Susan J. Hewitt Curator

I am a serious amateur or semi-professional malacologist, originally from Britain, but now living in Manhattan, NYC. I joined iNaturalist in September 2014. I have had 49 scientific papers published so far. I am interested in both marine and non-marine Mollusca, shelled and shell-less; some people call me "the snail lady" or "the shell lady". I can identify most of the non-marine and marine mollusks of the British Isles (especially East Anglia); most marine mollusks of the West Coast of North America (especially San Diego); most marine mollusks of the East Coast of the USA (especially New York State); the Gulf of Mexico (especially Sanibel, Lee County, Florida); and the Caribbean Sea (Nevis, St. Kitts, St. Eustatius, and Montserrat).

I taught a college seminar at Yale on mollusks. I worked for two years at the Louis Agassiz Museum of Comparative Zoology, at Harvard, in the mollusk department. Starting in 2000, I volunteered at the American Museum of Natural History, first in the Malacology section of Invertebrate Zoology, and then, when the Malacology section closed, I worked in the invertebrate section of Paleontology. I am currently a Volunteer Emeritus at AMNH. I have given material to numerous museums in the US and the UK. Decades ago I did a great deal of fieldwork towards mapping the distribution of the land and freshwater mollusks of the British Isles, for the two published Atlases edited by Michael P. Kerney.

My forté is identifying mollusks, but I do also have some general natural history knowledge. I am learning to ID the spontaneous vegetation of NYC, and attempting to record the overall biodiversity of Randall's Island Park in Manhattan.

In June 2015, I was on a 3-week marine expedition to the Dutch Caribbean island of Sint Eustatius. Most years I am on the nearby island of Nevis for four weeks in April/May. I was in Southern California for three weeks in September, and I was on Sanibel Island in SW Florida for 16 days in mid-December.

On Wikipedia, I started editing in 2007. I was extremely active for a number of years. In 2011, my face and words were used online in a world-wide fundraising Wikipedia banner, and I was interviewed in the print, online, and broadcast media.

Currently I am trying to learn to identify the native non-marine mollusks of the US, a huge task. I already know many of New York City's non-marine species, the majority of which are introduced.

NOTE: I don't know the native non-marine mollusks of other parts of the world. However, I can probably recognize most species that were accidentally introduced.

ANOTHER NOTE: I changed my screen name here to my real name on September 23, 2016. Previously my screen name on here was "Invertzoo" -- I still use that name on Wikipedia.


ID-ing mollusks from photos can often be very difficult indeed, so I wrote these guidelines:


*** SCALE OBJECT -- In one photo please include a scale object (e.g. your fingertip or finger(s), a pen or pencil, a coin, or ideally, a small ruler). Without this, it can be hard for anyone else to guess the real size of the creature, which strongly affects the possible ID. If you pose a shell on your hand, the scale is automatically built-in:

*** SHELLED MOLLUSKS -- if the animal is alive, look around the immediate area and see if you can find an empty (full-grown) shell that is as fresh as possible. Using an empty shell (and sometimes even using a live animal), it is often not difficult to shoot three views from different angles (dorsal, ventral and lateral), including showing details of the aperture or the interior of the shell if it's a bivalve. Failing this, don't be shy to pick up the creature and turn it around this way and that for photographing. When you are done, put it back where it was, or nearby in a damp and safe place, with the aperture down.


*** With empty gastropod shells as well as live snails, please shoot more than one view, ideally three: dorsal, ventral, and lateral. At least photograph both the dorsal surface and a clear view of the aperture. If you can't find an empty shell, most live snails will retract if you prod them, and then you can get a shot showing the shape of the aperture, the nature of the operculum (in species that have one) and the color of the lip of the shell, where present.

ON THE LAND..................

*** Land snails:

If you find a group of snails that look more or less the same, always pick out whichever snail in the group has a relatively large shell where the edge of the aperture is sturdy and reinforced. That means it's an adult.

Juveniles can be almost as big as an adult, but the lip of their shell is very soft and still growing. We need to see a fully adult shell its a reinforced lip in order to see the characteristics that give rise to a reliable ID.

Even a dead empty adult shell is good for ID-ing the species, especially if the empty shell is fairly fresh still and not too bleached out.

Check these examples for the right ways to photograph a land snail shell:

*** Land slugs. One shot from above is often not enough to ID a slug. We usually need at least one additional close shot from the side. If possible, photograph the right side of the slug, which will show the position of the respiratory pore, and the markings around it. A scale object is almost always necessary.

Sometimes we need to see the shape of the tip of the tail of the slug, from the side. We also may need to be able to see the color and markings on the foot fringe, where the foot meets the substrate. The color of the sole of the foot of the slug is also often helpful to know (is it orange? white? longitudinally banded?) so please gently turn the slug over. The qualities of the body mucus (orange? colorless? milky when irritated? thick and sticky?) are also often helpful to know.

If a slug is contracted (or if a land snail is retracted) just pour a little water from your water bottle over it and wait a minute or two; usually the slug or snail will become active and extended.

BY THE WATER.................

*** Bivalves, whole or single valves? Please shoot the exterior square-on, NOT at an angle, and for empty valves, please shoot the interior too, square-on and in enough detail that we can see the hinge line. If the bivalve is very generic-looking, a lateral shot is also a good idea because it shows the three-dimensional shape of the shell.

*** Limpets? If possible, find an individual where the shell is is good condition (not eroded) with the sculpture intact. If you have an empty shell, photograph the outside, inside and a side shot. Remember that limpets can be very variable, so an image of just one individual in a population may sometimes not be enough to ID the species.

*** Chitons? Try to get some close shots of an individual where the shell valves are not too eroded or encrusted. We need to see the sculpture of the plates and the kind of girdle the chiton has.

*** Sea hares and sea slugs? Try as much as possible to photograph these while they are in water; out of the water their shape tends to collapse into a blob.



Land snails and slugs can leave behind them four kinds of tracks, trails or signs:

1. Shiny silvery dried mucus trails where they have moved along, often at night.

2. Grazing trails are left usually by slugs, but also by snails, on surfaces where they have fed on microscopic algae. These surfaces include tree bark as well as smooth human-made surfaces such as plastic, the glass of greenhouses, etc, as long as there are microscopic algae growing there.

3. Where land snails have rested for a while and then moved on, they often leave a small pile of poop behind.

4. When snails have again become active after having been inactive and withdrawn into the shell during a spell of dry weather (a state called "estivation"), they often leave behind flimsy broken remnants of an "epiphragm" -- a thin dried mucus layer that covers the aperture of the snail's shell. A snail secretes an epiphragm to prevent its soft parts from losing too much moisture while it remains motionless.

P.S. Do wash your hands before you eat lunch after handling land snails and land slugs; some carry parasites that can spread to humans.

P.P.S. Marine shells that are damaged and beach-worn may sometimes be impossible to ID to species, as may some other shells, and even some live animals.

P.P.P.S. There are more than 100,000 species of mollusk worldwide, not counting the as yet unnamed species which might double that total. I believe that no single person can identify more than a few thousand mollusks to species from memory.

Note: Even though I try to be conscientious, I do inevitably get some IDs wrong, especially because on iNaturalist I am always learning something new, and pushing the boundaries of what I understand, or what I think I understand. Please always feel free to put in a new ID, or to quiz me about an old one if you think it might be incorrect. Live and learn! :)

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