Tag Archives: Abaco Beachcombing

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PETERSON CONCISE GUIDE TO SHELLS OF NORTH AMERICA: REVIEW

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PETERSON CONCISE GUIDE TO THE SHELLS OF NORTH AMERICA

This pocket guide is part of the well-known Peterson series of natural history guides. It’s called a ‘First Guide’ to denote its ‘beginner’ / condensed status, and to distinguish it from the serious business of the excellent and comprehensive Peterson Field Guides (I shall review 2 of these in due course. When I have read them. In 2012).                                  rh rating **

SUMMARY: this 128pp ‘concise field guide to 224 common shells of North America’ is a simple pocket guide, with quite basic descriptions, and colour drawings rather than photos. All the main gastropod and bivalve species are represented, each with a few variants. The vast majority of these will be found on Abaco and more generally in the northern Bahamas. For the used price I paid for a 1989 edition with a creased front cover (1 pence + P&P on Amazon UK!) I have actually found it quite useful for comparing or confirming IDs, or for snippets of additional information. However, it’s not the one to rely on entirely to identify your beachcombing finds or to get species details. Apart from anything else the illustration colouring is often somewhat approximate. At best, I’d say it’s a useful preliminary tool for ID on the beach if you don’t want to lug a much larger field guide around with you. Don’t use it for your doctoral thesis. Overall, some use, but not a great deal. There are better books: see FISH & SHELL BOOKS

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MUREX & TRITON SHELL COLLECTING ON ABACO WITH KASIA

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PAGE REWRITE IN PROGRESS

MUREX (MURICIDAE) & TRITONS (RANELLIDAE) 

1. MUREX SHELLS (Muricidae)

This is a vast family of shells worldwide, with many subspecies, each of which has many regional variations. Or even variations of the same subspecies on the same beach. Many have beautiful delicate spines or intricate shapes and elaborate patterns, like the pacific one shown

These molluscs are described as ‘voracious rock scavengers’ and exhibit uninhibited psychopathic tendencies. If you have a nervous disposition, stop reading here; Sam Peckinpah missed a great film collaboration with Jacques Cousteau with these vicious little creatures

10 ESSENTIAL YET GRISLY MUREX FACTS

  • Murex are highly carnivorous with rasping teeth, and drilling equipment for boring into the shells of their prey
  • A determined Murex may take up to 5 days to drill into its prey
  • Murex also use their foot to smother prey, or to crush it by using suction power
  • They eat clams by hoovering them up with their foot and smashing them on rocks to get at the occupant
  • They happily eat sea-floor carrion and sea-kill
  • Murex act in packs to carry out raids on unsuspecting beds of clams, which they feast on avidly
  • They are sexually wanton. Females store sperm from different males for many months, eventually producing embryos with different dads (I’m not making this up. I would like to have done so)
  • Cannibalism occurs. The kids are equally prone to extreme delinquency and are happy to eat each other when peckish
  • Some species of murex secrete a fluid that is believed to be used to drug their prey into paralysis
  • That same fluid (Murex / Mucus) is also used as a dye, ‘Tyrian’ or ‘Royal’ Purple, which can be ‘milked’ from a living murex (the Aztecs & Phoenicians did this). I’ll pass on that

NEW: VIDEO of how to obtain dye from a Murex

 KASIA’S BEACHCOMBED ABACO MUREX SKELETON

TWO MUREX SHELLS OF MINE (NOT FROM ABACO) FOR COMPARISON  DETAIL OF COLOUR & SHINE

2. TRITON SHELLS (RANELLIDAE)

KASIA’S TRITON TROPHY FROM CASUARINA, ABACO

Here is another shell from Kasia’s beachcombing in the Casuarina Point area on Abaco. I’ve never seen one like this. I thought it was a TROPHON, a variety of the huge MUREX family. As I wrote, there are more than 30 types of trophon world-wide, many with a similar configuration, though I hadn’t managed to find one with a similar colouring and shell growth-pattern yet. I invited  confirmation or correction, which Colin Redfern kindly provided. It is in fact a fine example of a…

 

DOG-HEAD TRITON Cymatium cynocephalum

ANGULAR TRITON Cymatium femorale                                                                                A different sort of triton found by Kasia


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BEACHCOMBING AT CASUARINA, ABACO, WITH KASIA – COWRIE / PHALIUM / CONCH

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 BEACHCOMBING AT CASUARINA WITH KASIA                    COWRIE / PHALIUM & CONCH

I recently posted some photos of starfish taken by Kasia at low tide near Casuarina point – see KASIAS’S STARFISH. Now it’s time for some beachcombing news from there. The sandbanks and bars in the Casuarina / Cherokee Sound area are a rich source of conchs, sand dollar tests and shells of many varieties when the tide is out. The sandy areas revealed as the water slowly recedes are extensive, and it is a great place to hunt for specimens (and for a lunchtime break from bonefishing…)

COWRIES / PHALIUM

1. RETICULATED COWRIE-HELMET Cypraecassis testiculus Here is a pretty example of this shell, a relative of the large phalium family and originally misidentified by me as a Phalium granulatum

2. MEASLED COWRIE  Macrocypraea zebra / Cypraea zebra Colin Redfern says of this example “Immature shells have transverse stripes that are later covered by a spotted layer (hence “measled”). It looks as if it’s beachworn rather than immature, so the outer layer has probably been worn away. You can see remnants of the spotted layer adjacent to the aperture.” 

STOP PRESS: by coincidence, while looking for a completely different type of shell online I have just happened upon this early 1800s engraving of a Cypraea Vespa, which is very similar to Kasia’s one

CONCH I’m trying not to overdo Conchs, which are probably everyone’s favourite shell to collect. But this one is a wonderful pink, and came with a surprise inhabitant… Is anyone at home?

Oh! A hermit crab seems to have moved in…

It’s shyer than this one (from an unnamed online source)

Finally, a useful method to transport one’s shell collection, maybe?

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ABACO BEACHCOMBING WITH KASIA: MYSTERY OBJECT

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MYSTERY OBJECT FROM AN ABACO BEACH

  

Here’s a strange item found by Kasia when she was beachcombing with Caroline Stahala

Their preliminary thought was that it formed some part of a turtle’s shell or skeletal anatomy

It is quite small (the coin above is 1 Euro) but amazingly intricate – developed in 2 symmetrical halves, with both delicate ridged surfaces and also distinctively layered bone plates 

                                                          

I sent the images to Charlotte Dunn and Diane Claridge of the BMMRO in case the object might have something to do with a dolphin or even a whale. In their opinion it is very probably part of a ray’s mouth plate. It would be very interesting to know if anyone else has found an object like this. If so please respond in the comment box. Many thanks to Charlotte and Diane for sparing the time to help with ID

STOP PRESS I have some done further investigations into the dental arrangements of rays. I turned to the really excellent website of the Florida Museum of Natural History. On the FLMNH page for SPOTTED EAGLE RAYS is a very interesting photo by Cathy Bester which she has kindly given me permission to use. It is captioned Spotted eagle ray dentition: open mouth showing tooth bands and floor and roof of mouth  This photo seems to go a good way to confirming the ID of Kasia’s object, although obviously it might be a fragment from a different type of ray 

For the FLMNH site CLICK LOGO 

GO PRESS (or whatever an extra stop press may be): see comments  from Black River Fossils for further confirmation as a ray palate

 

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ABACO BEACHCOMBING FOR SEA GLASS WITH KASIA

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BEACHCOMBING FOR SEA GLASS 

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Kasia is an avid beachcomber on the sandy beaches of Abaco. Her collections include not only shells but also other marine debris such as sea glass. She has sent me some images with the comment “You can find a lot of sea glass in many different colours and shapes, from the most common green, brown and white through fairly hard to find colours like jadeite (one of the 2 forms of jade), citron, light blue, light green, honey and amber colored browns, to quite rare colors like cobalt, teal, periwinkle, aqua, amethyst & black” Here are some examples of Abaco sea glass from her collection. Shells and other items will follow as and when… 

SEA GLASS COLOURS: THE VITREOUS STATISTICS

Sea glass sources are many and varied. In general, these include old clear plates, glasses, windows etc; coloured drinks bottles – wine, spirits, beer, fruit, cola etc; soda bottles; medicine bottles (e.g. milk of magnesia / Vick’s blue); fruit jars; ink bottles; household goods (bleach, soda). The rarest colours (see below) come from very specific origins: teal / Mateus Rose bottles; red /  car or nautical lights or Schlitz bottles; black / c18 gin, beer and wine bottles

GENERAL CLASSIFICATION OF SEA GLASS COLOUR OCCURRENCE

Most common (1 in every 1 – 25 pieces found): clear, Kelly (‘Irish’) green, brown, blue, purple

Less common (1 in every 25 – 100 pieces found): jade, amber, lime green, forest green, ice / soft blue

Uncommon (1 in every 50 – 100 pieces found): other green shades

Very uncommon 1 in every 200 – 1000 pieces found): citron, opaque white, cobalt, cornflower blue and aqua

Extremely rare (1 in every 1000 – 10,000 pieces found): grey, pink, teal, black, yellow, turquoise, red

Rarest of all (1 in every 10,000+ pieces found): orange

Info credit: Magpies, for collection of bright shiny glass data. Omni-thanks

This is a helpful chart for the main colours, courtesy and © of  West Coast Sea Glass starting top left with orange as the rarest. The direct link is www.westcoastseaglass.com/rarity_chart_poster.html

You’ll find a great deal of other useful info on sea glass on Mary Beth’s  linked blog at http:// seaglassblog.blogspot.com/

There’s also a worthwhile Abaco Life article (2006) on sea glass at http://www.abacolife.com/2008/07/14/sea-gass-reveals-muted-tales-in-red-green-blue-white/ 

JAN 2012 I’ve noticed that there are several easily obtainable (eg from *M*Z*N) books on sea glass. I won’t be buying any to test-drive for you (as with birds, shells etc) – sorry – but they seem to be divided into the ‘pretty but uninformative and fairly cheap’ to the more instructive, more detailed and therefore more expensive books. It’s worth browsing online to find one that meets your interest level, whether passing or something more serious. The reviews are very useful here. The best – and it’s quite pricey – seems to be 

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ABACO BEACHCOMBING: TWO CONCH SHELL SKELETONS

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ABACO SHELL SKELETONS

Besides ‘living shells’ with occupants in residence and shiny recently-vacated shells, there is a third category of shell: the skeleton. I am sure there’s a better or more technical word for these. They aren’t fossils in the strict sense of remnants from a past geological age, but merely worn by the waves and bleached by the sun over time. Here are two examples (from different beaches) which show the intricacy of the part of the shell you don’t normally see: the interior

A shell skeleton from Little Harbour, in situ on the beach on a cloudy day

The same shell washed, with a wonderful pink tinge in sunlight

A strange corkscrew skeleton shell from Sandy Point. I’ve no idea what it is, nor how any creature can have lived in or around it, nor what it must have looked like when complete. Any ideas? Please use the comment box… Thanks, Kasia, for your ID of both as conch skeletons. The first obviously is, but the second puzzled me… until she pointed out that conchs build their own shells round themselves to their own designs rather than go to the one-stop conch shell shop. So if a conch starts wrapping itself comfortably round its own corkscrew, this is what you get

(Mrs rh quite rightly points out that my shell photos are unhelpful without a ruler to give an idea of size. Point taken. Too late. These are medium size…)

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BEACHCOMBING AT THE DELPHI CLUB, ABACO – CORAL & NERITES

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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