懼(ju)龍(long)是(shi)非常著名(ming)的(de)北美洲大型(xing)暴龍(long)類,是(shi)其所處(chu)時(shi)代體型(xing)最大的(de)捕食(shi)者。懼(ju)龍(long)屬下目前有兩(liang)個種(zhong),即模式種(zhong)強健(jian)懼(ju)龍(long)和(he)歸入種(zhong)霍(huo)氏懼(ju)龍(long)。懼(ju)龍(long)的(de)體長約(yue)為(wei)9米(mi),與蛇發女怪龍(long)和(he)阿爾伯塔龍(long)相似,但是(shi)卻更為(wei)健(jian)壯。一些研究(jiu)認為(wei)懼(ju)龍(long)的(de)體重可以達到3.5噸以上。
與霸王龍,特暴龍,蛇發(fa)女怪(guai)龍和阿爾伯塔龍一(yi)樣,懼龍也有比較豐富的標本收藏,因(yin)此(ci)成為(wei)被研究(jiu)的最細致的大型(xing)暴龍類之(zhi)一(yi)。
懼(ju)龍(long)的屬(shu)名(ming)意(yi)為可(ke)怕(pa)的蜥蜴,這(zhe)一(yi)屬(shu)名(ming)經常也(ye)被譯作(zuo)(zuo)可(ke)畏龍(long)。模式種種名(ming)的含義(yi)為強壯的。相比于同體(ti)長(chang)的阿爾伯塔龍(long)亞科(ke),懼(ju)龍(long)確實更(geng)為健(jian)壯,頭骨也(ye)顯得(de)更(geng)加厚實。歸入種種名(ming)是為了紀(ji)念古生(sheng)(sheng)物學(xue)(xue)(xue)家杰克.霍(huo)(huo)(huo)(huo)納(na)(na)(na)在(zai)雙麥迪遜組的野外工作(zuo)(zuo),以(yi)及霍(huo)(huo)(huo)(huo)納(na)(na)(na)本人對恐龍(long)古生(sheng)(sheng)物學(xue)(xue)(xue)做(zuo)出(chu)的杰出(chu)貢獻。這(zhe)里順(shun)帶(dai)說一(yi)下,杰克.霍(huo)(huo)(huo)(huo)納(na)(na)(na)曾是《侏(zhu)(zhu)羅(luo)(luo)紀(ji)公園》的科(ke)學(xue)(xue)(xue)顧問,而(er)在(zai)重啟的《侏(zhu)(zhu)羅(luo)(luo)紀(ji)世界》中,劇(ju)組也(ye)在(zai)影(ying)片中致敬了他,讓(rang)他客串了一(yi)下(歐(ou)文(wen)第一(yi)次出(chu)場(chang)訓練伶盜龍(long)的時候)。霍(huo)(huo)(huo)(huo)納(na)(na)(na)在(zai)TED上還有(you)一(yi)個著名(ming)的演講(jiang)叫《恐龍(long)也(ye)變形》,主要講(jiang)述的是過去古生(sheng)(sheng)物學(xue)(xue)(xue)研究中把同一(yi)物種幼(you)年個體(ti)當(dang)成(cheng)新種重新命名(ming)的問題,以(yi)及他在(zai)解決這(zhe)方(fang)面問題上所做(zuo)的努力。
懼龍兩(liang)側的(de)(de)(de)(de)(de)(de)前(qian)(qian)頜(he)骨(gu)(gu)(gu)(gu)(gu)(gu)鼻(bi)(bi)(bi)骨(gu)(gu)(gu)(gu)(gu)(gu)突(tu)緊緊的(de)(de)(de)(de)(de)(de)貼(tie)在一(yi)(yi)起(qi),將兩(liang)側鼻(bi)(bi)(bi)骨(gu)(gu)(gu)(gu)(gu)(gu)的(de)(de)(de)(de)(de)(de)前(qian)(qian)緣(yuan)分(fen)(fen)開(kai)。在蛇(she)發女怪(guai)(guai)龍中,鼻(bi)(bi)(bi)骨(gu)(gu)(gu)(gu)(gu)(gu)具有一(yi)(yi)內側突(tu),將前(qian)(qian)頜(he)骨(gu)(gu)(gu)(gu)(gu)(gu)鼻(bi)(bi)(bi)骨(gu)(gu)(gu)(gu)(gu)(gu)突(tu)的(de)(de)(de)(de)(de)(de)后端分(fen)(fen)開(kai)。上頜(he)骨(gu)(gu)(gu)(gu)(gu)(gu)的(de)(de)(de)(de)(de)(de)外(wai)側緣(yuan)具有兩(liang)排略呈平行排列的(de)(de)(de)(de)(de)(de)滋養孔。懼龍的(de)(de)(de)(de)(de)(de)淚骨(gu)(gu)(gu)(gu)(gu)(gu)與(yu)上頜(he)骨(gu)(gu)(gu)(gu)(gu)(gu)的(de)(de)(de)(de)(de)(de)關節與(yu)阿爾(er)伯塔龍類似(si),但是在懼龍的(de)(de)(de)(de)(de)(de)成(cheng)年個體中,兩(liang)者的(de)(de)(de)(de)(de)(de)關節不(bu)(bu)會被鼻(bi)(bi)(bi)骨(gu)(gu)(gu)(gu)(gu)(gu)分(fen)(fen)開(kai)。懼龍的(de)(de)(de)(de)(de)(de)鼻(bi)(bi)(bi)骨(gu)(gu)(gu)(gu)(gu)(gu)在鼻(bi)(bi)(bi)骨(gu)(gu)(gu)(gu)(gu)(gu)-淚骨(gu)(gu)(gu)(gu)(gu)(gu)關節點之后急劇的(de)(de)(de)(de)(de)(de)收縮(suo),不(bu)(bu)同于蛇(she)發女怪(guai)(guai)龍和阿爾(er)伯塔龍,它(ta)們的(de)(de)(de)(de)(de)(de)鼻(bi)(bi)(bi)骨(gu)(gu)(gu)(gu)(gu)(gu)在這一(yi)(yi)關節點以后內外(wai)側擴展(zhan)。鼻(bi)(bi)(bi)骨(gu)(gu)(gu)(gu)(gu)(gu)的(de)(de)(de)(de)(de)(de)腹外(wai)側緣(yuan)具有一(yi)(yi)條(tiao)溝與(yu)上頜(he)骨(gu)(gu)(gu)(gu)(gu)(gu),淚骨(gu)(gu)(gu)(gu)(gu)(gu)和前(qian)(qian)額骨(gu)(gu)(gu)(gu)(gu)(gu)相關節,在成(cheng)年的(de)(de)(de)(de)(de)(de)懼龍中,這條(tiao)溝被一(yi)(yi)道脊分(fen)(fen)開(kai),而在蛇(she)發女怪(guai)(guai)龍和阿爾(er)伯塔龍中是連續的(de)(de)(de)(de)(de)(de)。在蛇(she)發女怪(guai)(guai)龍的(de)(de)(de)(de)(de)(de)鼻(bi)(bi)(bi)骨(gu)(gu)(gu)(gu)(gu)(gu)上,這條(tiao)溝的(de)(de)(de)(de)(de)(de)后端具有一(yi)(yi)指手指狀突(tu)起(qi)與(yu)淚骨(gu)(gu)(gu)(gu)(gu)(gu)的(de)(de)(de)(de)(de)(de)前(qian)(qian)邊緣(yuan)關節,而這一(yi)(yi)突(tu)起(qi)在懼龍中不(bu)(bu)存在。
蛇(she)(she)發女(nv)怪(guai)龍(long)(long)和(he)阿爾伯塔(ta)龍(long)(long)的(de)淚骨(gu)的(de)背外側面(mian)具(ju)有(you)一(yi)(yi)發達的(de)骨(gu)質(zhi)角(jiao),而(er)懼龍(long)(long)的(de)成年個體的(de)淚骨(gu)具(ju)有(you)一(yi)(yi)延(yan)長的(de)脊(ji)。淚骨(gu)的(de)后背側角(jiao)的(de)氣孔(kong)在蛇(she)(she)發女(nv)怪(guai)龍(long)(long)和(he)阿爾伯塔(ta)龍(long)(long)中(zhong)(zhong)比較(jiao)發達,而(er)在懼龍(long)(long)中(zhong)(zhong)比較(jiao)小且呈(cheng)三角(jiao)形。在蛇(she)(she)發女(nv)怪(guai)龍(long)(long)和(he)阿爾伯塔(ta)龍(long)(long)中(zhong)(zhong),淚骨(gu)的(de)氣孔(kong)之間(jian)由較(jiao)短的(de)骨(gu)質(zhi)分隔(ge)隔(ge)開(kai),而(er)在懼龍(long)(long)中(zhong)(zhong),這一(yi)(yi)骨(gu)質(zhi)分隔(ge)非常發達,甚至(zhi)比氣孔(kong)還(huan)要大(da)。與蛇(she)(she)發女(nv)怪(guai)龍(long)(long)相比,懼龍(long)(long)的(de)前額骨(gu)要更加狹長,其前端一(yi)(yi)直延(yan)伸至(zhi)額骨(gu)前邊緣的(de)前面(mian),而(er)蛇(she)(she)發女(nv)怪(guai)龍(long)(long)的(de)前額骨(gu)最多延(yan)伸至(zhi)與額骨(gu)前邊緣同一(yi)(yi)位置。
懼龍(long)(long)(long)(long)(long)(long)額(e)骨(gu)的后四分之一(yi)隆起參與(yu)到(dao)矢狀(zhuang)脊的形(xing)成中,因此它的矢狀(zhuang)脊比蛇(she)(she)發(fa)女(nv)(nv)怪龍(long)(long)(long)(long)(long)(long)和阿爾(er)(er)(er)(er)(er)伯塔龍(long)(long)(long)(long)(long)(long)的要更(geng)(geng)高聳(song)。懼龍(long)(long)(long)(long)(long)(long)的頂骨(gu)頸(jing)背脊較(jiao)阿爾(er)(er)(er)(er)(er)伯塔龍(long)(long)(long)(long)(long)(long)和蛇(she)(she)發(fa)女(nv)(nv)怪龍(long)(long)(long)(long)(long)(long)的低矮,但(dan)是(shi)更(geng)(geng)寬。懼龍(long)(long)(long)(long)(long)(long)眶(kuang)后骨(gu)上的骨(gu)質結節(jie)明顯比阿爾(er)(er)(er)(er)(er)伯塔龍(long)(long)(long)(long)(long)(long)和蛇(she)(she)發(fa)女(nv)(nv)怪龍(long)(long)(long)(long)(long)(long)的發(fa)達(da)。位(wei)于(yu)顴(quan)(quan)骨(gu)上,眶(kuang)前窩后腹側角(jiao)上的氣孔(kong)在蛇(she)(she)發(fa)女(nv)(nv)怪龍(long)(long)(long)(long)(long)(long)和阿爾(er)(er)(er)(er)(er)伯塔龍(long)(long)(long)(long)(long)(long)中較(jiao)為發(fa)達(da),而(er)在懼龍(long)(long)(long)(long)(long)(long)中比較(jiao)小。懼龍(long)(long)(long)(long)(long)(long)的顴(quan)(quan)骨(gu)具有前后向(xiang)變(bian)短但(dan)背腹向(xiang)加深(shen)的角(jiao)狀(zhuang)突,這一(yi)點(dian)與(yu)阿爾(er)(er)(er)(er)(er)伯塔龍(long)(long)(long)(long)(long)(long)和蛇(she)(she)發(fa)女(nv)(nv)怪龍(long)(long)(long)(long)(long)(long)不同。顴(quan)(quan)骨(gu)位(wei)于(yu)眼眶(kuang)下部(bu)分的背腹向(xiang)深(shen)度(du)較(jiao)阿爾(er)(er)(er)(er)(er)伯塔龍(long)(long)(long)(long)(long)(long)和蛇(she)(she)發(fa)女(nv)(nv)怪龍(long)(long)(long)(long)(long)(long)有所減小,但(dan)是(shi)內外(wai)側寬度(du)有明顯的加厚。方(fang)顴(quan)(quan)骨(gu)與(yu)鱗骨(gu)的關節(jie)面在前后向(xiang)延長,與(yu)阿爾(er)(er)(er)(er)(er)伯塔龍(long)(long)(long)(long)(long)(long)亞(ya)(ya)(ya)科的成員有明顯區別。基蝶(die)骨(gu)竇(dou)較(jiao)淺較(jiao)寬,與(yu)多數暴龍(long)(long)(long)(long)(long)(long)亞(ya)(ya)(ya)科相似,不同于(yu)阿爾(er)(er)(er)(er)(er)伯塔龍(long)(long)(long)(long)(long)(long)亞(ya)(ya)(ya)科。
霍氏懼(ju)龍與強(qiang)健(jian)懼(ju)龍的(de)(de)(de)(de)(de)區別包括以下特征組合:上(shang)(shang)頜骨(gu)(gu)的(de)(de)(de)(de)(de)第一個齒間板比(bi)較(jiao)小(xiao)。齒骨(gu)(gu)向(xiang)外(wai)側(ce)拱起。前(qian)頜竇終止于(yu)第3和第4齒槽(cao)之(zhi)間。內鼻孔的(de)(de)(de)(de)(de)前(qian)邊(bian)(bian)緣位于(yu)上(shang)(shang)頜骨(gu)(gu)第7個齒槽(cao)的(de)(de)(de)(de)(de)位置(zhi)。淚骨(gu)(gu)的(de)(de)(de)(de)(de)背面(mian)(mian)膨(peng)大(da),但是(shi)內側(ce)面(mian)(mian)沒有(you)膨(peng)大(da)。淚骨(gu)(gu)降支(zhi)內側(ce)的(de)(de)(de)(de)(de)氣(qi)孔不(bu)如強(qiang)健(jian)懼(ju)龍的(de)(de)(de)(de)(de)發達。淚骨(gu)(gu)構成眼(yan)眶邊(bian)(bian)緣的(de)(de)(de)(de)(de)上(shang)(shang)半部分(fen)具有(you)明(ming)顯的(de)(de)(de)(de)(de)凹陷。位于(yu)額骨(gu)(gu)上(shang)(shang)的(de)(de)(de)(de)(de)上(shang)(shang)顳窩(wo)前(qian)邊(bian)(bian)緣為曲線,強(qiang)健(jian)懼(ju)龍中是(shi)直(zhi)線。頂(ding)骨(gu)(gu)的(de)(de)(de)(de)(de)后(hou)外(wai)側(ce)突(tu)的(de)(de)(de)(de)(de)基部被頂(ding)骨(gu)(gu)的(de)(de)(de)(de)(de)鱗(lin)骨(gu)(gu)關(guan)節突(tu)覆蓋(gai)。鼓室脊延(yan)伸(shen)至(zhi)前(qian)耳骨(gu)(gu)上(shang)(shang)。方顴骨(gu)(gu)的(de)(de)(de)(de)(de)外(wai)側(ce)面(mian)(mian)具有(you)一明(ming)顯的(de)(de)(de)(de)(de)穿孔。
懼龍的(de)化(hua)石標本(ben)也非常多,有(you)一些(xie)甚(shen)至沒有(you)經過正式的(de)發表描述。以下先列(lie)出強健(jian)懼龍的(de)一些(xie)已發表的(de)標本(ben)。
強健(jian)懼龍(long)的(de)正(zheng)型標本在發(fa)現之初被當作是(shi)蛇發(fa)女怪龍(long)的(de)的(de)標本。在戴爾(er).羅素1970年(nian)的(de)文(wen)章系統(tong)描述和比較加拿(na)大地區(qu)的(de)暴龍(long)類時(shi)才被定(ding)為新屬種。
正型標(biao)本:NMC 8506保存了頭骨,肩帶(dai)骨骼,前肢(zhi),腰帶(dai)和股骨,大多數(shu)的頸椎,背椎和薦(jian)椎,還有前11節(jie)尾椎。
歸入標本:AMNH 5438保存了(le)薦椎,背椎和(he)尾(wei)椎,腰帶,右側股骨(gu),左側脛骨(gu)和(he)第二跖(zhi)骨(gu)。
歸(gui)入標(biao)本:NMC 350保存了左側后肢(zhi)。
歸(gui)入標本:AMNH 5346為一件上(shang)頜骨。
歸(gui)入(ru)標本:UA 11右側股骨(gu)和第四跖(zhi)骨(gu)。
歸入標本:NMC 11594保存了不完整的,風化較嚴重的頭(tou)骨(gu)。
歸入標(biao)本:BMNH R4863保存了前頜(he)骨,上頜(he)骨和齒骨。
歸入標本:RTMP 2001.36.1一件幾乎完(wan)整的(de)骨架。
歸(gui)入(ru)標本:FMNH PR308是(shi)一件保(bao)存質量(liang)很好的標本,保(bao)存了頭骨和大多數頭后骨骼。起初被認為時阿爾(er)伯塔龍。后在托(tuo)馬斯.卡爾(er)1999年(nian)的研究(jiu)中(zhong)歸(gui)入(ru)到懼龍模(mo)式種。
歸(gui)入標本:AMNH 5434曾經被(bei)歸(gui)入到(dao)蛇發女(nv)怪龍模式種,保存了幾乎完整(zheng)的頭骨。頭后骨骼缺乏尾椎和(he)后肢,其它部(bu)位(wei)幾乎完整(zheng)。在托馬斯.卡爾1999年的工作中(zhong)歸(gui)入到(dao)懼龍模式種。
歸入(ru)標本:TMP 94.218.1為一個幼年個體(ti)。托馬(ma)斯.卡爾1999年的工作(zuo)中列出。
歸(gui)入標本(ben):NMC 841為一成年(nian)個體。托馬斯.卡(ka)爾1999年(nian)的工(gong)作中列(lie)出(chu)。
歸入(ru)標本:TMP 82.13.1為一個成(cheng)年個體。托馬斯.卡爾1999年的工作中列出。
歸入標本:TMP 83.38.1為一個(ge)成年(nian)(nian)個(ge)體。托馬斯(si).卡爾1999年(nian)(nian)的工作中列(lie)出。
歸入標本:TMP 85.62.1為一個成年個體。托馬斯.卡爾1999年的工作中(zhong)列出。
歸入(ru)標(biao)本:TMP 1994.143.0001屬于(yu)一(yi)只約(yue)5米長(chang)的年輕懼(ju)龍。頭(tou)骨(gu)幾乎完(wan)整,但頭(tou)后骨(gu)骼風(feng)化嚴(yan)重(zhong)。
下面列出霍氏懼(ju)龍的主要(yao)標本(ben):
正型標本:MOR 590保存(cun)了(le)完整的頭骨,部分保存(cun)的肩帶和前肢以及完整的后(hou)肢。
歸入(ru)標本:MOR 1130保存了一(yi)個(ge)不完整(zheng)的頭(tou)骨(gu),部分(fen)保存的中軸骨(gu)格序列,部分(fen)保存的腰(yao)帶骨(gu)骼(ge)和后肢。
歸入(ru)標(biao)本:MOR 553S/7.19.0.97一塊(kuai)齒骨,屬于一個小(xiao)幼體。
歸入(ru)標(biao)本:AMNH FARB 5477包括一塊(kuai)上(shang)頜骨(gu),部分保(bao)存的眶后(hou)骨(gu)和頂骨(gu)。
歸入(ru)標本:MOR 3068部分保(bao)存的(de)下頜(he)。
歸入標本:MOR 553D.9.19.91左側(ce)的外翼(yi)骨(gu)。
歸入標本(ben):MOR 553E.7.6.91.196,右側的外翼骨。
除此之(zhi)外(wai),還(huan)有(you)(you)一些(xie)被鑒(jian)定屬于(yu)懼(ju)龍屬,但是(shi)沒有(you)(you)明確(que)定種(zhong)的標本。它們有(you)(you)可(ke)能屬于(yu)已知(zhi)的兩種(zhong)懼(ju)龍,也(ye)有(you)(you)可(ke)能是(shi)第三種(zhong)。
目(mu)前(qian)主要的暴龍(long)(long)類或虛骨龍(long)(long)類系統發育分析都支持(chi)懼龍(long)(long)屬于暴龍(long)(long)亞(ya)科(ke),且與霸王龍(long)(long)和特暴龍(long)(long)(有時會包括諸(zhu)城暴龍(long)(long))具有非常(chang)近的親(qin)緣關系。而排除(chu)掉亞(ya)洲的暴龍(long)(long)類以后,懼龍(long)(long)是北美(mei)大陸上(shang)與霸王龍(long)(long)親(qin)緣關系最(zui)近的成員(yuan)。
懼龍的頭骨長度可以超(chao)過1米。戴爾.羅(luo)素對于懼龍的體(ti)型估計(ji)是(shi)體(ti)長8-9米。而體(ti)重(zhong)估計(ji)一般在2.5噸左右,但是(shi)具有較大的波動范圍(1.8至3.8噸)。2014年(nian)的一項(xiang)研究估計(ji)值為(wei)3.6噸。
2017年的(de)(de)(de)(de)(de)一項研(yan)究(jiu)參考現生的(de)(de)(de)(de)(de)主(zhu)龍(long)(long)類(lei)(lei)復原了懼(ju)龍(long)(long)的(de)(de)(de)(de)(de)面(mian)(mian)(mian)部(bu)(bu)軟組織(zhi)。研(yan)究(jiu)人員認為懼(ju)龍(long)(long)的(de)(de)(de)(de)(de)面(mian)(mian)(mian)部(bu)(bu)具(ju)有種(zhong)類(lei)(lei)豐富(fu)的(de)(de)(de)(de)(de)表(biao)皮組織(zhi),除(chu)了鱗片以(yi)外,在它的(de)(de)(de)(de)(de)前(qian)頜(he)骨(gu),鼻骨(gu)和淚(lei)骨(gu)還有顴骨(gu),以(yi)及(ji)齒骨(gu)的(de)(de)(de)(de)(de)吻(wen)端應(ying)該(gai)會覆(fu)(fu)蓋(gai)一些骨(gu)質的(de)(de)(de)(de)(de)小(xiao)突起,而眶后(hou)骨(gu)角的(de)(de)(de)(de)(de)表(biao)面(mian)(mian)(mian)應(ying)該(gai)會覆(fu)(fu)蓋(gai)有非(fei)常厚的(de)(de)(de)(de)(de)角質層(ceng)。除(chu)此之外,懼(ju)龍(long)(long)的(de)(de)(de)(de)(de)吻(wen)端還具(ju)有豐富(fu)的(de)(de)(de)(de)(de)神(shen)經陷窩。懼(ju)龍(long)(long)的(de)(de)(de)(de)(de)吻(wen)端可(ke)能與(yu)現生鱷(e)魚的(de)(de)(de)(de)(de)吻(wen)端具(ju)有相似(si)的(de)(de)(de)(de)(de)功能,包括捕獵,感受溫度和不(bu)同(tong)物體的(de)(de)(de)(de)(de)材質,以(yi)及(ji)同(tong)類(lei)(lei)之間的(de)(de)(de)(de)(de)社會性行為。吻(wen)部(bu)(bu)表(biao)面(mian)(mian)(mian)覆(fu)(fu)蓋(gai)的(de)(de)(de)(de)(de)骨(gu)質小(xiao)突起可(ke)能能夠起到(dao)對感受系(xi)統保護的(de)(de)(de)(de)(de)作用(yong)。
關于(yu)懼(ju)(ju)龍(long)(long)(long)群(qun)(qun)(qun)居性的(de)(de)(de)(de)證據(ju)在(zai)雙(shuang)麥迪遜組被(bei)(bei)找到。在(zai)一個(ge)產出(chu)(chu)懼(ju)(ju)龍(long)(long)(long)化(hua)石(shi)的(de)(de)(de)(de)骨(gu)床中(zhong)(zhong),至(zhi)少有屬于(yu)三個(ge)不同(tong)(tong)個(ge)體的(de)(de)(de)(de)懼(ju)(ju)龍(long)(long)(long)骨(gu)骼(ge)被(bei)(bei)發(fa)現(xian)。除此之(zhi)外,這(zhe)(zhe)里還發(fa)現(xian)了5具鴨嘴龍(long)(long)(long)類(lei)的(de)(de)(de)(de)化(hua)石(shi)。這(zhe)(zhe)些懼(ju)(ju)龍(long)(long)(long)骨(gu)骼(ge)中(zhong)(zhong),至(zhi)少有一只(zhi)大(da)型的(de)(de)(de)(de)成(cheng)年個(ge)體,一只(zhi)中(zhong)(zhong)等大(da)小的(de)(de)(de)(de)個(ge)體,還有一只(zhi)小幼體。依據(ju)對于(yu)化(hua)石(shi)點(dian)的(de)(de)(de)(de)埋(mai)藏學(xue)分析,這(zhe)(zhe)些尸(shi)體不像是被(bei)(bei)從別的(de)(de)(de)(de)地方沖(chong)下來的(de)(de)(de)(de),而像是在(zai)較短(duan)的(de)(de)(de)(de)時間內被(bei)(bei)同(tong)(tong)時埋(mai)藏的(de)(de)(de)(de)。5具鴨嘴龍(long)(long)(long)的(de)(de)(de)(de)骨(gu)骼(ge)上都有暴龍(long)(long)(long)類(lei)的(de)(de)(de)(de)齒痕,顯示這(zhe)(zhe)群(qun)(qun)(qun)懼(ju)(ju)龍(long)(long)(long)在(zai)死前可能進食過這(zhe)(zhe)些尸(shi)體。菲(fei)利普.柯瑞認為這(zhe)(zhe)批化(hua)石(shi)是懼(ju)(ju)龍(long)(long)(long)群(qun)(qun)(qun)居性行為的(de)(de)(de)(de)證據(ju),并且推測它們會成(cheng)群(qun)(qun)(qun)出(chu)(chu)動(dong)協同(tong)(tong)捕獵。其他古生物學(xue)家則對此持懷疑態(tai)度。
同(tong)(tong)類(lei)相殘(can)(can)在現(xian)生(sheng)的(de)(de)(de)(de)(de)大(da)型(xing)(xing)(xing)(xing)食肉動(dong)(dong)物(wu)中是(shi)一(yi)種(zhong)常(chang)見(jian)的(de)(de)(de)(de)(de)現(xian)象。化(hua)石(shi)證(zheng)據(ju)顯示(shi)這種(zhong)現(xian)象在獸(shou)腳類(lei)恐龍(long)(long)(long)(long)(long)(long)(long)中也比較常(chang)見(jian)。一(yi)件(jian)年(nian)輕的(de)(de)(de)(de)(de)懼龍(long)(long)(long)(long)(long)(long)(long)標本(ben)的(de)(de)(de)(de)(de)面部留有(you)(you)暴(bao)龍(long)(long)(long)(long)(long)(long)(long)類(lei)的(de)(de)(de)(de)(de)咬(yao)痕。咬(yao)痕有(you)(you)愈合的(de)(de)(de)(de)(de)痕跡(ji),顯示(shi)這只動(dong)(dong)物(wu)在襲擊(ji)中活(huo)了(le)下來。另外一(yi)件(jian)成年(nian)的(de)(de)(de)(de)(de)懼龍(long)(long)(long)(long)(long)(long)(long)標本(ben)也有(you)(you)大(da)型(xing)(xing)(xing)(xing)暴(bao)龍(long)(long)(long)(long)(long)(long)(long)類(lei)的(de)(de)(de)(de)(de)咬(yao)痕。這些證(zheng)據(ju)顯示(shi),大(da)型(xing)(xing)(xing)(xing)暴(bao)龍(long)(long)(long)(long)(long)(long)(long)類(lei)的(de)(de)(de)(de)(de)同(tong)(tong)類(lei)相殘(can)(can)行為(wei)不止局限于(yu)傷害小體(ti)(ti)型(xing)(xing)(xing)(xing)的(de)(de)(de)(de)(de)個體(ti)(ti),同(tong)(tong)類(lei)間的(de)(de)(de)(de)(de)打斗在大(da)型(xing)(xing)(xing)(xing)個體(ti)(ti)間也存在。其(qi)它(ta)的(de)(de)(de)(de)(de)獸(shou)腳類(lei)如(ru)大(da)型(xing)(xing)(xing)(xing)暴(bao)龍(long)(long)(long)(long)(long)(long)(long)類(lei)蛇發女怪(guai)龍(long)(long)(long)(long)(long)(long)(long)和(he)霸王龍(long)(long)(long)(long)(long)(long)(long),還有(you)(you)大(da)型(xing)(xing)(xing)(xing)異特龍(long)(long)(long)(long)(long)(long)(long)類(lei)中華盜龍(long)(long)(long)(long)(long)(long)(long),以及小體(ti)(ti)型(xing)(xing)(xing)(xing)的(de)(de)(de)(de)(de)馳龍(long)(long)(long)(long)(long)(long)(long)類(lei)蜥(xi)鳥(niao)盜龍(long)(long)(long)(long)(long)(long)(long)的(de)(de)(de)(de)(de)頭(tou)骨上也會有(you)(you)被其(qi)它(ta)動(dong)(dong)物(wu)咬(yao)過的(de)(de)(de)(de)(de)痕跡(ji)。菲利普(pu).柯(ke)瑞(rui)認為(wei),獸(shou)腳類(lei)恐龍(long)(long)(long)(long)(long)(long)(long)之間的(de)(de)(de)(de)(de)攻擊(ji)性行為(wei)主(zhu)要是(shi)由于(yu)種(zhong)間競爭和(he)領(ling)域保(bao)護性行為(wei)導致的(de)(de)(de)(de)(de)。
大(da)(da)型(xing)(xing)暴(bao)龍類在個體發育過程(cheng)中的(de)(de)體重增加(jia)(jia)符(fu)合(he)“S”型(xing)(xing)曲線。懼(ju)龍的(de)(de)最(zui)大(da)(da)生(sheng)(sheng)(sheng)長(chang)(chang)速(su)度(du)(du)為每(mei)年180千(qian)克(ke),大(da)(da)于蛇發女怪龍和阿爾伯塔(ta)龍,而這(zhe)樣的(de)(de)結果(guo)還只(zhi)是使(shi)用(yong)了較低估(gu)計的(de)(de)成體體重(1.8噸)。使(shi)用(yong)更(geng)大(da)(da)的(de)(de)成體體重估(gu)計將會(hui)(hui)增加(jia)(jia)最(zui)大(da)(da)生(sheng)(sheng)(sheng)長(chang)(chang)速(su)率的(de)(de)估(gu)計值(zhi),但是并不會(hui)(hui)改變擬(ni)合(he)曲線的(de)(de)整體形狀(zhuang)。懼(ju)龍的(de)(de)最(zui)大(da)(da)生(sheng)(sheng)(sheng)長(chang)(chang)速(su)率遠低于霸王龍,且(qie)“S”型(xing)(xing)曲線更(geng)早達到漸進(jin)平緩(huan)。這(zhe)也表明,暴(bao)龍類在大(da)(da)型(xing)(xing)化的(de)(de)過程(cheng)中可能同時(shi)使(shi)用(yong)了增加(jia)(jia)最(zui)大(da)(da)生(sheng)(sheng)(sheng)長(chang)(chang)速(su)度(du)(du)和增加(jia)(jia)生(sheng)(sheng)(sheng)長(chang)(chang)時(shi)間的(de)(de)策略(lve)。
懼龍(long)(long)在(zai)個(ge)(ge)體(ti)(ti)(ti)發育的(de)(de)(de)(de)(de)過(guo)程中(zhong)(zhong)會經歷(li)一(yi)系列(lie)的(de)(de)(de)(de)(de)形態變(bian)化。最為明顯的(de)(de)(de)(de)(de)一(yi)點(dian)是牙(ya)齒(chi)數(shu)量(liang)的(de)(de)(de)(de)(de)變(bian)化。對于霍氏懼龍(long)(long)的(de)(de)(de)(de)(de)研(yan)究(jiu)發現(xian),最年輕(qing)(qing)的(de)(de)(de)(de)(de)個(ge)(ge)體(ti)(ti)(ti)的(de)(de)(de)(de)(de)上(shang)頜骨齒(chi)有15個(ge)(ge)(AMNH FARB 5477),而(er)亞(ya)成體(ti)(ti)(ti)的(de)(de)(de)(de)(de)增(zeng)加到了17個(ge)(ge)((MOR 590),之后成年個(ge)(ge)體(ti)(ti)(ti)的(de)(de)(de)(de)(de)數(shu)量(liang)又下(xia)降到15個(ge)(ge)(MOR 1130)。與上(shang)頜相比(bi),齒(chi)骨齒(chi)的(de)(de)(de)(de)(de)數(shu)量(liang)在(zai)個(ge)(ge)體(ti)(ti)(ti)發育中(zhong)(zhong)沒有變(bian)化。強(qiang)健(jian)懼龍(long)(long)在(zai)個(ge)(ge)體(ti)(ti)(ti)發育的(de)(de)(de)(de)(de)過(guo)程中(zhong)(zhong)也存在(zai)牙(ya)齒(chi)數(shu)量(liang)變(bian)化的(de)(de)(de)(de)(de)現(xian)象(xiang)。強(qiang)健(jian)懼龍(long)(long)最年輕(qing)(qing)的(de)(de)(de)(de)(de)個(ge)(ge)體(ti)(ti)(ti)(TMP 1994.143.0001)具有13顆(ke)上(shang)頜骨齒(chi),更大一(yi)點(dian)的(de)(de)(de)(de)(de)亞(ya)成體(ti)(ti)(ti)(AMNH 5346)有15或16顆(ke),而(er)再老一(yi)點(dian)的(de)(de)(de)(de)(de)個(ge)(ge)體(ti)(ti)(ti)會減(jian)少到14顆(ke)(NMC 8506)。這(zhe)種牙(ya)齒(chi)數(shu)量(liang)的(de)(de)(de)(de)(de)變(bian)化在(zai)霸王龍(long)(long)中(zhong)(zhong)也得到了證實(shi)。這(zhe)一(yi)研(yan)究(jiu)表明個(ge)(ge)體(ti)(ti)(ti)發育過(guo)程中(zhong)(zhong)的(de)(de)(de)(de)(de)牙(ya)齒(chi)數(shu)量(liang)先增(zeng)加再減(jian)少的(de)(de)(de)(de)(de)現(xian)象(xiang)可(ke)能廣泛存在(zai)于暴龍(long)(long)亞(ya)科中(zhong)(zhong)。
對(dui)于(yu)(yu)霍氏懼龍的(de)(de)研究發(fa)(fa)(fa)現,其(qi)面(mian)部紋飾也會隨(sui)著(zhu)個體(ti)發(fa)(fa)(fa)育(yu)(yu)階段(duan)的(de)(de)變(bian)化而變(bian)化,尤其(qi)是鼻骨的(de)(de)紋飾會隨(sui)著(zhu)年齡增大而減(jian)弱。這種現象(xiang)也見(jian)于(yu)(yu)霸王龍。對(dui)于(yu)(yu)角(jiao)龍類和腫(zhong)頭(tou)龍類的(de)(de)研究發(fa)(fa)(fa)現,頭(tou)部的(de)(de)裝(zhuang)飾也會隨(sui)著(zhu)個體(ti)發(fa)(fa)(fa)育(yu)(yu)而減(jian)弱。結(jie)合系統發(fa)(fa)(fa)育(yu)(yu)框架(jia)以(yi)及簡約性原則可以(yi)推測,頭(tou)部裝(zhuang)飾隨(sui)個體(ti)發(fa)(fa)(fa)育(yu)(yu)減(jian)弱是整個恐龍單系的(de)(de)共(gong)近裔(yi)特(te)征(zheng)。
對于懼(ju)龍(long)(long)(long)的(de)(de)(de)種群(qun)生(sheng)(sheng)物學研究發現,它與(yu)霸王(wang)龍(long)(long)(long),蛇(she)發女(nv)怪龍(long)(long)(long)和(he)阿(a)爾伯塔龍(long)(long)(long)具有(you)相似的(de)(de)(de)存活(huo)曲線,即(ji)較(jiao)低(di)的(de)(de)(de)新生(sheng)(sheng)個(ge)(ge)體存活(huo)率(lv),較(jiao)高(gao)(gao)的(de)(de)(de)幼年(nian)個(ge)(ge)體存活(huo)率(lv),以(yi)(yi)及(ji)從中年(nian)期開始死(si)亡率(lv)又再一次(ci)升高(gao)(gao)。懼(ju)龍(long)(long)(long)以(yi)(yi)及(ji)其(qi)它大(da)型(xing)暴(bao)龍(long)(long)(long)類的(de)(de)(de)群(qun)居性(xing)行為(wei)可(ke)能(neng)能(neng)夠有(you)效(xiao)降低(di)年(nian)輕(qing)個(ge)(ge)體的(de)(de)(de)死(si)亡率(lv)。同時大(da)型(xing)暴(bao)龍(long)(long)(long)類較(jiao)快(kuai)的(de)(de)(de)生(sheng)(sheng)長速度也能(neng)使它們的(de)(de)(de)幼體快(kuai)速度過(guo)危險(xian)期,達(da)到(dao)普通捕(bu)食者(zhe)無法捕(bu)食的(de)(de)(de)體型(xing)閾值(zhi)。而(er)同類相殘(can)行為(wei)可(ke)能(neng)是(shi)死(si)亡率(lv)從中年(nian)時期開始再度增加(jia)的(de)(de)(de)主要原因。
懼(ju)龍(long)(long)的(de)生活(huo)范圍與蛇發女怪龍(long)(long)有(you)所(suo)重疊。戴爾.羅素認為懼(ju)龍(long)(long)身體更為龐大,適合捕食防御能力較(jiao)(jiao)好的(de)角龍(long)(long)類(lei)(lei)(lei),而(er)蛇發女怪龍(long)(long)的(de)體態較(jiao)(jiao)為輕盈,適合捕食鴨嘴(zui)龍(long)(long)類(lei)(lei)(lei)。然(ran)(ran)而(er)一(yi)件懼(ju)龍(long)(long)標(biao)本的(de)胃容(rong)物里發現了幼年(nian)鴨嘴(zui)龍(long)(long)類(lei)(lei)(lei)的(de)殘骸。另外一(yi)種(zhong)可(ke)能是(shi)兩種(zhong)大型暴(bao)龍(long)(long)類(lei)(lei)(lei)雖然(ran)(ran)棲息在一(yi)片區域,但是(shi)它(ta)們生活(huo)的(de)微(wei)生境是(shi)不(bu)同的(de),因(yin)此兩者(zhe)可(ke)能沒有(you)太多(duo)的(de)機(ji)會(hui)見面打(da)架。
懼(ju)(ju)(ju)龍(long)(long)登(deng)場于BBC的(de)紀錄片(pian)(pian)《恐(kong)龍(long)(long)星球(qiu)》。在片(pian)(pian)中(zhong)(zhong),懼(ju)(ju)(ju)龍(long)(long)被描述(shu)為(wei)群居的(de)巨(ju)型殺手,依(yi)靠(kao)團隊合(he)作捕(bu)食(shi)落(luo)單的(de)開角(jiao)龍(long)(long),同(tong)時也會(hui)埋伏在尖角(jiao)龍(long)(long)群遷徙的(de)必經之(zhi)路上,伺機(ji)對獵物展開屠殺。懼(ju)(ju)(ju)龍(long)(long)還登(deng)場于Discovery的(de)同(tong)名紀錄片(pian)(pian)《恐(kong)龍(long)(long)星球(qiu)》中(zhong)(zhong)。片(pian)(pian)中(zhong)(zhong)的(de)懼(ju)(ju)(ju)龍(long)(long)會(hui)團隊合(he)作捕(bu)食(shi)慈(ci)母(mu)龍(long)(long),同(tong)時影片(pian)(pian)中(zhong)(zhong)還將(jiang)懼(ju)(ju)(ju)龍(long)(long)描述(shu)為(wei)霸王(wang)龍(long)(long)的(de)祖先(xian)。這(zhe)種描述(shu)是(shi)不(bu)嚴謹的(de),但依(yi)據現階段的(de)大多數系統發育分析(xi),如果除去亞洲的(de)諸(zhu)城暴(bao)(bao)龍(long)(long)和特暴(bao)(bao)龍(long)(long),懼(ju)(ju)(ju)龍(long)(long)確實是(shi)北美大型暴(bao)(bao)龍(long)(long)類中(zhong)(zhong)和霸王(wang)龍(long)(long)親緣(yuan)關系最近(jin)的(de)成員。
在暴(bao)龍(long)科(ke)中,達斯布雷龍(long)與特(te)暴(bao)龍(long)、暴(bao)龍(long)及(ji)分支龍(long)同屬于暴(bao)龍(long)亞(ya)科(ke)。暴(bao)龍(long)亞(ya)科(ke)的(de)物種都(dou)(dou)是較(jiao)接近(jin)暴(bao)龍(long),而較(jiao)不類似艾(ai)伯塔龍(long),特(te)征都(dou)(dou)是粗壯(zhuang)的(de)體型(xing)、比例上較(jiao)大的(de)頭(tou)顱骨、以(yi)及(ji)較(jiao)長的(de)股骨。
達斯(si)布(bu)雷(lei)(lei)(lei)龍(long)(long)(long)通(tong)常被(bei)(bei)認(ren)(ren)為是暴(bao)龍(long)(long)(long)的(de)(de)(de)近(jin)親,或是往暴(bao)龍(long)(long)(long)前進演(yan)化的(de)(de)(de)直接(jie)祖先(xian)。格里高利·保羅(Gregory S.Paul)曾將強健達斯(si)布(bu)雷(lei)(lei)(lei)龍(long)(long)(long)編入暴(bao)龍(long)(long)(long)屬中,但這(zhe)個(ge)分(fen)(fen)類(lei)卻一般不(bu)被(bei)(bei)接(jie)受(shou)。很(hen)多學者認(ren)(ren)為特暴(bao)龍(long)(long)(long)及暴(bao)龍(long)(long)(long)是姊妹(mei)分(fen)(fen)類(lei)單元(yuan),或甚(shen)至是同屬,而達斯(si)布(bu)雷(lei)(lei)(lei)龍(long)(long)(long)是這(zhe)個(ge)演(yan)化支的(de)(de)(de)基礎物種(zhong)。菲力·柯爾(Phil Currie)等人提出(chu)一個(ge)不(bu)同的(de)(de)(de)理論,分(fen)(fen)支龍(long)(long)(long)與特暴(bao)龍(long)(long)(long)這(zhe)兩個(ge)亞洲屬構成一個(ge)演(yan)化支,而達斯(si)布(bu)雷(lei)(lei)(lei)龍(long)(long)(long)較(jiao)接(jie)近(jin)這(zhe)個(ge)演(yan)化支,而離(li)北美洲的(de)(de)(de)暴(bao)龍(long)(long)(long)較(jiao)遠。要(yao)待(dai)所(suo)有的(de)(de)(de)達斯(si)布(bu)雷(lei)(lei)(lei)龍(long)(long)(long)物種(zhong)被(bei)(bei)研(yan)究、描(miao)述,才可以(yi)得到(dao)較(jiao)清晰的(de)(de)(de)達斯(si)布(bu)雷(lei)(lei)(lei)龍(long)(long)(long)分(fen)(fen)類(lei)關系。
對(dui)于(yu)現今(jin)的(de)獵食動物(wu)而(er)言,達(da)斯布雷龍體型非常巨大,相(xiang)當于(yu)一頭(tou)成(cheng)(cheng)年亞洲象的(de)大小。成(cheng)(cheng)年的(de)強健懼龍的(de)一般身長最大可(ke)達(da)10米(mi),平均體重估計約為4噸,最大個體可(ke)超過(guo)6噸。一個懼龍屬的(de)暫時未命名種超懼龍(暫時代稱)則(ze)可(ke)以達(da)到7.5噸重。
達(da)斯布(bu)雷(lei)龍(long)(long)(long)有巨大(da)的(de)(de)(de)頭(tou)(tou)顱骨(gu)(gu)(gu),約有1.1米長(chang)(chang)。頭(tou)(tou)顱骨(gu)(gu)(gu)的(de)(de)(de)構造(zao)特別(bie)堅固,例如口鼻(bi)部上的(de)(de)(de)鼻(bi)骨(gu)(gu)(gu)互相愈合(he),以增加強度,而頭(tou)(tou)骨(gu)(gu)(gu)的(de)(de)(de)大(da)型洞孔(kong)則(ze)可減低(di)重量。成年的(de)(de)(de)達(da)斯布(bu)雷(lei)龍(long)(long)(long)約有60多顆牙(ya)齒,每只牙(ya)齒都非常長(chang)(chang)而厚重。牙(ya)齒的(de)(de)(de)橫切面(mian)呈橢圓形而非短刃形。前上頜骨(gu)(gu)(gu)的(de)(de)(de)牙(ya)齒卻是(shi)呈D型的(de)(de)(de),這種異齒型在暴龍(long)(long)(long)科中(zhong)是(shi)非常普遍(bian)的(de)(de)(de)。達(da)斯布(bu)雷(lei)龍(long)(long)(long)頭(tou)(tou)顱骨(gu)(gu)(gu)的(de)(de)(de)獨特處在于,上頜骨(gu)(gu)(gu)的(de)(de)(de)表面(mian)凹(ao)凸不平(ping),以及眼睛周圍的(de)(de)(de)淚骨(gu)(gu)(gu)、眶后(hou)骨(gu)(gu)(gu)及顴(quan)骨(gu)(gu)(gu)有明顯的(de)(de)(de)隆起(qi)。眼窩呈長(chang)(chang)橢圓形,介于蛇發女怪龍(long)(long)(long)的(de)(de)(de)圓形及暴龍(long)(long)(long)的(de)(de)(de)鑰孔(kong)形之(zhi)間。吻(wen)部很寬,96厘米頭(tou)(tou)骨(gu)(gu)(gu)吻(wen)寬35厘米,最大(da)頭(tou)(tou)骨(gu)(gu)(gu)(超懼龍(long)(long)(long)唯一(yi)和最大(da)個體)137厘米吻(wen)寬可能達(da)到50厘米,吻(wen)寬比同體型的(de)(de)(de)霸王龍(long)(long)(long)都寬不少。
與(yu)(yu)其他的(de)(de)暴龍科都(dou)有著(zhu)相(xiang)似的(de)(de)體(ti)型,都(dou)是(shi)由(you)呈(cheng)S型的(de)(de)頸部(bu)(bu)支撐著(zhu)沉(chen)重的(de)(de)頭(tou)部(bu)(bu)。它的(de)(de)前肢(zhi)非常(chang)的(de)(de)短(duan)小,只有二指(zhi),不過在暴龍亞科中(zhong),達斯(si)布(bu)雷龍的(de)(de)前肢(zhi)與(yu)(yu)身體(ti)比例(li)是(shi)目前發現最長的(de)(de)。達斯(si)布(bu)雷龍具有兩個巨大而(er)長后肢(zhi),上有四趾(zhi),第一趾(zhi)為反(fan)爪,無(wu)法接觸地面。達斯(si)布(bu)雷龍具有長及重的(de)(de)尾巴,可平衡頭(tou)部(bu)(bu)與(yu)(yu)胸部(bu)(bu),使重心位在臀部(bu)(bu)上。
目前科學家表明,同體型的情況(kuang)下,達(da)斯布(bu)雷龍攻擊力不亞于(yu)霸王龍。
達斯(si)布(bu)雷(lei)龍(屬名(ming):Daspletosaurus)又名(ming)懼龍。是暴(bao)龍科下(xia)的(de)(de)一(yi)屬恐龍。它(ta)(ta)們極少群居,大(da)多是零零散(san)(san)散(san)(san)的(de)(de)分布(bu)在(zai)(zai)各處(chu)。只有(you)在(zai)(zai)遷移或(huo)遠行時(shi)才有(you)例外。它(ta)(ta)們有(you)時(shi)住(zhu)在(zai)(zai)山林中(zhong)(zhong)的(de)(de)洞穴里、有(you)時(shi)住(zhu)在(zai)(zai)濃密(mi)的(de)(de)叢林中(zhong)(zhong),它(ta)(ta)們是以突襲的(de)(de)方式獵捕(bu)食物。它(ta)(ta)用那粗大(da)有(you)力的(de)(de)尾巴橫(heng)掃獵物,將其一(yi)口咬住(zhu)。
達斯布雷龍的(de)棲息環(huan)境很廣,主要(yao)分布在樹林、山谷、溪邊,它不喜(xi)歡在山上,因為這樣不善于奔(ben)跑。
繁殖方(fang)式跟別的恐龍一樣,也是通過產卵(luan)方(fang)式繁殖。
強(qiang)健(jian)達(da)斯(si)(si)(si)布雷龍(long)(Daspletosaurus torosus)的(de)(de)(de)(de)(de)模式標本(ben)(ben)是(shi)(shi)一個完(wan)整(zheng)性約(yue)75%的(de)(de)(de)(de)(de)骨(gu)(gu)骼(ge),包括了(le)(le)完(wan)整(zheng)的(de)(de)(de)(de)(de)頭顱骨(gu)(gu)、幾(ji)乎完(wan)整(zheng)的(de)(de)(de)(de)(de)頸椎、完(wan)整(zheng)的(de)(de)(de)(de)(de)脊椎骨(gu)(gu)、前11節(jie)尾椎、肩膀(bang)、一個完(wan)整(zheng)的(de)(de)(de)(de)(de)前肢、骨(gu)(gu)盆及兩根股骨(gu)(gu)。這些(xie)化石是(shi)(shi)于(yu)(yu)1921年(nian)由查爾斯(si)(si)(si)·斯(si)(si)(si)騰(teng)伯格(Charles Mortram Sternberg)所發(fa)現(xian)(xian)(xian),他最初認為這些(xie)化石屬于(yu)(yu)蛇發(fa)女(nv)怪龍(long)的(de)(de)(de)(de)(de)一個新(xin)(xin)種(zhong)。但是(shi)(shi),這些(xie)標本(ben)(ben)要直到1970年(nian)才由戴(dai)爾·羅素(Dale Russell)完(wan)全的(de)(de)(de)(de)(de)描述,并建立新(xin)(xin)的(de)(de)(de)(de)(de)達(da)斯(si)(si)(si)布雷龍(long)屬。達(da)斯(si)(si)(si)布雷龍(long)的(de)(de)(de)(de)(de)學名(ming)是(shi)(shi)由古希(xi)臘文的(de)(de)(de)(de)(de)"δασπλητo-"(意(yi)即"懼(ju)怕")及"σαυρο?"(意(yi)即"蜥蜴")組合而(er)來。種(zhong)名(ming)的(de)(de)(de)(de)(de)torosus是(shi)(shi)一拉(la)丁文,意(yi)指"強(qiang)壯(zhuang)"或(huo)"結(jie)實"。除了(le)(le)模式標本(ben)(ben),在2001年(nian)發(fa)現(xian)(xian)(xian)一個完(wan)整(zheng)的(de)(de)(de)(de)(de)達(da)斯(si)(si)(si)布雷龍(long)骨(gu)(gu)骼(ge)標本(ben)(ben)。這兩個標本(ben)(ben)都(dou)是(shi)(shi)來自加(jia)拿大的(de)(de)(de)(de)(de)阿(a)爾伯塔省,發(fa)現(xian)(xian)(xian)于(yu)(yu)朱迪斯(si)(si)(si)河(he)群中(zhong)的(de)(de)(de)(de)(de)奧爾德(de)曼組。另一個年(nian)代較晚的(de)(de)(de)(de)(de)馬蹄(ti)峽谷組發(fa)現(xian)(xian)(xian)的(de)(de)(de)(de)(de)標本(ben)(ben),被重新(xin)(xin)歸類(lei)于(yu)(yu)艾(ai)伯塔龍(long)。奧爾德(de)曼組是(shi)(shi)在上(shang)白堊紀的(de)(de)(de)(de)(de)坎帕階中(zhong)期形成的(de)(de)(de)(de)(de),距今(jin)約(yue)有7700萬(wan)-7600萬(wan)年(nian)前。
在(zai)(zai)建(jian)立(li)強健達(da)(da)斯(si)(si)布雷(lei)(lei)龍(long)(long)的(de)(de)(de)正(zheng)模標(biao)本時,羅素將由巴納(na)姆·布郎(lang)(lang)(Barnum Brown)于(yu)1913年(nian)所挖(wa)掘的(de)(de)(de)標(biao)本,建(jian)立(li)為(wei)強健達(da)(da)斯(si)(si)布雷(lei)(lei)龍(long)(long)的(de)(de)(de)副模標(biao)本。這個(ge)標(biao)本包含了一個(ge)骨(gu)(gu)盆、部份(fen)后肢、及(ji)一些相(xiang)連的(de)(de)(de)脊(ji)椎,是發(fa)現于(yu)阿爾(er)(er)伯(bo)塔(ta)省的(de)(de)(de)奧爾(er)(er)德(de)(de)曼組的(de)(de)(de)較(jiao)(jiao)上(shang)(shang)層。這個(ge)較(jiao)(jiao)上(shang)(shang)層后被更名為(wei)恐(kong)(kong)龍(long)(long)公園(yuan)(yuan)(yuan)組,屬于(yu)坎(kan)帕階晚期,距(ju)今7600萬(wan)-7400萬(wan)年(nian)前。于(yu)1914年(nian),布郎(lang)(lang)從(cong)同一地(di)層發(fa)現接近完整(zheng)的(de)(de)(de)骨(gu)(gu)骼(ge)及(ji)頭顱(lu)骨(gu)(gu),并(bing)于(yu)40年(nian)后由美(mei)國(guo)自然歷(li)史博物(wu)館(guan)售(shou)予(yu)芝加哥的(de)(de)(de)菲(fei)爾(er)(er)德(de)(de)自然歷(li)史博物(wu)館(guan)。這顱(lu)骨(gu)(gu)目前在(zai)(zai)芝加哥菲(fei)爾(er)(er)德(de)(de)博物(wu)館(guan)展出(chu)(chu)中,并(bing)多(duo)年(nian)以來都(dou)被歸類為(wei)是"Albertosaurus libratus"。但在(zai)(zai)發(fa)現幾個(ge)頭顱(lu)骨(gu)(gu)特征(zheng)(包括(kuo)大部份(fen)的(de)(de)(de)牙齒(chi))被石膏隱(yin)藏多(duo)年(nian)后,這個(ge)標(biao)本才被重置(zhi)在(zai)(zai)達(da)(da)斯(si)(si)布雷(lei)(lei)龍(long)(long)屬中。在(zai)(zai)恐(kong)(kong)龍(long)(long)公園(yuan)(yuan)(yuan)組一共發(fa)現了八具標(biao)本,大部份(fen)都(dou)是在(zai)(zai)恐(kong)(kong)龍(long)(long)省立(li)公園(yuan)(yuan)(yuan)的(de)(de)(de)范圍內(nei)。菲(fei)力(li)·柯爾(er)(er)(Phil Currie)發(fa)現恐(kong)(kong)龍(long)(long)公園(yuan)(yuan)(yuan)標(biao)本的(de)(de)(de)頭顱(lu)骨(gu)(gu)上(shang)(shang)有一些不同的(de)(de)(de)特征(zheng),認為(wei)這代表一個(ge)新的(de)(de)(de)達(da)(da)斯(si)(si)布雷(lei)(lei)龍(long)(long)物(wu)種(zhong)(zhong)。這個(ge)新物(wu)種(zhong)(zhong)的(de)(de)(de)圖畫經已(yi)被出(chu)(chu)版,但仍有待(dai)正(zheng)式的(de)(de)(de)命名及(ji)描述。
在1990年(nian),新(xin)墨西(xi)哥(ge)州的嘉(jia)德蘭組發現了一個新(xin)的暴龍(long)科標本,包括頭(tou)顱骨碎片、肋骨及部份(fen)后(hou)肢,被編(bian)入后(hou)彎齒龍(long),后(hou)彎齒龍(long)的狀(zhuang)態是個疑名。后(hou)來很多學者(zhe)都將這(zhe)個標本,連(lian)同一些其(qi)他新(xin)墨西(xi)哥(ge)州發現的化石,重(zhong)新(xin)歸類于(yu)達斯布雷龍(long)屬(shu)中的未(wei)命名種。在2010年(nian)的一個研(yan)究(jiu),認為(wei)(wei)這(zhe)個新(xin)墨西(xi)哥(ge)物種,其(qi)實是早(zao)(zao)期的暴龍(long)科,并(bing)建立為(wei)(wei)新(xin)屬(shu),Bistahieversor。目前對嘉(jia)德蘭組的年(nian)代有所爭議(yi),一些研(yan)究(jiu)指出其(qi)年(nian)代屬(shu)于(yu)坎帕階(jie)晚期,而(er)其(qi)他研(yan)究(jiu)則認為(wei)(wei)是麥斯特里希特階(jie)早(zao)(zao)期。
于(yu)1992年,杰克(ke)·霍納(na)(Jack Horner)及(ji)(ji)他的(de)(de)同僚(liao)發(fa)(fa)表一(yi)(yi)份有(you)(you)關美(mei)國蒙(meng)大拿州雙(shuang)(shuang)麥(mai)迪(di)遜組較(jiao)上層的(de)(de)新發(fa)(fa)現暴(bao)(bao)龍(long)(long)科恐龍(long)(long)的(de)(de)初步報告,認(ren)為(wei)這(zhe)些新化(hua)石是(shi)達斯(si)布(bu)雷(lei)(lei)龍(long)(long)及(ji)(ji)后期暴(bao)(bao)龍(long)(long)的(de)(de)過(guo)渡物種(zhong),其年代為(wei)坎潘階。在2001年,雙(shuang)(shuang)麥(mai)迪(di)遜組的(de)(de)上層發(fa)(fa)現另一(yi)(yi)個部(bu)份骨骼,在其下腹內保(bao)存(cun)了一(yi)(yi)頭鴨嘴龍(long)(long)科的(de)(de)幼年個體化(hua)石。這(zhe)個標(biao)本(ben)被(bei)歸類于(yu)達斯(si)布(bu)雷(lei)(lei)龍(long)(long)的(de)(de)一(yi)(yi)種(zhong),但卻沒(mei)(mei)有(you)(you)明定是(shi)哪一(yi)(yi)個種(zhong)。在雙(shuang)(shuang)麥(mai)迪(di)遜的(de)(de)骨床中(zhong)(zhong),曾發(fa)(fa)現最(zui)少三個以上的(de)(de)達斯(si)布(bu)雷(lei)(lei)龍(long)(long)化(hua)石。這(zhe)些標(biao)本(ben)都(dou)沒(mei)(mei)有(you)(you)被(bei)詳細描述,但柯(ke)爾(er)認(ren)為(wei)所(suo)有(you)(you)的(de)(de)雙(shuang)(shuang)麥(mai)迪(di)遜化(hua)石都(dou)是(shi)達斯(si)布(bu)雷(lei)(lei)龍(long)(long)屬中(zhong)(zhong)的(de)(de)第三個未被(bei)命名種(zhong)。
雖(sui)然達斯布雷龍(long)(long)的(de)(de)(de)化(hua)石并不(bu)像著名的(de)(de)(de)近親霸王龍(long)(long)那樣地(di)驚(jing)人(ren)地(di)常(chang)見和普遍被(bei)發現,但都足以讓古生物(wu)學家來研究(jiu)其生物(wu)學的(de)(de)(de)某些(xie)范疇。目(mu)前至少發現了14個標本(ben),不(bu)算上零碎的(de)(de)(de)骨骼碎片和私(si)人(ren)收藏家的(de)(de)(de)化(hua)石。
于坎帕階(jie)晚期的(de)北(bei)美(mei)洲(zhou),達斯布雷龍(long)與(yu)蛇(she)發女(nv)怪龍(long)生(sheng)存(cun)于相(xiang)同(tong)時(shi)代的(de)相(xiang)同(tong)地區。這是少(shao)數兩(liang)個暴龍(long)科的(de)屬共存(cun)的(de)例子(zi)。在現(xian)今的(de)獵(lie)食動物(wu)中(zhong),體型相(xiang)似(si)的(de)獵(lie)食動物(wu)因(yin)為解(jie)剖學、行為或地理的(de)原(yuan)因(yin),會區分成不同(tong)的(de)生(sheng)態位,以(yi)限制競(jing)爭。有(you)幾個研(yan)究嘗試解(jie)釋達斯布雷龍(long)及(ji)蛇(she)發女(nv)怪龍(long)的(de)生(sheng)態位差異。
戴爾·羅素假設較輕盈(ying)、常見的蛇發女怪龍(long)可能獵食當時繁盛的鴨嘴龍(long)科(ke)(ke)(ke),而較強壯、稀少(shao)的達(da)斯(si)布(bu)雷(lei)龍(long)則(ze)專門獵食數量較小、防御(yu)較好的角(jiao)龍(long)科(ke)(ke)(ke)。但(dan)是(shi),在(zai)(zai)雙麥迪遜組發現的達(da)斯(si)布(bu)雷(lei)龍(long)標本(ben),在(zai)(zai)其胃部(bu)保存了鴨嘴龍(long)科(ke)(ke)(ke)幼(you)年(nian)體(ti)的已(yi)消化化石。暴龍(long)亞科(ke)(ke)(ke)(例(li)如(ru)達(da)斯(si)布(bu)雷(lei)龍(long))有(you)著較高(gao)及較寬的口鼻部(bu),比有(you)較低口鼻部(bu)的艾伯塔龍(long)亞科(ke)(ke)(ke)(例(li)如(ru)蛇發女怪龍(long))更為(wei)強壯,不(bu)過(guo)牙齒的強度則(ze)差異不(bu)大。這顯示兩(liang)者(zhe)在(zai)(zai)攝食的技巧(qiao)或食性都有(you)所不(bu)同(tong)。
其(qi)他(ta)學者認為它(ta)們之間的(de)(de)競爭受到地理(li)區(qu)分(fen)(fen)的(de)(de)限制。不像其(qi)他(ta)的(de)(de)恐(kong)龍(long)(long)類(lei),它(ta)們的(de)(de)區(qu)分(fen)(fen)似(si)(si)(si)乎(hu)與(yu)離海岸的(de)(de)距離沒有(you)關(guan)聯(lian),而也與(yu)海拔高或低無關(guan)。但是,雖然生活區(qu)域(yu)有(you)部(bu)(bu)分(fen)(fen)的(de)(de)重疊,蛇發(fa)女怪龍(long)(long)似(si)(si)(si)乎(hu)在北方較為普遍,而達斯布雷龍(long)(long)則傾向于南方。其(qi)他(ta)的(de)(de)恐(kong)龍(long)(long)亦有(you)類(lei)似(si)(si)(si)的(de)(de)地理(li)分(fen)(fen)布。在坎潘階,鴨(ya)嘴龍(long)(long)亞(ya)科(ke)與(yu)開(kai)角(jiao)龍(long)(long)亞(ya)科(ke)繁盛于雙麥迪遜組與(yu)北美(mei)洲西(xi)南部(bu)(bu)。湯瑪斯·荷茲(Thomas Holtz)指出這個地理(li)分(fen)(fen)布型式,顯(xian)示暴(bao)龍(long)(long)亞(ya)科(ke)、開(kai)角(jiao)龍(long)(long)亞(ya)科(ke)及鴨(ya)嘴龍(long)(long)亞(ya)科(ke)都(dou)有(you)著同樣的(de)(de)生態位傾向。他(ta)認為于麥斯特(te)里希特(te)階末期,暴(bao)龍(long)(long)亞(ya)科(ke)(如(ru)(ru)暴(bao)龍(long)(long))、鴨(ya)嘴龍(long)(long)亞(ya)科(ke)及開(kai)角(jiao)龍(long)(long)亞(ya)科(ke)(如(ru)(ru)三角(jiao)龍(long)(long))廣泛分(fen)(fen)布在北美(mei)洲西(xi)部(bu)(bu),而艾(ai)伯塔(ta)龍(long)(long)亞(ya)科(ke)及尖角(jiao)龍(long)(long)亞(ya)科(ke)已滅(mie)絕,賴(lai)氏龍(long)(long)亞(ya)科(ke)則已很稀少。
在恐龍(long)(long)公園地(di)層(ceng)發(fa)現(xian)(xian)的(de)(de)(de)一(yi)個年(nian)輕(qing)達斯(si)布雷龍(long)(long)標本,面部上有被其他暴(bao)龍(long)(long)科咬傷的(de)(de)(de)痕跡。這(zhe)(zhe)個咬痕已經痊愈,顯(xian)示它在這(zhe)(zhe)次事(shi)件后存活過(guo)來。在同(tong)一(yi)地(di)層(ceng)發(fa)現(xian)(xian)的(de)(de)(de)一(yi)個成年(nian)達斯(si)布雷龍(long)(long)標本也有相似(si)咬痕,可(ke)見這(zhe)(zhe)類(lei)攻(gong)(gong)擊并不限于年(nian)輕(qing)的(de)(de)(de)動(dong)物(wu)(wu)。雖然這(zhe)(zhe)些攻(gong)(gong)擊可(ke)能是來自其他物(wu)(wu)種(zhong),但獵(lie)食(shi)(shi)動(dong)物(wu)(wu)常(chang)發(fa)生物(wu)(wu)種(zhong)內的(de)(de)(de)打斗(dou)、攻(gong)(gong)擊行為(wei)。目(mu)前已在其他的(de)(de)(de)暴(bao)龍(long)(long)科(如蛇發(fa)女怪龍(long)(long)及(ji)暴(bao)龍(long)(long))以及(ji)其他的(de)(de)(de)獸腳亞目(mu)(如中(zhong)華盜龍(long)(long)及(ji)蜥鳥盜龍(long)(long))發(fa)現(xian)(xian)這(zhe)(zhe)種(zhong)面部的(de)(de)(de)攻(gong)(gong)擊痕跡。Darren Tanke與菲力(li)·柯爾(Phil Currie)提出假(jia)說,指出這(zhe)(zhe)些攻(gong)(gong)擊是因為(wei)競爭(zheng)疆(jiang)域、食(shi)(shi)物(wu)(wu)資源、或支配(pei)群族而出現(xian)(xian)的(de)(de)(de)種(zhong)內競爭(zheng)。
達斯(si)布雷(lei)(lei)龍(long)(long)(long)群體(ti)(ti)生活(huo)的(de)(de)(de)證(zheng)據(ju)(ju)是發(fa)現(xian)于蒙(meng)大(da)拿州雙麥(mai)迪(di)遜組骨(gu)床的(de)(de)(de)化石。骨(gu)床內有三(san)頭達斯(si)布雷(lei)(lei)龍(long)(long)(long)的(de)(de)(de)遺(yi)(yi)骸,包括一(yi)頭大(da)的(de)(de)(de)成(cheng)年個體(ti)(ti)、一(yi)頭小的(de)(de)(de)幼龍(long)(long)(long)、及另一(yi)頭中(zhong)型(xing)(xing)大(da)小的(de)(de)(de)達斯(si)布雷(lei)(lei)龍(long)(long)(long)。同一(yi)地(di)(di)點還(huan)發(fa)現(xian)最少五頭鴨嘴龍(long)(long)(long)科(ke)化石。地(di)(di)質學證(zheng)據(ju)(ju)顯(xian)示,這些(xie)遺(yi)(yi)骸并(bing)(bing)非被河流沖積在一(yi)起,而是在短暫時間遭到集體(ti)(ti)掩葬。鴨嘴龍(long)(long)(long)科(ke)的(de)(de)(de)遺(yi)(yi)骸是分散(san)的(de)(de)(de),并(bing)(bing)且有很(hen)多暴龍(long)(long)(long)科(ke)牙齒的(de)(de)(de)咬痕,可見達斯(si)布雷(lei)(lei)龍(long)(long)(long)在死前曾吃(chi)過這些(xie)鴨嘴龍(long)(long)(long)科(ke)動物。這些(xie)動物的(de)(de)(de)死亡原因并(bing)(bing)不(bu)清楚。菲(fei)力(li)·柯爾猜測(ce)達斯(si)布雷(lei)(lei)龍(long)(long)(long)是群體(ti)(ti)狩獵的(de)(de)(de),但無法確定。其(qi)他科(ke)學家則對達斯(si)布雷(lei)(lei)龍(long)(long)(long)及其(qi)他大(da)型(xing)(xing)獸腳(jiao)亞目的(de)(de)(de)群體(ti)(ti)活(huo)動證(zheng)據(ju)(ju)抱有懷疑。
古生(sheng)物學家格里高(gao)(gao)利·艾(ai)利克森(sen)(sen)(Gregory Erickson)及(ji)(ji)其同僚研(yan)究了暴龍(long)(long)(long)科的(de)(de)(de)(de)生(sheng)長(chang)(chang)及(ji)(ji)壽命(ming)。透過骨頭組織學的(de)(de)(de)(de)分析,可以確(que)定標本(ben)死亡時的(de)(de)(de)(de)年(nian)(nian)齡。將不(bu)同個(ge)(ge)體(ti)的(de)(de)(de)(de)年(nian)(nian)齡與(yu)體(ti)型繪(hui)制為圖表,就可得到(dao)生(sheng)長(chang)(chang)曲(qu)線。艾(ai)利克森(sen)(sen)指出(chu)暴龍(long)(long)(long)科經(jing)歷長(chang)(chang)時間的(de)(de)(de)(de)幼龍(long)(long)(long)狀態,會在4年(nian)(nian)內急(ji)速成(cheng)長(chang)(chang)。這個(ge)(ge)急(ji)速成(cheng)長(chang)(chang)的(de)(de)(de)(de)階段會在達(da)(da)(da)到(dao)性(xing)成(cheng)熟時完結,成(cheng)年(nian)(nian)后(hou)的(de)(de)(de)(de)生(sheng)長(chang)(chang)率(lv)會減慢。艾(ai)利克森(sen)(sen)只(zhi)研(yan)究了從雙麥迪遜組發現的(de)(de)(de)(de)達(da)(da)(da)斯布(bu)(bu)(bu)(bu)雷(lei)(lei)龍(long)(long)(long)標本(ben),但這些標本(ben)都有(you)相(xiang)同的(de)(de)(de)(de)生(sheng)長(chang)(chang)模式。與(yu)艾(ai)伯塔龍(long)(long)(long)相(xiang)比(bi),因達(da)(da)(da)斯布(bu)(bu)(bu)(bu)雷(lei)(lei)龍(long)(long)(long)的(de)(de)(de)(de)體(ti)重較高(gao)(gao),在急(ji)速成(cheng)長(chang)(chang)期有(you)著較快(kuai)的(de)(de)(de)(de)生(sheng)長(chang)(chang)率(lv)。達(da)(da)(da)斯布(bu)(bu)(bu)(bu)雷(lei)(lei)龍(long)(long)(long)的(de)(de)(de)(de)最大(da)生(sheng)長(chang)(chang)率(lv)為每(mei)年(nian)(nian)180公斤(假設(she)成(cheng)年(nian)(nian)的(de)(de)(de)(de)達(da)(da)(da)斯布(bu)(bu)(bu)(bu)雷(lei)(lei)龍(long)(long)(long)體(ti)重是3500公斤)。其他學者指出(chu)達(da)(da)(da)斯布(bu)(bu)(bu)(bu)雷(lei)(lei)龍(long)(long)(long)應為更重,不(bu)過這只(zhi)會影響達(da)(da)(da)斯布(bu)(bu)(bu)(bu)雷(lei)(lei)龍(long)(long)(long)生(sheng)長(chang)(chang)率(lv)的(de)(de)(de)(de)量,而非(fei)整(zheng)體(ti)模式。
艾(ai)(ai)利克森等人將每一(yi)個(ge)年齡層的(de)(de)(de)(de)(de)標(biao)本作成(cheng)表(biao)格,整理(li)出(chu)艾(ai)(ai)伯(bo)塔(ta)龍群(qun)族的(de)(de)(de)(de)(de)生長(chang)模(mo)式(shi)。艾(ai)(ai)利克森指出(chu)艾(ai)(ai)伯(bo)塔(ta)龍的(de)(de)(de)(de)(de)幼(you)年個(ge)體(ti)化石(shi)(shi)紀錄較為稀少,處(chu)在(zai)急速成(cheng)長(chang)期(qi)的(de)(de)(de)(de)(de)接(jie)近成(cheng)年個(ge)體(ti)及成(cheng)年個(ge)體(ti)則(ze)更為常(chang)見。這可能是因(yin)(yin)為化石(shi)(shi)化過程與挖掘(jue)化石(shi)(shi)的(de)(de)(de)(de)(de)偏差(cha)(cha)。艾(ai)(ai)利克森假設(she)這些差(cha)(cha)異是來(lai)自幼(you)龍在(zai)某一(yi)體(ti)型(xing)(xing)的(de)(de)(de)(de)(de)低(di)死亡率,就(jiu)像(xiang)現(xian)(xian)今(jin)的(de)(de)(de)(de)(de)某些大型(xing)(xing)哺乳類(例如象)一(yi)樣。因(yin)(yin)為暴(bao)龍科在(zai)兩歲時(shi)體(ti)型(xing)(xing)就(jiu)超越了所有同期(qi)的(de)(de)(de)(de)(de)獵食(shi)動物,所以在(zai)缺(que)乏被獵食(shi)的(de)(de)(de)(de)(de)情(qing)況(kuang)下(xia),出(chu)現(xian)(xian)低(di)死亡率。古生物學(xue)家并沒有足夠(gou)的(de)(de)(de)(de)(de)達(da)斯布(bu)(bu)雷龍化石(shi)(shi)來(lai)進行類似的(de)(de)(de)(de)(de)分析,但艾(ai)(ai)利克森則(ze)認為達(da)斯布(bu)(bu)雷龍也有類似的(de)(de)(de)(de)(de)生長(chang)趨(qu)勢。
目前已發(fa)現(xian)的達(da)(da)斯(si)布雷(lei)龍(long)(long)化石都發(fa)現(xian)于上(shang)白堊紀坎帕階(jie)中至(zhi)晚期(qi)的地層,距今(jin)約7700萬-7400萬年前。在白堊紀中期(qi),北美洲被西(xi)(xi)部內陸海(hai)道(dao)一(yi)分為(wei)二,蒙大(da)(da)(da)拿州及(ji)阿爾伯塔省大(da)(da)(da)部份都在海(hai)平面之下。在這(zhe)段達(da)(da)斯(si)布雷(lei)龍(long)(long)存活的時(shi)期(qi),西(xi)(xi)部拉拉米造山運動使得落基山脈(mo)隆起,使海(hai)道(dao)向(xiang)東方及(ji)南方后(hou)退。大(da)(da)(da)型(xing)河流從西(xi)(xi)側的山脈(mo)流至(zhi)東側的海(hai)道(dao),當中的沉(chen)積物形成廣大(da)(da)(da)的海(hai)岸平原,成為(wei)朱迪斯(si)河群的雙(shuang)麥迪遜組與其(qi)他的地層。約7300萬年前,海(hai)道(dao)再次向(xiang)西(xi)(xi)方與北方海(hai)侵,逐漸淹沒恐龍(long)(long)公園組,涵蓋美國西(xi)(xi)部及(ji)加拿大(da)(da)(da)西(xi)(xi)部。
達斯布雷龍生(sheng)活在西(xi)部內陸(lu)海(hai)(hai)道西(xi)岸(an)的(de)(de)(de)(de)(de)(de)(de)(de)廣大(da)沖積(ji)平原。大(da)型的(de)(de)(de)(de)(de)(de)(de)(de)河(he)(he)流流經土地,有(you)時(shi)會出現泛濫(lan),形(xing)成(cheng)新的(de)(de)(de)(de)(de)(de)(de)(de)沉(chen)積(ji)層(ceng)。當水源充(chong)足時(shi),可以維持大(da)量的(de)(de)(de)(de)(de)(de)(de)(de)植物(wu)及(ji)動(dong)物(wu)生(sheng)活,但這個(ge)區(qu)(qu)(qu)域會發生(sheng)周(zhou)期性(xing)的(de)(de)(de)(de)(de)(de)(de)(de)干旱(han),造(zao)成(cheng)大(da)量生(sheng)物(wu)的(de)(de)(de)(de)(de)(de)(de)(de)死亡(wang),形(xing)成(cheng)朱迪(di)(di)斯河(he)(he)群(qun)(qun)與(yu)雙(shuang)麥迪(di)(di)遜組的(de)(de)(de)(de)(de)(de)(de)(de)眾多(duo)骨床。在現今的(de)(de)(de)(de)(de)(de)(de)(de)東非也有(you)相(xiang)(xiang)似(si)的(de)(de)(de)(de)(de)(de)(de)(de)情(qing)況(kuang)。平原西(xi)方的(de)(de)(de)(de)(de)(de)(de)(de)周(zhou)期性(xing)火山噴發,產生(sheng)的(de)(de)(de)(de)(de)(de)(de)(de)火山灰(hui)會影響整個(ge)地區(qu)(qu)(qu),這成(cheng)大(da)量的(de)(de)(de)(de)(de)(de)(de)(de)死亡(wang),而同(tong)時(shi)豐富了(le)土壤(rang),有(you)助于日(ri)后的(de)(de)(de)(de)(de)(de)(de)(de)植物(wu)生(sheng)長。科學(xue)家(jia)也借(jie)由這些火山灰(hui)得(de)出準確的(de)(de)(de)(de)(de)(de)(de)(de)放射性(xing)測年。海(hai)(hai)平面的(de)(de)(de)(de)(de)(de)(de)(de)改(gai)變,在不同(tong)時(shi)期對朱迪(di)(di)斯河(he)(he)群(qun)(qun)的(de)(de)(de)(de)(de)(de)(de)(de)不同(tong)地區(qu)(qu)(qu),造(zao)成(cheng)許(xu)多(duo)環境(jing)變動(dong),包括(kuo)離岸(an)及(ji)近岸(an)的(de)(de)(de)(de)(de)(de)(de)(de)海(hai)(hai)洋生(sheng)態(tai)、海(hai)(hai)岸(an)濕地、三角洲(zhou)及(ji)礁(jiao)湖、內陸(lu)的(de)(de)(de)(de)(de)(de)(de)(de)泛濫(lan)平原等。與(yu)朱迪(di)(di)斯河(he)(he)群(qun)(qun)的(de)(de)(de)(de)(de)(de)(de)(de)其他地層(ceng)相(xiang)(xiang)比,雙(shuang)麥迪(di)(di)遜組是在更內陸(lu)的(de)(de)(de)(de)(de)(de)(de)(de)高海(hai)(hai)拔地區(qu)(qu)(qu)。
在雙麥迪遜組及(ji)(ji)(ji)朱迪斯河(he)群(qun)(qun)有(you)(you)良好的(de)(de)脊(ji)椎(zhui)動(dong)物(wu)(wu)(wu)(wu)化(hua)石(shi)(shi)紀錄(lu),這(zhe)是因為豐(feng)富的(de)(de)動(dong)物(wu)(wu)(wu)(wu)群(qun)(qun)、周期性的(de)(de)自然災害及(ji)(ji)(ji)大量的(de)(de)沉(chen)積巖所(suo)造成的(de)(de)。這(zhe)些(xie)地區(qu)有(you)(you)多樣(yang)性的(de)(de)淡水(shui)及(ji)(ji)(ji)入海(hai)口魚(yu)(yu)類化(hua)石(shi)(shi),包(bao)括鯊魚(yu)(yu)、鰩目、鱘魚(yu)(yu)、雀鱔(shan)目及(ji)(ji)(ji)其他(ta)魚(yu)(yu)類。朱迪斯河(he)群(qun)(qun)也保存(cun)很多水(shui)生爬(pa)(pa)行(xing)動(dong)物(wu)(wu)(wu)(wu)及(ji)(ji)(ji)兩(liang)棲(qi)動(dong)物(wu)(wu)(wu)(wu)化(hua)石(shi)(shi),包(bao)括有(you)(you)青蛙、鯢、龜、鱷龍(long)(long)及(ji)(ji)(ji)鱷魚(yu)(yu)。陸地上的(de)(de)爬(pa)(pa)行(xing)動(dong)物(wu)(wu)(wu)(wu),則(ze)有(you)(you)叉(cha)舌蜥科(ke)、石(shi)(shi)龍(long)(long)子(zi)科(ke)、巨蜥科(ke)及(ji)(ji)(ji)蛇(she)蜥科(ke)。天空(kong)的(de)(de)飛行(xing)動(dong)物(wu)(wu)(wu)(wu)則(ze)包(bao)含:神龍(long)(long)翼龍(long)(long)科(ke)及(ji)(ji)(ji)新鳥亞(ya)綱(如虛(xu)椎(zhui)鳥等)。哺乳(ru)動(dong)物(wu)(wu)(wu)(wu)則(ze)包(bao)含:多瘤齒目、有(you)(you)袋目及(ji)(ji)(ji)真獸類哺乳(ru)動(dong)物(wu)(wu)(wu)(wu)。除此(ci)上述(shu)物(wu)(wu)(wu)(wu)種(zhong)之(zhi)外(wai),還有(you)(you)達斯布雷龍(long)(long)及(ji)(ji)(ji)其他(ta)恐龍(long)(long)。
在(zai)奧爾德(de)曼組(zu),強健達斯布雷龍(long)(long)(long)(long)(long)(long)可能獵食鴨嘴龍(long)(long)(long)(long)(long)(long)科(ke)(ke)(ke)(如短冠龍(long)(long)(long)(long)(long)(long)及(ji)亞(ya)冠龍(long)(long)(long)(long)(long)(long))、小型的鳥(niao)腳下(xia)(xia)目(mu)(如奔山龍(long)(long)(long)(long)(long)(long))、角龍(long)(long)(long)(long)(long)(long)科(ke)(ke)(ke)(如尖角龍(long)(long)(long)(long)(long)(long))、腫頭(tou)龍(long)(long)(long)(long)(long)(long)下(xia)(xia)目(mu)、似鳥(niao)龍(long)(long)(long)(long)(long)(long)下(xia)(xia)目(mu)、鐮刀(dao)龍(long)(long)(long)(long)(long)(long)超科(ke)(ke)(ke)及(ji)甲龍(long)(long)(long)(long)(long)(long)下(xia)(xia)目(mu)。其他獵食恐龍(long)(long)(long)(long)(long)(long)包(bao)括:傷齒龍(long)(long)(long)(long)(long)(long)科(ke)(ke)(ke)、竊蛋龍(long)(long)(long)(long)(long)(long)下(xia)(xia)目(mu)、馳龍(long)(long)(long)(long)(long)(long)科(ke)(ke)(ke)的蜥鳥(niao)盜龍(long)(long)(long)(long)(long)(long)、及(ji)艾伯塔龍(long)(long)(long)(long)(long)(long)亞(ya)科(ke)(ke)(ke)。恐龍(long)(long)(long)(long)(long)(long)公(gong)園組(zu)及(ji)雙麥迪遜組(zu)有(you)著類(lei)似奧爾德(de)曼組(zu)的動物群組(zu)成(cheng),而恐龍(long)(long)(long)(long)(long)(long)公(gong)園組(zu)則沒有(you)互(hu)相競(jing)爭的多種大型獵食恐龍(long)(long)(long)(long)(long)(long)。蛇發女(nv)怪(guai)龍(long)(long)(long)(long)(long)(long)與達斯布雷龍(long)(long)(long)(long)(long)(long)同(tong)時生(sheng)活(huo)于(yu)恐龍(long)(long)(long)(long)(long)(long)公(gong)園組(zu)與雙麥迪遜組(zu)上層(ceng)。幼年暴龍(long)(long)(long)(long)(long)(long)科(ke)(ke)(ke)的生(sheng)態(tai)位,介乎成(cheng)年暴龍(long)(long)(long)(long)(long)(long)科(ke)(ke)(ke)及(ji)小型的獸腳亞(ya)目(mu)之間,它們之間的體重有(you)數(shu)倍的差距(ju)。