Department of Earth Sciences, Museum of Natural History, Cromwell Road, London, SW7 5BD, UK. .
Department of Earth and Planetary Sciences, University of California, Riverside, CA 92521, USA. Department of Geography and Environmental Studies, Texas State University, San Marcos, TX 78666, USA.
Zootaxa. 2022 Jul 8;5162(4):301-356. doi: 10.11646/zootaxa.5162.4.1.
The field collections made from Burma (Myanmar) by the Geological Survey of India, and described by F.R.C. Reed more than a century ago, still provide the only ground truthing for an important region of the Ordovician marginal terranes fringing Gondwana. A revision of these faunas is overdue, particularly as it is likely that further collections cannot be made in the northern Shan State in the near future. The specimens, stored in the Geological Survey of India collections in Kolkata, cannot be loaned. Sixteen species are fully revised herein; another twelve species are left under open nomenclature because of inadequacies in the material. Several of Reeds species subsequently became type species of genera that have proved to be widespread: Birmanites Sheng, 1934, Encrinurella Reed, 1915, Neseuretinus Dean, 1967, and Pliomerina Chugaeva, 1956. Reeds Ordovician trilobite collections came from two main areas: northern Shan State (Myanmar), and westernmost Yunnan (China). The Burmese (Myanmar) collections are from the Upper Ordovician (Katian) while Yunnan specimens are from the Middle Ordovician (Darriwilian), though Upper Ordovician trilobites also occur in the area. Both collections are predominantly from clastic strata. Based on a small new Katian collection from Pupiao, we report Neseuretinus birmanicus (Reed, 1906) in common between the northern part of the Shan State and western Yunnan. A few genera (Dionide Barrande, 1847, Phorocephala Lu, 1957, Lonchodomas Angelin, 1854, Nileus Dalman, 1827) are distributed worldwide, and include pelagic (Phorocephala) or deeper benthic (Dionide) taxa. The palaeogeographic comparisons offered by the other taxa are mostly peri-Gondwanan and extend from southwest China westwards (present geography) as far as the Iberian Pennsula. Birmanites is the type genus of a subfamily (Birmanitinae Kobayashi, 1960, revived herein) widely distributed over Ordovician Gondwana, and absent from Laurentia, Baltica and North China/Siberia. Mioptychopyge Zhou, Dean, Yuan Zhou, 1998, probably belongs with the same group and is otherwise known from South China. Parillaenus Jaanusson, 1954, is also peripheral Gondwanan, as is Prionocheilus Rouault, 1847. The Reedocalymeninae Kobayashi, 1951 (Neseuretinus, Reedocalymene Kobayashi, 1951) are similarly diagnostic of periGondwanan sites. However, some genera (Pliomerina, Encrinurella, Ovalocephalus Koroleva, 1959) have been associated with other oriental and Australian occurrences in particular, with outliers in certain terranes in Kazakhstan, i.e. palaeotropical Gondwana.
印度地质调查局从缅甸（缅甸）采集的实地标本，并由 F.R.C.里德一个多世纪前进行了描述，仍然是冈瓦纳边缘地体奥陶纪边缘地体的一个重要区域的唯一实地验证。这些动物群的修订工作已经过时，特别是因为在不久的将来，可能无法在缅甸北部掸邦进行进一步的采集。这些标本存放在加尔各答的印度地质调查局收藏中，无法借出。本文对 16 个物种进行了全面修订；由于材料不足，另外 12 个物种仍保留开放命名。里德的几个物种后来成为被证明分布广泛的属的模式种：Birmanites Sheng, 1934、Encrinurella Reed, 1915、Neseuretinus Dean, 1967 和 Pliomerina Chugaeva, 1956。里德的奥陶纪三叶虫标本来自两个主要地区：北部掸邦（缅甸）和最西端的云南（中国）。缅甸（缅甸）的采集标本来自上奥陶统（卡蒂安期），而云南的标本来自中奥陶统（达里瓦利期），尽管该地区也有上奥陶统三叶虫。两个集合主要来自碎屑地层。基于来自 Pupiao 的一个小型新的 Katian 集合，我们报告 Neseuretinus birmanicus（Reed，1906）在掸邦北部和云南西部之间共同存在。少数属（Dionide Barrande，1847、Phorocephala Lu，1957、Lonchodomas Angelin，1854、Nileus Dalman，1827）分布于世界各地，包括远洋（Phorocephala）或更深的底栖（Dionide）分类群。其他分类群提供的古地理比较主要是冈瓦纳周边地区，从中国西南部向西延伸（当前地理），直到伊比利亚半岛。Birmanites 是一个亚科（Birmanitinae Kobayashi，1960，在此恢复）的模式属，广泛分布于奥陶纪冈瓦纳，而在劳伦西亚、波罗的海和华北/西伯利亚不存在。Mioptychopyge Zhou、Dean、Yuan Zhou，1998，可能与同一组有关，否则仅见于华南。Parillaenus Jaanusson，1954，也是冈瓦纳周边地区，与 Prionocheilus Rouault，1847 一样。Reedocalymeninae Kobayashi，1951（Neseuretinus、Reedocalymene Kobayashi，1951）同样可用于鉴别冈瓦纳周边地区的地点。然而，一些属（Pliomerina、Encrinurella、Ovalocephalus Koroleva，1959）与东方和澳大利亚的其他地区有关，特别是在哈萨克斯坦的某些地体中存在离群种，即古热带冈瓦纳。
