說(shuō)明1：后面很多事情要處理，發(fā)布頻率不會(huì)那么高了。之前寫(xiě)的幾篇半成品由于要寫(xiě)完需要耗費(fèi)大量時(shí)間精力，就先存為草稿等日后有空再說(shuō)了。

說(shuō)明2：翻譯中有些是用自己的話說(shuō)的，自己辨別。

說(shuō)明3：初識(shí)縫合線的話請(qǐng)先看：https://zhuanlan.zhihu.com/p/84813950，此篇對(duì)初識(shí)者的作用不大。

很多人喜歡說(shuō)縫合線（suture line），用縫合線，但縫合線實(shí)際上指氣室隔壁與外殼相接處形成的紋路。而在很多情況下說(shuō)的縫合線實(shí)際上應(yīng)該是隔壁/隔板（septa）。同時(shí)，縫合線不只是菊石中存在，腹足類中那些接觸線也是縫合線，有孔蟲(chóng)那些也是。(septa是septum的復(fù)數(shù)形式，下面不會(huì)特意區(qū)分了）

菊石隔板和縫合線對(duì)古生物學(xué)家們來(lái)說(shuō)有著巨大的吸引力，很多研究者對(duì)菊石隔板和其皺狀邊緣的功能進(jìn)行深入的研究。Westermann(1971, 1999)[1][2]、Kennedy和Cobban(1976)[3]、Hewitt和Westermann(1997, 2003)[4][5]以及Keupp(2000)[6]對(duì)所有可用的假說(shuō)進(jìn)行了概述。在此簡(jiǎn)要地重復(fù)這些，以闡明菊石復(fù)雜的隔板和僅局限于Lytoceratoidea的隔葉（septal lobe）的可能功能。

下面從生理（1-7）和機(jī)械性能（8-12）兩個(gè)方面對(duì)其功能進(jìn)行解釋和簡(jiǎn)要討論：

[1] Westermann GEG (1971) Form, structure and function of shell and siphuncle in coiled Mesozoic ammonoids. Life sciences contributions. R Ont Mus 78:1–39

[2] Westermann GEG (1999) Recent hypotheses on mechanical and metabolic functions of septal fluting and sutural complexity in post-carboniferous ammonoids. Ber Geol Bundesanst 46:120

[3]?Kennedy WJ, Cobban WA (1976) Aspects of ammonite biology, biogeography, and biostratigraphy. Spec Pap Palaeontol 17:1–94

[4]?Hewitt RA, Westermann GEG (1997) Mechanical significance of ammonoid septa with complex sutures. Lethaia 30:205–212

[5]?Hewitt RA, Westermann GEG (2003) Recurrences of hypotheses about ammonites and Argonauta. J Paleontol 77:792–795

[6]?Keupp H (2000) Ammoniten. pal?obiologische Erfolgsspiralen. Thorbecke, Stuttgart

1. 復(fù)雜性和代謝率

隔板的形態(tài)反映了外套膜后方的形狀，Newell（1949）[7]?認(rèn)為其彎折有助于更好地呼吸，Pia（1923）[8]?認(rèn)為是為了更好地產(chǎn)氣。因此，縫合線的復(fù)雜程度應(yīng)該與菊石代謝有關(guān)。代謝率通常被估計(jì)為耗氧率，但也可以被認(rèn)為是浮力控制率或生物礦化率。縫合線復(fù)雜性反映代謝率的假設(shè)可以被以下事實(shí)所證偽:(i)隔壁的折疊方式遠(yuǎn)不能最理想地增加最大呼吸表面的表面積(如Hammer和Bucher 1999年所證明的那樣[9]，它是最小面積的表面)，(ii)隔壁外套膜可能不直接接觸海水，所有頭足類動(dòng)物都發(fā)育出鰓來(lái)呼吸;(iii)腔室的氣體填充是通過(guò)體管提供的(Tanabe et al. 2015)[10]。

[7]?Newell ND (1949) Phyletic size increase, an important trend illustrated by fossil invertebrates. Evolution 3:103–124

[8]?Pia J (1923) über die ethologische Bedeutung einiger Hauptzüge in der Stammesgeschichte der Cephalopoden. Ann Nat Mus Wien 36:50–73

[9] Hammer ?, Bucher H (1999) Reaction-diffusion processes: application to the morphogenesis of ammonoid ornamentation. Geobios 32:841–852

[10] Tanabe K, Sasaki T, Mapes RH (2015) Soft-part anatomy of the siphuncle in ammonoids.

2. 快速控制浮力

曲折的隔壁增加了腔室中的可濕性殼基質(zhì)表層(薄膜)，以支持更快地將液體輸送到體管從而控制浮力(Mutvei 1967)[11];這一解釋得到了Bayer?[12]?對(duì)有機(jī)intracameral（內(nèi)氣室？）膜的發(fā)現(xiàn)(1975;另見(jiàn)2012，Seuss等人[13]和2015，Polizotto等人[14])和cameral膜的存在(Weitschat和Bandel 1991[15];Polizotto et al. 2015[16])的支持，但與之相矛盾的是:(i)隔壁面積最大化的非最佳結(jié)構(gòu)；(ii)folioles（次級(jí)鞍）和lobules（次級(jí)葉）的低角度，可能阻礙(但加速)完全排空。然而，這一假設(shè)不能被完全否定，但它似乎不足以作為縫合復(fù)雜性進(jìn)化的唯一解釋。

[11] Mutvei H (1967) On the microscopic shell structure in some Jurassic ammonoids. Neues Jahrb Geol Pal?ontol Abh 129:157–166

[12]?Bayer U (1975) Organische Tapeten im Ammoniten-Phragmokon und ihr Einflu? auf die Fossilisation. Neues Jahrb Geol Pal?ontol, Monatshefte 1975(1):12–25

[13]?Seuss B, Mapes RH, Klug C, Nützel A (2012) Exceptional cameral deposits in a sublethally injured carboniferous orthoconic nautiloid from the Buckhorn Asphalt Lagerst?tte in Oklahoma, USA. Acta Palaeontol Pol 57:375–390

[14] Polizzotto K, Landman NH, Klug C (2015) Cameral membranes, pseudosutures, and other soft tissue imprints in ammonoid shell.?

[15] Weitschat W, Bandel K (1991) Organic components in phragmocones of boreal Triassic ammonoids: implications for ammonoid biology. Pal?ontol Z 65:269–303

[16] Polizzotto K, Landman NH, Klug C (2015) Cameral membranes, pseudosutures, and other soft tissue imprints in ammonoid shell.?

3. 改善浮力調(diào)節(jié)能力

波紋形的凹槽使cameral液體可以通過(guò)表面張力儲(chǔ)存，以改善浮力調(diào)節(jié)(Kulicki 1979[17];Kulicki和Mutvei,1988[18];Weitschat和Bandel,1991[19];Saunders,1995[20]);毫無(wú)疑問(wèn)，表面張力將保持剩余的腔內(nèi)液體，因此腔內(nèi)水的橫向移動(dòng)將被最小化。

[17] Kulicki C (1979) The ammonite shell, its structure, development and biological significance. Palaeontol Pol 39:97–142

[18]?Kulicki C, Mutvei H (1988) Functional interpretation of ammonoids septa. In: Wiedmann J, Kullmann J (eds) Cephalopods-present and past. Schweitzerbart, Stuttgart

[19]?Weitschat W, Bandel K (1991) Organic components in phragmocones of boreal Triassic ammonoids: implications for ammonoid biology. Pal?ontol Z 65:269–303

[20]?Saunders WB (1995) The ammonoid suture problem: relationships between shell and septum thickness and suture complexity in Paleozoic ammonoids. Paleobiology 21:343–355

4. 改變浮力

笛卡兒潛水者模型（Cartesian Diver Model）(Seilacher and Labarbera 1995[21];Seilacher & Gishlick 2015[22])假設(shè)最后一個(gè)隔壁保持未鈣化直到下一個(gè)腔室周期開(kāi)始;在這段時(shí)間里，隔壁外套膜后面的空間可能充滿了氣體，起著像魚(yú)鰾一樣的作用。封閉氣體的體積可以通過(guò)橫跨隔膜的縫合肌肉來(lái)調(diào)節(jié)，以改變浮力。這將允許菊石在水層中垂直移動(dòng)，而不需要消耗大量的能量;雖然這是一個(gè)令人興奮的假設(shè)，但它缺乏支撐(Jacobs 1996[23])，甚至可能與Seilacher的結(jié)合點(diǎn)模型（Tie-Point Model）相矛盾:假設(shè)lobule的形成是由肌肉的附著控制的，鞍的形成是由柔軟的身體向前方向的拉動(dòng)而簡(jiǎn)單地形成的，隔套（septal mantle）的可收縮纖維的附著將不是收縮或擴(kuò)張充滿氣體的隔壁前空間的最佳選擇;如果連接在縫合處的肌肉在相反的方向上發(fā)揮作用，則可以預(yù)期lobules和folioles的形狀相似。在任何情況下，從近代的鸚鵡螺中了解到氣殼的功能，并不是一個(gè)質(zhì)量差的假設(shè)。

[21] Seilacher A, Labarbera M (1995) Ammonites as Cartesian Divers. Palaios 10:493–506

[22]?Seilacher A, Gishlick AD (2015) Morphodynamics. CRC Press, London

[23]?Jacobs DK (1996) Chambered cephalopod shells, buoyancy, structure and decoupling: history and red herrings. Palaios 11:610–614

5. 肌肉附著

一些人認(rèn)為，隔壁凹陷促進(jìn)了主要內(nèi)收肌的附著(Seilacher 1975[23], 1988[24];Henderson，1984[25];Ebel，1992[26]);多組菊石的主要肌肉系統(tǒng)已被描述，且它們位于隔壁的前面(Doguzhaeva和Mutvei 1991[27],1996[28];Richter，2002[29];Klug et al.，2008[30];Richter和Fischer，2002[31])。因此，隔壁凹陷明顯不用于插入頭部牽縮肌或漏斗牽縮肌。

[23] Seilacher A (1975) Mechanische simulation und funktionelle evolution des Ammoniten-Septums. Pal?ontol Z 49:268–286

[24] Seilacher A (1988) Why are nautiloid and ammonite sutures so different? Neues Jahrb Geol Pal?ontol Abh 177:41–69

[25] Henderson RA (1984) A muscle attachment proposal for septal function in Mesozoic ammonites. Palaeontology 27:461–486

[26] Ebel K (1992) Mode of life and soft body shape of heteromorph ammonites. Lethaia 25:179–193

[27] Doguzhaeva LA, Mutvei H (1991) Organization of the soft-body in Aconeceras (Ammonitina), interpreted on the basis of shell-morphology and muscle-scars. Palaeontol A 218:17–33

[28] Doguzhaeva LA, Mutvei H (1996) Attachment of the body to the shell in ammonoids. In: Landman NH, Tanabe K, Davis R (eds) Ammonoid paleobiology. Plenum, New York

[29] Richter U (2002) Gewebeansatz-Strukturen auf Steinkernen von Ammonoideen. Geol Beitr Hann 4:1–113

[30] Klug C, Meyer E, Richter U, Korn D (2008) Soft-tissue imprints in fossil and recent cephalopod septa and septum formation. Lethaia 41:477–492

[31] Richter U, Fischer R (2002) Soft tissue attachment structures on pyritized internal moulds of ammonoids. Abh Geol Bundesanst 57:139–149

6. 助于排空腔室

隔壁有助于在幾乎任何深度排空腔室(Ward 1987[32]);這似乎是現(xiàn)實(shí)的原因，因?yàn)楝F(xiàn)代鸚鵡螺是這樣使用腔室的。只有各種菊石分類群的內(nèi)爆深度（implosion depths ）限制了這一點(diǎn)。然而，鸚鵡螺的隔壁只是輕輕彎折，因此，這種比較有點(diǎn)存疑。

[32] Ward PD (1987) The natural history of Nautilus. Allen and Unwin, Boston

7. 改善浮力逃避捕食或彌補(bǔ)殼的損傷

彎折的隔壁改善浮力控制，以逃避捕食(Daniel et al. 1997[33])，并有助于快速充滿再生菊石殼室，以彌補(bǔ)殼的損失(Kr?ger 2001[34], 2002[35]);如果與現(xiàn)代鸚鵡螺的氣殼功能(Ward 1979[36],1987[37])的實(shí)際比較是正確的，那么腔室排空是通過(guò)滲透實(shí)現(xiàn)的，因此可能太慢，無(wú)法幫助它們逃脫捕食者。為了在受到持續(xù)改變浮力的損傷后重新獲得浮力控制能力，再次灌滿（reflooding）可能已經(jīng)足夠快了。但是，這足以解釋復(fù)雜性不斷增加的強(qiáng)烈進(jìn)化趨勢(shì)嗎?

[33] Daniel TL, Helmuth BS, Saunders WB, Ward PD (1997) Septal complexity in ammonoid cephalopods increased mechanical risk and limited depth. Paleobiology 23:470–481

[34] Kr?ger B (2001) Discussion—comments on Ebel’s benthic-crawler hypothesis for ammonoids and extinct nautiloids. Pal?ontol Z 75:123–125?

[35] Kr?ger B (2002) On the efficiency of the buoyancy apparatus in ammonoids: evidences from sublethal shell injuries. Lethaia 35:61–70

[36] Ward PD (1979) Cameral liquid in Nautilus and ammonites. Paleobiology 5:40–49

[37] Ward PD (1987) The natural history of Nautilus. Allen and Unwin, Boston

8. 軟組織附著

隔壁幫助將柔軟的身體連接到外殼上(von Buch,1829[38],1830[39];Suess,1865[40];Tate and Blake，1876[41];Steinmann，1888[42]，1925[43];Diener，1912[44];Spath,1919[45];Reyment 1955[46];Hengsbach，1978[47];Henderson，1984[48]);縫合線當(dāng)然是一個(gè)臨時(shí)的軟組織附著部位，定期溶解發(fā)生轉(zhuǎn)移(Klug et al. 2008[49])，但這種連接很可能不是很強(qiáng)。

[38] Buch Lv (1829) Note sur les ammonites. Annales des sciences naturelles par Audouin. Ad Brogniart et Dumas 17:267–275

[39] Buch Lv (1830) Note über Ammoniten. Jahrb Miner, Geognosie. Geol Petrefaktenk 1:397–398

[40] Suess E (1865) über Ammoniten. Sitzungsber Math-Naturw Kl Kaiserl Akad Wissensch, Abt 1(52):71–89

[41] Tate R, Blake JF (1876) The Yorkshire lias. J. Van Vorst, London

[42] Steinmann G (1888) Vorl?ufige Mittheilung über die Organisation der Ammoniten. Ber Naturf Ges Freibg Breisgau 4:113–129

[43] Steinmann G (1925) Beitr?ge zur Stammesgeschichte der Cephalopoden I. Argonauta und die Ammoniten. Z Indukt Abstamm- Vererb 36:350–416

[44] Diener C (1912) Lebensweise und Verbreitung der Ammoniten. Neues Jahrb Min Geol Pal?ontol 192:67–89

[45] Spath LF (1919) Notes on Ammonites. Geol Mag 56:27–35

[46] Reyment RA (1955) Some examples of homeomorphy in Nigerian Cretaceous ammonites. Geologisca Foren i Stockh Forh 77:567–594

[47] Hengsbach R (1978) Zur Sutur-Asymmetrie bei Anahoplites (Ammonoidea; Kreide). Senck leth 59:377–385

[48] Henderson RA (1984) A muscle attachment proposal for septal function in Mesozoic ammonites. Palaeontology 27:461–486

[49] Klug C, Meyer E, Richter U, Korn D (2008) Soft-tissue imprints in fossil and recent cephalopod septa and septum formation. Lethaia 41:477–492

9. 抵抗水壓

凹槽加強(qiáng)了殼壁和最后形成的隔壁以抵抗靜水壓力(Buckland，1836[50]，他也接受了von Buch的想法;Owen，1843[51];Tate ? and Blake，1876[52];Zittel 1884[53];Pfaff，1911[54];Nagao and Saito，1934[55];Reyment 1955[56];Westermann，1958[57],1971[58],1975[59];Seilacher 1975[60];Kennedy and Cobban，1976[61];Hewitt and Westermann，1997[62];Hassan等，2002[63];de Blasio，2008[64]);Jacobs(1990,1992,1996[65,66,67])回顧了所謂的“Buckland假說(shuō)”。盡管隔膜褶邊在增強(qiáng)耐壓能力方面存在一定的功能限制，但在部分充滿氣體的氣殼中存在這種壁很可能提供了一些流體靜力支持，這反映在縫合線類似物（sutural approximation，這個(gè)沒(méi)搞懂是啥）和殼體曲率之間的相關(guān)性中(Buckland 1836[50];Jacobs，1990[65],1996[67];contra Saunders 1995[20])。相比之下，褶邊本身可能對(duì)這一功能貢獻(xiàn)不大，并被認(rèn)為與測(cè)深無(wú)關(guān)，和/或陸表海菊石和海洋菊石的棲息地深度沒(méi)有重大差異(Olóriz和Palmqvist 1995[68];Olóriz等，1997[69],1999[70];Perez-Claros 2005[71])。然而，在先前列出的論文中，隔壁厚度沒(méi)有被考慮在內(nèi)。De Blasio(2008)[64]描述了縫合線褶皺的相關(guān)功能，即加固由于靜水壓力引起的殼體收縮，這可能決定浮力的損失。

[50] Buckland W (1836) Geology and mineralogy considered with reference to natural theology. Treatise VI. The bridgewater treatise on the power, wisdom, and goodness of god as manifested in the Creation. W. Pickering, London

[51] Owen R (1843) Lectures on the comparative anatomy and physiology of the invertebrate animals. p 392

[52] Tate R, Blake JF (1876) The Yorkshire lias. J. Van Vorst, London

[53] Zittel KA (1884) Cephalopoda. In: Zittel KA (ed) Handbuch der Palaeontologie. 1. Abth, 2. Band. R. Oldenbourg, Munich

[54] Pfaff E (1911) über Form und Bau der Ammonitensepten und ihre Beziehungen zur Suturlinie. Jahrb Nieders?chs Geol Ver (Geol Abt Nat Ges Hann) 4:207–223

[55] Nagao T, Saito R (1934) Peculiar septal features observed in ammonites of certain lytoceratid genera. Proc Imp Acad 10:357–360

[56] Reyment RA (1955) Some examples of homeomorphy in Nigerian Cretaceous ammonites. Geologisca Foren i Stockh Forh 77:567–59

[57] Westermann GEG (1958) The significance of septa and sutures in Jurassic ammonite systematics. Geol Mag 95:441–455

[58] Westermann GEG (1971) Form, structure and function of shell and siphuncle in coiled Mesozoic ammonoids. Life sciences contributions. R Ont Mus 78:1–39?

[59] Westermann GEG (1975) Model for origin, function and fabrication of fluted cephalopod septa. Pal?ontol Z 49:235–253

[60] Seilacher A (1975) Mechanische simulation und funktionelle evolution des Ammoniten-Septums. Pal?ontol Z 49:268–286

[61] Kennedy WJ, Cobban WA (1976) Aspects of ammonite biology, biogeography, and biostratigraphy. Spec Pap Palaeontol 17:1–94????

[62] Hewitt RA, Westermann GEG (1997) Mechanical significance of ammonoid septa with complex sutures. Lethaia 30:205–212

[63] Hassan MA, Westermann GEG, Hewitt RA, Dokainish MA (2002) Finite element analysis of simulated ammonoid septa (extinct Cephalopoda): septal and sutural complexities do not reduce strength. Paleobiology 28:113–126

[64] De Blasio FV (2008) The role of suture complexity in diminishing strain and stress in ammonoid phragmocones. Lethaia 41:15–24

[65] Jacobs DK (1990) Sutural pattern and shell stress in Baculites with implications for other cephalopod shell morphologies. Paleobiology 16:336–348?

[66]Jacobs DK (1992) The support of hydrostatic load in cephalopod shells—adaptive and ontogenetic explanations of shell form and evolution from Hooke 1695 to the present. Evol Biol 26:287–349?

[67] Jacobs DK (1996) Chambered cephalopod shells, buoyancy, structure and decoupling: history and red herrings. Palaios 11:610–614

[68] Olóriz F, Palmqvist P (1995) Sutural complexity and bathymetry in ammonites: fact or artifact? Lethaia 28:167–170

[69] Olóriz F, Palmqvist P, Pérez-Claros JA (1997) Shell features, main colonized environments, and fractal analysis of sutures in Late Jurassic ammonites. Lethaia 30:191–204?

[70] Olóriz F, Palmqvist P, Pérez-Claros JA (1999) Recent advances in morphometric approaches to covariation of shell features and the complexity of suture lines in Late Jurassic ammonites, with reference to the major environments colonized. In: Olóriz F, Rodríguez-Tovar FJ (eds) Advancing research on living and fossil cephalopods. Kluwer Academic, New York

[71] Pérez-Claros JA (2005) Allometric and fractal exponents indicate a connection between metabolism and complex septa in ammonites. Paleobiology 31:221–232

10. 承受軟體施加的壓力

褶邊(Frilling)幫助最后的隔壁承受通過(guò)軟體施加到殼壁上的壓力(Pfaff 1911[54]);這一假設(shè)可能有一定的真實(shí)性，因?yàn)樾滦纬傻母舯诘姆堑V化或不完全礦化膜可能更緊密地保留在褶皺縫合線中，從而允許更大的壓力梯度在氣殼和柔軟部分之間建立(Klug et al. 2008[49])。

11. 增加總重以控制浮力

隔壁增加了殼體的整體重量以控制浮力(Reyment 1958[72];Teichert 1967[73]);毫無(wú)疑問(wèn)，隔層增加了重量，但據(jù)推測(cè)，這不是隔壁的主要功能，因?yàn)轭~外的壓載物可以通過(guò)簡(jiǎn)單地增加其他地方的外殼厚度來(lái)增加。此外，當(dāng)?shù)兔芏惹惑w填料也被考慮在內(nèi)時(shí)，這個(gè)概念就顯得不太合理了。

[72] Reyment RA (1958) Some factors in the distribution of fossil Cephalopods. Acta Universitatis Stockholmiensis—Stockholm contributions. Geology 1:97–184

[73] Teichert C (1967) Major features of cephalopod evolution. Essays in paleontology and stratigraphy. Spec Pub 2:162–210

12. 身體與殼體連接

Lewy(2002,2003[74、75])認(rèn)為，復(fù)雜的凹槽間隔是軟體和殼體之間更強(qiáng)連接的結(jié)果(臨時(shí)保持系統(tǒng)，沒(méi)有肌肉附著)。這導(dǎo)致Lewy(2002)[74]假設(shè)，隔壁邊緣凹槽的復(fù)雜性越大，菊石就越能承受身體和漂浮著的殼體之間的牽引力，因此，菊石捕食和與其他生物競(jìng)爭(zhēng)就更有侵略性;這一假設(shè)完全缺乏來(lái)自軟組織或肌肉印記的證據(jù)(Doguzhaeva和Mapes 2015[76];Klug and Lehmann 2015[77])。

[74] Lewy Z (2002) The function of the ammonite fluted septal margins. J Paleontol 76:63–69 [75] Lewy Z (2003) Reply to Checa and to Hewitt and Westermann. J Paleontol 77:796–798

[76] Doguzhaeva LA, Mapes RH (2015) Muscle scars in ammonoid shells.

[77] Klug C, Lehmann J (2015) Soft part anatomy of ammonoids: reconstructing the animal based on exceptionally preserved specimens and actualistic comparisons.

假縫合線 & 拖線/拖帶 & 體管膜

內(nèi)容很多，暫且不提，僅放圖于此。