezibonelweni zasemnyuziyamu.
"Izazi ze-paleontology ziqoqe amalulwane amaningi kangaka ahlonzwe njengenkomba ye-Icaronycteris, futhi sazibuza ukuthi empeleni zikhona yini izinhlobo eziningi zezilwane phakathi kwalezi zibonelo," kusho u-Tim Rietbergen, isazi sokuziphendukela kwemvelo e-Naturalis. “Sibe sesifunda ngohlaka lwamathambo olusha olwaphambukisa ukunaka kwethu.”
Uhlaka lwamathambo olugcinwe kahle lwaqoqwa umqoqi wangasese ngo-2017 futhi lwathengwa uMnyuziyamu. Lapho abacwaningi beqhathanisa i-fossil nedathasethi ye-Rietbergen enwetshiwe, yabonakala ngokucacile njengohlobo olusha. Uhlaka lwamathambo lwesibili lwamathambo olwatholwa endaweni efanayo ngo-1994 futhi emaqoqweni eRoyal Ontario Museum nawo ahlonzwa njengalolu hlobo olusha. Abacwaningi banikeze lezi zinsalela igama elithi “I-Icaronycteris gunnelli” ngokuhlonipha u-Gregg Gunnell, isazi sesayensi yezinto eziphilayo saseDuke University owashona ngo-2017 futhi wenza igalelo elibanzi ekuqondeni amalulwane ezinsalela kanye nokuziphendukela kwemvelo.
Ngokusho kwabacwaningi, abasanda kutholakala I-Icaronycteris gunnelli yayincane kakhulu, inesisindo esingamagremu angu-25 kuphela, okulingana namamabula amahlanu. Naphezu kobukhulu bayo obuncane, yayisivele yashintsha ikhono lokundiza futhi kungenzeka ikwazi ukusebenzisa i-echolocation. Cishe ilulwane lalihlala ezihlahleni ezizungeze ichibi futhi lizingela izinambuzane ngokundiza phezu kwamanzi.
UMatthew Jones, umcwaningi emkhakheni we-paleontology e-Arizona State University futhi ongomunye wababhali balolu cwaningo, usikisela ukuthi amalulwane ayinzalo yezilwane ezincelisayo ezincane ezidla izinambuzane ezazihlala ezihlahleni. Kodwa-ke, ukuhlonza izinhlobo zezilwane ezincelisayo ezincane ezihlobene namalulwane kuyinselele ngenxa yokuba khona kwezinhlobo eziningi ezahlukene. Ngaphezu kwalokho, iningi lalezi zinhlobo zezilwane ezincelisayo zijwayele kuphela ngokutholakala okulinganiselwe kwamazinyo nemihlathi yazo.
Izinsalela ze-Fossil Lake ze-Green River Formation zibhekwa njengezingavamile ochwepheshe ngoba izingqimba ze-limestone ezacile zephepha zakhiwa ngaphansi kwezimo eziyingqayizivele ezazilondoloza ngokuphumelelayo noma yini eyayicwila phansi echibini.
Amathambo atholakala e-Wyoming akhombisa ukuthi angawenkathi yokuqala ye-Eocene. Ngalesi sikhathi, izinga lokushisa loMhlaba laliqala ukufudumala, futhi izilwane, izinambuzane, nezitshalo kwakusakazeka ngokushesha futhi kuhlukahluka. Amalulwane atholakala e-Fossil Lake afana namalulwane esinawo namuhla, aneminwe emide esetshenziselwa ukubamba ulwelwesi lwamaphiko awo.
Izinsalela zamalulwane ezisanda kutholwa zinokuningi okufanayo namalulwane esimanje kodwa futhi zinezici ezithile ezihlukile. Omunye wale mehluko ukuthi amathambo amalulwane asanda kutholwa, ikakhulukazi ezithweni zawo zangemuva, anamandla kakhulu futhi aqine kakhulu. Kuchaza uRietbergen, umcwaningi oholayo wocwaningo.
Ezikhathini zanamuhla, amalulwane ngokuvamile anamathambo azacile futhi angasindi asiza emandleni awo okundiza. Kodwa-ke, uhlobo lwamalulwane olusanda kutholwa lunemilenze yangemuva eqinile, okungase lusikisele ukuthi luzuze njengefa izici kokhokho balo. Lokhu kusho ukuthi la malulwane ayenemilenze eqinile yokuqwala ezihlahleni.
Ngaphezu kwalokho, uhlobo lwamalulwane olusanda kutholwa lwalunozipho emunweni walo wokukhomba ngaphezu kwesithupha. Amalulwane amaningi namuhla anozipho lwesithupha oluwasiza ukuba abheke phezulu ngesikhathi elele. Lolu lwazi olusha luphakamisa ukuthi amalulwane asuka kulesi sikhathi angaba yisigaba sokugcina soguquko ukusuka kwabaqwali kuya kumandiza ochwepheshe.
Ucwaningo lwashicilelwa okokuqala kujenali I-PLOS ONE. Ephreli 12, 2023.
