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歷史

這個部(bu)分脊(ji)(ji)椎(zhui)的(de)(de)保存(cun)狀況很差，但卻異常(chang)的(de)(de)巨(ju)大(da)和(he)寬，高(gao)(gao)(gao)度有(you)1.5米高(gao)(gao)(gao)，估(gu)計完(wan)整的(de)(de)脊(ji)(ji)椎(zhui)可達2.7米高(gao)(gao)(gao)。他于(yu)1878年把這個標本運送給科(ke)(ke)普，而科(ke)(ke)普以此作為新種易碎雙(shuang)(shuang)腔(qiang)龍(long)(long)的(de)(de)正模標本（編號AMNH 5777），并于(yu)同年8月公布。它的(de)(de)名字是(shi)由古希臘文的(de)(de)“fragillimus”而來，即“非常(chang)易碎”，意指神經弓的(de)(de)椎(zhui)板非常(chang)薄。從科(ke)(ke)普發(fa)(fa)(fa)(fa)掘(jue)時的(de)(de)紀錄(lu)得(de)知，這個標本從發(fa)(fa)(fa)(fa)現圓(yuan)頂龍(long)(long)的(de)(de)礦場南面的(de)(de)山(shan)上(shang)被(bei)發(fa)(fa)(fa)(fa)現。科(ke)(ke)普指該位(wei)置是(shi)屬(shu)于(yu)達科(ke)(ke)他組(zu)（Dakota Formation），年代為侏(zhu)羅(luo)紀晚(wan)期，而在(zai)同一地層的(de)(de)圓(yuan)頂龍(long)(long)則是(shi)屬(shu)于(yu)莫里遜組(zu)（Morrison Formation），年代可追(zhui)溯至晚(wan)侏(zhu)羅(luo)紀的(de)(de)提通(tong)階。一塊巨(ju)大(da)的(de)(de)股骨化石亦在(zai)附(fu)近被(bei)發(fa)(fa)(fa)(fa)現，被(bei)估(gu)計可能也是(shi)屬(shu)于(yu)易碎雙(shuang)(shuang)腔(qiang)龍(long)(long)。

化石的疑問

當討論最大的(de)(de)(de)(de)恐龍(long)時，一般(ban)(ban)都會忽略易(yi)碎(sui)(sui)雙腔龍(long)的(de)(de)(de)(de)巨大骨(gu)骼，這(zhe)是(shi)(shi)因由(you)于不(bu)(bu)同的(de)(de)(de)(de)報告(gao)都指(zhi)其脊椎(zhui)及股骨(gu)的(de)(de)(de)(de)下落不(bu)(bu)明，而(er)嘗試尋找的(de)(de)(de)(de)計劃都失敗。于2006年(nian)，肯(ken)尼思(si)·卡彭特(te)（Kenneth Carpenter）指(zhi)出易(yi)碎(sui)(sui)雙腔龍(long)標本失蹤的(de)(de)(de)(de)可(ke)(ke)能原因：由(you)于科(ke)普在其描述(shu)中指(zhi)該神經弓非(fei)常易(yi)碎(sui)(sui)，而(er)當時并沒有(you)使(shi)骨(gu)頭硬(ying)化(hua)及保(bao)存化(hua)石(shi)(shi)的(de)(de)(de)(de)相關技術；科(ke)普的(de)(de)(de)(de)對(dui)手，奧塞(sai)內爾·查(cha)利(li)斯·馬什（Othniel Charles Marsh）在1880年(nian)代首(shou)次(ci)采用此一技術。而(er)保(bao)有(you)易(yi)碎(sui)(sui)雙腔龍(long)化(hua)石(shi)(shi)的(de)(de)(de)(de)石(shi)(shi)礦是(shi)(shi)嚴重侵蝕的(de)(de)(de)(de)泥巖，使(shi)得該化(hua)石(shi)(shi)容(rong)易(yi)被粉(fen)碎(sui)(sui)及形成小型、不(bu)(bu)規則的(de)(de)(de)(de)碎(sui)(sui)片。所以，它可(ke)(ke)能在科(ke)普描繪完后就(jiu)被粉(fen)碎(sui)(sui)了，所以科(ke)普的(de)(de)(de)(de)插(cha)圖(tu)(tu)就(jiu)只有(you)一個視圖(tu)(tu)，而(er)不(bu)(bu)是(shi)(shi)一般(ban)(ban)的(de)(de)(de)(de)多(duo)個視圖(tu)(tu)。但(dan)是(shi)(shi)今(jin)天來看易(yi)碎(sui)(sui)雙腔龍(long)確實存在，還(huan)是(shi)(shi)有(you)史以來最大的(de)(de)(de)(de)動物。

尋找化石

1994年，有(you)(you)科(ke)學家(jia)嘗試去(qu)找出易碎(sui)雙腔龍的(de)(de)(de)原(yuan)有(you)(you)石(shi)(shi)礦(kuang)，當中使(shi)用了雷達來探測地下藏有(you)(you)的(de)(de)(de)骨(gu)頭影像。這個嘗試最后(hou)失敗(bai)，是(shi)由于化石(shi)(shi)化的(de)(de)(de)泥巖與周邊的(de)(de)(de)巖石(shi)(shi)同(tong)一(yi)密度(du)，以致(zhi)不能分辨出兩者(zhe)。另一(yi)個地形研究指出藏有(you)(you)化石(shi)(shi)的(de)(de)(de)地層(ceng)經(jing)已受嚴重侵(qin)(qin)蝕，可(ke)能在(zai)(zai)發掘易碎(sui)雙腔龍的(de)(de)(de)脊(ji)椎及(ji)(ji)股骨(gu)后(hou)，該地的(de)(de)(de)大(da)部分的(de)(de)(de)骨(gu)骼(ge)已經(jing)侵(qin)(qin)蝕、消失。由于易碎(sui)雙腔龍化石(shi)(shi)的(de)(de)(de)特殊尺寸及(ji)(ji)神秘失蹤，科(ke)普(pu)的(de)(de)(de)原(yuan)始描(miao)述就引來了懷疑(yi)，有(you)(you)些人更指科(ke)普(pu)可(ke)能是(shi)在(zai)(zai)量度(du)上出現(xian)(xian)了排版印刷之誤。但(dan)是(shi)卡彭特指出科(ke)普(pu)的(de)(de)(de)文章充滿根據(ju)，也顯示他(ta)是(shi)一(yi)位出色的(de)(de)(de)古生物學家(jia)。而發現(xian)(xian)化石(shi)(shi)的(de)(de)(de)時(shi)間(jian)正好(hao)是(shi)化石(shi)(shi)戰爭，當時(shi)科(ke)普(pu)的(de)(de)(de)競敵奧塞內爾·查(cha)利斯·馬(ma)什（O.C. Marsh）卻從沒有(you)(you)對(dui)易碎(sui)雙腔龍提出懷疑(yi)。而馬(ma)什亦曾雇用偵(zhen)探監視科(ke)普(pu)的(de)(de)(de)發現(xian)(xian)，可(ke)能對(dui)易碎(sui)雙腔龍骨(gu)頭的(de)(de)(de)巨大(da)有(you)(you)了確定。而奧斯本、C.C. Mook、 John S. McIntosh等不同(tong)的(de)(de)(de)學者(zhe)亦都接受科(ke)普(pu)的(de)(de)(de)資料。所以易碎(sui)雙腔龍確實存在(zai)(zai)。

分類

科普將他的發現于1878年兩度公布于(yu)(yu)《美國博物學家》（The American Naturalist）期(qi)刊(kan)，并分(fen)(fen)類(lei)在(zai)新的(de)(de)雙(shuang)(shuang)(shuang)腔龍(long)(long)(long)屬(shu)(shu)(shu)下(xia)。他把(ba)這個屬(shu)(shu)(shu)編(bian)入(ru)梁龍(long)(long)(long)科(ke)內，雖然只(zhi)有(you)部(bu)分(fen)(fen)的(de)(de)化石碎片(pian)，有(you)些學者則將它分(fen)(fen)類(lei)在(zai)梁龍(long)(long)(long)超科(ke)下(xia)，或是(shi)(shi)(shi)梁龍(long)(long)(long)科(ke)的(de)(de)“分(fen)(fen)類(lei)未定屬(shu)(shu)(shu)”。雙(shuang)(shuang)(shuang)腔龍(long)(long)(long)屬(shu)(shu)(shu)中首先被命名(ming)的(de)(de)種是(shi)(shi)(shi)高雙(shuang)(shuang)(shuang)腔龍(long)(long)(long)（正(zheng)模(mo)標本(ben)(ben)AMHD 5764），是(shi)(shi)(shi)由科(ke)普于(yu)(yu)1877年發現。雖然只(zhi)有(you)部(bu)分(fen)(fen)的(de)(de)骨骼，但有(you)足(zu)夠特征(zheng)可(ke)以(yi)(yi)確定此屬(shu)(shu)(shu)的(de)(de)一些特征(zheng)。高雙(shuang)(shuang)(shuang)腔龍(long)(long)(long)的(de)(de)化石較(jiao)為(wei)完好，但就比易(yi)碎雙(shuang)(shuang)(shuang)腔龍(long)(long)(long)為(wei)小。在(zai)1921年，奧斯本(ben)(ben)與C.C. Mook指(zhi)出(chu)易(yi)碎雙(shuang)(shuang)(shuang)腔龍(long)(long)(long)其(qi)實只(zhi)是(shi)(shi)(shi)非常大的(de)(de)高雙(shuang)(shuang)(shuang)腔龍(long)(long)(long)，是(shi)(shi)(shi)高雙(shuang)(shuang)(shuang)腔龍(long)(long)(long)的(de)(de)異(yi)名(ming)；在(zai)1998年，John S. McIntosh也(ye)同意(yi)這個看法。但是(shi)(shi)(shi)卡彭(peng)特指(zhi)出(chu)，它們(men)在(zai)脊椎的(de)(de)構造上有(you)所差異(yi)，足(zu)以(yi)(yi)顯示它們(men)是(shi)(shi)(shi)不同的(de)(de)種，或甚至不同的(de)(de)屬(shu)(shu)(shu)。

體型

若要估計易碎雙腔龍的大小，就須假設它與梁龍科的相對比例(li)相(xiang)似，以較多(duo)(duo)了解的(de)(de)(de)(de)梁龍(long)(long)(long)(long)(long)(long)科的(de)(de)(de)(de)骨頭作(zuo)縮放比例(li)。在(zai)科普原先(xian)的(de)(de)(de)(de)紀錄，他以此(ci)來(lai)估(gu)(gu)(gu)計(ji)(ji)(ji)易(yi)(yi)(yi)碎(sui)(sui)雙(shuang)腔(qiang)龍(long)(long)(long)(long)(long)(long)的(de)(de)(de)(de)股(gu)(gu)骨大(da)小(xiao)(xiao)。科普發現(xian)(xian)在(zai)其(qi)他的(de)(de)(de)(de)蜥腳(jiao)下目恐龍(long)(long)(long)(long)(long)(long)，尤其(qi)是高(gao)雙(shuang)腔(qiang)龍(long)(long)(long)(long)(long)(long)及至高(gao)圓頂(ding)龍(long)(long)(long)(long)(long)(long)，它們的(de)(de)(de)(de)股(gu)(gu)骨都是背部最(zui)高(gao)脊椎(zhui)的(de)(de)(de)(de)兩倍(bei)高(gao)度，因而估(gu)(gu)(gu)計(ji)(ji)(ji)易(yi)(yi)(yi)碎(sui)(sui)雙(shuang)腔(qiang)龍(long)(long)(long)(long)(long)(long)的(de)(de)(de)(de)股(gu)(gu)骨為(wei)(wei)3.7米(mi)高(gao)，前腿(tui)(tui)5.75米(mi)長(chang)，后腿(tui)(tui)7.5米(mi)長(chang)，臀部高(gao)度為(wei)(wei)9.7米(mi)。但這些(xie)都是比較保守的(de)(de)(de)(de)估(gu)(gu)(gu)計(ji)(ji)(ji)值(zhi)，可能和實際的(de)(de)(de)(de)體(ti)(ti)格大(da)小(xiao)(xiao)有出(chu)入(ru)，或(huo)許(xu)比這小(xiao)(xiao)一些(xie)，或(huo)者(zhe)還(huan)要大(da)很多(duo)(duo)。于(yu)1994年(nian)，葛瑞格利(li)(li)·保羅（Gregory S. Paul）利(li)(li)用相(xiang)關的(de)(de)(de)(de)梁龍(long)(long)(long)(long)(long)(long)作(zuo)為(wei)(wei)參考(kao)，估(gu)(gu)(gu)計(ji)(ji)(ji)易(yi)(yi)(yi)碎(sui)(sui)雙(shuang)腔(qiang)龍(long)(long)(long)(long)(long)(long)的(de)(de)(de)(de)股(gu)(gu)骨大(da)小(xiao)(xiao)為(wei)(wei)3.1到4米(mi)長(chang)。于(yu)2006年(nian)，卡(ka)彭(peng)特(te)就同(tong)(tong)樣(yang)利(li)(li)用梁龍(long)(long)(long)(long)(long)(long)重新評估(gu)(gu)(gu)易(yi)(yi)(yi)碎(sui)(sui)雙(shuang)腔(qiang)龍(long)(long)(long)(long)(long)(long)的(de)(de)(de)(de)股(gu)(gu)骨為(wei)(wei)4.3到4.6米(mi)。卡(ka)彭(peng)特(te)嘗試就整頭易(yi)(yi)(yi)碎(sui)(sui)雙(shuang)腔(qiang)龍(long)(long)(long)(long)(long)(long)的(de)(de)(de)(de)體(ti)(ti)型(xing)作(zuo)出(chu)評估(gu)(gu)(gu)，但發現(xian)(xian)梁龍(long)(long)(long)(long)(long)(long)不同(tong)(tong)種的(de)(de)(de)(de)體(ti)(ti)型(xing)差(cha)異，會影響其(qi)估(gu)(gu)(gu)計(ji)(ji)(ji)結果。假設易(yi)(yi)(yi)碎(sui)(sui)雙(shuang)腔(qiang)龍(long)(long)(long)(long)(long)(long)與梁龍(long)(long)(long)(long)(long)(long)有著同(tong)(tong)一的(de)(de)(de)(de)比例(li)，它的(de)(de)(de)(de)體(ti)(ti)型(xing)就是58米(mi)，與保羅在(zai)1994年(nian)的(de)(de)(de)(de)估(gu)(gu)(gu)計(ji)(ji)(ji)范圍（40到60米(mi)）吻(wen)合(he)。卡(ka)彭(peng)特(te)也指出(chu)易(yi)(yi)(yi)碎(sui)(sui)雙(shuang)腔(qiang)龍(long)(long)(long)(long)(long)(long)的(de)(de)(de)(de)最(zui)小(xiao)(xiao)估(gu)(gu)(gu)計(ji)(ji)(ji)值(zhi)，亦(yi)比其(qi)他蜥腳(jiao)下目更為(wei)(wei)巨大(da)，如超龍(long)(long)(long)(long)(long)(long)（32.5米(mi)）、腕龍(long)(long)(long)(long)(long)(long)科的(de)(de)(de)(de)波塞東龍(long)(long)(long)(long)(long)(long)（34米(mi)）及泰坦巨龍(long)(long)(long)(long)(long)(long)類的(de)(de)(de)(de)阿根廷龍(long)(long)(long)(long)(long)(long)（35米(mi)），因此(ci)易(yi)(yi)(yi)碎(sui)(sui)雙(shuang)腔(qiang)龍(long)(long)(long)(long)(long)(long)從(cong)體(ti)(ti)形上(shang)來(lai)講才(cai)是最(zui)大(da)的(de)(de)(de)(de)恐龍(long)(long)(long)(long)(long)(long)，也是史上(shang)最(zui)大(da)的(de)(de)(de)(de)動物(wu)。

假設易(yi)(yi)(yi)碎(sui)(sui)雙(shuang)腔(qiang)龍(long)(long)(long)(long)(long)(long)相(xiang)當瘦(shou)，但其體(ti)型(xing)大(da)(da)(da)小(xiao)卻使(shi)它依舊的(de)(de)(de)巨大(da)(da)(da)。與長度相(xiang)比(bi)，體(ti)重(zhong)(zhong)更(geng)難去估計(ji)，因為(wei)(wei)要使(shi)用(yong)(yong)更(geng)為(wei)(wei)復雜的(de)(de)(de)方程式，比(bi)例上的(de)(de)(de)小(xiao)型(xing)差異就(jiu)會產生(sheng)很大(da)(da)(da)的(de)(de)(de)誤差。以(yi)(yi)卡(ka)內基梁龍(long)(long)(long)(long)(long)(long)（Diplodocus carnegii）的(de)(de)(de)估計(ji)質量為(wei)(wei)120公噸(dun)，易(yi)(yi)(yi)碎(sui)(sui)雙(shuang)腔(qiang)龍(long)(long)(long)(long)(long)(long)的(de)(de)(de)體(ti)重(zhong)(zhong)就(jiu)可以(yi)(yi)是180---220噸(dun)。易(yi)(yi)(yi)碎(sui)(sui)雙(shuang)腔(qiang)龍(long)(long)(long)(long)(long)(long)體(ti)重(zhong)(zhong)大(da)(da)(da)于阿根(gen)廷龍(long)(long)(long)(long)(long)(long)的(de)(de)(de)100噸(dun)。近期,科學家(jia)們重(zhong)(zhong)新研究估計(ji),發現易(yi)(yi)(yi)碎(sui)(sui)雙(shuang)腔(qiang)龍(long)(long)(long)(long)(long)(long)和(he)近親梁龍(long)(long)(long)(long)(long)(long)關系較(jiao)遠,而和(he)超龍(long)(long)(long)(long)(long)(long)迷惑(huo)龍(long)(long)(long)(long)(long)(long)更(geng)近,認(ren)為(wei)(wei)之前(qian)(qian)利用(yong)(yong)梁龍(long)(long)(long)(long)(long)(long)估計(ji)易(yi)(yi)(yi)碎(sui)(sui)雙(shuang)腔(qiang)龍(long)(long)(long)(long)(long)(long)的(de)(de)(de)體(ti)型(xing)得出(chu)來的(de)(de)(de)結(jie)論是不準確得。而利用(yong)(yong)超龍(long)(long)(long)(long)(long)(long)和(he)迷惑(huo)龍(long)(long)(long)(long)(long)(long)估算后,得出(chu)了新的(de)(de)(de)數據。體(ti)長可達到(dao)60---80米(mi)甚至(zhi)以(yi)(yi)上，體(ti)重(zhong)(zhong)190噸(dun)以(yi)(yi)上,這(zhe)個(ge)(ge)(ge)顯(xian)然和(he)這(zhe)個(ge)(ge)(ge)巨型(xing)動物(wu)的(de)(de)(de)真實體(ti)重(zhong)(zhong)更(geng)加(jia)符(fu)合。目前(qian)(qian)科學家(jia)普遍(bian)認(ren)為(wei)(wei)，易(yi)(yi)(yi)碎(sui)(sui)最大(da)(da)(da)個(ge)(ge)(ge)體(ti)可達60---80米(mi)長、臀高(gao)(gao)10米(mi)、頭高(gao)(gao)14-15米(mi)之間、體(ti)重(zhong)(zhong)最重(zhong)(zhong)220噸(dun)。