Evolution of incisor enamel microstructure in Theridomyidae (Rodentia)
Evolution of incisor enamel microstructure in Theridomyidae (Rodentia)
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DOI：
10.1080/02724634.1999.10011164
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发表时间：
1999-09-14
影响因子：
1.4
通讯作者：
Martin, T
中科院分区：
文献类型：
--
作者：
Martin, T
始新世中后期 (MP 13-17) 的最早代表兽科动物（属于 Issiodoromyinae、Theridomyinae、Sciuroidinae、Pseudosciurinae 和 Remyinae 亚科）具有类似形的稀疏门牙 schmelzmuster。至少从渐新世早期（MP 22）开始，Issiodoromyinae 就发展出了一种完全单列的 schmelzmuster。 Pseudoltinomys Phosricus (Issiodoromyinae, MP 17) 表现出具有不规则交叉棱柱的 schmelzmuster，很可能源自贫亨特-施雷格带 (HSB)。在兽蝽亚科中，兽蝽属保留了原始的 pauciserial schmelzmuster 和稍微稀疏的 HSB。在 Blainvillimys 和 Archaeomys 属（趋同于 Hystricognathi 和派生的 Ctenodactyloidea）中，开发了具有伪多系列 HSB 的 schmelzmuster（MP 23-30）。这种情况与在缺颌啮齿类动物的门牙中发现的具有多系列 HSB 的 schmelzmuster 存在许多明显的差异：HSB 厚度较低，内部 (PI) 中棱柱间基质 (IPM) 的角度较小，以及外部 (PE) 更厚。与这种伪多序列牙釉质一样，Theridomyidae 中的单序列 schmelzmuster 仍然相对原始，并且在其 HSB 中仅实现了具有锐角 IPM 的阶段。父齿鼠 (Theridomyinae) 和外皮鼠 (Oltinomyinae) 具有垂直方向的 HSB。颊齿的低齿性等级与来自准形性贫牙状态的切牙牙釉质中的单序列和伪多序列 HSB 的发育之间存在密切的对应关系。兽科 (Theridomyidae) 从啮齿动物基础分支（Ischyromyoidea 或 Ctenodactyloidea）中分离出来。
The earliest representatives of Theridomyidae (belonging to the subfamilies Issiodoromyinae, Theridomyinae, Sciuroidinae, Pseudosciurinae, and Remyinae) from the Middle to Late Eocene (MP 13-17) have a plesiomorphic pauciserial incisor schmelzmuster. Within Issiodoromyinae at least since the Early Oligocene (MP 22) a fully uniserial schmelzmuster is developed. Pseudoltinomys phosphoricus (Issiodoromyinae, MP 17) exhibits a schmelzmuster with irregular decussation of prisms most probably derived from pauciserial Hunter-Schreger bands (HSB). Within Theridomyinae, the genus Theridomys retains the primitive pauciserial schmelzmuster with somewhat thinned HSB. In the genera Blainvillimys and Archaeomys, convergent to Hystricognathi and derived Ctenodactyloidea, a schmelzmuster with pseudo-multiserial HSB was developed (MP 23-30). This condition includes a number of clear differences to the schmelzmuster with multiserial HSB found in the incisors of hystricognath rodents: lower HSB thickness, lower angle of interprismatic matrix (IPM) in the portio interna (PI), and a much thicker portio externa (PE). As in this pseudo-multiserial enamel, the uniserial schmelzmuster in the Theridomyidae remains comparatively primitive, and in its HSB only a stage with acute angular IPM is achieved. Patriotheridomys (Theridomyinae) and Ectropomys (Oltinomyinae) have vertically oriented HSB. There exists a close correspondence between the grade of hypsodonty of the cheek teeth and the development of uniserial and pseudo-multiserial HSB in the incisor enamel from the plesiomorphic pauciserial condition. Theridomyidae split off from basal rodent clades (Ischyromyoidea or Ctenodactyloidea).