Department of Evolutionary Biology and Coservation of Vertebrates, University of Wroclaw, Wrocław, Poland.
PeerJ. 2023 Oct 18;11:e16266. doi: 10.7717/peerj.16266. eCollection 2023.
Sexual dimorphism in size and shape is widespread among squamate reptiles. Sex differences in snake skull size and shape are often accompanied by intersexual feeding niche separation. However, allometric trajectories underlying these differences remain largely unstudied in several lineages. The sea krait (Serpentes: Elapidae) exhibits very clear sexual dimorphism in body size, with previous studies having reported females to be larger and to have a relatively longer and wider head. The two sexes also differ in feeding habits: males tend to prey in shallow water on muraenid eels, whereas females prey in deeper water on congerid eels.
I investigated sexual dimorphism in skull shape and size as well as the pattern of skull growth, to determine whether males and females follow the same ontogenetic trajectories. I studied skull characteristics and body length in 61 male and female sea kraits.
The sexes differ in skull shape. Males and females follow distinct allometric trajectories. Structures associated with feeding performance are female-biased, whereas rostral and orbital regions are male-biased. The two sexes differ in allometric trajectories of feeding-related structures (female biased) that correspond to dietary divergence between the sexes.
Sea kraits exhibit clear sexual dimorphism in the skull form that may be explained by intersexual differences in the feeding habits as well as reproductive roles. The overall skull growth pattern resembles the typical pattern observed in other tetrapods.
大小和形状的性二态性在有鳞目爬行动物中广泛存在。蛇类头骨大小和形状的性别差异通常伴随着雌雄食性生态位的分离。然而，在一些谱系中，这些差异背后的异速生长轨迹在很大程度上仍未得到研究。海蛇（蛇目：眼镜蛇科）在体型上表现出非常明显的性别二态性，以前的研究报告称，雌性更大，头部相对更长更宽。两性在饮食习惯上也存在差异：雄性倾向于在浅水区以鳗鲡为食，而雌性则在深水区以海鳗为食。
我研究了头骨形状和大小的性别二态性以及头骨生长模式，以确定雄性和雌性是否遵循相同的个体发育轨迹。我研究了 61 条雄性和雌性海蛇的头骨特征和体长。
两性的头骨形状存在差异。雄性和雌性遵循不同的异速生长轨迹。与摄食性能相关的结构偏向雌性，而吻部和眶部偏向雄性。两性在与摄食相关的结构（雌性偏向）的异速生长轨迹上存在差异，这与两性之间的饮食差异相对应。
海蛇的头骨形态存在明显的性别二态性，这可能是由于两性在饮食习惯和生殖角色上的差异造成的。总的头骨生长模式类似于其他四足动物中观察到的典型模式。
