Notosuchian crocodyliforms represent an intriguing group since they are mainly terrestrial forms and therefore with completely different lifestyles than extant crocodylian, which is reflected in their particular skeletal anatomy. Although there are some inferences in the literature related to the palaeoecology of notosuchian, little is known about their biology (e.g. metabolism, growth dynamics). The palaeohistology allows us to perform interpretations about the growth dynamics and strategies of growth in these extinct forms. Here, we worked on specimens of Araripesuchus Price, 1959 (Notosuchia, Uruguaysuchidae), coming from La Buitrera Palaeontological Area, Río Negro Province (northern Patagonia, Argentina). We described for the first time the osteohistology of this taxon, based on thin sections of the stylopodium shaft (femur and humerus) of four specimens, providing an assumption of its growth dynamics. A general slow growth rate is inferred for Araripesuchus, based on the poorly vascularized parallel-fibred/lamellar bone matrix. An unusual pattern of bone deposition was observed in two specimens; we consider this tissue as evidence of a rapid growth event at some point in the ontogeny of these individuals. Finally, it can be interpreted that in Araripesuchus, sexual maturity could be reached at least between eight to thirteen years old. This study is a first step to provide insight into the life history of these terrestrial notosuchids and to provide new empirical evidence for the osteohistological variability and palaeoecology of this peculiar group of extinct crocodyliforms.

中文翻译：

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Notosuchian Araipesuchus Price 的古骨组织学和生长动态的新数据，1959

Notosuchian 鳄鱼代表了一个有趣的群体，因为它们主要是陆地形式，因此与现存的鳄鱼有着完全不同的生活方式，这反映在它们特定的骨骼解剖结构上。尽管文献中有一些与河豚古生态学相关的推论，但对其生物学（例如新陈代谢、生长动力学）知之甚少。古组织学使我们能够对这些灭绝形式的生长动态和生长策略进行解释。在这里，我们研究了Aaripesuchus的标本Price, 1959 (Notosuchia, Uruguaysuchidae), 来自里奥内格罗省 (巴塔哥尼亚北部, 阿根廷) 的 La Buitrera 古生物区。我们首次描述了该分类群的骨组织学，基于四个标本的花柱基轴（股骨和肱骨）的薄切片，提供了其生长动力学的假设。基于血管化不良的平行纤维/板层骨基质，推断Araipesuchus的生长速度普遍缓慢。在两个样本中观察到不寻常的骨沉积模式；我们认为这种组织是这些个体个体发育过程中某个阶段快速生长事件的证据。最后，可以解释为在Araipesuchus，性成熟至少可以在八到十三岁之间达到。这项研究是深入了解这些陆生条鳄的生活史并为这一特殊灭绝鳄鱼类群的骨组织学变异性和古生态学提供新的经验证据的第一步。