【摘要】 浙江天台白垩纪地层中最常见的蛋化石类型之一是赤城山组地层(锆石U-Pb法同位素年龄约92Ma)的树枝树枝蛋(Dendroolithus dendriticus)。对比河南西峡含恐龙胚胎的蛋化石,确定其为鸭嘴龙类(Hadrosaurs)恐龙所产。鸭嘴龙类恐龙在系统分类上归鸟脚亚目(Ornithopoda Marsh,1881)鸭嘴龙超科(Hadrosauroidea Cope,1869)鸭嘴龙科(Hadrosauridae Cope,1869),建议树枝蛋化石也相应归入圆形蛋化石亚目(Spheroolithineae oosubord.nov.)树枝蛋化石超科(Dendroolithoidea oosuperfam.nov.)树枝蛋化石科(Dendroolithidae Zhao and Li1988),以便对应研究。从已知的鸭嘴龙类恐龙产蛋尺寸推算,浙江天台的树枝树枝蛋(Dendroolithus dendriticus)为身长不超过7m的恐龙所产,个体大小类似东北—蒙古发现的萨哈林日本龙(Nipponosaurus sachalinensis)、李氏黑龙江龙(Amurosaurus riabinini)和姜氏巴克龙(Bactrosaurus johnsoni)。该蛋在巢穴里,无序放置,至少3层,常超过20枚,蛋壳具韧性,重力作用下呈扁球形。更多还原

【Abstract】 Recently hundreds and thousands of fossil eggs were unearthed from the Cretaceous sequence in Tiantai Basin, Zhejiang Province, eastern China. The Dendroolithus dendriticus discovered from Upper Cretaceous Chichengshan Formation (zircon U-Pb data approximately 92Ma) was a species of the most familiar among those fossil eggs and is identified as the eggs laid by a hadrosaur based on comparisons with ones that is similar egg shell fragments and contained fossilized embryo bones from Xixia Basin, Henan Province, middle China, though any hadrosaur’s skull or skeleton has not yet been found in eastern China so far. According to the taxonomy of hadrosaur at present, their fossil eggs should be classified as follows:Suborder Ornithopoda Marsh, 1881—Spheroolithineae oosubord. nov.Superfamily Hadrosauroidea Cope, 1869—Dendroolithoidea oosuperfam. nov.Family Hadrosauridae Cope, 1869—Dendroolithidae Zhao and Li, 1988Spheroolithineae oosubord. nov.Diagnosis. -spheric or flat spheric eggs were laid optionally in a nest.Horizon. -The Triassic to CretaceousDendroolithoidea oosuperfam. nov.Diagnosis. -The eggs were flat spherical and were laid optionally in a nest. The eggshell was rough in the exterior surface and was consisted of two basic layers:outer prismatic and inner mammillary layers. Pore canals branched off mightily.Horizon. -CretaceousOofamily Dendroolithidae Zhao and Li, 1988 Diagnosis and Horizon. -As for oosuperfamily.Oogenus Dendroolithus Zhao and Li, 1988 Type oospecies Dendroolithus wangdianensis Zhao and Li, 1988 Dendroolithus dendriticus Fang et al.,1998 Diagnosis. -The eggs were flat spherical or subspherical in shape, with the diameter of 130mm~140mm and height of about 60mm. The eggshell, rough in the exterior surface and little sleek in the interior surface, was 1mm thick and consisted of two basic layers:outer prismatic and inner mammillary layers. Prisms with growth lines were various in shape and arranged wide-space, and merged together in near exterior surface of the eggshell. The mammillae and prisms were without a diagnosis of borderline between them. A mammilla was wide-rounded and the basal spherolite with radiate crystal lines. Pore canals wide and branched off mightily, and constringed in near exterior surface of the eggshell.Locality and Horizon:Suangtang, Tiantai County, Zhejiang Province. Upper Cretaceous Chichengshan FormationWhich was the hadrosaur laid the Dendroolithus dendriticus in Tiantai Basin? Of excavated known fossil hadrosaurs and doubting hadrosaurs from eastern Asia, except specimens of Tanius, Gilmoreosaurus, Microhadrosaurus, Barsboldia and Nanningosaurus et al. were too fragmentized to reconstruct their appearances, suspects may include Mandschurosaurus, Nipponosaurus, Amurosaurus, Charonosaurus, Olorotitan, Bactrosaurus, Shantungosaurus, Tsintaosaurus and Zhuchengosaurus et al. According to known sizes of fossilized skeleton and eggs of Hypacrosaurus stebingeri and Maiasaura peeblesorum from North America, the length of a hadrosaur laid Dendroolithus dendriticus in Tiantai Basin was less than 7m ( about 21ft. ), and species of the suspicion were just Nipponosaurus sachalinensis, Amurosaurus riabinini and Bactrosaurus johnsoni from Manchuria and Mongolia-Inner Mongolia. However, these three species were too far to nest, lay eggs and hatch in Tiantai Basin (of course, not rule out the possibility of their long-distance migration, though thers was no evidence heretofore). So the hadrosaur laid the Dendroolithus dendriticus likely was an undiscovered species. Furthermore, all of the Dendroolithus dendriticus were flat spherical eggs, and suggested that their eggshell were flexible as that of some modern reptiles, and would be transmogrified by gravity.更多还原