Despite the diversity in the size, performance, and function of crustacean claws (chelae), our understanding of the functional morphology and evolution of these claws are lacking. Since crayfish claws are multi-function organs that face selection from fighting, mating, foraging, and predation, these pressures all interact to shape the claws morphology and performance. I studied a unique claw morphology, the exaggerated claw gape of the New River crayfish, Cambarus chasmodactylusJames, 1966, by investigating how this claw morphology relates to claw strength and fighting style. Claw length increased in both males and females as body size increased, although this trend was more pronounced in males, and maximal claw strength increased as claw length increased in both males and females. I describe the fighting behavior of the species in relation to previously studied species and speculate on how changes in claw morphology have led to changes in species-specific fighting style. Observations of fighting behavior in C. chasmodactylus revealed a previously undescribed claw grasping behavior, in which competitors grasp onto the manus of their opponent’s claw and laterally twist to flip their opponent. When assessing the relative role of claw size and claw strength on contest success in male individuals, individuals with larger, but not necessarily stronger claws were most likely to attain dominance. These results highlight the functional morphology of a unique claw morphology and provides initial evidence for how claw form relates to fighting style within decapod crustaceans.

中文翻译：

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新河螯虾 Cambarus chasmodactylus James 的爪形态、爪强度和战斗行为，1966 年（十足目：Astacoidea：Cambaridae）

尽管甲壳动物爪 (chelae) 的大小、性能和功能各不相同，但我们对这些爪的功能形态和进化的理解仍然缺乏。由于小龙虾爪是多功能器官，面临从战斗、交配、觅食和捕食的选择，这些压力都相互作用以塑造爪的形态和性能。我研究了一种独特的爪子形态，即新河螯虾 Cambarus chasmodactylusJames，1966 年的夸张爪张，通过研究这种爪子形态与爪力和战斗方式的关系。雄性和雌性的爪长随着体型的增加而增加，尽管这种趋势在雄性中更为明显，并且随着雄性和雌性爪长的增加，最大爪强度增加。我描述了该物种相对于先前研究的物种的战斗行为，并推测爪形态的变化如何导致特定物种战斗风格的变化。对 C. chasmodactylus 战斗行为的观察揭示了一种先前未描述的爪抓行为，其中竞争对手抓住对手爪的手部并横向扭转以翻转对手。在评估爪子大小和爪子力量对男性比赛成功的相对作用时，爪子更大但不一定更强壮的人最有可能获得支配地位。这些结果突出了独特爪形的功能形态，并为爪形如何与十足目甲壳类动物的战斗风格相关提供了初步证据。