Ceratopsia

Ceratopsia thrived in North America and Asia during the Cretaceous Period (about 146 to 65.5 million years ago). Their name means "horned face" and indeed many of them did feature bony horns projecting from their skulls. ■
  • (A) The horns may look quite predatory, but Ceratopsians were herbivores1, so their horns were defensive in nature and may have been used to enforce order in the group. ■
  • (B) Not all Ceratopsians had horns, but all had beaklike mouths. ■
  • (C) The fossil record has revealed three distinct families among Ceratopsia: Psittacosaurids, Protoceratopsids, and Ceratopsids. Triceratops, a member of the Ceratopsid family, is probably the best known species of Ceratopsia. With its facial horns and neck display, it exhibits many of the features commonly associated with this dinosaur group. ■
  • (D) However, there are species of Ceratopsia that are quite different from the familiar Triceratops.
    The Psittacosaurids comprise the Psittacosaurus genus2 and the Hongshanosaurus genus. Although not much fossil data are available for Hongshanosaurus, comparisons with Psittacosaurus can be made. Evidence indicates that both were roughly deer-sized bipeds dwelling in East Asia. Hongshanosaurus had beak points on both upper and lower jaws, while only the upper jaw of Psittacosaurus was pointed. Much more fossil evidence is available for Psittacosaurus species. At least one species had long quills along its back and tail. Researchers speculate these quills were used for display during mating or fighting. As early Ceratopsians, the Psittacosaurids had many anatomical features that would show up in similar or interestingly modified forms in later species, but none of the Psittacosaurids had the neck frills or facial horns that came to be associated with the Ceratopsians.
    Although their name suggests that the Protoceratopsids were the first of this dinosaur group to have horned faces, they, in fact, lacked the well-developed horns of later species. While they more closely resembled the Ceratopsids on the whole, they were still relatively small and hornless. Protoceratops, a six-foot-long quadrupedal herbivore, is a representative Protoceratopsid. Fossil examples found in China and Mongolia show that it had a turtle-like beak and a neck frill, a version of which would show up among the more familiar Ceratopsids. While Protoceratops did have some knobby points on its skull, the points only slightly hinted at the impressive horns that appeared on the Ceratopsids.
    With the arrival of Triceratops and other advanced Ceratopsids, Ceratopsia reached new levels of sophistication, variety, and size. All Ceratopsid fossils have been found in western North America and reveal that they were quadrupedal herbivores with beaked jaw tips and rows of teeth specialized for shearing. The family featured a remarkable array of horns, neck frills, and spines. These neck frills, manifesting in various shapes and sizes, probably were too thin to be practical as a defense against predator species, and researchers speculate that they were used during mating displays, for anchoring jaw muscles, for regulating body temperature, or for a combination of these purposes. Most Ceratopsids had two long brow horns and a short horn on the nasal ridge. Because the Ceratopsids were vegetarian and fairly large (up to 30 feet long and 10 feet tall), researchers think that the horns, along with the neck frills, largely served functions of competition, whether in displays or combat. Moreover, since intraspecific conflicts often are tests of strength rather than fights to the death, thin neck frills may have been sturdy enough to provide some protection during such confrontations.
    There is evidence of Ceratopsian species that do not neatly fall into the familial categories as described. While these species appear closely related to Ceratopsia, they tend to be smaller and more primitive. Researchers have debated over recognizing a distinctly new Ceratopsian family or grouping these misfit species with an existing family. Psittacosaurids, Protoceratopsids, and Ceratopsids are the commonly accepted Ceratopsian families with established member species and defined characteristics. Despite some controversies over minor species, a view of the Ceratopsian families is a view of fascinating adaptations and development in a unique dinosaur group.


单选题 According to paragraph 1, why were Ceratopsians' horns probably not used for hunting?
【正确答案】 B
【答案解析】[解析] 细节题 原文中没有直接说明角龙类不用犄角捕食猎物的原因，但是第一段提到角龙类因为有犄角而被误认为是食肉动物，但是实际上是食草动物。也就是说角龙类并不是利用犄角来捕食猎物的食肉动物，因此正确答案应该是B项。A项虽然是文章中提到的内容，但与问题无关。C项和D项的内容没有在文章中出现。
单选题 The word "comprise" in the passage is closest in meaning to
【正确答案】 A
【答案解析】[解析] 词汇题 comprise的意思是“包括；由……构成”，因此，include的意思与其最接近。
单选题 According to paragraph 2, an example of Psittacosaurus featured
【正确答案】 B
【答案解析】[解析] 细节题 第二段对鹦鹉嘴龙科中的鹦鹉嘴龙和红山龙进行了比较，提到了鹦鹉嘴龙的两个特征。与红山龙不同的是鹦鹉嘴龙又有上腭突出。至少有一种鹦鹉嘴龙在背部和尾部长有很长的翎毛。A项讲的是红山龙的特征。
单选题 It may be inferred from the passage that Protoceratopsid means
【正确答案】 D
【答案解析】[解析] 推理题 第三段提到了原角龙科的特征。第一句话就提到它们的名字暗示了它们是最早的面部长角的恐龙。A项指的是鹦鹉嘴龙科，B项和C项没有在文章中出现。
单选题 The word "it" in the passage refers to
【正确答案】 A
【答案解析】[解析] 指代关系题 指示代名词所指代的名词一般出现在指示代名词所属的句子中或者其前面的句子中。本文中指示代名词所属的句子里没有可以替换it的名词，所以要在前面的句子中找。前面的句子是“Protoceratops, a six-foot-long quadrupedal herbivore, is a representative Protoceratopsid.” it指代的是protoceratops还是protoceratopsid呢?一般情况下指示代名词用作主语时，指代其前一句的主语，因此答案是A项。
单选题 Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect answer choices change the meaning in important ways or leave out essential information.
【正确答案】 C
【答案解析】[解析] 句子转换题 首先要注意only slightly(仅仅略微地)的词义再判断句子的意思。阴影部分的意思可理解为：原角龙头上确实有个突起，但若是和后来出现的角龙的大犄角相比算不了什么。因此C项是正确答案。
单选题 The word "array" in the passage is closest in meaning to
【正确答案】 A
【答案解析】[解析] 词汇题 array虽然有“排列”的意思，在此句中的意思应为“大量；大堆”。
单选题 All of the following are mentioned in paragraph 4 as characteristics of Ceratopsids EXCEPT
【正确答案】 B
【答案解析】[解析] 错误信息题 第四段提到了有关高度进化的角龙的相关信息。A，C，D三项都是文章中提到的内容，因此B项是正确答案。这一段的中间提到大部分的角龙的额头上有两个长犄角，鼻梁上有一个短犄角(Most Ceratopsids had two long brow horns and a short horn on the nasal ridge.)。
单选题 In paragraph 5, the author mentions species that do not fit into the described families in order to
【正确答案】 C
【答案解析】[解析] 判断意图题 这是判断作者意图的问题。第五段提到一些角龙类没有划分到现有的角龙科。本段阐述了科学家们对于如何将这些物种归类的不同意见。作者没有指出现有分类体系不完整。因此，A项是错误答案。而且文章指出不是主要物种(significant)而是少数物种(minor)存在这个问题，文章也没有呼吁对这些物种给予足够的重视，因此B项是错误答案。作者指出之前的分类方式没有将所有的角龙种类包含在内。因此C项是正确答案。
单选题 The word "controversies" in the passage is closest in meaning to
【正确答案】 B
【答案解析】[解析] 词汇题 controversy的意思是“争论；争议”。选项中只有disagreement的意思最接近。
单选题 Look at the four squares [■] that indicate where the following sentence can be added to the passage.
The Ceratopsians shared many features, but certain traits differentiate some species from others.
Where would the sentence best fit?
【正确答案】 C
【答案解析】[解析] 句子插入题 插入的句子中说“物种和物种之间也有相互区别的特征”，可以推断此句后面应是有关区分不同物种的内容。本段里第三个黑方框后面的句子是有关角龙亚目下面划分的三个科，因此应该将句子插入第三个黑方框内。
问答题 Directions: Complete the table below by matching five of the six answer choices with the Ceratopsian family that they describe. This question is worth 3 points.
【正确答案】
[*]
【答案解析】[解析] 信息归类题 原文中第二段对鹦鹉嘴龙科，第四段对角龙进行了详细的说明。我们来依次分析一下选项。
1．此句在第二段有关鹦鹉嘴龙科的内容里出现过。(…both were roughly deer-sized bipeds dwelling in East Asia.)
2．此句在第四段有关角龙的说明里出现过。(All Ceratopsid fossils have been found in western North America…)
3．在第三段提到过面部长角的最早的角龙是原角龙，因此既不属于鹦鹉嘴龙又不属于角龙的特征。
4．在第二段里出现了有关属于鹦鹉嘴龙科的鹦鹉嘴龙和红山龙的嘴的外貌特征。(Hongshanosaurus had beak points on both upper and lower jaws, while only the upper jaw of Psittacosaurus was pointed.)
5．此内容在第二段里有关鹦鹉嘴龙科的说明中提到过。(…none of the Psittacosaurids had the neck frills or facial horns…)
6．在第四段出现的有关角龙的说明与此句吻合。(Most Ceratopsids had two long brow horns and a short horn on the nasal ridge.)