Rekonstruksi artis Gangtocunia aspera tina kahirupan dasar laut Cambrian kira-kira 514 juta taun ka tukang. Bagian tina tulang tunggal dina latar hareup dipiceun pikeun nembongkeun tumor lemes dina tulang.Kiridit: Wang Xiaodong Rekonstruksi
Élmuwan tungtungna tiasa ngaungkabkeun misteri anu umurna berabad-abad ngeunaan évolusi kahirupan di Bumi, ngungkabkeun kumaha rupa sato anu mimiti nyieun tulang. Papanggihan ieu dibantuan ku koleksi fosil anu dilestarikan anu aya di propinsi Yunnan wétan di Cina.Papanggihan diterbitkeun 2 Nov dina jurnal ilmiah Prosiding Royal Society B.
Dina hiji kajadian anu disebut Ledakan Cambrian kira-kira 550 nepi ka 520 juta taun ka tukang, sato pangheulana ngawangun tulang anu kuat sarta tahan banting muncul dina catetan fosil, sakedap panon dina waktu géologis. Seueur fosil awal ieu mangrupikeun tabung kerung sederhana anu panjangna ti sababaraha milimeter dugi ka sababaraha séntiméter. Sanajan kitu, jenis sato nu ngawangun tulang ieu ampir sakabéhna kanyahoan, sabab kakurangan bagian lemes diperlukeun pikeun ngaidentipikasi aranjeunna salaku bagian tina fauna utama masih hirup kiwari.
Spesimen fosil (kénca) jeung skématik (katuhu) Gangtoconia aspera ngajaga jaringan lemes, kaasup peujit jeung tentakel.Kiridit: Luke Parry sareng Zhang Guangxu
Opat sampel ti Gangtoko of Aspera Jaringan lemes na tetep gembleng, kaasup peujit sarta mouthparts, sarta eta milik grup anyar fosil dating deui 514 juta taun. Ieu nunjukkeun yén sungut spésiés ieu dikurilingan ku cingcin lemes, cakar teu bercabang panjangna kira-kira 5 mm (0,2 inci). Kamungkinan ieu dianggo pikeun nyeureud sareng nangkep mangsa, sapertos artropoda leutik.Excavations ogé némbongkeun Gund Anjeunna boga cecum (muka ngan dina hiji tungtung) nu ngabagi kana lumen nu ngeusi panjang tabung.
Fitur-fitur ieu henteu kapendak dugi ka ayeuna dina ubur-ubur modern, anemone laut sareng barayana anu disebut cnidaria, anu bagian lemesna jarang pisan dina catetan fosil. Panalungtikan némbongkeun yén sato basajan ieu diantara nu pangheulana ngawangun skeletons padet nu nyusun lolobana catetan fosil dipikawanoh.
Numutkeun peneliti, Gund Sigana sarupa jeung ubur-ubur scyphozoan modern, kalawan struktur tubular kaku napel substrat. sungut tentacle urang nempel kaluar tina tabung, tapi bisa ditarik pikeun nyingkahan prédator.Tabung dibandingkeun polyps jellyfish hirup Gund Dijieun tina kalsium fosfat, mineral teuas nu ngawangun huntu jeung tulang urang. Kana waktu, pamakéan bahan ieu pikeun ngawangun tulang geus jadi kirang umum di sato.
A nutup-up tina sungut Tuconia aspera Gang, némbongkeun tentacles nu bisa dipaké pikeun nyekel mangsa.Kiridit: Luke Parry sareng Zhang Guangxu
Panulis pakait Dr Luke Barry, Departemen Élmu Bumi,[{” attribute=””>University of Oxford, said: “This really is a one-in-million discovery. These mysterious tubes are often found in groups of hundreds of individuals, but until now they have been regarded as ‘problematic’ fossils, because we had no way of classifying them. Thanks to these extraordinary new specimens, a key piece of the evolutionary puzzle has been put firmly in place.”
The new specimens clearly demonstrate that Gangtoucunia was not related to annelid worms (earthworms, polychaetes and their relatives) as had been previously suggested for similar fossils. It is now clear that Gangtoucunia’s body had a smooth exterior and a gut partitioned longitudinally, whereas annelids have segmented bodies with transverse partitioning of the body.
The fossil was found at a site in the Gaoloufang section in Kunming, eastern Yunnan Province, China. Here, anaerobic (oxygen-poor) conditions limit the presence of bacteria that normally degrade soft tissues in fossils.
Fossil specimen of Gangtoucunia aspera preserving soft tissues, including the gut and tentacles (left and middle). The drawing at the right illustrates the visible anatomical features in the fossil specimens. Credit: Luke Parry and Guangxu Zhang
PhD student Guangxu Zhang, who collected and discovered the specimens, said: “The first time I discovered the pink soft tissue on top of a Gangtoucunia tube, I was surprised and confused about what they were. In the following month, I found three more specimens with soft tissue preservation, which was very exciting and made me rethink the affinity of Gangtoucunia. The soft tissue of Gangtoucunia, particularly the tentacles, reveals that it is certainly not a priapulid-like worm as previous studies suggested, but more like a coral, and then I realised that it is a cnidarian.”
Although the fossil clearly shows that Gangtoucunia was a primitive jellyfish, this doesn’t rule out the possibility that other early tube-fossil species looked very different. From Cambrian rocks in Yunnan province, the research team has previously found well-preserved tube fossils that could be identified as priapulids (marine worms), lobopodians (worms with paired legs, closely related to arthropods today), and annelids.
Co-corresponding author Xiaoya Ma (Yunnan University and University of Exeter) said: “A tubicolous mode of life seems to have become increasingly common in the Cambrian, which might be an adaptive response to increasing predation pressure in the early Cambrian. This study demonstrates that exceptional soft-tissue preservation is crucial for us to understand these ancient animals.”
Reference: “Exceptional soft tissue preservation reveals a cnidarian affinity for a Cambrian phosphatic tubicolous enigma” by Guangxu Zhang, Luke A. Parry, Jakob Vinther and Xiaoya Ma, 2 November 2022, Proceedings of the Royal Society B Biological Sciences.
DOI: 10.1098/rspb.2022.1623