Evolutionary Morphology of Vertebrates, Ghent University, K.L. Ledeganckstraat 35, B-9000 Ghent, Belgium.
Zoology (Jena). 2010 May;113(3):148-57. doi: 10.1016/j.zool.2009.09.004. Epub 2010 May 1.
Hoplunnis punctata, a member of the Anguilliformes, is a long-snouted eel that lives in benthic habitats of the continental shelf of tropical waters. The purpose of this study was to examine the skull morphology of this little known nettastomatid and to understand the changes associated with jaw elongation as well as the implications of jaw elongation on the feeding apparatus. We present a detailed description of the cranial osteology and myology of H. punctata and how these characters differ from Conger conger (Congrinae: Congridae), a representative with moderate jaw length, and Heteroconger hassi (Heterocongrinae: Congridae), a representative with a short jaw. Shape comparison shows a caudal displacement of the hyomandibula, quadrate-mandibular articulation and opercle-hyomandibular joint, decrease in the depth of the neurocranium, and increase in the distance between the anterior suspensorial facet and the posterior end of the orbit in H. punctata as a result of jaw elongation. These characteristics along with its immobile, long maxillary and well-developed adductor mandibulae muscle complex suggest that food may be obtained by powerful biting. Jaw elongation potentially affects the functioning of the feeding apparatus in H. punctata by providing more space for the olfactory rosette, increasing biting speed and reducing drag during prey capture.
点斑六鳃鳗，属于鳗鲡形目，是一种长鼻鳗，生活在热带水域大陆架的底栖生境中。本研究的目的是研究这种鲜为人知的囊鳃鳗的头骨形态，并了解与下颚伸长相关的变化以及下颚伸长对摄食器官的影响。我们详细描述了点斑六鳃鳗的颅骨骨骼学和肌肉学，以及这些特征与具有中等下颚长度的代表种康吉鳗（Congrinae：Congridae）和具有短下颚的代表种哈氏异康吉鳗（Heterocongrinae：Congridae）的差异。形状比较表明，由于下颚伸长，点斑六鳃鳗的舌颌骨、方骨-下颌关节和鳃盖-舌颌骨关节向后位移，颅神经腔变浅，前悬附突和眼眶后端之间的距离增大。这些特征以及其不可移动的长上颌和发达的颌内收肌复合体表明，它可能通过强有力的咬噬来获取食物。下颚伸长可能通过为嗅球提供更多空间、提高咬噬速度和减少猎物捕获过程中的阻力，从而影响点斑六鳃鳗摄食器官的功能。
