ORDER AGNOSTIDA
http://www.trilobites.info/agnostidaguide.gif Introduction: Small trilobites (usually only a few mm long) with cephalon and pygidium strongly similar in outline and size (isopygous); enrollment typical.Cephalon: cephalic shield with deeply parabolic outline, maximum width usually anterior of genal angle, sutures proparian or lacking; border convex; glabella fusiform, widest at base (except in Condylopygidae), glabellar segmentation highly variable, sometimes complex, but in some species entirely effaced; most species eyeless; hypostome natant, sometimes specialized with ribbon-like wings; rostral plate lacking (or uncalcified).
Thorax: segments 2 (Agnostina) or 3 (some Eodiscina), axis typically broad, short fulcrate pleurae.
Pygidium: strongly isopygous; pygidial margin typically closely matching cephalic margin.
Occurrence: L. Cambrian to U. Ordovician (Ashgill). 大概意思 利用电子字典翻译的
简介:小三叶虫(通常仅几毫米),pygidium强烈类似- isopygous大纲和尺寸();招生的典型。
侧护盾和深-:抛物面轮廓,最大宽度的角度,genal通常前proparian缝合或缺乏;边界glabella梭形、宽凸;在基地(除了Condylopygidae),glabellar分段高度可变的,有时是复杂的,但在某些物种完全抹去,大部分物种目盲,hypostome游泳,有时专业和带状翅膀;缺乏(或uncalcified时板)。
胸段(2):Agnostina)或三(有些Eodiscina)、轴、短fulcrate pleurae通常广泛。
isopygous;pygidial Pygidium:强烈侧缘紧密匹配的典型。
对美国发生:l寒奥陶系(Ashgill)。 AGNOSTIDA includes two Suborders:
Agnostina
http://www.trilobites.info/agnostina.gif and Eodiscina
http://www.trilobites.info/eodiscina.gif
意思是 AGNOSTIDA包括两目。１Agnostina ２Eodiscina 现在给大家介绍他的２个目首先是Suborder Agnostina http://www.trilobites.info/agnostinaguide.gif
Suborder Agnostina
Cephalon: no facial sutures or eyes; cephalothoracic aperture present.
Thorax: 2 thoracic segments bearing distinctive articulating structures, but no articulating half-ring on anterior thoracic segment.
Pygidium: axis usually wide, inflated, 3 or fewer segments, one of which usually carries a tubercle; pygidial margin often bearing posterolateral spines. Cuticle thin.
Superfamilies: Agnostoidea and Condylopygoidea. Superfamily Agnostoidea
Cephalon: with basal glabella lobes anteriorly directed, no clear occipital structure present, anterior glabellar lobe typically subequal in width to posteroglabella, or narrowing forward (not laterally expanded).
Thorax: as in typical Agnostina.
Pygidium: variable within bounds of typical Agnostina.
Suborder Agnostina
没有面部缝合-或眼睛,cephalothoracic光圈的礼物。
胸部:2胸段结构独特,但现实的轴承,没有现实的half-ring胸段前。
Pygidium:轴、夸张,通常宽3个或更少的片段,一个带有一个tubercle;pygidial保证金经常轴承后外侧刺。皮薄。
Superfamilies:Agnostoidea和Condylopygoidea。
摘要Agnostoidea
glabella -基底:没有明确的指示,前方叶枕结构、前glabellar叶宽度subequal典型的posteroglabella,或缩小前锋(不是侧向扩张)。
在典型的Agnostina胸腔。 http://www.trilobites.info/galagnptychagnostus.jpg http://www.trilobites.info/Agnostus_pisiformis_vent_sm.jpg http://www.trilobites.info/importD2.jpg http://www.trilobites.info/ordagn2007.jpg 现在是Suborder Eodiscina http://www.trilobites.info/eodiscinaguide.gif Below are some representative Eodiscina:（意思是：下面是一些有代表性的Eodiscina）
Pagetia
Eodiscidae
http://www.trilobites.info/eodiscina.gifTsunyidiscus
Tsunyidiscidae
http://www.trilobites.info/agnostida.gifSerrodiscus
Weymouthiidae
http://www.trilobites.info/Serrodiscus.gif
Suborder Eodiscina
简介:有争议的Eodiscina放置在Agnostida。在场的眼睛,缝合,典型胸结构表明Eodiscina显然是三叶虫(或者类似于Ptychopariida),整体相似,在Agnostida Agnostina(1997年)中普遍存在的系统处理当前的论述。
proparian缝合-:当;有些保留的眼睛;glabella通常简单,可以缩小和塔楼。
胸部:2 / 3的正常胸段表达形式half-rings牙
Pygidium:轴可狭长,靠近边缘,一般截然分为超过3 ringlike区段;在某些物种的胸腔区域划分,有时pygidial分割抹你浇透地的犁沟,边境经常很深,有时spin-bearing轴。
英文 Suborder Eodiscina
Introduction: There is some controversy over the placement of Eodiscina in the Agnostida. Presence of eyes, sutures, and typical thoracic structure suggest that Eodiscina are clearly trilobites (perhaps akin to Ptychopariida), and the overall similarity to Agnostina (and placement in Agnostida) prevails in the 1997 systematic treatment of the current Treatise.
Cephalon: with proparian sutures, when present; some retain eyes; glabella usually simple, may be narrow and tapering.
Thorax: 2 or 3 thoracic segments of normal trilobite form, with articulating half-rings
Pygidium: axis can be long and narrow, extending close to margin, generally distinctly divided into more than 3 ringlike segments; pleural region segmented in some species, sometimes pygidial segmentation effaced; border furrows often very deep; axis sometimes spin-bearing.
页:
[1]
2