Gwawinapterus

Gwawinapterus
Scientific classification
Kingdom	Animalia
Phylum	Chordata
Class	Actinopteri (mul)
Order	Ichthyodectiformes (mul)
Dangi	Saurodontidae (mul)
genus (en)	Gwawinapterus ,

Gwawinapterus beardi wani nau'in kifi ne mai laushi daga zamanin Late Cretaceous na British Columbia, Kanada . Duk da yake da farko an bayyana shi a matsayin memba mai rai na iyali pterosaur Istiodactylidae, ƙarin bincike ya jefa shakku game da gano samfurin a matsayin pterosaor, kuma binciken da aka buga a 2012 ya gano ragowar kamar yadda ta fito ne daga kifin Saurodontid"

Bayyanawa

Gwawinapterus beardi an san shi taga samfurin burbushin halittu guda ɗaya, wanda ya ƙunshi rabin gaba na kwanyar (na sama da na ƙasa). Ƙarshen hanci yana da zagaye kuma yana da zurfi tare da tsawo na kimanin 9.5 centimeters (3.7 in). Tushen yana da kimanin 6.5 centimeters (2.6 in) daga gefen gaba na babbar buɗewar kwanyar, ko fenestra. A ƙasa da wannan buɗewar Maƙarƙashiya ta sama tana da kimanin 21 millimeters (0.83 in) tsawo. Da farko an ba da shawarar cewa jaw ɗin ya zama haɗin kai na premaxilla da maxilla na dabba mai rarrafe. Kowane jaw na sama yana riƙe da akalla hakora 26, goma sha ɗaya ko goma sha biyu daga cikinsu a ƙasa da fenestra; ba a adana gaban layin hakora ba kuma burbushin ya karye a ƙarshen sa. Hanci suna cike sosai. Gwanin hakora ƙananan ne, 4 millimeters (0.16 in) tsawo da 2.75 millimeters (1.108 in) fadi, shimfiɗa, da kuma triangular tare da gefuna masu lankwasawa. Yankunan ba su da tsayi, amma suna da zagaye. Hanci suna da madaidaiciya sosai, ba su nuna wani karkata zuwa ko dai baya ko tsakiya ba. Tushen hakora guda ɗaya sun fi tsayi, kimanin 10 zuwa 12 millimeters (0.39 zuwa 0.47 in), don jimlar tsawon hakora kusan 14 millimeters0.55 in).

Masu bayyana sun gano siffofi guda biyu na musamman (autapomorphies): adadi na fiye da hakora 25 a cikin jaw na sama da tushen hakora fiye da sau biyu kamar kambi.

Bincike da ganewa

A watan Mayu na shekara ta 2005, masanin burbushin halittu Sharon Hubbard ya sami dutse tare da ƙasusuwa da hakora a kan rairayin bakin teku kusa da Collishaw Point a Tsibirin Hornby, British Columbia, Kanada. Tare da ita akwai Graham Beard, Shugaban Ƙungiyar Gidan Tarihi na Paleontology na Tsibirin Vancouver da ke Qualicum Beach, wanda ya ƙara burbushin a cikin tarinsa. Beard ya jawo hankalin masanin ilmin burbushin halittu Philip J. Currie. Shi kuma ya sami taimakon abokin aikinsa Victoria M. Arbour wanda ya gano samfurin a matsayin pterosaur wanda ba shi da ƙwarewa a fannin kimiyya.

A cikin 2011, Arbour da Philip J. Currie sun bayyana samfurin a matsayin nau'in nau'in Gwawinapterus beardi. Sunan ya samo asali ne daga Gwa'wina, ma'ana "Ravens" a cikin Kwak'wala, harshen Kwakwaka'wakw, dangane da kamanceceniyar kwanyar tare da kawunan kwari na masks na hamatsa na wannan kabilar, da kuma Latinised Greek pteron, "fuka-fuki". takamaiman suna yana girmama Beard.

An yanke dutsen a kashi biyu don ingantaccen karatu kuma rabi, tare da lambobin kaya VIPM 1513a da VIPM 1513b, suna wakiltar holotype. Wataƙila ya samo asali ne a cikin nau'ikan ruwa na Tsarin Northumberland wanda ya kasance a ƙarshen matakin Campanian, daga kimanin shekaru miliyan saba'in da suka gabata.  

Dutse, ƙuƙwalwar calcite, tana da tsawon kusan 20 centimeters (7.9 in). Yana riƙe da hanci na samfurin, wanda aka gano shi ne na farko na kwanyar pterosaur da aka samu a Kanada. Wasu daga cikin farfajiyar ƙashi suna bayyane; wani ɓangare an adana shi azaman ɓangaren giciye ko a matsayin alamar. Kayan kambi na hakora da suka fashe sun ɓace amma har yanzu akwai suturar hakora kuma saboda lalacewar hakora da maye gurbin hakora suna bayyane.

An sanya Gwawinapterus zuwa Istiodactylidae, ta amfani da hanyar kwatankwacin jikin mutum. Idan aka kwatanta da kwanyar istiodactylid Istiodactylus sinensis, an kiyasta fuka-fukan Gwawinapterus a mita uku. Marubutan sun lura cewa a matsayin pterosaur, zai zama mafi ƙanƙanta da aka sani na istiodactylid da shekaru miliyan arba'in kuma shine kawai sanannen pterosaor mai hakora daga Late Cretaceous. Wannan zai nuna cewa bambancin pterosaur ya ragu ƙasa da yadda aka ɗauka a baya a lokacin Cretaceous.

Duk da haka, binciken da aka yi daga baya ya haifar da shakku kan gano samfurin a matsayin pterosaur. A cikin wani bincike na 2012 game da kwanyar istiodactylid, Mark Witton ya lura cewa kwanyar Gwawinapterus ta nuna wani yanayi na maye gurbin hakori mai ban mamaki, tare da sabbin haƙoran maye gurbin da ke tsiro kai tsaye a kan tsofaffin haƙoran. Wannan ɓangaren na ilimin halittarsa ​​ba a san shi ba a cikin kowace pterosaur. Witton ya bayyana cewa wannan "bambancin asali yana tambaya game da yanayin pterosaurian na Gwawinapterus, kuma yana iya nuna cewa istiodactylids sun kasance ƙungiya da aka sani musamman daga Ƙananan Cretaceous." Wani cikakken sake dubawa na samfurin, wanda aka buga a cikin 2012, ya ba da shawarar cewa samfurin a zahiri ba pterosaur ba ne amma ya fito ne daga nau'in kifi Saurodontid. [yanawa da ake buƙata]