Brain and sense organ anatomy and histology of two species of phyletically basal non‐Antarctic thornfishes of the Antarctic suborder Notothenioidei (Perciformes: Bovichtidae)
Abstract The predominantly non‐Antarctic family Bovichtidae is phyletically basal within the perciform suborder Notothenioidei, the dominant component of the Antarctic fish fauna. In this article we focus on the South Atlantic bovichtids Bovichtus diacanthus, the klipfish from tide pools at Tristan...
| Published in: | Journal of Morphology |
|---|---|
| Main Authors: | , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Wiley
2007
|
| Subjects: | |
| Online Access: | http://dx.doi.org/10.1002/jmor.10534 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fjmor.10534 https://onlinelibrary.wiley.com/doi/pdf/10.1002/jmor.10534 |
| Summary: | Abstract The predominantly non‐Antarctic family Bovichtidae is phyletically basal within the perciform suborder Notothenioidei, the dominant component of the Antarctic fish fauna. In this article we focus on the South Atlantic bovichtids Bovichtus diacanthus, the klipfish from tide pools at Tristan da Cunha, and Cottoperca gobio, the frogmouth from the Patagonian shelf and Falkland Islands. We document the anatomy and histology of the brains, olfactory apparatus, retina, and cephalic lateral line system. We also use the microvascular casting agent Microfil® to examine ocular vascular structures. We provide detailed drawings of the brains and cranial nerves of both species. Typical of perciforms, the brains of both species have a well‐developed tectum and telencephalon and robust thalamic nuclei. The telencephalon of C. gobio is prominently lobed, with the dorsomedial nucleus more conspicuous than in any other notothenioid. The corpus cerebelli is relatively small and upright and, unlike other notothenioids, has prominent transverse sulci on the dorsal and caudal surfaces. Areas for lateral line mechanoreception (eminentia granularis and crista cerebellaris) are also conspicuous but olfactory, gustatory, and somatosensory areas are less prominent. The anterior lateral line nerve complex is larger than the posterior lateral line nerve in B. diacanthus, and in their cephalic lateral line systems both species possess branched membranous tubules (which do not contain neuromasts) with small pores. These are especially complex in B. diacanthus where they become increasingly branched and more highly pored in progressively larger specimens. Superficial neuromasts are sparse. Both species have duplex (cone and rod) retinae that are 1.25‐fold thicker and have nearly 5‐fold more photoreceptors and than those of most Antarctic notothenioids. Convergence ratios are also high for bovichtids. Bovichtus diacanthus has a yellow intraocular filter in the dorsal aspect of the cornea. Both species are unique among notothenioids in ... |
|---|