Abstract The Miocene fiddler crab Uca maracoani antiqua Brito, 1972, from the Pirabas Formation (Brazil), has been recurrently claimed to be a valid species and the oldest fossil record of the brachyuran crab family Ocypodidae. However, morphological investigations with the aid of microCT scan images of a large number of topotypic specimens and re-examination of the type material of U. maracoani antiqua revealed that it should actually be merged into the synonymy of Uca (Acanthoplax) maracoani (Latreille, 1802). Therefore, U. maracoani, the morphology and ecological traits of which have persisted essentially unchanged for at least 16 Ma (Burdigalian to present), is actually a long-lived crab species inhabiting an estuarine, sheltered mudflat environment that, likewise, has essentially remained unchanged. Burgeoning evidence suggests that evolutionary stasis may not be uncommon among mangrove crabs, as revealed by Afruca tangeri (Eydoux, 1835) from the middle Miocene in northeastern Spain and U. ornata (Smith, 1870) from the Plio-Pleistocene in Honduras. Uca antiqua is redescribed and illustrated based on 3D volume reconstruction and several topotypic specimens. The microCT analysis revealed a considerable number of fossil concretions of U. maracoani, with both males and females likely sharing the same burrow. This is the first fossil record of a male fiddler crab with a female inside a burrow, where mating usually takes place. This mating style is common to almost all extant American fiddler crabs.

中文翻译：

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来自巴西中新世古红树林的 Uca maracoani（甲壳纲、十足目、Ocypodidae）：热带美洲招潮蟹进化停滞的案例

摘要 1972 年，来自巴西皮拉巴斯组的中新世招潮蟹 Uca maracoani antiqua Brito 被反复声称是短尾蟹科 Ocypodidae 的有效物种和最古老的化石记录。然而，借助大量拓扑标本的显微CT扫描图像和U. maracoani antiqua类型材料的形态学研究发现，它实际上应该并入Uca (Acanthoplax) maracoani (Latreille, 1802）。因此，U. maracoani，其形态和生态特征在至少 16 Ma（布尔迪加尔至今）基本保持不变，实际上是一种长寿蟹种，栖息在河口、遮蔽的泥滩环境中，同样，该环境基本上保持不变。不变。新兴的证据表明，进化停滞在红树林蟹中可能并不少见，正如来自西班牙东北部中中新世的 Afruca tangeri（Eydoux，1835）和来自洪都拉斯的上新世的 U. ornata（Smith，1870）所揭示的那样。基于 3D 体积重建和几个拓扑标本重新描述和说明了 Uca antiqua。显微 CT 分析揭示了大量乌鸦的化石结核，雄性和雌性可能共用同一个洞穴。这是第一个雄性招潮蟹的化石记录，雌性招潮蟹通常在洞穴中进行交配。这种交配方式在几乎所有现存的美国招潮蟹中都很常见。ornata (Smith, 1870) 来自洪都拉斯的上新世。基于 3D 体积重建和几个拓扑标本重新描述和说明了 Uca antiqua。显微 CT 分析揭示了大量乌鸦的化石结核，雄性和雌性可能共用同一个洞穴。这是第一个雄性招潮蟹的化石记录，雌性招潮蟹通常在洞穴中进行交配。这种交配方式在几乎所有现存的美国招潮蟹中都很常见。ornata (Smith, 1870) 来自洪都拉斯的上新世。基于 3D 体积重建和几个拓扑标本重新描述和说明了 Uca antiqua。显微 CT 分析揭示了大量乌鸦的化石结核，雄性和雌性可能共用同一个洞穴。这是第一个雄性招潮蟹的化石记录，雌性招潮蟹通常在洞穴中进行交配。这种交配方式在几乎所有现存的美国招潮蟹中都很常见。这是第一个雄性招潮蟹的化石记录，雌性招潮蟹通常在洞穴中进行交配。这种交配方式在几乎所有现存的美国招潮蟹中都很常见。这是第一个雄性招潮蟹的化石记录，雌性招潮蟹通常在洞穴中进行交配。这种交配方式在几乎所有现存的美国招潮蟹中都很常见。