Abstract:
The small pseudosuchian Benggwigwishingasuchus eremacarminis was found in Anisian (Middle Triassic) marine sediments. Neither the skeleton nor osteohistology or microanatomy shows any secondary aquatic adaptations, and a dominantly terrestrial lifestyle of this new taxon is evident. Bone tissue consists of a scaffold of parallel-fibered matrix, which is moderately vascularized by small, mainly longitudinal primary osteons. The innermost cortex is less densely vascularized and more highly organized. No parts of the cortex contain any woven bone. The cortex is regularly stratified by annual growth marks. Bone tissue and growth pattern indicate an adult individual that has had slow growth rates throughout its ontogeny. Tissue type, slow growth rate, and inferred low resting metabolic rate of Benggwigwishingasuchus are similar to that of crocodylomorphs but differ from that of Sillosuchus and Effigia, poposaurids to which Benggwigwishingasuchus is related based on phylogenetic analyses. However, according to current knowledge, growth rates in early archosaurs are more likely influenced by body size and environment than by phylogeny. Benggwigwishingasuchus is thus another example of unpredictable variability in growth rates within Triassic archosaurs.
摘要:
在阿尼西亚(中三叠纪)海洋沉积物中发现了小的伪SudosuchianBenggwigwishingasuchuseremacarminis。骨骼,骨组织学或显微解剖学均未显示任何继发性水生适应,这种新分类群的主要陆地生活方式是显而易见的。骨组织由平行纤维基质的支架组成,适度血管化,主要是纵向原发性骨。最内层的皮质血管化密度较低,组织化程度更高。皮质的任何部分都不包含任何编织骨。皮层有规律地按年生长标记分层。骨组织和生长模式表明成年个体在整个个体发育过程中生长速度缓慢。组织类型,生长速度缓慢,推断Benggwigwishingasuchus的静息代谢率低,与鳄鱼的相似,但与Sillosuchus和Effigia不同,根据系统发育分析,Benggwigwishingasuchus与之相关的足龙。然而,根据目前的知识,早期恐龙的生长速度更可能受体型和环境的影响,而不是受系统发育的影响。因此,Benggwigwishingasuchus是三叠纪龙中生长速度不可预测的变化的另一个例子。