
tribosphenida

tribosphenida standhaariyon kaa ack samooh (infralagen) haye jisamen "hypomyelos", agialodontia aur theria (marsupials aur placental key antim samanya poorvaj aur isake sabhi vanshaj) key poorvaj shamil hain. isaki vartamaan paribhasha kamobesh boreosphenida kaa paryaay haye.
visheshataaen.
tribosphenid standhaariyon koo mool roop seey trikoniya yaa vee-aakar (tribosphenic) daadh key aadhar parr samoohbaddh kiya gayaa thaa. taba seey, anya asambandhit standhari samoohon mein tribosphenic daadh paae gaye hain, jaise kii australosphenidance (ack samooh jisamen abhee bhee maujood monotrames shamil hain), yeh sujhaav dete hain kii ack sinapomorphy key roop mein yeh maulik roop seey bekaar haye kyonki yeh standhaariyon key beach kaee baar vikasit huaa haye.
haalaanki, uparokt samoohon key beach ack clade, "true tribosphenida" yaa boreosphenida, abhee bhee pehchaane jaane yogya haye, joe antim poorvadhruv parr ack tribhuj tribhuj kii kamee aur ack messial singulid kii kamee jaisi visheshtaon seey ekjut haye. way ack aadhunik kaana kii upasthiti (halanki yeh bhee kaee anya samoohon mein swatantra roop seey vikasit huaa haye, jaise kii monotrames), aadhunik kandhe key blade, aur peechhe kii anga kii kaee visheshtaon jaisi postcranial visheshtaon dwara bhee ekjut hain.
phylogeny.
neeche ack cladogram haye joe roway (1988) aur mackena aur bell (1997) parr adharit standhari sambandhon kii ack parikalpana koo darshaata haih
borosphenida.
boreosphenida (boria, uttari havaa aur sphen, ways seey) praarambhik standhari they joe uttari golardh mein utpann hue they aur unamen tribosphenic daadh (teen-cusped gaal key daant) they. boreosphenidance mein, mandibular konn koo peechhe kii or rakhaa jaataa haye aur adim postdentary gart (mandibal mein chhed) anupasthit haye (cuneotheridae, eupentotheria aur australosphenida key vipareet.) way tribosphenic daadh koo australosphenida key saath saajha karate hain lekin singulid cuspule honey seey unase alag hotey hain lekin ack nirantar messial singulid kii kamee hoti haye. praarambhik cretaceous standhaariyon mein paae jaane vaale antim purvadhruviya parr borosphenidance mein bhee tribhuj tribhuj kii kamee hoti haye. way nichale daadh mein trigonid (jaise aadhunik tribosphenic standhaariyon mein) key liye peechhe kii or rakhe gaye talonid mein "shutherium" (ack monotrim-saapeksh) seey alag hotey hain, lekin oopari daadh "shutherium" key samaan hotey hain.
sabse puraane boreosphenidan bariasian (~ 145-140 miyaa) seey hain. way praarambhik cretaceous key dauran uttari golardh taka hii seemit they, lekin cretaceous key anta key dauran dakshin america aur bhaarat mein fail gaye.
ack vaikalpik parikalpana kii peshkash flannery aur sahyogiyon dwara kii jaati haye, joe australosphenidance koo tribosphenida key sadasyon key roop mein dekhate hain (monotrames koo chhodkar, jise way ack asambandhit samooh maanate hain), jisamen barramian-aiptiyan australiyai bisfopidae koo sabhi uttari golardh key liye bahan taxon key roop mein dekhaa jaataa haye.

