Holocentrus sheppeyensis
Holocentrus sheppeyensis
Summary
Holocentrus sheppeyensis was a holocentrid, or squirrelfish relative, known from London Clay otoliths. Living holocentrids are mainly nocturnal marine predators that feed on small crustaceans and fishes, often around structured habitats. A comparable trophic role is possible for the Eocene species, although only the inner-ear stones are known and no direct evidence of behaviour or diet is preserved.
Its relatively large, elongate sagittal otolith has a long supramedian sulcus and strongly convex inner face. The record shows that holocentrid lineages formed part of the diverse early Eocene acanthomorph fauna of the London Clay sea.
Quick Identification
Look for: a comparatively large, very elongate holocentrid otolith with a strongly convex smooth inner face, a long narrow sulcus positioned above the midline and a pointed posterior end; the dorsal margin may carry modest ornament centrally.
Diagnostic Features
- Otolith length is more than about 1.9 times its height.
- Inner face is strongly convex and relatively smooth.
- Sulcus is long, narrow and distinctly supramedian.
- Posterior end forms a pointed, slightly ornamented tip.
- Dorsal and ventral margins are broadly regular, with ornament concentrated mainly near the middle of the dorsal rim.
Fossil Details
Recorded Fossil Sites
London Clay Formation
References
- Schwarzhans, W. (2007). The otoliths from the Middle Eocene of Osteroden near Bramsche, north-western Germany. Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen, 244(3), 299–369 View reference
- Steurbaut, E.; Nolf, D. (1988). Ypresian teleost otoliths from Belgium and northwestern France. Bulletin de la Société belge de Géologie, 97(3–4), 321–347 View reference
- Stinton, F. C. (1966). Fish otoliths from the London Clay. Faune ichthyologique du London Clay, 404–464. British Museum (Natural History), London View reference