Baculites

***Baculites*** wani barewa ne na heteromorph ammonite cephalopods tare da kusan bawo.Halin,wanda ya rayu a duk duniya a ko'ina cikin mafi yawan Late Cretaceous,kuma wanda a takaice ya tsira daga taron halakar taro na K-Pg,Lamarck ya kira shi a cikin 1799.  

## Rayuwa

### Shell anatomy
Babban harsashi na *Baculites* gabaɗaya madaidaiciya ne kuma yana iya zama ko dai santsi ko tare da ƙwanƙwasa ƙwanƙwasa ko haƙarƙari wanda yawanci yana karkata dorso-zuwa gaba.Budewar itama tana gangara zuwa gaba kuma tana da tazara mai zurfi.An zagaya ta ƙunƙutu zuwa mai ƙarfi yayin da dorsum ya fi faɗi.Harsashin matashin,wanda aka samo a koli,an naɗe shi a cikin ɗaki ɗaya ko biyu kuma an kwatanta shi da minti,kimanin  diamita.Adult *Baculites* sun yi girma daga kusan  (*Baculites larsoni*) har zuwa  a tsayi.

Kamar yadda yake tare da sauran ammonawa,harsashi ya ƙunshi jerin kyamara, ko ɗakuna,waɗanda aka haɗa da dabba ta kunkuntar bututu da ake kira siphuncle wanda za'a iya daidaita abun ciki na iskar gas da kuma buoyancy kamar yadda *Nautilus* yake yi a yau.An raba ɗakunan da bango da ake kira septa.Layin da kowane septum ya hadu da harsashi na waje ana kiransa layin suture ko suture.Kamar sauran ammonawa na gaskiya,*Baculites* suna da tsarin sutura masu rikitarwa a kan bawonsu waɗanda za a iya amfani da su don gano nau'in nau'i daban-daban.

Wani sanannen fasali game da *Baculites* shine cewa mazan na iya zama girman mace kashi uku zuwa rabi kuma mai yiwuwa sun sami haƙarƙari mai sauƙi a saman harsashi.

### Gabatarwa
Halin yanayin yanayin harsashi na *Baculites* tare da tsinkaya striations ko ribbing,irin wannan buɗaɗɗen buɗaɗɗen buɗe ido,kuma mafi ƙunƙuntaccen zagaye zuwa m keel-kamar venter yana nuna kasancewarsa a kwance a rayuwa yana balagagge.Irin wannan nau'in ɓangaren giciye yana samuwa a cikin nautiloids da yawa a baya kamar *Bassleroceras* da *Clitendoceras* daga lokacin Ordovician,wanda za'a iya nuna cewa yana da daidaituwa a kwance.Duk da haka,wasu masu bincike sun kammala cewa Baculites sun rayu a tsaye a tsaye,kai tsaye a rataye,tun da ba su da nauyin kima,motsi ya iyakance ga wannan hanya.Binciken da aka yi kwanan nan,musamman na Gerd Westermann,ya sake tabbatar da cewa aƙalla wasu nau'in *Baculites* a zahiri sun rayu a cikin yanayin kwance ko žasa.

### Ilimin halittu
Daga binciken harsashi isotope,ana tunanin cewa *Baculites* sun zauna a tsakiyar ɓangaren ruwa, ba kusa da ƙasa ko saman teku ba.A wasu wuraren ajiyar dutsen *Baculites* sun zama ruwan dare,kuma ana tunanin sun rayu a cikin manyan tudu.Duk da haka, ba a san su suna faruwa da yawa kamar yadda ake yin dutse ba,kamar yadda wasu batattu,cephalopods masu ruɗi (misali,nautiloids na orthocerid).Nazarin kan samfuran da aka keɓance na musamman sun bayyana radula ta hoton synchrotron. Sakamakon ya nuna cewa *Baculites* sun ci abinci a kan zooplankton pelagic (kamar yadda ragowar gastropod na tsutsa da ƙwanƙwasa ƙwanƙwasa a cikin baki suka nuna).

### Juyin Juyin Halitta
*Baculites* da Cretaceous madaidaiciya ammonite cephalopods sau da yawa suna rikice tare da cephalopods nautiloid na kothocerid kamanni na sama.Dukansu suna da tsayi da tubular a cikin tsari,kuma duka abubuwa ne na yau da kullun don siyarwa a cikin shagunan dutse (sau da yawa a ƙarƙashin sunayen juna).Dukkan zuriyar biyu a bayyane sun samo asali ne daga tsarin tubular da kansu,kuma a lokuta daban-daban a tarihin duniya.Nautiloids na orthocerid galibi sun rayu a baya (na kowa a lokacin Paleozoic Era,mai yiwuwa za su shuɗe a farkon Cretaceous) fiye da *Baculites* (Late Cretaceous/Danian kawai).Ana iya bambanta nau'o'in burbushin halittu guda biyu da siffofi da yawa,mafi bayyane daga cikinsu akwai layin suture:yana da sauƙi a cikin nautiloids na orthocerid kuma an nade shi a cikin *Baculites* da ammonoids masu dangantaka.

## Rarraba nau'ikan