Several species of Cophomantini are known to have an enlarged prepollex, commonly modified as an osseous spine. We surveyed the osteology and myology of the prepollex and associated elements of 94 of the 190 species of Cophomantini, sampling all genera, except Nesorohyla. Two distinct prepollex morphologies were found: a blade-shaped and a spine-shaped morphology. We described the observed variation in 17 discrete characters to study their evolution in the most inclusive phylogenetic hypothesis for Cophomantini. Both morphologies evolved multiple times during the evolutionary history of this clade, but the origin of the spine-shaped distal prepollex in Boana and Bokermannohyla is ambiguous. The articulation of metacarpal II with the prepollex through a medial expansion of the metacarpal proximal epiphysis is a synapomorphy for Boana. The shape of the curve of the spine, and a large post-articular process of the distal prepollex, are synapomorphies for the Boana pulchella group, the latter being homoplastic in the Bokermannohyla martinsi group. Muscle character states associated with the spine-shaped prepollex are plesiomorphic for Cophomantini. We discuss evolution, function, behaviour and sexual dimorphism related to the prepollical elements. A bony spine is associated with fights between males, but forearm hypertrophy could be more related with habitat than with territorial combat.

中文翻译：

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Cophomantini (Anura: Hylidae: Hylinae)的花粉前体多样性和进化

已知几种 Cophomantini 具有扩大的前花粉，通常被修饰为骨棘。我们调查了 190 种 Cophomantini 中的 94 种的前花粉和相关元素的骨学和肌肉学，采样了除 Nesorohyla 之外的所有属。发现了两种不同的花粉前形态：叶片形和棘形形态。我们描述了观察到的 17 个离散特征的变异，以研究它们在 Cophomantini 最具包容性的系统发育假设中的演变。在这个进化枝的进化历史中，这两种形态都进化了多次，但 Boana 和 Bokermannohyla 的脊柱形远端前花粉的起源是模棱两可的。通过掌骨近端骨骺的内侧扩张将掌骨 II 与前指关节连接是 Boana 的突触。脊柱曲线的形状和远端前指的大关节后突是 Boana pulchella 组的突触，后者在 Bokermannohyla martinsi 组中是同质的。与脊柱形前指相关的肌肉特征状态对于 Cophomantini 来说是同形的。我们讨论与前民意元素相关的进化、功能、行为和性别二态性。脊椎骨与雄性之间的争斗有关，但前臂肥大可能与栖息地有关，而不是与领土争斗有关。与脊柱形前指相关的肌肉特征状态对于 Cophomantini 来说是同形的。我们讨论与前民意元素相关的进化、功能、行为和性别二态性。脊椎骨与雄性之间的争斗有关，但前臂肥大可能与栖息地有关，而不是与领土争斗有关。与脊柱形前指相关的肌肉特征状态对于 Cophomantini 来说是同形的。我们讨论与前民意元素相关的进化、功能、行为和性别二态性。脊椎骨与雄性之间的争斗有关，但前臂肥大可能与栖息地有关，而不是与领土争斗有关。