Because sister species share a phenotypic axis, they hold morphological and ecological traits in common and, when sympatric, are ideal subjects for examining the extent of morphological divergence associated with the non-shared ecological parameters of the niche. Trematomus lepidorhinus and T. loennbergii have overlapping depth ranges of > 1000 m and occupy the deep shelf-upper slope niche in the waters of East Antarctica, an area where glacial troughs and their 1000–1500 m-deep landward basins (innershelf depressions) encompass 40% of the sea floor. The sense organ and brain divergence between the two species at the gross anatomical and histological levels involves differences in: number of olfactory lamellae, composition of the photoreceptor array and the number of retinal cells, size of the cephalic lateral line pores, and overall size of the brain and degree of development of different brain regions. Size and shape of the sagittal otoliths also differ. The morphology is unequivocally differentiating for habitat depths and conclusively documents a shift toward reliance on non-visual senses in T. loennbergii, consistent with collection data indicating this species lives at greater depths than T. lepidorhinus. Depths of peak abundances—200–500 m for T. lepidorhinus and 600–800 m for T. loennbergii—are the major differentiating parameter, with the ≈300 m differential between the peaks providing considerable, although not absolute, habitat separation. This is also reflected in the greater absolute abundances of the shallower-living T. lepidorhinus in trawl catches. Only T. loennbergii is found near the floors of 1000–1500 m-deep innershelf depressions, a distinctive microhabitat on the high latitude shelf.

由于姊妹物种共有一个表型轴，因此它们具有共同的形态和生态特征，当同胞时，是检查与生态位非共享生态参数有关的形态差异程度的理想对象。沙眼银耳和T. loennbergii具有> 1000 m的重叠深度范围，并占据了南极东部水域的深层架子-上部斜坡壁iche，该地区的冰川槽及其深达1000-1500 m的陆上盆地（内陆凹陷）占海床的40％ 。两种动物在总体解剖学和组织学水平上的感觉器官和大脑差异涉及以下方面的差异：嗅觉片的数量，感光体阵列的组成和视网膜细胞的数量，头侧线孔的大小以及大脑和不同大脑区域的发育程度。矢状耳石的大小和形状也不同。形态明确地区分了栖息地深度，并最终证明了对T. loennbergii的非视觉感的依赖，与收集数据一致，表明该物种的生活深度比鳞翅目T. lepidorhinus大。峰丰度的深度（鳞翅目T. lepidorhinus为200–500 m，而卢氏T. loennbergii为600–800 m ）是主要的区分参数，峰之间的差异约为300 m，可提供相当大的，但不是绝对的生境分离。拖网捕捞中生活在浅层的T. lepidorhinus的绝对丰度更高也反映了这一点。仅在接近1000-1500 m深的内架凹陷的地板附近发现了T. loennbergii，这是高纬度货架上一种独特的微生境。