BEACHCOMBING AT THE DELPHI CLUB, ABACO – CORAL & NERITES


CONTRASTING CORAL SKELETONS

These two different types of coral skeleton are from the northern end (and just beyond) of the Delphi beach. The red marking on the second coral is some kind of natural accretion, I think – I have temporarily lost the exact details somewhere on my hard drive, but doubtless they will turn up sooner or later… You will find these red patches on shells as well as coral

COMMON ROSE CORAL

ANY IDEAS  - OR IS THIS WORM-RELATED?

Another dramatic coral you may come across – not least because there are usually one or two in the beach-harvested collection on the steps down to the beach – is Brain Coral (Diploria). Here is an example (Photo credit J. Stuby)

NERITES (Nerita)

Nerites are small sea-snails (gastropod molluscs) found in tropical waters around the world. Precise ID of the many types is confused by the different names used for many of them, both taxonomic and local. The majority of the black and white nerites in the pile below, all collected from the Delphi beach, are Checkered Nerites (Nerita Tessellata). In the heap there are a few larger whiter shells with red markings, which are the Four-Toothed Nerite (Nerita Versicolor).

Here are some of the above shells showing their varying patterns and sizes, seen with a few grains of sand for comparison. The 3 larger whiter ones with the flecks of red on them are the Four-Toothed Nerites.

Here are 3 example shells in close-up, together with a tiny, perfect Dwarf Atlantic Planaxis (Hinea lineata) at the end (previously misidentified as a Littorine). I didn’t notice it until I was sorting through the shells – in fact you can just see it towards the bottom right of the previous photo, above the small nerite that’s on its back. It may even have fallen out of a nerite, as did many of the sand grains.

These four upturned nerites show the dentate entrance, common (to a greater or lesser extent) to most nerites – maybe all. The top row are Four-toothed Nerites; the bottom row are Checkered Nerites. Another Nerite type found in the Bahamas is the Bleeding-tooth nerite (Nerita Peloronta). These are similar to the top ones, but have vivid orangey-red markings on the ‘teeth’ – hence their name.

Nerites, sand grains and the Planaxis: size comparison

A close up of the Planaxis, showing how amazingly detailed the pattern of such a tiny shell can be

All this may sound a bit learned and somewhat solemn. Dull even. In fact I had absolutely no idea about any of the above details until I got these shells out of their glass jar last week to photograph (apologies for using a chopping board) and did some digging… So if any shellologists or neritophiles read this and have corrections to suggest, be my guest… Use the comment box or the email address on the CONTACT page. ADDENDUM: many thanks to Colin Redfern for confirming the small nerites as Checkered, as opposed to Zebra; and the ‘littorine’ as a Dwarf Atlantic Planaxis Hinea lineata